# Bijou All Tube Futterman Headphone Amplifier



## dBel84

I know there are a ton of DIY amps already on offer but thought some of you may be interested in this one too. 

 runeight has released his Bijou and many of us have already seen vixr's fine workmanship
1. 2. in the 'post pics of your build' thread. The official Bijou support thread and group buy for boards is over at Headwize but so many of "cross pollinate" that I thought it usefull to have a thread here too. 

 Further information regarding the details of the amp is available at runeight's web site, Cavalli Audio. 

 I can tell you from personal experience that this amp rocks and well worth consideration..dB


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## bhjazz

Thanks for the information! I've left a msg in the GB thread. 
 I had kind of lost track of the Bijou recently, so thank you!


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## amphead

I registered at Headwize a long time ago, but can't contact CMOY, to reactivate my account which lapsed. I'm trying to get in on the group buy for the 3 board set. thanks
	

	
	
		
		

		
			





  Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_I know there are a ton of DIY amps already on offer but thought some of you may be interested in this one too. 

 runeight has released his Bijou and many of us have already seen vixr's fine workmanship
1. 2. in the 'post pics of your build' thread. The official Bijou support thread and group buy for boards is over at Headwize but so many of "cross pollinate" that I thought it usefull to have a thread here too. 

 Further information regarding the details of the amp is available at runeight's web site, Cavalli Audio. 

 I can tell you from personal experience that this amp rocks and well worth consideration..dB_


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## vixr

amphead, let me know and I can always up my request to cover your boards...


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## ericj

The Bijou looks like a great amp, but i already have so many amps to build . . . .


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## dBel84

I have lost count how many I have built, the trick is to give them away so that there is not an ever growing pile to remind you that's it's time to stop. 
	

	
	
		
		

		
		
	


	




 The Bijou I have built is for a friend, and I rue the day that I have to box it up. I will at least know that it will bring a smile into his life. His request for me to build him an amp, coincided with the early rumblings of the Bijou pcb prototype and I knew that it was going to be first rate. 

 After living with it for the past few weeks, I know that I will have to build one for myself..dB


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## bhjazz

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_The Bijou looks like a great amp, but i already have so many amps to build . . . ._

 

Yikes! Me, too. I sat down and figured out where this one would sit in line, should I build everything that I have boards for. It looks like if I take a mere 1 to 2 months per project (an incredible pace for me, likely not even possible) I could start the Bijou in February...2009... 

 I guess the reason I keep buying boards is because it's often difficult to tell if they will be available in the future. If I knew they would be, I could easily hold off and just "put it on the list". But without that information, I just keep buying. I suppose I could just continue my trend and sell off the boards that I've changed my mind on; The price of them really doesn't depreciate!

 The one thing that makes this one even more enticing is that it could be available from Glass Jar Audio. Sourcing parts always eats up so much time for me, what with discussions about swapping caps, and parts options in general. Having a box of parts and boards would be quite a relief!


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## ericj

There's no estimated cost for the group buy boards? I suppose it probably won't be expensive . . . 

 Being a member of Team Cheap Bastards, I cringe at the thought of spending $200+ building the thing. Even though i know i probably wouldn't regret it. 

 The other problem for me is enclosures. I've got a few completed amps waiting for enclosures at the moment.


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## dBel84

I should join your cheap bastards team as I must be one of the cheapest bastards out there 
	

	
	
		
		

		
		
	


	




. I have yet to buy a commercial chassis, but then I don't own the masterpieces that the likes of AMB / Steinchen / Ferrari etc own. ( Vixr is excluded as he has "his own" mill and workshop = Team Lucky bastards 
	

	
	
		
		

		
		
	


	




 )

 A set of 3 boards will set you back $21 = 1 psu + 2 channels. 

 I can't comment on the cost of the kits as jeffr threw together a few proto kits at a very reasonable cost ( I could never have put it together for the same cost even excluding shipping - still don't know how he does it but he has a heart of gold ). The transformer alone will set you back about $70 with shipping, Angela has the best prices by far..dB


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## jamess71

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_There's no estimated cost for the group buy boards? I suppose it probably won't be expensive . . . 

 Being a member of Team Cheap Bastards, I cringe at the thought of spending $200+ building the thing. Even though i know i probably wouldn't regret it. 

 The other problem for me is enclosures. I've got a few completed amps waiting for enclosures at the moment._

 

 Included in this offer are 2 amp boards and 1 power supply board. $21 

 The info is in the marketplace subforum on headwize.


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## headphonejunkie

21 dollars. I have to get some just because they are so cheap. I have got to stop building amps.


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## ericj

Quote:


  Originally Posted by *jamess71* /img/forum/go_quote.gif 
_Included in this offer are 2 amp boards and 1 power supply board. $21 

 The info is in the marketplace subforum on headwize.
	

	
	
		
		

		
		
	


	


_

 

Ahh. In the metadata rather than the text of jrossel's post.


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## MisterX

Quote:


 There's no estimated cost for the group buy boards? 
 

Roughly $150 to complete the boards but that does not include the tranny or enclosure stuffs.


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## Uncle Erik

Sounds like I'm in the same boat as a few others. I'm a few amps and several enclosures behind, not to mention some speaker rig gear and 7-8 old radios.

 But I will order boards and parts. You never know when stuff will become unavailable, so it's best to buy and box it away.

 As for enclosures, I've been repurposing stuff found at swapmeets and junk stores. Anything can be painted to match and combined with other stuff. You have to be creative; I just figured out how to make solid state amp enclosures from some random heatsinks off eBay, offcuts of aluminum plates I found and some Hammond enclosures. The trick is not to put everything in one box, but instead use several bolted to the top and bottom of an aluminum plate. That lets you use a lot of boxes and parts that you couldn't otherwise and with great shielding, as well. I'll mix up the paint between flat black and black wrinkle paint to add interest. Not a traditional look, but it works. Hopefully, I can get a few of these done and pics up in January.


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## n_maher

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_The transformer alone will set you back about $70 with shipping, Angela has the best prices by far..dB_

 

What trafo does it use? I'm assuming a Hammond has been spec'd for availability's sake.


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## dBel84

My mistake , I recall it being more expensive 
	

	
	
		
		

		
			





 , it's these cysts in my brain!!

 "270DAX 75VA, sec. 260-0-260 @ DC ma 90, 6.3V @ 3.5A, upright mounting, bell ended EACH $40.99."

 ..dB

 shipping was ~ $15 ( I was thinking $50 +$15 )


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## bhjazz

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_The other problem for me is enclosures. I've got a few completed amps waiting for enclosures at the moment._

 

I desperately try to avoid having uncased projects, however tempting. That's probably why I take so long to complete projects: I expect them to be operational, cased, and ready for a meet at moment's notice! For the next projects, I will try to simplify the cases: less lighting effects, more audio, then MOVE ON TO THE NEXT ONE!!!!!!!

 Anyway, for $21 and ~$200, I'm definitely IN for this one. 

 ahhhhh....tubes.........


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## dBel84

speaking of uncased.......


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## runeight

Hello gents. Just signing in so I can get the emails. I think this will be the Bijou support thread on HeadFi. Thanks Don for starting it.


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## amphead

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Hello gents. Just signing in so I can get the emails. I think this will be the Bijou support thread on HeadFi. Thanks Don for starting it._

 

I'm in for the three boards. Like I mentioned earlier, I can't log-in to my headwize account. Thanks for having my back Vixr! Runeight has me on his list now, Right?  One question, you probably has this info listed, but are the tubes self-biasing or is there a biasing link? Thanks


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## bhjazz

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_speaking of uncased......._

 

Foam under the transformer, eh? Reminds me of a Bottlehead forum thread... 
 Those bell ends are itchin' for some polishin'.....


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## n_maher

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_My mistake , I recall it being more expensive 
	

	
	
		
		

		
		
	


	




 , it's these cysts in my brain!!

 "270DAX 75VA, sec. 260-0-260 @ DC ma 90, 6.3V @ 3.5A, upright mounting, bell ended EACH $40.99."

 ..dB

 shipping was ~ $15 ( I was thinking $50 +$15 )_

 

Someone should have a go at building the amp with the 370DAX. The voltage specs are exactly the same but the 370 is a lot more robustly designed. I've heard from multiple sources, and heard it myself, that over time the 200 series trafos have a habit of getting noisy, running hot, etc. I know that when I replaced the 200 series trafo in my Wheatfield with the equivalent 300 series the operating temp went down a good 20 degrees and the 300 was silent compared the rather buzzy 200.

 Just my 2c, and yeah, I'm in for a pair of boards or maybe more...

 Nate


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## Seaside

I am in for the boards, but not sure if I build it soon or not. And, Yes, I am one of the Team cheap person, and the Team Nude Amp FTW.


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## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I'm in for the three boards. Like I mentioned earlier, I can't log-in to my headwize account. Thanks for having my back Vixr! Runeight has me on his list now, Right?  One question, you probably has this info listed, but are the tubes self-biasing or is there a biasing link? Thanks_

 

Amphead, yes I'm on this thread now.

 The power supply has a trimpot to set to 250V. Other than this, everything is self biasing. Even if you tube roll.


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## MisterX

Quote:


 370HAX 
 

What? 
	

	
	
		
		

		
		
	


	




Hammond Mfg. - Universal Primary - "Classic" Power Transformer


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## n_maher

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_What? 
	

	
	
		
		

		
		
	


	




Hammond Mfg. - Universal Primary - "Classic" Power Transformer_

 

Sorry, transposed a letter wrong, it is of course the 370DAX. The trafo for my Wheatfield was a 370H so that's always the first part number that pops into my head...


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## MisterX

Ok, figured it was a typo but do you see the other "problem"?


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## n_maher

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_Ok, figured it was a typo but do you see the other "problem"?_

 

Nope. My understand was that between the 2 and 3 series there weren't any differences other than the universal primary specification and that the 3 series weren't built with "economy" in mind. So what's up? Or did I just screw something else up in my post that I'm too tired to find right now?


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## MisterX

270DAX:
  Quote:


 6.3 V@3.5 A 
 

370DAX:
  Quote:


 6.3V C.T. @ 3.5A 
 

the "Filament" winding on the 300 series has a center tap. 
 And. 
 the 300 series also has a "bias tap" 
 I realize those extra wires are non issues to experienced builders but I think both of us have been around here long enough to know that even if you explain it 14 times somewhere, someday, somebody is going to try to hook those extra wires up to the wrong spot.


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## n_maher

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_the "Filament" winding on the 300 series has a center tap. 
 And. 
 the 300 series also has a "bias tap"_

 

Good points, it certainly makes sense to have the 270 be the default and it's probably fine if the amp doesn't run hot. No doubt it's a lot easier to work with. But if someone was going all out the 370 would be worth considering in my book.


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## rb67

I have to say I am very happy with the performance of this amp. I built it P2P a few months ago and have been using it as my main amp. The transformer DOES get pretty warm and sometimes makes a high pitch whine (not in the headphone output, but physically) if it's been left on for a few hours. (I THINK it's the transformer). 

 Anyways, anyone building this amp should be very happy with the sound.


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## MisterX

Quote:


 But if someone was going all out the 370 would be worth considering in my book. 
	

	
	
		
		

		
			




 

You get no argument from me there.


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## dBel84

Quote:


  Originally Posted by *rb67* /img/forum/go_quote.gif 
_I have to say I am very happy with the performance of this amp. I built it P2P a few months ago and have been using it as my main amp. The transformer DOES get pretty warm and sometimes makes a high pitch whine...._

 

which transformer did you use? I know that runeight's amp runs hot but this is because the transformer was "underrated" for the necessary current requirements. The 270 DAX was chosen for it's higher rating. Mine gets warm, not unlike any of my other tube amps..dB

 The 370 looks like a decent alternative.


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## runeight

These are good points on the transformer.

 My original 270AX overloaded transformer (because I had it in the parts box) runs very hot, although it doesn't make any noise.

 The 270DAX will be running 2.8-3A for the heaters. That's close to the 3.5A rating and the heater winding will warm up for sure. But it should be far from overtaxed.

 The HV winding in the full wave mode will be supplying from 55-65mA depending on chioce of ECC99 or 6N6Pi. The rating on the HV secondary is 90mA so this winding is only operating at 2/3 capacity or less.

 My guess is that the transformer will warm up but it should not run hot. 

 rb67 which transformer are you using?

 Edit: Don, your post and mine crossed in the ether.


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## Jrossel

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I'm in for the three boards. Like I mentioned earlier, I can't log-in to my headwize account. Thanks for having my back Vixr! Runeight has me on his list now, Right?  One question, you probably has this info listed, but are the tubes self-biasing or is there a biasing link? Thanks_

 

I will put you into the list. We got your back (-:
 Could you email me your name and email address?


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## amphead

Quote:


  Originally Posted by *Jrossel* /img/forum/go_quote.gif 
_I will put you into the list. We got your back (-:
 Could you email me your name and email address?_

 

Thanks Jrossel! Done.


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## Mazuki

You can always use the R0080-036 model LiTe R-Core transformer.











 It's got way too many secondary windings, but that allows you to use 12.6V heaters in addition to 6.3V heaters. Mine never gets hot, and who says there's something wrong with overkill 
	

	
	
		
		

		
		
	


	




 I bought mine from VT4C (very trustworthy seller btw). The cost in the end was about $50, which is comparable to the Hammond DAX. R-cores are less noisy though and this one's higher rated.


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## dBel84

Good call mazuki - I had forgotten that you used the r-core. It also makes sense if you are trying to hide the transformer inside a slim chassis but be aware that like the 300 series , there are more secondaries to connect in places they don't belong..dB


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## fordgtlover

I'm new to the world of tubes 'n' such so please forgive me if this is a stupid question.

 The 270DAX is 117VAC primary. For 240VAC is the 370DAX the approriate replacement?


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## runeight

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_I'm new to the world of tubes 'n' such so please forgive me if this is a stupid question.

 The 270DAX is 117VAC primary. For 240VAC is the 370DAX the approriate replacement?_

 

Yes, that's correct.


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## dsavitsk

Quote:


  Originally Posted by *Mazuki* /img/forum/go_quote.gif 
_R-cores are less noisy though and this one's higher rated._

 

R and C and toroidal core power transformers have high bandwidth, which is bad in a tube PS as it allows HF noise to pass into the circuit. EI's, on the other hand, act as a natural filter to HF noise which is one of the reasons they are used in tube amps which generally don't reject PS noise well. You'll have to ask runeight what the HF PSRR of his regulator is to see if an R core is appropriate ... of you could add a choke instead of R7 or R8 -- I'd tend to do this anyway. Try a Hammond 158L -- high H, lowish DCR (about right for the circuit), decent current, and low cost. This will also allow you to lower the capacitance of C4 and C5 which would allow for a largish film cap, which would likely sound a little better.


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## runeight

Good point on the transformer noise. Leaving aside the tube, which will generate its own noise, the rest of the PS has a PSRR of about -100db at 10Hz and gets montonically better than this with increasing frequency.


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## hershann

As per Fordgtlover's post - i'll have to use the 370DAX series for the universal voltage - wiring it for 115v here and changing it to 240v when back home next year.

 So will appreciate when the build comes to learn which appropriate secondary wires to use. I presume that 6.3v CT means that it it 6.3v-0--6.3 and we will use the center wire as the reference ground?

 her shann


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## dBel84

Quote:


  Originally Posted by *hershann* /img/forum/go_quote.gif 
_I presume that 6.3v CT means that it it 6.3v-0--6.3 and we will use the center wire as the reference ground?
 her shann_

 

no it means 3.15 - 0 - 3.15 , you would therefore not use the center tap.

 ..dB


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## amphead

Thanks Dsavitsk! Putting a choke in, for the purpose of using large film caps on the output sounds good. The choke being a plus regardless to reject ps ripple.

  Quote:


  Originally Posted by *dsavitsk* /img/forum/go_quote.gif 
_R and C and toroidal core power transformers have high bandwidth, which is bad in a tube PS as it allows HF noise to pass into the circuit. EI's, on the other hand, act as a natural filter to HF noise which is one of the reasons they are used in tube amps which generally don't reject PS noise well. You'll have to ask runeight what the HF PSRR of his regulator is to see if an R core is appropriate ... of you could add a choke instead of R7 or R8 -- I'd tend to do this anyway. Try a Hammond 158L -- high H, lowish DCR (about right for the circuit), decent current, and low cost. This will also allow you to lower the capacitance of C4 and C5 which would allow for a largish film cap, which would likely sound a little better._


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## runeight

Quote:


  Originally Posted by *hershann* /img/forum/go_quote.gif 
_As per Fordgtlover's post - i'll have to use the 370DAX series for the universal voltage - wiring it for 115v here and changing it to 240v when back home next year.

 So will appreciate when the build comes to learn which appropriate secondary wires to use. I presume that 6.3v CT means that it it 6.3v-0--6.3 and we will use the center wire as the reference ground?

 her shann_

 

her shann the 370DAX has the same secondary windings as the 270DAX except for the CT on the heaters and a Bias Tap. If you will only be using your transformer for the Bijou you can cut the heater CT (not the HV CT!!) and the Bias Tap and wire the 370 identically to the 270. If you don't want to cut, just tape them off with good insulating tape or heatshrink. Follow the Hammond wiring color scheme and you should have no trouble.

 It's pretty easy to put a DPDT switch on the primary of the transformer so you don't have to actually rewire the circuit each time. However, you have to be really careful about flipping the switch to the wrong setting. 
	

	
	
		
		

		
			





 Chokes - chokes are great in tube PSs. I've used many of them myself. But be careful to think through the DC resistance of the choke. The two resistors R7 and R8 are calculated to drop a certain range of voltage so the the input to the to the regulator is high enough to keep the regulator regulating at 250V. The Hammond 158L has an R of 411 ohms. Depending on exactly how you use the choke this has to be thought through.


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## Pars

Actually they make special switches for voltage selection (do a search on Digikey for voltage select and choose switches when it comes back). These usually are marked 110/220 or whatever and require a screwdriver to switch them. Sample Digikey PN CKC3002-ND for example.


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## rb67

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_which transformer did you use? I know that runeight's amp runs hot but this is because the transformer was "underrated" for the necessary current requirements. The 270 DAX was chosen for it's higher rating. Mine gets warm, not unlike any of my other tube amps..dB_

 

I'm using the recommended 270 DAX.


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## dsavitsk

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_The two resistors R7 and R8 are calculated to drop a certain range of voltage so the the input to the to the regulator is high enough to keep the regulator regulating at 250V. The Hammond 158L has an R of 411 ohms. Depending on exactly how you use the choke this has to be thought through._

 

That choke has a DCR of 411R. It is replacing a resistor of 360R. The maximum current of both the rectifier and the transformer is 90mA, which means that the choke would drop, at worst, an additional ~5V. Differences in wall voltage will account for much bigger swings.

 Now, the bigger issue is that the current rating of the choke is only 75mA, and while Hammond rates their chokes pretty conservatively, that might not be enough. If that's the case, the 158M has a current rating of 100mA with a H of 10H and a DCR of about 200R, so it might be a better choice.

 And if it does run at close to 90mA, you might try an EZ81 instead of the EZ80.


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## runeight

Running a few comparison sims shows this:

 1. With the resistors only:

 279V input to regulator
 140uV of 120Hz ripple

 2. With a single choke and R8, R7, C5 removed:

 292V input to regulator
 500uV of 120Hz ripple

 The regulator has enough rejection to deal with the additional ripple in the case of a stand alone choke.

 The original PS heatsinking would not have been able to handle the extra power dissipation on the pass device (running at 42V and 55mA with the choke). But the new production boards have bigger heatsinks to increase flexibility for diy'ing the PS just for things like this.

 3. With R8 replaced with the choke and R7 reduced to 240R and with C4 and C5 reduced to 47u you'll about the same result as case #2 above.

 The maximum draw comes from using 6N6Pi tubes. It should be around 62-65mA. This is close to the max on this choke, and it will warm up some, but my guess is that it will work out alright.

 I'm not sure, however, that you will hear much difference in the audio with the choke hiding behind a sand regulator. I guess one of you guys will try it and let us know.


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## amphead

Hmmm..... to choke or not to choke.


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## runeight

LOL. Couldn't have said it better.

 But, this is an interesting idea. I decided to add a section to the Cavalli Audio website describing one way to do the choke in the PS. It's in the tweaks section. I may add some other ways to do it also, to give some choices.

 Although the original design expressly avoided big and heavy chokes, thanks for dsavitsk for suggesting the idea.


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## hershann

Just wondering about PS caps / ripples and such:

 1) If PS caps are there to reduce the ripples - I suppose the bigger the better (more expensive)? Is there concern that certain caps are slow to react and unable to react to transients? 

 2) As far as I can understand - chokes are there to reduce ripples but they drop the voltage - this allows smaller / better caps?

 3) Films caps are better than electrolytics as output / coupling caps - is that the same in the power supplies -> since no audio signal passes through them.

 4) Terminologies - what's coupling caps / what's decoupling caps.

 5) I see that some designs that has line suppression caps (small 0.0033uF example) across the AC terminals - is that to suppress EMF / filter out HF spikes from switching supplies noise. Any advantage or disadvantage to include in these amp designs?

 thanks

 her shann


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## runeight

1) Electrolytics have an internal inductance and resistance (actually all capacitors do, but electrolytics have more). The higher the frequency the more the inductance influences the behavior, reducing its behavior as a capacitor. The inductances are small and these frequencies are generally well above the audio band. But, as you note, it's the transients that matter. When a fast transient response is demanded from the amp this, in turn, demands a fast transient response from the PS. Large electrolytics will not respond as well as, say, good film caps. This is why many PS designers parallel film caps with the electrolytics or try to eliminate the electrolytics altogether.

 2) Chokes are very effective at filtering out the AC (including a lot of the lineside noise). The more effective the choke is, the smaller the caps can be.

 3) Film caps are always better than electrolytics, but they can't be made with large enough capacitance to be practical where large capacitances are needed, such as in power supplies. But, as noted in 1, the PS sees transients too and having film caps in the PS can be a benefit even if no "signal" passes through the PS. 

 4) Coupling caps couple the signal from one place to another, usually between one audio stage and the next. There are two coupling caps in the Bijou between the phase splitter and the output triodes. Decoupling caps do just the opposite. They placed in the circuit to prevent the signal from getting from one place to another. Most of the time decoupling caps are located on the PS rails so that when one stage causes the PS voltage to fluctuate the other stages are screened from these fluctuations. This keeps the stages from interacting with each other through the PS.

 5) Yes, those caps are to remove AC line noise. There is no disadvantage that I am aware of to including them in the build.


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## amphead

Anyone got their boards yet? Can't wait to get started. I will be using 370DAX/120VAC. Ordered 6n6p from Ukraine, Russian 71-74 military stock. I have Russian 6DJ8 in hand, marked "made in U.S.S.R." National brand. Might use high-end Japanese 9 pin sockets, $8.95 each(angela.com). What is the volume pot brand to use in this project?


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## Mazuki

Alps RK27 for the inputs and even for the NFB if you really wanted. Panasonic EVJ series is also good.


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## fierce_freak

I just payed for my kit last night. I haven't picked up tubes or a traffo yet, though.


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## amphead

Anyone heard of RK27 50k being used for the volume pot? Runeight?


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## runeight

There are only a few Bijous around at this moment, until more of you get your boards/kits. I'm not aware that any of them are using this pot.

 However, and good quality 50k or 100k will be suitable for the volume pot and should give you no problems.


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## fordgtlover

Does anyone have a source for the 370DAX?



 The website states:
_The Bijou is equipped with a variable NFB circuit. This helps the amplifier handle the range of headphone impedance from 32R to 300R._

 How will it go with 25 Ohm headphone such as the Denon D2000? Will I need to make any modifications?


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## amphead

Quote:


 Does anyone have a source for the 370DAX? 
 

Wish I could find an Aussie source for you, due to the weight. However, you can get one at Angela Instruments: Online Catalog in Maryland. Edit: give this a try first.

 There is a 370DAX in Queensland here.
Power Transformer and Choke Prices

 It might be cheaper to buy and ship from the US.


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## Mazuki

Quote:


 Anyone heard of RK27 50k being used for the volume pot? Runeight? 
 

Check this one out:


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## amphead

Thanks for the follow-up Mazuki! How does it sound?


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## fordgtlover

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Wish I could find an Aussie source for you, due to the weight. However, you can get one at Angela Instruments: Online Catalog in Maryland. Edit: give this a try first.

 There is a 370DAX in Queensland here.
Power Transformer and Choke Prices

 It might be cheaper to buy and ship from the US._

 

That's what I was thinking. I'll email them and ask about the freight.

 Thanks


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## Mazuki

Quote:


 Thanks for the follow-up Mazuki! How does it sound?  
 

Sounds very nice, smooth and punchy.


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## regal

Quote:


  Originally Posted by *Mazuki* /img/forum/go_quote.gif 
_Sounds very nice, smooth and punchy._

 

where did you get the case?


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## fierce_freak

Any reports as to the level this amp roughly performs at yet (B22/Dynahi level, CKKIII, EHHA, etc.)? I'll be starting this build in roughly a month and am just curious to about where it fits in line with other DIY offerings. I'm expecting to like it, of course...just the curiosity in me


----------



## Mazuki

Quote:


 where did you get the case? 
 

I had a friend buy it in China. I don't recommend using something like that. I have to run the amp with the cover off because with the lid on, it gets way too hot. 

 Those 6N6P/ECC99s really heat up. Mount them outside the case. I would suggest an entry level Hammond tube amp chassis (not those common extruded aluminum ones).


----------



## dBel84

go put someone on the spot 
	

	
	
		
		

		
		
	


	




 I think all the amps you mention are high fidelity, I haven't heard AMB's B22 or KG's Dynahi so my opinions would be limited on the solid state front but their reputation precedes them. I have been listening to the EHHA for several months but unfortunately that means very little as not many other people have and the bias of my listening preference confounds any "objective" opinions I may have. I spent a few hours comparing the Bijou to the EHHA, amongst others. I couldn't fault either amp in any musical presentation. They are both really fast amps, able to reproduce music with a wide dynamic range and not lose either their control over the bass (of which there is plenty) or their finesse in handling delicate midrange or highs. The soundstage is expansive and well defined. I had heard the expression "air around instruments" before but never got it until I had heard amps of this caliber. I compared them using Chesky's "golden ears" recordings and at a purely geek level they performed similarly and favourably on paper but when it came down to it, I seemed to enjoy listening to the Bijou more. I am not sure why this was, a new toy? the allure of multiple glowing tubes? the tube rectifier? 

 I will say that this amp will not disappoint, unless you live for hard edged analytical sound (which I believe excludes either of the SS amps mentioned too) . was that vague enough for you 
	

	
	
		
		

		
		
	


	




 ..dB


----------



## fierce_freak

Haha, thanks a lot for that, dBel84...very much appreciated


----------



## Mazuki

Quote:


 Any reports as to the level this amp roughly performs at yet (B22/Dynahi level, CKKIII, EHHA, etc.)? I'll be starting this build in roughly a month and am just curious to about where it fits in line with other DIY offerings. I'm expecting to like it, of course...just the curiosity in me 
	

	
	
		
		

		
		
	


	



 

I don't think this is a fair comparison necessarily because to my knowledge, this is the only all tube DIY headphone amp around. 

 That said, I would put it in the M^3 range in terms of complexity of build.


----------



## Mazuki

Quote:


 go put someone on the spot 
	

	
	
		
		

		
		
	


	




 I think all the amps you mention are high fidelity, I haven't heard AMB's B22 or KG's Dynahi so my opinions would be limited on the solid state front but their reputation precedes them. I have been listening to the EHHA for several months but unfortunately that means very little as not many other people have and the bias of my listening preference confounds any "objective" opinions I may have. I spent a few hours comparing the Bijou to the EHHA, amongst others. I couldn't fault either amp in any musical presentation. They are both really fast amps, able to reproduce music with a wide dynamic range and not lose either their control over the bass (of which there is plenty) or their finesse in handling delicate midrange or highs. The soundstage is expansive and well defined. I had heard the expression "air around instruments" before but never got it until I had heard amps of this caliber. I compared them using Chesky's "golden ears" recordings and at a purely geek level they performed similarly and favourably on paper but when it came down to it, I seemed to enjoy listening to the Bijou more. I am not sure why this was, a new toy? the allure of multiple glowing tubes? the tube rectifier? 

 I will say that this amp will not disappoint, unless you live for hard edged analytical sound (which I believe excludes either of the SS amps mentioned too) . was that vague enough for you 
	

	
	
		
		

		
		
	


	




 ..dB 
 

Thanks for sharing the flak dB 
	

	
	
		
		

		
		
	


	




, nicely put. 

 I'd like to point out though that this amp doesn't have the classic "tube sound" produced by traditional transformer coupled amps. In many regards, it's got that accurate and detailed sound of solid state amps.


----------



## dBel84

I have to agree with you there.

 I have never bought into the hype of tube amps sounding rounded with bloated floppy bass etc it has to do with design and a well designed tube amp is everybit as accurate as a well designed ss amp. I think the "clinical" ss amps are guilty of 'poor' bjt selection ( in hifi it was described as "Japanese" vs "English" sounding amps.) I put these in parenthesis as some folk prefer analytical and who am I to judge, I do know a good psychiatrist should they ever be in need of one though 
	

	
	
		
		

		
		
	


	




 ..dB


----------



## bhjazz

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_go put someone on the spot 
	

	
	
		
		

		
		
	


	


_

 

Thanks for going out on a limb with your perceptions. We all know how easy it is to get grilled around here for such an act! No worries. We'll bail you out!


----------



## dBel84

much appreciated 
	

	
	
		
		

		
		
	


	




 toying with the idea of crashing your party on the 22nd, time is a little tight but it would be fun..dB


----------



## Mazuki

I suspect once the group buy finishes and people complete their amps, there'll be plenty more people to share impressions and "flak" 
	

	
	
		
		

		
			





 The interest is pretty overwhelming for an amp that really has just left the prototype stage.


----------



## amphead

Kudos DBel84 and Mazuki! That helps those of us who are waiting in the wings and anticipating the golden flutter of notes entering our earholes.


----------



## bhjazz

Quote:


  Originally Posted by *MisterX* /img/forum/go_quote.gif 
_370DAX:
 the "Filament" winding on the 300 series has a center tap. 
 And. 
 the 300 series also has a "bias tap" 
 I realize those extra wires are non issues to experienced builders but I think both of us have been around here long enough to know that even if you explain it 14 times somewhere, someday, somebody is going to try to hook those extra wires up to the wrong spot. 
	

	
	
		
		

		
		
	


	


_

 

I'll easily take myself out of the experienced builders class, but the cavalliaudio site shows a pretty clear diagram of connecting the 270, including the center tap. 

 Ah, but I see the error of my ways. Would there be more than one CT wire on the 370? And would the bias tap wire just get lopped off and not used? (See...here's that "someday, somebody" thing you were talking about...)

 I think if the 370 is a more robust design, I'd sure like to just build the Bijou _one time _and then enjoy it from then on out!


----------



## n_maher

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_I'll easily take myself out of the experienced builders class, but the cavalliaudio site shows a pretty clear diagram of connecting the 270, including the center tap._

 

That's the CT of the high-voltage section, which the 370DAX also has. What Marshall was referring to was the fact that the filament (6.3V) portion of the 370 also has a CT, which you wouldn't want to use (as far as I can see, taking a quick look at it). But I'd want to look more into it before giving actual advice on how to wire it up for this amp. One thing is for sure, you are correct that you'd just ignore the bias tap all together.

  Quote:


 I think if the 370 is a more robust design, I'd sure like to just build the Bijou _one time _and then enjoy it from then on out! 
 

If it were me I'd use the 370 and just make darn sure to ask enough questions and do enough planning to be able to use it. It's certainly not that difficult if I can figure it out and not zap myself or the amp. Proceed with caution is the name of the game.


----------



## Mazuki

Just buy the 370DAX and when it comes time to wire it up, post some pictures and someone can help you out. It should be fairly straight forward.


----------



## regal

Its possible to use the 6H30 for the input which has half the gain. You could probably do away with the NFB, I suspect this would have very good sonics. T

 he problem is the 6H30 requires more heater current and I am not sure how to deliver this (no info on the Bijou website.)


 I am waiting on more detail on this and also the best price/benefit output caps. Someone used 330uF Auricaps which would be great for high Z phones but they are $180. I can't find any thing resembling a boutique 250V 470uF electrolytic.


----------



## dBel84

I am not sure what the heater capability is for the 370 and as far as I know, the only person who has attempted this mod is huskydawg over at headwize. He used a second transformer to supply the rectifier (heaters) and that enabled the 270dax to supply the amplifier boards .... iirc. In theory you could look for a transformer which has the appropriate secondary windings and heater supply necessary for the 6H30's. My recommendation is build the amp, if you really feel the need to modify, then follow the route that is discussed on headwize. I suspect that this will be cheaper than finding a transformer with a beefy heater supply..dB


----------



## Roam

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Its possible to use the 6H30 for the input which has half the gain._

 

Yes, but the resistor values for the front end will need to be adjusted to account for the differing characteristics of the tubes. A straight drop-in of the 6H30 would place it at a fairly non-linear operating point. A more robust transformer will also be needed as the 6H30 uses a lot more heater and plate current than 6922 when operating in its linear range.

  Quote:


 You could probably do away with the NFB, I suspect this would have very good sonics. 
 

No, you can't, unless you only use 600 ohm headphones such as the AKG K240M. NFB is required to reduce the output impedance so that it can drive medium to low impedance headphones.


----------



## regal

Quote:


  Originally Posted by *Roam* /img/forum/go_quote.gif 
_Yes, but the resistor values for the front end will need to be adjusted to account for the differing characteristics of the tubes. A straight drop-in of the 6H30 would place it at a fairly non-linear operating point. A more robust transformer will also be needed as the 6H30 uses a lot more heater and plate current than 6922 when operating in its linear range.



 No, you can't, unless you only use 600 ohm headphones such as the AKG K240M. NFB is required to reduce the output impedance so that it can drive medium to low impedance headphones._

 


 All you have to do is change the cathode resistor to 5.1k.

 Are you sure about the NFB? I think it won't be needed with 6H30, its more linear than the 6922, the Zo only climbs up to 32 ohms with no NFB. I don't see any problems with Senns with this output impedance. I think the NFB is mainly to reduce gain unless you are trying to listen to Grado's or Denon's with a tube amp! Low Z phones are meant for Solid State IMO.


----------



## Roam

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_All you have to do is change the cathode resistor to 5.1k._

 

Wrong. Absolutely wrong. Running a 6H30 at ~1mA which is what your proposed change will do is beyond stupid. Have you even looked at the curves & specs of a 6H30? The tube is practically in cut-off at your proposed operating point, there will be loads of distortion and the tube may even shut off entirely at higher volumes. 6H30s need at least 10mA going through them, preferably around 20-30mA depending on the plate voltage.

  Quote:


 Are you sure about the NFB? I think it won't be needed with 6H30, its more linear than the 6922, the Zo only climbs up to 32 ohms with no NFB. I don't see any problems with Senns with this output impedance. 
 

A 6922 operating into a 100k plate load is going to be quite linear, and the same is true of the phase-splitter portion. It is far more linear than the 6H30 in the same circuit, let alone your proposed 6H30 circuit. The 6H30 is more linear than the 6922 only if the circuit is optimized for it, which is not a trivial task given the voltage constraints and the need to keep current draws and so forth in a manageable range without blowing the budget.

 With regards to NFB and output impedance, 32 Ohms is too high unless you're using Sennheisers or the 600 Ohm AKGs. It's unacceptable with Grados, K701s, Audio-Technicas, Denons, and Ultrasones among others.

  Quote:


 I think the NFB is mainly to reduce gain unless you are trying to listen to Grado's or Denon's with a tube amp! Low Z phones are meant for Solid State IMO. 
 

It's there to adjust the Zo so that a sufficient damping factor is provided for the headphones. 

 Also, driving low Z headphones with a tube amp is a trivial task, it's called using an output transformer and/or using the right tube. With a transformer I can drop the Zo into the low single digits with ease, an OTL with the right tubes can easily have a Zo in the single digits, good enough to drive Grados.


----------



## regal

Quote:


  Originally Posted by *Roam* /img/forum/go_quote.gif 
_

 It's there to adjust the Zo so that a sufficient damping factor is provided for the headphones. 

 Also, driving low Z headphones with a tube amp is a trivial task, it's called using an output transformer and/or using the right tube. With a transformer I can drop the Zo into the low single digits with ease, an OTL with the right tubes can easily have a Zo in the single digits, good enough to drive Grados._

 


 The designer of the Bijou recommends the 5.1k cathode resistor its under tweaks here:

The Bijou Stereo Headphone Amplifier

 I don't think his designs are stupid, in fact I greatly appreciate that he shares his designs, 

 As far as low Z phones with a transformer output, the tube is doing very little right I mean how much gain do you need with 30 ohm headphones?


----------



## Roam

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_The designer of the Bijou recommends the 5.1k cathode resistor its under tweaks here:

The Bijou Stereo Headphone Amplifier

 I don't think his designs are stupid, in fact I greatly appreciate that he shares his designs,_

 

And he'd be wrong. It appears he's looking at the voltages of the circuit without regard to the operating point of the tubes. The 6H30 will work, but it'll be far from optimal and a complete waste of the tube's capabilities. The 6H30 is a lot closer to an ECC99 than a 6922, it's a driver tube which is meant to be run with a fair bit of current, it's not happy being run at a couple mA, it wants a couple dozen mA for best results.

  Quote:


 As far as low Z phones with a transformer output, the tube is doing very little right I mean how much gain do you need with 30 ohm headphones? 
 

Current. Not much voltage gain is needed, but a fair amount of current may be required.


----------



## regal

Quote:


  Originally Posted by *Roam* /img/forum/go_quote.gif 
_ Not much voltage gain is needed, but a fair amount of current may be required._

 


 Which is the realm of solid state, just my personal preference to keep low Z phones away from tubes. I just don't see the point.

 Thanks for the info about the 6H30, I think I will nix that idea.


----------



## Mazuki

Quote:


 You can always use the R0080-036 model LiTe R-Core transformer.











 It's got way too many secondary windings, but that allows you to use 12.6V heaters in addition to 6.3V heaters. Mine never gets hot, and who says there's something wrong with overkill 
	

	
	
		
		

		
		
	


	




 I bought mine from VT4C (very trustworthy seller btw). The cost in the end was about $50, which is comparable to the Hammond DAX. R-cores are less noisy though and this one's higher rated. 
 

The transformer I used has 6A of filament power. It also has the 260-0-260 tap. 

 It's also cheaper than the 370DAX.


----------



## dsavitsk

Quote:


  Originally Posted by *Roam* /img/forum/go_quote.gif 
_Wrong. Absolutely wrong. Running a 6H30 at ~1mA which is what your proposed change will do is beyond stupid._

 

Roam, you need to cool it. Whether you are right or wrong, the DIY forum only works due to collegiality. Whether you agree with his design philosophy or not, the designer of that amp is a talented and respected designer. If you think he has made a mistake, please post it, but do so in a respectful manner. There isn't a lot of moderation here, but you will find yourself on a lot of ignore lists pretty quickly.


----------



## dsavitsk

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Which is the realm of solid state, just my personal preference to keep low Z phones away from tubes. I just don't see the point._

 

A tube with a transformer is an excellent way to driver low impedance phones, particularly in light of the very benign impedance curve. It turns out that tubes and transformers are very linear devices, much more so than transistors. Transistors require much more work than tubes to make them linear.


----------



## amphead

Quote:


 And he'd be wrong. It appears he's looking at the voltages of the circuit without regard to the operating point of the tubes. The 6H30 will work, but it'll be far from optimal and a complete waste of the tube's capabilities. 
 

Roam, you are very talented and your advice will get the respect it deserves alot more with honey than vinegar as Dsavitsk suggests. Dsavitsk is also someone I respect for his knowledge, as he is very often correct.(JMHO)

 Where's my Bijou boards? Get in my belly.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Where's my Bijou boards? Get in my belly._

 

Big LOL over here, amphead! My wife saw your post and almost spit her coffee out!

 I agree. I think we killed Jeff!

 On another note, amphead, when you get done with your Bijou, I'll be interested to know your impressions between this amp and the Millet Max. I have a Max board staring at me, but since I opted for a kit for the Bijou from Jeff, it will get done first.


----------



## amphead

My humble apologies Jeff! Checked my mailbox and realized the boards were already there, 48 hours ago. Greased lightning shipping on some beauuuutiful boards.


----------



## amphead

Quote:


 On another note, amphead, when you get done with your Bijou, I'll be interested to know your impressions between this amp and the Millet Max. 
 

Well, I almost know what to expect. The Bijou and the MAX will emphasize different aspects of the frequency response. The Max with its tight Bass and articulate Highs, and the Bijou with pronounced and addictive Mids, giving vocals that sweet and expressive presentation. Of course when I finish my Bijou, there will be a full report.


----------



## amphead

btw, Thanks Jrossel, I think Alec will enjoy building the Bijou. He wants to use a toroidal. Anyone using a toroidal for the project?


----------



## bhjazz

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_much appreciated 
	

	
	
		
		

		
		
	


	




 toying with the idea of crashing your party on the 22nd, time is a little tight but it would be fun..dB_

 

Wow, I just saw this post tonight. That would be excellent, and we'd be happy to have you be there!


----------



## amphead

Waiting on my tube socket shipment and then, I will start building. Can't wait to hear the Bijou!


----------



## bhjazz

comments edited.


----------



## dBel84

He's about, busy as always but getting things done. why not e-mail him, it looks like some communication has gone awry or he has not updated the status posted on headwize..dB


----------



## ericj

A few misc questions. I was going to ask these on headwize but hw wants me to verify my email again, but isn't sending the verification email. I suppose I'm still within the "one or two days" window on email verification there, but golly. I'm not going to wait two days. 

 Anyhoo. First, tube questions. 

 I see a lot of 6n6p around the web sold as equivalent to ecc99. Not 6n6p-i, just 6n6p. Are these truly equivalent? 

 Also, I'm idly wondering if 6n23p is a possible 6dj8 equivalent for this amp. The only potential issue i see is the relatively low maximum plate voltage (100v, 90v for the -ev version). Although I'm more likely to try and use some 6n1p-ev i already have. I'm aware of the filament current requirements. 

 Lastly, I'm kinda wondering if i can use the pictured transformer with the 220v b+ version of the circuit:


----------



## dBel84

Hi Ericj

duncanamps have a link to Franks web site where both pdf's can be downloaded. The tubes are slightly different in spec but similar enough to be interchangeable - unless I missed something in the spec sheet. 

 The transformer may be a little underpowered for these tubes though = Alex mentioned that the 6n6pi have a different cathode resistance and thus have a higher current requirement than the ec99's - the rated 65mA HV is barely sufficient , I suspect 40mA is a little low but the designer will be able to be more specific in this regard. The heater windings are obviously insufficient. 

 glad to see you taking this one on and looking forward to comments..dB


----------



## ericj

i admit that the printing on this trafo is confusing but where are you getting 40ma? the hv secondaries are labeled 50ma, just like the hammond 270ax. there is also that very confusing '0.065a total' marking there. 

 As for the heater windings, may i draw your attention to the 3.75A heater winding on the lower left.


----------



## n_maher

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_i admit that the printing on this trafo is confusing but where are you getting 40ma? the hv secondaries are labeled 50ma, just like the hammond 270ax. there is also that very confusing '0.065a total' marking there._

 

I would take the "0.065a total" to mean that you can use both of the high voltage secondaries (90 and 235, since they have the * marker) provided the total current draw limit of .065A is not exceeded. 

 I guess the real question is whether or not it's worth risking ~$40 to find out if does work.


----------



## dBel84

my apologies - I somehow read the 0.005 as a 0.004 and completely missed the heater on the left and only saw the measly 600mA on the right. I would still check with Alex re the 50mA and the 6n6p tubes, I recall a discussion that they were not suitable for his build which used the 270AX. The recommended transformer is the 270DAX which has an HV current rating of 90mA. It still seems suitable for the 220V build with the ecc99 original Bijou though. AND this heater supply will not make the tranny run hot 
	

	
	
		
		

		
		
	


	




 ..dB

 edit - seems nate's post crossed while a was scouring old e-mail discussions - good poitn re the total HV current supply at 65mA

 yet another edit: the psu needs a centre tapped 240-0-240 or 260-0-260


----------



## amphead

Tube sockets soldered on. Just wanted to see those tubes mounted......he he  Wondering how it sounds with K701? Low impedance. Anyone know?


----------



## bhjazz

Quote:


  Originally Posted by *n_maher* /img/forum/go_quote.gif 
_I would take the "0.065a total" to mean that you can use both of the high voltage secondaries (90 and 235, since they have the * marker) provided the total current draw limit of .065A is not exceeded. _

 

Geez I love this place. Where on earth could I ever have learned _that_! Coolio!


----------



## amphead

Step two, deciding on the layout, for my stainless substrate.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Step two, deciding on the layout, for my stainless substrate. _

 

Wow, you're really crankin along there, amphead. I think I resolved my my previous issues (and apologize if my post looked cranky) and the parts are on their way.


----------



## rhester

What fuse size would be appropriate for this amp? Slo blo or quick acting? 

 Almost finished and almost ready to start testing.


----------



## Mazuki

Quote:


 Step two, deciding on the layout, for my stainless substrate. 





 

I'm not so sure about mounting those tube sockets first. It's going to be hard to solder the small stuff, like the resistors and diodes.


----------



## amphead

Quote:


 I'm not so sure about mounting those tube sockets first. It's going to be hard to solder the small stuff, like the resistors and diodes. 
 

True, but in many ways this build is going to be reasonably easy. I am working on some aesthetic aspects of my chassis design. Just purchased some Cocobolo to dress up the sides of the case. I wanted to look at the height of the tubes to get ideas for keeping fingers out of the HV regions, while still allowing those beautiful boards to show.


----------



## rhester

Mine, for now is going on an old fashion looking Hammond chassis with the big cage. Powered it up last nite and have 5 glowing tubes. Planning on finishing up the rest of the wiring over the weekend and plugging in. Hopefully post some pics after.


----------



## amphead

Great news, looking forward to seeing your pics and evaluation.


----------



## amphead

Ordered 80% of my parts. On the hunt for the large electrolytics and film caps. Should be stuffing my boards by midweek.  Some more chassis work tomorrow.


----------



## Mazuki

Quote:


 Ordered 80% of my parts. On the hunt for the large electrolytics and film caps. Should be stuffing my boards by midweek.  Some more chassis work tomorrow. 
 

Try one of these photo flash capacitors for output (C5) cap. Their fast discharge characteristics are better for output coupling.


----------



## rhester

Finished casing this up this morning. Just plugged it in 15 minutes ago and powered it up.

 WOW. 

 Very nice bass, not flabby but plenty deep and popping. Great silence between notes on the current jazz selection. Nice high end sparkle. Big soundstage. Can't wait to burn it in and see what this is trully capable of.

 Here are some pics. My casing leaves a little to be desired, but hope to change to a nice wooden case soon and spruce it up a little.


----------



## willisv

Nice job rhester! I should have mine fired up late tonight.


----------



## amphead

Awesome work Rhester!
 And thanks for the advice Mazuki! Maybe 

 Heres the bare chassis that I built w/oak.






 Heres the amp substrate laying on top unmounted. Cocobolo faces will be glued to the oak. Solid 24kt gold volume knob optional


----------



## amphead

Well Mazuki, now you've gone and done it. I purchased the Rubycon photo flash 410uF 300sv ouput caps. Its true, that since we have to block the DC in this design, that output caps are a neccessity. I might as well have the step up there. Hope the bass extends deep enough with 410uF vs 470uF.


----------



## Mazuki

Quote:


 Well Mazuki, now you've gone and done it. I purchased the Rubycon photo flash 410uF 300sv ouput caps. Its true, that since we have to block the DC in this design, that output caps are a neccessity. I might as well have the step up there. Hope the bass extends deep enough with 410uF vs 470uF.  
 

Well, that's where you add another film cap, a Russian PIO or something, in parallel with it. You're lucky to have the production boards with the film cap trace on the board.


----------



## amphead

95% of the parts have been ordered. Still need IRF820B, and found IRFS820B, which I think is the same part. Still need the Xicon metallized box caps. And need an EZ80. Tomorrow, I will cut and glue the Cocobolo to the Oak sides and top edge of the chassis.


----------



## runeight

amphead if you can't locate irf820 you can use the Fairchild FQP4N50. The last time I looked, these were available at Mouser. They are listed on the Bijou web pages Parts List as a straight sub for the IRF mosfet.


----------



## runeight

For some reason I haven't been getting email notification on this thread for a while. I've gone back a few pages to read the discussions.

 In one segment Roam is talking about the operating point in the front end.

 Any amp involves trade-offs. In this case, there was a current budget for the PS, a desire to not use a CCS for the plate load on the gain stage, and a desire to use the same B+ for the input and output stages to keep the transformer requirements to one HV secondary. Many of these trade-offs were to keep the cost down so that the amp $$ budget could fall into a realm where many diyers who wanted a tube amp could build one while still making a very good sounding amp.

 The amp was originally designed to only use 6922s for the input stages. Nevertheless, there were quite a few folks who wanted to try 6N1P and 6H30 and I felt that the best answer was to provide a value for the cathode resistor that would set the voltage op points correctly. This is a better solution than having builders directly sub these tubes with no changes because not changing the cathode resistor really messes up the amp and, well, some folks were going to do this whether it was a good idea or not.

 Some of the reviewers have simply substituted 6N6P into the front end and then noticed that, when they put 6922s in, the amp sounds a whole lot better. 
	

	
	
		
		

		
			





 The 6922 is running a bit lean in the first two stages. Doing so lets us use the 100k plate resistor to get a respectable curve from the 6922 without a CCS. But it is still running in the lower part of the plate curves where it is less linear than if we were running 10mA through it.

 A 6N1P also runs a bit lean and at less than optimum voltages. Adjusting the cathode resistor sets the voltage operating points to where they should be for the amp and lets the 6N1P function reasonably well.

 The 6H30 is a bit more problematic because it really wants to run at higher idle currents. But the amp is not designed to support 10mA in the front end on both channels. So the 6H30 has to run lean too.

 Most folks tend to judge an amp, ultimately, by the way it sounds and it was clear that most of the builders wanted roll the at least one or two tubes in and out to decide which ones they liked best. Some folks are liking the sound of the 6H30 even though it is not in optimal operating condition.

 Well, who am I to say who is right when it comes to nuances in the sound? I want everyone to use 6922s because that's what I designed, but when you build it it's your amp. 

 On the NFB. The NFB has two purposes. First, as Roam said, it lowers the Zo for low Z headphones. It also reduces the THD for the lower Z headphones. Driving 32R directly is not easy for the output tubes. Some of their non-linearities become more prominent. The easiest way to fix this is to provide some amount of NFB. The NFB also has the added effect of reducing the gain so that the vol pot has some range for the low Z headphones.

 Prototypers have also noticed that the adjustable NFB affects the sound stage in a way that the listeners can easily hear. Different listeners find different settings that suite their listening styles.

 I hope this clarifies some of the thinking behind a few of the things that are happening with this amp. If not, please let me know.


----------



## willisv

I finished my Bijou this morning and it is working great. Other than a loose heater wire there was no problems getting it running. I have been listening to it all day and it is sounding very nice. This is the only amp I own that can drive my K701's with authority. As far as listening impressions, it is still breaking in but so far it has exceeded all my expectations. Thanks to Alex for designing this amp and making it available to Diy'ers and to Mike for helping me build and troubleshoot.


----------



## Nebby

willisv, where did you pick up that nice terminal strip? I've been looking for that style term strip for some time and haven't been able to find any


----------



## willisv

Quote:


  Originally Posted by *Nebby* /img/forum/go_quote.gif 
_willisv, where did you pick up that nice terminal strip? I've been looking for that style term strip for some time and haven't been able to find any 
	

	
	
		
		

		
		
	


	


_

 

I just found it on the shelf of my local electronics shop. You could also use the screw head type (don't know what they call it) and put lugs on your wires.


----------



## Tedro

Quote:


  Originally Posted by *Nebby* /img/forum/go_quote.gif 
_willisv, where did you pick up that nice terminal strip? I've been looking for that style term strip for some time and haven't been able to find any 
	

	
	
		
		

		
		
	


	


_

 

I have seen them at Radioshack


----------



## runeight

Really nice job willisv. I wish that my wiring were that clean.

 Glad you like the amp too.


----------



## Nebby

Quote:


  Originally Posted by *Tedro* /img/forum/go_quote.gif 
_I have seen them at Radioshack_

 

Now if only they had radio shacks in Japan, I'd be set! 
	

	
	
		
		

		
		
	


	




 I'm slowly digging thru the Digikey catalog, and I think I might have found some, was just wondering where other folks got theirs. 

 BTW, great build willisv. I hope mine will be as cleanly done. How hot does it get? 

 I'm planning on building a balanced Bijou amp once I get the chance, have a few other projects lined up first though.


----------



## runeight

Nebby, willisv has done a brilliant job on his wiring.

 But, it is not necessary to use additional terminal blocks to wire the Bijou completely. There is a section at Cavalli Audio that describes the procedure for wiring without addtional terminals.

 Please let me know if this does or does not help.


----------



## willisv

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Really nice job willisv. I wish that my wiring were that clean.

 Glad you like the amp too. 
	

	
	
		
		

		
		
	


	


_

 

Thanks, next time I won't use car battery cable to wire though


----------



## holland

willisv, what case is that and it looks like it barely clears the tubes. How much headroom in the case is there?


----------



## Nebby

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Nebby, willisv has done a brilliant job on his wiring.

 But, it is not necessary to use additional terminal blocks to wire the Bijou completely. There is a section at Cavalli Audio that describes the procedure for wiring without addtional terminals.

 Please let me know if this does or does not help._

 

Oh I'm well aware that the Bijou doesn't require a terminal strip to be wired up. I'm looking to stock up on them for some other projects where having one will make the cabling much neater 
	

	
	
		
		

		
		
	


	




 Btw, are there any concerns I should take into consideration if I am going to build a balanced version? Aside from the wiring changes for input/output and the need for two sets of PS/2x amp boards.


----------



## willisv

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_willisv, what case is that and it looks like it barely clears the tubes. How much headroom in the case is there?_

 

The tubes are sticking out but I'm probably not putting a cover on it. If I do it will be a mesh screen of some sort, this thing puts out a lot of heat. The case is a steel Hammond part# HAMMOND 1441-24 from parts connection. It is 12" x 8" x 3".


----------



## amphead

Willisv, awesome work man! Thanks for letting me know how good it sounds with K701's.
 Also, thanks Runeight!

 Here's my rig at the 60% finished state, with Cocobolo glued on.


----------



## willisv

That case is looking nice amphead! Are you going to put a cover on it?


----------



## amphead

No, but there will be a guard that prevents fingers from coming into contact with the High Voltage. I am still thinking about how I want to do that. Thanks


----------



## jamess71

Williesv Very nice. I have one on order myself, kit from Jeff. Thats some pretty heavy hookup wire you used. 
	

	
	
		
		

		
		
	


	




 I have another Millet Max in queue first though. 

 James


----------



## runeight

Quote:


  Originally Posted by *Nebby* /img/forum/go_quote.gif 
_Oh I'm well aware that the Bijou doesn't require a terminal strip to be wired up. I'm looking to stock up on them for some other projects where having one will make the cabling much neater 
	

	
	
		
		

		
		
	


	




 Btw, are there any concerns I should take into consideration if I am going to build a balanced version? Aside from the wiring changes for input/output and the need for two sets of PS/2x amp boards._

 

OK. Just wanted to be sure.

 There is no special treatment other than the input/ouput wiring and pots for a balanced version.


----------



## da_burl

Amphead, that is almost exactly what I have designed, in my mind at least!!

 Also wracking my brain for ideas for some sort of cover, I'm thinking acrylic/lexan, or possibly expanded metal, if I can figure out how to work with these materials! Or possibly the largest drawer pulls at Home Depot 
	

	
	
		
		

		
		
	


	




. But the single sheet of aluminum on a wood base is right up my alley!


----------



## willisv

Quote:


  Originally Posted by *jamess71* /img/forum/go_quote.gif 
_Williesv Very nice. I have one on order myself, kit from Jeff. Thats some pretty heavy hookup wire you used. 
	

	
	
		
		

		
		
	


	




 I have another Millet Max in queue first though. 

 James_

 

That's awesome, you will have fun building the Bijou. Make sure you find a 100k 1 or 2 watt bleeder resistor to drain the big caps.


----------



## bhjazz

Nice work willisv!

  Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Here's my rig at the 60% finished state, with Cocobolo glued on._

 

Nice work there amphead. I see that you build very much like I do: lots of case work started even before all the soldering is done. 
	

	
	
		
		

		
		
	


	




 The casing always take me so much extra time! Oy! But I figure hey, I've gotta look at this thing from here on out. It might as well look cool.

 With your wood and metal work, perhaps instead of just having a cage you might consider building a Cocobolo frame which you can attach the caging material to. This would visually bring the wood upwards from the base and give it more visual "flow". Just a thought. 

 Have fun!


----------



## dsavitsk

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_No, but there will be a guard that prevents fingers from coming into contact with the High Voltage. I am still thinking about how I want to do that. Thanks_

 

A solution I have used is to solder the components, except for the tube sockets, to the bottoms of the boards. Put the sockets on top and hang the boards under the top plate with some standoffs and cut holes for the tubes to poke through. A very sloppy version of this type of construction can be seen here: ecp.cc


----------



## amphead

Thanks for the info Dsavitsk. Thats a beautiful amp! The boards in this design have some tall heatsinks, caps and other things that get in the way. (Although, if those components were mounted underneath the pcb, it would work). But, as they are mounted now, it means my tubes don't show nicely like in your design. There would be difficult cuts into my stainless top to make it work. I may have decided to only partially block fingers from HV. The top edges might get a 2 and 1/2 inch tall perimeter of 1/8 glass in the front and the 2 sides and the backplane with another material. Then the tubes and boards would show. The added weight would be a drawback however, because it is getting heavy already, without the 370DAX.  Edit: lucite probably doesn't do well with the heat, and a cage mesh is ugly.

  Quote:


  Originally Posted by *dsavitsk* /img/forum/go_quote.gif 
_A solution I have used is to solder the components, except for the tube sockets, to the bottoms of the boards. Put the sockets on top and hang the boards under the top plate with some standoffs and cut holes for the tubes to poke through. A very sloppy version of this type of construction can be seen here: ecp.cc_


----------



## Mazuki

You can get drill bits for those tube holes here:

Audio Catalog


----------



## dBel84

Quote:


  Originally Posted by *Mazuki* /img/forum/go_quote.gif 
_You can get drill bits for those tube holes here...._

 

This is a great resource - have been looking for this type of drill for some time , I see punches from time to time but never sure how well they would work on steel. 

 I have yet to finalise the chassis but I plan on sticking the amp tubes through the top plate and house the transformer and psu in a protective "cage" behind the tubes. For anyone interested in a similar approach, the DAZ version of the transformer sits lower on the top plate and is approximately the same height as the assembled psu - allows for the cage part to be about 3in. 

 I know that there are some out there who have figured a way to mount that psu heatsink on the underside too and that really gets rid of all the possible issues of putting all the tubes on the top.

 this is what my "naked" boards look like..dB

 top 
	

	
	
		
		

		
		
	


	




 bottom 
	

	
	
		
		

		
		
	


	




 psu


----------



## hershann

Mine's sorta done - except for the temporary chassis (described by somebody as a cardboard honeycomb monocoque chassis with integrated airvents) . 

 1st pic -shows the airwiring of the PS tube socket

 Amp tube sockets are right way up but PS tube socket is air-wired from below so the heatsink can stay on the correct side.


 her shann


----------



## Mazuki

Quote:


 This is a great resource - have been looking for this type of drill for some time , I see punches from time to time but never sure how well they would work on steel. 

 I have yet to finalise the chassis but I plan on sticking the amp tubes through the top plate and house the transformer and psu in a protective "cage" behind the tubes. For anyone interested in a similar approach, the DAZ version of the transformer sits lower on the top plate and is approximately the same height as the assembled psu - allows for the cage part to be about 3in. 

 I know that there are some out there who have figured a way to mount that psu heatsink on the underside too and that really gets rid of all the possible issues of putting all the tubes on the top.

 this is what my "naked" boards look like..dB 
 

Aren't you going to mount the rectifier tube on top too? It also gives off quite a bit of heat and is at least as tall as the 6N6P.


----------



## dBel84

Yeah it will go on the top but it will be enclosed in a "cage" - I am having trouble finding exactly what I am after, when I do it will finished. 

 here is a 3d sketch up of the concept - the proportions are not correct but the idea is there..dB


----------



## amphead

Great work DBel84! I guess what I am going to do ( like Dsavitsk suggested ), is get the amp working first and then desolder the tall components ( almost all are currently mounted and soldered ) and mount them under the pcb. It wont be too bad, because the resistors can stay on the top of the pcb. I just hope that the heatsinks on the mosfets don't damage the power supply board, with the heat updraft onto the board.


----------



## dcheming

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Great work DBel84! I guess what I am going to do ( like Dsavitsk suggested ), is get the amp working first and then desolder the tall components ( almost all are currently mounted and soldered ) and mount them under the pcb. It wont be too bad, because the resistors can stay on the top of the pcb. I just hope that the heatsinks on the mosfets don't damage the power supply board, with the heat updraft onto the board. _

 

To aid ventilation you could drill a few holes in the PCB around each of the heatsinks.


----------



## amphead

Good idea Dcheming, I will probably do that.

 Anyone order any parts from tubeamparts on Ebay? He shows a California location, but ships from HK. So I had the part shipped priority mail and don't know if that is an avialable shipping method from China. 

  Quote:


  Originally Posted by *dcheming* /img/forum/go_quote.gif 
_To aid ventilation you could drill a few holes in the PCB around each of the heatsinks._


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_So I had the part shipped priority mail and don't know if that is an avialable shipping method from China. _

 

I don't think it is, but you can check around. Over at VT4C, he lists some way that he can ship items to the US:
V4TC Shipping Methods

 You might send a quick email to Chung at VT4C (chung@vt4c.com) and ask (even though he isn't sending these to you.) Might be good information for ya.


----------



## amphead

While awaiting more parts, I sanded and polished the cocobolo sides. Starting with 100/220/240/400/500/1200 and then 0000 steel wool. It is very smooth and starting to shine. Cocobolo sawdust is toxic. If you are cautious and wipe off the dust every once in awhile, you will be OK.


----------



## amphead

I will order the 370dax from angela.com on monday. Depending on how long heavy parts take from east to west coast, will determine how long it takes to finish my build.


----------



## bhjazz

Amphead - when you soldered the boards together and dropped the tubes in: how tall is the 6N6P? I'm shopping for a case! It looks like it might be around 3" or so from the bottom of the board to the tip of the tube...


----------



## amphead

Yeah, 3 inches just barely clears from the glass projection on the top of the tube to the base of the board. Good Luck!


----------



## bhjazz

Gah! Bummer. Okay, I'll have to consider a different case then, or hang those beauties out the top of a shorter one. 
 Thank you!


----------



## miky

Can someone compare DV 332 to Bijou?


----------



## amphead

Don't know who can help you on that one.

 Well, photoflash caps arrived 410uF 300v, and I am soldering on the leads, as these have a different style for the terminals. They have a knurled metal connection point that identifies it as the negative terminal. The 370DAX and EZ80, are on their way from angela.com and should be here in a week. Studying the wiring diagram carefully to make sure it is the one used with the 6DJ8 and 6N6P.


----------



## amphead

Also waiting on the large caps for the power supply, which are coming from HK. A different vendor than the one who supplied my output caps. Just finished installing the mosfets on the power supply board. I used 4-40 stainless screws/locking nuts, with the insulating pads and teflon washers. Another thing that I did, was to use about 12 inches of plumbers teflon tape carefully wound around the screws as electrical isolation from the heatsinks. It will withstand 320 degrees celsius or about 600 degrees farenheit, which is more than enough. It's not recommended to rely on the thin anodized coating on the heatsinks to electrically isolate the machine screws from them.


----------



## amphead

Only one item not ordered or installed, and that is the RK27 50K volume pot. Well I guess there are really 2 items, since I am going to install a push button latching ON/OFF switch. And then on to the wiring of the transformer to the power supply board and the test of that circuit first.

 This latching push button might look good on the front panel.


----------



## dBel84

yeah - that looks sweet, looking forward to the unveiling  ..dB


----------



## Mazuki

Quote:







 

Be careful with those, I've heard of them breaking after a couple of months.


----------



## amphead

Quote:


  Originally Posted by *Mazuki* /img/forum/go_quote.gif 
_Be careful with those, I've heard of them breaking after a couple of months._

 

Thanks, thats good to know because I didn't order them yet. I was suspicious of the low price. $19.95 for three. I want to find a latching pushbutton that is rugged and has 100,000 or more cycles. Preferably soft spring style.


----------



## Nebby

I picked up some of the Bulgin latched switches, and they were roughly $20 eah 
	

	
	
		
		

		
			





 On the other hand they are electrically rated for 100,000 cycles minimum


----------



## Mazuki

Quote:


 Thanks, thats good to know because I didn't order them yet. I was suspicious of the low price. $19.95 for three. I want to find a latching pushbutton that is rugged and has 100,000 or more cycles. Preferably soft spring style.  
 

The spring is soft indeed, but definitely not rated for 100,000 cycles. On the other hand, they're so cheap and are sold in triplets. It won't hurt to use them. Just be prepared to install a new one after a year or so. 

 There's also some that are illuminated. They're a great way to combine LED and switch.


----------



## fordgtlover

Just received my kit from Jeff - looks great. 

 Jeff's does a brilliant job with his kits.

 Now to get the transformer and I'm away.. woohoo


----------



## tobias_svensk

Get one of these (Bulgin) they look awesome, about €20 in sweden so they aren't cheep.. but but.. 
	

	
	
		
		

		
		
	


	



http://www.elfa.se/pdf/35/03507225.pdf


----------



## Nebby

Those look really nice, like a led ring version of the one I got. Wonder if there's a stateside source for them


----------



## tobias_svensk

Yeah, really nice.

 Last picture was my own switch that hasn't been installed yet, but I was thinking of making this circuit:
Soft Switch

 And on that site you can se how it looks when it's "on"





 Cheers


----------



## Nebby

That's the only part that I'm not too thrilled about. The need for a relay based backend to use the momentary push button convinced me to pick up the latching push button. On the other hand, that soft switch pcb looks very convenient. I wonder how much does it cost to get pcb's made up.


----------



## amphead

Here is the mouser part number for a Bulgin 18mm blue ring illuminated latching switch in stainless steel for $13.90
 I have one coming in 2 days along with a neutrik phone plug. The only drawback being 18mm, which is not as large as I wanted. But it's good for 200,000 mechanical cycles and 30,000 electrical cycles. This means that it will turn the circuit on and off 30,000 times and then you can push the button 170,000 times if you want after it stops working. he he 

 117-MP0045/1E2BL012


----------



## Nebby

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Here is the mouser part number for a Bulgin 18mm blue ring illuminated latching switch in stainless steel for $13.90
 I have one coming in 2 days along with a neutrik phone plug. The only drawback being 18mm, which is not as large as I wanted. But it's good for 200,000 mechanical cycles and 30,000 electrical cycles. This means that it will turn the circuit on and off 30,000 times and then you can push the button 170,000 times if you want after it stops working. he he 

 117-MP0045/1E2BL012_

 

Thanks for the part number!


----------



## amphead

Have 100% of the parts on their way. Sprayed my Cocobolo sides with shellac. 3 coats of the Shellac. Tommorrow, 3 coats of Cellulose Lacquer. This is a hard and mirror shiny finish when done. Cocobolo is an oily wood therefore always spray Shellac before Lacquer to get good adhesion.


----------



## bhjazz

<-- drooling. 

 Coolness, amphead. And a woodworkers education tonight to boot. Thanks! 

 I've been working on getting Alien dac parts and have stupidly neglected my kit. What am I thinking?


----------



## amphead

Thanks Bhjazz, are you trying to get the Bijou done in time for the Seattle meet? That should get a good turnout. If I could swing it, I would visit family there and go to the show, but alas it just is not in the cards.


----------



## Nebby

please post photos when you're done, I've been planning to use wood for enclosures for my next few projects and wouldn't mind seeing how yours turn out


----------



## amphead

Absolutely Nebby, I will be posting right after buffing out the Lacquer coat, even before mounting more parts. Thanks


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Thanks Bhjazz, are you trying to get the Bijou done in time for the Seattle meet? That should get a good turnout. If I could swing it, I would visit family there and go to the show, but alas it just is not in the cards. _

 

Nope. I actually just got my Ck2III done a couple of weeks ago so that'll be my debut piece for the show. Would I like to bring both? Hell yeah! I just don't think I could get this one done in time. So much to build, so little time. 

 Family up here? Excellent. Just know you are always welcome to attend a meet up here. Any time!


----------



## amphead

All boards populated and Cocobolo received 3 coats of Lacquer today. I have to wait about 3 days before I start polishing the finish up to a mirror. 370DAX, EZ80, Illuminated power button, and locking input jack arrive tommorrow, just leaving the RK27 50K to arrive in a few more days.


----------



## dBel84

That is gorgeous wood, nicely done ..dB


----------



## amphead

Thanks dB, the hardest part when working with lacquer, is to keep from trying to polish the finish prematurely. If you work too soon on it, you get some slightly sticky goo under the top of the finish. If you wait at least 3 days the solvent has evaporated enough from the lacquer, that it is hard. Then you start with 600 grit paper and wet sand up to 1200 paper. This is followed by Meguiars Mirror Glaze used on automotive paint. Then this is just carefully buffed by hand up to a mirror sheen with a soft cotton cloth. This is the way guitars are often finished, which is my other hobby.


----------



## amphead

Installed the 370DAX on to the top plate. Now the amp is getting heavy.  Will wire up the Illuminated switch tommorrow and install the iec plug on the back of the case. The led in the illuminated switch, requires a 12 volt powers source.


----------



## Listen2this1

Here are some other options for the switches.
3,Stainless DPDT OFF/ON White Led Car switch 12V W22ZE - eBay (item 120228264165 end time Mar-07-08 20:41:50 PST)


----------



## amphead

Nice switch Listen2this1.

 Today I mounted the iec plug by cutting a rectangular opening in the back panel. Then I brought the front panel up to a mirror finish 1 day early. I couldn't wait to see it and it came out with a 100% mirror finish after wet sanding up to 1200 paper and then repeatedly polishing with Meguiars Mirror Glaze, with a cotton cloth. I will post a pic after the front panel is populated.


----------



## Mazuki

amphead: it looks to me like your output film caps are metallised polyester (MKT). I would suggest at least metallised polypropylene (MKP), paper in oil (PIO), or even Teflon. 

 For the price, some Wima or Vishay Roederstein MKP would be best.


----------



## amphead

Yeah, they are Vishay Roederstein MKT. I will replace those with something better, when I can. I misread the description when those were ordered from Mouser.

 Today I installed the illuminated power switch and should have the locking input jack installed tonight.


----------



## amphead

Purchased the Wima Polypropylene caps MKP and they should be here soon. Polyester MKT just won't sound good. 
 Also I ordered 140 feet of black 22awg teflon 600v milspec wire, to go with the 40 feet of green that I currently have. That should be here soon too. Last night I had a rough time installing the Neutrik jack on the front panel. I had not measured correctly, so that I had to file down my aircraft aluminum frame in that spot. After a frustrating time, the jack finally was flush to the front panel. So this is a pic of the amp now.


----------



## jamess71

Very nice work amphead. 
	

	
	
		
		

		
		
	


	




 Question? I just got my kit from Jeff and I'm wondering what else I need? I'm pretty sure a transformer. Also a case. Anything else? Anybody have part #'s for mouser of digikey? Thanks

 James


----------



## willisv

For a transformer, you could purchase a 270DAX from Angela Instruments. 

 You will also need a set of rca jacks, a 1/4" headphone jack (Neutrik makes a nice one), mounting hardware for the pcb boards and some suitable wire. I would also recommend an IEC power jack and switch as well as a couple of knobs for the volume and NFB pots. If you use the IEC jack then you can use any home computer power supply cord to plug it in.

 I used a terminal strip to wire mine but Alex has instructions on his site to wire the Bijou without one.


----------



## Mazuki

Amphead, you've put so much effort into the amp case already, why not buy a forstner bit and counter-bore those two knobs. It would really step up the aesthetics another notch.


----------



## amphead

You must be telepathic Mazuki, because the countersunk knobs is exactly what I had in mind. I want to hear the Bijou fairly soon though, so I will complete the build first. Also, if you notice the top edge of the amp has not been worked on yet, and there will be a facade to clean those edges visually. I have worked out a top design for the amp, but will do that when the amp is fully functional. thanks


----------



## jamess71

Quote:


  Originally Posted by *willisv* /img/forum/go_quote.gif 
_For a transformer, you could purchase a 270DAX from Angela Instruments. 

 You will also need a set of rca jacks, a 1/4" headphone jack (Neutrik makes a nice one), mounting hardware for the pcb boards and some suitable wire. I would also recommend an IEC power jack and switch as well as a couple of knobs for the volume and NFB pots. If you use the IEC jack then you can use any home computer power supply cord to plug it in.

 I used a terminal strip to wire mine but Alex has instructions on his site to wire the Bijou without one._

 

thanks willisv, I have jacks, knobs, plenty of navships wire. 
	

	
	
		
		

		
		
	


	




 I'll need to order mounting hardware & case, power jack, and transformer. 

 The 270DAX is the recommended power supply? This is a hammond right?

 How about a case's Any rec's on them? 


 Thanks again. 
 James


----------



## amphead

I will leave it for some others to recommend a case, but if you are willing to spend another $15.00, you could go for the 370DAX. However the 270DAX works fine. Purchase either from angela.com

 Well, I countersunk one of the knobs about 3/8 inch today. It looks very nice. I am going to start on the second knob this evening. Because I have a small craftsmen drill press, I can't use a forstner bit. So......how did I do it? I mounted a shaft onto my aluminum knob and the shaft fits the hole on the front panel without any wiggle room. I epoxied some 36 grit sandpaper to the bottom of the knob after sliding it on a hole provided in the paper and onto the shaft. After the epoxy dried I repeatedly ground the knob around and around,until a 1/16 inch deep round groove was worn in. This provides a precise hole size around the knobs. Then I took my woodcarving tool and chipped out the wood to create a 3/8 inch deep recess. Then I followed again with the sandpaper knob and ground the finish smooth, at the 3/8 inch depth. I then peeled off the sandpaper and cleaned the knob and put it on the front panel. It looks really good. Can you say tendonitis?


----------



## amphead

The Wima polypropylene caps arrived today, and I will remove the MKT caps and replace those with the MKP tonight. Last night I finished recessing the second knob and they both look good. The other task is to mount the pots on to my shaft extensions. The shafts on the pots were 1 and 1/4 inches too short in my situation with a thick chassis.


----------



## amphead

Wimas were installed, after a short fight with the MKT polyester caps. I bend my leads onto the board, so removing is a little more difficult. Now to get my RCA jacks. Just the cheap ones for now, but possibly WBT in the future. Waiting on 140 feet of silver plated teflon 22awg, which will be here in a couple of days.


----------



## Hudson

Anyone in the uk building a bijou? I'm having trouble sourcing a suitable traffo from a uk supplier, can anyone point me in the right direction please.
 Cheers.


----------



## amphead

I'm not sure what to recommend for the tranny, but I wouldn't be surprised if you end up ordering the 370DAX from angela.com, which has the primaries voltage used in the UK. You would be looking at $59.00 for the transformer and about $30.00 shipping to the UK. With the dollar to pound conversion, it might work out OK. 

 Tonight, I cut some pass-throughs into the top plate for wiring. This build will be a top-mount design. Please no torches and pitchforks, I know the bottom mount design is a very good solution as well.


----------



## dBel84

Quote:


  Originally Posted by *Hudson* /img/forum/go_quote.gif 
_Anyone in the uk building a bijou? I'm having trouble sourcing a suitable traffo from a uk supplier, can anyone point me in the right direction please.
 Cheers._

 

SOWTER will do one for you , but it will cost more than either the r-core from HK or the hammond. 


 No pitchforks allowed here amphead 
	

	
	
		
		

		
			





 ..dB


----------



## Mazuki

I would go with the R-core from Hong Kong. It's the cheapest and doesn't run too bad either.


----------



## Hudson

Ok thanks for the replies everyone, I shall have a good search over the weekend. I did check out Sowter, but yeah, they're pricey, I'll probbly ship something in from abroad.
 Cheers.


----------



## amphead

Today, I created a 12 volt dc power supply on perf board, for the Bulgin latching illuminated switch. I used a Radio Shack 12vac transformer, a full wave bridge and a 680 ohm dropping resistor for the illuminated/led on the switch.(Thats overkill, but Bulgin switches often lose their built-in leds due to some mistake.) I installed the power supply underneath and wired it to the iec jack. I thought about making it illuminate only when the power button is on, but decided to have it illuminated anytime the iec is plugged in. I installed and wired up the Bulgin switch. Nice blue ring glow.  Other than the heater leds , there will be some led indication of the power-on for the amplifier, later in the design and powered off of the 12vdc power supply. High Voltage/transformer test tommorrow.


----------



## amphead

Received the shipment of 22awg teflon mil-spec wire. Even though its rated for 600v, it is as skinny as 24awg because the insulation is so thin. It shoud be easy to work with. Currently, I am wiring up the transformer and fuse/holder to the iec jack, with 20awg teflon. Secondaries check to follow.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Today, I created a 12 volt dc power supply on perf board, for the Bulgin latching illuminated switch. I used a Radio Shack 12vac transformer, a full wave bridge and a 680 ohm dropping resistor for the illuminated/led on the switch._

 

Brilliant! I was wondering where you were going to extract 12 v from. Coolio, man!


----------



## da_burl

I just built up my boards, and my casework is in progress. I am pretty new to woodworking, so my prototype is "Select Pine" 1x6 from Home Depot 
	

	
	
		
		

		
		
	


	




 I will probably just sand it, put a round edge on the butt joints, and paint it or use some cheap veneer or laminate for now. I "think" I could transfer it to another case pretty easily (transferring, not building the case) 
	

	
	
		
		

		
		
	


	



 I am going to try to use a router to cut recesses for the IEC input jack and the power switch on the back panel, but if I screw that up, I'll probably cut a larger rectangle out and put an aluminum panel on the back.
 I can't quite finish because I accidentally ordered 47uF 250v for C6 in the power supply. I was downsizing the voltage rating on some of the caps based on the "other" thread over at that other place, but this one looks like it really does need to be 450v. I think I could leave it out just to test it, but I am just not real sure of the impact of doing this, so I think I'll just wait it out. 
 I used PRP resistors exclusively in the amp boards, but had to get a few V/D's on the power supply.
 I am also thinking of having the output electrolytic and film bypass caps mounted off the board for experimentation. Got some Sonicap Gen II's to try there first.
 It's hard to wait, but I know it will turn out better in the long run if I don't try to rush it now 
	

	
	
		
		

		
		
	


	




 I've got a few other things to do anyway on the case and I could start the wiring up between boards and xformer too. Without power of course.


----------



## amphead

Good to know Da-burl! Keep us up to date on your progress.

 After carefully isolating all unused leads on the transformer, I checked for secondary voltage with the Bulgin switch doing the honors. Everthing is close to what would be expected for floating secondaries. 284-0-284vac and 6.5vac. The primary winding is wired per angela.com suggestion for 370DAX at 120vac, with black and blue wires combined on one leg and brown and white wires combined on the other leg. The power supply should be able to provide 250v B+ from this, as opposed to wiring the primary for 110vac.


----------



## amphead

Although, it isn't necessary to use a terminal strip in this design, I decided to add one for the 260-0-260vac and the 63vac. It gives the wiring a tidy appearance. I also added wire-tie mounts and ties. I clipped/isolated the unused transformer leads. Power supply board to be energized soon.


----------



## exphy

is it just me or does glassjar audio not sell kits anymore?


----------



## Jrossel

Quote:


  Originally Posted by *exphy* /img/forum/go_quote.gif 
_is it just me or does glassjar audio not sell kits anymore?_

 

Still making kits, just out of capacitors (and just got a shipment in now). Please E-mail, or contact me through my website.

 JR


----------



## amphead

Alright more Bijous! I decided to finish mounting the RK27 volume pot today, before going for the power supply test. The pot is mounted on perfboard like Mazuki has done but due to my aircraft aluminum frame sticking out 1 inch, I have to screw it into an oak block that is attached to the frame. A bit of a headache, but will work fine, when all is said and done. Seems like the last 5% of the build goes at a snails pace, but that's just me being overly cautious. I am also going to pull the power supply board off of the chassis again and thoroughly clean the botton with alcohol and triple check everything. The only thing that has me concerned are the mosfets, which deal with lots of High Voltage. No arcy-sparky.


----------



## Mazuki

I think you'll be fine. The Bijou is was one of the easier builds I've done. Just make sure you steer clear of the metal top of the blue Xicon 47uF power supply cap. It carries live voltages.


----------



## da_burl

Quote:


  Originally Posted by *Mazuki* /img/forum/go_quote.gif 
_I think you'll be fine. The Bijou is was one of the easier builds I've done. Just make sure you steer clear of the metal top of the blue Xicon 47uF power supply cap. It carries live voltages._

 

Not that I was planning on laying my elbow on them, but that is certainly good to know 
	

	
	
		
		

		
			





 While waiting for my package from Digikey, I cut, twisted, and mock laid out my wiring. Looks like I'm going to be able to do it pretty much per runeight's original instructions, i.e. no extra terminal strips, just a big bolt for the star ground. The particular teflon wire I have seems to "mold" pretty good, I twisted the pairs and bent it to shape. I ordered some of those cool tie-wrap screw mount thingies and ring terminals from Parts Express too. So, looks like it will still be a few days before I can power mine up.
 Probably should have been out in the garage practicing my woodworking instead. I'm still a bit apprehensive about cutting out the square hole for the IEC inlet. But I can always cut another panel I guess. I got an extra board just in case. I haven't glued them yet, just some screws. I have to be able to remove my front panel because my plan is to have a sheet of perforated aluminum slide into a thin dado groove on the top, and the regular aluminum bottom chassis slides in as well. So I think I'll put a couple of blocks in the inside front and use some sharp looking screws, maybe those Kreg square drive pocket screws with integrated washers. Also eyeing those screw-in threaded inserts and then I could use bolts.


----------



## amphead

Thanks for the heads-up Mazuki! Yeah, I treat the whole board area/components as though they are going to bite. Something certainly will if it isn't given the proper consideration. You should not fear the amplifier, but you should think carefully about what you are doing before putting hands on or near anything. Check with the meter and discharge caps as neccessary. Well, I am going to wire the power supply board to the secondaries now and test. :-| Edit: looks like you are getting a nice build together Da_burl!


----------



## amphead

So........I wired up ground wire to the power supply board and then to the star ground point, then 260-0-260vac and 6.3vac. Installed a 2 watt 100k resistor across the output points on the ps board. Then I clipped my meter leads across the resistor and set it to 1000vdc. Powered on with the Bulgin switch doing the honors and.........EZ80 heater lit up, but 8vdc reading on the meter. After a quick expletive, I adjusted P1 and walla voltage climbs to 276 volts and so I back the pot down to 250 volts and it holds steady for 5 minutes and then I power down. Thinking about the mosfets was making me nervous, when I didn't see High Voltage immediately. But you won't get HV with the trim pot fully CCW. So now to finish doing the volume and NFB pot mounting on the chassis. So far things are going well. 

 Edit: Da_burl, I would drill a large enough hole in the place where the iec jack goes and then take a medium square file and some elbow grease to cut in your rectangular mounting point. It's almost fool-proof.


----------



## da_burl

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_So........I wired up ground wire to the power supply board and then to the star ground point, then 260-0-260vac and 6.3vac. Installed a 2 watt 100k resistor across the output points on the ps board. Then I clipped my meter leads across the resistor and set it to 1000vdc. Powered on with the Bulgin switch doing the honors and.........EZ80 heater lit up, but 8vdc reading on the meter. After a quick expletive, I adjusted P1 and walla voltage climbs to 276 volts and so I back the pot down to 250 volts and it holds steady for 5 minutes and then I power down. Thinking about the mosfets was making me nervous, when I didn't see High Voltage immediately. But you won't get HV with the trim pot fully CCW. So now to finish doing the volume and NFB pot mounting on the chassis. So far things are going well. 

 Edit: Da_burl, I would drill a large enough hole in the place where the iec jack goes and then take a medium square file and some elbow grease to cut in your rectangular mounting point. It's almost fool-proof._

 



 That's what I was going to do, but then I got the crazy idea to try to flush mount it. So I ordered the screw mount ones with the triangular ears. I would actually need a square hole for the body and a recessed area on the outside surface for the mounting ears. You're right, I can probably do most of it with a drill and a file, but I think I would have to use a router or a good old chisel for the recess. 
 I have plenty of scrap pieces to practice on, so I might give it a try. If it doesn't work out too well, I will just flat mount it, with the ears on the surface of the panel. It will be on the back at least 
	

	
	
		
		

		
		
	


	




 You probably know how it is to obsess on some little detail that has nothing to do with the actual functionality or sound 
	

	
	
		
		

		
		
	


	




 On another note, my ebay pots THESE and THESE
 are on their way from Hong Kong as we speak! I thought I'd give them a try before laying out real cash for a real DACT or Goldpoint or something. Kinda hoping the SMD ladder pot works out ok, it looks kinda cool.


----------



## ericj

Quote:


  Originally Posted by *da_burl* /img/forum/go_quote.gif 
_On another note, my ebay pots THESE and THESE
 are on their way from Hong Kong as we speak! I thought I'd give them a try before laying out real cash for a real DACT or Goldpoint or something. Kinda hoping the SMD ladder pot works out ok, it looks kinda cool._

 

You know that first one isn't really made by Alps, right? 

 I have a couple of the 'fake alps' 100k attenuators and while they work, I don't really recommend them unless you like to hear a loud snap every time you turn the knob. That can be minimized by disassembling the pot and cleaning everything with deoxit or similar, and then applying a good layer of silicone grease. But it's annoying, and it's just a series attenuator anyway.


----------



## da_burl

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_You know that first one isn't really made by Alps, right? 

 I have a couple of the 'fake alps' 100k attenuators and while they work, I don't really recommend them unless you like to hear a loud snap every time you turn the knob. That can be minimized by disassembling the pot and cleaning everything with deoxit or similar, and then applying a good layer of silicone grease. But it's annoying, and it's just a series attenuator anyway._

 

Yeah, I kinda figured, I remember an old discussion about them. 

 My first try was getting four of THESE . Spent about nine hrs. putting one together, and although I carefully tested the first step and the next two or so, after that, I went all the way through 3/4 of the way or so before I measured it again. Seems that I must have applied too much heat or something, one whole switch bank is open now, so it's fubar'ed. Haven't taken it apart yet, but I might as well someday to see what I can see. I think I'll start another one and leave it there and put one step and measure each day until it's finished. 
	

	
	
		
		

		
		
	


	




 If I prescribed to the time is money theory, these things are so not worth it!!!
 By the time I get all these different fakes, I probably could have just gotten a real one, but I'm a cheap bastid too


----------



## ericj

Quote:


  Originally Posted by *da_burl* /img/forum/go_quote.gif 
_Yeah, I kinda figured, I remember an old discussion about them. 

 My first try was getting four of THESE ._

 

Oh man, i wish those had been cheap and widely available 2.5 years ago. Back then, that kit was a lot more expensive. 

 I got a wild hair and bought the 23 position 4 pole Alps rotary switch from triode electronics and bought resistors for it from mouser. Modified it so that it would straddle regular perfboard. 

 I spent at least $60 on the whole affair, including shipping and 10-piece minimums on 6-cent resistors. And the time when i lost one of the values and had to order another bag of 10 from mouser all by itself with $5 shipping. And then discovered after i got that value that i'd forgotten to order another value. uuugh. 

 At the time i meant to put it in my M3, which still lives in a cardboard box (I never settled on an enclosure for it). 

 I'm using it in my Bijou. It's huge. I feel like a moron for ever building it, but using it is the least worst option at this point. 

 In case not everybody is following the bijou thread at HW, here's some pics from a few days ago. At this point the last thing to do is star ground. I think I've decided where to put it. 










 The plan is to paint the mesh flat black and the front, back, and bottom panels in a semi-gloss or satin black. I'll need to do some work on the metal first, as the enclosure is an old Dukane PA speaker enclosure from a school hallway or something.


----------



## bhjazz

Ericj - as I said on Headwize: amazingly original case! So much more original than what I had planned. Looks like a keeper! Never mind about the Alps rotary, I bet it'll be great with the Bijou. 

 Congrats!


----------



## amphead

Nice work EricJ! Very impressive design. The stainless front is impressive and it would also look good with an exotic hardwood veneer, epoxied to the front panel. Either way, it really kicks up the Bijou design a notch. How does it sound, and what phones are you using?

 I am attaching my volume and NFB pots to the chassis tonight.


----------



## ericj

That's stamped aluminum actually. And they didn't bother to finish the edges, either, so I'm going to have to file them down before painting. 

 I haven't finished building it so I'm not sure how it sounds. I'm using 6n1p-ev and 6n6p, fwiw. And i have ever so many 'phones to choose from, so I'm not sure where I'll start with it. 

 All i have left is star ground. I could have finished it tonight but i can't find my box of lugs. If i still can't find it tomorrow I'll just buy more. I'm also missing some of the hardware i need to hold the enclosure together - used to be held together with rivets. Using speednuts and screws, except i have the wrong screws, and didn't buy enough speednuts.


----------



## bhjazz

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_And they didn't bother to finish the edges, either, so I'm going to have to file them down before painting._

 

Nonsense! Sharpen them up and make a cigar cutter out of 'em.


----------



## amphead

EricJ, if I had a slew of headphones to choose, as you do, I would go for your best high impedance set. Higher impedance phones require less NFB = Better Sound.  Edit: My K701s at 64 ohms will require a good bit of NFB.


----------



## amphead

Still didn't install the volume and NFB pots. Changed plans and wired the right channel amp heaters up. Powered up with meter across ps output. Heater right channel led lights up green. More importantly right channel tubes heaters lit up. PS voltage was 252vdc, so I adj. for 250vdc. Still on schedule, as slow as it may be.


----------



## runeight

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_That's stamped aluminum actually. And they didn't bother to finish the edges, either, so I'm going to have to file them down before painting. 

 I haven't finished building it so I'm not sure how it sounds. I'm using 6n1p-ev and 6n6p, fwiw. And i have ever so many 'phones to choose from, so I'm not sure where I'll start with it. 

 All i have left is star ground. I could have finished it tonight but i can't find my box of lugs. If i still can't find it tomorrow I'll just buy more. I'm also missing some of the hardware i need to hold the enclosure together - used to be held together with rivets. Using speednuts and screws, except i have the wrong screws, and didn't buy enough speednuts._

 

ericj, don't forget that you need to change the cathode resistor (R2) for the 6N1P. Values are listed in the Tweaks section on the website.


----------



## ericj

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_ericj, don't forget that you need to change the cathode resistor (R2) for the 6N1P. Values are listed in the Tweaks section on the website._

 

Yeah, i did observe that necessity.


----------



## da_burl

My Power Supply lives!!! (Yes, I know the Gold banana plugs on the meter should not be touched or licked at this particular time).







 Pardon the casework, I wanted to do a full mockup in pine so I can learn everything I did wrong so I won't do it when I invest in some hardwood 
	

	
	
		
		

		
		
	


	




 Amphead, I ended up investing in a hand <gasp> coping saw, it worked wonders for the square cutouts, along with the file for finishing it up. Next on my list is some calipers, instead of trying to eyeball and trace the part.

 Parts Express parts didn't arrive today, so I am still waiting to get the cable arranging supplies before doing too much more. I guess I could mount the other two boards and stare at it


----------



## amphead

You could also use a veneer over pine, but the thickness of the chassis can be a pain for mounting pots. But in your case without an aluminum frame, Mazukis suggestion of countersunk knobs can get the pots mounted the easy/usual way. Happy to hear your PS was working.  I will wire up the left channel heaters today and get the volume pot mounted.


----------



## Mazuki

Wow da_burl you went the Panasonic filter caps. Good choice!


----------



## amphead

Wired up left channel heaters, set the meter up across the PS load resistor. Powered-on and .............#&#&@&$#. No High Voltage, heaters....nothin. Immediately powered down, and checked to see if the fuse was blown. No, fuse was good, so I did a continuity check from transformer hot leads to the PS board connections. Checked out good. Imagined the mosfets had failed, which they had not. Symptoms did not match the fix, because I released the wires on the terminal block and then re-inserted and tightened down on each connection. Powered-on again and........HV good at 249vdc, all tubes heaters on and 2 green leds lit up for the heaters. Very beautiful sight!


----------



## amphead

The saga continues.......powered-on later and no HV. Found 2 possible causes. The load resistor leads did not seem tight enough in the connector. Soldered wires onto the resistor and reinstalled it. Also remembering what Runeight said over on Headwize about soldering the crimp connectors on the star ground was gnawing at me, so I soldered the connectors and re-installed those. HV returns, so I will move onto the volume and NFB pot installations.


----------



## amphead

Cutting the oak block for mounting the volume pot and soldering the crimp connectors on the terminal block for 260-0-260vac.


----------



## zincman

Interesting


----------



## amphead

Finished installing the volume pot/knob assembly onto the oak block on the chassis. Cut a piece of lexan to mount the perfboard on, to allow for a bolt adjustment of the angle of the coupling shaft. A coupling was fashioned out of a 1 and 1/4 inch, 3/8 inch diameter vinyl tubing, onto 1/4 inch brass tubing. This allows for easy disassembly if neccessary, and an unintended benefit is a non-conductive isolation of the knob from the pot. This is a strong and smooth volume manipulation for the amp. Very tedious, but well worth the hassle, that I went through. Only neccessary when the volume pot needs an extension shaft, and can not be mounted directly to the front panel. The NFB pot mounting, and connections to the RCA Jacks are all thats left for the amp board tests and if I'm lucky..........listening.


----------



## dBel84

almost there 
	

	
	
		
		

		
		
	


	




 ..dB


----------



## da_burl

I had a busy weekend of non-DIY activity. Also, my parts still did not arrive from PE yet. So I spent some more time laying out things and discovered two things:
 Three 20 G wires do NOT fit very well at all into the terminal strips on the board, so I am going to have to use a terminal strip to distribute the heater wiring after all. (Most everybody seems to have already figured this out) 
	

	
	
		
		

		
		
	


	



 It's a PIA mounting jacks and pots on 3/4" stock (I knew it but didn't think it would be quite this bad). To route or drill out the area on the other side I am getting the remaining wood so thin that is doesn't seem substantial enough anymore) I am now going to have an aluminum or plexiglass panel on the front and back. Maybe small ones on the sides too if the plexiglass works out. A see through tube amp) 
	

	
	
		
		

		
		
	


	




 Mazuki: Some masochistic streak in me made me just order the boards from Jeff, and then spend several hours coming up with my own BOM. This kinda started because I wanted to use red turds (PRP) instead of brown turds (Dale) for resistors this time 
	

	
	
		
		

		
		
	


	




 Plus I also already have a collection of pots, jacks, and had already ordered some tubes. I hope the Panasonic caps work out ok, I bought some Nichicon and Panasonics in the 250v rating for the coupling caps on the amp boards to do some comparisons. Might even try the photoflash cap option someday !! 

 Amphead, good deal on you progress, of course we are interested in your first listening impressions!


----------



## regal

What I have been racking my brains over is how to air-wire the alps pot. This is a PCB pot and I can't figure out how people are air-wiring this thing.

 On the other forum I asked and was told "its all very basic just etch a PCB here's the cad file." IMO this should have been included in the kit, unless I am completely missing something. Is there some sort of a femal pin that mates with each pin of the ALPS ?


----------



## rhester

It is easy to air wire. Leads from rca inputs are soldered directly onto the input side of the pot and then outputs are soldered to the pot and run to each channel. Worked for me any way.


----------



## regal

Quote:


  Originally Posted by *rhester* /img/forum/go_quote.gif 
_It is easy to air wire. Leads from rca inputs are soldered directly onto the input side of the pot and then outputs are soldered to the pot and run to each channel. Worked for me any way._

 

But what technique did you use to get the wire to solder onto the pins ?


----------



## amphead

Regal, all you need is a set of helping hands, from your local electronics store. Some 22 gauge wire is bent over on the end and you put the wire into the alligator clip of the helping hands and the pot shaft is held with the other alligator clip. Then you push the alligator clips close to each other until the wire is onto the soldering point. Push the bent over wire onto the pin on the pot. Now both of your hands are free to solder. Hope this helps.


----------



## dBel84

Have a look at Tangents illustration







 The wiper would be the pot output and the actual input for the amp circuit..dB

 edit - delayed post - sorry

 just solder the wires directly to the pins and heat shrink the join to isolate them


----------



## da_burl

Regal, the part you might be missing is the tinning part. You put a thin layer of solder on each pot lead, and then heat and put solder on each stripped wire end. This is called tinning the leads. Then arrange the pot leads and wire with something that holds them together. This can be a helping hand or clamp to hold the pot. If you have good steady hands, you can hold the wire with a pair of pliers or tweezers, maybe rest your hand on the tabletop to stabilize it. You just don't want to have the wire moving or wiggling while the solder resolidifies , this will result in a cold solder joint. Then you reheat them both together and the solder flows together and joins the pot leads to the wire. Sometimes it's not even necessary to put more solder on while doing this, but usually I do. Don't forget to put the heat shrink on first and slide it down the wire away from the heat. I think there are some real clear pictures of all this in the "build your own interconnects" thread at the top here.
 There's another way which is the way I was taught in a soldering class believe it or not 
	

	
	
		
		

		
		
	


	




 They preached a good physical connection and not using solder to actually hold the parts together. Strip and tin the wire a little longer than you originally would. Bend the end of the wire into a small U shape, then bend it 90 degrees so its "horizontal" to the wire, and squeeze this into the pot lead with the pliers and squeeze it down so it holds. Then wrap the rest if the wire almost down to the insulation around the pot lead in a spiral. It's supposed to stay there by itself (a good physical connection) Then solder the whole thing 
	

	
	
		
		

		
		
	


	




 You have to practice it a bit to get the length right and not mangle the tinned lead too bad 
	

	
	
		
		

		
		
	


	



 On those Alps pots, you'd have to do this whole operation kind of lightly, because the pot leads are not real strong. That's the reason some people are making pc boards for it, to support the leads and give it an easier place to solder to. And you don't want to overheat the pot itself either, it could destroy the resistive element inside.


----------



## dcheming

Here's some pics of my air-wired ALPS pot using 24ga solid core:


----------



## ericj

I'm using CDE capacitors for the output on my Bijou, and they sound just fine to me, but I'm curious - which photoflash caps are folks using, and where are they getting them? 

 I mean, pretty much all capacitor makers make some photoflash parts, and their rated lifespan ranges from 10,000 flashes to 100,000 flashes. And i don't really see any on mouser, etc.


----------



## Mazuki

Quote:


 which photoflash caps are folks using, and where are they getting them? 
 

eBay, there's a pretty large selection.


----------



## regal

Thanks for the info on air-wiring the ALPS, I too was always taught you need a mechanical connection and not to rely on solder. I guess an amp is an exception since it isn't mobile.


----------



## amphead

Ericj, or anyone who wants to buy the same caps I used can find it here.

RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 360025524313 end time Apr-19-08 15:31:29 PDT)

 Installed the NFB pot similarly to the volume pot and it is sturdy and smooth. Now, I'm wiring the volume, NFB pots and the rca jacks.


----------



## funch

Now, you know someone had to build this, right?
 Presenting the "Blue Bijou".


























 Kit from Jeff Rossell (thanks, Jeff). Front panel from FPE. First listen was very impressive. Tube dampers are definitely on the menu. Dead quiet otherwise. Worth building, IMHO.


----------



## regal

What are the thoughts of using the Solen 330 uF caps for the output w/ 50 ohm headphones?

 I know with 330 uF there will be some phase distortion with 50 ohm headphones, but would the benefit of a film cap outweigh this ?


----------



## amphead

I would not recommend 330uF. You need at least 400uF to have a good bass response. Larger would be even better, to a point. If you go too large, the upper frequency response will suffer. 50 ohm headphones will require more negative feedback to get enough volume.

 So................wired up the amp boards for High Voltage, and it measured 247vdc, so I adjusted for 250vdc. The smell of a warm amp, and without any component failures. Turned the volume up and listened for music. Its Alive!  After listening for an hour and a half, I could hear the gradual break-in of the tubes and caps. Excellent soundstage and nice separation of the instruments. Vocals are warm and drums, cymbals really shine. Bass extends deeeep. I am using less than a quarter turn of the NFB knob. This seems to work best with my K701s. More breakin time tommorrow. Next I will finish the surround for the top mounted boards.


----------



## da_burl

Congrats, Amphead!!

 Work keeps getting in the way of me finishing mine 
	

	
	
		
		

		
		
	


	




 Never thought I'd say this (ever) 
	

	
	
		
		

		
		
	


	




, but I am heading down to Radio Shack <gasp> to get those white "Euro" terminal strips this afternoon, and my Hong Kong pots and attenuators are waiting for me at the Post Office. So I feel I might be listening to mine fairly soon as well! Won't be too pretty yet, but I think it will make music.


----------



## naamanf

I have had the boards built and awaiting a case for about a month now. Have yet to find a case I like. In the meantime I think I am going to just put it in a ammo can for the time being.


----------



## da_burl

Look out ericj, I just got back from the Thrift Store 
	

	
	
		
		

		
		
	


	








 It's a Bionaire Air Filter 
	

	
	
		
		

		
		
	


	




 It's probably not 100% ideal, but I just couldn't resist. I don't think the grille is metal after all, more like perforated plastic. But it actually works pretty good as an air filter. Would probably be pretty hard to remove enough of the innards to make room. And then there's the issue of the controls on one end and the bottom with rubber feet on the other. If I ever end up actually using it, I will probably just use the curved plastic grill.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Its Alive! 
	

	
	
		
		

		
			



_

 

Excellent! Glad things are all coming together now, it's working, and it's got that nice warm up fragrance....ahhhh!

  Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_Have yet to find a case I like._

 

I'm on the same place. But with the Seattle Meet over now, I'll be able to spen more time getting the final parts off of the "need it" list. 


 BTW: This is post 1000 for me! Woo! I'm on the "Supremus by Summer™" program now!


----------



## kvant

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_What are the thoughts of using the Solen 330 uF caps for the output w/ 50 ohm headphones?_

 

 Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I would not recommend 330uF. You need at least 400uF to have a good bass response._

 

I believe there is quite a few people who use 470uF with 32 ohm phones. I am among them and I wouldn't say that bass suffers. Now, the equivalent of 470uF into 32 ohm is 470*32/50=301uF, so that my conclusion would be that 330uF should be fine. You can try to experiment with some 330uF electrolytic there and commit to the big expensive film afterwards if you don't find it bass-deficient.


----------



## amphead

If you already have the 330uF purchased Regal, give them a try. If not, I would recommend about 470uF. Edit: with all due respect for Kvants listening impression with 32 ohm.......Grados? I can certainly recommend my photo flash caps Rubycon at 410uF for 64 ohm K701s. Generally speaking, I like Solens in the power supply better than I do as signal coupling caps.


----------



## regal

I have a pair of 470uF Nichicon PW(M)'s 250V

http://products.nichicon.co.jp/en/pdf/XJA043/e-pw.pdf


 would these be good output caps?


----------



## ericj

Quote:


  Originally Posted by *da_burl* /img/forum/go_quote.gif 
_Look out ericj, I just got back from the Thrift Store 
	

	
	
		
		

		
		
	


	


_

 

hahaha. 

 Well, you could gut it and fit several shelves in it. My shelves are supported by 1/4" all-thread from the hardware store. 

 Maybe you can chop off the ends and lay it on it's back?


----------



## ericj

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I have a pair of 470uF Nichicon PW(M)'s 250V

http://products.nichicon.co.jp/en/pdf/XJA043/e-pw.pdf


 would these be good output caps?_

 

Personally, I think they will work just fine. 

 my old millett had 100v 470uf PW's as the output caps, and when i 'upgraded' to silmic II's, i couldn't tell the difference.


----------



## da_burl

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_hahaha. 

 Well, you could gut it and fit several shelves in it. My shelves are supported by 1/4" all-thread from the hardware store. 

 Maybe you can chop off the ends and lay it on it's back?_

 


 I haven't messed with taking it apart yet, but that's what I was thinking, laying it on it's back and somehow making new ends for it. I imagine a good amount of space it taken by the fan and motor, once that's out, it might have some room. I can see that the rear grille come off exposing the filters. The foam filter would probably good for some headphone use too. I'm pretty sure it's reticulated foam.


----------



## da_burl

Oh by the way, I went on a tear and got the amp wired up to the point that I have music!! It's a little late for my old self, so I am going to put on some white noise and go to bed. But it sounds nice after only an hour or so. I'll think of some words, to say, let's see, effortless and authority. How's that. 
	

	
	
		
		

		
		
	


	



 I've got Amperex Bugle Boy ECC88's and JJ Tesla ECC99's in there right now, and the 470uF Panasonic HS_TB's bypassed with .47uf Sonicap Gen II's in the output positions as my first test. Everything should start coming together a bit more tomorrow after all this stuff burns in a bit.
 Also have the Russian version to try, with Ebay 6922's and 6N6pi's. Don't have any that I have to change the resistors for yet, just the heater jumper.


----------



## amphead

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I have a pair of 470uF Nichicon PW(M)'s 250V

http://products.nichicon.co.jp/en/pdf/XJA043/e-pw.pdf


 would these be good output caps?_

 

Put those in for now and order a pair of these, that Da_burl is using.

 470uF Panasonic HS_TB's
 Edit: you might have some trouble finding those. Mazuki probably has a source for some Panasonics.


----------



## ericj

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Put those in for now and order a pair of these, that Da_burl is using.

 470uF Panasonic HS_TB's
 Edit: you might have some trouble finding those. Mazuki probably has a source for some Panasonics._

 

if you meant to say ts-hb, digikey stocks them, sells qty1.


----------



## da_burl

Sorry about the dyslexia. I had actually typed TS_HB then went back and changed it because I didn't think it looked right. 
	

	
	
		
		

		
		
	


	




 This is the part # from Digikey. I used 450v in the power supply (3) and the 250v in the amp boards (2)

 P10152-ND CAP 470UF 400V ELECT TS-HB 
 P10124-ND CAP 470UF 250V ELECT TS-HB 

 I am still less that 24 hrs into burn-in but it is really starting to come together.

 I'm torn between rolling in the other tubes just for a listen or give these at least the minimum 50 hrs.

 I'm also a bit bothered by the NFB settings, but I guess I'll figure out what I am supposed to be listening for. Right now I'm being fooled by the apparent change in volume when changing the setting, and unable to detect any change in "focus" or "soundstage" very well.

 EDIT: Just figured it out by finding a post on about pg. 9 of the hdwz thread. Turns out I had it back a-wards as usual 
	

	
	
		
		

		
		
	


	




 I'm in a whole new world now with this thing!! Can I get a WOW??????

 Guess it's officially time to move everything down a line in my sig to put this at the top 
	

	
	
		
		

		
		
	


	




 My main cans now are lowZ AKG 701's, 2nd place are my 250 ohm pre-2005 DT880's, so I have a little bit of both worlds to experiment with.


----------



## regal

the Rubycon website is useless, does anyone have a part# for the largest uF 25mm Photoflash cap ?


----------



## da_burl

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_the Rubycon website is useless, does anyone have a part# for the largest uF 25mm Photoflash cap ?_

 

E BAY ??


----------



## amphead

Here is a link to some 430uF Rubycon photo flash caps. Remember you have to solder on some stiff leads to the terminals.

RUBYCON PHOTO FLASH / STROBE ELE CAPACITOR 430UF 350SV - eBay (item 180208139144 end time Apr-17-08 06:32:44 PDT)

 Well............first off, let me say that the amp is sounding wonderful. Now for some completely bizarre news about my amp. It is one robust build. I took it to my brother-in-laws who has worked as a professional audio engineer. Put it on his coffee table which is almost 2 feet tall. We had some dinner with my sister cooking the bratwurst, cabbage and potatoes. Nice dinner.........but from the dining room I heard a thud. The rotweiller playing around in the living room had bumped the coffee table and my amp was upside down on the floor resting with transformer and tubes holding up the chassis. After a short coronary, I picked up the amp carefully. It's about 26 lbs, and solidly built. Looked at the boards, and two tubes were just slightly cocked. I straightened them, about 4-5 degrees. Inspected for cracked boards......No. Looked for ripped out caps....No. Found no damage at all visually, and it had landed on carpet instead of bare floor. Plugged it in and listened. Sounded great........no damage.  Nothing like this, will ever happen again. No more chances.


----------



## tomb

Wow - glad to hear your Bijou is OK, Amphead. You've certainly put a lot of work into it. The pictures I've seen look great!

 When I was a lot younger, my dog wrapped his leash around my telescope tripod once. Unlike your experience, the result wasn't pretty.


----------



## amphead

Thanks TomB, yeah it was a very close call. One that won't be repeated by me.  The build still has some cosmetic features to be created on top of the amp, and for electrical isolation.


----------



## runeight

amphead, glad to hear there is no damage. Especially because of all the great work you've done on the chassis. Looking forward to the follow-up photos.


----------



## amphead

Tried putting a couple of Jensen .1uF 630v on the amps across the output caps. This did not produce a noticeable change to the sound, so I removed them. They were left over from another project. On to the design for the top of the amp. In general, tube amps need to shield the amplifier circuit against external noise or EFI and that needs to be incorporated into what goes on there. If I turn the NFB up past where I really need it, there is some high pitched buzz. I tried to eliminate it with the J1 mod, but there was no change. I am going to put a temporary cage over the boards to see if that is the source. Edit: the bulk of the filament wiring runs inside the chassis, but underneath the amp boards. This is another possible source for that. The amp really sounds good, but I want dead silence even with NFB turned up past where I need it.


----------



## da_burl

I rolled to the Russian edition today, Sovtek 6922's and unknown 6N6P-i's from ebay. 
 Was a little concerned, my B+ would not adjust up to 250v, even after an hour. It would only get about 246v before the pot started clicking. And everything seemed really "warm", but I didn't want to actually put my hands on anything 
	

	
	
		
		

		
			




 So I decided to be patient, and after 3 hrs. or so it now had stabilized enough that it is now adjusting correctly again. Guess there was a lot of crud to burn off of these tubes.
 I must say I really like the sound of this combo too. I need to get both sets burned in reasonably well, before I make a final decision, but they both sound great. I just got a set of HD580's, and the new tubes seems to make them a little more airy and detailed.

 That's not to mention that I could try different combinations between the input and output tubes as well. I don't think there will ever be a final decision, I think most combinations will sound great in this amp.


----------



## ericj

Quote:


  Originally Posted by *da_burl* /img/forum/go_quote.gif 
_I rolled to the Russian edition today, Sovtek 6922's and unknown 6N6P-i's from ebay._

 


 How bright are the heaters on the Sovtek 6922's? Or, do you have any pictures? 

 I've heard scandalous rumors about 6N1P's being sold as 6922's - which would be inappropriate as they are decidedly different tubes. 

 The 6N23P, however, is almost precisely a 6922. 

 Sovtek is mostly in the business of relabeling NOS tubes, imho, so, I'm curious what they're re-branding. My 6n1p-ev tubes are Sovtek branded but also bear the Voskhod rocket logo. I understand that all 6n1p tubes ever produced were produced at Voskhod, so the only differences are the -VI version vs. the ruggedized miltary -EV version. 

 The thing is, with the 600ma heaters, the 6n1p is Really Really Bright. 

 About your 6N6P-I tubes - what markings do you have? If there's a little pentagon, they were made at the Novosibirsk factory. If the 6n6p designation is inside a diamond, that may mean they were manufactured at the Reflector factory.


----------



## da_burl

Hey ericj:

HERE's a link to the 6n6p-i;s. My cyrillic is not too great, but they don't say 6n6p-i anywhere on them. To my eye they have 6H6 <square> <backwards N> and 8911 below that, and at the bottom OTK and a 1 ohm lookin thing inside a "quadragon" hah hah.

 I ordered eight, and five survived the trip (one more might be salvageable when I empty the shop vac) 
	

	
	
		
		

		
		
	


	




 They light up much brighter than than the 6922's. the 6922's were these. Pretty much no debate there, unless they were stripped and relabeled somehow (although they look like that's entirely possible) 
	

	
	
		
		

		
		
	


	




.

 The 6922's are definitely shorter and a little "squatter" than the 6n6p-i's, so I got that goin' for me 
	

	
	
		
		

		
		
	


	




 This is quite interesting, there really seems to be no end to the possible tubes you could roll into this amp. I foresee socketing the cathode resisistor in my future! I think I mentioned that this is my first venture into total tubeness, and I've got a lot of googling to do!

 EDIT: It's now been 12+ hrs. and these tubes are really sounding nice. 250V is stable IMO. They also have a little more "punch" in addition to my other subjective evaluations. Went back to the AKG 701's just to make sure. Things are really singin'


----------



## miky

Quote:


 My cyrillic is not too great, but they don't say 6n6p-i anywhere on them. 
 

It's 6N6P-I in cyrillic.


----------



## amphead

Bought an 8 footer 1/2 inch aircraft aluminum tubing. Also some 1/2 inch thick lexan. Lexan will allow for a view of the tubes from the front. The aluminum tubing will be cut in lengths that provide 3 rails on the left and 3 on the right, while fixed to the lexan front panel, which will be lit from below with leds. Probably hard to visualize but it will enclose the amp and power supply boards.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_...lit from below with leds. Probably hard to visualize but it will enclose the amp and power supply boards._

 

Not hard to imagine at all. LEDs. You've really got my attention! Are you getting power to them from the secondary PS you added? (or was that someone else? Could be. I need more coffee this morning.)


----------



## ericj

Quote:


  Originally Posted by *da_burl* /img/forum/go_quote.gif 
_Hey ericj:

HERE's a link to the 6n6p-i;s. My cyrillic is not too great, but they don't say 6n6p-i anywhere on them. To my eye they have 6H6 <square> <backwards N> and 8911 below that, and at the bottom OTK and a 1 ohm lookin thing inside a "quadragon" hah hah.

 I ordered eight, and five survived the trip (one more might be salvageable when I empty the shop vac) 
	

	
	
		
		

		
		
	


	



_

 

Odd that there are no other markings on the 6n6p-i. i wonder what the OTK mark means - lots of russian tubes have that. 

 Way bad luck that some of them didn't make it intact.


----------



## Ferrari

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_Odd that there are no other markings on the 6n6p-i. i wonder what the OTK mark means - lots of russian tubes have that. 

 Way bad luck that some of them didn't make it intact._

 

*OTK* stands for *O*tdiel *T*echnicheskovo *K*ontrolya, in English roughly Bureau of Technical Control, which indicates that military standards are applied. (With a little help from my colleague in Ukraine 
	

	
	
		
		

		
		
	


	




 )


----------



## ericj

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_*OTK* stands for *O*tdiel *T*echnicheskovo *K*ontrolya, in English roughly Bureau of Technical Control, which indicates that military standards are applied. (With a little help from my colleague in Ukraine 
	

	
	
		
		

		
		
	


	




 )_

 

So what does the number after it mean?


----------



## Ferrari

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_So what does the number after it mean?_

 

I really don't know. On my 6N6P-i there is an "1" inside a rectangle 
	

	
	
		
		

		
		
	


	




 after OTK.
 While on the K75 PIO caps I used in my amp, there are 4 numbers (9104) in front of OTK.
 These 4 numbers (9104) probably indicate that the caps are produced in week 4 of 1991.


----------



## amphead

Quote:


 Not hard to imagine at all. LEDs. You've really got my attention! Are you getting power to them from the secondary PS you added? (or was that someone else? Could be. I need more coffee this morning.) 
 

Power will again be coming from the extra 12v power supply. However, I found a toroid for $12.95 sitting in a surplus store that has 5v, 9v and 12v taps on the secondary. One was 12v at 1 amp. Toroids are normally quieter, and I am in the process of trying to remove that NFB side effect. Edit: my idea is to have 4 leds mounted to the bottom edge of the lexan front panel, which is on top of the amp and they will be wired to come on when power is applied.
 __________________


----------



## ericj

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Power will again be coming from the extra 12v power supply. However, I found a toroid for $12.95 sitting in a surplus store that has 5v, 9v and 12v taps on the secondary. One was 12v at 1 amp. Toroids are normally quieter, and I am in the process of trying to remove that NFB side effect. Edit: my idea is to have 4 leds mounted to the bottom edge of the lexan front panel, which is on top of the amp and they will be wired to come on when power is applied.
 ___________________

 


 How much power are these LEDs likely to draw? 

 Call me a cheap person, but, wouldn't it be possible to just hook up a voltage doubler and full wave bridge rectifier to the 6.3v heater supply? Or just the rectifier and a bit of a capacitor. 

 I mean, we're talking about maybe at the outside a few hundred mA of LEDs, right?

 Edit: Oh wait, you're implying that the LEDs come on when the amp is plugged in regardless of whether it's turned on?


----------



## bhjazz

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_How much power are these LEDs likely to draw? 

 Call me a cheap person, but, wouldn't it be possible to just hook up a voltage doubler and full wave bridge rectifier to the 6.3v heater supply? Or just the rectifier and a bit of a capacitor. 

 I mean, we're talking about maybe at the outside a few hundred mA of LEDs, right?

 Edit: Oh wait, you're implying that the LEDs come on when the amp is plugged in regardless of whether it's turned on?_

 

Oh, I thought the second transformer would be hanging off of the IEC just like the main transformer is...lol... I guess it could also mean that the lights come on when the switch comes on. So many options! 

 DIY rocks! 
	

	
	
		
		

		
		
	


	




 The LEDs, I think, would definitely take that much power. I know a few of the blue ones at superbrightleds are around 20ma, and deliciously bright.

 Anyway, can't wait to see it, amphead. Sounds like it's gonna be special!


----------



## ericj

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_The LEDs, I think, would definitely take that much power. I know a few of the blue ones at superbrightleds are around 20ma, and deliciously bright._

 

20ma is the *maximum current they handle. They could perform well with a lot less, and have a longer lifespan. 

 Of course, while we're talking about brightness, for the sake of clarity for lurkers - because all of us already understand this - it's important to pay attention to the fact that the minicandelas rating is a rating of how bright of a dot your lamp can put on the wall. LEDs generally have a reflector around the emitter. As the viewing angle afforded by the reflector shrinks, the MCD rating increases. 

 Thus, my 22,000mcd blue LEDs are indeed eye-stabbingly bright, even at half their rated current, but with their 6-degree viewing angle, seriously don't illuminate a large area.


----------



## amphead

The removal of my 300ma rated 12vdc radio shack box transformer, is due to poor construction. It runs warm with just the leds in the power switch. The toroid that I found is small about 3.5 inches across and admittedly extreme over kill for running my leds, however I don't mind over-rating for that application. Its donut shape will be easy to mount. As far as my leds go, the power button led is on anytime the iec is plugged in, and the 4 leds under my lucite(not lexan) front panel will come on when the power button is energized.


----------



## da_burl

I'm not going to have any LED's in mine, but I may be trying to squeeze in another xformer and PS for an Alien Dac and the optivol kit someday.
 I don't even have the LED for the original amp installed


----------



## bhjazz

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_for the sake of clarity_

 

Exemplary description. Bravo!

 /gloved golf claps

 And knowing this information certainly makes it easier to calculate other resistor values that can extend the life of them. As opposed to being stuck with one value...that gives you one lighting option.


----------



## ericj

Quote:


  Originally Posted by *da_burl* /img/forum/go_quote.gif 
_I'm not going to have any LED's in mine, but I may be trying to squeeze in another xformer and PS for an Alien Dac and the optivol kit someday.
 I don't even have the LED for the original amp installed 
	

	
	
		
		

		
		
	


	


_

 

I have the LEDs on the amp boards. I need to go back in and increase RLED again because i want their light to be less prominant. 

 I need to set up a tripod or something so i can do low-light digital photography without streaking and show you all how well my bijou glows in the dark with 6n1p-ev + 6n6p.


----------



## amphead

Low light photography should look awesome with your amp. 

 So the lucite panel was drilled for 4 instead of 3 rails on the right and left, and I'm cutting the aluminum tubing pieces to size. Edit: I went back to 3 rails L/R because 4 rails looked out of proportion.


----------



## Cloud

is it possible to use 2 seperate transformers? ie. 1 for the 260V and 1 for 6.3V?

 I have problems sourcing for the 370DX or its equivalent here in singapore. Import will be my last resort as the shipping kills.


----------



## runeight

hi cloud. this is no problem. just remember that the 260V is really 260-0-260 which is the same as 520VCT.


----------



## Ferrari

Cloud, if it's difficult to source a transformer with 260-0-260 secondary, you can go alternatively for 250-0-250 secondary.
 I noticed that transformers with 250-0-250 secondary are generally easier to source, at least in Europe.

 For my proto, I have used this (maybe a bit oversized) 250-0-250 secondary transformer with excellent results.
 The PS is set at 240V of course.


----------



## runeight

Gents, if you use a 250-0-250 transformer and if you have the available extra heater current, try using an EZ81/6CA4 rectifier. You can probably get 250VDC out of this combination. This tube is in current production

 In fact, with all of you guys using the 6N6P for the output tubes, I'm thinking that everyone could start using the EZ81. It will drop less voltage at the higher currents drawn by the 6N6. I haven't tried this myself, but I believe it should work. The only thing that will happen is that the pass mosfet will get a bit hotter.


----------



## Cloud

hmm ok. Thanks for the advice both runeight and Ferrari


----------



## Ferrari

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Gents, if you use a 250-0-250 transformer and if you have the available extra heater current, try using an EZ81/6CA4 rectifier. You can probably get 250VDC out of this combination. This tube is in current production

 In fact, with all of you guys using the 6N6P for the output tubes, I'm thinking that everyone could start using the EZ81. It will drop less voltage at the higher currents drawn by the 6N6. I haven't tried this myself, but I believe it should work. The only thing that will happen is that the pass mosfet will get a bit hotter._

 

Good tip , runeight !
 My 6.3V secondary is rated @6A, so I will try the EZ81/6CA4 rectifier in my next PS.


----------



## amphead

Finished installing the guard railing/lucite panel on the top of the amp. It has 3/16 inch thick aluminum plate anchoring the rails in the back. I will install the toroid 12vac tomorrow, in place of that Radio Shack xformer. I have a theory that I get some high pitched buzz from a noisy alpha pot in my NFB circuit. To test this theory, I will install a quality metal film resistor across the pot connections on both amp boards, after disconnecting the pot. Probably a 100k, and then a 200k metal film. If I still get the buzzing, at least the pot is vindicated. Edit: first I am going to solder a wire onto the body of the NFB pot and run that to star ground.


----------



## amphead

Soldered a wire onto the body of the NFB pot and then to star ground. No change to the buzz sound. I will try the resistors tonight and see what that does. The sound with tubes and caps burned-in is just so incredibly detailed and with some very good soundstage. Nice bass too.


----------



## runeight

amphead, as a test, try moving the ps board farther away from the amp boards.


----------



## amphead

OK, that's next. I'll solder some extension wires from power supply to amp boards and have the PS sit off of the chassis. If that's it then I will just get another metal substrate and drill for a new topology. thanks


----------



## amphead

The power supply board was moved away from the amp boards and there was no change. My next hunch is that its mains noise coupling into the preamp somewhere. It isn't 60 cycle however, but more like a fizzy static sound. Second choice would be heater circuit getting into the input path off-board. This is when NFB is increased therefore the preamp becoming more sensitive.


----------



## amphead

Tried removing the power-on button from the circuit for less ac wiring, with power coming directly from the iec. Still no change, so my next test is to wire ac heaters directly to the transformer and bypassing my terminal block, which shares a ground and hv connections. The caps and tubes are producing sound similar to the Orpheus system that I listened to, nice and smooth with incredible detail. Gotta get rid of the fizziness with moderate NFB. I may have to remove everything from the chassis and lay it out on a piece of plywood to troubleshoot.


----------



## bhjazz

Lions and Tigers and Bear, Oh My!

 Same problem...obviously different characters! 

 Hey amphead, I don't know if you've been out to Bottlehead.com, but your problems sound vaguely familiar to some things that happen out there. Especially if it doesn't sound like 60Hz. If you want to take a step back and try to find any "I hadn't thought of that" issues, take a browse through their forum. I remember modding a kit from Doc B and was able to get the last bit of itchy fizz out of it due to similar issues others had seen.


----------



## willisv

I thought i would update some of the changes i have made to my Bijou recently.

 After some discussion with Mazuki I decided to try using the Amperex 8416 tubes in the input. The advantage was that these tubes are basically the same construction as the very expensive 6DJ8 variant at a fraction of the cost. The only problem was that they need 12 volts of heater current, so some changes needed to be made. Luckily I am using the R80-36 R-core transformer so getting the proper heater voltage was possible without buying another transformer. Thanks to Runeight and Mazuki for helping me troubleshoot the wiring to make this happen.

 These tubes sound absolutely amazing, better than anything I have tried to date including the Jan Philips 6922, the Sovtek 6922, or the Philips 6DJ8. I am very happy with these tubes and have no plans to upgrade as I'm not sure what would sound better.

 Yesterday I installed two 400V 10uF Mundorf M-caps as bypass caps for the output, and this also made a noticeable difference. I am sure that they need to break in a little, but they sound very very nice. The highs are much more detailed and smooth since putting these in and I don't have to use as much negative feedback to make it sound good. Also, one of the things I have noticed is that I have to warm up the Bijou for an hour or so before it starts sounding it's best.

 Amphead, have you checked the ground connections on your Alps pot? I had the ground wire from my rca's come off my pot and it made my amp hum really bad.


----------



## amphead

Looking at some of what others have done to reduce noise, may or may not be prudent with the Bijou. Such as High voltage snubbers and filament snubbers. Short of that, I am in the process of rerouting some filament wiring.


----------



## amphead

Rerouting filament wiring has helped a little, and with NFB at 1/4 turn there isn't any appreciable noise, with very good sound overall. More NFB, would give me more presence and slam, but dynamics are definitely there as it is. Next step is to put input wiring into some grounded shield cable, running the shield to star ground. And the same for heater wiring. This should remove some more of the noise. Certainly is a world class headphone amp. Dare I say it............Hell yes!


----------



## dcheming

Can anybody comment on how well the Bijou performs as a preamp? I searched a little but couldn't find any info on this. A Bijou will soon be replacing my Xiang Sheng 708B which I'm currently also using as a preamp in my computer setup so any comments on this would be appreciated.


----------



## regal

Quote:


  Originally Posted by *dcheming* /img/forum/go_quote.gif 
_Can anybody comment on how well the Bijou performs as a preamp? I searched a little but couldn't find any info on this. A Bijou will soon be replacing my Xiang Sheng 708B which I'm currently also using as a preamp in my computer setup so any comments on this would be appreciated._

 

too much gain


----------



## runeight

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_too much gain_

 

dscheming, wIth no NFB the Bijou has a gain of about 25 into a high impedance load like an amplifier. This is probably too much for a preamp. You can try it, but the volume positions may be very difficult to manage.

 You can apply more NFB to reduce the gain, but the NFB in the Bijou is there only to handle difficult low impedance headphone loads. When driving high Z it's generally better to not apply too much NFB. Still, you can try it to see if you're ok with the sound of it.


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Rerouting filament wiring has helped a little, and with NFB at 1/4 turn there isn't any appreciable noise, with very good sound overall. More NFB, would give me more presence and slam, but dynamics are definitely there as it is. Next step is to put input wiring into some grounded shield cable, running the shield to star ground. And the same for heater wiring. This should remove some more of the noise. Certainly is a world class headphone amp. Dare I say it............Hell yes! _

 

amphead, since you're doing all this rewiring, it would be good to shield the signal wires in and out of the NFB pot too.

 World class is nice to hear.


----------



## GeWa

My power supply board is finished but I still need to order a few parts for my amplifier boards, hence this question; Any recommendations for C1 and C5 on the amp boards?

 Regards


----------



## amphead

Gewa, try these.
 The photo flash caps require that you solder on some stiff leads.

 C1 - 140-XRL250V10-RC 10u/250V MouserXicon Al cap 10 x 20
 C5 - RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 360025524313 end time Apr-19-08 15:31:29 PDT)

 Installed shielded wiring on the input of the amp for some more improvement once again. Next, I will install shielded wiring on the NFB circuit, as suggested by Runeight.


----------



## amphead

Installed shielded wiring for the NFB circuit, with an additional reduction in noise. Odd thing is, that the Alpha pot measured continuity with my meter across L/R channels on all three lugs. Aren't the channels separate from left to right on the dual ganged pot? Runeight?


----------



## runeight

The side of the pot that is connected to the output is also connected to ground through a 10k resistor. Since both pots are grounded there is continuity between them. The continuity should be fairly high resistance, never less than 20k. If it's low resistance then there might be a problem.

 Or do you mean that the pot had continuity when it was out of the circuit? If so, that would be a problem.


----------



## amphead

Yep, my bad, I was measuring it in the circuit. Late nights.  It's about 18K, although I am getting an unusual effect. With the pot turned down, I get sound in one channel, which gradually goes to both channels as the pot is increased to maximum. With it turned to maximum, detail and soundstage are incredible. This I am attributing to a more linear response with max NFB, and 64 ohm K701's. The only downside is that anything past 1/4 turn has a small amount of noise, and unbalanced volume below 2/3 turn of the pot. I was saying earlier that the noise wasn't 60 cycle, but it's probably the 120hz harmonic, so same difference. Before figuring out the balancing issue, I am going to install the shielded wire on the volume pot. Thanks for the quick follow-up Runeight!


----------



## amphead

Balance between L/R channels returned to normal after swapping the output connections. With shielded wiring on the volume pot, there was not any reduction to noise. The only wiring left would be to shield the heaters, but that would not be too easy. Running DC heaters instead of AC, might reduce the quality of the sound, while reducing noise. And how would they be grounded? Runeight? Edit: actually I don't want to use DC heaters, so maybe some quieter 6DJ8, or trying to shorten the path of the heater wiring and twisting it tighter. Proper lead dressing is what would normally correct AC filament wiring noise. Also, when I turn the NFB pot clockwise, volume increases, and this would indicate that it's actually reducing NFB, since increasing NFB reduces gain. Edit: what would be the effect of wiring all filaments in phase for each stage, and adding a 100 ohm hum pot across the filaments, like this diagram:


----------



## runeight

amphead, i'm afraid you can't use a humpot. The heater circuit is already biased to about 40V by a voltage divider on the PS. This is there to reduce the HK voltage on the phase splitter and upper output triodes.

 I don't think you are having heater hum problems and so I don't think DC heaters will matter.

 I think this is a grounding issue somehow. There is one common feature between your amp and mine - a single top plate without metal sides. I had a similar buzz problem with my prototype build. I could not elminate it except (as explained on the website) by creating a short antenna wire from the rectifier that canceled the buzz field. In my case I think the problem was because the rectifier was too close to the amp tubes. But it could be that this is caused by the flat plate as the ground plane. I don't understand why this would be at the moment, but it is the only hunch that I have.

 The other builders who have used a Hammond chassis with the boards mounted on the top are not reporting this issue.

 You are correct about the NFB. When the volume gets louder this is less NFB and not more.


----------



## amphead

If the hammond chassis, is steel and not aluminum, then the iron in the hammond chassis creates voodoo, by magnetically coupling radiant fields to ground. Where my stainless steel is obviously non-magnetic. However, this hunch would not wash, if others are having success with aluminum enclosures.  I'll take a look at your antenna on the website. At least I can try to figure out what the Hammond chassis is doing. This amplifier is well worth the challenge of getting that black background. I truly am in love with the sound. Thanks for you reply.


----------



## amphead

Here is another part of the equation: I like the sound best with my lo Z phones(64 ohm), with minimal NFB. Minimal NFB, means that the noise canceling created by NFB for lo impedance is not in play. So I just realized it, what I am fighting is the reason we are using NFB, which is to use lo impedance phones.  So in reality, I am trying to get around using very much NFB and this is while using my lo Z phones. Is this an uphill battle? Of course it is. My sound is very linear with minimal NFB. But trying to get the circuit to run quietly with lo Z and minimal NFB at the same time..........is not the way it was designed. But it is worth the challenge. Sorry I put you guys through my learning curve.  It does sound very good with lots of NFB(quiet), but it sounds Orpheus good with minimal NFB(linear).


----------



## runeight

Although it might considered normal to have minimum NFB for high Z phones and more NFB for low Z phones, where to set the NFB pot seems to be very personal to each person's ears. So, while the amp is designed to be able to provide an adequate range of NFB for typical range of headphones, it should allow you to operate with low Z phones and no NFB if that is the best sound for you.

 Hopefully we can solve this buzz problem.


----------



## amphead

The volume balance problem has returned to the amp, with the NFB pot gradually increasing left phone volume, with right phone staying the same, over the full travel of the pot. Earlier, I swapped "inputs" (not outputs as I had said) L/R and the problem went away. I am going to pull an RK27 off of another amp project temporarily to vindicate or not the Alpha pot. Tried to create an antenna for noise reduction, by inserting a well insulated wire(1 foot) into the connector for pin1 of the rectifier, and taping it to the metal top panel. This was either the wrong way to do it, or it didn't work. So next step try RK27. The only problem would be it's 50K not 250K. But this is just a test.


----------



## amphead

Swapping the NFB connections on a single amp board, not both got rid of the balance issue. That is strange because on the other end at the pot both channels are wired the same. Installed the RK27 pot in place of the Alpha pot. Hey, is it fixed, almost no noise for any position of the pot. Well not likely because it's a 50K pot, so the full 250K that was giving me the best sound is not available. Time to locate a quality pot with more range. 200K would be enough to get the sound I need. However 250K is alot easier to find.


----------



## regal

if 250k was giving the best sound you may just want to go sans NFB. This is best anyway.


----------



## amphead

That may be something to try next. I'll go look at Alex's website for the component changes. Without NFB, I have to find a way to get rid of the buzzing, but I don't know who has built the amp, while using K701's and also is not using NFB.


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_The volume balance problem has returned to the amp, with the NFB pot gradually increasing left phone volume, with right phone staying the same, over the full travel of the pot. Earlier, I swapped "inputs" (not outputs as I had said) L/R and the problem went away. I am going to pull an RK27 off of another amp project temporarily to vindicate or not the Alpha pot. Tried to create an antenna for noise reduction, by inserting a well insulated wire(1 foot) into the connector for pin1 of the rectifier, and taping it to the metal top panel. This was either the wrong way to do it, or it didn't work. So next step try RK27. The only problem would be it's 50K not 250K. But this is just a test._

 

amphead, the best way to try the antenna is to attach a clip lead to the pin of the rectifier. Insulate the other end of the clip lead so that you don't accidentally touch it. Then position the wire in different locations above the circuitry. You will almost certainly hear increase in noise with almost all of the positions of the wire. But with any luck you'll find a position that reduces the baseline noise. This is what I did.

 Then I took a piece solid wire, soldered it to the rectifier socket and bent it into shape to stay where the clip lead had the best result. My Bijou has this feature right now and it is very quiet. This is not elegant, but it is a solution if it works.

 Also, regal's suggestion is a good one. You may not want NFB for any set of headphones. In which case see the website for what to do to remove the NFB entirely from the circuit. Edit: I see that you're already checking this out.


----------



## amphead

The NFB has been removed, but I didn't have any quality resistors handy in the 300 ohm range. So, not wanting to wait I pulled a pair of 825 ohm Riken resistors and put those on in the R1 positions. Knowing that the large value there, wouldn't be subtle. The sound without NFB is definitely in line with what I was getting with minimal NFB, as long as I imagined the 300 ohm sound that will replace those Rikens. With large resistance in R1, the buzzing is more of a nuisance. I tried a clip lead on pin 1 of the rectifier tube and moved the wire to different positions over the boards. There was a very slight reduction near the front of the 6DJ8's, but the noise wasn't reduced enough on my amp. Tube shields? I wouldn't like the look too much, but it seems like my preamp tubes might be coupling the hum. It's quite a challenge, but I'll keep banging away.  Edit: with lo Z phones, 825 ohms at R1 and the volume at maximum, you can draw blood from your eardrums as you watch the headphone drivers explode.(don't try it).


----------



## amphead

Well, I never increased the volume past 1/4 turn with those Rikens. Wondering if many who get lower noise, are using JJ ecc99, instead of the ecc88 Nationals that I'm using. There is of course the difference in heater wiring between the two tubes. Thoughts?


----------



## runeight

The amp has a gain of about 25 with no NFB. This is pretty high and will limit the volume range for low Z headphones. Another reason for NFB.

 I don't think that the buzz is heater induced. Heater noise would be a hum at 60Hz and fairly easy to detect. The noise that you are getting is from the PS and it's most likely a grounding issue somehow. Not that you don't have the star ground wired correctly, but that there is some HV noise leaking into the ground circuit.

 I hate to ask you to just keep trying things, but another idea would be to provide a much larger ground. Perhaps by connecting the top plate to another big, good conducting chunk of metal. Also, if you have a metal chassis with sides you could place this upsid down under the amp instead of the wooden base, making sure that it is grounded too.

 Since you've already moved the PS far away from the amp boards and the problem stayed the same, then we can be pretty sure that it's not EM radiation from the PS. You could try this test again just to be sure, but if moving the PS closer and farther away has no audible effect on the buzz, then it's not PS radiation. Hence, my thought that it is a grounding issue of some kind.

 The other possibility is that the B+ is really noisy. This would mean that the regulator is not working quite right and is passing the 120Hz ripple to the regulated side. This regulator has a very high ripple rejection, so it is hard for this to happen, but it could be happening nonetheless. Do you have a scope where you can look at how clean the B+ is?

 You might also check the ground connection from the PS to the star to make sure that it is really solid.


----------



## amphead

Quote:


 if you have a metal chassis with sides you could place this upsid down under the amp

 The other possibility is that the B+ is really noisy.

 You might also check the ground connection from the PS to the star to make sure that it is really solid. 
 

The mosfets give me a little concern, now that you mention it. I'll try the other two ideas for now. I removed the Rikens and installed some garden variety 330 ohm carbon films on R1. Pleasing sound, with just the buzz to contend with. Then I tried a goofy tube shield experiment. Carefully wrapped the preamp tubes with heavy duty foil and provided a ground wire to star ground. No change whatsoever. So now I'm moving on to your suggestions. As far as trying your suggestions, I don't mind at all. Yes, I have access to a scope at an engineers bench, but not here.


----------



## amphead

Checked the ground wire for the PS, and it seems solid. While thinking about grounding issues and researching the net, I read that the negative lead of the first filter cap should be run straight to star ground to avoid rectifier current spikes. I added a wire there and connected it to star ground, with absolutely no change to the sound.


----------



## runeight

Yes, that is one preferred technique for grounding the PS since the rectifier delivers fairly large spikes to the first cap. But, I'm not surprised that it didn't make any difference here. There is something else going on.

 I must admit to being a bit at a loss for the moment. Is your star ground also connected to the line ground?

 I guess the next step is to view the B+ on a scope. Maybe it has some spiking on it.

 Have you tried moving the PS away from the amps again. Really far away from everying including the wiring?


----------



## amphead

You are making me think that the regulators, are the source, and are not rejecting enough of the 120HZ ripple. Short of ordering more of those, I need to get the amp over to the engineering bench. The ripple will definitely be upstream from those regulators, but if I see it riding on the B+, then the mosfets are possibly deficient. Then what? Replace them or try different ones. My 370DAX pumps out 284-0-284 unloaded and 274-0-274 loaded. Are they having trouble taming the beast?


----------



## Ferrari

The best thing is using a scope to check the signals behavior of your build. There must be some silly thing which causes problem, this amp is not that complex. Also, some close-up pics of your build may help at this stage.

 The voltage numbers of the tranformer seems to be normal, even 10V more or less shouldn't be a problem. We have seen that in the prototyping phase.


----------



## amphead

Yeah, thanks Ferrari! I am considering the effect of doubling the size of C1 as a test (2x680uF). I hope the current surge from increasing capacitance there doesn't overtax my mosfets. This would just be something to try tonight, before I have a chance to put it on the scope. If the noise is reduced at all, then the regulators might be the cause.


----------



## amphead

Hmmm.......There was an increase to the noise, and a change to the amps signature. Seemed pleasing enough, but with a kind of airy detailed effect. Who knows what its doing really. Vocals seemed different, but maybe I was imagining that. So onto the scope for some answers about the fizzy buzz.


----------



## amphead

Quote:


 If the output of the regulator has 120 Hz ripple. What is a possible cause?....................
 This is typically caused by a power supply electrolytic filter capacitor losing capacity due to age or some other cause. The ripple voltage on the input to the regulator increases to the point where the “bottom of the ripple” is below the regulator drop out voltage , so the regulator output drops on the ripple minimum voltage points. The ripple is 120Hz because of the use of a full wave rectifier with a 60Hz line. 
 

I found this info while researching, and its a given that the filter capacitors must do their job. At least its something else to try. Maybe C6, C4 or C5?


----------



## amphead

Well my engineer brother-in-law doesn't get back until friday. He's in Germany attending an elevator controls convention. So no scope until tomorrow night. The test that I should have done last night, is what I will do tonight. Double the capacitance of C4(2x680uF) instead of C1. Also, I haven't been happy with my ground sink being the stainless top plate. As an experiment I am going to get a piece of copper pipe from the hardware store. This will be installed underneath, inside the chassis and the star ground will be soldered to it. My stainless plate doesn't accept soldering, and copper pipe will. Soldered junctions are more reliable than mechanical screws and nuts, for shunting to ground.


----------



## runeight

amphead, it is very unlikely that the caps in the main filter section are failing so badly that the ripple into the regulator is causing it to drop out. It's possible, but I suspect that this is not happening.

 However, it wouldn't hurt to measure the voltage at C4 just to be sure. If it's well over 260V then ripple here is probably not a problem.

 The regulator has a very high ripple rejection. As long as it is not dropping out and as long as it is working properly, ripple on the B+ should be nearly unmeasurable.


----------



## amphead

Problem solved! So what was happening? Because I already had 1000uF 25v Silmic II on hand, I didn't purchase the Panasonic cap for C3. The Panasonic cap is 10x16 and the Silmic is 16x36. It wasn't easy to install the Silmic and it had to sit off the board about 3mm. That wasn't a problem but the 16mm diameter was. It practically touched the heatsinks for the regulators. It picked up noise inductively from the regulators. So as a test, I ran some wire and put it off-board. I also installed a 10 inch by 7/8 inch copper pipe inside the chassis and soldered the star ground to it, after pulling it from its mounting point on the stainless top plate. Noise dropped out completely. Sheer heavenly tones with no NFB and K701's. Thanks for the design and the help Runeight! Now I can concentrate on esthetics. Instead of an NFB control, I am thinking of going 50K RK27 left and right channels for volume with separate pots for volume. A volume balance control set-up.


----------



## willisv

Nice job on the trouble shooting Amphead!


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## runeight

This is great to hear.

 Also, with your problem fixed you might find that the variable NFB is actually useful. It might be worth a try if you want to take the time.

 Please tell us how your listening tests go.


----------



## amphead

Thanks, Runeight and Willisv! So the cap is still off-board until I get a suitable replacement. The copper pipe buss bar has been mounted in a sturdier fashion using white pvc on the sides of the amp walls. Listened to some Deardorf Jazz at 160kbps wma. Bass, sax and piano are right on the mark. Lively, crisp and detailed, while being smooth and satisfying. Almost sounds like a beer review. Then I listened to "No Quarter", Led Zeppelin at 256kbps Mp3. Robert Plants voice is just right there with me, extremely detailed and John Paul Jones bass is deep with some distortion unit cranking out those other-worldly bass sounds. The riff that Jimmy Page strums, has a nice midrange droning effect that puts you in a relaxing trance. Now, I have to be honest about where I am at in my build. If I turn the 50k RK27 pot from say 25 percent to 90 percent, there is a very slight buzz. Anywhere from 90 percent to 100 percent volume becomes dead quiet. I do, have to turn my source(Sony Walkman) way down of course. But then the sound is great and there is absolutely dead silence between notes. So that is where I'm at right now. And I'm happy to be there.  Those in-between points on the pot are definitely a curiosity. It's an easy thing to remove, because it's so small.


----------



## regal

Does anyone have a supplier and part# for the 600V B+ wiring? Ideally not wanting to buy a 100ft spool. Radioshack only sells 300V wire.


----------



## amphead

Regal, Navships is a good supplier..................

50 ft 20 AWG Silver Teflon Wire Black - eBay (item 300216516960 end time Apr-22-08 05:15:28 PDT)


----------



## runeight

amphead is your stainless plate floating or grounded?

 also, you might try using a static NFB setup. Put R1 back to 10k, put R12 back into the circuit and use about 200k in place of the NFB pot.


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## amphead

There is less noise with the top plate floating.Edit: depending on how I have the pot grounded it can be noisier. I have to finish deciding on how to keep the ground there.

 Would this volume mod work with low impedance phones and 50K RK27? 
 "R" would be 47K ohms.
 At first glance, the increase in source impedance might be beneficial in my case, where I have to keep the Walkman volume turned down.


----------



## fordgtlover

I am currently building my Bijou. However, I have some very strange measurements on one of the resistor values supplied in Jeff's kit.

 The required R9 & R11 resistor values are 475K, but I am measuring between 239K and 271K on all 4 of mine.

 They are Vishay RN55 resistors and have 4753F printed on them. 

 I have tested them with both of my multimeters, which are admitedly only relative cheap ones, but seem to measure the other resistors fine.

 Has anyone else had a similar experience with these resistors? Perhaps someone else with a kit from Jeff.

 What's the likelihood that the resistors are incorrect versus something wrong with my multimeters?


----------



## amphead

I would certainly believe 2 DMM's measuring the same value. Those points on the output tubes are pretty critical for you to use the right value. I would send Jeff a pm or an e-mail, and he will send you out replacements. You could use garden variety 1/4 watt metal film(not metal oxide) there temporarily. They are easy enough to pull and replace later. They sound approximately the same, but the VDs are better.


----------



## fordgtlover

Thanks amphead. I'll go buy some tomorrow.


----------



## GeWa

*amphead*

 I followed your advice (see post 314) and ordered me some of those Photo Flash cap's 
	

	
	
		
		

		
		
	


	




 Regards


----------



## amphead

They are very good in the Bijou. Cheers! 

 Runeight, when the pots wiper reaches full travel, noise is shunted to ground. I just realized it. So I need a mod that allows that to happen for all values of the pot.


----------



## fordgtlover

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_I am currently building my Bijou. However, I have some very strange measurements on one of the resistor values supplied in Jeff's kit.

 The required R9 & R11 resistor values are 475K, but I am measuring between 239K and 271K on all 4 of mine.

 They are Vishay RN55 resistors and have 4753F printed on them. 

 I have tested them with both of my multimeters, which are admitedly only relative cheap ones, but seem to measure the other resistors fine.

 Has anyone else had a similar experience with these resistors? Perhaps someone else with a kit from Jeff.

 What's the likelihood that the resistors are incorrect versus something wrong with my multimeters?_

 

Issue resolved - my stupid measurement mistake.


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_They are very good in the Bijou. Cheers! 

 Runeight, when the pots wiper reaches full travel, noise is shunted to ground. I just realized it. So I need a mod that allows that to happen for all values of the pot._

 

amphead, please pardon me for asking, but I'm not quite sure what you're trying to do. Is this the volume pot or the NFB pot?


----------



## amphead

Yes, the volume pot. Don't know if that mod shown below would be suitable for the Bijou. Where the pot is 50K and "R" is 47K. The increased input impedance would seem to work in my favor with lo impedance phones.


----------



## runeight

Oh. Yes, you can do this. But I don't think it will help much to reduce whatever noise remains in the system.

 Is it correct that most of the noise is gone, but there is still some for some positions of the vol pot? Whether there is NFB or not?

 Have you tried grounding the pot cases?


----------



## amphead

Well, I haven't tried putting static NFB back on the circuit yet. But as it is now, the amp sounds very detailed and quiet for 90 to 100 percent of the pot travel. There is a wire soldered to one of the screws on the pot and connected to star ground. I'll try this mod, because when the walkman is switched off, but still connected with the amp on there is a hum, which sounds like "loading" of the input. This is with the volume pot maxed out. With increased input impedance the loading might be reduced, which I think is a good thing. Not sure how abusive it is for the amps circuitry to have max volume, connected to a lo impedance load(phones) without NFB. My gut feeling is that the regulators work harder in that scenario.


----------



## runeight

Ok. I'm starting to get the picture.

 With no NFB the amp has gain about 25. With a typical source and max volume it seems like you should be getting very loud audio from the headphones. In fact, with low Z headphones, you shouldn't have to turn the volume up very much at all. This must mean that you have headphones that require a lot of power to drive. Is this correct? I'm sure that you've said what you're listening with, I just forgot.

 But, in any case, with typical headphones and typical sources, you shouldn't have to operate at max volume.

 The hum from the Walkman is a radiation problem when it is switched off. The portable CD player's output essentially floats when it's off and picks up hum from the EM in the room. 

 What happens if you dead short the input? Do you still get buzz at max volume?

 Now that the stainless top plate is no longer grounded, there is nothing shielding the components under the plate. And you mentioned that grounding the steel plate makes the buzz worse, which probably means that the plate is also picking up noise and introducing it into the ground. A guess at the moment, but possible.

 A question on the shielded wire. Are you running the ground connection through the shield? What I mean is, when you connect the input jack to the pot, is the shield connected to the jack ground and the pot ground? And then is the shield from pot to input connector on the board also wired the same way? If so, you could try another method.

 That would be to run a separate ground wire from jack to pot and pot to board. Then disconnect the shields from both ends and just connect one end of the shield to the star. This will eliminate ground current flow along the shield possibly coupling to the signal wire. The actual ground wire, being outside of the shield should not affect the signal.

 We're straining at gnats a bit here to try to squeeze out the last bit of noise. My guess is that if your top plate were a nice piece of copper, your amp might be very quiet.


----------



## amphead

Yeah, the copper top plate would look good, and would only add a little more weight. The stainless isn't all that lightweight. The Walkman is the 4GB mp3 player, which plays wma and wav files. Just happen to have 2 Rikens, 47K, 2 Watt left over from another project. Most of the noise is gone but when the volume pot is turned all the way up, it shunts all noise to ground. The phones would be plenty loud at 1/4 turn if the Walkman is turned to about half volume. The only reason for turning the bijou volume pot to full is to shunt all of the noise to ground.


----------



## amphead

The volume pot mod is actually pictured backwards, so that the volume increases counterclockwise. However, while it did increase input impedance a little, it created a noisy circuit as volume increases. I am going to return the volume pot to the original configuration. Edit: now the circuit is mostly quiet from zero to 50% turn of the volume pot, and dead quiet from 95% to 100%. This is wired exactly like the wiring diagram on the website. I'm not sure how I could rewire ground to make it dead quiet for all pot positions yet. At least I'm getting great sound and low noise for now.


----------



## amphead

Quote:


 That would be to run a separate ground wire from jack to pot and pot to board. Then disconnect the shields from both ends and just connect one end of the shield to the star. This will eliminate ground current flow along the shield possibly coupling to the signal wire. The actual ground wire, being outside of the shield should not affect the signal. 
 

Tomorrow I'm going to try this, now that I know what its trying to do. thanks


----------



## amphead

Fordgtlover, GeWa and anyone else who is just starting to build their Bijou.............not that I am at any less risk of being shocked by my circuit.............but I just want to say always give the circuit at least 15 minutes after being energized/de-energized before doing more work. Check the B+ with your meter and there will still be about 40 volts on the output tubes/output caps. This is very snappy even at such a low voltage and can bite. Discharge the output caps with a well insulated 1k resistor. Check with your meter before laying hands on the circuit to be sure. Don't be tempted to touch anything in the circuit with the iec plugged into the wall(Edit:use a non-conductive tweaker to adjust B+ pot). You can almost always avoid a shock by doing these steps. Also no pets or children should have access to an energized circuit. We just don't talk safety enough, so be safe.


----------



## fordgtlover

^

 Thanks for the timely reminder amphead. 

 I expect to power mine up for the first time over the next few days. I've read all of the warnings, and I will treat this baby with the respect it deserves.

 I'll make myself a nicely insulated 1K resistor, and I'm going out tomorrow to (re)buy some clip connectors for my MM. (Incidentally, lack of the MM clip connectors caused my problems in reading the 475K resistor yesterday - I misplaced my old ones 
	

	
	
		
		

		
			





 ).

 It will be a few weeks before I get the case, but I'll make certain that it is all bolted down securely on a temporary board before I turn on the power for the first time.


----------



## fordgtlover

I posted this question over at headwize, but the thread has moved on.

 This is the first time that I have used this type of transformer, and I am unsure of the usual (accepted and safe) way to deal with the unused and jumpered wires.

 I had planned to snip off the unused secondary wires and heat shrink the ends. As I'm using 240V I need to join the brown and black on the primary side. I'd planned to shorten these two, solder them and heatshrink them. And then finally leave all the wires that aren't connected to the PS board floating in the amp end bells.

 Is this OK?


----------



## amphead

This is from hammonds website for 240vac primary. 






 Until you are completely finished with your amp, you might keep the leads a bit long. Just use shrink tubing on the ends of the unused wires and coil them up and secure with a tie-wrap. This is to allow you to change your mind later and still have enough to work with. You can cut them short right away and put the shrink tubing on the ends, if you are confident enough as to how the build will progress.


----------



## fordgtlover

Thanks amphead. That's good advide about leaving the leads long to start with. Are there any downsides to leaving the insulated unused wires in the end bells?


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_The volume pot mod is actually pictured backwards, so that the volume increases counterclockwise. However, while it did increase input impedance a little, it created a noisy circuit as volume increases. I am going to return the volume pot to the original configuration. Edit: now the circuit is mostly quiet from zero to 50% turn of the volume pot, and dead quiet from 95% to 100%. This is wired exactly like the wiring diagram on the website. I'm not sure how I could rewire ground to make it dead quiet for all pot positions yet. At least I'm getting great sound and low noise for now. _

 

This description says that there is still a grounding issue. Most of the time you would expect that when the vol pot wiper is near ground (low volume) the amp would be quiet. And when it's far from ground (high volume) the amp gets noisy. But in your case is appears that the wiper is picking up ground noise.

 What happens if you just strap the input of the board to the input ground right on the terminal block. Does the amp get quieter or noiser?


----------



## amphead

Do you mean a small loop of wire on the phoenix connector that is attached from the signal in on the amp board to the star ground of the phoenix connector?


----------



## runeight

yes, a short piece of wire from the input terminal to the input ground terminal right at the board terminal block. I'd like to know what happens to the noise when you do this.


----------



## amphead

Ok, I'll give it a try. Also I will try that other grounding config. later.


----------



## amphead

So with the short wire running from signal input to star ground on the phoenix connector, there is a small steady buzz for all positions of the pot and with the same amount. There is of course a 100 fold decrease to volume of the music, where I can just barely hear it with the volume on the amp at max and the volume on the walkman at max.


----------



## runeight

OK. Normally, when you strap the input to ground with a very short wire, if there is noise coming from the input section (jacks, wiring, pot) then the noise will stop.

 In your case the noise is still there. This means that the noise is coming from somewhere else in the amp. There are three possibilities:

 1. Ground noise (could still be a problem)
 2. B+ noise (improbable but possible)
 3. Radiation into the tubes and components. Seems unlikely, especially if the steel plate is grounded

 We'll have to try to figure out which of these is the culprit.

 So, if you completely enclose the amp in a conducting, grounded box with the input shorted at the terminal block does the noise stop? If so it's radiation.

 If you put a scope on the B+ do you see spiking at 120Hz? If so, noise on the B+.

 If both of these experiments are negative, then it's still a grounding issue. At least that's my very best guess right now.


----------



## amphead

Grounding must be the problem. I tried another experiment, which was a different way of grounding the top plate, than connecting it straight to star ground. From the star ground connection on the phoenix connector, I put a 220K resistor on both amplifier boards and attached the other end to the top plate(I chose that value at random). This created some noise reduction and so maybe the boards hovering over the top plate(stray capacitance or inductance) are making the noise. Taller standoffs might help, or some other resistance from connector ground to top plate might "tune" the noise out. Or maybe a capacitor from phoenix connector star ground to top plate will shunt some noise out. Thanks for your help, I want to try this type of experiment next.(Edit: don't forget its quiet with the volume pot at the maximum travel, and this is a clue of some kind. Maybe thats proof its not B+ or EMF)


----------



## GeWa

For C6 in the power supply: would a 40µF ASC paper in oil cap be OK?

 Best regards


----------



## runeight

yes, as long as it has enough voltage rating. 400V is absolute minimum for this capacitor. 450V is better. The voltage here will be around 330V in some cases.


----------



## dcheming

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_too much gain_

 

 Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_dscheming, wIth no NFB the Bijou has a gain of about 25 into a high impedance load like an amplifier. This is probably too much for a preamp. You can try it, but the volume positions may be very difficult to manage.

 You can apply more NFB to reduce the gain, but the NFB in the Bijou is there only to handle difficult low impedance headphone loads. When driving high Z it's generally better to not apply too much NFB. Still, you can try it to see if you're ok with the sound of it._

 

Thanks for the info guys. I'll have to figure something else out to use as a preamp for my computer setup then.


----------



## GeWa

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_yes, as long as it has enough voltage rating. 400V is absolute minimum for this capacitor. 450V is better. The voltage here will be around 330V in some cases._

 

Well they are rated at 500V so, no problem there. Thanks runeight.

 Regards


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Grounding must be the problem. I tried another experiment, which was a different way of grounding the top plate, than connecting it straight to star ground. From the star ground connection on the phoenix connector, I put a 220K resistor on both amplifier boards and attached the other end to the top plate(I chose that value at random). This created some noise reduction and so maybe the boards hovering over the top plate(stray capacitance or inductance) are making the noise. Taller standoffs might help, or some other resistance from connector ground to top plate might "tune" the noise out. Or maybe a capacitor from phoenix connector star ground to top plate will shunt some noise out. Thanks for your help, I want to try this type of experiment next.(Edit: don't forget its quiet with the volume pot at the maximum travel, and this is a clue of some kind. Maybe thats proof its not B+ or EMF)_

 

Yes, the fact the the noise decreases when you have the volume all the way up says that this is likely a grounding problem somehow. What happens if you add another copper pipe? Just as a test.


----------



## amphead

Do you mean for more mass?
 I think, that I'll consider moving it to another chassis. An enclosed metal box with volume pot, input jack etc. mounted on the usual thinner front panel. Its tricky to troubleshoot this one, but others are having success with an enclosed metal chassis. If that doesn't cure it, then there would probably be an on-board component causing a problem. The scope might find the problem before I try this though.


----------



## runeight

Yes, a more massive ground. Just to see if this has any effect.


----------



## ericj

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Do you mean for more mass?
 I think, that I'll consider moving it to another chassis. An enclosed metal box with volume pot, input jack etc. mounted on the usual thinner front panel. Its tricky to troubleshoot this one, but others are having success with an enclosed metal chassis. If that doesn't cure it, then there would probably be an on-board component causing a problem. The scope might find the problem before I try this though._

 

Stupid question. i'm sure this has probably already been asked but i don't remember seeing an answer. I apologize if it's been answered already. 

 Tried running a wire from the frame of your volume pot and/or nfb pot to star ground?


----------



## amphead

Yeah, I hooked a wire around one of the two screws on the RK27 pot and soldered it and attached the other end to star ground about 10 days ago. Thanks Eric! Edit: how quiet is your amp with NFB turned off?


----------



## ericj

with no input audio, my bijou is very quiet no matter where the nfb pot is. So I feel kinda helpless to troubleshoot your issue - my build was a bit of a slam-dunk and thus i didn't learn any troubleshooting tricks from it.

 Edit: May be worth noting that my amp boards are screwed into a chunk of wood, and that the amp is quiet whether or not the mesh top/side piece is installed. The case is connected to star ground only via a wire connected to one of the screws holding down the power supply board, and the shell of my iec inlet is connected to mains earth, which is also connected to star ground.


----------



## amphead

Quote:


 May be worth noting that my amp boards are screwed into a chunk of wood, and that the amp is quiet whether or not the mesh top/side piece is installed. 
 

Damn right thats worth noting!  Thats my next test! I am going to put a stiff non-conducting top plate on the amp and see what that does. Don't know what material I'll use just yet. Remember when I mentioned to Runeight that my boards hovering over the stainless top plate might be the problem.  Instead of the top plate being a good ground plane, I think its acting like an antenna that sucks up noise and radiates it. What do you think Alex? Thats got to be it right?


----------



## ericj

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Damn right thats worth noting!  Thats my next test! I am going to put a stiff non-conducting top plate on the amp and see what that does. Don't know what material I'll use just yet. Remember when I mentioned to Runeight that my boards hovering over the stainless top plate might be the problem.  Instead of the top plate being a good ground plane, I think its acting like an antenna that sucks up noise and radiates it._

 

Could be. At this point, if i were you, I'd certainly be ready to try it.


----------



## runeight

amphead, yes i think we've narrowed this down some and we're pretty sure it's a grounding issue. you could be right about the ss plate. ss is not a good conductor and it could be doing the opposite of a ground plane.

 i think that the best solution would be something like a copper plate. 

 btw, where does your iec ground go?


----------



## amphead

Iec/earth straight to star ground. As soon as I install a sheet of hardwood plywood 11/32 on the top and remove the SS, I'll know what the verdict is in my case. If this works, then I'll just glue down a beautiful hardwood veneer to the top and polish it to a high gloss. If this doesn't work I'll try a copper top plate soldered to copper sides. Hope the first option works, and I will post results soon. thanks

 In the meantime a little conductivity trivia:
 Stainless = about 2 not good at all.
 Aluminum 59
 Brass 28
 Cadmium 19
 Chromium 55
 Cobalt 16.3
 Constantin 3.24
 Copper:
 Hard drawn 89.5
 Annealed 100
 Gold 65
 Iron:
 Pure 17.7
 Cast 2-12
 Wrought 11.4
 Lead 7
 Manganin 3.7
 Mercury 1.66
 Molybdenum 33.2
 Nichrome 1.45
 Nickel 12-16
 Nickel silver 5.3(18%)
 Phosphor bronze 36
 Platinum 15
 Silver 106
 Steel 3-15
 Tin 13
 Titanium 5
 Tungsten 28.9
 Zinc 28.2


----------



## holland

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Iec/earth straight to star ground._

 

Try disconnecting that. I believe that's your ground loop. Safety ground and post transformer ground isn't usually connected. You may need a ground loop breaker in there, but try it with it disconnected.


----------



## amphead

Thanks for the idea, but that was tried on the same day it was installed, to no effect......... I now have a cut piece of plywood on the top, and I am in the process of moving transformer and boards onto it.


----------



## GeWa

Found 4 of these in the mail today 
	

	
	
		
		

		
			





 Regards


----------



## amphead

Looks good GeWa! The side with knurled metal is the negative terminal.

 Well was there an improvement, when I listened to the amp with wooden top. Yes, but.............Not in the way that I was trying to accomplish. Was the noise the same as with the SS top plate? Yes. So I am still working on that. The wood does give a new and improved signature however with improved soundstage, detail and its even more musical, so it will stay. I am gluing some figured veneer to the top and will finish it to a nice gloss. The sound is gorgeous, with amp volume pot turned all the way up and source volume turned down. So eye candy and ear candy is there, but full functionality of the volume pot is not yet. I think that either copper foil/tape on the inside of the amp or another thick rectangular copper buss bar located close to the iec and making it a satellite star/buss ground attached to earth and copper pipe star ground, is the next step.


----------



## amphead

Glued a maple burl veneer to the top, after applying 3 coats of shellac and 3 coats of lacquer. Tomorrow I will buff the top and then install the transformer and the boards.


----------



## GeWa

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Glued a maple burl veneer to the top, after applying 3 coats of shellac and 3 coats of lacquer. Tomorrow I will buff the top and then install the transformer and the boards._

 

...and than you will post pictures? 
	

	
	
		
		

		
		
	


	




 Regards


----------



## amphead

Yes, but my digital camera was old and is now broken. I'll be getting another one, probably borrowed, because I prefer to spend on diy amplifiers.  Currently, I am polishing the veneer top.


----------



## amphead

Finished polishing the veneer top, and its a pearly white bleached figured maple. This contrasts with the transformer, boards and sides, for a nice effect. The transformer and boards have been mounted and I will wire everything tomorrow, after obtaining the copper buss bar.


----------



## GeWa

Slowly getting there. All the capacitors on the amplifier boards will be placed on the solderside. Still have to order the transformer, tube sockets and tubes though.

 Regards


----------



## amphead

Those must be Auricaps on the amp boards, good choice! Be cautious soldering the leads onto the photoflash caps. You need a good connection there.

 My amp is wired up once again, with a little bit of a change in the filament wiring. I twisted up 5 sets of wiring tighter than before and 4 of them are running through 1/2 inch diameter copper tubing, which has a wire running to star ground. This will act as a shield. Tomorrow I will solder another 1/2 inch diameter pipe near iec and this will be connected to star ground. No change to the noise yet, more work tomorrow. Still enjoying the sound with volume all the way up, and source all the way down. Pics soon.  Also I will run a wire to the body of the xformer to star ground as a test. Edit: I think I'll get some small diameter copper tubing that I can use as conduit/shielding for other areas of the amp. Earlier I said 2 inch diameter, but I corrected that its 1/2 inch.


----------



## GeWa

Those are indeed Auricaps, C6 will also be an Auricap. As far as resistors go, the ones that are directly in the signal path are Riken Ohm's al the rest are PRP. For the Photo Flash cap, I bended the legs in such a way that I can solder them directly on the pads and keeping the cap nicely level with the board. Think this is a safe way to do.

 For C2, can I use a non-polar type here. I have a few Elna Starget's laying around so I was wondering if I could use them there.

 Regards


----------



## ericj

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_For C2, can I use a non-polar type here. I have a few Elna Starget's laying around so I was wondering if I could use them there._

 

Sure. As long as they fit on the board.

 It's not that electrolytic capacitors do things differently with regard to having a polarity marked on them, it's that they have drastically lower DC voltage tolerance one way than the other way. using a non-polar electrolytic, which iirc is really two caps in one, is just more expensive and takes up more space - it'll behave the same with regard to the signal.


----------



## amphead

GeWa, I am not a fan of using too much solder, however it looks like the application of solder on the photoflash cap is too light in the photo.


----------



## GeWa

*amphead*
 The cap is not yet soldered, I just placed it in position to give you an idea of the end result. Sorry for the misunderstanding.

*ericj*
 Thanks for the clarification regarding C2

 Regards


----------



## amphead

That looks good GeWa! The advantage is that you will have a better mechanical connection, than soldering on leads.


----------



## Ferrari

After some hours busy with the drill-press, the top plate for my Bijou proto begins to get the form of how it finally should look like . Still lots of work to do, but here is the first pic.


----------



## GeWa

Not using the PCB's there aren't you? 
	

	
	
		
		

		
		
	


	



 Even nowhere near finished it looks good! (damn you Dutch people)

 Regards


----------



## Ferrari

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_Not using the PCB's there aren't you? 
	

	
	
		
		

		
			




 Even nowhere near finished it looks good! (damn you Dutch people)

 Regards_

 

I am using the proto PCB's, these PCB's are mounted on the inner side of the top panel. However, my build can be considered as partly P-P due to some off-board mounted MKP/PIO capacitors, including the output capacitors.


----------



## GeWa

Where do you get those big Audyn caps from?

 Regards


----------



## Ferrari

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_Where do you get those big Audyn caps from?

 Regards_

 

The Audyn MKP 330uF are from Speakerland (in the Netherlands), but unfortunately this type/value is out of production.
 Initially I got these capacitors for my other hobby -speaker builds-, but these capacitors are also excellent as output caps in tube apms.

 After extended listening test during the proto phase of the Bijou, I decided to put them in my amp. 
 They are really huge, but they sounds really huge too.


----------



## bhjazz

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Bijou proto begins to get the form of how it finally should look like . Still lots of work to do, but here is the first pic. 
	

	
	
		
		

		
		
	


	


_

 

FANTASTIC!!! Wow, that is gorgeous.


----------



## fordgtlover

Very nice - as usual - Ferrari

 I just got my PS up; 250V on the nose.


----------



## amphead

Nice looking build Ferrari.......Drool 

 Good job Fordgtlover! This is a great sounding amp and you are in for a treat. 

 Well, I found some 1/4 inch diameter copper tubing. I am going to shield all filament and signal wiring with this and solder wires to star ground from each one.


----------



## JamesL

Boo!
 Guess what I spent the past three hours doing?
 Buffalo + Bijou -
 I have absolutely no experience in amp-building, and i only just downloaded sketch-up, so it was a little tough getting those pieces in the smaller 230,280,40mm galaxy and getting familiar with reading schematic diagrams(sketch-up on the other hand was relatively easy to figure out), but I threw a design together. 
 I put everything onto a copper sheet to tidy things up, add more leniency, more streamlined, etc.. 

 Probably not the smartest idea to pair the buffalo and bijou though... 
 and I had no idea how easily a $170 kit could rack up to $800 preamp/amp/dac









 I'd like to build something like this, but I don't think it's a good idea just to leap into the diy world with a rather big project, without first building a foundation on simpler projects. 

 Also, a ~$230 amp module, and $325 Dac kit.. Maybe its not too wise? Though it'll have a loop-out, maybe 2-in-1 is not ideal for upgrading and experimenting, etc.. I stuck it in, cause that saves $100 on a separate case, and the two torroids help w/ aesthetics imo =P


 What do you guys think? Should i go ahead and go for it, or start with something smaller?


----------



## adamus

I would 100% start with something small. Why not start witha soha or millet max (non lethal voltages)


----------



## Ferrari

JamesL, whether it’s a good idea or not is entirely depends on your skills in electronics and experiences with DIY. Extreme care should be taken especially when it concerns an amp of this nature, with potentially lethal high voltages of more than 300V in certain parts of the amp. Making a sketch is totally different than making a working amp (or trouble shooting the amp as you can read in the last 10 pages of this thread.
 So you are correct that it’s not wise just to leap into the DIY world with something like this.


----------



## amphead

JamesL, while on the one hand I applaud your enthusiasm, which is a very important part of the hobby, High Voltage is something to be studied carefully before getting your feet wet(pun intended). It must be approached slowly and usually with the help of a mentor. Many have been self-starters as well, but you really need to tread carefully first. I totally agree with what Ferrari has said. On the other hand, if you start from a simpler design and move up to the more complex designs carefully, you can get where you want to go. Edit: that said, many of us in the diy community have received a substantial electrical shock at least once. In my case it was many years ago working on a Marshall amplifier, and I am lucky to be alive(defibrillation and knocked to the floor). Needless to say I don't prefer to repeat that experience. Be safe!


----------



## fordgtlover

Good news. My Bijou is all up and running.

 All is good. I just tried it using my iPod as the source before I move it inside. I won't comment on sound until I have had it running some music from a decent source into my K701.

 It;s temprorarily mounted on a board, so it is nothing to look at, but I'm sure happy that it worked first time.

 Cheers


----------



## JamesL

Heh.. thanks
 Anyways, I'll start off with a starving student, maybe a ppav2 later.

 I've done half a mini3 last winter and left it home before I went back to school, but I don't think I really got a lot out of "pcb stuffing." Thats one reason I don't want to go ahead and do a millet max or soha. I think they both leave little to creativity and experimentation.. plus, I don't know what I'd do after spending $200 building it... would a well-built amp be able to sell for it's value in parts?

 I just bought a handful of resistors, caps, leds, pots, breadboard, 9v battery, and a multimeter to kind of experiment with, so maybe I can get a better understanding of how electricity flows and what each component does.


----------



## jamess71

sorry


----------



## runeight

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_Good news. My Bijou is all up and running.

 All is good. I just tried it using my iPod as the source before I move it inside. I won't comment on sound until I have had it running some music from a decent source into my K701.

 It;s temprorarily mounted on a board, so it is nothing to look at, but I'm sure happy that it worked first time.

 Cheers_

 

yes, good news. I'll look forward to your listening impressions.

 Good job on getting it to work first time. The amp _should _work first time, with some care in building it.

 Now we just have to help our friend amphead to find his buzz problem and I will be a lot happier.


----------



## fordgtlover

^

 And thanks to you runeight for brining this to us and your support.

 Early listening impressions are very positive. This amp makes my K701 rock.


----------



## amphead

Thats awesome! Good to hear about your success, right off the bat. Post some pics when you can. Are you using NFB with K701, and if so how much?


----------



## amphead

Finished applying copper tape to the bottom of the wooden top. Buttoning it back up now. Odd that copper tape is used as a snail and slug barrier. Sometimes I improvise while troubleshooting, if I can't wait for shipping from an online source. Copper tape can also be applied to wiring along its length for shielding purposes. Copper tape would probably shield better than the aluminum foil shield on alot of shielded wire, because it conducts twice as well as aluminum.


----------



## fordgtlover

Not the world's best piccies, but you get the idea.

 Sounds great. I'm not so sure about the NFB. After about 1/3 of a pot turn using the K701 and i start getting noise. I have left it at the point just before noise starts?

 EDIT:

 Pictures removed so as not to encourage others to build an uncased (unsafe) Bijou. I will post pictures once mine is safely cased up.


----------



## amphead

Very nice! Until you have it cased up, you won't be getting a large enough ground sink to shunt noise to ground.

 So I installed the copper tape on the bottom of the wooden top and ran one wire to the center of the copper foil/tape from star ground. The listening test revealed a loud 60hz hum, but no buzz. Turning the volume all the way up got rid of the hum but............10 minutes into listening everything went dead. No heaters. The fuse checked good. Hmmmm............That happened at 3AM, so rather than work on High Voltage in the wee hours, I went to bed. Now to check floating secondary voltage on the xformer. You know the drill.


----------



## runeight

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_Not the world's best piccies, but you get the idea.

 Sounds great. I'm not so sure about the NFB. After about 1/3 of a pot turn using the K701 and i start getting noise. I have left it at the point just before noise starts?_

 

What kind of noise is it?


----------



## amphead

Heaters back up again. Cold solder joint at the transformer that came apart. The 60hz hum is there, as well as being louder. Theres probably a ground loop from copper tape/foil to some other point instead of the single point that I created. Theres a chance that the 1/4 inch copper tubing/shielding on the heaters, doesn't do well with the copper tape on the bottom of the wooden top. I am going to remove the tubing next.


----------



## runeight

good to hear that news about the heaters. 
	

	
	
		
		

		
			





 MHO is that the heater wiring is not a cause of the noise. I think that returing the heaters to simple twisted wire will be a good thing to do.

 The noise that you hear is PS noise (120Hz and harmonics buzz). I still think this is a ground problem. 

 So, if you can make a good star ground to the foil, this should be the best configuration.


----------



## fordgtlover

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_What kind of noise is it?_

 

I think it's some kind of radio interference - it's like a repetitive gurgling sound.


----------



## amphead

Well, my grounding set-up at the moment with copper tape on the bottom of the wooden top, separate copper pipe star ground and twisted heater wire against the bottom of the board, are a great example of what not to do with the Bijou. This created the loudest 60hz hum yet, by about 4 times. 
 Not to worry, I will remove the copper pipe star ground tomorrow and do a new star ground onto the copper tape. If that doesn't work, the copper tape must go. It is an insanely noisy config.  Then I would consider putting the amp in an aluminum amplifier enclosure.


----------



## mwofsi

amphead, how about the old Soha trick of either connecting or disconnecting
 Star Ground to Mains Ground?


----------



## runeight

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_I think it's some kind of radio interference - it's like a repetitive gurgling sound._

 

Right. Given the open configuration of your amp, this could easily be EM noise.

 However, check the NFB connections to make sure that left channel output goes back to left channel input, etc.


----------



## fordgtlover

thanks runeight. I have checked the connections - all good.

 I'm fine with leaving the NFB at its current position. The amp sounds great. I'll worry about this when I case it up.


----------



## runeight

ok


----------



## amphead

After a little digging through my storage closet, I found 2 aluminum chassis's. Both are the same size about 20 x 16 x 1 and1/2 inches. They are gold anodized and have an iec cutout at the back. They don't have a top or a front panel, but I am going to turn one upside down on the other. The new amp dimensions will be 20 X 12 X 3 inches after I cut it down. I'll create a front panel out of 3/16 plate aluminum. This will be a roomy chassis that allows for lots of xformer and board separation, while not being overly large. Edit: instead of turn one on top of the other, there will be a top aluminum plate. This will be a narrow height with tubes and transformer coming through the top plate. The caps/tube being tall on the PS means that there will be a mod allowing for those too.


----------



## fordgtlover

Does the C6 cap need to be 250V? The voltage appears to be 125V before the C5, C6 caps. 

 The reason for my question is that I have some 200V caps I would like to try in C6.

 I'm assuming this is fine.


----------



## Ferrari

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_Does the C6 cap need to be 250V? The voltage appears to be 125V before the C5, C6 caps. 

 The reason for my question is that I have some 200V caps I would like to try in C6.

 I'm assuming this is fine._

 

If you mean the bypass cap C6 at the output of the Biijou amp board: Yes !


----------



## fordgtlover

Ferrari, is that yes it must be 250V ?


----------



## Ferrari

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_Ferrari, is that yes it must be 250V ?_

 

Yes, you can use caps rated at 200V here (sorry for my short answer! 
	

	
	
		
		

		
			





).
 At this position it doesn't really need caps rated at 250V or higher. But on the other hand don't use caps rated at 160V or lower.


----------



## fordgtlover

^

 Thanks 
	

	
	
		
		

		
		
	


	




.


----------



## amphead

Mistakenly, I said my chassis was 20 X 12 X 1 and 1/2. It is actually 17 X 12 X 1 and 1/2. I'm in the process of mounting the aluminum top plate, that was cut today. I also had a piece of 1/4 inch aluminum plate cut for the front panel, which will be attached last after drilling for power switch, pots and input jack.


----------



## fordgtlover

How critical is the value of the C6 amp bypass cap? I've got a few different caps I would like to try in this position to determine if they make a difference to the SQ. I can go one of two ways, either bypass the existing 1uf cap with something smaller (I have a few 0.22uf) or replace the existing cap to make up a value close to 1uf.

 Has anyone been tinkering with these caps at all? Does anyone have any thoughts on this?

 BTW - I'm not trying to 'fix' any deficiencies in the Bijou, I'm mainly curious about how the caps impact on SQ.


----------



## Ferrari

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_How critical is the value of the C6 amp bypass cap? I've got a few different caps I would like to try in this position to determine if they make a difference to the SQ. I can go one of two ways, either bypass the existing 1uf cap with something smaller (I have a few 0.22uf) or replace the existing cap to make up a value close to 1uf.

 Has anyone been tinkering with these caps at all? Does anyone have any thoughts on this?

 BTW - I'm not trying to 'fix' any deficiencies in the Bijou, I'm mainly curious about how the caps impact on SQ._

 

Personally, NO electrolytics at the output of an amp for me. Even Black Gate Voodoo couldn't change anything.
 Here are a couple of types I have tried out so far.


----------



## regal

How do you like the 330uF Audyncaps?


----------



## Ferrari

To my ears, the Audyncap MKP 330µF is a huge step forwards comparing to generic electrolytics in terms of accuracy, resolutions, transparancy and extended but controlled bass. It does nothing spectacular with the music, just let the music (more or less) in its own value. I'm not sure if I'm going to put a smaller cap (Mundorf Silver Oil, Obbligato Film/Oil or Teflon) in parallel, and if I do... which one (?). Hopefully I will be able to decide that at some point in time, after extended listening test.

 However, generic electrolytics does its job as DC blocking very well and... if people are happy with the results, just keep that!


----------



## amphead

I'll go out on a limb, and say that most film caps are going to sound better than electrolytics as output caps. However, if you are going to use electrolytics, the Rubycon photoflash are quite good. And otherwise probably the Panasonics in the BOM are a good place to start. How good will depend on my results with the new chassis.  Edit: I thought of an inexpensive way to put feet on this chassis. I have a copper pipe one inch diameter, that I used as a buss bar, and I'll cut four pieces, file them flat on top/bottom and epoxy wooden dowels in for mounting.


----------



## ericj

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I'll go out on a limb, and say that most film caps are going to sound better than electrolytics as output caps. However, if you are going to use electrolytics, the Rubycon photoflash are quite good. And otherwise probably the Panasonics in the BOM are a good place to start._

 

The CDE caps i ended up using sound quite good to my ears after burning in the amp as well. But I'm not a student of capacitor sound by any stretch of the imagination. 

 I can't figure out what about photo flash caps is supposed to make them good for audio. Near as i can tell they're simply designed to withstand rapid discharge without major degradation. 

 My suspicion - and you'll have to forgive my cynicism - is that they are simply one of the few possible ways to spend a whole lot of money on a large high voltage cap, and nothing sounds better than money, right?


----------



## regal

The Rubycon's are made by the same parent company as Blackgate, I suspect that is part of it. They may have a lower DCR?

 I doubt anyone has done an A-B vs the Panasonics.
 The Audyn is tempting however, especially since I am only using 600 ohm phones with this.


----------



## ericj

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_The Rubycon's are made by the same parent company as Blackgate, I suspect that is part of it. They may have a lower DCR?

 I doubt anyone has done an A-B vs the Panasonics.
 The Audyn is tempting however, especially since I am only using 600 ohm phones with this._

 

One of the defining characteristics of capacitors is that their DC resistance is effectively infinite. 

 equivalent series resistance is another matter. 

 But i doubt that the photoflash caps are especially low ESR. I'm sure they've concentrated more on having it not blow up when suddenly discharged.


----------



## amphead

The only reason I used the photoflash, is that they aren't too expensive, about $7.00 each and sound really good. When I think of the description "fast cap" for other types, the fact that they discharge fast, can't be a bad thing in terms of SQ. There was an article on the web, about them being used with the first OTL Futterman, which was another reason I decided to try them, and I do like them.


----------



## ericj

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_The only reason I used the photoflash, is that they aren't too expensive, about $7.00 each and sound really good. When I think of the description "fast cap" for other types, the fact that they discharge fast, can't be a bad thing in terms of SQ. There was an article on the web, about them being used with the first OTL Futterman, which was another reason I decided to try them, and I do like them._

 

Still more expensive than the panasonic caps - the most expensive of which is $5.11. 

 The rubycon photoflash parts I've seen linked to on ebay here were closer to $20/ea. Right now the cheapest of acceptable ratings (400uf 330v) is about $12/ea. 

 Futtermans are traditionally DC-coupled - meaning no output caps or transformers. Of course, not all of them are really all that stable with regard to the DC offset at output - often the operating point of the tube seems to wander no matter how hard you try to nail it down - so, sometimes they have an output cap anyway. 

 As for being fast - all capacitors can discharge in a major hurry. What's unique about photo-flash caps is that this doesn't do them severe damage. If you read the datasheets, they're rated for a specific number of flashes - some of them as little as 1000, some more than 10,000. 

 The usual qualities looked for in electrolytics for audio coupling purposes are low esr and low leakage. A cap with a very low ESR charges very fast - putting a heavy instantaneous load on the power supply that services it - and this isn't a particularly important feature in flash service, since the power supply is relatively limited anyway. I'm not saying that photoflash caps have a relatively high ESR, but the datasheets don't say one way or the other, so until someone with an ESR meter tests a batch of them, we don't really know. 

 I'm not saying they're bad, I'm just saying i can't find a reason to believe they should be unusually good.


----------



## amphead

Quote:


 Futterman himself employed this strategy in the last bunch of amps that he built; he used photo-flash caps because of their high speed. 
 

That was what I read at this link:
Audio Asylum Thread Printer

 Apparently the vendor that I used on ebay has decided to only sell the 410uF at 300v in a 10,000 lot for $5000.00. Go figure.

10kx RUBYCON STROBE PHOTO FLASH CAPACITOR 410UF 300SV - eBay (item 7584355807 end time Jun-11-08 11:53:23 PDT)


----------



## regal

which NOS 6Dj8's are people liking in this amp?


----------



## ericj

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_That was what I read at this link:
Audio Asylum Thread Printer_

 

Futterman lived in the dark ages. In the 70's, I'm sure the photoflash caps were about as good as it got for electrolytics. 

 But capacitors have come a very long way in the last 10 years, let alone 30. I'm quite sure that the cheapest electrolytic manufactured today is faster than the best photoflash manufactured 30 years ago.


----------



## Ferrari

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_which NOS 6Dj8's are people liking in this amp?_

 

Have been running Siemens E88CC/gold pins for a while, but now I settle on 6N1P.


----------



## regal

What about the Ecc99 driver tubes, it seems there aren't any NOS of this variety or would they be called another name?


----------



## ericj

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_What about the Ecc99 driver tubes, it seems there aren't any NOS of this variety or would they be called another name?_

 

The ECC99 is JJ Tesla's version of the russian 6n6p, which you can get quite cheaply in NOS form - mostly from ebayers in former russian states, though. 

 It's generally recommended to use the 6ca4/ez81 rectifier tube when running 6n6p's due to their slightly higher plate current. 

 The heater secondary of the Hammond 270DAX can handle 2x 6n1p at 600ma each, 2x 6n6p at 800ma each, and 1x ez81 at 1000ma without problems. The 6n6p-i (computer-grade 6n6p?) has a 1000ma heater, so probably can't be mixed with 6n1p or 6h30 without adding an additional filament transformer, but can be mixed with more normal 6dj8 parts. 

 I haven't heard the ecc99 but my 6n6p's sound great after burn-in. 

 If you don't want to wait for shipping from the ukraine, latvia, etc; PM me, i have half a dozen spare 6n6p and i could mail you a pair for not a whole lot of money.


----------



## amphead

Created the mounting points for the top plate today. A few other things need to be done before the top plate gets mounted. I need to cut out the area for the xformer to come through, as well as for the PS and the amp board tube holes. Tube holes through aluminum, not as daunting a task as through stainless steel. After that, the fastening points for the front control plate.


----------



## Ferrari

To answer a couple of questions I've got by email regarding using 250V-0-250V transformer instead of 260V-0-260V transformer in the PS of the Bijou, I have made a quick measurement with a prototype PS using 250V-0-250V transformer with EZ80 rectifier. I decide to post the answer here as well so that it maybe usefull for other builders in Europe (or other part in the world) where 260V-0-260V transformer is difficult to source, while 250V-0-250V transformer is much easier to find.

 1. If the Bijou functions well with 250V-0-250V transformer?
 => yes, without any problem or audible bad effect.

 2. What is the maximum output voltage of the PS when 250V-0-250V transformer with EZ80 rectifier are used?
 => the answer can be found the the picture below.
 Note that the PS is loaded with an indicator tube (bottom left corner) and the trimpot on the PS is at its maximum (full clockwise). 








 The the output voltage of the PS is ~240V DC. On my current implementation, an EZ81 as rectifier is used instead of EZ80, the output voltage of the PS is close to 250V (with 250V-0-250V transformer of course).


----------



## regal

For the 270 transformer what is the primary 110V wiring scheme, I can't find it on Hammond's website and nothing is marked on the transfomer.


----------



## TimmyMac

Quick question before I make any decisions about my casing solution. If I mount the transformer (270DAX) on the top panel of the case, and also mount the tubes up top, will there be any problems with 60Hz vibration from the transformer causing noise in the tubes through vibration/microphonics?


----------



## ericj

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_For the 270 transformer what is the primary 110V wiring scheme, I can't find it on Hammond's website and nothing is marked on the transfomer._

 

the black wires go to 110v mains. 

  Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_Quick question before I make any decisions about my casing solution. If I mount the transformer (270DAX) on the top panel of the case, and also mount the tubes up top, will there be any problems with 60Hz vibration from the transformer causing noise in the tubes through vibration/microphonics?_

 

the transformer will not physically vibrate. with proper routing of well-twisted heater wires you shouldn't have any electromagnetically-induced hum either.


----------



## TimmyMac

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_the transformer will not physically vibrate. with proper routing of well-twisted heater wires you shouldn't have any electromagnetically-induced hum either._

 

Thanks. To mount them on the surface I will need to run wire from the PCB pads up to the tube sockets. Any preferred gauge for this? I was planning on going 20ga for the heaters, 26ga for the other stuff except 22ga 600V for the rectifier -- this is correct, yes?


----------



## ericj

Actually if you mount the capacitors on the bottom side of the board, you can mount the tube socket both directly to the pcboard and bolted to the chassy. I believe there are pictures of this method somewhere in the thread.


----------



## dBel84

bottom of board







 top of board






 ..dB


----------



## miky

I need a 230v transformer. Which would you recommend - the r-core from HK (R0080-036 Audio Catalog ) or the Hammond 370 DAX?


----------



## dBel84

they have both been used equally successfully in the Bijou, choose whichever is easiest to source and combine with other things that you may need..dB


----------



## amphead

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_Thanks. To mount them on the surface I will need to run wire from the PCB pads up to the tube sockets. Any preferred gauge for this? I was planning on going 20ga for the heaters, 26ga for the other stuff except 22ga 600V for the rectifier -- this is correct, yes?_

 

Yes on the 22ga and 20ga and I would still stick with 22ga for the other stuff vs 26ga. While 26ga may work for signal, it is physically very light and possibly less durable.


----------



## fordgtlover

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_The ECC99 is JJ Tesla's version of the russian 6n6p, which you can get quite cheaply in NOS form - mostly from ebayers in former russian states, though. 

 It's generally recommended to use the 6ca4/ez81 rectifier tube when running 6n6p's due to their slightly higher plate current. 

 The heater secondary of the Hammond 270DAX can handle 2x 6n1p at 600ma each, 2x 6n6p at 800ma each, and 1x ez81 at 1000ma without problems. The 6n6p-i (computer-grade 6n6p?) has a 1000ma heater, so probably can't be mixed with 6n1p or 6h30 without adding an additional filament transformer, but can be mixed with more normal 6dj8 parts. 

 I haven't heard the ecc99 but my 6n6p's sound great after burn-in. 

 If you don't want to wait for shipping from the ukraine, latvia, etc; PM me, i have half a dozen spare 6n6p and i could mail you a pair for not a whole lot of money._

 


 Great info ericj - thanks


----------



## miky

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_they have both been used equally successfully in the Bijou, choose whichever is easiest to source and combine with other things that you may need..dB_

 

Thanks


----------



## Ferrari

Have been tinkering with the heater supply of my Bijou a bit...
 My 6.3V DC @5A power supply based on LM338K is up and running, ready to try out in the weekend.


----------



## amphead

Quote:


 Have been tinkering with the heater supply of my Bijou a bit...
 My 6.3V DC @5A power supply based on LM338K is up and running, ready to try out in the weekend. 
 

That should be nice and quiet. If you have the time to A/B with AC heaters, I would be interested in the difference in your sound.


----------



## ericj

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_That should be nice and quiet. If you have the time to A/B with AC heaters, I would be interested in the difference in your sound._

 

With careful routing and tightly twisted (like with a drill) heater wires, AC heaters should be inaudible. 

 I sure can't hear my AC heaters. 

 You should route heater wires away from signal and ground wires, crossing at a 90 degree angle where they must cross. Do not run heater wires under circuit boards. Keep the heater wires close to the metal of the chassis if you have a metal chassis. 

 i know that you know this, amphead, just stating it for anyone who's following along. DC heaters shouldn't ne necessary but might work better for some people, or some people may just prefer it.


----------



## bhjazz

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_bottom of board

 top of board

 ..dB_

 

Nice work. Jam thos babies against the top plate and let the glow out, yo!

 This lends itself to a hundred more case design ideas for me. Every time I think I can rough out the beginnings of one I see another nice idea like this. I like it. I very much want to have the tubes stand on their own and be able to stick out of the case by themselves. I'm sure with some careful soldering its pretty doable.

 Then I have to start over. 

 Thanks for the excellent example pics, dB!


----------



## Ferrari

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_With careful routing and tightly twisted (like with a drill) heater wires, AC heaters should be inaudible. 

 I sure can't hear my AC heaters. 

 You should route heater wires away from signal and ground wires, crossing at a 90 degree angle where they must cross. Do not run heater wires under circuit boards. Keep the heater wires close to the metal of the chassis if you have a metal chassis. 

 i know that you know this, amphead, just stating it for anyone who's following along. DC heaters shouldn't ne necessary but might work better for some people, or some people may just prefer it._

 


 Well, If you can't hear AC heaters and think that DC heaters shouldn't be necessary, then do it that way!

 Not that I think that AC heaters are bad or something, I prefer NOT to run AC wires back and forth in my amp (not particular in this amp but in general, for many years). Also I have the resources and all parts on hand... and I am busy with the construction of my β24 at the moment, so I spend a couple of hours on this simple 6.3V PS (drilling, tapping work on heatsinks...).
 Some quick measurements do showing different (improvement) on the noise spectrum when AC - unregulated PS - regulated PS is used.


----------



## fordgtlover

I've been looking to try out some different tubes, but I'm a bit confused. Hopefully someone can give me the heads up.

 The question relates to the 6922 = 7308 = ECC88. While I understand that they are all interchangeable, the heater current does vary between them.

 Do I need to modify the cathode resistor (R2) to roll any of this family of tubes?


----------



## regal

no


----------



## fordgtlover

^
 Thanks


----------



## amphead

Well, I don't know whether DC or AC heaters sound best with the Bijou. I have heard both arguments in the past. AC heaters sound more lively. Also, I had heard others who swear by the sound with DC heaters. In my case, heaters may or may not have been creating any noise at all, but I won't know until I finish my aluminum enclosure. Tonight, I will mount the front control plate, and tomorrow I cut out an opening for the xformer. I will drill holes in the four corners and then cut a line to each with an unmounted hacksaw blade and then clean up with a file.


----------



## fordgtlover

The 6DJ8/ECC88 tube is rated for 130V. 

 Can some confirm that this is too low for the Bijou, and therefore can't be used.

 Cheers


----------



## ericj

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_The 6DJ8/ECC88 tube is rated for 130V. 

 Can some confirm that this is too low for the Bijou, and therefore can't be used.

 Cheers_

 

Each section of the tube sees about 90v iirc.


----------



## regal

I have read this entire thread in preparation for the build.

 I am really dissapointed in the lack of safety presented by some of these builds.
 We have Bijou's in cardboard boxes others wide open with no enclosure.

 Folks I have seen what HV DC current can do to people and it ain't pretty. We have people building these and seeing these pictures thinking it is OK, we are setting a bad example.

 If one person ends up dead or in the hospital do you think Runelight will share another design?

 I don't mean to be a prick but lets just make sure that any new builder understands that this amp must be enclosed.


----------



## amphead

Yep, there's no substitute for safety when working with High Voltage. Thanks for your post Regal!


----------



## fordgtlover

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I have read this entire thread in preparation for the build.

 I am really dissapointed in the lack of safety presented by some of these builds.
 We have Bijou's in cardboard boxes others wide open with no enclosure.

 Folks I have seen what HV DC current can do to people and it ain't pretty. We have people building these and seeing these pictures thinking it is OK, we are setting a bad example.

 If one person ends up dead or in the hospital do you think Runelight will share another design?

 I don't mean to be a prick but lets just make sure that any new builder understands that this amp must be enclosed._

 

Excellent point - I've removed my pictures (as one of the offenders).


----------



## regal

Thanks Ford, I mainly wanted to bring it up for Newbies to understand the dangers.


 On a lighter not I have been thinking about output cap possibilities. I am kicking around 4 possibilities. Keep in mind this is for 600 ohm Sextetts:

 1. BlackGate VK 150 uf $20x2
 2. Solen PPA 120 uF $35x2
 3. Jensen audio grade 100+100 uF wired in parralell to give 200 uF $50x2
 4. Ebay motor run 100 uF (may be too large for my case. $12x2


 With the sextetts all of these will have a corner freq under 4hz. I am not adding the NFB circuit. Also C1, C3,C4 will all be Solen's, so I am just leaning toward option #2.


----------



## dBel84

Regal: I appreciate your sentiments that HV is dangerous and that anyone who considers building the Bijou be aware and take due caution when building the amp. However, I disagree with the opinion that anyone is under the impression that the Bijou can be built without a decent / protective enclosure. [ cardboard boxes excluded ]The images people have posted are generally the initial breadboarded version and most if not all people I know, build amps in this manner. This is where the trouble shooting begins if needed. Posting images of a well breadboarded amp not only shows the less experience how to go about taking the necessary precautions, which is in itself a time consuming exercise, and hopefully emphasizes the importance of taking such necessary steps in order to test the amp safely. 

 Discussions such as these are also useful as a reminder to folk that safety is imperitive when working with electricity as a whole. ..dB


----------



## hershann

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I have read this entire thread in preparation for the build.

 I am really dissapointed in the lack of safety presented by some of these builds.
 We have Bijou's in cardboard boxes others wide open with no enclosure.

 Folks I have seen what HV DC current can do to people and it ain't pretty. We have people building these and seeing these pictures thinking it is OK, we are setting a bad example.

 If one person ends up dead or in the hospital do you think Runelight will share another design?

 I don't mean to be a prick but lets just make sure that any new builder understands that this amp must be enclosed._

 

Mine's the one with the cardboard box - it was a trial layout and to make sure that everything works - in a apartment where I live alone. Once I've ensured that the device is working and after listening for a while, it is currently disassembled waiting to be put into the permanent (metal) enclosure.

 I am extremely careful with HV and uses thick gloves when testing voltage points without any metal on my body. When switched on - all components are fully enclosed except for the exposed tubes. I also carefully discharge the HV caps before I will touch the the PCBs and wires when tweaking.

 her shann


----------



## runeight

Gents, these are all good and important points about the HV. You know from the Bijou website that I take the HV seriously, having been whacked myself pretty badly over the years on a few occasions.

 I just ask that everyone use good, informed judgement about building this amp. It's designed to be as safe as possible, with as little exposure to the HV as possible. And if anyone is not comfortable around the HV (which could be deadly under the right circumstances) then please build one that will be more suitable for your situation. 
	

	
	
		
		

		
			





 Otherwise, when you get the Bijou working I think you'll like it!!!!


----------



## Ferrari

All the Bijou talk, time for Bijou tease...






 I don't think that I like it, I know that I like it! 
	

	
	
		
		

		
		
	


	



 Mine is taken apart to do the case work, so I have to miss it temporarily for a couple of weeks. But sure, it will be up and running again very soon. The only thing that I have overlooked on this build is the final weight of it.
 It was never on my mind to build a 10Kg(+) Bijou.


----------



## fordgtlover

^

 As usual Ferrari - very professional and sexy.


----------



## Ferrari

Quote:


  Originally Posted by *fordgtlover* /img/forum/go_quote.gif 
_^

 ... very professional and sexy._

 

eehhh... that's what I told my GF lately.


----------



## dBel84

fantastic work again, I am a fan of symmetry and I particularly like those tube surrounds from VT4C. 

 but next time post a pic of the GF instead  ..dB


----------



## Ferrari

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_...but next time post a pic of the GF instead  ..dB_

 

But then I'm in violation with Head-Fi rules. 
	

	
	
		
		

		
		
	


	



 Tubes p*o*r*n only is better, I guesse.



 (have to use the *** due to the automatic filter/censor at this place)


----------



## amphead

Quote:


 I don't think that I like it, I know that I like it!
 Mine is taken apart to do the case work, so I have to miss it temporarily for a couple of weeks. But sure, it will be up and running again very soon. The only thing that I have overlooked on this build is the final weight of it.
 It was never on my mind to build a 10Kg(+) Bijou. 
 

There is a chance that it will sound as good as it looks. 
	

	
	
		
		

		
		
	


	




 In my case, the front panel has been mounted, using some fancy machine screws for aesthetics. Probably no pics until I have a functional unit.


----------



## mwofsi

amphead, still dying to to know: when and how you've got those noise issues fixed.


----------



## GeWa

Just to inform you guys of my progress.
 In the attached image you can see the top and bottom side of my amplifier boards. Also my transformer (370DAX) and tubes where delivered today.
 Slowly getting there. 
	

	
	
		
		

		
		
	


	




 Regards


----------



## amphead

Quote:


  Originally Posted by *mwofsi* /img/forum/go_quote.gif 
_amphead, still dying to to know: when and how you've got those noise issues fixed._

 

The amplifier has been moved from the wooden enclosure to an all aluminum chassis. This is an attempt to get rid of any noise from my other setup. Once I have finished, I will know if its fixed. 

 Now that the front panel is mounted, I cut the opening for the xformer. Taking things a bit slow to avoid mistakes. The good news is that these surplus chassis cost me $5.00 plus $5.00 aluminum top. The bad news is that my stainless hardware to get a professional look costs me $20.00(flat head w/allen european mfg.). 

 Edit: looking good GeWa!


----------



## mwofsi

The Bijou's not really on my to do list (yet), but following you guys progress is still fascinating and I hope it goes well.

 amphead your efforts have been great and deserve better reward


----------



## amphead

If it would be your first venture into High Voltage/Tubes, then working up to it would be worthwhile. The Bijou, is an elegantly simple design, but with many of the issues that more complex amplifiers present.

 Just cut four 1 and 1/4 inch diameter copper pipe feet. These were fitted with epoxied-in hardwood dowel stock. These are an inch and one eighth tall. Polished the copper with 0000 steel wool to a nice shine. They get mounted onto the chassis tomorrow. They should provide a small amount of damping, but will contrast with the silver color of the aluminum for a nice effect. Maybe a copper accent elsewhere on the chassis to tie it all together.


----------



## amphead

Copper feet have been mounted, tonight I will cut the holes for the front control plate components. L/R volume, output jack and power switch.


----------



## fordgtlover

After having my Bijou for the past couple of weeks and very much enjoying it, I had started noticing a little graininess in some songs. After doing a bit of research I took a stab that it might have been because of the Philips 6922 that I was using. I picked up some early 1970s Sylvania 6922 tubes; these did the trick - graininess was gone. I also picked up, and installed, an EZ81 based on the suggestion posted here by runeight and ericj.

 This amp was sounding *very* nice. In fact I was just about to post how much I was enjoying it, when I sat down and turned it on - no sound through the left channel. After checking some measurements and some tube swapping, it seems that one of my 6N6P tubes is no longer working. Fortunately, I have already ordered some 6N6P-I tubes off ebay, but unfortunately they are coming from Ukraine. My last experience with postage from Ukraine was very slow (5 months).

 I hope that these tubes arrive in reasonable time so I can get back to listening to this lovely amp.

 On the bright side, I can start planning the case now. I hadn't done anything about casing up my Bijou because I kept distracting myself by listening to it. I also picked up some 1uf K40 capacitors on ebay last night, so I guess this also gives them time to arrive.

 Oh well... I look forward to listening to my Bijou again in a few weeks time.


----------



## amphead

Sorry to hear that. I know what you mean, because I am without Bijou tunes for a while until the new chassis is finished.


----------



## regal

is the heater wiring for the 6N6P-i the same as the 6N6P ?


----------



## Ferrari

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_is the heater wiring for the 6N6P-i the same as the 6N6P ?_

 

Yes, 6.3V heater connected to pins 4 and 5.


----------



## regal

Thanks, also I take it most are wiring the AC line-in ground to the star ground?


----------



## Ferrari

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Thanks, also I take it most are wiring the AC line-in ground to the star ground?_

 

 You can do that. Don't forget to isolate input connectors and headphone jack from the chassis.


----------



## regal

Is it possible to isolate the Alps R27 from the chassis?


----------



## Ferrari

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Is it possible to isolate the Alps R27 from the chassis?_

 

If the front panel -where the Alps RK27 is mounted- is non-metal like some Hammond, then is the Alps RK27 electrically isolated from the metal chassis part.

 But why should you want to isolate the Alps RK27 from the chassis, from electronics engineering point of view ?


----------



## regal

well the housing is continuous with the ground screw in the back, so I assumed you only want one ground path. But I checked for continuity between the housing and any of the pins and all the pins are isolated from the housing. 

 So I don't think it would need to be isolated.


----------



## TimmyMac

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_You can do that. Don't forget to isolate input connectors and headphone jack from the chassis. 
	

	
	
		
		

		
		
	


	


_

 

The schematic shows the headphone jack connected to star ground... should star ground be isolated from the chassis as well?


----------



## runeight

The star ground should be connected to the chassis to ensure a good ground plane for the amp.


----------



## TimmyMac

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_The star ground should be connected to the chassis to ensure a good ground plane for the amp._

 

Yes, I thought so.

 Anyone know an easy way to cut a 7/8" hole in 10ga steel for the tube sockets? I'm almost done with the casework and just waiting on the trafo to wrap this thing up.


----------



## willisv

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_Yes, I thought so.

 Anyone know an easy way to cut a 7/8" hole in 10ga steel for the tube sockets? I'm almost done with the casework and just waiting on the trafo to wrap this thing up._

 

I used a stepped drill bit for drilling my holes. You can probably find one at your local hardware store.


----------



## regal

Just fired my new Bijou, without the phones plugged in I get between 10 to 100 mV DC offset.

 When I plug in the phones it Zero's.

 Is this normal?


----------



## runeight

yes, it's normal. the cap is slightly charged on power up and the 10k resistor at the output should bleed it down fairly quickly. There is also a small leakage from the electrolytic that will make a small offset without the headphones. but once a low resistance to ground is inserted the offset drops because there is no significant source of current through the capacitor.


----------



## regal

Runelight thanks for all your help.


 My amp is now finish in stock form. I used film caps for everything on the amp board except the ouput cap with NFB deleted (AKG 600 ohm HP's.)

 The sound out of this amp is stunning. I have never heard upper midrange/treble this lifelike and accurate. This design of yours is truely outstanding.


----------



## TimmyMac

Quote:


  Originally Posted by *willisv* /img/forum/go_quote.gif 
_I used a stepped drill bit for drilling my holes. You can probably find one at your local hardware store._

 

Yeah, but it's $60.


----------



## runeight

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Runelight thanks for all your help.


 My amp is now finish in stock form. I used film caps for everything on the amp board except the ouput cap with NFB deleted (AKG 600 ohm HP's.)

 The sound out of this amp is stunning. I have never heard upper midrange/treble this lifelike and accurate. This design of yours is truely outstanding._

 

You're most welcome. Nice that you're up and running. The amp should sound better over time as the tubes break in. But, I'm very happy to hear that you like what it does now.


----------



## regal

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_Yeah, but it's $60._

 

I bought a pair at Harbour Freight for $18.


----------



## amphead

Regal, thats really fantastic to hear! Is your casework completely finished? If so, how about some pics. 

 TimmyMac, is there a Harbor Freight in your neck of the woods? Thats where I bought my step drill and its really the only way, other than a greenlee panel punch. Otherwise drill the largest hole near 7/8 and dress up the hole with a course medium roundfile on a drawn circle(tedious).

 I am drilling my top plate today. Took a 2 day break from the project after my drill grabbed an aluminum mounting block and spanked my thumb a few times. Just an abrasion.  Be careful! Don't work when you get tired.


----------



## TimmyMac

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I bought a pair at Harbour Freight for $18._

 

Hmm, wish I had one of those around. I guess I could ebay it and wait another week.


----------



## miky

I would like to compare different caps (C1, C3, C4, C6). What is the best way to connect them to PCB without soldering/desoldering?


----------



## Clutz

You could make a jumper cable and then solder each of them to the jumper cables until you decide what you want, and then put them in place. Or maybe get some SIP sockets and socket them.


----------



## Ferrari

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_I would like to compare different caps (C1, C3, C4, C6). What is the best way to connect them to PCB without soldering/desoldering?_

 

There are serveral way to do it, but one of the fastest way is to make use of short cables with clamps on both ends, common used in labs. Solder small pieces of resistor lead clips on the solder points of C1, C3, C4, C6 on the PCB. Then use cables with clamps on both ends to connect the caps to the PCB. During prototyping and experimenting with caps, I have been doing it in a similar way. Not very neat... but it makes removing/exchanging caps very fast and easy. (Be sure to try this in a safety work place, without kids playing around !!!).


----------



## miky

Thanks for your inputs! 
*Ferrari* nice idea


----------



## amphead

Good idea Ferrari!

 Installed the power switch and Neutrik output jack on the 1/4 inch aluminum front panel. Tomorrow the volume pots are going to be installed.


----------



## regal

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Regal, thats really fantastic to hear! Is your casework completely finished? If so, how about some pics. 

 ._

 







 Sorry my 2002 digital camera sucks inside (usually have to take things outside to photograph, too lazy today.)


 Specs (dedicated to 600 ohm Sextetts) :
 Par-Metals Enclosure 12x16x5"
 Amp boards - Solens for all caps except output 
 Output caps: Electrolyitc bypassed w/ KY42
 Russian 6922 & 6N6P
 NFB Delete

 Future upgrade:
 Z81 rectifier tube
 JJ ECC99's
 Amperex 6DJ8 biased to 5 mA
 VitQ interstage coupling caps
 Obbligato 100uF Output coupling caps

 But as it is now its the finest amp I have heard.


----------



## Ferrari

regal, good to know you like it.
 What are you using for C2, cathode bypass cap on the amp boards? Solen ?


----------



## regal

I forgot about those, they are the Muse Non-Polar Electrolytics. Goal is to find an LED when I bias up to 5 mA.


----------



## amphead

Thats beautiful Regal! The photo quality not withstanding. Looks like the Marantz version of the Bijou. 

 Well, I made the cutout for the xformer last night in the top plate. Installing the xformer tonight.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Thats beautiful Regal! The photo quality not withstanding. Looks like the Marantz version of the Bijou. 

 Well, I made the cutout for the xformer last night in the top plate. Installing the xformer tonight._

 

It really DOES look Marantz-like! Good eye!

 Regal, nice work...Looks like the silver contender!

 Ferrari: your's looks very clean and amazing as well. Those caps look pretty cool! Yow!

 Me? Well, I'm working a bit with FPE after making the world-wide search for a case. I have one option left for what I _really _want in a case, and if that falls through, then I'll move the idea to art on the front panel.


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Thats beautiful Regal! The photo quality not withstanding. Looks like the Marantz version of the Bijou. _

 

Exactly.


----------



## Ferrari

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_...
 Ferrari: ...Those caps look pretty cool! Yow!_

 

The look is not my main focus when selecting output caps, however cool looking caps are more than wellcome, to be honest. 
 I finally end up with ~400µF MKP/Oil after a long trial with many output caps combinations. This value (400µF) also allows using low impedance headphone like AKG K701 (my GF favourite) without bass suffering.


----------



## miky

I would like to try some of "premium" caps (Solen, Auricap, MultiCap RTX, Mundorf M-CAP Supreme, Sonicap Gen I, Clarity SA, and DynamiCaps). Do you have any recommendations for C1, C3/4, C6 and C2 (BG?)? 
*Ferrari* what kind of capacitors do you use for c5/6? I have AKG K701.


----------



## Ferrari

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_I would like to try some of "premium" caps (Solen, Auricap, MultiCap RTX, Mundorf M-CAP Supreme, Sonicap Gen I, Clarity SA, and DynamiCaps). Do you have any recommendations for C1, C3/4, C6 and C2 (BG?)? 
*Ferrari* what kind of capacitors do you use for c5/6? I have AKG K701._

 

That's going to kill your wallet mate. 
	

	
	
		
		

		
		
	


	




 To be honest, I don't know all the caps from your list, only Solen, Auricap, DynamiCaps and Mundorf M-CAP Supreme are well known by me. I don't regard Solen MKP as "premium" cap. It's a step up from ordinary Wima, BC... MKP at a very reasonable price but nothing special. Auricap and DynamiCaps are clearly a bigger step up and are worth to try, you can't go much wrong with these caps. 

 My preference is Mundorf Silver/Oil, an excellent all-rounder to my ears. The only downturn is (may be) the price, but if you can afford it, you should give it a try. For C2, you can use BG NX but it should be tough to get it fit the board.
 Note that this is my personal experiences/opinions, other people might have totally different opinions.

 Personally, I use Audyn MKP for C1 and C5 (I need much capacitance at these positions) and Obbligato MKP/Oil for C6. These are simply the caps I accidentally have on hand.


----------



## miky

Thank you!
  Quote:


 That's going to kill your wallet mate. 
 

I don’t mean to try all of them. 
	

	
	
		
		

		
		
	


	



 What you say about Russian PIO/Teflon (K42Y-2, FT-2 etc.)?

 Does someone have some experience with Sonicap Gen I?


----------



## Ferrari

Russian PIO? It depends on which type you are talking about. 

 K42Y-2 PIO (metalized paper in oil) is overhyped in an other thread here at HF, very cheap and widely available on eBay.
 To my ears it's nothing special, surely not a capacitor that I would put in my amp. Yes, it pumps the bass up (good for bass head), but the remaining audio band sounds quite dirty, poisoned mid-range and highs. Details and resolulions are really disappointed.
 Alcheapo K42Y-2 PIO is clearly a big step down from K40Y-9 PIO.

 K40Y-9 (metal foil + paper in oil) is a different story. The sound is much more neutral and smooth. (not that dirty, poisoned sound of K42Y-2). Considering the price, it's a good bargain for audio applications.

 About Russian FT3 and K72 Teflon caps? I have posted my opinions about these caps here.


----------



## regal

Ferrari, what do you think of the big 100uF motor run oil can capacitors like you see on ebay (some are sprague.) I only need 100 uF with my 600 ohm phones and am tempted to try these.


----------



## Ferrari

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Ferrari, what do you think of the big 100uF motor run oil can capacitors like you see on ebay (some are sprague.) I only need 100 uF with my 600 ohm phones and am tempted to try these._

 

Personally, I have not tried motor run oil capacitors yet, so I can't comment on this.
 From what I read at diyAudio.com, tubes lovers seems to like motor run oil capacitors very much.
 If I can remember, n_maher (a HF member) has put 200uF motor run oil capacitors in his amp, so I think that he can help you.


----------



## bhjazz

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_The look is not my main focus when selecting output caps, however cool looking caps are more than wellcome, to be honest._

 

I agree. It's just that they were so...BIG!


----------



## Ferrari

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_I agree. It's just that they were so...BIG! 
	

	
	
		
		

		
		
	


	


_

 

Those 330µF polypropylene caps are initially intended to use in speakers filters (speakers builds is my other hobby for years).
 Yes, they are BIG for an tube amp... but as long as they are sounding BIG too, then that is no problem at all for an DIY audio nut like me. I will find a way to make them fit.


----------



## n_maher

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_If I can remember, n_maher (a HF member) has put 200uF motor run oil capacitors in his amp, so I think that he can help you._

 

I rather like them as coupling caps, although they are massive. My current amp uses 2 x 100uF caps on each output (in parallel) and each cap is 2.5" in diameter and 4-3/4" tall. 






 They are the 4 caps across the front.


----------



## dBel84

I would like to try these on for size 
	

	
	
		
		

		
		
	


	









 ..dB


----------



## amphead

If I could fit those in my budget, there would be room. 

 Mounting the amp boards in the chassis tonight. Then the PS board. Getting closer.........


----------



## runeight

amphead, i don't know how much longer i can stand the tension.


----------



## pabbi1

Has anyone built the Bijou balanced? I remember it having 'too much gain' in that configuration, but I was told the same with The Milletmax (not at all the case). 

 Toward that end, I have a few questions - would I just use the stock psu boards and two trannies, or any way to consolidate to one board and tranny? Anyone built a version with a Joshua Tree attenuator, or other 128 step ladder? If I have to use two psu / boards, has anyone built a version with seperate psu and amp boxes?

 I would definitely be using this with Senns, so any tuned BOM (especially resisters, diodes and caps), including tube recommendations? 

 P2p is not an option for me.


----------



## runeight

You can build balanced and there will be a lot of gain, but this may be quite alright for what you're listening to.

 The simplest way would be to double everything. The PS is pretty tightly designed to handle one stereo amp. It will be hard to make it do more than this without some redesign.

 You might get away with a single transformer if you can find at least 150mA on the HV secondary and about 6.3V/6A for the heaters (or two separate 2.5-3A windings). I haven't looked, but there could be a Hammond or RCore that fits these specs.

 Many builders are sub'ing various parts, but the main thing for Senns would be to eliminate the NFB entirely. This is described on the website.


----------



## amphead

You would be in for a treat Pabbi. Definitely a worthwhile struggle to build a balanced Bijou. If you make the layout/component selection right, its a real contender. Edit: Its a short drive to Austin from where you're at. 
	

	
	
		
		

		
		
	


	




 Installed the amp boards, so the cutout for the PS board will be done tonight. Thanks Runeight.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_You would be in for a treat Pabbi. Definitely a worthwhile struggle to build a balanced Bijou. If you make the layout/component selection right, its a real contender. Edit: Its a short drive to Austin from where you're at. 
	

	
	
		
		

		
		
	


	




 Installed the amp boards, so the cutout for the PS board will be done tonight. Thanks Runeight. _

 

Austin is a scary place - with runeight and luvdunhill (maxing out KGSS and revamping the Blue Hawaii), I am not sure my wallet can stand the pressure.

 So, in general, in what ways is the Bijou better than the MillettMax - is it simply a function of voltage swing?


----------



## amphead

The best answer to that I think, is that the Bijou can drive phones with more authority. So higher impedance phones would benefit with the Bijou.


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Austin is a scary place - with runeight and luvdunhill (maxing out KGSS and revamping the Blue Hawaii), I am not sure my wallet can stand the pressure._

 

LOL. Have you been here during SxSW? It's even scarier then. 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_So, in general, in what ways is the Bijou better than the MillettMax - is it simply a function of voltage swing?_

 

I don't have a MM so I can't judge from sound quality, but there are major differences in the amps.

 The MM is a hybrid that uses low voltage tubes. It will combine the sound of the tube and the sand buffer to some degree. It is also my opinion (and just that) that tubes really sound better at higher voltage.

 The Bijou amp is entirely tubes (except for the PS regulator). It doesn't even use a SS CCS on the plate of the input stage. So you will get more of a "pure" tube sound from it.

 Which one is preferable is entirely a personal choice.

 Both amps have large output electrolytics. This will effect both about the same.

 The Bijou can swing more voltage than the MM (which is limited by the 24V PS to at most 12V peaks). However, the MM sand buffer can push more current than the Bijou (which is limited to about 40mA peaks with the 6N6P output tubes). Your balanced Bijou will double this.

 The only real way you can tell is to compare them. Perhaps Amphead will do that for us when his Bijou finally gets off the operating table. 
	

	
	
		
		

		
		
	


	




 Is there anyone else who has both of these amps?


----------



## rhester

I have both (and have built various versions of the MH Max). I think the main difference is the pure force and emotion that the Bijou can put out that the MH Max just can't. I have the MOSFET version right now of the MH Max and I think it has provided better highs, but the presence and gloriously sensual midrange of the Bijou is hard to beat (especially if you like the tube sound, as I do). There also seems to be deeper, better defined bass with the Bijou ( the MOSFET Max has the ES caps so there is plenty of boom, but it is a little wooly). And these extnesions may be the product of a "blacker, more silet" background with the Bijou.

 Only problem is my casing abilities. Maxes are pretty easy to make attractive, but the Bijou on its plain jane Hammond box is ugly, especially if the cage is on it. I am working on a wood enclosure, which I hope works out a little bit better than some others on the forum.


----------



## rhester

Meant to imply above that the MOSFET has better highs and presence than the other Maxs I have built, but it is still bettered there by the Bijou. There again, there is just a little tinginess on the high end on the Max that the Bijou seems to be without.


----------



## runeight

rhester, thanks for the info.

 i agree with you about the casing. there was an omission in the final bijou production boards. the amp board can be stuffed with components on the underside so the tubes can stick up through the chassis. The PS board was supposed to do this too, but this feature didn't make into production (my fault).

 So, one option where all of the tubes protrude through the top of the box is harder to do because you have to air wire the PS tube socket.

 My apologies for this. If we do another Bijou run I'll fix it.


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_You might get away with a single transformer if you can find at least 150mA on the HV secondary and about 6.3V/6A for the heaters (or two separate 2.5-3A windings). I haven't looked, but there could be a Hammond or RCore that fits these specs._

 


Will the 270HX work, or is the 275v too high? Space is my primary design consideration, well and saving $20 on trannies.


----------



## runeight

yes, that would work. we may need to increase the values of R7 and R8 to provide a bit more voltage drop in the filter section. This should be fairly easy.

 You will also need to leave out the heater biasing components on one of the PS boards since all of the heaters are in parallel and need only one bias circuit.


----------



## funch

Hey, c'mon guys, I like my caged Hammond case! It has that vintage look. It's all black with an FPE panel (the 'Blue Bijou'). The panel really sets off the case. Of course, I'm vintage, so I'm a little biased. Anyway, I just fired it back up after installing the choke in the power supply. Still sounding amazing. It seems to sound a tad tighter, but, hey, what do I know.
	

	
	
		
		

		
			





 Anyway, so far I've installed an extra heater tranny, socketed R2, installed 6H30 input tubes and Auricap 1uF/600v cap's on the output bypass. I'll try to put up some updated pix in a couple of days.


----------



## Ferrari

Funch, are you using the recommended Hammond type choke? 
 And… was it implemented according to variation 1 or variation 2 ?


----------



## tomb

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_<snip>The Bijou can swing more voltage than the MM (which is limited by the 24V PS to at most 12V peaks). However, the MM sand buffer can push more current than the Bijou (which is limited to about 40mA peaks with the 6N6P output tubes).</snip>_

 

FYI - we push the Millett MAX to 27VDC for a 13.5V swing for peaks. This is no different, really, than the older revMH Millett Hybrid when powered by a TREAD or STEPS. It's pretty easy to get that extra voltage when starting with a 24VAC source prior to rectification and cap smoothing.

 All that said, it does nothing to detract from the essence of your statement, Runeight - which is correct.
	

	
	
		
		

		
		
	


	




 The MAX and the Millett were never intended to compete with high-voltage tubes.


----------



## regal

What kind of current do the ECC99 drive in the bijou?


----------



## runeight

Well, to be a bit more precise, at 250V B+ the ECC99 should idle about 20mA giving them about a 40mA capacity. The 6N6P seem to idle about 5mA higher giving them about 50mA swings depending on exactly where each tube is operating.

 I should mention that this is running in class A. The Futterman push pull operation can go AB which will deliver more current. I'll post again about this. Gotta go right now.


----------



## funch

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Funch, are you using the recommended Hammond type choke? 
 And… was it implemented according to variation 1 or variation 2 ?_

 

Yep. The 158L.

 Variation 2, eliminating C5, R7 & R8, and tying the choke into the lead ends of R7/8.

 Here are some updated pix of the changes:


----------



## funch

Check above post, and post #250 for full pix.


----------



## amphead

Good job Funch! Those Auricap bypass caps kick up your layout nicely.

 So, my build is moving along once more. The cutout for the power supply that allows tube/caps to protrude through the top needed a shroud. I'm in the process of putting an aluminum shroud on top of the top plate that covers the PS cutout area. That would get the amp to the wiring stage. The chassis has a simple elegant look. Pics will follow the first fire-up irregardless of whether it is fully noiseless.Edit: one thing that I changed from my wooden enclosure was to mount the transformer 90 degrees from the original position. The iron core faces the direction of the PS board, instead of the bell end. If I remember correctly the lines of electromagnetic flux are strongly emanating from the bell ends on iron core xformers.


----------



## funch

amphead!

 Enough with the teasing already!! We want PICTURES!!!!


----------



## amphead

Wish I could, but for now I'm cameraless. The one that I used earlier died. An associate has yet to drop off his camera, but says he will. Thanks for the enthusiasm! 

 The shroud has been mounted over the power supply and so the amp is officially in the wiring phase. Its taking longer to get it done than the pyramids at Giza.


----------



## regal

installed a cheap used pair of Amperex 6DJ8 haloed getters today. I wasn't expecting much as they were only $20.
 The improvement over the Sovteks brought tears to my eyes.


 Planning on biasing the 6DJ8's to 5mA's today. My calculation is that the 6DJ8's at 5 mA's + ECC99 will use the same power as the stock bias +6N6P. So I think the power supply can handle the extra bias as long as using the EZ81.


----------



## GeWa

Dam'n, I just realize that I ordered the wrong choke! 
	

	
	
		
		

		
		
	


	



 I have an 158M instead of the 158L, oh well....

 Regards


----------



## Ferrari

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_Dam'n, I just realize that I ordered the wrong choke! 
	

	
	
		
		

		
		
	


	



 I have an 158M instead of the 158L, oh well....

 Regards_

 

Don't worry my Belgian friend! I think that you can use the Hammond 158M filter choke unless it's only 10H instead of 15H of the 158L. Comparing to the 158L, it has lower serial resistance (262Ω instead of 411Ω of the 158L). It would be fine if you use PS variation 1, increase the vavue of R7 to 390Ω. (C4 and C5 can be changed to 68µF but 47µF at these posision will also OK).


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_yes, that would work. we may need to increase the values of R7 and R8 to provide a bit more voltage drop in the filter section. This should be fairly easy.

 You will also need to leave out the heater biasing components on one of the PS boards since all of the heaters are in parallel and need only one bias circuit._

 

Can we revisit this for the 270HX  and resistor values? Since I am also the DIY lowest common denominator, can someone explicitly tell me what the heater biasing components are?

 Anyone worked up a balanced wiring diagram? This can wait for weeks yet...

 Finally, I am taken enough with caps to look at alternatives for coupling caps (C6), and love the Auricap implementation - also looked at some Wima Black Box, but do wonder about other price / performance options, skewed a bit more to the performance side.


----------



## bhjazz

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Finally, I am taken enough with caps to look at alternatives for coupling caps (C6), and love the Auricap implementation - also looked at some Wima Black Box, but do wonder about other price / performance options, skewed a bit more to the performance side._

 

Then what you need is this!


----------



## pabbi1

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Then what you need is this!_

 

I know, I know, I know... BUTT - for whatever reason, I cannot resolve to Dvsatik's site - not that I am asking for clues about that, as we have emailed privately... more like the alternative experiences within the Bijou specific, and with Senns under micro focus. Looking at a deal on some Jensens, or Russian PIO / polypro, most likely Kimber / Auricap / Sonicap... unless some copper / silver foil pop into play...


----------



## bhjazz

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_... more like the alternative experiences within the Bijou specific, and with Senns under micro focus. Looking at a deal on some Jensens, or Russian PIO / polypro, most likely Kimber / Auricap / Sonicap... unless some copper / silver foil pop into play... 
	

	
	
		
		

		
		
	


	


_

 

Ok. No worries. Just wanted to point you in that direction if you had not seen it before. It makes for good reference reading for me. I think one does need to have a good idea about the circuit first before delving too far into that realm. Still, applying his notes to the bijou might get you thinkin about a particular type. Let me know if you'd like me to copy the most recent version of the spreadsheet and drop you a pm. Happy to help. 
	

	
	
		
		

		
		
	


	




 Also, to complicate things further ('tis my job) I've read a few articles recently on using bypass caps. The ideas in the Alien dac thread made me do it! Seems lots of designers use that as well. Might be a way to tweak a particular sound even more.


----------



## Ferrari

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_...
 Finally, I am taken enough with caps to look at alternatives for coupling caps (C6), and love the Auricap implementation - also looked at some Wima Black Box, but do wonder about other price / performance options, skewed a bit more to the performance side._

 

*C6* on the Bijou amp is not a coupling caps. This task (DC blocking) is for ~99.8% done by C5: the electrolytic output/coupling cap. *C6* bypass C5 (the real output/coupling cap) and is intended to lower the ESR of the electrolytic a bit.


----------



## amphead

Borrowed a camera, to get those pics posted. The amp doesn't have the right channel volume pot mounted yet, and the aluminum top/front plate aren't polished yet.


----------



## fordgtlover

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I know, I know, I know... BUTT - for whatever reason, I cannot resolve to Dvsatik's site - not that I am asking for clues about that, as we have emailed privately... more like the alternative experiences within the Bijou specific, and with Senns under micro focus. Looking at a deal on some Jensens, or Russian PIO / polypro, most likely Kimber / Auricap / Sonicap... unless some copper / silver foil pop into play... 
	

	
	
		
		

		
		
	


	


_

 

I currently have C6 cap bypassed by a .22uf K75 Russian cap. I have a 1uf K42 here to try, and a range of K40 and K72 caps in transit. I look forward to rolling them through. It all sounds good.

 I am really enjoying the Bijou sound as it is, so cap rolling is not a priority at the moment. 

 Special thanks goes to a fellow head-fier who kindly offered me one of his spare 6N6P for a very reasonable price after one of mine expired recently.


----------



## regal

Amphead that is stunning.


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## JamesL

That looks really nice amphead. The bronze/copper feet is a nice touch =D


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## GeWa

*Ferrari*
  Quote:


 Comparing to the 158L, it has lower serial resistance (262Ω instead of 411Ω of the 158L). It would be fine if you use PS variation 1, increase the value of R7 to 390Ω. (C4 and C5 can be changed to 68µF but 47µF at these position will also OK). 
 

Thanks for the explanation. Just did a small check regarding the resistance of the choke. Serial resistance is stated as 262Ω, however on the box it says 195Ω and if I measure it I have a reading of 189Ω. Do I need to increase the value of R7 to 470Ω than? (158L=411Ω + R7=240Ω total=651Ω and 158M=189Ω + R7=470Ω total=659Ω)

 Regards


----------



## Ferrari

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_*Ferrari*


 Thanks for the explanation. Just did a small check regarding the resistance of the choke. Serial resistance is stated as 262Ω, however on the box it says 195Ω and if I measure it I have a reading of 189Ω. Do I need to increase the value of R7 to 470Ω than? (158L=411Ω + R7=240Ω total=651Ω and 158M=189Ω + R7=470Ω total=659Ω)

 Regards_

 

Product change without notification in electronics parts manufacturing is possible. Serial resistance can be changed by using a different type of copper wire, for example. The different between the measured value 189Ω and the value on the box 195Ω is caused by the tolerances of your DDM and the choke serial resistance. Don't worry much about it!

 You are right about increasing the resistor value to 470Ω (the original PS design (R7 = R8 = 330Ω) => 2x 330Ω = 660Ω). This is necessary to provide a bit voltage drop in the filter section right behind the rectifier tube. Be sure to use power resistor at this position.


----------



## GeWa

Quote:


 Be sure to use power resistor at this position. 
 

Yep, 3W as the originals. Thanks.

 Regards


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## dBel84

@amphead - that is looking fantastic, your hard work has definately paid off ..dB


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## runeight

wow amphead, I go away for a while and looks what's here when I get back. Really nice work.

 When do you fire it up?


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## jamess71

Looks great amphead. giving me inspiration to get started on mine. Just need more time.......So much to do so little time


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## amphead

Thanks guys, its all show and no go until I get it wired up. I have to widen the tube holes one more notch from 3/4 to 7/8 inches. The step drill bogged down, so with 3/4" holes, the top plate actually touches the glass on the tubes. I'll work on that today and then I can start wiring the xformer to iec and PS board. Edit: My drill press is a small craftsman and the step drill at 7/8" causes the belt to lose traction. So I switched to my powerful hand drill, and after fighting to make the holes larger for one hour, they are now the right size. Wiring phase begins tonight.


----------



## regal

Has anyone else compared the Russian tubes (from JRussels kit) to the JJ ECC99's ? I think the Ruskes may be smoother on the treble band? Hard to say for sure?


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## bhjazz

Amphead - beauty! Original ideas all around. It look seriously pro. Good job! Thanks for the pics!


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## amphead

Thanks again! Wired up the transformer to the iec and started soldering the output cap C5 and also C2 in a horizontal position, to fit in the 1 and 3/4 inch tall chassis. I'll finish that tomorrow and then wire secondaries from xformer.


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## TimmyMac

According to Alien DAC build instructions, you can jumper the output caps and enjoy the benefits of less signal path caps if your amp has DC protection... would the Bijou qualify? I have a pair of 4.7uf paper/oil caps I was planning on using for output caps but I could just find a place for them in my Bijou build - maybe at C6... thoughts?


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## Clutz

Yes, the Bijou has DC output protection. I would still use the output caps in the AlienDAC though - what if you use a different amp that doesn't have DC output protection and forget that the AlienDAC is outputting DC? Bye bye headphones.


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## MoodySteve

I have an Alien inside of a CK²III amp (which does have DC offset protection) and I noticed a significant reduction in noise when I installed the output caps. I would recommend installing them as well.


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## runeight

Can't speak for the DAC and output caps, but TimmyMac you can use these for C6 so long at they are rated at 250V or higher.


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## cetoole

Quote:


  Originally Posted by *Clutz* /img/forum/go_quote.gif 
_Yes, the Bijou has DC output protection. I would still use the output caps in the AlienDAC though - what if you use a different amp that doesn't have DC output protection and forget that the AlienDAC is outputting DC? Bye bye headphones._

 

Output coupling caps != input coupling caps. I would tend to think that 2.5v, or whatever the Alien DAC's offset is, directly on the grid of the input tube, would mess up the bias just a bit. Then there is, of course, the fun stuff it will do with the pot.


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## runeight

Did not know that the Alien Dac had this much DC before cap. Thanks cetoole. 

 You will mess up the amp if you put any significant DC at its input. This will be true for most amps that don't have blocking capacitors at their inputs.


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## TimmyMac

Quote:


  Originally Posted by *cetoole* /img/forum/go_quote.gif 
_Output coupling caps != input coupling caps. I would tend to think that 2.5v, or whatever the Alien DAC's offset is, directly on the grid of the input tube, would mess up the bias just a bit. Then there is, of course, the fun stuff it will do with the pot._

 

Alright, I've just put them in my Alien at the outputs. It looks ridiculous... these caps are as big as the rest of the enclosure!


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## regal

I don't see any input coupling caps on the Bijou.


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## runeight

Nope. There aren't any. 
	

	
	
		
		

		
			





 So any DC at the input will skew the bias of the first triode.


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## fordgtlover

Just to offer some feeback on output bypass caps. Today, I bypassed the standard output bypass caps supplied with Jeff's kit (Xicon poly), with 0.1uf K40 PIO, and 0.01uf FT-1 Teflon caps. It seems to have opened the high end right up. 

 I picked up some K40 1uf caps as well. I'll replace the current poly caps on the weekend and see how they go.

 These Russian caps continue to impress me. 

 This amp just keeps getting better


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## regal

Where did you find K40 1uF? I resorted to K42's.


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## miky

Quote:


 Where did you find K40 1uF? 
 

RARE!!! 1.0uF 200V PIO Capacitors K40Y-9. Lot of 8 - eBay (item 350069593707 end time Jun-18-08 12:43:10 PDT)


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## I-Love-Music

I don't see any input coupling caps on the Bijou.


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## Ferrari

Quote:


  Originally Posted by *I-Love-Music* /img/forum/go_quote.gif 
_I don't see any input coupling caps on the Bijou._

 

HINT.


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## fordgtlover

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Where did you find K40 1uF? I resorted to K42's._

 

 Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_RARE!!! 1.0uF 200V PIO Capacitors K40Y-9. Lot of 8 - eBay (item 350069593707 end time Jun-18-08 12:43:10 PDT)_

 

I too picked up some K42, which I am yet to try, before I found the K40. The combination that I think will be interesting to try is the K42 bypassed with the K40 (and/or) the FT-1 teflon. The K42 seem to be criticised for lacking in various areas, but personally I don't mind them. May just be my inability to discerne the better quality caps though?

 Miky is spot on. I bought them from that seller. They arrived reasonably quickly too.

 They're physically quite large, but I'll mount them all offboard anyway.


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## pabbi1

What is the typical turn around on boards? 

 I understood I'd get an email regarding shipping, but it has been well over a week... emailed Jeff, with no response - is this normal for GJA?


----------



## dBel84

I am not sure there is such a thing for GJA, Jeff does this to support our hobby mostly and turn around is very much dependant on his free time. Mostly he gets things out quickly but I know that he has been very busy lately. You could always drop him an e-mail but I am sure that you have not been forgotten. BUT I do hope you get it all soon because I am very curious about a balanced Bijou. 

 Just out of curiosity, have you considered using a transformer to convert the balanced signal instead of a separate amp board. I know some consider this sacrilege. I have been toying with testing such an idea but will see about it when I have some time on hand ..dB


----------



## pabbi1

Yes, I sent Jeff an email yesterday - but with the site being down yesterday, it seemed worth checking around a little.
 ... 
	

	
	
		
		

		
		
	


	




 Make no mistake, I do appreciate that Jeff does this as a labor of love (especially for the prices he charges), 

 No real consideration nor ability to alter the circuit in any way - but wanted to follow the successful balance path I took with the MillettMax. At least I know how to wire that one, and retain 2 Single Ended amps also, using Neutrik combo XLR. That way, each channel can be tested with my throw away headphones before risking any of the balanced ones (HD6x0).

 Just being impetuous - it just did not seem prudent to do the remaining casework without boards in hand, just to verify those drill templates.


----------



## amphead

Pabbi, if you don't get a message from Jeff within about 48 hours, feel free to fire off a PM to Runeight. If worse comes to worse, I would have to etch you a set of boards, so don't worry. 

 I'm in the middle of wiring up heaters on my build. Should be testing within 24 hours. Yes you can hold my feet to the fire. But no torches and pitchforks.


----------



## Clutz

pabbi, sometimes I have found Jeff gets busy and takes a while to respond. I've ordered from Jeff several times, and sometimes he has been super prompt to reply (e.g. several responses in a single day!), and other times he hasn't replied for quite a while. Like dbel said, he's doing this on the side and sometimes he gets otherwise preoccupied with life, but I give Jeff two big thumbs up.


----------



## I-Love-Music

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_HINT. 
	

	
	
		
		

		
		
	


	


_

 






 Thanks, dude. Seems I do have a lot to learn.


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## regal

I completed the 5mA 6922 bias mod to my Bijou.

 Here are the changes:

 EZ81 tube
 JJ ECC99's for V2
 R2 - 487 ohm (1/4W)
 R3 - 30K ohm (2W)
 R5,R6,R7 - 10K ohm (1W)


 You can only use the ECC99+EZ81 combo with this mod, I think the 6N6P's use too much current. The EZ80 probably doesn't have enough power.

 I came up with this mod based on the fact that the 6N6P's use close to 10 mA more current than the ECC99's. This gave the extra power available for the 6922's which were running 1.5 mA's. 

 There is a noticeable improvement in the bass, it sounds cleaner to me. There is an improvement in the upper mids as well. I put my DV337 in the closet. I think the original bias point is fine and was chosen to meet the power supply at the time, now that we have the better transformer, rectifier, and heatsink we can get a little more out of the amp.


 I want to make a plug for Fluke. When measuring the B+ I mistakenly had the meter set to resistance. Didn't phase it one bit, mofset still good too. I have made this mistake measuring HV with cheap meters before and blown up not only the meter but components as well.


----------



## runeight

regal, this is no doubt a good mod to the amp. thanks for making it happen.

 you might still be able to use the 6n6p with the ez81. have you measured the voltage at the input to regulator? there could be just enough headroom there to draw10mA more.

 pabbi1 i've been meaning to add a bit more information on the balanced version, but I had forgotten. earlier i posted that the current delivery capability should double in a balanced version. normally this would happen because the peak voltage across the load is doubled. but i had forgotten that the peak current from the bijou is determined by when the O/P tubes go to positive grid. this was part of the original design, that is, to run the O/P tubes to where they could reach positive grid so that this would be the only limitation on the O/P stage. what this means is that the peak drive current from a balanced amp won't be much more than a single amp. just wanted to tell you this before Jeff actually sends you all six of your boards.


----------



## pabbi1

No problem - almost all the parts have been procured for the balanced version - so, I am still building two amps in the same case... 

 Anyone know the mounting screw size on the boards? 6 (i.e. 6-32) or 4 (4-40)?


----------



## amphead

I like to use the more robust 6-32 for physical stability, and come to think of it I may have used a needle file to slightly open the holes for 8-32. This prevents my boards from moving and I'm using nylon lock nuts.

 Just finished mounting my RCA input jacks. I chose to mount them on the right hand side of the chassis, to shorten the signal path a little. Better get back to work, or I'll miss my 24 hour deadline. Then Alex will make me walk across the hot coals.


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## TimmyMac

6-32 is the biggest that fits. I've used 6-32 for the power supply and 4-40 for the amp boards, but only because when I was buying hardware I somehow got it into my head that the amp boards had smaller mounting holes.


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## pabbi1

Casework done and the outside- just waiting for, er, boards... 
	

	
	
		
		

		
		
	


	




 Save for mounting the attenuators and Neutrik combo jacks, and drilling / finishing the (curly mahogany) wood plate, case is done, with about 6 hours total.


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## amphead

Looks good Pabbi!

 I have just about finished wiring, but will do that tomorrow. Then.......


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## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Casework done and the outside- just waiting for, er, boards... 
	

	
	
		
		

		
			





 Save for mounting the attenuators and Neutrik combo jacks, and drilling / finishing the (curly mahogany) wood plate, case is done, with about 6 hours total._

 

really, really nice pabbi1. have you not yet heard anything from Jeff R??


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## pabbi1

Sorry, posted in the other thread - boards shipped yesterday. he ships on weekends, and just missed my order last weekend. Good to go, as parts are mostly in place, and the balance should be here this week.


----------



## amphead

Test complete on the re-cased/aluminum chassis. There is a small buzz from 1/2 to 7/8 turn of the volume pot that increases with volume. With the volume pot increased to maximum the buzz drops out. Listening to the amp with volume at maximum and the source turned down sounds beautiful. In my mind, this points to the power source, because an amplifier board would effect one channel usually.


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## runeight

$*#&@)&#@(@ I really don't believe this is happening (I do of course).

 The behavior does not necessarily point to the B+. Noise on the B+ would go right into the plates of the input stage and phase splitter. The noise wouldn't change with the volume pot. At least I don't see how it would.

 Have you tried isolating the grounds of the source device and the Bijou?


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## amphead

The Bijou is grounded at the iec earth ground/star ground point. My Walkman mp3 player, is the source device. I have also used a cd player as my source device with the same results. Damned confusing aint it? My feeling, is that if I shipped you my PS and you plugged it in to your amp, it would give you a buzz.


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## runeight

Hmmm. Do you have access to a scope? Have we been through this before?


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## amphead

Yeah, a scope at my brother-in-laws. I have to hurry, he's an engineer/vp at an elevator controls company and leaving for Spain to do a convention display.


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## runeight

If you can get the scope, it will be worth a look at the B+. Since the grounds are now solid to a conducting chassis, there are not too many other things that can cause this problem.

 What happens if you put a 100R resistor across each input to ground (without the source) and then rotate the volume. Do you get the same effect?


----------



## amphead

Alex, I didn't make it over in time to get to his scope. He's early to bed and early to rise. I'm still up into the wee hours usually. I've been giving a burn-in to this set-up to see what it's made of. So far it's been running steady for 3 hours. Transformer gets quite warm, but I can hold my hand on it for quite a while, same with top plate and shroud. I'll try shorting the input later tonight with those 100 ohm resistors. Thanks for your help.


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## amphead

Shorted inputs with 500 ohm resistors, since thats what I had. Identical buzzing sound that increases with volume. Then with the volume pot at maximum travel it goes quiet. If I play some tunes with the buzz, its covered up by the music to give you an idea of the level we are talking about.


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## runeight

amphead you must be more than exasperated. And I am not able to discern what the problem could be, but let's step through this.

 With 500R shorting the input and the vol pot set to zero you get buzz. Correct?

 Then buzz increases with volume until you get no buzz at full volume? Does the buzz disappear instantly or over some amount of travel in the pot?

 What happens if you just short the grids of the input tubes to ground with a very short wire? Do you still get buzz? Have we tried this already? 
	

	
	
		
		

		
		
	


	




 Obviously, this last condition is what happens with the vol pot set to zero, but I am grasping at the moment.

 But, in any case, let's try to see what this means one step at a time:

 1. If the noise were coming through the input signal wires, then full volume would give the loudest buzz. Not happening.

 2. Source is not line grounded, so no ground loop. Besides, we ran the test with no source connected.

 3. Both channels have the same problem and behave the same way.

 4. If buzz was coming from the B+ then it should be independent of the vol pot and just buzz all of the time. Not happening.

 5. The two logical conclusions are still that there is:
 a. A ground problem
 b. Buzz is being introduced in more than one place and is being cancelled when the vol pot is at full rotation.

 Try this. Pull out both input tubes. The input and output stages are totally capacitatively coupled so the O/P stage will bias up no problem with the input stage gone. Nothing should be damaged by doing this. 

 Do the output stages buzz all by themselves?

 Also, I know that you've done this already, but could you please check again the grounding on the PS board.


----------



## amphead

Ohmed out good from PS board ground connection to star ground. Then I pulled the input tubes, then powered up with phones on and Walkman running,.........zip, nada, nothing dead silence for all positions of the volume pot.


----------



## runeight

Well, #*%$+, this is at least progress!!! We know something that we didn't know before.

 Now, the PSRR of the output stage is about 10db better than the phase splitter, which has, basically no PSRR. Still, if the buzz is significant on the B+, you could probably hear something in the headphones when the input tubes are out. It is possible that the noise is right at the level where it is audible through the splitter but not through the O/P stage. But I kind of doubt it. We should remember to get back to this though if we get seriously stuck again.

 Note that with the splitter triode out of the circuit, the plate resistor floats right to the B+. If B+ noise were getting into the splitter, it would go directly into the upper coupling cap. This appears not to be happening 'cause the O/P stage is quiet.

 So, my guess is that the B+ is clean and not the source of the noise. Does this make sense? Tell me if my logic is wrong, because this will dicate the next steps.

 This also means that if the problem is EM radiation it is not getting into the coupling caps or the O/P tubes or the phase splitter's resistor chain. However, there is no gain from the coupling caps forward. The phase splitter has no gain either. It still could be that the buzz is just below audible at the B+.

 This puts the problem at the input stage. The PSRR of the input stage is over 30db with these component values (about a factor of 30x). Any B+ noise will show up at the grid of the phase splitter 30x lower than it appears on the B+. Since the splitter has no gain, the buzz would not be amplified beyond this point. If this logic is correct, then if there is B+ noise and it's not getting through the phase splitter's plate resistor to the coupling cap (when the input tubes are out), then why would a 30db smaller signal that is not further amplified get through its grid to the coupling cap and be audible?

 OTOH, the fact that the buzz stops when the vol pot is maxed indicates a possible cancellation issue.

 So, what to do? This is a hard problem to track down. One thing to try very, very, very carefully. Insert one input tube back. Put a 22u cap from the input stage plate to ground. Try the vol pot. Does the noise go away?


----------



## amphead

Looking for a HVoltage 22uF cap in my parts bin. I'll give it a try after dinner, and post back here in about 3 hours. Edit: found a massive 630v 22uF Solen film cap. 
 Edit: need more time to try the 22uF cap. Can't say when I'll have it in just yet.


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## amphead

Pin 6, is the plate for triode 1 therefore is the input stage plate. I am in the process of soldering a lead from pin 6 to one end of this monster cap and the other end of the cap gets a lead to the ground point at the board connector star ground. Here goes......


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## amphead

With cap across plate to ground, there is a buzz that increases with the volume pot. And as before the buzz goes away at full travel of the pot.


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## pabbi1

You are living my Bijou build nightmare.


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## amphead

Pabbi, the problem that I am experiencing is probably going to end up being a bad component on a board. Most builders have not reported having this buzzing sound. In fact, Rhester reported the Bijou as having a very black background resulting in extended bass. I certainly am not lacking in the bass department. K701s are not particularly known as bass monsters, but they do well in that department with the Bijou. Once I find the problem, with Runeights help, all will be revealed.  Edit: troubleshooting pics of the boards/interior coming soon, probably tonight.


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## runeight

my nightnmare too folks. amphead i'm going to check with someone who is a much better tube guru than I am because I don't have any more useful suggestions. Please give me a day or so to exchange the emails.

 It is true, pabbi1, no one other builder has had this difficulty. amphead just has something in the build that isn't quite right. and we haven't found it yet.


----------



## amphead

Ok, sounds good. In my earlier career as a semiconductor manufacturing equipment technician for Intel Corp., we had the luxury of isolating a problem block, by swapping a board for a known good one. If necessary, I'll just order a set of boards and populate with new resistors/diodes and try to get the other type of voltage regulators/mosfets, partly out of superstition, and put my caps on the new boards. Caps would get swapped out if the buzz hasn't gone.


----------



## TimmyMac

Anyone know why my B+ won't come above 237V? While testing with a 100k resistor across B+ it was fine, and I could adjust to 250V no problem. Once I attached the amp boards it wouldn't do more than 237 with the trimpot maxed out. I can make it go lower, but not higher. Blown EZ80?


----------



## runeight

the ez80 is probably ok. are you using 6n6p output tubes? What we've noticed in the builds is that these are pulling much more current than was anticipated and this is pulling down the input voltage to the regulator.

 Does the amp work otherwise? It can run very happily at 237V. So if it's working and nothing is smoking, go ahead and use it.

 You can take one simple measurement to verify what's happening. If you measure the voltage at the lead of R7 where it sticks up from the PS board, what does it say? if it's down around 255V or even less then there is one simple solution - use an EZ81 for the rectifier. If you have the Hammond 270DAX transformer, it will handle this.

 I have recommended to JRossel that any Bijou kit that goes out with 6N6Ps should also go out with EZ81s for the rectifiers.

 My apologies for this. During the proto build process we tested the 6N6Ps and we did not, IIRC, encounter this problem.


----------



## TimmyMac

If the amp is happy at 237V, then so am I. The EZ80 is very hot too - is this because it's maxed out? I may put an EZ81 on order.

 Sound is great, I just plugged in my phones. Funny thing though - when I touch the NFB pot (no knob on it yet) I get a buzz similar to what you get when you touch the middle pole of an RCA cord that's plugged into an amp. Should I ground it with a wire? There's also a faint background noise when I turn the NFB pot all the way down, and a slight buzz if I move my hands hear the internals. Any idea about these? Just induced noise? I have my tube sockets air-wired and all the heater wiring is air-wired as well, if this would make a difference. 100% dead silent with the NFB turned up. I'm using sony SA5000 headphones (70ohm) if that makes a difference.

 edit: Voltage at R7 is 243V


----------



## runeight

yes, the ez80 is hot because it's running close to max and sweating pretty hard. Voltage at R7 says that your 6N6Ps are sucking lots of current. An EZ81 should fix this.

 You'll need to ground the NFB pot get rid of that touching buzz. Connect directly to the star point. Even after you attach a knob, it would be better to ground this pot and the vol pot.

 Is the amp cased up? If not, internal wiring will pick up EM from almost everywhere. And your body is a great antenna so when you wave your hand around you are injecting signal too. 
	

	
	
		
		

		
		
	


	




 Have you used shielded wire for the input jacks to pot and pot to amp boards? And from amp boards to NFB pot?

 The best way to solve the EM problems will be to have a good enclosure that is well grounded.


----------



## TimmyMac

It's semi-cased. I built the case from a wood frame + top and bottom steel plates. The only shielded wire is from the EZ80 heater pads on the PS board up to the EZ80 socket. The heaters for the other tubes are wired from pin 4/5 on the EZ80 socket. If I can find a camera I'll post a picture. Thanks for the advice though - should I line the wood frame with foil or something along those lines?


----------



## runeight

If you still get the slight noise after grounding the pots and replacing the EZ80, then the next step would be the shielded wire that I mentioned previously.

 Only if you still have the noise after that should we worry about lining the enclosure.

 Oh, let us know how you like the sound of it after you've had some listening time.


----------



## TimmyMac

It seems to disappear when I disconnect the source - a USB-powered Alien DAC. iPod as source doesn't make the noise. Ground loop? USB bus noise? My other amp (Millett hybrid) doesn't make the noise with this source. A slight 60hz hum remains but I'm sure that's because my heater wiring is unshielded and close to the signal at one point. Grounding the NFB pot fixed that problem, although it was not easy getting enough heat onto the body of the pot to solder it


----------



## runeight

Could be either, but let's assume it's ground noise from a loop. Are your input jacks isolated from the chassis? This is an aside question, I was just curious.

 A ground loop breaker would be the easiest to execute. There are many posted around the web.


 But I am delighted to know that we don't have an internal buzz problem. Amphead's buzz is driving me crazy (and who knows what's happening to him 
	

	
	
		
		

		
		
	


	




 )

 Hum is most likely from long, exposed heater wires in proximity to signals. If you haven't shielded it, I assume that you have, at least, twisted the wire pair tightly together.


----------



## TimmyMac

Input RCA jacks are isolated. Here's a couple photos so you can see what I'm talking about.








 I guess I'll work out a ground loop breaker and see what that does.


----------



## runeight

Thanks. These are really helpful.

 One problem is the very long input pair from the jacks to the vol pot. These will pick up the most noise. Shielding them will be a big help. And the NFB pot wiring.

 For the heaters, it would be better to run them straight down to the metal, then along the metal, and then straight up to the socket. Then keep any signal wiring perpendicular to the heater wiring wherever they cross.

 My guess is that doing these things will make the hum go away. And the ground loop breaker will handle the buzz from the source.


----------



## TimmyMac

The idea was to keep all the heater wiring flush with the top panel, so the panel (which is grounded via the EZ80 socket holder) could absorb some EM and so it would be far from any signal wiring at the bottom panel level - where the boards are and such. If this is flawed I can change it up.


 Anyways, I found the source of the hum... One of the wires to the left channel 6N6P broke off the tube socket. Now it's quiet except for the source noise. Why does this go away when I turn up the NFB?


----------



## runeight

Oh. I see what you're doing. That should work ok if the top cover is well grounded. So now it's just a matter of using shielded cable on the important signal runs.


----------



## amphead

You just reminded me of what I forgot to do on this build. I have the input wires tightly twisted going to the pot, but they aren't shielded. I suspect EMF interference is causing my problem, because I took the amp over to the university to get some pics, and the massive bank of flourescent lamps increased the buzz by about 5 times.  Shielding those is my next step, as well as my unshielded output jack wires. Edit: I'm also going to rework the star ground, because it consists of six wires soldered to a single union which is bolted to the inside base. This is anodized aluminum which was scraped a bit at the point where the star ground is. I am going to make a buss plate, by hacksawing a short piece of copper pipe and unfolding it to a flat plane.


----------



## runeight

I see. I thought that the inputs were shielded. Let's see what happens when you shield the signal runs. You may not have to modify the ground.


----------



## TimmyMac

I can get decent results if I plug the interconnects so that only the centre pin contacts and the ground ring doesn't, or if I just turn the NFB all the way up... this is definitely looking like a ground loop.


----------



## amphead

My rig........


----------



## amphead

Inside view........


----------



## amphead

PS board view........


----------



## amphead

Star ground before the copper plate modification upper right.......


----------



## amphead

Amp board.........


----------



## TimmyMac

Those pictures make me wish I'd built my case bigger - the wiring looks so clean! 7.5x10.5 interior is a little tight in some places.


----------



## funch

runeight;4351361 said:
			
		

> the ez80 is probably ok. are you using 6n6p output tubes? What we've noticed in the builds is that these are pulling much more current than was anticipated and this is pulling down the input voltage to the regulator.
> 
> FWIW, I'm running the version 2 choke setup on mine with 6N6P's/EZ80/270DAX and I have no problem getting 250V.
> 
> amphead: very nice looking build.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_My rig........_

 

Nice job there, amphead. I especially like the RCAs on the side. An interesting consideration.


----------



## amphead

Thanks again! I'm currently finished installing shielded wire from pot to rca's and pot to amp board inputs. Now I'll install the shielded wire from Neutrik output jack to amp board output connections. Then test.......
 Edit: oops small setback, I'll fix it tomorrow.(Phoenix connector)


----------



## adamus

and..... I am in suspense! leep up the good work amphead, you will crack it.


----------



## regal

Been looking at lineamp designs lately. Here is a Broskie design that would be easy to mod to from a Bijou pcb.

 Not sure I understand what happens after the phase splitter vs the Bijou.


----------



## TimmyMac

Well my build is finished... here it is:


 














 The flash sorta blows out the glow of the tubes, but I don't have a tripod so this is the best I could do. Sound is amazing... as described, very quiet, rich sounding... I haven't put much listening time on it but my Alien DAC just crapped out so I'm stuck with my iPod for now. Case is DIY from 3/4x2.5" mahogany stock and two plates of 1/16"-ish steel - cut at a local welder. Cost $15 + tools.


----------



## TimmyMac

I might add that this amp has done something my system hasn't managed to do before. I find myself losing track of time or what I was reading and spacing out listening to the music. Kudos to runeight (I think) for the design.


----------



## runeight

Thanks TimmyMac. Yes, it is my design and your listening experience seems to be fairly typical. It happens to me too. I often wait until very late when the house is quiet, turn out the lights to watch the tubes, and just listen really hard. It's a very cool amp.

 You did a really nice job on the build too. Way better than my prototype.

 I guess all of your noise problems are solved now?

 regal I have some thoughts for you, but I'll have to post later in the evening.


----------



## Postal_Blue

Timmy that is a beautiful build. Hats off.


----------



## funch

TimmyMac: very nice build. I especially like how you recessed the knobs and 'phone jack.


----------



## dBel84

another kudos to your build - beautifully done..dB


----------



## runeight

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Been looking at lineamp designs lately. Here is a Broskie design that would be easy to mod to from a Bijou pcb.

 Not sure I understand what happens after the phase splitter vs the Bijou.
_

 

The stage after the splitter is a WCF just like the Bijou. Mr. Broskie has, however, with some very clever resistor-ing balanced the output stage by feeding the output back into both the top and bottom triodes. He also doesn't cross the phase splitter outputs like the Bijou does because he doesn't need to.

 This amp should perform fairly well as a line stage, but my guess is that the Aikido will perform better and be quieter. One problem with this design is that there are 50k resistors in series with the grids of the output tubes. This will slow the map down some.

 But, you can see the evolution of John's thought from here to the Aikido.


----------



## bhjazz

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_Well my build is finished... here it is._

 

WOW!

 Very nice work, TM! I especially like the organization of the tubes arranged in a circle. Looks like you didn't use the pcb's at all...did you? 

 Impressive!


----------



## amphead

TimmyMac, I'm blown away by the look you achieved! Thats really beautiful. 

 In my case, something that I've attempted to do has caused me to lose my left channel after the amp is running for about 7 minutes. Replaced the Phoenix connector on the left amp board input and soldered wires directly to the board and ran shielding to ground. Ran shielding to ground for both runs from pot to RCA's. Will be troubleshooting late into the evening. Edit: this is with buzz still happening, so I'm not thinking that the buzz is related to input/output shielding like I was yesterday.


----------



## TimmyMac

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_TimmyMac: very nice build. I especially like how you recessed the knobs and 'phone jack._

 

Yeah, that was a good bit of work with a hole saw and a bench grinder to bring the neutrik jack down to a round shape (took off the bolting flanges and epoxied it into a round hole). Slight recess cut out with a hobby knife for the release button.


----------



## TimmyMac

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_WOW!

 Very nice work, TM! I especially like the organization of the tubes arranged in a circle. Looks like you didn't use the pcb's at all...did you? 

 Impressive!_

 

Yeah it's more or less a bone-stock build from Jeff... I just air-wired the tube sockets up to the top panel of the case. EZ81 will be on order when I get back from my summer job which I'll be off to tomorrow night.


----------



## fordgtlover

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_I might add that this amp has done something my system hasn't managed to do before. I find myself losing track of time or what I was reading and spacing out listening to the music. Kudos to runeight (I think) for the design._

 

Very nice build - congrats.


----------



## TimmyMac

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Thanks TimmyMac. Yes, it is my design and your listening experience seems to be fairly typical. It happens to me too. I often wait until very late when the house is quiet, turn out the lights to watch the tubes, and just listen really hard. It's a very cool amp.

 You did a really nice job on the build too. Way better than my prototype.

 I guess all of your noise problems are solved now?_

 

Yep, noise is completely silent except whatever noise comes from my source. No trace of 60Hz hum, and the other noise was apparently from my DAC about to die. PCM2702 chip died as far as I can tell - the left channel is gone. When I get back in August I'll build an Opus or Jambo DAC or something along those lines, but for now I'm using soundcard or iPod output.


----------



## amphead

Interesting Voodoo on my left channel. I reflowed solder on the board input connections and the triode 1 and 2 on the first tube. System played well for 20 minutes and then some loss of sound in left channel. I pulled the top off the chassis with system running, and using my insulated tweaker I pushed lightly on the input tube and the output cap and heard the sound go intermittent on/off, in the left channel. Tomorrow I'll reflow some more points in the left channel. There's definitely either a cold solder joint or flaky component going on there. I usually don't work live like that, however I think under these circumstances I had no choice, and certainly don't recommend for others to do it.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I usually don't work live like that, however I think under these circumstances I had no choice, and certainly don't recommend for others to do it._

 

Wow. Geez, man, I sure hope you can get to the bottom of this. What a bummer. 
 I had to do some of that with my Bottlehead build. Doc B. recommended using chopsticks to poke around and tap on components when the gear was running. Exhilarating, to say the least...

 Hope you get to the bottom of it soon!


----------



## amphead

The fix to the left channel, ended up being a more thorough reflow once again of everything that might have possibly had a cold solder joint, both tube sockets, output capacitor, output cable connection and the input Phoenix connector. Listened to tunes for 2 hours to verify  Now back to finding the buzz........


----------



## pabbi1

WRT to wiring the Hammond 270HX, it only has the two black leads for input? Either to L and N, or ??? Any grounding?


----------



## runeight

No, no grounding on the input. Connections don't matter.


----------



## amphead

Pabbi were you thinking about the iec connector? The ground for mains is there. 
 Still working........


----------



## pabbi1

Boy, I so hate waiting on caps from Hong Kong... and attenuators from Taiwan... and tubes from Latvia... and sockets from Canada... and rectifier tubes from NY... other than that, I am good to go, after yet another heatsink run to the local surplus place...

 Ok, here is some ****. 



















 I'll start working amp boards tomorrow, as I at least have all the parts for them... and, if anything looks amiss...

 Alex, those are the 10w resistors hanging off the side. I also have some chasis mount 15w 470r, but wasn't sure what wire it would take to wire them up, nor how, so let me know if you think this is risky. Oh, and these are some hybrid heatsinks (2 types thermal pasted, and the pins super glued in, but might have to go to JB Weld, which is rated to 600 degrees F), just in case - I think they will fit with the caps, but will have to wait until they are here to make sure.

 I am still worried about the signal wire bring too close to the amp boards, but maybe shielding tape would alleviate this?

 Overall it is a tight fit. I'll post with amp boards tomorrow.


----------



## regal

Pappi, Is that 2 power supply boards? Will this be a balanced Bijou ?


 I used shieled mic cable for the input, grounding the shield at one end.


----------



## pabbi1

Yes, balanced to work with the Azur 840c. I'll wire the combo jacks for balanced and SE that Ti Kan to generously explains on the b22 site. I have the Millett balanced that way - mainly so I can test the output with cheapie throw aways before plugging in the HD6x0 balanced.


----------



## amphead

Pabbi, you should be good to go with what you are doing, looking real good. These get a bit warm, so think about ventilation, or just add vents where needed.

 In the case of removing buzz from my build, this is something I'm going to try with 100 ohm resistors from xformer heater supplies to star ground. It's supposed to be a work around for not using the heater center tap. This is per my engineer brother-in-law/tube guru.






 Well, maybe not......
  Quote:


 *Runeight* says...amphead, i'm afraid you can't use a humpot. The heater circuit is already biased to about 40V by a voltage divider on the PS. This is there to reduce the HK voltage on the phase splitter and upper output triodes. 
 

Looking at the PS schematic I see R9, R10 and C7.......Is R9 bringing my circuit heater buzz?


----------



## Ferrari

It seems to be a never ending "buzz story" or whatever you want to call it 
	

	
	
		
		

		
		
	


	










. It's very unlikely that the resistor R9 of the power supply bringing buzz in the heater circuit. Many people (me included) have built and using this power supply in the Bijou without any buzzing (or whatever) problem. Have you tried other components (tubes, volumepot, shielded cables...) and sources (CD/SACD/DVD players) ?

 Btw, the 100 Ω resistors from the transformer 6.3V heater supplies to ground is nothing new and is extensively used in heater supplies for tubes amps. (take a look at Headwize, in some amps designed by Andrea Ciuffoli or many other designs at DIYaudio.com).


----------



## dBel84

@ Pabbi It's comming together nicely. Those Nabu cases really are ideal amp chassis. 

 No comment to amphead [head down and shaking?] ..dB


----------



## regal

I think R9 is biasing the heater to keep the Heater to cathode voltages apart, if anything it is there to prevent buzzing from electrons knocking off of the heaters.


----------



## runeight

amphead, your 100R biasing technique will not work and will likely fry R9. R9 and R10 form a voltage divider from the ps to drop the votage before regulator from around 280V to 40V. The 10u does a very good job of filtering noise from the PS, particularly when it is preceded by a 348k resistor.

 If you look carefully you'll see that the R9's path to ground is R10. If you make R10 100R the current flow through R9 will be WAY TOO HIGH. R9 will fry.

 I don't believe that heaters are your problem. If there is any way you can find a scope that might be quite helpful.

 However, if you want to try the heater mod, then remove R9 and use the two 100R resistors to see what happens.


----------



## funch

I ran accross this a while back: Tweaks

 Click on 'tweaks for electronics' and look at #2. 

 Is this valid? Do LED's introduce noise?

 I'm running a yellow LED in each amp board right now. Would it be worth it or even recommended to remove them, along with the RLED and D7?

 Could this be part of amphead's buzz problem?


----------



## runeight

at this point this would be a useful step to take. it could be that the LED, but particularly the diode switching transients, are introducing noise into the amp sections.


----------



## pabbi1

Speaking of rled, my led is 3.8v, and is I = intensity? If so, that is 60, so (9-3.8) / 60 = .09. So, in other words, I have no clue. The wavelength is 428.

 Mine are the blue, first part on the right hand column on this Mouser page.


----------



## runeight

I is the current that is a specified for the LED for normal brightness. Although many builders like to run the LEDs at less current.

 But, let's say that the LED current spec is 10mA. Then your formula is:

 RLED = (9 - 3.8) / 0.01 = 520.

 The closest value would be 560R and this would be good enough.


----------



## holland

LED_calculators

 The number on the mouser page for lumen intensity is the mcd.

 Plug in, figure out what you are trying to reach and you can get what you need.

 FWIW, I use the ultra bright lite-on LEDs and I tend to go for < 1mA, but it's not that big a deal for me. YMMV.


----------



## amphead

Cut the Rled, D7 and Led out of the circuit and........70% reduction in the buzz. Buzz is very small now. So come on people I'm almost there to the finish line.......forever.  Edit: diode D7 snapping at 120HZ, the likely culprit.


----------



## runeight

Damn, this is really good news. Yes, D7 is probably the culprit.

 The proto boards did not have an LED on them. This request was made as part of the prototype process and so I never tested it. And didn't think about the fields from the onboard diode.

 amphead, my sincerest apologies for this oversite.

 But, as you say, you are very close now.


----------



## pabbi1

Is D7 an issue, as I haven't populated mine yet?


----------



## runeight

It's really the LED circuit that is the issue. I would simply recommend that you don't use the LEDs on the board. If you leave out D7 the LED will still create switching transients and might not like the reverse voltage.


----------



## dBel84

I was going to say that the prototype boards never had the led - buggers , well you have faught a worthy cause for all ..dB


----------



## adamus

great news.


----------



## fordgtlover

So, is the suggestion to remove all of RLED, D7 & LED1?


----------



## amphead

Well, bring on the torches and pitchforks. I am going to refute what I said earlier about the buzz being reduced by eliminating the Leds/D7. Keep on using them. Now that I have re-evaluated the sound again at night the buzz is still there approximately the same. Yes I'm making my confession, as I don't want to lead everyone astray. Sometimes you expect a change and your mind plays tricks on you. On to using a scope, to locate the problem. To answer your question Ferrari, yes I have tried putting 6n6p in all 4 positions with same buzz, tried different sources, shielded cable on signal wiring, etc. dB....go back to shaking head. Runeight, run me through the torture device. I apologize for misleading/derailing everyones use of Leds. ;-( That is not causing the problem, and they are a great indication of heater continuity as Alex intended them to be. Edit: I would be very hesitant to second guess the design with the removal of R9 to try the 100R resistor method, because this is not that style of amplifier, and needs to run as it was intended.

 Pabbi, you may not need to add ventilation, because the size of your chassis being large will probably work out very well.

 Ferrari, I am considering the use of a separate 12vdc heater supply. Did you build regulated or unregulated, for your amp? Pics/schematic Please?


----------



## regal

Runelight,

 I am looking at using the Bijou PS to power a Broskie Aikido to use in a linestage of a DAC. How would I know the max current your PS can deliver? I have seen reports that the EZ81 is good to 150 mA, but this doesn't sound right because we aren't close to that with the Bijou.


----------



## runeight

Edit: My previous post was late, after other posts that I did not see. It doesn't make sense now.

 regal, the max current is primarily determined by the mosfet power dissipation and secondarily by the filter caps.

 The pass fet needs at least 10V across it to run properly. The heatsinks, IIRC, is 10C/W. So, you can figure out how hot you're willing to let the fet get and this is the current you can draw.

 Now, more current means less filtering from the caps. At some point this will affect the ripple at the output. But, with the currents you are likely to draw, I don't believe this will be a factor.

 I would say. conservately, you can get 100mA. Use the EZ81 and make sure that the input to regulator voltage is over 260V. You'll need a transformer that can deliver 100mA.


----------



## funch

I just refired my amp after removing the LED's, D7's, and RLED's and the slight hum that was in the left channel is gone. Hasta la bye-bye. Amp is now quiet as death. I would concure that it's worthwhile to remove/leave out those components.


----------



## amphead

Funch, I believe that it has helped you to get yours quiet. I really didn't get any significant improvement, but I think I'm having another problem.

 I found this Ferrari, and looks like what you used for your amp.







 C1114000uF or 10000uf 40 VDC Electrolytic Capacitor
 C21100uF 50Vdc Electrolytic Capacitor
 C310.1uF Disc Capacitor
 C410.01uF Disc Capacitor
 R115K Pot
 R21240 Ohm 1/4 W Resistor
 U11LM338K 1.2 to 30 Volt 5 Amp Regulator
 BR1110 Amp 50 PIV Bridge Rectifier
 T1124 V 5 Amp Transformer
 S11SPST Toggle Switch


----------



## amphead

Procured an LM338K, and I'm looking for a suitable xformer. I found 24vac at 50VA, but without a max current spec. Edit: starting to think 75VA will be the minimum size to handle the current.


----------



## funch

I'm gonna pull an 'amphead' here and ammend my previous post. Now that it's night time and quieter, I can still hear an etreeeeemely faint hum equal in both channels. It's only audible between tracks, and I have to listen very carefully to hear it. It's not as apparent as before I removed the LED stuff.

 amphead - Sorry to hear you're still having buzz trouble. I'm sure you'll kill it eventually. The silver lining for the rest of us is, once you've solved it, it will help the rest of us avoid the same pitfalls. So, thank you in advance!


----------



## amphead

Torches and pitchforks for you! Runeight warm up the torture device. 

 If anyone decides to go with DC heaters, just ask Ferrari, it adds a "bit" more weight to the amplifier. The voltage regulator needs a xformer with moderate current capability, and that adds weight. The regulator needs a good sized heatsink.


----------



## runeight

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_I'm gonna pull an 'amphead' here and ammend my previous post. Now that it's night time and quieter, I can still hear an etreeeeemely faint hum equal in both channels. It's only audible between tracks, and I have to listen very carefully to hear it. It's not as apparent as before I removed the LED stuff.

 amphead - Sorry to hear you're still having buzz trouble. I'm sure you'll kill it eventually. The silver lining for the rest of us is, once you've solved it, it will help the rest of us avoid the same pitfalls. So, thank you in advance!
	

	
	
		
		

		
		
	


	


_

 

Funch, is it a hum or a buzz?


----------



## amphead

The LM338K cross-references to an NTE935 part #, which I found at Fry's electronics. Fry's also had a 75VA xformer at 24vac, that looks similar to Ferrari's........In fact I'm going to use it and that means another transformer opening in my top plate. Edit: Getting the regulator/heatsink to look good mounted to the top plate will be tricky. I would want the heatsink to radiate from outside of the case. If DC heaters don't solve my problem I'm going to puke. 
	

	
	
		
		

		
		
	


	
















 Edit: The DC heater power will be mounted outside of the case with wire running into the case from a vent hole, for the first test, just in case the noise stays.

 Ferrari's DC heater PS.....


----------



## funch

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Funch, is it a hum or a buzz?_

 

It's an ever-so-faint hum. It doesn't change with the volume setting. As I said in my previous post, it's only audible with no ambient noise present, so it's nothing I'm going to worry about. Just for laughs, I may go back and reinstall D7 to see what happens.

 amphead - How about a burning cross instead?


----------



## amphead

I didn't think they chased Frankenstein's monster with those. 

 I'll be purchasing that 75VA xformer today, since I haven't heard from Ferrari. On another note, I'll be attending the NorCal meet, and my Bijou will be there. I might see Jrossel, who might be bringing his Bijou if he finishes it in time. I will for sure be seeing Amb and drooling on his gorgeous Beta24!


----------



## runeight

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_It's an ever-so-faint hum. It doesn't change with the volume setting. As I said in my previous post, it's only audible with no ambient noise present, so it's nothing I'm going to worry about. Just for laughs, I may go back and reinstall D7 to see what happens.

 amphead - How about a burning cross instead?
	

	
	
		
		

		
		
	


	


_

 

Funch, if it's just a faint hum that's probably heater wiring. If you feel like it, you could try just moving heater wires around to see if anything changes. Mostly getting them away from everything else.

 Jeff told me yesterday that he was listening to his Bijou. You'll have to get him to post his audio opinion.


----------



## MoxMonkey

anyone with a bit more experience into diy know if a hammond 270ex transformer would work? i scavanged one from an old tube amp and am looking to use it for something

 info here

Hammond Mfg. - "Classic" Power Transformer - (263 Series)


----------



## amphead

That's good news Alex! Comparing notes, I might find out something. 

 Bought the 75VA xformer, and once I find a quick source for large capacitor/capacitors, I'll be ready to build the DC power supply for those heaters. My Bijou won't have DC heaters in time for NorCal meet.


----------



## runeight

Quote:


  Originally Posted by *MoxMonkey* /img/forum/go_quote.gif 
_anyone with a bit more experience into diy know if a hammond 270ex transformer would work? i scavanged one from an old tube amp and am looking to use it for something

 info here

Hammond Mfg. - "Classic" Power Transformer - (263 Series)_

 

MoxMonkey I'm afraid that this transformer won't work in the Bijou. It's secondary is 190-0-190 and the Bijou needs a 260-0-260 secondary.

 amphead, i sure hope you can figure something out with the amp. I have my doubts about the DC heater supply, but at this point anything reasonable is worth a try.

 Just remember that when you attach the heater supply to the PS board, the heater bias circuit will try to float the heater supply to 40V. Unless you remove R9 on the PS board.


----------



## amphead

That was something that did concern me and I had hoped to keep R9 intact. If I do remove R9, what issues am I likely to see? Edit: I do realize R9 is attached to one leg of an AC circuit, and I will be changing that to a DC circuit.


----------



## MoxMonkey

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_MoxMonkey I'm afraid that this transformer won't work in the Bijou. It's secondary is 190-0-190 and the Bijou needs a 260-0-260 secondary.

 amphead, i sure hope you can figure something out with the amp. I have my doubts about the DC heater supply, but at this point anything reasonable is worth a try.

 Just remember that when you attach the heater supply to the PS board, the heater bias circuit will try to float the heater supply to 40V. Unless you remove R9 on the PS board._

 

just curious where you saw it having a secondary of 190-0-190? the link shows the 270EX as 275-0-275 unless i'm missing something which is possible


----------



## runeight

LOL. MoxMonkey I don't know. I did look at the transformer page, but maybe found the wrong transformer.

 You can use this transformer, but you'll have to increase R7 and R8 to 470R/5W. At least this would be my first try. Then we'd have to see what the input to regulator actually is.

 Amphead, you just have to ensure that your DC supply can be floated, meaning that no part of the secondary side is grounded anywhere.


----------



## MoxMonkey

cool I thought I was reading it right but I'm new to this so I wanted someone with more experience to verify it 
	

	
	
		
		

		
		
	


	




 thanks


----------



## funch

runeight;4381219 said:
			
		

> Funch, if it's just a faint hum that's probably heater wiring. If you feel like it, you could try just moving heater wires around to see if anything changes. Mostly getting them away from everything else.
> 
> What about covering the heater wires with braided shielding? At this point, rearranging the wires would be nearly impossible. Besides, the hum is so faint, I don't think it would be worth the hassle.


----------



## amphead

I see what you mean. This DC heater power circuit is designed to have the negative side to ground, so floating that 40v instead might not be a good idea.


----------



## amphead

However, is it ok to run the heaters on the amp boards with DC power, while leaving the ez80 on AC heater power with R9 in the circuit?


----------



## runeight

Funch, you could try that. At the low level of hum that you have it might be effective in removing the last little bit.

 Amphead, you can use the DC circuit shown in the schematic that you posted. Just don't ground it anywhwere. Take the two outputs and run them to the PS board just like you are connecting the AC heater wires now. Make sure that no part of the secondary circuit is grounded anywhere. In its box or anywhere else. THen the regulated supply will float, but it will still regulate.

 Could you kindly post another picture of the inside of your build. Thanks.


----------



## pabbi1

OK, so it was late, and I was impetuous... I installed my Obligato caps, that have bare leads on C6, where, had I been thinking clearly, would have covered them with heatshrink. The leads just barely fit the holes, so unsoldering is not my best option without further pain. 

 Any other suggestions about covering this, say, with clear silicon?


----------



## amphead

Runeight, heres the inside view.......This pic doesn't show my sheilded wiring on all signal wires.


----------



## amphead

Pabbi, get some desoldering braid and lay it across the solder joint and apply heat with your soldering iron, while carefully pulling on the caps lead with a pair of needlenose pliers. Apply the desoldering braid to the pad on the board to remove solder from the hole. Install heatshrink on your leads and reinstall. There is a paint-on insulating product, but it might be hard to find. I would not use silicone for this job.


----------



## cetoole

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, get some desoldering braid and lay it across the solder joint and apply heat with your soldering iron, while carefully pulling on the caps lead with a pair of needlenose pliers. Apply the desoldering braid to the pad on the board to remove solder from the hole. Install heatshrink on your leads and reinstall. There is a paint-on insulating product, but it might be hard to find. I would not use silicone for this job._

 

Or just pick up some liquid electrical tape, it works pretty well, and is easy to find. I think I have seen it at Walmart, and I know places like Home Depot have it. I prefer tubing where it works, but am happy with this where tubing isnt easy to do.


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## amphead

Thanks man, thats the stuff that I was going to tell Pabbi about!


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## runeight

amphead;4385215 said:
			
		

> Runeight, heres the inside view.......This pic doesn't show my sheilded wiring on all signal wires.
> 
> QUOTE]
> 
> Looks pretty clean with heater wires away from everything else. Just wanted to have another look. Thanks.


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## amphead

Runeight, I got some information about the reason for floating the heaters from my brother-in-law. One reason that you had them floating was to reduce voltage across the filaments. The filaments are a very narrow wire that has a limited ability to resist High Voltage and might fry without the floating ground.


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## Navyblue

I am thinking of joining the club someday, but probably not so soon.

 I'll probably order the kit. However while I am at it, I might as well use the best parts possible, I'd hate to think I could do X better after I boxed it up. As you probably can tell I do not enjoy constant tinkering. 
	

	
	
		
		

		
		
	


	




 I hope you guys could give me suggestion as to what parts should I replace from the kit (if I should at all). I'd appreciate if you guys could point me in the right direction with regards to the "best" parts (if there is such thing). Especially regarding capacitors, tubes and volume pot. Cost is of secondary issue.

 Thanks.


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Runeight, I got some information about the reason for floating the heaters from my brother-in-law. One reason that you had them floating was to reduce voltage across the filaments. The filaments are a very narrow wire that has a limited ability to resist High Voltage and might fry without the floating ground._

 

Well . . .

 In tubes with separate heaters and cathodes, the very thin heater wire is generally folded over many times and inserted into the cathode sleeve where it indirectly heats the cathode. These tubes were called (still are but we don't pay that much attention anymore) indirectly heated cathode tubes. Some of the big power triodes used in power amps are direclty heated cathodes, i.e., the heater wire is the cathode too.

 The folded heater wire must be insulated from the metal cathode sleeve. This is done by drawing the heater wire through a slurry of ceramic powder with a gluing agent to make a very thin layer of high temperature insulation on the wire. This thin ceramic (metal oxide) layer has very good insulation properties, but it does have a breakdown voltage. That is, the DC voltage difference between the heater wires and the cathode cannot exceed some DC voltage. This is independent of the voltage across the heater itself.

 This voltage is called the heater-cathode (HK) breakdown voltage. You will find it in the tube specs for all indirectly heated tubes. It is usually specified as both a positive and negative voltage. That is, how negative the heater can be with respect to cathode and how positive.

 Now in the Bijou, in the front end the first triode's cathode is at a few volts DC positive. The cathode of the phase splitter is at about 100V DC. But both cathode sleeves are being heated by the same heater wires. This means that the HK voltage seen by the first triode is a few volts while the second triode sees 100V. IIRC the maximum HK for the 6922 is in two parts:

 1. Negative - 135V
 2. Positive - 70V

 This means that the heater can't be any more negative than 135V with respect to the cathode. And it can't be any more than 70V positive.

 Now if we run the heater supply grounded, the first triode is well within the spec, but the second triode is running with a -100VDC HK voltage (heater negative with respect to cathode). 100V is 35V away from the maximum and tolerable. There are likely to be no problems here.

 For the ECC99 the top triode's cathode is at 125V. With the heater grounded the HK voltage would be -125V and the maximum is 200V. Farther away.

 So, there is not a serious HK issue in the Bijou, but the 6922 heater is running fairly high. In order to reduce the HK on the phase splitter, the entire heater supply is put at 40VDC. This places the HK of the first triode a +40V and the second triode at -60V. I felt that it was better to shift the HK voltages a bit, but it was not absolutely necessary.

 Thus, there are two ways to run your DC supply:

 1. Remove R9 and ground the supply 
 2. Leave R9 and let the supply float

 I tried this both ways on my prototype and neither way had any effect. In fact, the last configuration was to have the heaters grounded and I left it this way because the amp is quiet and I didn't feel like putting the heater bias components back into the circuit. 
	

	
	
		
		

		
		
	


	




 Hope this was useful.


----------



## regal

Quote:


  Originally Posted by *Navyblue* /img/forum/go_quote.gif 
_I'd appreciate if you guys could point me in the right direction with regards to the "best" parts (if there is such thing). Especially regarding capacitors, tubes and volume pot. Cost is of secondary issue.

 Thanks. 
	

	
	
		
		

		
		
	


	


_

 


 Use a Nichone Muse KZ for the cathode bypass.

 Use your film caps of choice for everything else if you have high ohm phones.
 The main coupling cap will have to be electrolytic if your phones are lower than 300 ohms. You will also have to use the NFB with low ohm phones, otherwise delete it.

 A few pages back I posted the recipe to bias the 6922's to 5 mA's. This mod takes the Bijou to a level above the DV337 in direct comparison (via AKG Sextetts.) You'll need ECC99 tubes and a EZ81. There are resistor changes too.


----------



## Navyblue

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Use a Nichone Muse KZ for the cathode bypass.

 Use your film caps of choice for everything else if you have high ohm phones.
 The main coupling cap will have to be electrolytic if your phones are lower than 300 ohms. You will also have to use the NFB with low ohm phones, otherwise delete it.

 A few pages back I posted the recipe to bias the 6922's to 5 mA's. This mod takes the Bijou to a level above the DV337 in direct comparison (via AKG Sextetts.) You'll need ECC99 tubes and a EZ81. There are resistor changes too._

 

Thanks for the recommendations, however please bear with me as I am not well versed in amplifier design and terminology. I still have some way to go before I could get my hand on these and not literally fry myself.

 Which is the cathode by pass? C2? 
	

	
	
		
		

		
		
	


	




 Which is the "main coupling cap"? C5? 
	

	
	
		
		

		
		
	


	




 Why does it have to he electrolytic for low Z phones? Aren't these supposed to be inferior to film? I'm using 120 ohms K501, so I guess NFB remains necessary.

 So I guess it would be an overkill if I use film for all capacitors (assuming the value is available)?

 So, I guess it hasn't been tested that there is enough juice to apply the 5 mA bias mod along with the 6N6P as Runeight proposed? Would using a more powerful transformer requires further alteration of the circuit?


----------



## runeight

regal, i would like to put your mod onto the Bijou website. I know that you posted them mod a while back, but would you be willing to email me with the changes?

 I think I know what they are, but I want to be sure to capture all of them.


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## amphead

Bravo on the explanation of the heater PS circuit! That helps tremendously, to visualize what is going on.

 Navyblue, congrats on choosing the Bijou!

 NorCal meet right around the corner!


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## runeight

Quote:


  Originally Posted by *Navyblue* /img/forum/go_quote.gif 
_Thanks for the recommendations, however please bear with me as I am not well versed in amplifier design and terminology. I still have some way to go before I could get my hand on these and not literally fry myself.

 Which is the cathode by pass? C2? 
	

	
	
		
		

		
		
	


	




 Which is the "main coupling cap"? C5? 
	

	
	
		
		

		
		
	


	




 Why does it have to he electrolytic for low Z phones? Aren't these supposed to be inferior to film? I'm using 120 ohms K501, so I guess NFB remains necessary.

 So I guess it would be an overkill if I use film for all capacitors (assuming the value is available)?

 So, I guess it hasn't been tested that there is enough juice to apply the 5 mA bias mod along with the 6N6P as Runeight proposed? Would using a more powerful transformer requires further alteration of the circuit?_

 

Yes, the cathode bypass cap is C2. The main output coupling cap is C5. It's high frequency partner in parallel is C6.

 It's the size in uf of the capacitor that matters for different headphones. The lower the impedance of the headphones the bigger the capacitor must be to achieve good low frequency response. For 32R phones a big electrolytic is almost certainly required. For 300R headphones, a smaller film or paper or whatever capacitor may work just fine. For 120R it will just depend on where you want the bass to roll off.

 It would not necessarily be overkill to use film caps if you can provide a good value in all locations. In fact, if we had really big film caps we would dispense with the electrolytics altogether.

 So far as I know the 5mA mod has only been tested with ECC99 output tubes. MHO is that it might work with 6N6P output tubes, but someone will have to give this a try. However, if the amp is performing the way Regal says it is, then it's hard to see how using 6N6Ps will make that much difference. But, you never know. 
	

	
	
		
		

		
		
	


	




 Using a transformer with a higher HV secondary might be needed, but I don't think so at the moment.


----------



## Navyblue

Thanks all for your guidance, however I'd probably need a lot more when I get my feet wet. 
	

	
	
		
		

		
		
	


	




 So what's the reason for people to want to run 6N6P instead of ECC99? I think I read somewhere that the current is too low for it to run at an optimal level? Please correct me if I am wrong.


----------



## pabbi1

Ok, just a little bump, with a little pron:

Amp boards

The final board layout

 Any comments about wire routing, and where I am likely to need shielding? Acquired some 2ml copper foil tape, so I assume the input from XLR to pots, and?


 If I could ever order the correct C5 - lessee, 47uF 450v... nope. 470 uF 450v... uh, no. 470uF 250v incoming... <sigh>.

 Ok, getting close enough to start worrying about the inevitable... when I flip the switch to check power... to wit, test both at the same time, or one at a time? I do have two meters.


----------



## runeight

Wow, that's a lot of boards. But it looks great. 
	

	
	
		
		

		
		
	


	




 If it were me, I would bring up the PSs one at a time. such that the AC was applied only to one at a time. Then I would test heaters on the amp boards and THEN attach B+.

 I think that the way to do the grounding is to connect the input ground for the pair of boards making one channel together between the boards. And then run this to the star. Same for the output ground at the O/P tube terminal block.

 Then I'd run the xlr ground to the boards where they are connected together.

 You've probably already thought this through, just thought I'd offer some ideas . . .


----------



## pabbi1

Unfortunately, I have probably overthought the ground...

 Ok, so the ground from the XLR in is not yet grounded, so, do I need to tie this to the pot first, then run that to the input ground? My attenuator only showed output to ground, so I am confused - there is no seperate input and output for ground, so I didn't see the point.

 And, do I need to explicitly also need to run the XLR input jacks themselves to star, or is that unnecessary?


----------



## amphead

You're moving right along. Don't forget to put the load resistor on the PS boards before testing. I know that you know that, but thought I would mention just in case.

 Well, I listened to 2 quiet Bijous at the Norcal meet Jeff's and Simon's, where they are using the NFB circuit. Simon brought a quality Fluke meter and looked at quite a few test points where all appeared normal. There is of course the fact that on my amplifier NFB has been removed, and I'm using 64 ohm phones. Maybe It's not possible to get complete silence under these circumstances. I picked up another set of boards from Jeff and so I'll build another PS with some different sourced parts and see what I find. DC heater supply build will be happening soon, and I'll try removing R9 tomorrow, and grounding AC heaters with a pair of 100 ohm resistors, just to see what it sounds like, since you have given me the go-ahead Runeight.


----------



## bhjazz

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I think that the way to do the grounding is to connect the input ground for the pair of boards making one channel together between the boards. And then run this to the star. Same for the output ground at the O/P tube terminal block._

 

I would think about how to arrange the boards such that it simplifies wire bundles. Something similar to what you have with the two amp boards that, in the photo, are in the lower right hand corner. Arranging the other two in a similar fashion would allow you to route wire bundles between the two pairs of boards, then you can split off pairs of wires as needed. 

 2 cents!


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## runeight

pabbi1, let me add more detail to the grounding scheme. A picture would be better, but maybe I can describe it.

 One channel.

 Connect the In G on the two boards together. Connect the Star G (at the input terminal block) together. Connect the Star G (at the ECC99 terminal block) together.

 Connect the signal pairs from the XLR to the vol pot and then on to the In connections on the boards. Connect the ground from the XLR to the vol pot to the In G of the boards.

 Connect the outputs of the board to the XLR. And connect the ground of the output XLR to the Star G of the ECC99 block.

 Does this make sense?


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## pabbi1

Yes, that helps immensely.

 Now, for the final caps to get here on Wednesday, and fire this puppy up on Friday - or Thursday night with all the other fireworks.


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## miky

It is worthwhile to change (upgrade? 
	

	
	
		
		

		
		
	


	




) some resistors? If so which ones?


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## regal

I have heard some like to use higher quality cathode resistors on tube amps, never tried it though. I would spend my money on film caps first.


----------



## amphead

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_It is worthwhile to change (upgrade? 
	

	
	
		
		

		
		
	


	




) some resistors? If so which ones?_

 

Miky, some consider it to be an upgrade to use prp resistors instead of vishay-dale. Don't know that to be true myself. They look great with the red outer color against the green pcb.


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## miky

Thanks, PRP it is easy (for my valet) upgrade 
	

	
	
		
		

		
		
	


	




. There are others "critical " places?
*regal* can I use 470Ω instead of 487Ω in R2?


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## amphead

[size=large]EUREKA![/size] Problem solved......................... [size=xx-large]FOREVER![/size]
	

	
	
		
		

		
			










































































 Chuck those DC heater power supplies into the garbage can! Everyone, everywhere who has built a Bijou with NFB..........Go to the page that shows how to remove it and do it! Remove R9 from the Power Supply. Next buy 2 quality 100 ohm 10W wirewound resistors at Radio Shack or similar. Attach one end of each resistor solidly to your star ground. Solder a wire to the other end and insulate. Attach each wire to the legs of your heaters coming off the xformer. You now have a BLAAAACK background for ALL positions of your volume pot!!! With music off, I could hear an ant piss at 100 yards. As long as this doesn't reduce the life of the tubes significantly, then it's a WINNER!! Now I can concentrate on the aesthetics of this build. More LEDs etc.  Thanks ALEX for creating this lively gem. PERSEVERANCE WORKS!


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## Navyblue

Congratulation, I can feel the relieve.


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## regal

Amphead, you did two things at once. I have no buzz/hum with R9 in place, but I never installed the NFB.


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## runeight

Wow, that's really great news amphead. 
	

	
	
		
		

		
		
	


	
















 I can feel the relief too because I know that this amp can be dead quiet.

 This is not a bad mod to make and it will not harm the tubes because they are operating within HK specs.

 Now you can listen. And I'm very interested to hear your impressions.

 This is just great. As I posted in a previous message, I have admired your persevearance with this problem. It's also a great help to others building the amp and i may just change the website instructions if everyone gets as good results.


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## regal

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_Thanks, PRP it is easy (for my valet) upgrade 
	

	
	
		
		

		
		
	


	




. There are others "critical " places?
*regal* can I use 470Ω instead of 487Ω in R2?_

 

It depends on the tube you're using. With 487 ohms it put the operating point in the middle , good for aged vs new tubes. You can try it and see if you have the required 100V +-5 at the plate. Probably no problem but test.


----------



## bhjazz

Hey amphead - good job. Could you clarify, though? In one post you said you were not using NFB, and just above on this page you are suggesting a mod for builds with NFB. Uhm...I'm confused! (maybe it's that two hour meeting I just got out of...!) Can I use this with NFB, or shoudl I just exclude that from my own build?

 Thanks!


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## MoodySteve

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_[size=large]EUREKA![/size] Problem solved......................... [size=xx-large]FOREVER![/size]
	

	
	
		
		

		
		
	


	









































































 Chuck those DC heater power supplies into the garbage can! Everyone, everywhere who has built a Bijou with NFB..........Go to the page that shows how to remove it and do it!_

 

Congratulations! Can you go into more detail about removing the NFB and heater power supplies? I didn't see anything on Cavalli Audio about that. I think I'm keen to try this mod when I get around to building mine. Thanks again!


----------



## runeight

Good questions all. Gents I will post amphead's heater mod on the Bijou website later this evening (Texas).

 MHO is that you can run with or without NFB with these heater mods and get the same quiet. This is because NO NFB is the worst case for the noise. Any amount of NFB reduces the noise. So if the amp is quiet with no NFB then it will be quite with NFB.

 However, amphead is probably refering to the dynamics of the amp with the NO NFB mod that is shown on the website. This is because the no NFB mod improves the high frequencey response of the amp giving it a bit better transient response.

 MoodySteve the NO NFB mod is on the Tweaks page near the bottom.


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## runeight

OK gents, Amphead's heater mods are posted to the Bijou website. Find the Tweaks flyout menu and you'll see the selection at the bottom of the flyout. The Removing NFB tab is there also. Everything you need.


----------



## amphead

Quote:


 This is because the no NFB mod improves the ultra-sonic response of the amp giving it a bit better transient response. 
 

Yeah, I just couldn't get the sound that I like the most, with NFB. So, unless your phones are just too low of an impedance to work, then eliminating it is a plus.(JMHO)
 As you have clarified Runeight, the two are completely separate mods. The R9/100R mod and the NFB mod.
 Thanks guys for the support. This is just a slam dunk, that can not fail you. Thanks for posting the mod on your web-site. Ferrari is correct, when he said that it is a known grounding method, but sometimes finding what you need doesn't come easy.  I'll post my sonic evaluations soon.


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## runeight

Yes it is, and was, a very common technique for relieving hum. Often the two resistors were a pot with wiper to ground that was dailed in to get minimum hum.

 I am thinking on why this has made so much difference in your amp. No answers yet, but some theories.


----------



## amphead

Yes, it's somewhat of a mystery. I didn't remove R10 and C7. Do you think I should?


----------



## runeight

I would remove C7 because its positive terminal is now tracking the heater AC both positive and negative. It will eventually be damaged - now that I think a bit more about it. In fact it may turn into a short fairly quickly so you might want to remove it right away. I'm going to recommend this on the website too.


----------



## amphead

And R10 is no longer necessary as part of the voltage divider.


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## runeight

No, it's an appendix now. But you can leave it in or take it out. It doesn't really affect anything.


----------



## funch

amphead - congrat's, and thanks (again). Your solution has benefited us all.

 runeight - I have installed the extra heater tranny to run the 6H30 inputs following the diagram you posted some time back. Can I implement this mod with my configuration?


----------



## runeight

Probably so. Can you remind me which drawing that was?


----------



## funch

Here: HeadWize: DIY Workshop > Bijou All Tube Futterman Headphone Amplifier - Release
 Message #111.


----------



## chobint

grats amp, been following the saga since page ~20.

 So I recently ordered a bijou kit from glass jar and picked out nearly everything besides wires. I was considering ordering the Kimber TCSS Varistrand Internal Hookup Wire, stranded #19 AWG from angela.com since i haven't ordered my 370DAX yet from there yet. Had a few questions though:

 1)Would those kimber wires be of sufficient specification and quality for the bijou?
 2)Does it matter that the kimber is not the exact 20/22awg specified on the bijou page? Not sure if relative resistance in the wire is even measureable over such a short length
 3)Will more expensive hookup wire even show noticeable improvement over plain old radio shack wire considering relative mediumish quality of my other components (using jeff's kit plus the parts listed below).

 Stuff I've ordered or plan on ordering listed below.
Neutrik Silver Locking 1/4", Dayton Gold RCA Jacks (pair), IEC Power Socket, 12 slot terminal, Hammond 370DAX.

 thanks


----------



## runeight

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_Here: HeadWize: DIY Workshop > Bijou All Tube Futterman Headphone Amplifier - Release
 Message #111._

 

Oh yeah. The mod will work but you'll have to do this:

 1. Connect the Auxilliary Transformer to the PS board as per normal. You shouldn't have to change the resistor bias chain at all.

 2. Disconnect the Hammond 270DAX heater winding from the PS board entirely.

 3. Put the 100R resistors onto the 270DAX heater secondary connected to ground.

 4. Hook the 270DAX heater secondary to the amp stages as per normal.

 It shouldn't bother the amp for the rectifier's heater to be biased to 40V. I'm pretty sure it's the amp heaters that were injecting the noise.


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_1)Would those kimber wires be of sufficient specification and quality for the bijou?
 2)Does it matter that the kimber is not the exact 20/22awg specified on the bijou page? Not sure if relative resistance in the wire is even measureable over such a short length
 3)Will more expensive hookup wire even show noticeable improvement over plain old radio shack wire considering relative mediumish quality of my other components (using jeff's kit plus the parts listed below).

 thanks_

 

Well, if kimber wire is just really nice 19awg wire then there should be no problems except that you might have some trouble getting multiple wire ends into the terminal blocks. You'll have to see about this.

 But, your wire should have at least 600V insulation rating. If it doesn't I would not take a chance with it.

 I don't use Radio Shack wire. I just try to buy good coated solid hookup wire. I know that others feel strongly about wire and in certain situations such as long speaker runs or inter-amp connections, good wire is really important. But inside the box where the runs are typically short, MHO is that just good quality wire is good enough.


----------



## ericj

I used military surplus PTFE-insulated* silver-plated wire, 20awg for heaters, 22awg for everything else. It was cheap because i bought it by the pound. 

 *("Teflon(r)" is a registered trademark of Dow Chemical and refers to a whole family of fluorinated polymers, all of which are inferior to good old polytetrafluoroethane - which is also, but no longer excluisively, marketed under the "Teflon(r)" brand.)


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## amphead

I think that I notice a small increase in detail with the milspec Teflon wire. The signal traveling on the silver plating "might" be making a difference, as well as Teflon damping vibrations on the wire. This wire just will not degrade either, and would still be working well into the next century. "Silver wire", for those not wanting to plunk down the big money. Just my theory.


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## Navyblue

Would it be a good idea to swap the main volume knob to a 10k ones?


----------



## chobint

sigh...scoured the internet dry and no info on the kimber wires. The closest thing that I found to an indication of voltage rating is its usage in this DIY Fidelity DIY tube post, but the guage and voltage aren't specified 
	

	
	
		
		

		
			





. Sadly everything on mouser, newark and digi is a bit too long, and parts express only offers generic 16awg stranded. Can anyone suggest a trusted source for affordable solid core wires? I'm not picky, I would go just go with the 600v radio shack solids...if they weren't 12ga
 thanks


----------



## amphead

Here is an ebay source for what you want>

ORANGE 20 AWG SOLID TEFLON HIGH TEMP WIRE 200FT - eBay (item 110266291712 end time Jul-06-08 08:00:45 PDT)


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## funch

Here's another:Radio Daze. Click on 'components', then scroll down to the wire listing.

 I used their stranded 600V wire for the PS/heater wires. Good stuff.


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## runeight

I use this Carol hookup wire from Digikey. It's not terribly expensive and meets the need. I use the style 1015, 105d, 600V wire. It comes in lots of nice colors.

Carol Wire

 A couple of reels of 22awg wire will last a long time and a few projects.


----------



## chobint

Thanks for the suggestions. I didn't even think about ebay. I think I'll be patient and wait for the auction to expire, despite the temptation to order now from digi\radiodaze


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## amphead

My amp is sounding the best ever, and I haven't even upgraded my bypass caps yet.......to Obliggato, Auricap etc. Now this might sound far-fetched but consider this. When I did the mod to ground the heaters with the 100R resistors, the sound signature seemed to have suffered. After burning the amp in again with the new configuration, the sound has "opened up" once more, with incredible detail. With the heaters floating, the tubes are burned-in at a different HK voltage, than when they are grounded. This might explain why it sounds so good right now, compared to my earlier sessions.


----------



## regal

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_My amp is sounding the best ever, and I haven't even upgraded my bypass caps yet.......to Obliggato, Auricap etc. Now this might sound far-fetched but consider this. When I did the mod to ground the heaters with the 100R resistors, the sound signature seemed to have suffered. After burning the amp in again with the new configuration, the sound has "opened up" once more, with incredible detail. With the heaters floating, the tubes are burned-in at a different HK voltage, than when they are grounded. This might explain why it sounds so good right now, compared to my earlier sessions._

 

No the heaters see the same voltage as before. If they didn't your tubes would blow up.


----------



## fordgtlover

I have just finished the amphead heater mod.

 The mod has improved (slightly), the background hiss as I turn up the NFB.

 While it isn't a 'black & white' improvement, it is still a worthwhile improvement.

 Small tweaks add up to big gains 
	

	
	
		
		

		
			





 Thanks amphead - nice job.


----------



## indikator

runeight, in your website parts list R4,R8,R10 are 301Ohms but in the schematic they are 300Ohms, is it typo?


----------



## runeight

No, it's not a typo, but perhaps I should make it consistent.

 300R is what I generally like to use for grid stopper resistors. This is a standard value for the Mouser Xicon 1% resistors.

 However, the Vishay RN55D resistors have a standard value of 301 Ohms. Since the board resistors are sized for the RN55D I just listed the Vishay stock value in the parts list.

 But, you can use either one. The 1 Ohm won't matter at all to the amp's behavior.


----------



## GeWa

Ordered me some 6N1P(20x) and 6N6P(8x) tubes from Ebay for my Bijou (if it gets finished).

 Regards


----------



## amphead

Quote:


 *Runeight* - The folded heater wire must be insulated from the metal cathode sleeve. This is done by drawing the heater wire through a slurry of ceramic powder with a gluing agent to make a very thin layer of high temperature insulation on the wire. This thin ceramic (metal oxide) layer has very good insulation properties, but it does have a breakdown voltage. That is, the DC voltage difference between the heater wires and the cathode cannot exceed some DC voltage. This is independent of the voltage across the heater itself.

 This voltage is called the heater-cathode (HK) breakdown voltage. You will find it in the tube specs for all indirectly heated tubes. It is usually specified as both a positive and negative voltage. That is, how negative the heater can be with respect to cathode and how positive. 
 

Just to clarify, if you see what Runeight says here, I'm not referring to the heater voltage.......my mod changes the HK voltage. I might add, congrats on discovering the current mod for the Bijou Regal. Oh, and congratulations on getting Headphoneus Supremus! 
 More pics of this beauty?






 Thanks Fordgtlover, It could be that the heater mod works best with NFB removed. I have not tried using the heater mod with NFB still in the circuit.

 GeWa, I'm looking forward to your listening impressions when you finish your Bijou. I wondered where you were lurking.


----------



## runeight

That's a really nice build amphead. It's what I had in mind when I made the boards. An old style tube type amp. 
	

	
	
		
		

		
		
	


	




 Perhaps, after some listening time you can tell us how the amp is making music.


----------



## indikator

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_No, it's not a typo, but perhaps I should make it consistent.

 300R is what I generally like to use for grid stopper resistors. This is a standard value for the Mouser Xicon 1% resistors.

 However, the Vishay RN55D resistors have a standard value of 301 Ohms. Since the board resistors are sized for the RN55D I just listed the Vishay stock value in the parts list.

 But, you can use either one. The 1 Ohm won't matter at all to the amp's behavior._

 

ooo I see, so one should be okay using the value in schematic, 
 thanks for the answer


----------



## amphead

Sorry, I wouldn't mind claiming Regal's chassis as my own, but I was asking Regal if he could post more pics of his build.  I'm thinking about creating a backlit Bijou logo. Here's how I would do it. The front panel would get a matrix of six Led's, three followed by another three underneath. These would probably be blue Led's. Then I would create a transparency on clear plastic that reads Bijou in an artistic font. The transparency would be mounted behind a badge mounted in the center of the front control plate. The badge would be a piece of black plastic with a rectangular cutout in the center. Then a rectangular piece of clear plastic would be cemented in to that hole, with the transparency behind it. When powered on the system displays its backlit blue moniker. Edit: also a thin white plastic piece to diffuse the light behind the Bijou logo. Edit: maybe font like this......... 





 or ..........


----------



## runeight

You know, with all of the noise issues we've been messing with, I'm forgetting who's build is who's.

 I like the font. It's very similar to what I used on my FPE top plate. You can find this on the Bijou website on the point to point page.

 I'm not able to see the image you attached.


----------



## amphead

If anyone else has an idea for the Logo/Badge........let me know what you're idea is. Nothing written in stone for me yet.


----------



## GeWa

Which font type is the first one?

 Regards


----------



## runeight

amphead, now that I can see both fonts, I like the first one better.


----------



## pabbi1

I also like the first font best - IFF I would ever get the right size caps... 22mm not 35... <sigh> Had hoped they would be here today, but, no. Most likely Monday.


----------



## amphead

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_Which font type is the first one?

 Regards_

 

GeWa, the first font is called cuisine. I don't own the font set, but because I only needed a sample, I was able to get that one.


----------



## amphead

I'm still tweaking tone, since the buzz is gone. Therefore, just to see what it would do, I added a 25 ohm 3W humpot to the circuit. I attached the wiper of the pot to star ground and lifted my 100R resistors from star ground and attached one to the high side and one to the low side of the pot. This appears to improve the tone somewhat. I dialed the pot to 13.4 ohms per side to ground, which centered the wiper. It's a mystery as to why the sound gets clearer, but I would call it a tweak. It's also something that I recommend for builders to try if you still have some noise with the heater mod. It puts my heaters at 113.4 ohms per side, referenced to ground. I'm not sure what the effect is to increase resistance from each leg of the heaters to ground. I understand that the heater mod is supposed to differentially cancel noise from one side of the heaters to the other.


----------



## runeight

Well . . . many things happen in the world of audio.

 But I am surprised that there is any noticeable difference at all. The incremental change to the heater circuit is very tiny and likely swamped by what else is going on in the PS and Amp.

 The only thing that is changing when you change the resistor values is the amount of current drawn from the heater secondary through the resistors. At 100R the AC current is about 63mA. This is a non-trivial draw from the secondary, but not serious compared to the total heater current. 

 Changing the resistance to 112.5 (or 113.4) makes the draw 56mA (55mA). 

 So, I guess I don't really understand this either. 
	

	
	
		
		

		
			





 But, if you want to do more experimenting try using a single 100R pot with no fixed resistors. Maybe you'll get different results with this configuration.


----------



## amphead

Since, I want to try the mod with more current tonight, I'll replace each 100R resistor with two 22R in series, effectively doing the same as a single 100R pot. The only thing that we can be sure of with this voodoo, is that this will increase the available electrons to make tube current, even though the biasing resistors are establishing current flow through the tube.


----------



## amphead

So, with the total of 22R + 22R + 13R4, there is 57.4 ohms per side to ground. There is a slightly more full sound, than before. It is still clear though. Here is my theory, the pot has a single point of reference to star ground with the wiper making contact there. This makes it clearer. Now with the increased current flow through the heaters, dynamic response/presence seems to increase slightly with a fuller tone, "possibly" due to the greater number of electrons boiling off. I need more time to see if this impression holds. Edit: the sound is more "forward", and I might prefer it more "laid back". Chassis runs warmer, probably more than I would prefer. 

  Quote:


 At 100R the AC current is about 63mA. This is a non-trivial draw from the secondary 
 

Yes, and I'm going to recommend not going lower than 100 ohms per side. Seems that it just gets too warm and might prove to be a point of failure for the tubes. And on the "very extreme" other end, too few electrons could result in cathode etching, but that's not likely to happen with any reasonable heater bias. But it is what happens with High Voltage and zero heater current.


----------



## amphead

55mA sounds the best to me and is the most musical, for heater current bias. So about 113 ohms per side. This is where my chassis temp is reasonable too, so its the winner. The easy config is 25 ohm 3W pot plus 2 wirewound resistors at 100 ohms each. All easily available. Edit: this configuration still has plenty of punch, without getting the overdriven/distorted punch that 57 ohms per side produces. And it's dead quiet. All of this based on K701 at 64 ohms, no NFB, so take that into consideration.


----------



## amphead

Just need to work on the badge/logo now, and find some upgrade bypass caps. The wimas/polypropylene are OK, but I would like just a little more.


----------



## amphead

Badge/Logo starts tomorrow. I am considering Mundorf M-cap silver/oil which have a reputation for liquidity but not detail. Expensive. On the other hand I am considering Audio Note copper which have a reputation for detail/liquidity/perfection. More expensive. Edit: if you live in the temperate zone of the U.S., it's time to get out of the swimming pool and help me dial in the Bijou to the "nines".  If it's cold where you live.....Belgium then help appreciated too.  Edit: some tube amps have a syrupy signature. That's the direction I want to go, but would say I have a neutral/detailed signature at this stage of the game. On the other hand I have just tried the Koss/Test-phones for a different perspective, and the Bijou changes right along with the phones, away from a neutral signature.


----------



## dBel84

amphead: I had this idea for a logo but haven't messed about with it enough yet, I added your font as I did like that. If the idea appeals, perhaps you can have a go at refining it..dB


----------



## pabbi1

I think more the gracefully curved glass, a la the raytraced 
 6z4, or some wilder jazzy tube from the bygone era... alas I no longer remember POV, nor the source to this to somehow impose Bijou somewhere.


----------



## dBel84

that's the underlying concept but bringing in the "jewel" to represent Bijou , the image seems much wider posted than it does on my screen, it needs to be narrower and much smaller ..dB


----------



## pabbi1

The proportion threw me... wonder about laser scribing into my wood panel? Too bad I have 9 coats of tung oil on already.

 As an aside, caps are all in, and I'll QC all the joints tonight, then power up if I feel confident all is well. Power only tonight, amp boards tomorrow.


----------



## dBel84

this was the original font I tried






 I will make time to work on it at some point, unless someone else comes up with a killer logo that I will have to use  ..dB


----------



## amphead

The idea of using a gemstone with the Bijou font is appealing to me. I think trying to get all three ideas with the tube as part, will be a stretch to accomplish.

 Maybe something like this.....


----------



## pabbi1

Pretty appealing - doubt it is scribable - maybe decals?


----------



## runeight

Very nice logo gentlemen. This saga gets more interesting every day. 
	

	
	
		
		

		
		
	


	




 Pabbi1 I'm looking forward to your balanced amp. It will be the first balanced Bijou.


----------



## dBel84

Looking good amphead but too complex for me to duplicate on a metal shell. 

 I was doodling on the bus on the way home and I think I have found what I was looking for :







 ..dB


----------



## chobint

I was imagining something like the LED's reflecting off water onto the semi-transparent film would be cool...but we can't exactly put moving water into our amp now can we : \ I know there are little spinning lamps like http://cache.gawker.com/assets/image...style-lamp.jpg that use a spinning plastic shield to create the effect





 Or something like the way pumpkins are carved, except it would be carved into plastic of some sort with the LEDs showing thru, in the gem pattern with the bijou letters.




 except with letters like




 would definitely make for a one of a kind piece, but probably unreasonable to implement, oh but a man can dream...


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Very nice logo gentlemen. This saga gets more interesting every day. 
	

	
	
		
		

		
		
	


	




 Pabbi1 I'm looking forward to your balanced amp. It will be the first balanced Bijou. 
	

	
	
		
		

		
		
	


	


_

 

Me neither - running behind on my QC, so power up waits until tomorrow.

 Once this is up and running, I can compare the world's only balanced Millett Max (with an OPUS dac) against the balanced Bijou (running through the Azur 840c)... and, just to make the farce complete, I am sorely tempted to balance out a Millett Starving Student - all the parts are in house... 
	

	
	
		
		

		
		
	


	




 Edit: Well, assuming I can finally do a p2p.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_The idea of using a gemstone with the Bijou font is appealing to me. I think trying to get all three ideas with the tube as part, will be a stretch to accomplish._

 

Nice ideas. You are desperately close to a few ideas that are tossing around in my head, and I think the gemstone idea would be cool to explore. 
 FPE would be a great place to get etching done for our causes/cases here. I think they currently have 23 fonts available in the software. And lets face it: a black panel with silver lettering would look sweet! I think manipulating the shape library they let you use could net a pretty cool design. I suppose, though, the real cost is not dollars, but time, in this case. Oy.


----------



## amphead

Quote:


 Running heaters under-voltage is therefore perfectly acceptable, and provided the voltage isn't too low there will be no noticeable difference in sound. Normal heaters rated at 6.3V can be run quite happily between 5V and 6.9V, maybe even lower, but not higher. The exception to this rule is rectifier valves, which should not be run below 10% of their rated voltage since they usually operate very close to saturation. 
 

Found that information at a site called "The Tube Wizard". It's not directly related to the current mod, but was interesting.

 If we work for a line drawing of the gem and add the font, that could be etched into wood or metal. I like some angular lines to the inside parts of the gem outline, representing the facets that reflect internally.


----------



## amphead

How about this one------->


----------



## pabbi1

Can you do that to include the plug thingie - a nod toward the tube nature of the amp?

 Otherwise, lovely. And, laser scribable.


----------



## holland

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_How about this one------->_

 

Out of curiosity, what would it look like rotated so you see the top down with "Bijou" inscribed in the middle? Assume a round cut.


----------



## amphead

Holland, I tried the top view of the Gem and it was too plain looking to me.

 How about this........


----------



## V-DiV

How about a gem shape with the word Bijou in it, all inside a graceful old tube shape like pabbi1 suggested. Something like this. (I wish it would show larger).

 Cheers,
 Vic


----------



## amphead

Interesting. Let's see what the response is for our creations.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_How about this........




_

 

I am digging that... the old tube I had is a ray trace (computer rendered image), and simply not easily reproducable in scribing / machining, but would be ok as a decal. I like this a *lot *as a scribable line art image.


----------



## dBel84

This is looking great, what is the resolution of the image that you are working from ? In other words, will this make a clean laser print? ..dB


----------



## amphead

248 x 194 pixels. If that wouldn't be enough, I could create a larger image with more resolution.


----------



## amphead

HaHa.......Thought I had tubes or caps going out on me. Very thin hollow congested tone. The plug to the phones wasn't fully pushed in. Amazing that I even had sound both L/R.  Edit: back to that jewel like tone with a little Deardorf, Portal Jazz(Highly Recommended). This was recorded with such incredible clarity. Saxophone, piano, horns, jazz guitar, double bass, cymbal chrashes, snare.....wonderful! If I work up the nerve to purchase a pair of the Mundorf Silver/Oil 1uF 1200v....... Edit: what other values for bypassing the output caps, have you tried Runeight? 2.2uF, .45uF, .22uF ..... and with what sonic impressions?


----------



## runeight

Amphead, there are so many interactions it's hard to say on the output caps.

 But, generally, the bigger the film cap the lower the frequency will be where it will pass some of the O/P current. It will never pass all of it, even if it's as big as the electrolytic. The larger it is, however, the more low freq current will flow through it.

 Now what this does to the sound is hard for me to say.

 You'll just have to try it and see what you like.

 We can say, however, that if we could replace the electro with a film cap entirely, we'd probably get really nice results.


----------



## Ferrari

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_...
 We can say, however, that if we could replace the electro with a film cap entirely, we'd probably get *really nice results*. 
	

	
	
		
		

		
		
	


	


_

 

You have read my mind.


----------



## amphead

Looks good Ferrari!

 The reason I mentioned 2.2uF bypass, is that if I went with Mundorf silver/oil I'm imaging lush compared to 1uF Mu s/o. But maybe just too boomy.


----------



## runeight

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_You have read my mind. 
	

	
	
		
		

		
		
	


	


_

 

Ferrari that is one really nice looking amp. Have you had it working yet?


----------



## runeight

BTW gentlemen, what are you planning to do with that nice artwork a few posts back?


----------



## amphead

I think some will be etching the design into metal, and others will laser-scribe it into wood on the chassis. In my case, I create a backlit logo/badge for the front panel, as described earlier. I talked to my brother-in-law about bypass caps and he feels I should just stick with 1uF, and get the Mundorf silver/oil, if I can find them reasonably priced.


----------



## amphead

Still not sure, what bypass caps I want yet. Reading reviews turns you upside-down, sideways and rightside-up again. On another note, the system seems to have twice the soundstage, musicality, liveliness and depth that it had yesterday, without doing anything to it. Burn-in? Confusing to say the least. Yesterday, I knew that I was listening to a device, and today I feel like I'm at the performance. It slows me down a bit on ordering bypass caps.(yes just MKP Wimas in there right now) Edit: once again World-Class sound, without any extra whistles and bells yet. And dead quiet  I can hear some of you saying....Stop!.....Don't touch it.....If it's not broke, don't fix it. You finally got it the way it's supposed to be.


----------



## runeight

The amp does break in, particularly the tubes. About 50 hours on them seems to be a typical number from other people's experiences.


----------



## Ferrari

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Ferrari that is one really nice looking amp. Have you had it working yet?_

 

The electronics was up and running since the prototyping phase begin this year. I have added some modifications into this amp but basically it's the Bijou. I have taken it apart to do the case work but due to the crazy work schedule lately I still can't find a chance to finish it.


----------



## koike

just a contribution...i liked the clean look which ferrari had and hope to have something like that. this is my take on it.


----------



## regal

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_You have read my mind. 
	

	
	
		
		

		
		
	


	


_

 


 Yes it is very possible to use film caps and not too expensive to use film caps on phones over 300 ohms. 60 uF should be fine for AKG 240's and probably Senn 580/600/650.


----------



## amphead

On E-bay, there is a seller called maxwellaudio. They had listed 1uF Mundorf supreme silver/oil 1200vdc, but the description read .47uF. When I pointed that out, they offered me free shipping. That was just enough of a push, so........those will get here in about 9-10 days. Break-in on those is about 200-250 hours. Edit: the obligatos were actually rated half a point better by another Head-fier. So you will be a happy camper Pabbi. This will give us a wide area for reviews though since many of us have gone in a different direction. The auricaps, obligatos, mundorf, audyn, ft-3 etc...although the real interesting reviews are going to be between balanced build and uber audyn film cap build.


----------



## amphead

Quote:


 I really did not know what to expect from these. Some people's reports mention things like "liquidity" and "smoothness," which led me to believe these would share a rather pleasant but not kick-you-in-the-groin resolution or power. Boy, was I wrong.

 If push comes to shove, words like liquid and smooth *are* applicable, but there is so much more. The calling card of Mundorf SIO seems to be infinite shades of resolution riding on the oh-so-smooth sonic flow. There is enough detail for even detail freaks like me, and those who value life-like dynamic range and punch would love these as well.

 Compared to other metallized poly caps, Mundorf SIO seems to be at least 2-3dB louder(!) at the same volume setting with punch that slams harder and truer. 
 

That was the review by another Head-fier, that got me interested in Mundorf silver/oil.

 Oh, one thing that I remembered about my other "wooden" chassis. When it had the wooden top, it sounded a little smoother and richer if I listened past the buzz of course. And I believe that it could be used successfully with the heater mod, for another Bijou build 

 And now for something completely different........if you do remove NFB, don't use that extra pot as a light dimmer for the amp. Consider something like L/R volume control. I'm enjoying that capability on my amp, as some recordings don't always seem balanced for volume L/R.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_On E-bay, there is a seller called maxwellaudio. They had listed 1uF Mundorf supreme silver/oil 1200vdc, but the description read .47uF. When I pointed that out, they offered me free shipping. That was just enough of a push, so........those will get here in about 9-10 days. Break-in on those is about 200-250 hours. Edit: the obligatos were actually rated half a point better by another Head-fier. So you will be a happy camper Pabbi. This will give us a wide area for reviews though since many of us have gone in a different direction. The auricaps, obligatos, mundorf, audyn, ft-3 etc...although the real interesting reviews are going to be between balanced build and uber audyn film cap build. _

 

Yes, that review led me in that direction - it was a close call against some Jensen copper foil, but the shipping was too extreme. Gonna fire it up tomorrow, as I've been pinned down on something else. This is the scary part. Anyone else have 'first power anxiety'?


----------



## runeight

In my case it happens everytime I hear that someone else is going to power up one of my designs for the first time. You'd think I'd get over it, but I haven't so far.


----------



## amphead

As long as it's fused Pabbi, the only thing to watch out for is the mosfet/regulators. The fuse will take care of the rest. Edit: you could do a continuity check from the body of the mosfet to the heatsink pin, before you fire it up and that should read "open" of course.


----------



## regal

I learned that the best cure for "power up anxiety" is to check for shorts. Especially check all the power rails to ground, should be open (high resistance.) If you know there aren't shorts you have a high chance of not frying anything, I also don't like to use slo-blow fuses on first power up.


----------



## amphead

That's true, as long as the power supply doesn't see low resistance at the output terminals, or a short, damage to the amplifier is much less likely.


----------



## GeWa

Me received some tubes today! 
	

	
	
		
		

		
			




 20x 6N1P and 8x 6N6P.






 Still a long way of a finished amp though.

 Regards


----------



## G-man

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_Me received some tubes today! 
	

	
	
		
		

		
		
	


	



 20x 6N1P and 8x 6N6P.



 Still a long way of a finished amp though.

 Regards_

 

thats a lot of tubes.


----------



## GeWa

Quote:


 thats a lot of tubes. 
 

I agree, but there's nothing wrong to have some extra. 
	

	
	
		
		

		
		
	


	



 Also they weren't all that expensive.

 Regards


----------



## amphead

Nice to see that you are moving along GeWa. Yeah the tubes can be bought in bulk at a reasonable price. I'm working on my backlit logo/badge, while waiting for my bypass caps.


----------



## fordgtlover

^

 What caps did you decide on amphead? And, for what positions?


----------



## amphead

Well, the bypass caps that I have purchased came from E-bay. 2 Mundorf supreme silver/oil caps at 1uF. Should be arriving in about 8 more days. The seller is maxwellaudio, who has a 100% feedback, and gave me free shipping, which spurred me on to take the plunge. $49.97USD each.


----------



## fordgtlover

I currently have some K40 PIOs that I'm using (nice sound). I bought some Obbligatos (?) to try as well - in both 1uf and 0.1uf.


----------



## chobint

hey guys,
 Just got the boards put together and am trying to work on some unique enclosure ideas. Is there any reason that would prohibit mounting the boards sideways rather than upright? heat issues or stress on the joints perhaps?

 edit: pics! I mounted it using the plates I bought from parts express (262-044) and a pcb standoff kit from radio shack, the holes are not perfectly aligned with the boards but using screws smaller than the pcb holes remedies the problem. I have multiples of these plates and was hoping to put them together using threaded rod and nuts for a minimalist sort of design, but it would require the boards to lay sideways b/c the design is unstable standing tallways.


----------



## runeight

There should be no problem putting everything horizontal. The tubes are all designed to operate properly in a horizontal position.


----------



## Mazuki

Tubes even work upside down!


----------



## regal

The power supply board should be horizontal due to the heatsink.


----------



## amphead

The Mundorf silver/oil 1uF caps came today. Much faster than expected. I am in the process of installing those. What's the sound going to be like, without burn-in? I'll try to describe that soon.
 Edit: congrats Chobint......looking good!


----------



## chobint

ya i was kind of concerned about heat issues regal. Altho I did plan on mounting it with the following configuration so that the heat from the sinks wouldn't rise into eachother.


----------



## amphead

Now that I have the Mundorf bypass caps in, here is the perceived difference from the Wimas. The Wimas have just a hint of grain and sometimes the detail was not as musical as it could be. The Mundorf, have more detail with a laid back musical presentation and more depth, soundstage. The attack on aggresive notes is round, pleasing. If I were to compare it to food, the Wimas are toast, and the Mundorf are toast with butter and plum jam. There's a plummy air to the music. It does color the music slightly, but with K701, the sweetening is enjoyable. I'll finish burning these in and then maybe some WBT rca clones.


----------



## fordgtlover

^

 Amphead, I found the WIMAs very grainy on the output of the Millett Max. I've got some 0.1uf caps on their way to replace the the WIMAs in my Bijou as well. But because of their location in the Bijou, I'm not sure if they cause graininess here too. I haven't noticed any, but maybe I will notice achange when I swap them out.


----------



## chobint

Finally got it fully hooked up last night. I listened to this old recording of a thunderstorm I had and it sounded pretty good with no NFB using my stock akg 701's. Then I turned up the NFB to about 10-15 percent and I could almost feel the water droplets splashing off the ground next to me, it seemed to add so much depth to the sound...but once the pounding of the rain stopped I noticed a clearly audible hum. There is very little to no hum with no NFB, and the static gets progressively louder to the point of overbearing at 50% or higher. I think that my wiring config might be suspect due to the way the level of static changes when the wires are poked and shifted slightly...are there perhaps any wiring taboos i should know about like dont twist the ground with the signal wires, or something of the sort..? forgive my noobdom, this is my first precision audio project. In the meantime I suppose I'll be retracing amphead's hunt for hum through the last 30 pages : )


----------



## runeight

chobint, first thing to do is to make sure the feedback is going in the right direction.

 maximim feedback is when the pot is turned to its minimum value. minimum feedback is when the pot is at its maximum value. i'm wondering if you're thinking of it the other way around.

 if you're having this level of hum there is probably an error somewhere in the wiring. amphead's hum/buzz was barely audible. yours seems to be deafening.

 so, can you post some pictures?

 the main thing is to twist the heater wires together (by themselves) and keep them close to the chassis as much as possible. keep the signal wires away from the heater wires. make sure that everything is solidly connected to the star ground.

 amphead's mod is a very simple one. you won't have to read the last million posts. you can find it on the Bijou website. I guess anything can happen but i am suspecting that the current hum problem won't be solved with this mod. there is something else going on..


----------



## chobint

Thanks rune. I agree I think the wiring is suspect. Wires are twisted but not separated the way they should be. I'll be doing some major tidying up after I discharge it this evening and finalize the casing. I'd gladly post up some pics once it's looking more presentable.

 Also, at minimum NFB the amp is quiet enough that static is not noticeable over the sound of my central AC thru the ducts. The volume is also the lowest at minimum NFB. As NFB increases, the volume increases and the hum gets much louder. I really think rewiring will do wonders, but ill post up a pic or a drawing of my NFB wiring tonight.


----------



## runeight

we'll look forward to the pics.

 on the nfb, we want to be sure that you get the maximum benefit from using it.

 when you turn the NFB pot in the direction where the volume DECREASES this is INCREASING NFB.

 when you turn the NFB pot in the direction where the volume INCREASES this is DECREASING NFB.

 When you run high Z headphones (like senns) you want little or no NFB. when you run low Z headphones (like grados) you may want more NFB.

 So, in your case the hum is worst when the NFB is minimum and best when it's maximum. This is consistent with other builds.

 It is no surprise that the amp sounds better when you reduce the NFB (which is what you've been doing when you thought you were increasing it)


----------



## amphead

As Runeight says, you are thinking in reverse of the actual NFB function. When you get rid of the hum by turning the pot counterclockwise, you also might lose detail, which is why I used Runeights mod to remove NFB. That's up to you, depending on what your ears tell you. Removing NFB, will make any noise present, stay there. Therefore in my case, I did what is described on Runeights web site, which changes the grounding scheme. If you do remove NFB and use the heater grounding mod, you are very likely to end up with a quiet amplifier providing you don't have something else done incorrectly. Good luck! Edit: I'm considering trying NFB again, now that my system is quiet. I wouldn't be using very much, even with K701. This is just to see if my memory of how it sounded was right.


----------



## amphead

With the extremely quiet amp configuration that I now have, I'm going to risk opening up the top plate with some ventilation holes. She does get warm after extended 6 hour listening sessions.


----------



## chobint

Oh silly me, thanks for clearing that up.

 About the wiring. Your post and the site mention keeping the heater wires close to the chassis. I assume that since the chassis is grounded that it helps dampen the buzz from the AC current? If thats true could one use grounded insulated shielding as an alternative? I ask because my case is not conventionally set up...hope to have preliminary pics posted tonight

 Also, I was using an extra terminal block for the grounding wires...did that NEED to be connected to the chassis as well, for reasons like damping the heater wires and/or protecting from outside emf? Reason I intended not to ground the chassis is because I figured having all the ground points fully insulated would reduce the inherrently dangerous shock risk with tube amps


----------



## runeight

It's always best to run AC heater wiring along the chassis, but if you don't have a situation where you can do that, shielding will work pretty well.

 You can also do without shielding just using twisted pairs of wires for the heaters. In this case you have to keep the heater runs away from all the other wiring and when they do cross, try to cross them at 90d angles so you don't have a heater run and a signal/B+ run in parallel.

 Despite the high voltages it is better to attach the amp's star ground to the chassis or you will almost certainly get hum and noise. MHO is also that it's best to ground the chassis to the power ground either directly or through a gorund loop breaker. Don't leave the amp ungrounded and floating.


----------



## amphead

Big, Big update! If you remove NFB and/or use the heater mod, because I'm not sure which is the largest contributor to this effect, be careful of using small walkman mp3 devices. Here's what happened. Before both of those mods my Tascam CD player and Walkman mp3 player sounded about the same through the Bijou. Now something incredible has occurred! The CD player sounds extremely rich and full, while the walkman sounds weak in comparison! And I had not been using the CD player, for several months. With this configuration, the Bijou needs to be driven!  I have been getting tingling up and down my spine, with this new rich sound! Be careful, because due to some input impedance issues you won't know what the Bijou is really capable of. Deepest Bass, thunderous, fullest sound ever with all the detail you will ever need! Forget about plummy sound with those Mundorf bybass caps. It kicks you in the groin. This machine is ready for its debut!

[size=x-large]It is a mind blowing sound machine! [/size]


----------



## regal

I have spent many hours redesigning my DAC since building the Bijou, it is very revealing but scales incredibly well to a higher quality source.


----------



## runeight

Gentlemen, I truly appreciate these posts!!

 amphead, I'm pretty sure that the better sound is a result of break-in and the NFB change. I don't think that the heater mods have affected the audio, except to remove the really annoying buzz.

 The NFB change, however, really does affect the bandwidth and speed of the amp. I knew that some folks would prefer this which is why I included it as a mod from the beginning. Removing the 10k grid stopper from the gain stage is what makes the most difference here.

 What you are hearing, as regal noted, is how well a really good headphone amp will reveal the quality of the source. And if the source is a really good one, then the combination will reveal the quality of the recording. This puts the listening experience into another category altogether. At least IMHO it does.

 Now if we can just get a few more folks to build one . . . 
	

	
	
		
		

		
		
	


	




 Edit: I also think that you should try the NFB again. Now that the other problems are settled, you might find that NFB has some nice effects when you apply just a little of it.


----------



## rfsam

runeight, I've just noticed that most of the Bijou DIY discussion is happening here and not at headwize.com 
	

	
	
		
		

		
		
	


	




 I have a question about this 300 Ohm resistor that I need to put instead of 10k for R1 if I go with no-NFB mode. Can I just solder 309 or 310 Ohm resistor on top of the 10k (in parallel)? That should be equivalent to 300 Ohm. I guess that should work?

 Another question is why 300 Ohm instead of 10k makes a difference if the input impedance of the grid is very high and the input capacitance (grid-cathode) is very low (a few pF)? Just trying to refresh my university tube amp design classes in my memory (that was long time ago and I never had a chance of working with vacuum tubes after that)


----------



## runeight

Yes, no problem putting 300R in parallel with the 10k. Grid stoppers are generally form 100R to 300R. I use 300R as a matter of habit.

 In the Bijou, however, the 10k is required to make the NFB work properly.

 If the stopper resistor saw just the GK capacitance, all would be well. But there is a phenomenon known as Miller Capacitance (see Wikipedia). This is a virtual capacitance that exists in any system with gain. In this case, the Miller capacitance is between the grid and the plate. Its value depends on the gain of the tube itself, but it will be in the many pfs range.

 So, what we really have is a grid resistor in series with a capacitor between the grid and the plate. This RC network reduces the gain of the amp along a curve the falls off as the frequency gets higher. The larger the the R and C, the lower the transition frequency. So, 10k reduces the high frequency gain of the amp and lowers its bandwidth.


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_But there is a phenomenon known as Miller Capacitance (see Wikipedia)._

 

Runeight, thank you! Seems like I forgot more than I thought 
	

	
	
		
		

		
			





 Runeight, is it OK to use wire wound resistors in the plate circuit? Like this one: resistor

 I'm just trying to find the right R3 for Regal Mode - 30k, 2W, 1%


----------



## runeight

I think it's better to use a metal oxide resistor such as the Xicon 283-30k-RC.


----------



## regal

I used this from Digikey: PPC30KW-2CT-ND.


 Also I wanted to report that with the EZ81 rectifier there is no problem running 6N6P's and the 5mA 6DJ8's. I measured 278V input to the regulator.

 It is surprising that a $5 russian tube sounds better than a $20 JJ, but I have seen others report similiar results.

 If I could add another diode under the string on the cathode of the output tubes I could probably switch to 5687's. This would push the bias to 3V which would pull 30 mA @125V. I have no experience with 5687's. I wonder how they would sound 

 ?


----------



## runeight

No surprise on the EZ81. Glad you tried it out. The amp is getting more muscular all the time. 
	

	
	
		
		

		
		
	


	




 I don't think that 5687s have the same pinouts as the ECC99. So you can't directly sub them. However, my guess is that the 6n6P is doing a better job anyway.

 I visited Batman during one of my long trips. I brought the Bijou and we compared it to 5687 WCF ampifiers that I had also designed. The 5687 amps weren't even close. We both heard this instantly without any critical listening at all. The Bijou was just plain better.


----------



## Mazuki

The extra height/volume of the 6N6P over the 5687 has to be good for something eh?


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I think it's better to use a metal oxide resistor_

 

Runeight, yes I suspected that wire wound resistor will have more internal inductance (equivalent serial connection to resistance) that may effect the frequency response of the amp as this R+L is being AC-grounded at the top meaning that from the AC point of view it's connected in parallel to the first stage output and phase splitter input. I.e. normally R3 works as a first stage load. Please correct me if I'm wrong.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Xicon 283-30k-RC._

 

But this one is 5% and not 1%. I was also thinking about three 10k Ohm 1W 1% resistors connected serially and forming some kind of Arc or gate on the board (with leads shorted to minimum).

 Generally, is there ant type/brand of resistors you prefer the most? Metal Film, metal oxide or etc.? Vishay/Xicon/KOA or others from Mouser or Digikey? Or maybe some kind of audiophile grade resistors?


----------



## runeight

Yes, I was thinking of the inductance. The inductance will be very, very small. Much smaller than something that would effect the bandwidth of this amp. But, my general operating procedure is don't introduce a potential problem, as unlikely as it is, if you don't have to.

 I think that 5% are ok for this resistor. The voltage in the first triode doesn't matter that much. 95-105V is ok.

 I tend to think that any good quality resistor is good enough in almost all circumstances. I agree with Bruce Rozenblit that 90% of the amp is in the design. Maybe more. But I know that others feel differently and very strongly about it. So, I always just tell people to try things and see if they like what they hear. Fortunately for us these components are generally really cheap to swap in and out.


----------



## rfsam

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I used this from Digikey: PPC30KW-2CT-ND.


 Also I wanted to report that with the EZ81 rectifier there is no problem running 6N6P's and the 5mA 6DJ8's. I measured 278V input to the regulator.

 It is surprising that a $5 russian tube sounds better than a $20 JJ, but I have seen others report similiar results.

 If I could add another diode under the string on the cathode of the output tubes I could probably switch to 5687's. This would push the bias to 3V which would pull 30 mA @125V. I have no experience with 5687's. I wonder how they would sound 

 ?_

 

Regal, thank you. I just bought two jj/Tesla ECC99. Right now I have 6n6p-s. I'll try swapping them.


----------



## rfsam

Could anybody please recommend me a place where to get a volume pot knob? I need something wide and long as Blue Alps has quite a long shaft. Something made from aluminum similar to what amperehead used in his design? I tried to search a few online stores and ebay but couldn’t find much. Right now I have small plastic knob that doesn't look pretty


----------



## JamesL

Quote:


  Originally Posted by *rfsam* /img/forum/go_quote.gif 
_Could anybody please recommend me a place where to get a volume pot knob? I need something wide and long as Blue Alps has quite a long shaft. Something made from aluminum similar to what amperehead used in his design? I tried to search a few online stores and ebay but couldn’t find much. Right now I have small plastic knob that doesn't look pretty _

 

Partspipe from ebay has a nice selection. Also, you can trim off the shaft with a saw or dremel.


----------



## runeight

Quote:


  Originally Posted by *Mazuki* /img/forum/go_quote.gif 
_The extra height/volume of the 6N6P over the 5687 has to be good for something eh?_

 

Yes, exactly.


----------



## amphead

Quote:


 *Originally Posted by Mazuki*: The extra height/volume of the 6N6P over the 5687 has to be good for something eh? 
 

That's good news.  No major changes for me.


----------



## rfsam

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_Partspipe from ebay has a nice selection. Also, you can trim off the shaft with a saw or dremel._

 

JamesL, thank you! Their selection is really great!


----------



## koike

sry found the answer by looking at the cad diagrams.


----------



## pabbi1

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I learned that the best cure for "power up anxiety" is to check for shorts. Especially check all the power rails to ground, should be open (high resistance.) If you know there aren't shorts you have a high chance of not frying anything, I also don't like to use slo-blow fuses on first power up._

 

Where exactly are the best locations for testing this?

  Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_As long as it's fused Pabbi, the only thing to watch out for is the mosfet/regulators. The fuse will take care of the rest. Edit: you could do a continuity check from the body of the mosfet to the heatsink pin, before you fire it up and that should read "open" of course._

 

Can this be done from the top of the board since I've already bolted everything down?


 Ok, the time has come - tonight is the night. And...

 So, I bend the 100k, >2w resistor, and put it in the VOut and Ground, tightening both, and attaching the voltmeter to each lead.

 1) Do I also have the ground attached to the star ground point on the case?

 2) Should the trimmer control be pre-set to all the way L, R, or pseudo centered?

 3) Any preferred instrument to dial in the voltage? Just worried about dropping the jewelers screwdriver against something in the board - (neuropathy in the fingers just sucks). Yes, one hand only. Rubber soled shoes. No jewelry.

 4) Will the resistor / volt meter drain the caps, given enough time, or do the three points (VOut, R7, R8) all need to be drained seperately, and, using a 50k resistor, how long does that take?


----------



## runeight

1. I recommend that you attach the star ground to the case.

 2. Set the trimmer to its halfway position

 3. Well, if you really have concern that you might drop it you should use a plastic screwdriver or some other plastic instrument. I use jewelers screwdrivers for this and so far I've been ok with them. I put the trimmer near the edge of the PS board so you don't have to snake the screwdrive between a whole lot of components.

 4. The resistor will drain the caps in reasonable period of time. But you should use the voltmeter to be sure.


----------



## pabbi1

Thanks, Alex. I stated my question poorly - on the 100k resistor, one side is in the Vout and the other in Star Ground (with meter attached to each side). Do I also attach a Star Ground lead to the case? Sorry to be so anal.


----------



## runeight

Yes, attach the star g on the ps board to the chassis. Very anxious to hear your results.


----------



## amphead

Me too! Pabbi, if you don't have any problems getting a reading of 250vdc across your load resistor, you are almost home free. No need to rush, just take your time. Also it's important to just relax and follow the steps. Just pull the plug out of the wall if anything goes awry.


----------



## pabbi1

20 minutes of 250v on each psu - a little wobble from 250v to 249v, but very stable - no smoke, no popping, no odor. On to the board heaters - tomorrow. I'll wire tonight, but doubt I get all of it done.

 So far, so good.


----------



## funch

I have a couple of questions regarding the regal mod.

 In my current configuration, I have a separate 1A heater tranny driving an 
 EZ80 regulator. I have no problem running steady at 250V. The main tranny is a 270DAX.

 My input tubes are 6H30's. My outputs are 6N6P's, which I'll have to change to ECC99's.

 Will the regal mod work with the 6H30's? Should I change to the EZ81?


----------



## runeight

good news pabbi1. unfortunately, i'm traveling tomorrow. I won't have internet access until tomorrow night.

 funch, you can keep the 6n6ps if you use the ez81. regal has verified this. your heater transformer will be just right for an ez81.

 but to keep the 6h30s in the front end, make all of regal's mods except for R2. Use 1k3 for R2 (instead of the 487R that regal used). This should come very close to 5mA in the front end.

 measure the plate voltage of the first stage. if you are anywhere near 100V that's a good operating point.


----------



## rfsam

This may be useful for DIYers who are fighting with hum or buzz in their Bijou-s. There is an easy way to determine if the source of hum or buzz i internal (PS, heating wiring, ground loops or etc) or external (interference from external EM sources). Without unplugging your headphones switch off the music and adjust the volume (or/and NFB pot) to the level where you start hearing the hum (or buzz). Switch off the power. If the hum or buzz disappears immediately then the source is internal (that was amperehead's case). If you continue hearing hum or buzz that slowly disappears then you have an interference problem (that was my case). Also you may have a combination of internal hum (or buzz) and EM interference. In this case when you switch the power off the hum (or buzz) level immediately decreases but does not disappear completely and continues to go away slowly.

 I'm not sure if that method will work with other designs but it works with Bijou as the PS keeps high voltage at least a few seconds (much longer in my case) after the power is switched off and the heaters are still hot.

 Sorry if you already know that but I just thoght that it might be worth mentioning.


----------



## amphead

Yeah, that sounds like a reasonable approach. Thanks for your input.

 That's great Pabbi! Just follow the steps on the Bijou website. We will be here, if you need us!


----------



## rfsam

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Yeah, that sounds like a reasonable approach. Thanks for your input._

 

 Amphead, I'm sorry for mispeliing your name hear.
	

	
	
		
		

		
		
	


	




 Did you try putting the NFB back? How does it sound compared to no-NFB mode?

 I just received a set of JJ tubes (e88c and ecc99) and will try them today. Regal's mode is the next.


----------



## amphead

Hey, no worries. I will be trying with NFB, however I have to push that mod out a ways. thanks Edit: I am restructuring/upgrading my "engineering" workbench, going to take awhile.


----------



## koike

Mock up to ensure everything fits before wiring.

 *screwed up the previous case T_T


----------



## rfsam

Quote:


  Originally Posted by *rfsam* /img/forum/go_quote.gif 
_Amphead, I'm sorry for mispeliing your name hear.
	

	
	
		
		

		
		
	


	




 Did you try putting the NFB back? How does it sound compared to no-NFB mode?

 I just received a set of JJ tubes (e88c and ecc99) and will try them today. Regal's mode is the next._

 

Just installed e88c and ecc99 instead of JAN Philips 6922 and 6n6p. Didn't perform A to B comparison yet as it's too soon. I've got about 30 hours on previous tube set and 3-4 hours on the new one. The strangest thing is that ecc99 draws more current than 6n6p. But I guess it's just burning in.


----------



## pabbi1

I have heaters on all amp boards, and almost all signal wire connected. Back to grounding...

 Ok, so attenuator G -> +IStarG -> -IStarG -> Star chasis; then power block +StarG -> -StarG -> Star chasis for each side (L & R) 

 or 

 can each side be all tied together like attenuator G -> +IStarG -> -IStarG -> +StarG -> -StarG -> Star chasis (L & R)? 

 I know the former was recommended, but does this really make a difference? It would be even better if I could just link all the power StarG together, as they all 4 face one another, then a single lead to the chasis ground. Pics later this evening.


----------



## runeight

You know, it may not make that much difference, but my preference is still the first configuration. This establishes a solid 0VDC point among all of the pieces.


----------



## funch

runeight - At the bottom of the 'wiring and ground' page on your website,
 are the 'Clockwise' and 'Counterclockwise' labels for the NFB pot reversed, or am I reading it wrong?


----------



## runeight

Why yes they are backwards. How did that get by for so long!!!

 Thanks for finding it.


----------



## funch

Your welcome.
	

	
	
		
		

		
		
	


	




 I'm replacing the NFB pot. The old one had a weird 'catch' in it, and the channel balance was way off ( 236k vs 252K).

 I thought I'd just double check on the website to make sure I had hooked it up right.


----------



## koike

Hi guys!
 Its 6AM here and wow...im kicking back in my seat burnt out but enjoying the fruits of my labour.
 here is the end result! sorry for the crappy pics as usual.
 initial power up




 internal wiring




 front view





 thank you alex 
	

	
	
		
		

		
		
	


	




 *theres a slight hum but thats for tomorrow...im going to bed after adjusting B+ to 250v.


----------



## koike

Im unable to get 250VDC...any idea guys? 
	

	
	
		
		

		
		
	


	



 Im getting about 238VDC from the ps output terminals.


----------



## runeight

Koike, is the amp working? If so, that's great. Glad everything is stable.

 Are you using 6N6Ps?? If so, please measure the voltage at R7. You may need to use an EZ81 rectifier.


----------



## koike

hi alex!
 its working! im enjoying it at the moment but i cant get it to reach 250vdc.
 im using JJ ECC99s. with E88CC and the EZ80


----------



## runeight

Terrific. Another Bijou comes alive!!

 First, you can run a 238V as long as nothing is burning up.

 But we have to do some detective work. Can you measure the voltages at both R7 and R8 on the leads that are sticking up from the PS board.

 One builder had a bad EZ80 that was not providing a high enough voltage into the first filter cap.

 Let's see what we can figure out.


----------



## koike

R7 is at 242.3VDC
 R8 is at 277.6VDC

 at this time im listening to bjork's so broken.
 im amazed at the detail. D:


----------



## chobint

hah so thats why i wired my nfb backwards! i thought i had followed the diagram correctly. anyway internet was out the day before i left for vacation hence the delay, heres the pics:













 high(er) res:
pic1 pic2 pic3

 wiring is nearly completed, just need to remove and drill out the front and rear plates to mount the jacks and cut off the excess rod. still contemlating how and/or if i'll need to cover it with a cage or something. btw any idea what type of fuse ill need? I'll be buying iec jack /w 10 amp fuse from parts express?


----------



## runeight

The voltages say that the current draw from the amp is very reasonable, around 54mA.

 But the voltage at R8 is about 30V too low. So, a few more things to try.

 Just to be absolutely sure, what is the voltage of the HV secondary and what is the heater voltage? Please check that your HV secondary is wired into the terminal block correctly.

 If both of these check out ok and if the amp is all properly grounded (and all the components are the right values) then the ez80 is not working properly. it may need to break in for a while or it may have to be replaced. generally, when the voltages are this low break in won't really help.


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_hah so thats why i wired my nfb backwards! i thought i had followed the diagram correctly._

 






 Yes, chobint, I've been telling everyone one thing but showing the wrong thing on the website. I kept wondering why everyone was getting this backwards!!!!!
	

	
	
		
		

		
		
	


	




 Looking very nice. That's a pretty cool way to build an amplifier.


----------



## amphead

Congrats Koike! That's great to hear that you have successfully built the Bijou. Enjoy the sound! 

 Good to see that you are progressing on schedule Pabbi!

 Very interesting design Chobint! You wouldn't want exposed High Voltage, so an enclosure is necessary.


----------



## pabbi1

Ok, everything wired up, and I get the faintest of hum... but, alas, the faintest of output as well. It does increase with turning the pot, but to barely audible at midpoint, and a little better at fully open. 

 Measurements:

 VIn - 247v
 R2 - spec 3v, actual 2.2v (all pretty close)
 V1A - spec 100v, actual 94v
 V1B - spec 199v, actual 188v
 R6 - spec 103v, actual 98v
 D4 - spec 2.2v, actual 2.07v
 D1 - spec 127.2v, actual 124v
 V2A - spec 125v, actual 119v

 Couldn't reach the 51v tp except on one board, and it was 47v. Oh, and my led does NOT light.

 So, everything is running a little lower using EZ81, 6n1p and 6n6p. 

 Pics:
Pic1
Pic2

 Even with lower voltages, shouldn't I get more output? Certainly this type faux pas should sound like I have a very basic error.


----------



## runeight

Well, my first thought is that the input signals are not out of phase.

 But, do you have a way to look at the output of each amp independently?? Can you feed a single ended signal into each amp?

 Are all of the heaters lit? The LED comes off the heater run on the input tube. Maybe you have the diode backwards?


----------



## dBel84

pabbi , I would hate to be the harbinger of bad news but one of those power supply caps looks nasty - bulging and ready to go any second ( I am sure it is not just the photo ) , bizzarre that all the voltages check out tough? ..dB

 edit - added pic of cap in mind







 meant to say that it looks pretty darn good otherwise


----------



## pabbi1

Well, all the heaters are lit, but I'll check all the diodes again... the picture is a bit blurry, especially on the right side, but I don't see any bulging on the sides, and the tops are all absolutely flat. It is pretty wild of a thought - maybe another round of pics tomorrow.

 Other than the LED not being lit, nothing else was obvious. Does this sound like a grounding issue?

 <sigh>


----------



## runeight

It doesn't sound like a grounding issue at the moment.

 I think that the best way to proceed is to verify that each amp board works properly. If you can do this, then we can be pretty sure that the problem lies in the inter-board wiring.


----------



## amphead

I enhanced the image in pic1 and there is a cap in the upper right, that looks like the top is bulging, when not enchanced. It is an illusion produced by the photo. So don't worry about the big power supply caps.


----------



## koike

I measured the HV and heaters.
 From left(CT) to right.

 Loaded with music.
 0VAC
 250VAC
 ~3VAC
 ~3VAC
 250VAC

 Everything sounds alright. Bass is full, I'm guessing the current is doing fine.
 Is the drastic voltage drop across R8 critical?
 Will it affect anything?


----------



## amphead

Good eye on that capacitor! I looked in the wrong place. Yeah, that will spray hot/warm liquid all over the place, with a pop. I'm sure Pabbi has removed it by now. Did you have a replacement? Round of applause for dB......that saved you days of clean-up of the nasty liquid on your boards. Edit: it's the reason why some builders prefer to sit behind a sheet of plexiglass on first power-up. As runeight said, treat each side of the amp as a single-ended and get them working separately first if you have problems.


----------



## runeight

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_I measured the HV and heaters.
 From left(CT) to right.

 Loaded with music.
 0VAC
 250VAC
 ~3VAC
 ~3VAC
 250VAC

 Everything sounds alright. Bass is full, I'm guessing the current is doing fine.
 Is the drastic voltage drop across R8 critical?
 Will it affect anything?_

 


 koike, what transformer are you using? The HV secondary is too low. It should be at least 260VAC. If you are using the Hammond, perhaps the primary is not wired properly?


----------



## GeWa

Since we're talking transformers here, can I but in with a question for a moment? For us Europeans who have 230V mains I'm a correct to wire my primary's in series like in the attached image.






 Regards


----------



## dBel84

Gewa , you have it wired up for 220V operation which should work out fine. The HV might be on the higher side as I am pretty sure your line voltage is somewhere between 230 -250 but your region may have better regulation than other areas. I would probably check the line voltage ; if it is 220V then leave it as is, if it is higher then move the jumper up one in the middle to connect the brown and black ..dB


----------



## GeWa

Quote:


 Gewa , you have it wired up for 220V operation which should work out fine. 
 

No, I have not? I'm using the first primary fully, 120 - 0 and the second between 110 - 0. If I add those two together isn't it 230 than?

 Regards


----------



## dBel84

yes, of course you are right. making brekkie for the kids and responding to HF does not a good combination make ;D ..dB


----------



## pabbi1

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_pabbi , I would hate to be the harbinger of bad news but one of those power supply caps looks nasty - bulging and ready to go any second ( I am sure it is not just the photo ) , bizzarre that all the voltages check out tough? ..dB

 meant to say that it looks pretty darn good otherwise _

 

Thank you for the catch! With power off, they aren't bulging, but I do have replacements, Panasonic 47 uF, 450v 105c. 

 The real issue is that just replacing them won't solve the issue, so I still have a root cause to be addressed? I'll post pics of the ps boards as I get there.

 Here is a pic of the caps prior to ANY power - just bad from the get go?

 And, I always at least wear safety classes on power up...


----------



## koike

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_koike, what transformer are you using? The HV secondary is too low. It should be at least 260VAC. If you are using the Hammond, perhaps the primary is not wired properly?_

 

I have checked the HV secondary without load. it is 260VAC
 Once it the tubes are on its about 250VAC.
 I am using custom transformers hand wound by a long time transformer maker.


----------



## amphead

Pabbi, if those capacitors were bulging before you powered it up, I would replace them with caps that are perfectly flat on top. Then power-up keeping a safe distance or using a sheild, piece of plywood, plexiglass etc., then let it run for 15 mins. Power down and see if anything is better of worse.

 Runeight has your back Koike.


----------



## runeight

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_I have checked the HV secondary without load. it is 260VAC
 Once it the tubes are on its about 250VAC.
 I am using custom transformers hand wound by a long time transformer maker._

 

Well, that's going to present some difficulties. What is the current rating on the secondary?

 If the current rating is large enough then your only alternative will be to use an ez81 for the rectifier.


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Thank you for the catch! With power off, they aren't bulging, but I do have replacements, Panasonic 47 uF, 450v 105c. 

 The real issue is that just replacing them won't solve the issue, so I still have a root cause to be addressed? I'll post pics of the ps boards as I get there.

 Here is a pic of the caps prior to ANY power - just bad from the get go?

 And, I always at least wear safety classes on power up... _

 

It's hard for me to tell what the deformity of the top of the can means. However, better safe than sorry. I am assuming that the voltage on those caps is below 450V because you're using a 260-0-260 transformer.

 Replacing the caps will ensure that your PS doesn't blow up, but it still doesn't solve the audio issue. I guess one thing at a time.


----------



## pabbi1

Yes, I pulled / replaced one, but even as funky as it looks in pics, it was still dead flat (no bulge). Replaced with a 47uF 450v Panasonic (same lead spacing, but a little smaller footprint - will replace the other tomorrow- just wanted to see if there was any immediate impact). I also noted I had L & R inverted on pins 2 & 3 at the Neutriks - switched that as well.

 Checked all diodes (OK, assuming the board masks are correct), but I didn't run through all the voltage points again. Nothing obvious is jumping out

 Powered up, after about 10 minutes still getting a solid 248v on each side (no rebiasing), and all tube heaters came up nicely. Getting the same result - attenuators work, R & L are equally operational, well, at the barely audible level. Oh, and the hum is definitely there - faint, but enough to notice.

 Whatever I have done, it is remarkably consistent. I have checked the source, headphones and cable as well.


----------



## runeight

pabbi1 do you have a scope available?? 

 I still think the next step is to determine if each amp board is working correctly. Can you figure out a way to do this?

 There are many questions that come to mind, but from afar the only way I can think of to narrow down the possibilities is to first determine that each amp board is actually amplifying.

 The second thing that comes to mind, as I said before, is that the input signals are not out of phase. Can you check this?


----------



## koike

current rating is 90mA.
 i asked the traffo maker to follow the 370DAX specs which is
 260-0-260/90mA 6.3V/3.5A

 edit: im having slight hum and some distortion as well...


----------



## pabbi1

The second is easier to check, at least tonight. My attenuators are these , where each output has it's own ground, which I had tied together, and have going into the GIn on one channel, before tying into the GIn on the second - is that causing an out of phase? Otherwise, I *think* I'm clean from input to pot in/out, then board in/out to the combo jack as far as signal wiring.

 I'll give seperating the attenuator grounds a try next, as I have some work to do to test the amp boards seperately. Since I have the combo jacks wired SE also, I can test each side as SE, but, will take some wiring work for setting up a source.

 No scope, but maybe someone local has one.


----------



## amphead

Pabbi, in the worst case scenario, you will ship me the amplifier boards and I will wire them one at a time into my rig to troubleshoot. Pro bono on the labor of course. I think we can fix it online though. Most important thing to keep in mind is safety. Always check with your meter before laying hands on it. In particular discharge your output caps on the amp boards and across the High Voltage terminals of the power supply boards. Wait 15 mins. after powering down before doing so.


----------



## koike

bought a tesla ez81.
 dropped it in.
 now the output R7 shows about 250 and R8 shows about 289.


----------



## runeight

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_current rating is 90mA.
 i asked the traffo maker to follow the 370DAX specs which is
 260-0-260/90mA 6.3V/3.5A

 edit: im having slight hum and some distortion as well..._

 

OK. It is possible that your transformer guy didn't include proper regulation in the transformer. That is, when the transformer is fully loaded it should have 260-0-260 on secondary (when drawing 90mA). But when it is not loaded the voltage should be higher. You measurements say that the transformer runs at 260-0-260 when it is not loaded and then it pulls down below that when it is loaded. Can you verify this?

 If this is true, then the heater winding will do that too. It will be at 6.3V with no load, but lower than that with a load. Is this also happening?


----------



## runeight

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_bought a tesla ez81.
 dropped it in.
 now the output R7 shows about 250 and R8 shows about 289._

 

This would say that there is still not enough voltage on the secondary of the transformer somewhere. The ez81 has a very low plate resistance and doesn't drop too many volts.


----------



## koike

yep that is correct.
 i am using a ez81 now seems like the voltage is stable at
 ~247VDC (at the 250VDC/Star G terminal)
 ~252VDC (at R7)
 ~288VDC (at R8)

 is this okay?

 or do i have to switch a transformer?


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_In particular discharge your output caps on the amp boards and across the High Voltage terminals of the power supply boards._

 

Best way to do this? Using the voltmeter on the tube socket, at least on amp boards?


----------



## runeight

Well, it just depends on how you feel about it. You only have 5V across the pass mosfet. This is probably enough, but I prefer to have more.

 Alos, you can run 247V with absolutely no problems if you are comfortable.

 But, MHO is (and I certainly don't want to cause any difficulties) that your transformer guy did not make the transformer properly.

 Here's how it should work:

 1. When drawing 90mA from the HV secondary the voltage should be 260-0-260AC.

 2. When drawing 3.5A from the heater secondary the voltage should be 6.3VAC.

 These conditions must be met when both windings are being used at their maximum currents at the same time.

 However, if you don't want to try to get him to make you another one (and he should do it for free), then dial down to about 240V on the B+. That will be good enough.

 Now, what is the heater voltage when everything is on using the EZ81??


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Best way to do this? Using the voltmeter on the tube socket, at least on amp boards?_

 

pabbi1, use a 10k/1W resistor to discharge the caps. But remember if you short out the PS, the mosfets are toast.


----------



## amphead

Pabbi, my output caps on the amplifier boards are installed in a horizontal position, which allows me access from the top of the board to put a 10k resistor across them. I'll look for a place that can be accessed with the output caps mounted vertically. Also, be careful of shorting the output of the PS when it is powered-up, as Runeight said. 
 Edit: You can attach a wire to one end of the 10k resistor and then put a small alligator clip on one end. Make sure you insulate with electrical tape or similar. Then carefully clip onto pin 6 of the output tube and with the other end, hold it onto the output connection/phoenix of the amp board. Make sure you don't touch bare wire while doing this, therefore the reason for insulating. Hold it there for about 15 - 30 seconds.


----------



## koike

Thanks for all the help Alex. I really really appreciate this.
 Im gonna try and get my transformers replaced.
 At the same time I will measure the heater voltages when I get home from work.
 But at this moment the bijou is sounding really really good. Especially after I plugged in the EZ81. Most of the hum is gone and it doesn't distort/clip that much anymore. Love it when I play jazz on it. Superb lifelike imaging. Cant imagine that it should get better if I do change the transformers.

 Edit: My transformer guy is asking what should the unloaded ratings be? Would you have any idea?


----------



## runeight

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_Edit: My transformer guy is asking what should the unloaded ratings be? Would you have any idea?_

 

Doesn't he know?? 
	

	
	
		
		

		
			





 Good transformers have about a 10-15% regulation factor. Let's split the difference and say 13%.

 So, the HV should be 260*1.13 = 294V

 The heater should be 6.3*1.13 = 7.12V

 But, the unloaded ratings are NOT AS IMPORTANT as the loaded ratings. The transformer must supply 260V at 90mA and 6.3V at 3.5A both at the same time. The unloaded ratings above will be good enough. I think this is about what the Hammond transformer does.

 Anyone who has the Hammond, can give us the unloaded secondary ratings?


----------



## koike

I think he doesnt have anything to load the transformers.
 Lets play it safe and get him to do it at this spec.

 HV 300V 105mA
 Heater 10V 5A

 If I over-rate the ratings it should be fine right?

 Edit: Are there other solutions that I can look at? Eg. dropping the resistor value? or upping the cap value?


----------



## runeight

koike, although at first thought this seems like a good idea 
	

	
	
		
		

		
		
	


	




 these values will be too high. Your transformer will not actually run fully loaded and we don't want the voltages to be too high either because then we have to waste too much power in the PS.

 Do you think you could get him to make the specs in my previous post? Both loaded and unloaded?


----------



## koike

Sure I'll get him to make that.
 Btw which of the TwistedPearAudio DACs would you suggest to go with the bijou? Opus or Buffalo?


----------



## runeight

Great, I think that will be a good compromise.

 I am not a super expert on DAC, but there are quite a few guys on this list who are. Perhaps another diyer reading this thread can make recommendation to koike?


----------



## pabbi1

Here is a better amp board shot (without tubes) - all look the same, so hoprfully anything that is wrong is across the board, so to speak. The annoying part is the LED not working - something related to that I can check? Is it integral to the circuit or spurious?

 LED is 3.8v, Lun 60... rled is 561ohm.

Amp boards

 Alex, sorry that this build is a reach for me, especially balanced. Others should not consider my lacking skills as any reflection on the circuit. 
	

	
	
		
		

		
		
	


	




 Edit: Regarding DAC, I have the OPUS with the Millett Max, but the Bijou will be used with the Azur 840c, which has a better DAC / upsampling angorithms. I am looking at a Buffalo upgrade, since it can read SACD / Hybrid layers native where the (older) Wolfson chip does not. That said, I love the OPUS, but love my Azur even more.


----------



## runeight

pabbi1, don't think twice about it. There is no reason that I can think why this won't work. We just have to find the core of the problem.

 The LED is not integral to the circuit. But if the heaters are lit, the LED should be lit too. Are all of the heaters lit?

 Are we going to be able to test each board independently? Or do we need to craft another approach to debugging the problem?

 BTW, what balanced source are you using? What I am trying to determine is, what is reaching the inputs of all four amp boards? We want to know if the signal amplitude is high enough to drive the amps and, since this is a balanced amp, the signals have to be out of phase. Also, since this is not a truly balanced amp, but two single ended amps wired in a balanced mode, the signal has to be ground referenced.


----------



## koike

sorry alex. so the final specs of the transformers will be at 290V/90mA and 7.2V/3.5A? do i need to over rate for the current ratings?


----------



## runeight

No, if the transformer builder builds to these specs, we should be close. Although, since we don't know what the regulation is, we can't be certain. But, we do know that the transformer you have now is not spec'd right.


----------



## willisv

I have a Buffalo Dac on order, I think it's going to sound really nice with my Bijou. I chose the Buffalo over the Opus since it should be cheaper to build (no need for metronome or S/PDIF receiver) and is supposed to sound as good as the Opus.


----------



## rfsam

runeight, after I installed e88c and ecc99 instead of JAN Philips and 6n6p I've got lower heater voltage and lower B+.

 With JAN 6922 + 6n6p + ez80 I was getting about 6.2 VAC on heaters, ~300 VDC on C6, ~260 VDC on C4 and 250 VDC on B+.

 With JJ e88c + jj ecc99 + ez80 I'm getting 6.1 - 6.2 VAC on heaters, ~292VDC on C6, ~252 VDC on C4 and ~245-248 VDC as B+.

 B+ current in both cases is about the same - 55-63 mA. With JJ tubes current seems to be a bit higher than with old tube set. And I was expecting an opposite. I checked the voltages across R3 and R7 and got about 2.7-2.8 mA total through the first stage (seems to be normal). So, the rest of the current goes through ecc99.

 Also ecc99 seems to be drawing more current through it's heater than 6n6p (I rewired it accordingly). Is that possible or I got a defective tube?

 The strange thing is that I'm also measuring lower HV on Hammond DX370 secondary - it's slightly less than 260 VAC with 60 mA B+ current. With an old tube set HV on secondary was 265 VAC or around. What can be the reason for that? The transformer doesn't seem to be overloaded. It's warm but not hot.

 When I tried to swap ez80 for ez81 (I've got a new replacement rectifier instead of previous defective) the heater voltage dropped even more. Sometimes it couldn't reach 6 VAC (ez81 draws more current through it's heater) and B+ is no better as ez81 has higher resistance due to underpowered heater.

 P.S. I measured power line voltage and it's 117 VAC. Transformer is wired for 120VAC. So I guess that power line voltage variation can easily get me HV variation and heaters voltage variation. Unfortunately wiring transformer to 110V on primary instead of 120V can sometimes bring heater voltage ups to 7VAC which is high. So, having DC regulated 6.3 VDC for heaters may be a resenable mod


----------



## chobint

ditto on the DAC...

 Once I get my Bijou up and running smoothly, a DAC will definitely be the next step since I'm currently using a turtle beach amigo as a source ><. I was seriously considering building a scott-nixon usb tube dac but haven't heard much feedback on it, and its a bit on the pricey side... Was also considering the twisted pear stuff, but as always open to suggestions.

 As far as getting my Bijou running smoothly, funny that pabbi's caps were bulging b/c just before I left c7 on the PSU blew up a few minutes after power up. I didn't get a chance to diagnose it b/c I had to pack, so I'll have to double check the wiring and solder joint again once i get back.

 and to pabbi you give all us underqualified DIYers hope lol : )


----------



## koike

i hope we can get something close.
 i wouldnt be able to get him to change the specs again.
 thanks for the feedback on the DACs.
 I think I shall try getting the buffalo.


----------



## amphead

Sorry to hear about your amp Chobint.

 Pabbi, you are running without NFB. What headphones are you using? Edit: I have studied the pic provided and don't see anything obvious. The pic has shadow in some places that makes it difficult to see. More pics with the boards pulled maybe?


----------



## runeight

Quote:


  Originally Posted by *rfsam* /img/forum/go_quote.gif 
_runeight, after I installed e88c and ecc99 instead of JAN Philips and 6n6p I've got lower heater voltage and lower B+.

 With JAN 6922 + 6n6p + ez80 I was getting about 6.2 VAC on heaters, ~300 VDC on C6, ~260 VDC on C4 and 250 VDC on B+.

 With JJ e88c + jj ecc99 + ez80 I'm getting 6.1 - 6.2 VAC on heaters, ~292VDC on C6, ~252 VDC on C4 and ~245-248 VDC as B+.

 B+ current in both cases is about the same - 55-63 mA. With JJ tubes current seems to be a bit higher than with old tube set. And I was expecting an opposite. I checked the voltages across R3 and R7 and got about 2.7-2.8 mA total through the first stage (seems to be normal). So, the rest of the current goes through ecc99.

 Also ecc99 seems to be drawing more current through it's heater than 6n6p (I rewired it accordingly). Is that possible or I got a defective tube?

 The strange thing is that I'm also measuring lower HV on Hammond DX370 secondary - it's slightly less than 260 VAC with 60 mA B+ current. With an old tube set HV on secondary was 265 VAC or around. What can be the reason for that? The transformer doesn't seem to be overloaded. It's warm but not hot.

 When I tried to swap ez80 for ez81 (I've got a new replacement rectifier instead of previous defective) the heater voltage dropped even more. Sometimes it couldn't reach 6 VAC (ez81 draws more current through it's heater) and B+ is no better as ez81 has higher resistance due to underpowered heater.

 P.S. I measured power line voltage and it's 117 VAC. Transformer is wired for 120VAC. So I guess that power line voltage variation can easily get me HV variation and heaters voltage variation. Unfortunately wiring transformer to 110V on primary instead of 120V can sometimes bring heater voltage ups to 7VAC which is high. So, having DC regulated 6.3 VDC for heaters may be a resenable mod _

 

I initially thought about regulating the heaters, but it is hard to get a regulated 6.3VDC from a 6.3VAC winding. Plus, the currents are very high for small regulators, of the order of 3A. The transformer requirements and power dissipation issues get pretty complicated very fast.

 However, even with 117V line you should get decent results. Tubes in the old days encountered all kinds of situations and the heater circuits were all AC and they had to work. 

 What happens if you run wired for 110V with the ez81?

 Edit: Forgot to say that the ECC99 takes more heater current than the 6N6P. About 150mA more per tube. 

 Also there is enough variability in the tubes that for any given ECC99 and 6N6P the ECC99 will draw more plate current. You could just have the statisitcal combination where the ECC99 could be at the high end and the 6N6P at the low end of their conduction ranges. And since the tubes are so similar to start with . . .


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_As far as getting my Bijou running smoothly, funny that pabbi's caps were bulging b/c just before I left c7 on the PSU blew up a few minutes after power up. I didn't get a chance to diagnose it b/c I had to pack, so I'll have to double check the wiring and solder joint again once i get back.

 and to pabbi you give all us underqualified DIYers hope lol : )_

 

Do you guys know what the voltage rating is on the C6 that you're using? There are only a few ways this cap can die:

 1. Voltage rating is not high enough
 2. It's wired backwards
 3. It's defective

 Many builders are using 400V caps here, but I have always preferred 450V caps so that this cap is not running right at the top edge of its voltage rating.


----------



## chobint

hrm...both c6 and c7 are up to spec as per the official bijou website, so it must be either 2 or 3. I'll have to take a closer look when I get back.


----------



## pabbi1

Always leading the charge of the underqualified builders... my build resume is a string of miracles with a LOT of help... 

 My source is a Cambridge Azur 840c.

 I originally thought about using RCA jacks straight out into the boards, but don't have any pots (without disassembling other builds) to limit the signal - guess I could use a 20-30k resistor to mute if going through the phones, or just measure the voltage output?

 The headphones are Senn (usually) HD600 or (occasionally) HD650.

 I'll pull out all the boards tonight for better pics, though thought enough was exposed on each that if something glaring was wrong, it would show, as all are identical. Bottom shots as well. No NFB at all, including no R12.

 Might wiring shots also be helpful? Or, to trace signal through the XLR -> pots -> boards?

 Thanks, guys. This is really a fun hobby most of the time.


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I initially thought about regulating the heaters, but it is hard to get a regulated 6.3VDC from a 6.3VAC winding. Plus, the currents are very high for small regulators, of the order of 3A. The transformer requirements and power dissipation issues get pretty complicated very fast._

 

runeight, I was thinking about external switching PS. I saw some available (if I'm not mistaken) at our local surplus store. Looks like a big laptop PS with 6 or 6.5VDC and 5A rating. Adding some ferrite rings on the DC cord and a few caps in parallel to heaters may decrease the amount of high frequency noise that those things sometimes have. But tis solution is not elegant  At another hand building a classical DC voltage regulator with additional 8-9 VAC transformer may be too complicated.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_However, even with 117V line you should get decent results. Tubes in the old days encountered all kinds of situations and the heater circuits were all AC and they had to work._

 

Yes, did I forget to mention how great the sound is even when the B+ is down to 245-247 VDC? 
	

	
	
		
		

		
		
	


	




 It's just amazing.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_What happens if you run wired for 110V with the ez81?_

 

That's on my list to try. However this morning I checked the heaters and B+ and got 6.3-6.5 VAC and 254 VDC respectively. C6 was at 303-310 VDC. Then I checked power line and it was 121VAC or slightly more.

 I was also thinking about switching transformer to 110V and adding a small serial resistor to primary winding so that the primary has 115V when power line is 120V. That way the heater voltage will not be too high when the power line is 122VAC and too low when the line voltage drops to 117VAC. My calculation shows that ~15R with 3W rating may work OK. What do you think?


----------



## rfsam

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I originally thought about using RCA jacks straight out into the boards, but don't have any pots (without disassembling other builds) to limit the signal - guess I could use a 20-30k resistor to mute if going through the phones, or just measure the voltage output?_

 

Pabbi1, my understanding is that you need a Volume POT or at least some resistor in parallel to the input as the input stage gets its bias that way. But check with runeight.


----------



## runeight

rfsam, i don't really think you'll need a big hunking heater supply for this. Unless, of course, you really want one.

 Try the 110V primary with the EZ81. The will pull more heater current and it may pull the heater voltage down into an acceptable range. It's no problem if the HV secondary is a little high.

 pabbi1 can you supply a wiring diagram for how you wired the inputs to the amps, including attenuators. Thanks.


----------



## amphead

Quote:


 I originally thought about using RCA jacks straight out into the boards, but don't have any pots (without disassembling other builds) to limit the signal - guess I could use a 20-30k resistor to mute if going through the phones, or just measure the voltage output? 
 

Pabbi, if you are waiting on proper attenuators for the build, you could use an ordinary 50k or 100k alpha pot temporarily from ratshack.


----------



## cetoole

Quote:


  Originally Posted by *rfsam* /img/forum/go_quote.gif 
_I was also thinking about switching transformer to 110V and adding a small serial resistor to primary winding so that the primary has 115V when power line is 120V. That way the heater voltage will not be too high when the power line is 122VAC and too low when the line voltage drops to 117VAC. My calculation shows that ~15R with 3W rating may work OK. What do you think?_

 

You could also put a pair of resistors in the 6.3v secondary winding, one on each leg, to help reduce that voltage somewhat if you find the heaters are running too hot when your primary is wired for 110v. It would also soften the heater startup a bit.


----------



## rfsam

Quote:


  Originally Posted by *cetoole* /img/forum/go_quote.gif 
_You could also put a pair of resistors in the 6.3v secondary winding, one on each leg, to help reduce that voltage somewhat if you find the heaters are running too hot when your primary is wired for 110v. It would also soften the heater startup a bit._

 

Cetoole, yes, I was thinking about that two. But it's a bit harder as I'll need to "play" with the resistors values that are in the order of 1/10th of Ohm. Also I'll probably need to reduce the HV secondary voltage too as it may be too high. The resistor in primary winding will take care of both at the same time (I hope). But it's too early to say as I haven't added a Regal's mod yet.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, if you are waiting on proper attenuators for the build, you could use an ordinary 50k or 100k alpha pot temporarily from ratshack._

 


 No, I have the proper attenuators from the build, but I need some cheapies to run RCA out from one of my DVD players to the in on each board.

 My wiring - Sorry I don't have a graphing tool, not even Visio or MindMap:

 Left channel - Top XLR
 Pin 2 -> L Attenuator, wiper 2 (In/Out), front left board (In/Out), top Neutrik pin2.
 Front L board out -> Top T (SE)

 Pin3 -> L attenuator, wiper 1 (In/Out), back left board (In/Out), Top Neutrik pin 3.
 Back L board out -> Top R (SE)

 Pin 1 -> L attenuator G (both channels), Wiper 2 -> front L board (InG) 
 Wiper 1 -> back L board (InG)

 Front L board StarG -> back L StarG -> StarG

 Top Neutrik G -> StarG (SE)

 Right channel - Bottom XLR
 Pin 2 -> R Attenuator, wiper 2 (In/Out), front R board (In/Out), Bottom Neutrik pin2.
 Front R board out -> Bottom T (SE)

 Pin3 -> R attenuator, wiper 1 (In/Out), back R board (In/Out), Bottom Neutrik pin 3.
 Back R board out -> Bottom R (SE)

 Pin 1 -> R attenuator G (both channels), Wiper 2 -> front R board (InG) 
 Wiper 1 -> back R board (InG)

 Front R board StarG -> back R StarG -> StarG

 Bottom Neutrik G -> StarG (SE)


----------



## runeight

Quote:


  Originally Posted by *rfsam* /img/forum/go_quote.gif 
_Cetoole, yes, I was thinking about that two. But it's a bit harder as I'll need to "play" with the resistors values that are in the order of 1/10th of Ohm. Also I'll probably need to reduce the HV secondary voltage too as it may be too high. The resistor in primary winding will take care of both at the same time (I hope). But it's too early to say as I haven't added a Regal's mod yet._

 

rfsam, I don't think your HV will be a problem. It can be a little high and the pass fet will absorb the extra voltage and get a little hotter. If it burns too much power you can increase the size of R7 and R8. But it's not a good idea to put resistors in series with the HV legs. Remember that the HV current is not continuous. It is delivered in high current pulses as the cap charges and discharges. I don't think would be a good solution.

 My guess is that the heater will be close when you use the EZ81. If not, you can try cetoole's suggestion. You don't have to fine tune the heaters. If you run at 6.8V this will be ok. Hot, but ok.


----------



## amphead

Quote:


 No, I have the proper attenuators from the build, but I need some cheapies to run RCA out from one of my DVD players to the in on each board. 
 

If that would be a permanent solution, I would use some noble pots, or possibly just easier to find alps here. http://www.amb.org/shop/


----------



## koike

hey alex, with my current situation is it ok to proceed with regal's mods to run the tubes hotter?


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_rfsam, I don't think your HV will be a problem. It can be a little high and the pass fet will absorb the extra voltage and get a little hotter. If it burns too much power you can increase the size of R7 and R8. But it's not a good idea to put resistors in series with the HV legs. Remember that the HV current is not continuous. It is delivered in high current pulses as the cap charges and discharges. I don't think would be a good solution._

 

Runeight, no, I didn't want to add any serial resistors on HV before the C6 cap. My idea was to add a serial resistor to primary winding of the 370DAX after I set it to 110V. Just between the power switch and the 110V primary. 15R resistor should drop ~5V (from 120VAC down to 115VAC) if I'm not mistaken with my calculations.

 But I'll do all the mods before and see if that's required or not.


----------



## runeight

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_hey alex, with my current situation is it ok to proceed with regal's mods to run the tubes hotter?_

 

Maybe. I think we should wait to see how your new transformer performs. If it has a higher secondary voltage than we really need then regal's mods should work easily.


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_No, I have the proper attenuators from the build, but I need some cheapies to run RCA out from one of my DVD players to the in on each board.

 My wiring - Sorry I don't have a graphing tool, not even Visio or MindMap:

 Left channel - Top XLR
 Pin 2 -> L Attenuator, wiper 2 (In/Out), front left board (In/Out), top Neutrik pin2.
 Front L board out -> Top T (SE)

 Pin3 -> L attenuator, wiper 1 (In/Out), back left board (In/Out), Top Neutrik pin 3.
 Back L board out -> Top R (SE)

 Pin 1 -> L attenuator G (both channels), Wiper 2 -> front L board (InG) 
 Wiper 1 -> back L board (InG)

 Front L board StarG -> back L StarG -> StarG

 Top Neutrik G -> StarG (SE)

 Right channel - Bottom XLR
 Pin 2 -> R Attenuator, wiper 2 (In/Out), front R board (In/Out), Bottom Neutrik pin2.
 Front R board out -> Bottom T (SE)

 Pin3 -> R attenuator, wiper 1 (In/Out), back R board (In/Out), Bottom Neutrik pin 3.
 Back R board out -> Bottom R (SE)

 Pin 1 -> R attenuator G (both channels), Wiper 2 -> front R board (InG) 
 Wiper 1 -> back R board (InG)

 Front R board StarG -> back R StarG -> StarG

 Bottom Neutrik G -> StarG (SE)_

 


 pabbi1, if I read this correctly, it makes sense. The important thing is that the grids of the input tubes are grounded through the attenuators.

 Where are things now? Are we replacing the PS caps?


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_pabbi1, if I read this correctly, it makes sense. The important thing is that the grids of the input tubes are grounded through the attenuators._

 

Can you expand on this a bit? Each attenuator ground is going to Ground In on each board (2 ground points on each attenuator), but I have the ground tied together with the incoming ground from the XLR (a jumper across the two channel grounds. Otherwise, I could run a seperate ground from pin 1 to each ground point on the attenuator. This is a bit fuzzy to me, as to whether it is correct.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Where are things now? Are we replacing the PS caps?_

 


 Well, I tried the other source through each channel with a cheap RS pot - miserable failure, so I was draining the amp boards for (as yet undetermined) further action. I replaced the one PS cap, but the other is holding steady (no bulging, voltage deviation). I will replace it in short order, once I get some traction on the amp boards.


----------



## runeight

First, let's sync up on the wiring. Is your amp wired something like this?

 This is just for one channel. Your grounding at the input may be slightly different.


----------



## pabbi1

Yes - that is good to go - the only real difference is that + StarG -> - StarG -> StarG on both Input and power block. Oh, and no Pin9 as I'm using 6n6p and 6n1p.

 She sounds great - at about one milliwatt...


----------



## runeight

OK. This is a start.

 Can you please measure the voltages at pin 6 of the input tube on all four of the boards.

 I'm assuming that your B+ is somewhere around 250V.

 These four voltages should be around 100V. If they are, we can try the next step.

 Instead of connecting the headphones between pins 2 & 3 of the output jack, can you connect them between 2 & GND and then between 3 & GND? Clip leads will be perfectly alright for this test. This will tell us if each amp is putting out a signal or not.

 If this test gives the same mW output as before then either the boards are not working or the input is messed up somehow. But, at least we'll have narrowed this down a bit.


----------



## pabbi1

Will do - pin voltages _with_ the input tubes in (I know this sounds stupid even as I'm typing, but...)? B+ has been rock solid at 247v. I do know that in draining the amp boards through pin 6, the starting voltage after 15 minutes of power off is 50-56v. 

 Just for reference, I am using 6N1P-VI and 6N6P.

 Sorry to everyone else to watch the Chinese water torture - well, or US water boarding.


----------



## runeight

Also, just to be sure, did you make the cathode resistor (R2) changes as shown on the website for 6n1p?

 Yes, voltages with the tubes in and glowing.


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Also, just to be sure, did you make the cathode resistor (R2) changes as shown on the website for 6n1p?

 Yes, voltages with the tubes in and glowing. 
	

	
	
		
		

		
		
	


	


_

 

Affirmative on R2 at 1.5k. I will recheck this first thing.


----------



## pabbi1

R2 is 1.5k on all boards. The pin 6 voltage on the input tubes is 94-96v. B+ is 249v.


----------



## runeight

Great. This is good news. My guess is that the amps are working. But we have to know for sure.

 Is there a way to apply a single ended signal to each board and then take the output from either pin 2 or 3 of the output jack to ground? All you have to do is feed the output of a portable CD player into the In and In G of each board and take the output from whichever pin on the O/P jack corresponds to that amp.

 BTW, are you using NFB or have you left it out?


----------



## chobint

hey guys, anyone know what rating of fuse I should be using for the bijou(standard U.S. setup /w jeffs kit and 370dax)? thanks


----------



## regal

I think I saw a few questions about a mod to run the 6N1P at 5 ma like I did with the 6DJ8. This really isn't a good configuration for the 6N1P on this amp. At 5 mA and 100V a-k the 6N1P would need less than 0.5V cathode bias. This would lead to clipping in all but the most sensitive headphones.


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Great. This is good news. My guess is that the amps are working. But we have to know for sure.

 Is there a way to apply a single ended signal to each board and then take the output from either pin 2 or 3 of the output jack to ground? All you have to do is feed the output of a portable CD player into the In and In G of each board and take the output from whichever pin on the O/P jack corresponds to that amp.

 BTW, are you using NFB or have you left it out?_

 

NFB was left out. I do hear the faint 60htz hum, though, and will look at the Amphead mod down the road, assuming it doesn't go away. Will try the signal testing tonight.


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_hey guys, anyone know what rating of fuse I should be using for the bijou(standard U.S. setup /w jeffs kit and 370dax)? thanks_

 

IIRC, I used a 1A slo blo in mine. I think this will do for the newer builds too.


----------



## runeight

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I think I saw a few questions about a mod to run the 6N1P at 5 ma like I did with the 6DJ8. This really isn't a good configuration for the 6N1P on this amp. At 5 mA and 100V a-k the 6N1P would need less than 0.5V cathode bias. This would lead to clipping in all but the most sensitive headphones._

 

Right. Will not work. 6N1P is not a direct sub for 6922, although it is often claimed to be. It wants to run at much higher voltage, hence the bias issue here.


----------



## amphead

I have my fingers and toes crossed for good sound from your amp running each side single ended Pabbi. If that works out, then getting it set-up in balanced config. should come soon after.


----------



## pabbi1

Not sure whether to be happy or sad... or neither..

 In checking, all the amps have output to some smaller portable headphones - maybe I need to rerun the tests with the Senns, just to make sure it wasn't just the source driving the phones.

 I decided to pull all the SE (TRS pin) wiring to isolate balanced first (fewer wires for sure), as this is (only) how I intend to use this amp - SE was for meets just for SE only phones. Sod all that.

 The results were mystifying - 

 Left channel: Back board: Pin 2, signal, Pin 3 no signal (output wired to pin 3)
 Front board: Pin 3 signal, Pin 2 signal (output wired to pin 2)
 *** May check this again - non-sensical.

 Right channel: Back board: Pin 2, no, Pin 3, yes (output wired to pin 3 
 Front board: pin 2, yes, Pin 3, no (output wired to pin 2)

 I was very careful to run Pin 2 with white from input to final output, and Pin 3 with red all the way, just to avoid mixing phase.

 No difference.

 Maybe a bad Neutrik? I do have another set to try - tomorrow.


----------



## amphead

I wouldn't think that this is a faulty Neutrik, but wiring is high on the list. The reason for doing single-ended tests, would not be for the final configuration, but it would indicate if on-board components and solder joints for the amplifier boards are working. I realize what a messy thing it is to have wiring for SE and balanced at the same time.


----------



## runeight

I'm inclined to agree with amphead about the jacks.

 Assuming that the nonsensical thing is just a wiring mistake, this test seems to say that all boards are amplifying. Is that correct? If so, do you get a reasonable amount of power from each board? You should be able to drive the headphones to loud levels from each board. Yes? No?


----------



## pabbi1

Yes, I was getting loud levels from each amp, but through some crappier phones. I'll rerun tomorrow through the 650 just to make sure the output is much louder than what I experience through the jacks. I agree on wiring, but I might have another look at the output terminals - could NOT having the NFB or using just a two position connector on the NFB terminal have any effect?


----------



## amphead

No, when NFB is removed, the amplifier will run louder and usually noisier(without heater mod). It does however, have more detail which is why I think that I prefer the amp without it. I will be doing another test to find out later. If you have an unacceptable amount of buzz or hum and your heater wires are tightly twisted, try the heater mod. Edit: My amp sounds very good and the only component change that could improve it, would be better input tubes than the 6DJ8 national "made in USSR". I would want to keep the bias the same and find better input tubes. Trying the 6n6p as input tubes again, produced lower volume overall, some distortion on loud vocals/horns etc. , they are definitely suited for output tubes only.


----------



## chobint

woot home at last. So I've almost got my amp dead quiet. I replaced my blown up C7, grounded the case, nfb/volume pots....and moved my amp away from my surge strip which was the reason for the deafening buzz lol. So now I've hooked up my magic wand (long grounded piece of aluminum) which I waved around the case and wiring to diagnose areas of high EMF interference. As expected the input/output wires which are still uncased since I havent drilled the front plate yet, got quieter when I waved the wand over them. So I expect once those wires are inside the case that will be solved.

 BUT...heres the wierd part. As is, the buzz level is noticeable but relatively quiet at full volume with minimum nfb, and becomes hardly noticeable somewhere between 3/4 and 7/8 volume with minimum nfb. BUT...when both pots are grounded and I touch the one of their casings it gets DEAD QUIET. If the pot that I'm touching is ungrounded it gets loud and buzzy, but if its grounded its dead quiet. So...my amp is dead quiet if I sit there and hold one of the pots in my hand lol. Also it was near dead quiet with a dry finger, completely quiet with a wet finger touching it. Any idea what would cause this and/or how to make the effect permanent w/o me touching it all the time.

 edit: i only have to touch one to make the setup quiet...doesn't seem to matter which one.


----------



## funch

You keep poking a wet finger around in a tube amp, and you'll be 
 running dead quiet too. 
	

	
	
		
		

		
			





 (Sorry, couldn't resist).


----------



## chobint

lol ya i know, but the other hand was insulated and like i said the input/output wires are outside of the casing away from the boards/power cords.


----------



## pabbi1

Amp boards are all fine - quite good (outrageous) output from each into the Senns.

 When plugged in via the jacks, with the (100k) attenuators 100% open (99k ohms) it sounds good, albeit faint. No hum. Fully closed is 0k, so the attenuators *seem* to be working, as they do respond in getting louder (relatively speaking) as they are turned up and lower when down.

 Sadly, I need to check the Azur (source) again, though I don't have any other (functioning) balanced amps available. In reading Tangent';s troubleshooting from long ago, should I be able to check input signal with a voltmeter?

 Back to ground (once again)... the inside of the Nabu is clear annodized - IEC and star are screwed into some standing metal offsets that are tack welded to the sheetmetal - all the stars are touching one another via soldered eyelets, very snugly via the screw pressure. BUTT, I did not grind down to bare metal on the case (through the annodize) - worthwhile?

 Again, thanks for your patience.


----------



## runeight

chobint, that's really good news. The peculiar finger grounding feature might go away what you get everything enclosed. 
	

	
	
		
		

		
		
	


	




 pabbi1, what happens if you connect the balanced source but take the SE outputs from pins 2 & 3 on the O/P as in the SE test. Do you get signal from the amp boards?


----------



## pabbi1

No, it sounds like pass through signal from the source. Same as through the XLR balanced.


----------



## runeight

so the amps put out a nice healthy signal when fed SE and loaded SE.

 but they put out the weak signal when fed balanced but loaded SE?

 If so, this means that either the balanced signal is not big enough to drive the amp (hard to believe) or the balanced signal is not ground referenced.

 the attenuators should handle the ground referencing. but maybe they are not.

 we need to be able to measure the amplitude of the signal at the amp inputs with respect to ground when running in balanced mode. do you have a way to do that?


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_so the amps put out a nice healthy signal when fed SE and loaded SE.

 but they put out the weak signal when fed balanced but loaded SE?

 If so, this means that either the balanced signal is not big enough to drive the amp (hard to believe) or the balanced signal is not ground referenced.

 the attenuators should handle the ground referencing. but maybe they are not._

 

Completely agree. Since these are stereo attenuators , I _tried_ to do this by running the input ground to one channel, tying it to the other, then running seperate input grounds to each amp board. I also tried untying the channels to see if one channel would work - not so much.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_we need to be able to measure the amplitude of the signal at the amp inputs with respect to ground when running in balanced mode. do you have a way to do that?_

 

No, at least not that I am aware. No scope nor access to one that I've found.


----------



## pabbi1

Ok, fixed, and fauxed. I doubled back and added a second lead from Pin 1 to the attenuator giving seperate leads to each ground rather than tying together. Amp boards now passing signal!

 BUT, in messing with a solder bridge on one attenuator, I managed to mangle one smd resistor beyond repair (thought it was just extra solder gobbing things up - Darwin award candidate), and pulled the other out of contact, generating a rather loud and obnoxious buzz on the damaged side. New attenuator incoming, but, it will be a week. I'll be positive and _hope_ the buzz is all from the damaged attenuator.

 NO chance at all I can repair the attenuator, as SMD is just beyond my physical capabilities. I can wait for the new one.


----------



## runeight

Good news! and Bad news 
	

	
	
		
		

		
			





 So, are both channels now working in balanced mode? You just have to wait for a new attenuator?


----------



## pabbi1

Kinda undetermined on the right (with buggered attenuator), but the left is just fine (unbuggered). With the buggery, other than the UGLY hum, not sure what I get there, but I want to think I was getting signal also under the hum. Since I was worried about phone damage, I didn't visit too long, nor desired a revisit.

 Pretty confident we now know the answer, but don't yet know what the exact status is, especially if I'll still have at least a little hum issue.

 Now, to hunt down an icon vendor for a plate while waiting...


----------



## amphead

Pabbi, if you have a 50k or 100k volume pot laying around, you could use it to see what is going on before the stepped attenuator arrives.


----------



## pabbi1

I have some real crappy fake ALPS stepped, but would have to harvest one from another build. It still wouldn't answer the hum issue completely, and being stepped it would most likely not match steps with the other. But, the performance of amp boards would be fully put to bed. 

 Ok, talked me in to it. 

 Besides, I'm thinking this might be worthy of Goldpoints anyway.


----------



## rfsam

I've just made some modifications to my Bijou.

 I removed the NFB pot and changed R1 to 300R. Basically I just soldered 300R on top of the 10k. I left R12 intact. Now on maximum volume level I can hear hum (or buzz or both) that's coming from internal AC (interference on input that goes away when I short input to ground.). But that's on the levels that probably will just burn my HD580 and damage my hearing. On normal hearing levels it's as quiet as before. I guess the GAIN went up when I disconnected the NFB and now I can hear AC wiring interference on the inputs.

 Runeight what is the maximum GAIN with NFB (POT set to 250k -> min NFB) and when NFB is disabled?

 Also it seems like grounding the RCA jacks helps with this hum at maximum volume. But I need to verify that.

 I've also switched 370DAX transformer down to 110V and added two 32R 2W paralleled resistors (i.e. 16R, 4W equivalently) serially to the primary winding. Now when I have 117VAC on power line my transformer is at 110V exactly providing 306-310 VDC on C6 (with EZ81) and ~6.2 VAC on heaters. But the resistors are getting quite hot and I'll have to change them for something that has 6-10W total power rating. I'll probably have to use 14-15R resistor if I go with Regal mode as the voltage on C6 will drop below 300VDC when both stages start drawing another 14 mA of current.


----------



## chobint

Just powered my Bijou back up after fully casing it, and WOW~!@ so quiet. Turned off every device in my room and the blood flowing thru my ears was all I could hear for a good 5 min. It's funny how they say silence is deafening, b/c it really is quite loud. And no it wasn't just really loud static lol 8). pics in the next few days hopefully

 It really is amazing how dramatic music can be when the sound floor is so low. When the background music drops out and the track goes accapella it's like going over a dip in the road where your stomach drops a little bit.

 Feelin pretty good considering my 300 n' change amp sounds just as good as an old roomies $1200+ SS amp. Thanks Rune for sharing your amazing design with us.

 Edit: rfsam, I wrapped two grounded wires around my input wires to help minimize any AC interference. I don't have my NFB modded like you do, but my amp is completely silent at max vol with my heater wires less than 6 inches from my input wires. Oh ya, and have you checked to see if your high-voltage and low-voltage ground wires are away from eachother? That was causing a bit of hum for me too I believe, until i rewired it.


----------



## rfsam

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Edit: rfsam, I wrapped two grounded wires around my input wires to help minimize any AC interference. I don't have my NFB modded like you do, but my amp is completely silent at max vol with my heater wires less than 6 inches from my input wires. Oh ya, and have you checked to see if your high-voltage and low-voltage ground wires are away from eachother? That was causing a bit of hum for me too I believe, until i rewired it._

 

Chobint, thank you for the comment! Do you have your NFB enabled (wired)? When I had it enabled my amp was quiet too (with the cover on). The gain was not enough to get this hum (buzz) to audible level. Now (with no NFB wired) I can hear a hum. And when I have the source plugged in (e-mu 0404 USB) the only hum I can here is coming from an outside EM interference and not internal wiring. I can here internal wiring too when the input is not loaded with source (floating). So, I guess there is no problem with internal wiring or ground loops. I use shielded cables from the inputdown to Volume POT and from Volume POT to the boards. I'll try to use better ones (I have a few feet of microphone cable). Will try to do Regal's mode in the next few days, fine-tune the PS and after that I'll be done with tuning


----------



## chobint

Edit: So what you just said above just sunk in for some reason...before I fully enclosed my components in my case, the amp was noisiest floating\completely disconnected, slightly quieter hooked into open ended rca's, and even quieter when hooked up to a source.

 If your problem is anything like mine, I would recommend making a grounded metal wand and waving it around your casing and in between wiring paths while listening at full volume for changes in buzz. I don't know what others would say about the safety of this method, but personally it was immensely helpful in allowing me to eliminate my buzz. If you were to try it you would obviously want to thoroughly insulate the wand before using it. I would also recommend tapping the wand on the amp enclosure, and the nfb and volume pot casings. I would also see if touching your finger to the rca jack yields any reduction in low freq noise, both while the amp is floating and while connected to a source. You would obviously not want to be touching any other part of the amp while poking the RCA jack since you are technically touching a ground. And is the shielding around your input wires connected to the star ground?

 And yes my NFB is hooked up, so your gain is probably higher than mine. However, your effective R1 is ~291ohms which would yield an even higher gain than the recommended 300 (i might have my logic backwards). I think I may drop by Radio Shack on the way home from work and grab a few resistors to try the amp w/o NFB.


----------



## rfsam

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_And is the shielding around your input wires connected to the star ground?_

 

I'm using a regular (single ended) shielded cable, not the balanced one. In this configuration it's not supposed to be grounded directly to star ground or chassis. It's connected to "In G". I may try to ground it directly to starG or chassis but in this case I have a chance of dealing with ground loop problem. I was also thinking about putting a second isolated shield over the main cable shield and connecting it to ground. But the thing is that this hum is not bothering me too much as I can just destroy my ears and my Senns at this volume level  On a regular listening level it's not audible.

  Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_And yes my NFB is hooked up, so your gain is probably higher than mine. However, your effective R1 is ~291ohms which would yield an even higher gain than the recommended 300 (i might have my logic backwards). I think I may drop by Radio Shack on the way home from work and grab a few resistors to try the amp w/o NFB._

 

R1 should not drive the gain as it's much lower than input impedance. At least not 301R versus 291R.

 You may still have this hum. It's just not audible when you have NFB. My amp was virtually quiet when I was using NFB. It's really not that big of a deal.  Amphead had much bigger problem as his Hum was not just interference.

 Thank you for the wand idea.


----------



## runeight

Hello gents. Sorry, I have been away for a bit. I'm not sure I'll get to all of the questions in the last handful of posts.

 rfsam the gain with 250k on the nfb pot is about 12X. With NFB disabled gain is about 25X.

 With no NFB the value of R1 won't change the gain.

 Is appears as though you guys are getting good results, but there is some residual hum.

 rfsam, i guess you can't get away with no resistors on your transformer even with the EZ81? How much does the heater voltage increase when you remove the resistors completely?

 chobint i'm waiting for your pictures. 
	

	
	
		
		

		
		
	


	




 Edit: A really good way to do the grounding for shielded cable is like this:

 1. Connect the inner wire as normal
 2. Connect the shield to ground at only one end. Trim the other end.
 3. Run a separate wire for the actual ground connection

 So, for the input jack to pot, run the inner wire, connect the shield to the star ground, and then run a separate wire from the input jack ground to the pot. 

 This technique keeps ground currents out of the shield. Do this for all of the shielded cable.


----------



## chobint

my apologies, i was mistaken with R1. And wow I had no idea disabling nfb doubled the gain, theres a good chance that hum would be audible on my amp as well. I want to try creating a circuit that enables and disables nfb with the simple flick of a switch. I think it would be relatively simple by just moving some components to a small square pcb and soldering wires to the boards...but I'm slightly concerned that by increasing the path length it may introduce more interference? is that something to be concerned with? Anyway i doodled up a schematic but ill have to host it when i get home


----------



## runeight

You can try this, but you are correct. Any noise you generate by putting more wires or a switch in the NFB circuit goes right into the grid of the input tube.


----------



## chobint

well poo. I can see, however, how eliminating the NFB circuit could help cut down on noise, atleast the way I wired it. With the pot mounted to the case and wires running to it, rather than the pot close to the board and a long rod extending the nob.


----------



## runeight

But, if you want a small amout of NFB without the pot, then you can just put a 220k resistor across the NFB terminals on the board. This will substitute a fixed resistor for the pot and all the associated wires and still reduce your gain. If you think that's too much NFB then try 270k or 330k or even 430k or 470k.


----------



## chobint

Hrm...interesting. I do enjoy playing with the NFB nob still, but...I think once I find the sweet spot I may run my multimeter across my favorite setting and substitute a permanent resistor for it. While I am curious as to how it sounds w/o nfb...I do think the amp sounds better at 25% nfb with my k701s. Also curious...what would happen if you simply disconnected the nfb pot wires and left the resistors as is?


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_rfsam the gain with 250k on the nfb pot is about 12X. With NFB disabled gain is about 25X._

 

 Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_rfsam, i guess you can't get away with no resistors on your transformer even with the EZ81? How much does the heater voltage increase when you remove the resistors completely?_

 

I was playing a bit with 370DAX set to 110V on primary. With no resistor and 120V heater voltage goes up to 7VAC and sometimes above. When the line voltage drops (probably to 117VAC, but I didn't measured it by that time) heaters are at 6.7-6.8VAC. I guess 6.7-6.8VAC is OK but 7VAC or more is higher than normal? Another thing is HV being too high when not using resistors. I think it will be high even when I implement Regal's mode. But I'll try and let you know. I rewired the primary in the way that it's very easy to play with resistors. I'll send more pictures later on.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_chobint i'm waiting for your pictures. 
	

	
	
		
		

		
			



_

 

Me too 

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Edit: A really good way to do the grounding for shielded cable is like this:

 1. Connect the inner wire as normal
 2. Connect the shield to ground at only one end. Trim the other end.
 3. Run a separate wire for the actual ground connection

 So, for the input jack to pot, run the inner wire, connect the shield to the star ground, and then run a separate wire from the input jack ground to the pot. 

 This technique keeps ground currents out of the shield. Do this for all of the shielded cable._

 

Runeight, thank you. I'll try that as well. This hum is not bothering me but just to make things completely perfect  Please check 01.jpg that I attached. Is that what you just described? Will it make any difference which side of the shield I choose for star G connection? I.e. I can choose to connect to Star G near RCA jacks and Amp. board IN and not near Volume POT.

 Also, will it be better if I use a balanced shielded cable (like a microphone cable with 2 central wires - we have it in a local store)? I drew it in 02.jpg (attached)?


----------



## chobint

Originally pic 2 is what I had imagined, but after reading it again pic 1 looks correct, I will of course let runeight tell us which one is correct. If pic1 does in fact show the proper configuration...would it be better for me to wire my RCA interconnects like that when I construct them soon?

 Oh jeez, crazy ideas beginning to fly thru my head. I could make an dual RCA to dual 1/4 headphone jack interconnect, hooking up the RCA signal and ground to the L and R pins respectively, and the shielding to the ground pin (star ground). Or I could make a dual RCA to triple RCA cord which would ground each shield to a third RCA jack connected to the star ground. The second of the two would be more compatible should I ever wish to use the cords with another amp but the first would be totally wicked and custom lol...

 Edit:Ya sry pics tonight as long as I don't pass out at 7pm like yesterday : P. Still deciding if I want to trim the rods or not.


----------



## runeight

Pic 1 is what I do and it seems to work pretty well. It's what I was trying to describe.


----------



## amphead

Good job guys! 
 Well, I think I'll try NFB with a fixed resistor, probably about 15%. It has to wait a few days.


----------



## chobint

Pics! 
	

	
	
		
		

		
		
	


	























 Hi-res:
front
top angle
back angle
back
top
side

 So I'm pretty satisfied with it for my first self-enclosed build, but will probably go back and tune up a few things. As you can see I botched the back plate and scratched up the front plate so that will definitely be redone. Would like to go back and make the wiring more perty since its so open. Theres still a little bit of tension in the rods, so once the case starts sitting flatter I'll prob toque em back down and cut off the ends.

 EDIT!: AHAH...so I found another low level buzz and nipped it in the bud! I just remembered this one pair of sony earbuds I own is like 2x louder than all my other cheap headphones, and 4x than my k701s. So i popped em in and found a buzz due to a faulty ground wire. Funny thing was that the buzz increased with MORE NFB, so I said to myself hrmm...the output line must have something really dirty running thru it. Sure enough, the headphone ground wire appears to be internally microfractured and in need of replacement.


----------



## runeight

I really like your construction. Are you going to wrap something around it?

 As you can see, HV tube amps are a bit more sensitive to grounding schemes and other EM issues. But, once these are addressed, the amps can have a really nice, easy on the ear sound.


----------



## chobint

UPDATE: Ok so I was totally wrong about my noise problem, but to answer Rune's question first... I should wrap something around it but that would kind of kill the aesthetic. Better than the aesthetic killing me I suppose. Honestly though, I want to enclose it, but I've yet to think of a way that would add to the look rather than detract, so its a WIP.

 ok so UPDATE...I was completely wrong about the faulty wiring. I'm not sure what's going on atm so I'll explain it. Right now I have a low pitch buzz, that is medium loud at Max NFB, and quiet at Min NFB. The buzz does NOT vary when the volume pot is twisted. The following are the combinations of wires hooked up and the how the buzz level reacts
 **I have three ground jumpers, one running from starG outside the case, one running from starG inside the case and one running directly from the RCA ground jack**
 1)Inside starG only OR Outside starG only (i.e. how it would normally be wired) = medium
 2) Inside starG + Outside starG = medium-low
 3) Inside starG + Outside starG + RCA ground = low
 4) RCA ground ONLY = very quiet, seems damn near dead quiet but too loud in my house to tell.
 None of these grounding schemes seem to affect the tone or sound of the music from the source.
 **I'm not sure how to put this, but if I were to hook up an odd number of ground wires it is loud, but if I hook up an even number of wires it gets quiet. I didn't list all the combinations I tested, but as you can see the ones I list all follow suit except for grounding to the input channel**


 So strangely, wiring the output ground through the input ground gives great results, but that is a very strange grounding scheme. And to add to the mess there is a different higher pitched audible static sound when the NFB is turned to Min, this also does not react to changes in the volume pot.

 Also, when I plug in my RCA jacks, in the split second that my tip is in but the ring has yet to connect it makes a very loud buzzing noise in the channel that's being plugged in, is that normal?


----------



## amphead

Just to double check, NFB decreases as you turn the pot clockwise and this is where you hear the loudest buzz.


----------



## chobint

Yes that is correct. Fully clockwise, or Min NFB, yields the most EMF static. However, my unorthodox buzzing problem, which is solved by grounding the output thru the input ground, gets louder with Max NFB, or fully counter-clockwise.


----------



## amphead

My input rca grounds and output ground from the output jack both go straight to star ground. I think this is the best way to avoid a ground loop. Edit: but then again, I have the ground mod which totally eliminated noise for all positions of the volume pot.


----------



## chobint

Hrm...ya my rca jacks as well as my volume pot are grounded to the inG terminal. I guess I'm wondering is it safe to ground the output jack thru the inG terminal? because that yields excellent results

 Gonna pick up some dayton audio 1u 250v caps to try in place of C6 this weekend 
	

	
	
		
		

		
		
	


	




. Too bad the audiocap tin 1u were only 200v : \


----------



## runeight

chobint, I think for your build, you should use whatever the heck works for the grounding scheme.

 A star ground works best when you have all components enclosed in a nice chassis and the ground runs are reasonably short.

 But, your build is open and long. Your wiring distances are much longer than normal for all of your runs. These long wires provides lots of opportunity to pick up ambient EM and for wires to crosstalk noise to each other.

 I think that one thing that will help is to have a wrap around shield around the decking to keep the EM out. 

 The other major effort will be to find a grounding scheme and a wiring placement scheme that eliminates the hum. You may also want to try amphead's heater mod. It may or may not make a difference, but it's worth the effort if all else fails.

 Also, try the fixed NFB resistor. It may still work better.


----------



## runeight

rfsam, I've lost track of where you are. Is your build working properly now?


----------



## Ferrari

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Pics! 
	

	
	
		
		

		
		
	


	



 ...
 Hi-res:
front
top angle
back angle
back
top
side
 ..._

 


 Very unusual 
	

	
	
		
		

		
		
	


	



 ...but I like the "out of the box" way of thinking!


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_rfsam, I've lost track of where you are. Is your build working properly now?_

 

Yes, everything works fine. But I want to try changing resistors values on amp boards to implement Regal's mode. Then I'll see if PS needs any tweaking. And finally I'll try this input cable wiring that you mentioned to eliminate hum completely. But my Bijou currently works great, thank you! 

 Recently I purchased e-mu 0404 and must say that it's internal SS headphone amp is not that bad either. 0404 may be just a perfect match for somebody who wants an inexpensive all-in-one solution. But Bijou's sound is more pleasant (smoother) when connected to e-mu's line-out.


----------



## amphead

The next Bijou that I build is going to use pillars and floors/levels for the chassis similar to yours Chobint. I can think of a couple of ideas for running wiring inside the pillars, using them as conduit/shielding. The amp would be oriented so that the legs are on the bottom. Square channel aluminum 2 inch, copper pipe 2 inch etc. Bottom floor transformer, second floor power supply board, 3rd floor amplifier boards L/R. Heater wires running up two legs from bottom floor to 2nd floor and third floor. Separating ez80 heater wires from amp board heater wires. Signal wiring running up/down the other two legs. Top of the amp/roof small rotating beacon.  I might even create it as a prize to be won by some lucky Head-fier! Similar to what was done for the Beta22. Imagine the excitement, when our fellow Head-fiers realize that they might be struck by lightning too! 

 Edit: btw, keep source volume lower and amp volume higher for a little better resolution and less distortion. When running my source at mid volume and the amp compensating at lower volume I lose some fidelity and get a tinge of distortion on loudly recorded vocals or similar sound. Really enjoying high quality recorded material with the amp in this mode, taking on the load. It shouldn't provide more headroom, but it seems too. Runeight? Or maybe the source was overdriving the preamp.


----------



## chobint

Cool, I like your idea amphead. Sounds similar to the original, super-clean, mostly no-wire look I had imagined, but lacked the skills to make. I think you may find, even with only three layers, that the amp will be quite tall and will need a very wide base to remain stable.
  Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I lose some fidelity and get a tinge of distortion on loudly recorded vocals or similar sound_

 

I've been getting a fair bit of this with loud midrange vocals too, the sound is vibrant but choppy. It's audible at all amp volumes, but the source volume is fixed since it's a cheapo dvd player.

 Edit: deleted previously posted question


----------



## runeight

Quote:


  Originally Posted by *amphead* 
_Edit: btw, keep source volume lower and amp volume higher for a little better resolution and less distortion. When running my source at mid volume and the amp compensating at lower volume I lose some fidelity and get a tinge of distortion on loudly recorded vocals or similar sound. Really enjoying high quality recorded material with the amp in this mode, taking on the load. It shouldn't provide more headroom, but it seems too. Runeight? Or maybe the source was overdriving the preamp._

 

You _can _over drive the input. So there is balance to be struck between source volume and Bijou volume. However, to get the best fidelity I think you want to come out of the source from line outputs.

 You both may be hearing distortion in the source and you may not have heard it before. The Bijou is pretty good at revealing the quality of the source, either the electronics or the recording itself.


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_rfsam, I've lost track of where you are. Is your build working properly now?_

 

Runeight, I did Regal's mode yesterday and got some problems with an input stage at one channel.

 I have a pair of new JJ e88c that replaced JAN Philips 6922 at the front.

 With Regal mode I see 4.3 or 4.7 mA through the first stage of one channel and 5.8mA through the first stage of second channel. The plate voltages are 115V and 96V respectively. The second stage is also unbalanced as it's bias relies on the plate voltage of the first stage. And I can hear a permanent static (not hum or buzz) on the channel that draws less current at the front (where I have 115V on a plate). This static has a strong hearable level that has no reaction on volume pot. I tried swapping the tubes between channel and the voltages and static follow the tube. Just did that to check if something is wrong with my soldering.

 B+ is at 243VDC, C6 is at 299VDC, heaters are 6.2-6.25 VAC, total current is about 76 mA. So, I definitely need to push 370DAX slightly beyond it's specs.

 I guess one of the JJ e88c is defective? That's strange because they where tested to be pair matched. But maybe they where tested at 1mA and not at 5mA.

 Then I tried to put my old 6922 back. Now I'm getting 88V and 94V on plates with no audible static. But unfortunately one of my 6922 is very sensitive to any vibrations (I can hear that when I slightly tap on the chassis or move the Volume POT). B+, total current and other voltages are pretty much the same as before.

 I thing sound became slightly juicier 

 Now I fully understand what Jeff Rossel meant when he told me that tubes are tricky  They really are!!!


----------



## regal

I would say the tube must be defective, 5 mA's is still pretty low for a 6922, its common to run them at 10 mA.

 What is your voltage at the input of the regulator? Are you using the EZ81?


----------



## runeight

I agree with regal. The tube is not necessarily bad, but it is fairly far away from the norm. You could try letting it break in for a while to see if the emissivity of the cathode increases.

 Tubes are not any trickier than BJTs or MOSFETS. They SEEM to be because they have nice sockets and you can swap them in and out.

 But, nearly every circuit with an active device must be designed for the operating points of those devices. If you swap out active devices the circuit can go whacky.

 You don't notice this much on SS amps because you don't swap out the devices. For example, if you have a mosfet output stage on an amp, you couldn't expect it to work if you swapped out the power mosfets with completely different devices. The reason the mosfets seem trouble free is because they are soldered in to the board and you can't swap them out. 
	

	
	
		
		

		
			





 Your results are pretty reasonable. Try running the transormer on the 110V taps. If you can pull the B+ up to 250V the rest of the voltages will be reasonable.


----------



## dBel84

speaking of swapping out active devices ......







 perhaps for the next project ?? 
	

	
	
		
		

		
		
	


	




 ..dB


----------



## regal

Yes I recently built a Jfet discrete DAC, the first Jfets I used gave a noise very similiar to tube noise, at first I thought it was the 6DJ8's in my Bijou. So yes solid state devices can hbe just as noisey as tubes


----------



## rfsam

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I would say the tube must be defective, 5 mA's is still pretty low for a 6922, its common to run them at 10 mA.

 What is your voltage at the input of the regulator? Are you using the EZ81?_

 

Regal, I'm having about 50V voltage drop across R7+R8, so it's about 250V at the input of the regulator which is low. That's running the primary winding of Hammond 370DAX at nominal voltage. The only solution I see here is to push 370DAX beyond it's rated voltage at the primary. That's why I'm trying to use 110V with some serial resistors with primary winding. I'm getting 117V to 122V on power line.


----------



## runeight

with your new op point have you tried the 110V operation without resistors?


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I agree with regal. The tube is not necessarily bad, but it is fairly far away from the norm. You could try letting it break in for a while to see if the emissivity of the cathode increases._

 

I have ~20 hours on those JJs.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Tubes are not any trickier than BJTs or MOSFETS. They SEEM to be because they have nice sockets and you can swap them in and out._

 

Runeight, I agree with what you're saying, although I see some differences 


  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Your results are pretty reasonable. Try running the transormer on the 110V taps. If you can pull the B+ up to 250V the rest of the voltages will be reasonable._

 

I just tried to connect 110V winding taps directly to powerline (no resistors). I'm getting ~285VAC on loaded HV secondary, ~320-330VDC on C6, ~270VDC on C4, ~250VDC output, ~56V drop across R7+R8, ~6.75VAC on heaters. That's with 118.5VAC on powerline. I guess when powerline will go up to 122VAC I will be getting ~300VDC on HV secondary and ~7VAC or more on heaters. I guess that's high and above specs both for tubes and transformer.


----------



## amphead

Wow, I'm imagining a very warm xformer after a couple hours of use, not to mention some hot resistors. Are you using a separate transformer for heaters? That might be one way of reducing heat on the power tranny.


----------



## runeight

Quote:


  Originally Posted by *rfsam* /img/forum/go_quote.gif 
_I just tried to connect 110V winding taps directly to powerline (no resistors). I'm getting ~285VAC on loaded HV secondary, ~320-330VDC on C6, ~270VDC on C4, ~250VDC output, ~56V drop across R7+R8, ~6.75VAC on heaters. That's with 118.5VAC on powerline. I guess when powerline will go up to 122VAC I will be getting ~300VDC on HV secondary and ~7VAC or more on heaters. I guess that's high and above specs both for tubes and transformer._

 

These numbers are not so bad and if it weren't for the heater voltages, things would run happily at 122VAC on the 110VAC windings.

 An alternative is to go back to 120V operation and simple set the B+ to 240V. I think the amp will sound about the same.

 Another alternative is to run at 110V and put a resistor in series with one of the heater leads. 0R13 would do the trick if you are pulling 3.5A. It will burn about 2W so a 5W resistor would be in order. I've done this myself on a few projects.

 And, of course, there is the resistors in series with the primary. Perhaps this is the best solution.


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_These numbers are not so bad and if it weren't for the heater voltages, things would run happily at 122VAC on the 110VAC windings.

 An alternative is to go back to 120V operation and simple set the B+ to 240V. I think the amp will sound about the same.

 Another alternative is to run at 110V and put a resistor in series with one of the heater leads. 0R13 would do the trick if you are pulling 3.5A. It will burn about 2W so a 5W resistor would be in order. I've done this myself on a few projects.

 And, of course, there is the resistors in series with the primary. Perhaps this is the best solution._

 

Runeight, I have more results 

 I added 12.6R resistor (two paralleled 5W resistors) in series with primary.
 My tube configuration is JAN Philips 6922 + JJ ECC99 + JJ EZ81.
 With 118VAC on powerline I was getting ~112VAC on transformer primary, 265-266VAC on HV secondary, 6.22-6.3VAC on heaters, 299VDC on C6, 251VDC on C4 and ~244VDC on B+. So, heaters are OK but B+ is low. I need more voltage at C6. 

 I could try smaller resistor - 10R or 8R in series with primary but decided to try my old 6n6p instead of ECC99 as my 6n6p-s draw less current both for heaters and plates.

 So, here's what I'm getting at this moment (12.6R in primary circuit):

 117.4 VAC - powerline
 111.7 VAC - primary
 ~269 VAC - secondary HV
 6.31 VAC - heaters
 ~310 VDC - C6
 ~264 VDC - C4
 ~250 VDC - B+

 Everything looks pretty much normal  I guess I still be OK if the powerline will jump to 122VAC.

 Now I'll try to burn in my e88c-s more but I'm skeptical that this static noise will go away.

 The reason I wanted to try serial resistors for the primary instead of serial resistors for heaters is that's it's easier to "play" and connect 10R resistor than 0.2 Ohm one. But I may be mistaken here.

 I'm attaching a few pictures.


----------



## runeight

Pictures look great. I hope that you can finish the casing soon.

 It appears that you have found a decent compromise with the power line resistors and the 6n6p.

 I continue to be surprised at two things: 1) the conduction of the ECC99s and 2) the plate resistance of the EZ81. 

 But, when the current draw starts to creep into the 80mA range then we're out of the spec for the dropping resistors in the filter section. That is, they were originally designed to drop the right voltage for 50-65mA. At 84mA they drop too much voltage for the regulator.

 You could try making R7 and R8 smaller, say 270R each. You probably won't increase the ripple noise, but you might be able to run with 84mA and the ECC99s.

 Still, this seems to be good news.


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Pictures look great. I hope that you can finish the casing soon._

 

Alex, thank you! The casing is finished, I just removed the top cover that also hold the back panel. I'm not sure if my casing is optimal. If I would start from the beginning I probably would go with externally mounted tubes and transformer.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I continue to be surprised at two things: 1) the conduction of the ECC99s and 2) the plate resistance of the EZ81._

 

EZ81 seems to be pretty reasonable - with my ez80 I was getting lower voltage at C6. But from ECC99 I was expecting lower current draw than from 6n6p. Maybe I just need to give ECC99 more time? I remember 6n6p was drawing more current when it was younger  I have about 25 hrs on ECC99 right now (maybe less).

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_But, when the current draw starts to creep into the 80mA range then we're out of the spec for the dropping resistors in the filter section. That is, they were originally designed to drop the right voltage for 50-65mA. At 84mA they drop too much voltage for the regulator._

 

I'm getting ~45 VDC on R7+R8 with 6n6p-s and ~50VDC with ECC99-s. So, it's about 68 mA and 76 mA respectively.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_You could try making R7 and R8 smaller, say 270R each. You probably won't increase the ripple noise, but you might be able to run with 84mA and the ECC99s._

 

Yes, I started thinking about that but wanted to take my chances with serial resistors to primary.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Still, this seems to be good news._

 

Yep, and it sounds great also! Many thanks to you Alex! 

 Maybe I'll try to redo the input wiring with the grounding method you mentioned a few days ago.

 Alex, just wanted to mention that maybe we need larger holes for Plate and Cathode resistors. I had some hard time trying to fit 2W resistor for R3.


----------



## amphead

I'm going to install a set of 47uF 500v Ruby Gold caps across my output caps to take the 410uF to 457uF. I just realized that I had those in my parts bin. Don't know if that will really extend the bass or increase low mids, or just reduce sound quality. Here goes. Edit: yeah thats good news Rfsam, happy to hear that you have built another great sounding amp! I'm really enjoying the sound too, but just another tweak to see if I can get even more.


----------



## amphead

Did it make a positive change? Uh well yes, can I say Orpheus for the cash challenged? Wow! Nice and plump(like a fat grub from the Australian outback, juicy) signature, with plenty of detail. Fat bass and mids just right. Vocals golden, no distortion. I couldn't be happier with the sound now! Edit: I have to say that with the K701's, don't go any lower than 460uF for your total output capacitance. Edit: it cost about $400.00 to build the Bijou in my configuration, but sounds like ten times my investment! Built in an appropriate commercial grade chassis with WBT connectors, it wouldn't be out of place in the nearest high-end Hi-Fi stereo store.


----------



## chobint

Hey amphead, what cap are you using for your output cap (c5)? I am also trying to tweak my amp out for use with k701's


----------



## adamus

Gents, I will build a bijou this year and am just putting in an order for a case (Buying from hifi2000, tagging it on to an order for a dac case. 

 I am looking at this: does it look a suitable size? modushop.biz
 (330 x 280 mm).

 It looks tight but doable. Or should i look for something bigger to give a bit more room for the transformer (is huma big problem? I will mount the tranny ontop, and all tubes will be poking through.


----------



## rfsam

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Did it make a positive change? Uh well yes, can I say Orpheus for the cash challenged? Wow! Nice and plump(like a fat grub from the Australian outback, juicy) signature, with plenty of detail. Fat bass and mids just right. Vocals golden, no distortion. I couldn't be happier with the sound now! Edit: I have to say that with the K701's, don't go any lower than 460uF for your total output capacitance. Edit: it cost about $400.00 to build the Bijou in my configuration, but sounds like ten times my investment! Built in an appropriate commercial grade chassis with WBT connectors, it wouldn't be out of place in the nearest high-end Hi-Fi stereo store._

 


 Amphead, good to hear that!  I think in your case it's not the total value of the output cap that you increased but the total Q of those 3 caps (you have 3 of them in parallel, right?).


----------



## rfsam

sorry


----------



## rfsam

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Edit: yeah thats good news Rfsam, happy to hear that you have built another great sounding amp! I'm really enjoying the sound too, but just another tweak to see if I can get even more._

 

Amphead, thank you  I'll try to reduce the hum by using the grounded wiring scheme proposed by runeight. Maybe I'll just stop after that and just start listening more music  Could you post pictures of these caps?


----------



## amphead

See next post.


----------



## amphead

Here is a link to the 410uF photoflash caps that I used.

RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 180242991066 end time Aug-12-08 08:48:03 PDT)

 Here is a link to the 47uF Ruby Gold caps that I used.
http://cgi.ebay.com/Ruby-Gold-Caps-4...QQcmdZViewItem


----------



## rfsam

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Here is a link to the 410uF photoflash caps that I used.

RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 180242991066 end time Aug-12-08 08:48:03 PDT)

 Here is a link to the 47uF Ruby Gold caps that I used.
Ruby Gold Caps 47 mfd @ 500V axial-style capacitor - eBay (item 350072552867 end time Aug-20-08 10:18:26 PDT)_

 

Amphead, thank you! Why did you select this particular electrolytic cap? Is it good? I'm just trying to decide if I need these for myself  What could you recommend for polypropylene 1uF cap also? I remember there were some recommendations in this thread (from Ferrari?) but don't want to read all 100+ pages again  What do you have for 1uF cap right now?


----------



## amphead

The photoflash was recommended by Mazuki, who was one of the first builders of the Bijou, and it turned out to be a smooth sounding capacitor with plenty of detail. The Ruby Gold was something that I had left over from another build and turned out to be very good.


----------



## amphead

For 1uF bypass caps. I am using the somewhat pricey Mundorf silver/oil. It has a very detailed and smooth signature. Some others that I would recommend are the Obligato, Auricap and Vcap/teflon foil.


----------



## koike

getting my new transformers later.
 will put them in tonight after i get back home from work.


----------



## chobint

So I performed amphead's grounding mod and it did wonders to eliminate half the noise. Also this mod seems to have increased the amps sensitivity to source noise. Placebo effect?? donno but it seemed worth mention. The other half of the noise was from a physically audible, loose tranny case, which was also vibrating noise into my right channel 6922 which gets a bit microphonic at max volume with sensitive headphones(earbuds). While all this noise was only audible(to me) on the earbuds and not my k701's, the changes seem to have helped smooth out the choppiness in loud vibrant mids. go figure

 Next step will be upgrading bypass caps, any opinions on audiocap theta vs auricap?


----------



## amphead

Happy to hear that the ground mod has reduced noise with your amp.


----------



## koike

i apologize in advance for my newbishness.
 which would actually be the bypass caps? what other caps can be replaced with good effect?


----------



## amphead

C6 on the amp board.


----------



## koike

do i have to do anything about c5 since its in parallel with c6?


----------



## Ferrari

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_do i have to do anything about c5 since its in parallel with c6?_

 

To my humble opinion, as long as the electrolytic C5 is in the signal path, it will largely (≥98%) determine/limit the sound quality of the amp, no matter what you use for the bypass cap C6.
 The bypass cap C6 is intended to lower the ESR of the electrolytic C5 a bit.
 Due to (unpredicted) interactions of the 2 caps (C5 and C6), the sound can be (positively or negatively) influenced, but sound wise you won’t win much! 

 If you are using high impedance headphone (≥ 300Ω), you can best replace the electrolytic C5 _entirely_ for a MKP film cap (≥ 100µF). C6 can be a high quality (PIO, Teflon, silver mica…) cap or omitted completely.


----------



## adamus

gents, if i solder all caps etc to the underside of the board, will i get the boards in a 40mm case (tubes poking out) ?


----------



## JamesL

doublepost -


----------



## JamesL

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_gents, if i solder all caps etc to the underside of the board, will i get the boards in a 40mm case (tubes poking out) ?_

 

It depends on the caps you use, but I don't see why not. If the default electrolytes don't fit on the board, you could always just off-board them, or find smaller axial ones.

 This is, of course for the amplifier board.
 The caps used on the PSU are too big, and the heatsink should be mounted on the top.


----------



## adamus

cheers, looks like for simplicity i should use the 80mm case.


----------



## chobint

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I have to say that with the K701's, don't go any lower than 460uF for your total output capacitance._

 

So I purchased those rubycon photocaps off ebay (thanks for the link), and will be running a setup similar to amphead with a 410uf electrolytic, a 1uf bypass cap, and a filler cap to boost my total output capacitance to 460ish. My question is, if you noted a solid increase in SQ going from 410uf to 458uf, is it feasible to believe that the amp stands to gain from increasing the total output capacitance to 470uf, 490uf or 510uf+? (i dont even know if those values are reasonable)

 The reason I ask is because parts express(local) offers ruby gold capacitors in values of 47uf, 70uf, and 100uf. They also offer dayton audio metalyzed capacitors in values of 40uf, 50uf, 60uf, 75uf, 90uf, and 100uf.
 Edit:Is it okay to use a film cap for my second 47uf+ output cap? I always notice people saying don't use film caps with low ohm headphones (k701's here).


----------



## amphead

Film will certainly be better(and large), you can go 47uF or 70uF it will extend very slightly deeper with the latter. I used the caps that I had on hand for that. Edit: one small issue with photoflash caps is that you have to solder on leads to the terminals. And the terminal with knurled top is the negative side.


----------



## chobint

cool, thats what I was hoping to hear. I think I'll compromise between the two at 60uf for a stock 471uf. And of course thanks for the heads up. My potentially fried future caps are very grateful : D


----------



## dBel84

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_gents, if i solder all caps etc to the underside of the board, will i get the boards in a 40mm case (tubes poking out) ?_

 

You need at least 2 inches (50mm) if you want the caps upright. I think 60mm will give you some breathing room for the necessary spacers etc for safely mounting the board underside..dB


----------



## adamus

great, thanks for the advice. I am ordering a few cases from modushop.biz. Its either 40mm or 80.


----------



## koike

hi runeight, pmed you but i think you didnt see it.
 I checked voltages with my new transformers.
 0VAC
 275VAC
 3.7VAC
 3.7VAC
 275VAC

 im able to get 250VDC and R7 has 275VDC R8 has 315VDC.
 im getting 3.2VAC on all heater inputs on amp boards as well.

 edit: should i do regal's mod to run the tubes hotter?


----------



## runeight

Yaaaah!! So the amp is working and you are listening to it?


----------



## chobint

Ok so I guess I forgot the step where I was supposed to take voltage readings AFTER I hooked in my amp boards. Using 370 DAX, EZ80 for the PS, and 6922/6n6p for amp boards. The following are my readings:

 Amp boards hooked up /w pot fully tightened for max voltage(voltages typically fluctuate +-.2v fairly often):
 230.6v +-.3 @ PSU 250v terminal
 265.7v +-.1 @ PSU R8 long lead
 249.1v @ PSU R8 short lead
 233.2v @ PSU R7 long lead
 249.1v @ PSU R7 short lead

 185.7v @ pin1 6922, right board
 88.3v @ pin3 6922, right board
 88.2v @ Pin6 6922, right board
 2.78v @ pin8 6922, right board

 230.1v @ pin1 6n6p, right board
 115.7v @ pin3 6n6p, right board
 113.9v @ pin6 6n6p, right board
 2.078v @ pin8 6n6p, right board

 187.6v @ pin1 6922, left board
 84.5v @ pin3 6922, left board
 84.5v @ Pin6 6922, left board
 3.095v @ pin8 6922, left board

 230.2v @ pin1 6n6p, left board
 119.7v @ pin3 6n6p, left board
 117.6v @ pin6 6n6p, left board
 2.095v @ pin8 6n6p, left board

 PSU only with 100k resistor to ground(voltages typically fluctuate +-.1v very slowly):
 250.0v @ PSU 250v terminal
 354.0v @ PSU R8 long lead
 351.3v@ PSU R8 short lead
 347.8v @ PSU R7 long lead
 350.5v @ PSU R7 short lead

 So I guess this is the problem with using 6n6p's that the EZ81 is supposed to remedy?


----------



## koike

it was working all the while D:
 but its running at the correct voltage now.

 Edit: the hum is still there. not very audible but i can hear it.


----------



## runeight

chobint, it does appear that you'll need the ez81. Your voltages are pretty low even though the voltages say you're only drawing 52mA.

 What is the HV secondary AC voltage?

 koike, that just great. Now you can forget about the transformer and figure out the hum. If it is really a hum you might just have to move the heater wires around. If it is a buzz, you may have to try amphead's mod.


----------



## chobint

Voltages at terminal block where it connects to the xformer, with psu and amp boards connected, (relatively frequent but sporatic +- ~.6% voltage fluctuation):
 .001v
 268v +-1.5v
 3.13v +-.02v
 3.13v +-.02v
 269v +-1.5v

 Some extra info, in case it's pertinent:
 -B+ Voltage does NOT respond to turning the screw on the pot when the amp boards are hooked in. If it does change, it is negligible.
 -My xformer is hooked up as follows: black lead to neutral prong, white to live prong.
 -I have amphead's heater mod installed, two 100ohm 1/2W(5%) resistors ran from each of the the 6.3V terminals respectively on the PSU board to starG. PSU components R9, R10 and C7 removed.
 -My left channel 6922 is considerably more microphonic than the right.
 -The "Saucer", for lack of a better word, or plate over the top of my right channel 6n6p is bent downward toward the topside of the heating element.
 -Being the toob noob that I am, I did not include a heater warm-up switch, which I guess is something you're supposed to do.


----------



## koike

runeight, i already have amphead's mod done. im not using NFB though. i could live with the hum, i can only hear it if there is no music and if its very very quiet. should i run the tubes hotter as well? i have bought the components to do regal's mods.

 edit: recommendations of values for c5 and c6?


----------



## pabbi1

New pot is installed, and, back to the same problem - tiny output. Apparently, the crapped out pot somehow grounded the balanced signal. Alas, wired 'properly' is less than successful.

 Try, try again.


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Voltages at terminal block where it connects to the xformer, with psu and amp boards connected, (relatively frequent but sporatic +- ~.6% voltage fluctuation):
 .001v
 268v +-1.5v
 3.13v +-.02v
 3.13v +-.02v
 269v +-1.5v

 Some extra info, in case it's pertinent:
 -B+ Voltage does NOT respond to turning the screw on the pot when the amp boards are hooked in. If it does change, it is negligible.
 -My xformer is hooked up as follows: black lead to neutral prong, white to live prong.
 -I have amphead's heater mod installed, two 100ohm 1/2W(5%) resistors ran from each of the the 6.3V terminals respectively on the PSU board to starG. PSU components R9, R10 and C7 removed.
 -My left channel 6922 is considerably more microphonic than the right.
 -The "Saucer", for lack of a better word, or plate over the top of my right channel 6n6p is bent downward toward the topside of the heating element.
 -Being the toob noob that I am, I did not include a heater warm-up switch, which I guess is something you're supposed to do._

 

Well your AC secondary voltage is right on target. You should be getting more voltage into the first filter cap (where you measured R8). You should probably try the EZ81, but there may be other issues.

 First, there isn't anything you can do about a microphonic tube except to replace it. They don't generally get better.

 But the main issue is that your B+ does not change with trimpot adjustment. It might not be able to go higher, but it should go lower. This usually means that one or both of the mosfets have been toasted. What happens when the PS is not loaded with the amps. Your 100k resistor voltages are very good, but can you adjust the B+?


----------



## runeight

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_runeight, i already have amphead's mod done. im not using NFB though. i could live with the hum, i can only hear it if there is no music and if its very very quiet. should i run the tubes hotter as well? i have bought the components to do regal's mods.

 edit: recommendations of values for c5 and c6?_

 

This kind of hum is usually a heater wiring problem (wires too close to signal wires or the boards) or a grounding problem. Perhaps you could try moving the heater wires around to see if anything changes. If it does, you might be able to identify the offending wires.


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_New pot is installed, and, back to the same problem - tiny output. Apparently, the crapped out pot somehow grounded the balanced signal. Alas, wired 'properly' is less than successful.

 Try, try again._

 

Well that sucks. 
	

	
	
		
		

		
			





 I don't know that we can make any more progress without being able to put a scope on the inputs of the amp boards. We know that they all amplify when fed an SE signal. We have to know what signals are getting to the inputs in balanced mode and how they are ground referenced.

 amphead are you still around?


----------



## dBel84

just a thought.....could this not be a phase issue? The amps work in SE but seem to have very little output balanced. If signals were out of phase then they would be canceling each other? or not so. 

 ..dB


----------



## amphead

Yeah, I'm here! Definitely seems Pabbi's losing signal to ground somehow. Pics?


----------



## runeight

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_just a thought.....could this not be a phase issue? The amps work in SE but seem to have very little output balanced. If signals were out of phase then they would be canceling each other? or not so. 

 ..dB_

 

Yes, it could be a phase issue. This is why I'd like to get a scope on the input signals at the boards.

 There are two things that have to be right at the input:

 1. Signals must be 180d out of phase.
 2. Signals have to be referenced to ground.

 The second item is because the individual amps are ground referenced and they must see a ground referenced signal to work. This means that each phase of the balanced signal has to have amplitude with respect to ground.

  Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Yeah, I'm here! Definitely seems Pabbi's losing signal to ground somehow. Pics?_

 

pics will help. amphead, some number of posts back you said the pabbi1 might be able to send the full amp to you. Is this still a possibility? Do you have a scope available? We might be getting close to this transaction if we can't diagnose from the pictures.


----------



## amphead

Yes, Pabbi can send me the amp and I will put it on a scope. First I would see if it is a source issue by using my source, even though that's probably not it. I would just look at the amplitude of the signal from input/first triode stage/second triode stage......to output stage.


----------



## chobint

Yes, unloaded the B+ is fully adjustable. With the trimpot fully tightened from my previous attempts to achieve 250v loaded, my unloaded B+ voltage was at 278v which I promptly turned down to 250v. 
 **Again, something possibly relevant...B+ voltage hits a maximum, both loaded and unloaded, just after power up. After that peak, the voltage will slowly decline until it eventually settles on a median value. Unloaded the B+ is rock solid at 250v once it settles, seldom fluctuating only +-.1v. Loaded the B+ voltage will usually wander +-.3v, then every so often will wander up/down a few volts, and rinse and repeat.
 Edit:Sorry to hear pabbi : (


----------



## amphead

The loaded PS with 100K, responding well, set at 250vdc is what you are looking for. Edit: If it isn't stable possible regulator problem.


----------



## koike

Alright i'll try moving the heater wires around tonight.
 i'll be also doing regal's mod to run the tubes hotter.
 i might be buying some film caps to pop in.

 edit: heres an internal picture. could the heater wires being tied to the 290VDC output from the transformers be the cause of hum?


----------



## chobint

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_The loaded PS with 100K, responding well, set at 250vdc is what you are looking for. Edit: If it isn't stable possible regulator problem._

 

Yes, I figured that even if my PSU could not hit the full 250v loaded, that it would atleast be adjustable between 190v and 230v or something of the sort. This to me says that something must be wrong other than needing the ez80.

 And again forgive my noobdom, but what is a regulator? Is that the mosfet?

 If you guys need any more voltage readings, etc feel free to ask. Many thanks for all the help.


----------



## runeight

Quote:


  Originally Posted by *koike* /img/forum/go_quote.gif 
_Alright i'll try moving the heater wires around tonight.
 i'll be also doing regal's mod to run the tubes hotter.
 i might be buying some film caps to pop in.

 edit: heres an internal picture. could the heater wires being tied to the 290VDC output from the transformers be the cause of hum?_

 

On the AC side of the transformer, tying the wires together is no problem. 

 On the DC side, the heater wires should be twisted together and then run as close the metal chassis as possible wherever they go and as far away from all other wires as possible.


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Yes, I figured that even if my PSU could not hit the full 250v loaded, that it would atleast be adjustable between 190v and 230v or something of the sort. This to me says that something must be wrong other than needing the ez80.

 And again forgive my noobdom, but what is a regulator? Is that the mosfet?

 If you guys need any more voltage readings, etc feel free to ask. Many thanks for all the help._

 

The mosfets are Q1 and Q2 in the PS schematic. They are attached to the big heatsinks and are the active devices in the power supply regulator circuit.

 I think you'll have to replace these, both of them. I know it's really a pain because when I was debugging the prototype Bijou I killed mine a few times. But the behavior indicates that they are not working.

 The mosfets die when the PS is shorted for any reason and no matter how short a period of time. Even just an instant.

 After you replace the mosfets we can work on the other voltages. But you should still try to find an EZ81.


----------



## chobint

Ok, I'll replace them. Luckily EZ81 available local. Unfortunately soonest available mofsets can't ship for 10 more days ><. *braces for withdrawal*


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Ok, I'll replace them. Luckily EZ81 available local. Unfortunately soonest available mofsets can't ship for 10 more days ><. *braces for withdrawal*_

 

If your B+ is holding at the lower voltage you can still run and listen. Nothing will break.


----------



## Ferrari

This post is to answer some PMs I have got recently regarding my suggestion to use 100µF film cap for the output capacitor C5. Sorry that I can’t answer your PMs individually guys… that’s very time consuming for me!

 The desired capacitance (µF) of the output capacitor is depending on the impedance of the used headphone (Z[size=xx-small]headphone[/size]). To ensure an acceptable bass response, we need a –3dB point of the high-pass filter (formed by the output capacitor C5 and R13//Z[size=xx-small]headphone[/size]) at far under 20Hz (theoretically audible by human ears).

 The –3dB point can be calculated using the following formular: f = 1/(2π.R.C)

 => f = 1/{2π. (R13//Z[size=xx-small]headphone[/size]).C} = 1/{2πC.(10KΩ //Z[size=xx-small]headphone[/size])
 => C = 1/{2πf.(10KΩ //Z[size=xx-small]headphone[/size])} = 1/{2πf.(10KΩ.Z[size=xx-small]headphone[/size])/(10KΩ + Z[size=xx-small]headphone[/size])}

 In real life, Z[size=xx-small]headphone[/size] is of course not real Ohms, but… for the covenience we can assume it as [size=small]l[/size]Z[size=xx-small]headphone[/size][size=small]l[/size].

 Obviously you can see from the formular that, the _higer_ the [size=small]l[/size]Z[size=xx-small]headphone[/size][size=small]l[/size], the _smaller_ the output capacitor is required, and… the _lower_ the [size=small]l[/size]Z[size=xx-small]headphone[/size][size=small]l[/size], the _larger_ the output capacitor is required. In some post back, I suggested using a good 100µF film cap for high impedance headphones with [size=small]l[/size]Z[size=xx-small]headphone[/size][size=small]l[/size] = 300Ω which theoretically will result in a –3dB point at ~5.5Hz (at least). 
 It can’t hurt to use a larger film cap (220µF or 330µF) here if you can get it.

 To sum up… depending on the impedance of your headphone, you can calculate that for yourself and determine what you are going to use for the output capacitor C5. The stock output capacitor C5 = 470µF is theoretically adequate for a wide range of headphones, even the ones with [size=small]l[/size]Z[size=xx-small]headphone[/size][size=small]l[/size] = 32Ω . Keep in mind that many real world headphones are not able to reproduce low frequencies down to 20Hz !!!


----------



## amphead

Pabbi, also tight shots of the pots/wiring, as well as the input and output connections will probably help to analyze the situation.


----------



## pabbi1

Will do - give me a few hours, and I'll document in abundance.


----------



## pabbi1

Pics

Pic 1
Pic 2
Pic 3
Pic 4
Pic 5
Pic 6
Pic 7
Pic 8
Pic 9

 One thing, and I have tried this several ways - the shell of the XLR I have tied together, and have tried that grounded to the case, and not, and not tied together. No difference. Both make contact with the case, and are bolted to it with nuts / bolts.


----------



## amphead

Pabbi, carefully pack up the amp with bubble wrap and send it. We would need a super-macro camera to have any chance of finding a problem over the net. The pictures just don't have the resolution necessary to see what is wrong. My gut is that the wiring on the pots or input xlr have not been wired correctly but it just isn't apparent to me from the photos. Runeight? Ferrari? See anything? Namaanf/Amb are the Uber balanced mode experts, but are usually busy. So it's probably my shot, to figure this one out. If I had it by friday I would troubleshoot at Amb Laboratories, but I wouldn't want you to spend too much shipping. Although there are 2 high quality scopes available there, along with Amb's expertise. Edit: Priority mail is about $15.00 I think. If sent tomorrow, it might make it by friday. We would want tracking, if possible.


----------



## runeight

Unfortunately, I might have to agree. I can't discern enough from the pictures. Whereas, about 1 minute of scope measurements should diagnose the problem.

 I hope that you guys can arrange to work this out.


----------



## pabbi1

Drained and boxed. Including a balanced 650 & cable, as well as the botched pot (one good channel) in case the wiring guidance is a contributor.

 Thanks guys - seems like I'm always lowering the bar in DIY.


----------



## dBel84

No , you just insist on building the most complicated rigs that leave most of us mortals floundering 
	

	
	
		
		

		
			





 ..dB

 ps if it turns out to be something ridiculously simple, prepare to be 'egged' and ridiculed into submission


----------



## pabbi1

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_No , you just insist on building the most complicated rigs that leave most of us mortals floundering 
	

	
	
		
		

		
		
	


	




 ..dB

 ps if it turns out to be something ridiculously simple, prepare to be 'egged' and ridiculed into submission 
	

	
	
		
		

		
		
	


	


_

 

More ridiculously simple the better - I rather fancy myself the idiot savant. Now, I'll get back to my R-10 clones... and should I be able to do it, the proof is there that anyone can. Oh, and the path will be cleared for balanced Bijou for the tweaks section, once we all have a chuckle, and it isn't something far more sinister..


----------



## bhjazz

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Thanks guys - seems like I'm always lowering the bar in DIY._

 

NO WAY. The only way to push the limit is to get yourself in trouble. I'm behind you 100%!


----------



## chobint

Hey rune, would a switch between the B+ line and the amp board suffice as a tube warm-up circuit? or would i need to include the psu tube in it? thanks

 edit: and would you want the B+ floating in off position, or connected to ground thru a 100k 1w resistor?


----------



## pabbi1

As if this were not bad enough, I look on the website and find a 'Super Bijou' (in work)... oy vey. 
	

	
	
		
		

		
		
	


	




 Dare I ask what the delta might be, or should that be best left for another thread?

 <sigh>

 All shipped Ron, ygpm.


----------



## amphead

OK, I have my fingers crossed for a friday delivery.


----------



## amphead

Yes, indeed the eagle has landed. USPS priority mail worked very well this time. Everything arrived with no damage, unlike Jim Carreys handling of the package in Ace Ventura. Looking forward to the process of discovery on Pabbi's amp.


----------



## amphead

This is the way that I will be looking to wire the amp for balanced mode............


----------



## pabbi1

yes, I (think) followed Amb's balanced wiring - and originally for SE also, but removed that for (relative) simplicity. Ugly as it may be...


----------



## -=Germania=-

Hey, 

 I am looking strongly into making one of these things in a single ended configuration. 

 The kits look like a good idea for my situation and for the sake of ease to build. My better sources are not going to see as much benefit with my current Millet.

 Would $200 be sufficient? What is a good transformer to use and what would the cost on that be (place to get it)? 

 Anyone know of any powder coated cases under $40?

 I think that this will be a perfect intro for me into all tube designs and get into a bit of rolling....


----------



## pabbi1

Quote:


  Originally Posted by *-=Germania=-* /img/forum/go_quote.gif 
_Hey, 

 I am looking strongly into making one of these things in a single ended configuration. 

 The kits look like a good idea for my situation and for the sake of ease to build. My better sources are not going to see as much benefit with my current Millet.

 Would $200 be sufficient? What is a good transformer to use and what would the cost on that be (place to get it)? 

 Anyone know of any powder coated cases under $40?

 I think that this will be a perfect intro for me into all tube designs and get into a bit of rolling.... 
	

	
	
		
		

		
		
	


	


_

 

Transformers are best purchased from Angela (Angela Instruments: Online Catalog) in my experience (defined in the BOM), and have a look at the Nabu case - truest of bargains, with room for a DAC, or (tight) balanced. My expenditure is about $600 to date, with parts coming (literally) from 17 sources all over the world. 

 You might can do this for $200 SE, depending on attenuator / caps / tubes (quality & quantity) IFF you shop a LOT or chase the majority from Mouser, including caps. If you had a local surplus, all the more likely.


----------



## regal

The Nabu isn't really tall enough.


----------



## -=Germania=-

Would a single ended fit in a Hammond 1441-16?

 I would make ports for the appropriate components (tubes + transformer) to make it easier to do rolling + prettier!


----------



## n_maher

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_You might can do this for $200 SE, depending on attenuator / caps / tubes (quality & quantity) IFF you shop a LOT or chase the majority from Mouser, including caps. If you had a local surplus, all the more likely._

 

I fail to see how it's possible without using entirely surplus parts and I have no idea what for an enclosure. The Hammond trafo alone is going run $60 w/ shipping. 

 More to the point I'd lobby that a few more projects under the belt would be a good idea before coming face to face with a 300V B+.


----------



## naamanf

Quote:


  Originally Posted by *-=Germania=-* /img/forum/go_quote.gif 
_Would a single ended fit in a Hammond 1441-16?

 I would make ports for the appropriate components (tubes + transformer) to make it easier to do rolling + prettier!_

 

You could always do a bit of ground work and figure it out for yourself.


----------



## pabbi1

Quote:


  Originally Posted by *n_maher* /img/forum/go_quote.gif 
_I fail to see how it's possible without using entirely surplus parts and I have no idea what for an enclosure. The Hammond trafo alone is going run $60 w/ shipping._

 

Dang it - true I always underestimate since some of this I have laying around.
 OK, more like $300 bare minimum. 

 The Nabu is actually tall enough except for the tranny (assuming Hammond) - just needs vent holes.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Holland, I tried the top view of the Gem and it was too plain looking to me.

 How about this........





_

 

Is this a vector image, and can you post it? The only thing better might be to fill the socket square full black. The vector will make a far better engraving...


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_This is the way that I will be looking to wire the amp for balanced mode............




_

 

Yes, that looks right except that the pinouts on the cannon connector on the output are not correct. At least I don't think so. Pin 1 is usually grounded.

 Any progress??


----------



## amphead

Runeight, I have just ohmed out a few things with my meter, but have not started in earnest yet. Not until we have Amb's scope Saturday. Yeah, I wondered about the wiring on the output xlr in my diagram.


----------



## regal

Today a replaced the eletrolytic coupling caps with 80 uF Sprague oil filled can capacitors. It is amazings how much clarity comes thru now.

 What are the opinions of the Bijou with no NFB powering a pair of 300 ohm Sennheisers? My current headphones are 600 ohm and they definetaly sound better without the NFB.
 Would the ouput impedance be too high sans NFB to work with 300 ohm phones?


----------



## runeight

No, I don't think the Zo will be too high. Headphones are mostly resistive loads and high damping factors are not usually necessary.

 IIRC the Zo of the no NFB amp will be around 30R.

 amphead, let us know what you find at the inputs to each board as measured with respect to ground. Thanks for working on this.


----------



## rfsam

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Today a replaced the eletrolytic coupling caps with 80 uF Sprague oil filled can capacitors. It is amazings how much clarity comes thru now.

 What are the opinions of the Bijou with no NFB powering a pair of 300 ohm Sennheisers? My current headphones are 600 ohm and they definetaly sound better without the NFB.
 Would the ouput impedance be too high sans NFB to work with 300 ohm phones?_

 

Regal, I'm a bit confused by that difference between electrolytical cap and non-electrolytical one. Especially on 300-600R load.

 I checked the specs for the electrolytical cap that came with Jeff's kit (Panasonic TS-ED 470u/250V 105d Al Electrolytic). ESR of this cap is 0.37R on 120 Hz and less at high frequencies (i.e. 20kHz). Impedance (capacitive) of this cap at 120Hz is ~3 Ohm. I just don't see how ESR can make any difference especially when output Z is 30R and the load is 300-600R. ESI (equivalent serial inductance) is another thing. But at low frequencies it should be very low anyway and at high frequencies a small parallel cap with reduce it (that's the reason we have it there). Do you still have a 1uF cap in parallel to 80uf? My guess here is that 1 uF is kind of low for mid-high frequencies (doesn't lower total ESI enough) and we need a third cap in parallel (mid value - 80uF). But I just don't see here how the ESR can make any effect here unless the electrolytical cap is really a cheap one. Am I missing something else here?

 Runeight, could you comment on that?


----------



## JamSandwich

Hi Guys, just bought the Bijou kit from glass jar audio and waiting for delivery, so looking forward to the build 
	

	
	
		
		

		
		
	


	




 I'm based in the UK and am struggling with AWG (American Wire Gauge). The Cavalli site recommends 20awg wire for all internal connections and 22awg for connections from the transformer.

 None of the suppliers here in the UK seem to deal in (or know about awg) and I’m getting conflicting advice about how to convert to UK gauges. Can anyone give me the specs for the wire they are using in this build? Are you using solid or stranded core?


----------



## amphead

Pabbi, Runeight, the problem was narrowed down to wiring on the input connectors/stepped attenuators with the Bijou's troubleshooting following the testing of the Krmathis Beta22 group build. More info to come, after recovering from driving, testing Beta22, testing Bijou, and more driving.


----------



## adamus

I bit the bullet and ordered boards and parts, so another bijou will hopefully live within a couple of months. 
 This is going in 330 x 230 mm hifi2000 case. all tall parts on the underside of the boards. I will use obbligato caps in place of the mkp's. 

 just deciding on a transformer. I can either go with the dax370, which is $66 + $30 shipping. Or go with the Rcore from vt4c. My issue with that is it doesnt have the 240v primaries, so i suspect all my voltages will be on the hot side. it would save me $40, and i am sure could tweak some values to bring down the heater voltage etc. 

 what are your views? anyone used the Rcore?


----------



## chobint

hey jamsandwich, try using this online wire gauge converter. Comes in handy from time to time.

 PS>Replaced most of the electrolytics with film caps and she's kicking like a whole new beast. Makes me wonder what Ferari's souped up bijou sounds like. Now if those mosfets would just get here...


----------



## regal

Quote:


  Originally Posted by *rfsam* /img/forum/go_quote.gif 
_Regal, I'm a bit confused by that difference between electrolytical cap and non-electrolytical one. Especially on 300-600R load._

 

Read about caps here, ESR has little correlation with sonics.

ecp.cc


----------



## rfsam

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Read about caps here, ESR has little correlation with sonics.

ecp.cc_

 

Regal, thank you. I mentioned ESR because people (and in this thread too) are talking about ESR when they compare the audio quality of different caps. I don't think (as I mentioned before) ESR matters that much (agree with you here). But what parameter "drives" the cap's sound quality? Unfortunately the link you gave me doesn't have an explanation (it does have some basics and practical comparison of different brands - a very good source on choosing a cap!) on why there is hearable difference. I think it's self inductance (ESI).


----------



## regal

The only measuring device for ranking capacitors are the ears.


----------



## adamus

for my build i am quite tempted to use the 70uf obbligato oil film caps. 125mm tall they will have to be mounted through the case with a cap mounting kit.

 the only phones i really listen to are hd650's. so corner frequency will be fine (7 hz, pushing 70 for 32 ohms). 

 or i could just stick a $2 electrolytic in there.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, Runeight, the problem was narrowed down to wiring on the input connectors/stepped attenuators with the Bijou's troubleshooting following the testing of the Krmathis Beta22 group build. More info to come, after recovering from driving, testing Beta22, testing Bijou, and more driving. _

 

Ron, thanks again - and I have been suspecting the attenuators for a while, but with no real basis. I thought all possible combinations of input had been covered, but, maybe not. IF these attenuators won't work (why I sent the mangled one along as a sacrifice), I'll definitely trade them out in a heartbeat for something else.


----------



## amphead

Pabbi, when I re-wire the amplifier, I'm going to put some ordinary 100K pots in for testing purposes. The other thing that I will do is to do the grounding mod, to reduce/eliminate any noise issues, if you would prefer that. Let me know. thanks


----------



## runeight

Quote:


  Originally Posted by *rfsam* /img/forum/go_quote.gif 
_Regal, thank you. I mentioned ESR because people (and in this thread too) are talking about ESR when they compare the audio quality of different caps. I don't think (as I mentioned before) ESR matters that much (agree with you here). But what parameter "drives" the cap's sound quality? Unfortunately the link you gave me doesn't have an explanation (it does have some basics and practical comparison of different brands - a very good source on choosing a cap!) on why there is hearable difference. I think it's self inductance (ESI)._

 

This problem is just too squirrely to handle. Discussions that were started years ago are still going on.

 My sense of this is that it's not the ESR or ESI. ESI only affects very high freqs and ESR is no different from putting a resistor in series with the headphone output.

 The main thing that seems to be a factor is the nature of the construction itself. The normal, linear R-C-I parts of the components are pretty easy to account for in what they do.

 But the construction seems to be a factor. And by construction I mean the actual materials used for the plates and, especially, the dielectric. Dielectrics are not, at a molecular level, uniform sheets of stuff. In electrolytics they are very far from uniform sheets of stuff. One would think that in the macro sense the fine-grained attributes of the dielectric and electrode materials would just average out to simple R-C-I. But for some reason that I don't understand, these fine-grained structures seem to matter. At least, this is what I remember from reading about this a long time ago.

 It's like tube rolling. How can two tubes of the same type with exactly the same electrode construction and spacings sound different?? But for some reason we think that they do.

 So, I don't know . . .


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I bit the bullet and ordered boards and parts, so another bijou will hopefully live within a couple of months. 
 This is going in 330 x 230 mm hifi2000 case. all tall parts on the underside of the boards. I will use obbligato caps in place of the mkp's. 

 just deciding on a transformer. I can either go with the dax370, which is $66 + $30 shipping. Or go with the Rcore from vt4c. My issue with that is it doesnt have the 240v primaries, so i suspect all my voltages will be on the hot side. it would save me $40, and i am sure could tweak some values to bring down the heater voltage etc. 

 what are your views? anyone used the Rcore?_

 

How hot? Having a little extra B+ voltage before the regulator might not be so bad.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, when I re-wire the amplifier, I'm going to put some ordinary 100K pots in for testing purposes. The other thing that I will do is to do the grounding mod, to reduce/eliminate any noise issues, if you would prefer that. Let me know. thanks_

 

How can I say no to that? Your generosity is, well, so undeserved... and to think I was gonna live with the copper tape, or plug in fixed resistors on the NFB, and hope.

 Sadly, if these don't work, I'd also be gunshy about Goldpoints as well - what attenuators is everyone using? Certainly not just rk27? Are rk40 a step in the right direction? Oh, and I would plunk the $1156 shipped for the rk50, but, they won't fit.


----------



## n_maher

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Are rk40 a step in the right direction?_

 

Tis a sad day, last time I checked with my German supplier even his supply of RK40s (in log taper) was exhausted. I fear that we've now seen the last of them, even at elevated aftermarket prices.


----------



## pabbi1

N/m... search is my friend. <sigh>.


----------



## adamus

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_How hot? Having a little extra B+ voltage before the regulator might not be so bad. 
	

	
	
		
		

		
		
	


	


_

 

around 249v at the wall. would the r core be ok do you think?


----------



## amphead

Pabbi, Runeight, my balanced source is not working, so I'll build this simple single chip unbalanced to balanced converter on perf board for the purposes of listening to the amp once it is rewired. Edit: if you look closely, this circuit takes in a left or right signal and creates the additional signal 180 degrees out of phase for V+ and V-


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_around 249v at the wall. would the r core be ok do you think?_

 

What is the HV secondary of the RCore rated at with a norm mains voltage?


----------



## adamus

Audio Catalog

 its the 80 - 36 model. 260, 230 (unused), 3.15,3.15,6.3


----------



## Ferrari

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_PS>Replaced most of the electrolytics with film caps and she's kicking like a whole new beast. Makes me wonder what Ferrari's souped up bijou sounds like..._

 

Time after time, it's a pleasant ears massage to listen to this amp, especially with a couple of these gorgeous 6N30P-DR in the front end.


----------



## GeWa

Hey Ferrari, where did you get those from?

 Regards


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Audio Catalog

 its the 80 - 36 model. 260, 230 (unused), 3.15,3.15,6.3_

 

I think you should be alright with 249V on the primary using the 260V secondary.


----------



## adamus

and what about the heaters? cheers for the advice by the way.


----------



## runeight

IIRC, the heater secondaries are 3A? I think you'll be ok here too. But as we know the heater voltages can vary. And we'll have to see if you can use the EZ80 or need to try the EZ81. This choice affects the heater current draw.

 It is possible to put small resistors in the heater circuit if that turns out to be a problem.


----------



## adamus

cheers, considering the 370dax will cost me $100, and then i would get stung with customs i think i will go for the r core, save me at least $50, probably more.


----------



## rfsam

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_It's like tube rolling. How can two tubes of the same type with exactly the same electrode construction and spacings sound different?? But for some reason we think that they do.

 So, I don't know . . ._

 

Runeight, Regal, thank you! That's an interesting discussion. I'm not sure that I'm ready to experiment with different capacitors but will keep that in mind.


----------



## Ferrari

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_Hey Ferrari, where did you get those from?

 Regards_

 

I got those 6N30P-DR as a present along with a couple of 6H8C (1578, metal base) from an old colleague from Ukraine 
 (we worked together for (AT&T)/Lucent R&D in the 1990s).


----------



## dBel84

You have good friends / colleagues 
	

	
	
		
		

		
			





 , I still need to get myself a pair to try on the EHHA. From everything I read about them, they sound very good when applied correctly..dB


----------



## amphead

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_I got those 6N30P-DR as a present along with a couple of 6H8C (1578, metal base) from an old colleague from Ukraine 
 (we worked together for (AT&T)/Lucent R&D in the 1990s)._

 

Ukrainians Rock! Those are some great looking and probably great sounding tubes. 

 Pabbi, I have started building the unbalanced to balanced converter. I purchased the chips(TL074), caps, resistors and perfboard, today. Give me some time and we will get to the bottom of this problem.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Ukrainians Rock! Those are some great looking and probably great sounding tubes. 

 Pabbi, I have started building the unbalanced to balanced converter. I purchased the chips(TL074), caps, resistors and perfboard, today. Give me some time and we will get to the bottom of this problem._

 

No hurries at all, but I am rather speechless at the extent to which you are having to go... pity shipping the Azur would have been a bit pricey...


----------



## adamus

gents, as i have time and patience on my hands, what are your favourite tubes for the bijou in a reasonable price bracket. 

 I may aswell go for the best bang for buck from the start. 

 Cheers


----------



## willisv

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_gents, as i have time and patience on my hands, what are your favourite tubes for the bijou in a reasonable price bracket. 

 I may aswell go for the best bang for buck from the start. 

 Cheers_

 

If you end up using the r-core for a power supply you could buy some amperex 8416 tubes for the input. They are supposed to be very similar to the expensive amperex 6922 tube at a fraction of the cost. I use them in my Bijou and they sound very nice but you have to run 12V to the heaters, this is no problem with the r-core. You should be able to find them for $15 - $20 each.


----------



## miky

Quote:


  Originally Posted by *willisv* /img/forum/go_quote.gif 
_If you end up using the r-core for a power supply you could buy some amperex 8416 tubes for the input. They are supposed to be very similar to the expensive amperex 6922 tube at a fraction of the cost. I use them in my Bijou and they sound very nice but you have to run 12V to the heaters, this is no problem with the r-core. You should be able to find them for $15 - $20 each._

 

Can you supply a wiring diagram for how you wired amperex 8416 and r-core (R0080-036)?


----------



## adamus

cheers


----------



## adamus

it is just 6dj8 with 12v heaters.


----------



## willisv

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_Can you supply a wiring diagram for how you wired amperex 8416 and r-core (R0080-036)?_

 

There will be 4 gray secondary wires that you use for the heaters. Twist two of them together and measure the voltage between the twisted pair and each single pair then measure between the single pairs. When the voltage from the twisted pairs and each of the single pairs measures 6-7 volts and the two single pairs measure 12-14 volts then you have the right combination. I ended up with 14v on my r-core and used a 5 watt 4.7R resistor to drop the voltage down to 12V.


----------



## adamus

so, just to clarify,

 You used 1 secondary to power the rectifier and output heaters, then series that with the other secondary to give the 12 v. Also, i tak it we can just ignore the CT on the heater secondaries?

 Could you not have used the 5v taps to get the 12v without resistors?


----------



## willisv

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_so, just to clarify,

 You used 1 secondary to power the rectifier and output heaters, then series that with the other secondary to give the 12 v. 

 Could you not have used the 5v taps to get the 12v without resistors?_

 

To be honest with you I didn't try that. Mazuki would be the one to talk to, he's the one that helped me wire up my R-core.

 Edit: I just checked my R-core and there is only one 5v tap, so I'm pretty sure that won't work.


----------



## miky

*willisv*
 Thanks for your input


----------



## dBel84

not sure if this is a good sign or a sign that I need to step out for a while but here is the original r-core discussion. scroll down to PRR's post..dB


----------



## miky

Thank you dBel84, it is very helpful.


----------



## amphead

Pabbi, I will be finished soldering/constructing the unbalanced to balanced converter tonight. I have a boat trip on Rollins Lake tomorrow, which is almost a 2 hour drive, but then tomorrow night it will be time to feed my unbalanced source through the converter and into your amp to get things moving.


----------



## pabbi1

Ron, enjoy your weekend - we all need a rest. Thanks for the update, and the above and beyond - still enjoying the heck out of our previous 'collaboration'...


----------



## adamus

started stuffing....


----------



## Mazuki

Quote:


 Can you supply a wiring diagram for how you wired amperex 8416 and r-core (R0080-036)? 
 

The R-core is the best transformer option in my opinion, I liked it so much I bought two!

 You have to be careful though, as the heater supply is not floating, so when changing to 12.6V heaters, you have to keep one leg connected to the HV supply. Here's a diagram by runeight explaining the setup:






 Use this in conjunction with PRR's description.


----------



## amphead

After reading the specs on the R-core's quiet characteristic in close quarters, I tend to agree that it is a good choice.

 Well, Pabbi I am going to be firing up the amp tomorrow. Lost some time do to the holiday. I'm a little bit beat, after risking my crazy brother-in-laws sea-doo ride. It is a small speed boat, and he likes to jump wakes, and as a passenger I took a beating.  Edit: if the converter works well, I'll send it with the amp so that you can run single ended sources through your amp as well as your usual balanced Azur/phono gear.


----------



## adamus

Quote:


  Originally Posted by *Mazuki* /img/forum/go_quote.gif 
_The R-core is the best transformer option in my opinion, I liked it so much I bought two!

 You have to be careful though, as the heater supply is not floating, so when changing to 12.6V heaters, you have to keep one leg connected to the HV supply. Here's a diagram by runeight explaining the setup:






 Use this in conjunction with PRR's description._

 

one leg connected to HV supply? could you explain that in more detail to me.


----------



## runeight

The heater secondaries are wired so that one of them supplies 6.3V. This includes the rectifier. This secondary is wired to pins 3 & 4 of the terminal block.

 Pin 3 is supplied with the DC heater bias from the internal PS circuitry. Thus, the other secondary is wired in series with the first secondary to make 12.6V while one of its leads is also connected to pin 3 of the terminal block. This ensures that both secondaries see the heater bias.


----------



## adamus

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_
*Pin 3 is supplied with the DC heater bias from the internal PS circuitry.* Thus, the other secondary is wired in series with the first secondary to make 12.6V while one of its leads is also connected to pin 3 of the terminal block. This ensures that both secondaries see the heater bias._

 

Thats the bit that helps, Cheers.


----------



## funch

From the sounds I'm hearing, I'm gonna need at least one new 6N6P soon (wierd intermittent crackling sounds, switched 6N6P's, sound followed tube).
 There doesn't seem to be any shortage of them on ebay, so I was wondering
 if anyone here has had dealings with any of the ebay dealers (Ukraine, etc.), or if there's a better place to find them? Thanks.


----------



## chobint

So, I got my new mosfets and ez81 in and am sitting at 250v stable now. Got some new 6dj8's too, but I had a question before I put my new tubes in...

 EDIT: Revised. Found this pretty good tutorial  on how to implement a standby switch, but I still wanted to clear a few things up.

 Does the Bijou need a standby switch? The article mentions that amps with a controlled warm up rectifier don't need it, and since I'm unfamiliar with amp design features I can't tell if the Bijou has this or not.

 It also says that a 250VAC 1A in the B+ line will suffice for a standby switch, will this be heavy enough duty for the Bijou? I was planning on using atleast a 6A 250VAC switch like this partsxpress rocker, but I don't know if VAC and VDC are equivalent or what.
 Can anyone help clarify? Thank you.


----------



## runeight

chobint, the main reason for the tube rectifier is for the slow start on the PS. If everything is working normally you should not need a B+ standby switch. I don't have one and Bijou has been running ok for several years now.


----------



## chobint

cool, I was unaware of said feature. One less thing for me to mess up


----------



## amphead

Yeah, the slow power up of tube rectifiers, is a big advantage over the hard slam of High Voltage from solid state rectifiers. While waiting for heaters to provide current flow.


----------



## adamus

stuffing complete







 Looking at the schematic i am fine to leave out d7, led, rled. Just a sanity check, i can just leave this points on the pcb untouched.


----------



## runeight

yes, you can leave them out.


----------



## adamus

cheers. just waiting on wire from navships ebay store, transformer (RCORE) from Hongkong. I have a case from hifi2000. Certainly looking forward to firing this up.


----------



## jamess71

I am finally getting ready to start this build. I bought the kit from Jeff so I have most of the stuff needed. I need to order a transformer. 

 Is the R Core the recommended over the 270DAX? Where should I order it from? Other than that just a case, I think I might try the nabu for this one. 

 Nice looking build so far adamus. What hifi2000 case are you getting? those things are sweet. 

 Thanks 
 James


----------



## adamus

already got it, its this one: modushop.biz

 its the 230 X 330 mm version/ only cost me 29 euros.


----------



## willisv

Quote:


  Originally Posted by *jamess71* /img/forum/go_quote.gif 
_I am finally getting ready to start this build. I bought the kit from Jeff so I have most of the stuff needed. I need to order a transformer. 

 Is the R Core the recommended over the 270DAX? Where should I order it from? Other than that just a case, I think I might try the nabu for this one. 

 Nice looking build so far adamus. What hifi2000 case are you getting? those things are sweet. 

 Thanks 
 James_

 

This is a good place to get the R-core
Audio Catalog


----------



## adamus

thats where i ordered mine from. Shipping was about $28.


----------



## adamus

I am putting together some potential layouts in visio. Can anyone critique this?


----------



## willisv

Looks good to me, mine is quite a bit tighter and no noise problems.


----------



## InSides

Several sanity check questions before deciding whether to go ahead with a Bijou build [actually, having it built as DIY to me goes as far as tightening a few bolts].

 I would get the kits from Jeff @ GlassJar and the transformers from Angela.

 But anyway, looking over the thread, it seems that in order to fully incase the amp, the case needs to be over 3.5" high. Hence, I've thought of maybe mounting the tube sockets to the top cover of the case.

 1. Would it be possible to bolt the boards to the bottom, and "air-wire" a bunch of top mounted tube sockets?

 2. If possible, would these sockets be OK?

9-pin Miniature Socket @ TubeDepot

 3. Should I be looking into getting shielded sockets? Or is leaving the tubes exposed OK?

 4. Would this wire be good for hookup and "air-wiring" the sockets?

Teflon Coated 20AWG Wire @ TubeDepot

 5. Finally, would this wire be good enough for heater and B+ wiring?

Cloth Covered [600V Insulation] 20AWG Wire @ TubeDepot

 Thanks!


----------



## amphead

If you do not air-wire use this socket.
9 Pin PC Mount Socket

 Tube shielding is not necessary, just use the above socket, or the one below.

 Air wiring is fine, just more effort involved. Then you would use the socket you found here...http://www.tubedepot.com/sk-9pinb.html

 Yes, that wire is fine for everything, and you can also use the cloth insulated wire if you wish.


----------



## amphead

OK, now for some exciting news! Pabbi I have rewired your amplifier with Alps pots and injected a signal for left and right channels with the unbalanced/balanced converter directly into your amp boards. Sounds heavenly. Rich bass, clear highs and mids that are slighty recessed or just not over-done but sounding very good. Unlike your earlier experience, sound is loud in balanced mode. Your stepped attenuators will be checked, out of the circuit and re-installed if all tests good. Background noise is minimal even without the ground mod. Certainly nothing like, the problem I had earlier with my amp. Listened to some light jazz, while enjoying what a balanced Bijou can do. Melted into my chair for the whole cd. So, I will be trying the amp with your stepped attenuators tomorrow night. You mentioned that your preferred balanced source is with the Azur. Are you using phono/phono preamp? thanks


----------



## pabbi1

The Azur is the Cambridge 840c, just an upsampling CDP. But, the news is simply outstanding, and glad you are experiencing what balanced _can_ do... it is just, well, different, and I expect the balanced Bijou will be just about the best possible, with a couple of notable exceptions.

 Then, you certainly deserve to hear the Obligatos properly burned in... 

 And, seriously, if the pots are problematic, (known) replacements can be delivered in short order.

 Question is, would it be so loud to require 250k pots vs 100k (assuming you are using 100k or, perhaps, 50k)?


----------



## fishski13

just to clarify before i order up some tubes - with a Hammond 370 DAZ, has anyone had any issues running these:

 EZ81 - 1 A
 ECC99 - 600 mA 
 6Np1 - 800 mA

 this gives me 3.8 A on a 3.5 rated transformer. 

 thanks

 PACE


----------



## dBel84

iirc folk have been running the EZ81 from a separate heater supply - there have been so many mods, I have lost track..dB


----------



## fishski13

The Bijou Headphone Amplifier

 i'm going by this, and i know Alex is drawing 2.8 A from his 2.5 270 transfo.


----------



## Ferrari

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_just to clarify before i order up some tubes - with a Hammond 370 DAZ, has anyone had any issues running these:

 EZ81 - 1 A
 ECC99 - 600 mA 
*6Np1 - 800 mA*

 this gives me 3.8 A on a 3.5 rated transformer. 

 thanks

 PACE_

 

*6Np1 - 800 mA* ???
 Is this a suitable tube for the Bijou??? 
	

	
	
		
		

		
			




 I didn't know of the existance of it!


----------



## adamus

I am assuming he meant 6N1P


----------



## fishski13

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I am assuming he meant 6N1P_

 

oops
	

	
	
		
		

		
		
	


	




. yes, 6N1P.

Sovtek 6N1P

http://www.amplimo.nl/download/6n1p.pdf

 looks like it's speced at 600 mA?


----------



## Ferrari

Now we are talking about the same thing. The 6N1P needs ~600mA indeed, so a Hammond 370 should be sufficient!


----------



## amphead

Pabbi, I have installed one of your stepped attenuators in the right channel, while leaving one Alps pot in the left channel. One thing became immediately apparent on the stepped attenuator. The high side of the attenuator was not connected to the input signal from the source. I rewired it to make contact at the point of highest resistance, powered on and bingo. The stepped attenuator now works very well. Running the stepped attenuator and Alps pot in L/R channels gives 2 sonic impressions. Attenuator is deeper in tone compared to the Alps pot. Both sound great only slightly different flavor. Now to start wiring up the amplifier into it's permanent configuration. Spatial dimension and separation are very nice. You get lost in the music very easily. I'm in a hypnotic musical trance. Well done Alex! The balanced Bijou is a real contender for the gold medal!  Edit: I'm amazed that the unbalanced/balanced converter has the fidelity to pass such a clean signal! Edit: it may be possible to leave your amplifier in the original configuration without the ground mod. Not hearing significant background noise.


----------



## fishski13

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Now we are talking about the same thing. The 6N1P needs ~600mA indeed, so a Hammond 370 should be sufficient!_

 

great!

 ordered tubes (Tube Depot), transfo (Radio Daze), Sonicaps (Sonic Craft) and expecting packages from Digikey and Mouser today and tomorrow. hope to have the boards stuffed this week. i'm waiting to order an enclosure until i have the boards ready and the transfo in hand, and will buy one large enough to build a balanced Bijou - i'm only building a SE for right now.

 i miss the smell of solder. 

 PACE


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, I have installed one of your stepped attenuators in the right channel, while leaving one Alps pot in the left channel. One thing became immediately apparent on the stepped attenuator. The high side of the attenuator was not connected to the input signal from the source. I rewired it to make contact at the point of highest resistance, powered on and bingo. The stepped attenuator now works very well. Running the stepped attenuator and Alps pot in L/R channels gives 2 sonic impressions. Attenuator is deeper in tone compared to the Alps pot. Both sound great only slightly different flavor. Now to start wiring up the amplifier into it's permanent configuration. Spatial dimension and separation are very nice. You get lost in the music very easily. I'm in a hypnotic musical trance. Well done Alex! The balanced Bijou is a real contender for the gold medal!  Edit: I'm amazed that the unbalanced/balanced converter has the fidelity to pass such a clean signal! Edit: it may be possible to leave your amplifier in the original configuration without the ground mod. Not hearing significant background noise._

 

So, it was a case that I was so daft I couldn't figure out how to work around a (defective?) pot(s)? That will require a post regarding those pots for the rest of the great unwashed. Now I reign unchallenged as the LCD (lowest common denominator) in DIY. Goooooal!

 Ron, simply great - do we have a convert to the dark (balanced) side? And, it isn't even burned in yet... if the ground mods aren't needed, then by all means minimize your time. It is a real testiment to the design that there isn't any noise as tightly packed in as those components are.

 I do need to raise a question to the group: Tube dampeners - rewards and downsides? I don't have the most expensive tubes (6n1p and 6n6p), and, yes, I'll need to try myself, but any consensus? Doesn't sound like Ron is hearing any microphonics...


----------



## n_maher

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Now I reign unchallenged as the LCD (lowest common denominator) in DIY. Goooooal!_

 

I believe that I often supply competition for that label. 
	

	
	
		
		

		
		
	


	




  Quote:


 I do need to raise a question to the group: Tube dampeners - rewards and downsides? I don't have the most expensive tubes (6n1p and 6n6p), and, yes, I'll need to try myself, but any consensus? Doesn't sound like Ron is hearing any microphonics...  
 

I've used them but can't say that I've ever really heard an upside or downside. I've had microphonic tubes and tried them with no benefit. But they certainly add to the geek factor and provided you get them at a modest cost that may make it worth it regardless of their sonic contribution.


----------



## pabbi1

Got these off eBay for about $.85 each shipped, so it will look cool if nothing else. I also understand they can be gotten at the auto parts store. 

 Question is, any benefits at all on the rectifier tubes, or just on the amp boards?


----------



## ericj

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_iirc folk have been running the EZ81 from a separate heater supply - there have been so many mods, I have lost track..dB_

 

I'm running EZ81 + 6n1p + 6n6p off just the one trafo. No issues.


----------



## amphead

fishski13, looks like you are well on your way to building a great tube amp!

 No reason not to use tube dampeners Pabbi. Microphonics are not prominent, if at all on your amp as it stands. Probably deep into voodoo territory to use them on the rectifier tubes.


----------



## runeight

say, amphead, great news on Pabbi1's amp. I was pretty sure that signal was not getting to the inputs. Thanks for working all of that out. 
	

	
	
		
		

		
		
	


	




 So, does it sound different from the single ended version of the amp?


----------



## fishski13

pabbi1,
 we expect a full report and pics of course 
	

	
	
		
		

		
		
	


	




.

 re: chassis venting for an enclosed balanced Bijou. i'm looking at a Par-Metals 20-Series 19x12x5 enclosure and am wondering if i should ask for more vent holes on the top. the pic is standard with vents on sides, top, and bottom - another $20 for extra vents. 






 PACE


----------



## runeight

This just depends on how long life you want out of the components. 
	

	
	
		
		

		
			





 You'll have 10 tubes in the box for a fully balanced amp. Average 4W per tube for the heaters, that's 40W in the box from the tube heaters alone. Add another 5-10W for the rest of the stuff that's 45-50W. 

 So, just think about having a 50W bulb in the box.


----------



## pabbi1

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_pabbi1,
 we expect a full report and pics of course 
	

	
	
		
		

		
		
	


	




.

 re: chassis venting for an enclosed balanced Bijou. i'm looking at a Par-Metals 20-Series 19x12x5 enclosure and am wondering if i should ask for more vent holes on the top. the pic is standard with vents on sides, top, and bottom - another $20 for extra vents. 

 PACE_

 

To emphasize Alex's point, this is what mine looks like, and I am VERY concerned with ventilation, even though there are holes over each tube. The Nabu is only 3.5" tall, no bottom vents, and no holes on the sides (yet)... short of some surplus MercuryCadmiumTelluride (used to cool the electronics in fighter jets), I'm really not sure what to do, except run her with the top down, and some security netting to keep my cats out of it... fans, a la the LD VI? Always something <sigh>.

 ps - Ron, being conceived in New Orleans - during Mardi Gras, no less - don't think I hadn't already consulted with Marie Laveau on those attenuators. Voodoo and DIY are often eerily similar.


----------



## fishski13

Alex and pabbi,
 thanks. i will get the entire cover slotted with vents. the 5" height will help a bit too. i am also planning a custom faceplate from FPE that will more or less frame an acrylic window that will be spaced off/mounted on the backside with 1/8 off-sets, thus creating a continuous gap all around to create more ventilation. plus, i get to look at the glow of tubes 
	

	
	
		
		

		
		
	


	




. 

 this amp would be on the very top of my hi-fi shelf, well away from my 1 yr. old daughter. i have obvious safety concerns and would like to go with a totally enclosed chassis. 

 PACE


----------



## amphead

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_say, amphead, great news on Pabbi1's amp. I was pretty sure that signal was not getting to the inputs. Thanks for working all of that out. 
	

	
	
		
		

		
		
	


	




 So, does it sound different from the single ended version of the amp?_

 

More channel separation, and the differential noise canceling brings out detail somewhat. Spatial depth is increased. Sound is lush!


----------



## regal

Where did you find a case big enough to house the balanced Bijou ?


----------



## fishski13

[/IMG]

 here's a layout for a balanced with a 16x12 boundary. the 370 DAZ transfo's will just squeeze in on the left. i assume dividers should be placed inbetween the transfo and rectifying stages, and the rectifying and output stages. how far apart do the transfos need to placed from one another to reduce flux interference and potential hum? maybe i should have gone with the vertical mount DAX and placed them at 90 deg to one another? i guess i could still mount the DAZ i've already bought vertically and get a DAZ for the second one. any suggestions?

 the R-channel boards are mirrors of the L-channels, with the boards stuffed on the underside and flipped. the input wiring will dissect the two channels down the middle, with the input jacks and output jacks/potentiometers mounted directly in-line back to front respectively. the heater wiring feeds the outsides of the boards, with the R-channel heaters crossing the input signal perpendicular at only one point, right above the top boards of the L/R-channels. 

 i will try messing around with a lay-out for a 16x16 chassis. constructive criticism is appreciated 
	

	
	
		
		

		
		
	


	




.

 PACE


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## fishski13

[/IMG]

 here's a 16x12 layout i like a bit better. i can place one DAZ transfo between the two PS boards, with plenty of space behind for a second DAZ or DAX. i would then place only one divider between the PS/transfos and the amp boards.

 my parts from Mouser should be here shortly. cleaning up the workbench for some soldering later on.

 PACE


----------



## pabbi1

You will want more room on the right hand side for (presumably) your input wiring, and may well consider the interior signal wiring as well. Looks like you will have plenty of room for some discrete pathways - a weakness with the Nabu case (at 18.5"x10" just barely enough room, forcing route compromises).

 Otherwise, looks good...


----------



## fishski13

thanks pabbi!

 yes, you're right, i will be using two TKD potentiometers and will have to space out the amp boards just a bit. i will have ample room for the XLR and RCA input jacks on the rear and using some shielded Mogami mic cable to the pots. the output jacks to the headphones will be mounted just below the pots. the 5" height should give me ample wiggle room as long as i can keep the input wiring to the pots "riding high" with a couple of tall threaded rods supporting mid-way, freeing up space below for the output wiring. 

 PACE


----------



## amphead

fishski13, ideal balanced Bijou chassis size would work out to 11 x 19 x 4 inches. And if your stepped attenuator is large then 12 x 19 x 4 nches would be better. This would work out to 2 inches more width and 1 inch longer than Pabbi's case. And 1/2 inch taller. In the real world though, 12 x 20 would probably be easier to get. Edit: if you don't mind the case being really large, then about 4.5 inches tall or more will give you better ventilation. Edit: the balanced Bijou is certainly worth the large chassis size. Think old school Marantz style chassis.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_fishski13, ideal balanced Bijou chassis size would work out to 11 x 19 x 4 inches. And if your stepped attenuator is large then 12 x 19 x 4 nches would be better. This would work out to 2 inches more width and 1 inch longer than Pabbi's case. And 1/2 inch taller. In the real world though, 12 x 20 would probably be easier to get. Edit: if you don't mind the case being really large, then about 4.5 inches tall or more will give you better ventilation._

 

thanks. i've just realized that i'm going with some larger GenI Sonicaps at C3,4 and a GenII at C6, and will no doubt add others down the road. this amp could be a tweaker's delight, and i should provide more room for the amp boards. plus, going with 2 potentiometers instead of a single balanced attenuator makes things a bit tighter. at least the TKDs i'm buying have solder tabs, unlike the pain in the ass pins on a Blue Velvet, albeit at x4 the cost. 

 Par-Metals has an anodized 16x16x5 Series-20 for only $3.50 extra over the smaller $86 16x12 chassis - go figure. a divider is another $12. space isn't an issue. lead time is a week plus shipping. i may also just go with the cheaper black painted chassis since i'm going to be using an FPE faceplate anyway. 

 just finished whipping up the PS board. coming from a tube noob, and one that has only DIYed low voltage S.S., those 470u/450V Panny caps are HUGE!

 PACE


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## amphead

The 16 x 16 will work just fine, but they claim to make any dimension you want. Looking at Pabbi's layout 16 inches for the long dimension might not allow for a "logical" layout. If It was me, I would get one that's 12 x 20 x 5.25 or even the one that they mention at 12 x 19 x 5.25 which is off the shelf and black anodized for ~$96.00. Or the one with less "bling" that is clear anodized in that dimension for ~$81.00. If I "pull the trigger" on a balanced Bijou, I will do the black anodized at 12 x 19 x 5.25 for my build. The only issue is whether or not they provide vents like they do on the 20 series.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_The 16 x 16 will work just fine, but they claim to make any dimension you want. Looking at Pabbi's layout 16 inches for the long dimension might not allow for a "logical" layout. If It was me, I would get one that's 12 x 20 x 5.25 or even the one that they mention at 12 x 19 x 5.25 which is off the shelf and black anodized for ~$96.00. Or the one with less "bling" that is clear anodized in that dimension for ~$81.00. If I "pull the trigger" on a balanced Bijou, I will do the black anodized at 12 x 19 x 5.25 for my build. The only issue is whether or not they provide vents like they do on the 20 series._

 

good call. i've thought about the 12 series, in those same dimensions as well. when i inquired about adding more vents to the 20 series on the top alone, they said it was a flat $20. i will call tomorrow about the cost to vent a 12 series and report back. their webite says that the 12 series has "Optional vent holes are available on top, bottom or sides." - i assume this to mean realitively cheap compared to a total custom job.

 PACE


----------



## amphead

Pabbi, I have done the preliminary rewiring, without shielding on the pot to board wires. The shielding will be added tomorrow. So this is the first time anyone has heard a balanced Bijou with attenuators in both L/R channels.  So....... whats the verdict? Orpheus owners would be plunking down some cash on a balanced Bijou. I'll risk putting it in the commercial grade category, at the upper 1 percent of gear out there. It absolutely kicks some serious axx! I have heard some really good gear in 2008 too, so my ears know what to listen for. Alex you really *need* one of these! Hard to believe that hacks can build something that compares so well with commercial gear. There is a real "intimacy" with the music that I can now appreciate with both attenuators installed. The attenuators really kicked it up a notch vs the Alps pots. 
 The sound is [size=x-large]SPACIOUS![/size]


----------



## pabbi1

Welcome to the dark side... 
	

	
	
		
		

		
		
	


	




 And with cheap tubes to boot.

 There will be a couple of Texas head-fi meets (one in Austin even), so maybe Alex can get out for a listen...


----------



## fishski13

called Par-Metal re: venting option on a 12-Series and talked with a very helpful Jeanette - "Just fax me a picuture or drawing. As long as it's not too intricate, venting will cost a flat $20". i will be placing my order tomorrow.

 i should have the amp boards stuffed tonight. i've been matching additional resistors and setting them aside for when it comes time to build the second set of boards for balanced. for right now, i'm just excited to hear the Bijou un-balanced.

 PACE


----------



## amphead

Wired up the left channel with shielded wire. Left the right channel unshielded for the A/B on background noise. Lets just call the left one the quiet channel. With no music playing there is dead silence in the left side and a very slight hum in the right. With shielding working as it should, we should be on track to get your "beauty" shipped back to you Pabbi by late next week.  Edit: I might take it into Circuit City, with your permission once it is wired to the input connectors to feed a balanced source into it, instead of through the converter. Just a last minute check to ensure everything is as it should be.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Wired up the left channel with shielded wire. Left the right channel unshielded for the A/B on background noise. Lets just call the left one the quiet channel. With no music playing there is dead silence in the left side and a very slight hum in the right. With shielding working as it should, we should be on track to get your "beauty" shipped back to you Pabbi by late next week.  Edit: I might take it into Circuit City, with your permission once it is wired to the input connectors to feed a balanced source into it, instead of through the converter. Just a last minute check to ensure everything is as it should be._

 

I am so not worthy.... but the CC idea is a good one, assuming they don't confiscate it for their own evil purposes... 
	

	
	
		
		

		
		
	


	




 This is really above and beyond, but I hope you are enjoying the time with the amp, where this experience may well benefit others ORR even the coming Super Bijou. I do want Alex to hear it as well for his opinions of what else might can be done (alternate tubes, etc).


----------



## jamess71

I'm excited for you pabbi. 
	

	
	
		
		

		
		
	


	




 I got the Nabu case in and this thing is huge. 
	

	
	
		
		

		
		
	


	




 I didn't really look at the specs before I got it. Anyway I think this is just too much case for my bijou alone. I think I'll save it for when I finally build a B22. What other cases work really good with the Bijou? I would love some recommendations? I'm too busy at work right now to dig through all the old posts and I want to place an order before I leave today. Help. 
	

	
	
		
		

		
		
	


	




 James


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## huskydawg9

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_





 I am so not worthy.... but the CC idea is a good one, assuming they don't confiscate it for their own evil purposes... 
	

	
	
		
		

		
		
	


	




 This is really above and beyond, but I hope you are enjoying the time with the amp, where this experience may well benefit others ORR even the coming Super Bijou. I do want Alex to hear it as well for his opinions of what else might can be done (alternate tubes, etc)._

 

I've never heard anything that was balanced, but am very interested in finding out for myself if it's worth the extra cost. I currently have a Bijou that is modded to allow for tube rolling (currently using 6n1p's) coupled with a 20chip DDDAC. I do have two extra sets of Bijou PC boards so I'm set in that regard... Assuming I acquire a set of balanced headphones, what would I use for the source? Since I have 2 10chip DDDAC boards, could they be modded to support a balanced signal?

 What possessed you to build a balanced version in the first place? Is it that much better?


----------



## fishski13

i placed my order with Par-metal today for a 12 Series 19x12x5.25 chassis - silver anodize, 2 gold alodine dividers, and a vented top. i opted for no vents on the bottom - i will drill these out myself after i have completed the final board lay-out. total damage: $137.50. ouch...hope i like it.

 i received some excellent teflon wire from ebay seller Navships and tubes from Tube Depot today: JJ ECC99, JJ EZ81, and Sovtek 6N1P. still waiting for my tube sockets and transformer from Radio Daze, otherwize my boards are stuffed and ready for the chassis. oh, and i i still need to order a TKD pot from Parts Connexion. i will be using 2 stereo pots when i go balanced instead of a single balanced pot or attenuator (i'm not a fan of attenuators) to help offset any channel balance issues that may arise when trying to match multiple tubes in a balanced design.

 PACE


----------



## pabbi1

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_I've never heard anything that was balanced, but am very interested in finding out for myself if it's worth the extra cost. I currently have a Bijou that is modded to allow for tube rolling (currently using 6n1p's) coupled with a 20chip DDDAC. I do have two extra sets of Bijou PC boards so I'm set in that regard... Assuming I acquire a set of balanced headphones, what would I use for the source? Since I have 2 10chip DDDAC boards, could they be modded to support a balanced signal?

 What possessed you to build a balanced version in the first place? Is it that much better?_

 

There are two distinct things about balanced -channel seperation and speed. It all started for me with the STAX stuff, which is all balanced, and then I invested in sources that were balanced to take advantage of that.

 The other thing that really troubled me about the original Millett was that it would clip really bad with the Senns, at the volumes I require - so, balance a MillettMax at 4x the gain, and, no more clip - ever. Once I got here, SE has never sounded quite right, to me. Edit: Not at all to say that the Bijou would ever have that problem...

 Could be psychoacoustic, or that I am just insane, but I have never heard SE sound better than balanced.... but it is simply a preference I am willing to pay the freight on.

 Regarding source, there is the Joshua Tree OPUS, which is more FUN (forgiving) than my Azur 840c (384k upsampling DAC), but not as precise. I am _hoping_ the Bijou will team a premium balanced tube amp (not hybrid) with a truly nice balanced source. The JT guys also have the Buffalo, which is allegedly vastly superior to OPUS, and would be a place to start evaluating, assuming you aren't wanting to spend > $1500 on a dedicated source.


----------



## fishski13

re: pots

 anyone have any experience with PEC pots? Precision Electronic Components: Potentiometers: MIL Style 2RV7 Features

 KKA series is $32 @ Digikey. looks promising. 

 PACE


----------



## amphead

Those are "good" quality pots. Some would say they are not "excellent". They have a carbon film track where the wiper makes contact, which has the characteristics of a carbon film resistor, "warm" sonically, but not as quiet as metal film. I used some in a Marshall guitar amplifier with great success, but that is a device where even-order harmonic distortion is considered a plus.(jmho)

 Pabbi, I'm not completely out of the woods to get the right channel hum free. Once I finish shielding that channel, I'll know whether or not we should try the ground mod after all. With the longest wire shielded in the right channel, there is still some hum. I'll finish the right channel tomorrow. Edit: hope to have that done before Sunday evening. My nephew is the guitar player in a local band called "The Walking Dead". They are playing in downtown Sacramento on Sunday evening. You can guess who the "roadie/amp tech" is.


----------



## fishski13

thanks.

 PACE


----------



## huskydawg9

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_called Par-Metal re: venting option on a 12-Series and talked with a very helpful Jeanette - "Just fax me a picuture or drawing. As long as it's not too intricate, venting will cost a flat $20". i will be placing my order tomorrow.

 i should have the amp boards stuffed tonight. i've been matching additional resistors and setting them aside for when it comes time to build the second set of boards for balanced. for right now, i'm just excited to hear the Bijou un-balanced.

 PACE_

 


 What if you used the Hammond 17X10X4 case with all boards mounted on top, and the transformer mounted underneath the power supply boards? That way you can get a perf. cover for plenty of cooling. I have a similar setup for the standard version. This way the star ground can be centrally located underneath. With this setup, mine is dead quiet. It seems to me that this could work for the balanced version with the above case.

Attachment 8117

Attachment 8119

Attachment 8121

Attachment 8123

Attachment 8127


----------



## huskydawg9

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_There are two distinct things about balanced -channel seperation and speed. It all started for me with the STAX stuff, which is all balanced, and then I invested in sources that were balanced to take advantage of that.

 The other thing that really troubled me about the original Millett was that it would clip really bad with the Senns, at the volumes I require - so, balance a MillettMax at 4x the gain, and, no more clip - ever. Once I got here, SE has never sounded quite right, to me. Edit: Not at all to say that the Bijou would ever have that problem...

 Could be psychoacoustic, or that I am just insane, but I have never heard SE sound better than balanced.... but it is simply a preference I am willing to pay the freight on.

 Regarding source, there is the Joshua Tree OPUS, which is more FUN (forgiving) than my Azur 840c (384k upsampling DAC), but not as precise. I am _hoping_ the Bijou will team a premium balanced tube amp (not hybrid) with a truly nice balanced source. The JT guys also have the Buffalo, which is allegedly vastly superior to OPUS, and would be a place to start evaluating, assuming you aren't wanting to spend > $1500 on a dedicated source._

 

Thanks for the tips. 
 As luck would have it...the buffalo just went on sale and I picked one up. So I guess I am committed.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, I'm not completely out of the woods to get the right channel hum free. Once I finish shielding that channel, I'll know whether or not we should try the ground mod after all. With the longest wire shielded in the right channel, there is still some hum. I'll finish the right channel tomorrow. Edit: hope to have that done before Sunday evening. My nephew is the guitar player in a local band called "The Walking Dead". They are playing in downtown Sacramento on Sunday evening. You can guess who the "roadie/amp tech" is. _

 

I can understand the 'roadie' gig, as I have been 'doing' guitars since the early 70's - this was once my collection - nothing newer than 1971... mostly Gibson (Lp, Firebird, Junior)... then my basses... 
	

	
	
		
		

		
		
	


	




 Would fixed nfb resistors work just as well, at least for Senns? From the get go, I have worried about hum just due to the space limitations in the Nabu, but let's hope the easy path is successful.


----------



## amphead

That's an amazing collection of guitars, basses and amps!  My collection is down to one Eric Johnson strat and 7 of my custom strats that I used to build. I sold about 20 custom strats before getting out of that industry completely. Although I do the odd guitar repair for friends and local bands. As far as using the fixed resistor NFB option, I would recommend that option only if the ground mod does not work. Adding or increasing NFB results in a darker tone that seems to reduce detail slightly. It very slightly "muffles" noise.


----------



## fishski13

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_What if you used the Hammond 17X10X4 case with all boards mounted on top, and the transformer mounted underneath the power supply boards? That way you can get a perf. cover for plenty of cooling. I have a similar setup for the standard version. This way the star ground can be centrally located underneath. With this setup, mine is dead quiet. It seems to me that this could work for the balanced version with the above case_

 

...because you already used one 
	

	
	
		
		

		
		
	


	




.

 it was my original intent to use the Hammond chassis but then decided to go a different route. i'm probably going to make a window in the front panel and design some trick lighting like i did for a CK2III i built for a friend.






 PACE


----------



## chobint

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_this was once my collection_

 

 : O

  Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_Thanks for the tips. 
 As luck would have it...the buffalo just went on sale and I picked one up_

 

Same here, can't wait to hear the Bijou via a real source.


----------



## amphead

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_...because you already used one 
	

	
	
		
		

		
			





.

 it was my original intent to use the Hammond chassis but then decided to go a different route. i'm probably going to make a window in the front panel and design some trick lighting like i did for a CK2III i built for a friend.






 PACE_

 

Nice work! It will be interesting to see your interpretation of the balanced Bijou.


----------



## amphead

Alex, did the effects of that hurricane manage to get over to Austin? My brother-in-law said there was 3 inches of rain at the convention in Dallas on Saturday.

 Pabbi, I'm leaning toward the ground mod now. The hum is very faint, but lt would be nice to get a completely black background if possible. It's funny or not-so-funny how late night listening brings out all of the detail and in this case any noise. Just don't want you to get the amp back and find that it isn't in tip-top form.


----------



## mwofsi

Forgive me for butting in (too much time on my hands), but there's a couple of unanswered questions over in the Bijou thread at HeadWize.HeadWize: DIY Workshop > Bijou All Tube Futterman Headphone Amplifier - Release

 I thought email notification might not be working perhaps? It's never actually worked for me over there anyways.


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Alex, did the effects of that hurricane manage to get over to Austin? My brother-in-law said there was 3 inches of rain at the convention in Dallas on Saturday.

 Pabbi, I'm leaning toward the ground mod now. The hum is very faint, but lt would be nice to get a completely black background if possible. It's funny or not-so-funny how late night listening brings out all of the detail and in this case any noise. Just don't want you to get the amp back and find that it isn't in tip-top form. _

 

No. Despite the various predictions, we hardly noticed the passing of Ike just to the east of us. Not even significant wind gusts and not a drop of rain. But, just 100 miles east or so, things are very differerent and not so good. I have had my home wiped out by a tornado so I know what it means to lose everything you have. At least, losing all of your material possessions.


----------



## runeight

Quote:


  Originally Posted by *mwofsi* /img/forum/go_quote.gif 
_Forgive me for butting in (too much time on my hands), but there's a couple of unanswered questions over in the Bijou thread at HeadWize.HeadWize: DIY Workshop > Bijou All Tube Futterman Headphone Amplifier - Release

 I thought email notification might not be working perhaps? It's never actually worked for me over there anyways._

 

Thanks mwofsi. I'll go check it out. I stay away from the other forum now because an unamed individual keeps lurking on my threads there to steal ideas.


----------



## koike

OMG pabbi.
 if you ever need to offload any of your basses be sure to let me know 
	

	
	
		
		

		
		
	


	



 just bought a warwick thumb 5 BO but...hey a bassist can never have too many basses


----------



## miky

I got 14.4v across the 1 & 3 wires (unloaded) and 7.1v between the 3 & 4 pins. Any idea if that will be too much (tubes - EZ81 JJ, ECC99 Gold JJ, Amperex Gold Pin 8416)?


----------



## adamus

put it under load and see. the 14.4 counds like it will be too high though. maybe need some resistors in line. 

 anyone know where the best place for these is?


----------



## runeight

I agree. Give it a try and if it's too high we'll figure out where to put the resistors.


----------



## miky

Quote:


 put it under load and see 
 

 You mean made amp o to put some resistors across the 1 & 3 wires? What about 7.1v for EZ81 JJ? It's ok?


----------



## adamus

I mean fire it up, connect it to the heaters and measure the voltage. It wont damage the tubes if you dont have it on for long.


----------



## Listen2this1

Ok I have been following this thread for a while. I think I am going to reward myself and build one over fall break. I have a couple of questions though. How close can I mount the power supply and the amp boards? I have read that they need to be seperated but have not seen a actual distance suggested. If I mount the tubes externally how much heat will be left, and can I mount Q1 and Q2 on the enclosure. Does someone have the spec sheet on the tubes? Like diameter and height.

 I have a enclosure, and I am wanting to place it in this. It was initially fot MHM and I decided to go another way. I will be doing this for a final project in class. I hope that all parts and materials will be in a 3-d model, all the way to the diodes. 

 James


----------



## amphead

6n6p datasheet is here......http://www.lampizator.eu/UPGRADE/RU-6N6P.pdf

 6DJ8 data sheet is here.........
http://lib.store.yahoo.net/lib/thetu...e/JJ-E88CC.pdf


----------



## amphead

Pabbi, I have started the minor surgery of doing the ground mod today. It should eliminate any hum and I was fifty fifty on doing it, because the hum is small. My amplifier refuses to make noise, even without shielding on signal wires and amplifier chassis open/exposed. Edit: although I do have shielding on the input wiring.


----------



## willisv

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_You mean made amp o to put some resistors across the 1 & 3 wires? What about 7.1v for EZ81 JJ? It's ok?_

 

I had about the same (14-14.5V), I used a 5W 4.7R resistor to drop the voltage to 12.16V. The resistor will go inline on one of the wires.


----------



## runeight

Quote:


  Originally Posted by *Listen2this1* /img/forum/go_quote.gif 
_Ok I have been following this thread for a while. I think I am going to reward myself and build one over fall break. I have a couple of questions though. How close can I mount the power supply and the amp boards? I have read that they need to be seperated but have not seen a actual distance suggested. If I mount the tubes externally how much heat will be left, and can I mount Q1 and Q2 on the enclosure. Does someone have the spec sheet on the tubes? Like diameter and height.

 I have a enclosure, and I am wanting to place it in this. It was initially fot MHM and I decided to go another way. I will be doing this for a final project in class. I hope that all parts and materials will be in a 3-d model, all the way to the diodes. 

 James_

 


 Listen2this1, there is no really hard and fast rule on the spacing. But, at least 2-3" apart IMHO. When you choose an enclosure, try to arrange for as much spacing as you can get.

 You can mount the mosfets on the enclosure but remember that they are at high voltage. They need to be insulated, but I would also recommend that you somehow arrange things so that they are not easily accessible to fingers and tools. MHO is that it's better to put them right on the board with their heatsinks. That way you won't be at as much risk of touching their pins and you won't introduce parasitic capacitances into the regulator circuit where it might cause HF oscillations.

 If you mount the tubes through the top there is very little heat left inside. Just a few power resistors and the mosfets.


----------



## amphead

Pabbi, I removed both amp boards which consist of the right channel, and inspected your wiring scheme to ensure the ground mod could work the way it's intended. Looked over the daisy chains for heaters and grounds, and they will work just fine. Reinstalled amp boards, so now to remove PS boards for the "actual" mod. Edit: purchased two 10 watt 100 ohm resistors for the ground. Call it superstition to use those, but they worked well on my amp.


----------



## pabbi1

Watching the surgeon at work... hope you are getting to listen a little on the way - is the sound changing, assumed for the better from burn in?


----------



## amphead

Yes, there has been a steady increase in resolution. It would give me more volume however, if I hooked up both power supplies before listening. One PS set of wires were not hooked up on todays session after wiring up the right channel boards. Late nights take their toll. I was surprised that it even worked! It's alot louder with both power supplies hooked up.  Still working on the ground mod.


----------



## runeight

Say, amphead, do you still have 250V from both regulators?


----------



## amphead

Oops, gulp......373VDC out of both supplies. Edit: chalk it up to tunnel vision to have trusted the PS regulation. This is some design, to have taken a beating like that and still sound/work great!  Edit: it seems to resist my attempts to reduce voltage on both supplies. I have been turning both pots counter-clockwise a few turns, power-up, check, power-down etc......Edit: with both pots turned fully counter-clockwise, one PS is at 350VDC and the other at 335VDC. Alex, do we run in the overvoltage condition safely? It behaves normally otherwise, save the strain it is probably putting on some amp board caps.


----------



## chobint

is that 373vdc loaded or unloaded?


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Oops, gulp......373VDC out of both supplies. Edit: chalk it up to tunnel vision to have trusted the PS regulation. This is some design, to have taken a beating like that and still sound/work great!  Edit: it seems to resist my attempts to reduce voltage on both supplies. I have been turning both pots counter-clockwise a few turns, power-up, check, power-down etc......_

 

WHat is the input voltge to the regulators?


----------



## amphead

I can access pin 3 of the rectifier tube, but access to say the positive terminal of C4 would need to have a wire soldered to the bottom of the board......


----------



## runeight

You can get this voltage by measuring at the exposed lead of R7.


----------



## amphead

Ok, 505VDC and 510VDC on R7 for both supplies.

 YGPM

 Pabbi, did the amp have 250VDC B+ when it left your place? 
 Never mind, I found the answer:
  Quote:


 Powered up, after about 10 minutes still getting a solid 248v on each side (no rebiasing), and all tube heaters came up nicely. Getting the same result - attenuators work, R & L are equally operational, well, at the barely audible level. Oh, and the hum is definitely there - faint, but enough to notice. 
 

Damn! I blew the regulators(at least that's my analysis of the situation) when it ran with one PS hooked up. :holds head down in shame:
 No worries, I'll get those from mouser. I wish I had ordered extras, when I ordered mine. I think I ordered these:FQP4N50


----------



## runeight

These voltages are way, way, way too high. C4-C6 are over voltage and are going to fail. Don't run the amp or ps any more at these voltages. 

 There must be something wrong with the transformer, rectifier combination. What is the AC voltage on the secondaries?


----------



## amphead

Some fantastic news! Sorry guys, just not enough sleep lately. The meter was low on battery power and I didn't notice that. Voltages at R7 ~330VDC, and more importantly voltages at supply outputs around 220VDC, with pots fully counterclockwise. I will dial it in tomorrow, after a good nights sleep.  That meter was giving me a coronary!


----------



## adamus

keeping us on our toes amphead. I was going to suggest the meter, you would have seen caps blowing at those voltages.


----------



## runeight

I gotta agree with adamus amphead. It's always a wild ride when you're driving.


----------



## adamus

my tranformer has arrived. should get this fired up at the weekend. whooop. the Rcore is as big as the ps board.


----------



## amphead

I like to keep everyone updated in a timely manner, but sometimes you just have to keep that information to yourself, until its sanity checked.  Things were going so well, I had to make my own waves. Dialing in the power supplies and then back to the ground mod. Everything is looking very good indeed! Edit: didn't mean to put you through that one Pabbi! Pabbi. Pabbi! Someone give him CPR!


----------



## pabbi1

There is something to reading along in a delayed manner - and not fully understanding the implications.

 That seemed to be a good time to open up the BH... 800v to get my heart started again...


----------



## amphead

Ok, so R9, R10 and C7 have been removed from both PS boards. Tomorrow the grounding resistors get mounted inside the chassis and wired up. Following that the re-installation of the PS boards. Then the audio test for background noise. If that test proves good the last step is to wire the input connectors up to the attenuators, which would complete the overhaul of Pabbi's amp.  It's moving slow as molasses, but we can't afford to take risks/do damage. Pabbi, you can start eating popcorn again. Edit: No more wild rides if I can help it!


----------



## pabbi1

... 
	

	
	
		
		

		
		
	


	




 ... 
	

	
	
		
		

		
		
	


	




 ... 
	

	
	
		
		

		
		
	


	




 ... 
	

	
	
		
		

		
		
	


	




 ... 
	

	
	
		
		

		
		
	


	




 ...


----------



## TimJo




----------



## Dantes

Hi.

 I finished building a bijou this day and i think there is a problem.

 It works very well but i only have 230V at the output's power supply card.
 When i turn the trimpot, P1, the output voltage do not change.

 I don't know where is the probleme. 

 It's strange because the amp works very very well !


----------



## chobint

Hey guys, I'm looking to make a few inexpensive upgrades to my bijou in hopes to improve overall SQ, especially bass response. I am considering upgrading the cathode bypass(amp:C2) and psu:C3 to nichicon kz or panasonic FM, and the psu:C2 and psu:C6 to better plastic caps. I am unfamiliar with amp architechture and don't know how these will affect the sound. Any comments on how any of these proposed upgrades will affect SQ especially with regard to bass response? Thanks


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_Hi.

 I finished building a bijou this day and i think there is a problem.

 It works very well but i only have 230V at the output's power supply card.
 When i turn the trimpot, P1, the output voltage do not change.

 I don't know where is the probleme. 

 It's strange because the amp works very very well !_

 

Hi Dantes. Please measure the voltage at the exposed lead of R7.


----------



## Dantes

the R7 voltage is 239 and the output is 235 after 1 hour of running.


----------



## chobint

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_Hi.

 I finished building a bijou this day and i think there is a problem.

 It works very well but i only have 230V at the output's power supply card.
 When i turn the trimpot, P1, the output voltage do not change.

 I don't know where is the probleme. 

 It's strange because the amp works very very well !_

 

My amp had the same exact problem a few weeks ago. I remedied my problem with fresh regulators and an EZ81 to bring the voltage up. But runeight will probably ask for the voltages at the regulators and then give you the definitive diagnosis 
	

	
	
		
		

		
		
	


	



 edit:lol...i guess runeight already posted


----------



## Dantes

i check some other voltages at the bord and all are lower the those in this picture taken from cavalli's site: http://www.cavalliaudio.com/bijou/im...PSVoltages.gif

 for info, i do not use the hammond and it deliver 255v, not 260.

 I will wait for runeight before crying at the dead of my regulators


----------



## runeight

Dantes, you are saying that the AC voltage on the secondary is 255-0-255V?


----------



## Dantes

yes, it's only 255-0-255.
 But it's because it's a 250-0-250 old transfo, not 260-0-260 as recomended.

 EDIT: the voltage at R8 is only 283V and not 316.

 All seams to work at lower voltage because of the secondary. but P1 did not make the output change.


----------



## runeight

What is the heater voltage. And what is the voltage drop across either R7 or R8 or both? (you can measure both fromone exposed lead to the other).


----------



## amphead

Pabbi, I just finished the listening test after the ground mod and the hum is still there. I notice that the hum slowly fades when the amp is turned off. On my amplifier before the ground mod the buzz/hum immediately stopped when the amplifier was shut off. This leads me to believe that more shielding might help with your amplifier.


----------



## chobint

Have you tried switching the input tubes around? I had a noisy jj 6922 that exhibited the same symptoms. I also found that setting my amp on top of my ungrounded dvd/cd player caused asymetrical noise in the left channel only because it was directly over the dvd xformer. I hope those aren't stupid suggestions, but I wish I had figured that out before rewiring everything.


----------



## adamus

gents,

 my bijou should be fired up tomorrow / sunday.

 question though, i am using the Rcore transformer, unfortunately i dont have a scope so will have to guess to get the two heater secondaries in phase when parallel. will i damage anything if they are out of phase? 

 Also, the safe route would be to tape up all other secondaries, but would anything come to harm if i left the 260's and ct whilst testing the heater secondaries?


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_What is the heater voltage. And what is the voltage drop across either R7 or R8 or both? (you can measure both fromone exposed lead to the other)._

 

I have 48V taken from both exposed lead of R7 and R8.
 The heater is 39V.

 Is'it serious Doctor ?


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_I have 48V taken from both exposed lead of R7 and R8.
 The heater is 39V.

 Is'it serious Doctor ? 
	

	
	
		
		

		
		
	


	


_

 


 48V is reasonable and says that your amp is pulling about 72mA.

 39V volts is the heater bias voltage and it's exactly where it should be.

 What is the AC voltage on the heater secondary?


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_gents,

 my bijou should be fired up tomorrow / sunday.

 question though, i am using the Rcore transformer, unfortunately i dont have a scope so will have to guess to get the two heater secondaries in phase when parallel. will i damage anything if they are out of phase? 

 Also, the safe route would be to tape up all other secondaries, but would anything come to harm if i left the 260's and ct whilst testing the heater secondaries?_

 

You shouldn't need to run the heater secondaries in parallel. IIRC just one of them will supply everything needed for the amp. Leave the other one unused. If you wire them out of phase you will blow a breaker somewhere in your house. 
	

	
	
		
		

		
		
	


	




 You can leave the leads exposed if are absolutely sure that you are never going to touch them and that they are not going to short to each other. If it were me, I would insulate them. It's not hard and it might save you a whole lot of pain or worse.


----------



## adamus

the R core only provides 3 amps per secondary

 1A for the rectifier,
 800mA * 2 for the 6n6p
 300mA *2 for the 6922

 = 3.2A

 will this be ok on one secondary?


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_48V is reasonable and says that your amp is pulling about 72mA.

 39V volts is the heater bias voltage and it's exactly where it should be.

 What is the AC voltage on the heater secondary?_

 

If did not made a misstake, it's 39V too.


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_the R core only provides 3 amps per secondary

 1A for the rectifier,
 800mA * 2 for the 6n6p
 300mA *2 for the 6922

 = 3.2A

 will this be ok on one secondary?_

 

Yes, it probably will. Your transformer is not fully loaded so the heater voltage should be a little high and, hence, the ability for one secondary to be run a little hot. No damage will occur from running 200mA extra. When you hook up the heaters measure the voltage to be sure about it.

 Two secondaries together will make your heater voltage way too high.


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_If did not made a misstake, it's 39V too._

 

Dantes, I think I'm not doing a good job asking my question. 
	

	
	
		
		

		
		
	


	




 Can you measure the AC voltage across the heater secondary winding? It should be between 6-7VAC.


----------



## adamus

cheers, if you were oxford i would buy you a beer.


----------



## Dantes

I have 7.1v.
 seems to be good. A little too high peraps.


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_I have 7.1v.
 seems to be good. A little too high peraps._

 

OK. This heater voltage means that your EZ80 is working hot enough.

 Your voltage at C6 (R8) says way too low if your transformer AC is 255V.

 First thing to do is to try an EZ81 in place of the EZ80. Once we get C6's voltage over 300V we can fix other problems that may or may not be there.

 BTW, the heater voltage is too high. At most it should be 6.8V. But we can fix this later. The EZ81 will drop this voltage too.


----------



## Dantes

ok, i will buy an EZ81 as soon aas possible.

 Thanks a lot 
	

	
	
		
		

		
		
	


	





 But i continue to not understand why, when i start the power suply with the charge resistor i could set the output voltage at 250V withe pot.
 After fully install all wires, the pot do not work.


----------



## runeight

OH. Well let's fix this while you wait for the EZ81. 
	

	
	
		
		

		
			





 Remove the amps from the B+ and put the 100k resistor back.

 What is the voltage at R7 and R8?


----------



## Dantes

so... with the 100K resistor, the pot works .... uncredible ! 
	

	
	
		
		

		
		
	


	




 So, R7 = 319, R8 = 332


----------



## runeight

So, it's possible that your mosfets are not dead!!

 Now we just have to wait until you get the EZ81.


----------



## runeight

Say, Dantes, are you sure about those voltages at R7 and R8? Because if they are correct, you are drawing almost 20mA with nothing connected to the amp.

 Edit: What are the values of R7 and R8?


----------



## Dantes

i check them again, results are different...
 i will check the battery of my Voltmeter... 
 at R7 = 307V
 at R8= 322V.


----------



## runeight

Those values are close enough. Are you sure about the voltages at R7 and R8? If you are, then we must do more troubleshooting.

 Is there anything else connected to the PS besides the 100k resistor?


----------



## Dantes

To test i only remove the cable linke to the 250V connector of the supply and replace it by the resistor.
 So the 2 amp boards are connected to all there cables.


----------



## amphead

Pabbi, the next step is for me to rewire the amp in some areas with tightly twisted wire. And there are a couple of signal wires that need shielding. After doing that I will listen/test again. Another thing to try after that is to remove the transformer from the chassis and with it running about 12" from the chassis, see what effect that has. Running in close quarters may have something to do with it.


----------



## pabbi1

Here is to hoping that isn't the case, as one box is a crucial design decision... how bad is the hum? Only there in the absence of signal, or always noticeable? Mayhaps to topmount the trafo?

 IFF the Nabu is just too tight, I do have another enclosure which is larger (17"x17"), though the same height. Not my preferred course of action, but one option. It is a steel server case that I used for the Blue Hawaii, but, perhaps it would just be a tradeoff with more space?

 I am really feeling bad that this is taking you further afield (and taking G_d knows how much of your time), albeit for the greater good.


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_To test i only remove the cable linke to the 250V connector of the supply and replace it by the resistor.
 So the 2 amp boards are connected to all there cables._

 

OK. This should work and means that the PS is not connected to anything but the resistor. And this means that if your measurements at R7 and R8 are correct, there is a problem in the regulator. Could you please verify those voltages with just the 100k resistor loading the PS.


----------



## amphead

The hum is the same slight background that you heard before, and seems to be in the right channel very slightly. Not noticeable while music is playing. I'm certainly leaning towards the larger 17 x 17. The way the wiring is strictly confined between the amp boards is a concern. I am going to try some more shielding. My brother-in-law(engineer) says that it probably isn't heater wiring, but a ground/shielding problem. He says that based on the fact that the hum slowly goes away when it is powered down, instead of instantly going away. Edit: putting the time on the amplifier isn't a problem, just wanting to be successful with the final configuration that works for a balanced Bijou. Edit: There might be an aluminum enclosure at the local surplus metals store here.


----------



## amphead

While on the one hand, it may be possible to build a quiet balanced Bijou in the NABU chassis, I think that with ample room it would be like shooting fish in a barrel to do one successfully. This hinges of coarse on whether or not the 270HX is up to the task of powering 2 PS boards and 4 amp boards quietly, which it should be. I don't think there would be a problem, having your amp wired like mine. While the hum is small, there is just enough of it to be unacceptable to your ears, my ears and most members of the forum.


----------



## adamus

We have life!!!!! 

 ****ty backward volume control life (dont ask.......) but life never the less. 


 First issue is a noise in both channels. It gets louder with volume. it isnt a hum, its quite high pitch, a bit like white noise with a slight wine superimposed. Could this be tubes breaking in? 

 Second issue is my F'ing backwards pot. Note to self, take more breaks.


----------



## adamus

scratch that, its completely silent.

 Its noise from the usb alien dac. Any ideas why only the bijou would pick this up, the soha is dead silent?


----------



## runeight

What do you mean when you say "pick it up"? Is the noise inherent in the signal coming from the dac? Or is it a result of the interconnects?


----------



## adamus

well its the only amp i have that lets me hear the noise on the usb line (e.g scrolling on a web page causes noise). 

 plug my soha + jisbos in and its perfect. 

 Must be a grounding issue. Should the signal ground be star grounded?


----------



## runeight

Almost certainly a grounding issue.

 Are the input jacks grounded to each board at the In G connection?


----------



## adamus

yes, signal ground goes to ground on the pot, and then to signal ground on boards.


----------



## runeight

Is the amp in a case? Is the amp star g connected to the case? And is the case connected to the line (mains) ground?

 Just doing some detective work on you.


----------



## adamus

star g connected to IEC earth, IEC earth connected to chassis. Star G bolt on exposed chassis. 

 By the way, this thing sounds superb, the space it gives is unreal.


----------



## runeight

Hmmm. I don't have a good next step. I don't use dacs and don't have enough experience with the problems that they cause. Can anyone else offer a thought about what this problem might be?

  Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_By the way, this thing sounds superb, the space it gives is unreal._

 

That was my reaction when I first heard my proto version. It was what convinced me that I had to find a way to create a simple Bijou build to make available. It really is a gem. Wait until you get some hours.


----------



## adamus

is it normal to have very little travel in the volume pot? the gain seems very high with no NFB.


----------



## runeight

Yes, it's normal. The gain with no NFB is about 25X. With a source that is putting out 1V or more, there is little that can be done.

 The is one of the reasons for the NFB. With the NFB pot, even when the NFB is turned to minimum, there is still enough NFB to reduce the gain considerably.


----------



## runeight

BTW, you can cut the gain in half by removing the cathode bypass cap on the first stage. Don't know what will happen to the audio.


----------



## adamus

The noise i hear has probably always been there, my soha is really low gain (attenuated jisbos). Maybe its juts the high gain thats making it apparant. I will try my other dac and report back.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_While on the one hand, it may be possible to build a quiet balanced Bijou in the NABU chassis, I think that with ample room it would be like shooting fish in a barrel to do one successfully. This hinges of coarse on whether or not the 270HX is up to the task of powering 2 PS boards and 4 amp boards quietly, which it should be. I don't think there would be a problem, having your amp wired like mine. While the hum is small, there is just enough of it to be unacceptable to your ears, my ears and most members of the forum._

 

Well, the drilling and layout work seems a lot to offload, not to mention remounting IEC, pots, and jacks. Then, the ventilation, and whether to top mount the tranny... <sigh>. At least I have plenty of wire for all the required rewiring. IFF it seems like a prudent way to go, I can have a new case there by Wednesday, but feel like that is a mess I should be cleaning up. 

 With your investment in this to date, I am all for you seeing this to completion. Besides, I have another box to send you, anyway, but this one is for keeping...


----------



## huskydawg9

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, I just finished the listening test after the ground mod and the hum is still there. I notice that the hum slowly fades when the amp is turned off. On my amplifier before the ground mod the buzz/hum immediately stopped when the amplifier was shut off. This leads me to believe that more shielding might help with your amplifier._

 


 I am by no means an expert. But I built my Bijou with a steel Hammond case. Boards mounted on top, star ground dead center underneath the chassis. I have a thick sheet of plastic on top of the chassis to shield the transformer. There is absolutely no noise or hum. I have to believe that a balanced version built in this manner would yield similar results. Just a thought. I'm seriously thinking of pursuing a balanced version further, as I have two more sets of pc boards...


----------



## huskydawg9

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Hey guys, I'm looking to make a few inexpensive upgrades to my bijou in hopes to improve overall SQ, especially bass response. I am considering upgrading the cathode bypass(amp:C2) and psu:C3 to nichicon kz or panasonic FM, and the psu:C2 and psu:C6 to better plastic caps. I am unfamiliar with amp architechture and don't know how these will affect the sound. Any comments on how any of these proposed upgrades will affect SQ especially with regard to bass response? Thanks_

 


 I used Clarity caps 1.0uF for the cathode bypass, and am very pleased with their results. Reasonably priced also.
 I might add...if you haven't done it already... mod it to use 6N1P tubes (see Cavalliaudio website, bijou tweeks section) Unless you want to spend big bucks for premium 6922's, this is a very cheap upgrade and you will love it. The 6H30's are an improvement also, but the 6H1N-BN RUSSIAN VALVE's (6N1P) that I am using blow them away.


----------



## fishski13

just finished soldering the tube sockets and C6 (Sonicap 0.47 uF). i used SIP sockets for the RLED and R2 - i will be experimenting with some trick LED lighting, and will no doubt want to try rolling more tubes. i also soldered R3,5,6,7 on the bottom in case i want to try Regal's Mod.

 hopefully my enclosure will arrive this week. i'll probably place an order for a PEC pot on Mon. from Digikey. going balanced will have to wait a month - i just bought a pair of HD650 that sound absolutely stonking via my M3.

 i may get the guts to "fire" this sucka up sans enclosure. i'm going to try playing with FPE tonight.











 PACE


----------



## amphead

fishski13, looking very good!

 Pabbi, let's pull the trigger on doing the 17x17. I only have your budget in mind with any of this. And the mounting of parts into the new chassis, with new wiring is going to proceed fairly quickly. The only thing that could slow it down with new chassis would be if there was a borderline/bad component installed right now. And I don't believe that is the problem. Thanks for peaking my interest in the "mystery" box.


----------



## adamus

I have put a couple of hours on the bijou now. 

 the soundstage is just so defined and massive. Its like each instrument / voice has its own space in my head. This is the standout feature for me. If i want to listen to the prodigy: diesel power, then the grunt of the soha and jisbos may be favorable, but anything else, the bijou just creates a holograph to explore. 

 It is also the first amp i struggle to analyse, the music just takes over. normally i am hyper critical and search for optimising. I may just be settled with this (....although there is the option of tube rolling!!!)


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_fishski13, looking very good!_

 


 thanks.

 anybody have tips on how to post/show FPE designs with a PC 'puter?


----------



## naamanf

Print it to a file.


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_OK. This should work and means that the PS is not connected to anything but the resistor. And this means that if your measurements at R7 and R8 are correct, there is a problem in the regulator. Could you please verify those voltages with just the 100k resistor loading the PS._

 


 I have test with only the power suply board and the 100K resistor.
 Same results: R7 : 309V and R8 : 321V.


 EDIT:

 I re check all my wires and rewire all the amp and now the pot works.... 
	

	
	
		
		

		
			




 But i only have 240V max at the power supply output.


----------



## fishski13

we'll see if this works. nope...


----------



## fishski13

let's try again. he shoots and he scores???


----------



## JamesL

That thing looks great, but oh man.. 21 x 6"? That thing's gonna be huge!
 Are you building a balanced bijou?.. the two holes in the middle look like they were made for XLR's.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_we'll see if this works. nope..._

 

Edit: Never mind. I missed one of your posts.


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_I have test with only the power suply board and the 100K resistor.
 Same results: R7 : 309V and R8 : 321V.


 EDIT:

 I re check all my wires and rewire all the amp and now the pot works.... 
	

	
	
		
		

		
		
	


	



 But i only have 240V max at the power supply output._

 

Dantes, if you are certain that these are the measurments on R7 and R8 when nothing is connected but the 100k resistor, then there is an internal problem in the PS. It could be that the mosfets are toasted.

 However, since the trimpot seems to work, this says that they working. So your measurements are inconsistent.

 In order to get 250V from the regulator it must have at least 260V at R7. You are not getting this with your transformer and EZ80. The EZ81 will help to increase this voltage, but we have to find out why your PS is drawing 20mA when it is not loaded.

 Please check it over carefully and make sure that all of the parts values are correct.


----------



## fishski13

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_That thing looks great, but oh man.. 21 x 6"? That thing's gonna be huge!
 Are you building a balanced bijou?.. the two holes in the middle look like they were made for XLR's._

 

balanced yes. the 2 larger diameter holes are for Neutrik XLR/phono combo jacks, and the 2 outer, smaller holes are for the stereo pots. the rectangle on the left is for a rocker switch, probably slightly recessed. i'm going for a retro 80s muscle amp look, faceplate handles as well. cost is $89!!! plus an acrylic sheet from the hardware store.

 and we have PS lift off...






 PACE


----------



## adamus

why the connection between heaters and star G at this point.... did i forget something when i finished mine??


----------



## fishski13

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_why the connection between heaters and star G at this point.... did i forget something when i finished mine??_

 

i'm going with Amphead's Mod, grounding the heater secondaries with a pair of1/2W 100R in series to star ground. as far as i have gleaned from this thread, there is no downside with removing the heaters from the bias chain. R9,10 and C7 have been left out of the board.

 PACE


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_why the connection between heaters and star G at this point.... did i forget something when i finished mine??_

 

adamus, if you've installed all of the components on the PS board then your heaters are properly biased and you don't need to do anything else. Particularly if you're not hearing any noise from the amp.

 The amphead mod is available in case someone is experiencing unexplained noise that might be coming from the heaters. You can find this mod on the website, bit I think it's best to leave the amp as is if it's not causing you any problems.


----------



## fishski13

heaters are working!


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_fishski13, looking very good!

 Pabbi, let's pull the trigger on doing the 17x17. I only have your budget in mind with any of this. And the mounting of parts into the new chassis, with new wiring is going to proceed fairly quickly. The only thing that could slow it down with new chassis would be if there was a borderline/bad component installed right now. And I don't believe that is the problem. Thanks for peaking my interest in the "mystery" box. _

 

It's actually all in one box, and will go out first thing tomorrow, where you should see it all Wednesday. We won't clutter this thread with the 'extra' contents, but other than the case and wire, all will be yours to do with as you see fit - it should make a nice play pretty, well with a bit of cleanup - or, parts as you should need them. 

 The case has a couple of aluminum plates screwed to the bottom, which are just spare material, and I hated to just throw it away - use it as you see fit. If nothing else, I can machine it into a trans cover, should that need to be cut out of the top plate (I anticipate it will, but can certainly do that later). If it makes sense to mount the tranny on the cover, that would be acceptable as well. I definitely need to drill the top plate for ventilation, but was going to wait until the boards were mounted to punch the holes, especially for venting the tubes.

 Do feel free to proceed any way you feel necessary.

 I am traveling until late Wednesday or mid-day Thursday, but will respond asap then. 

 And, thank you - this is all really above and beyond - I feel luckier than KRMathis...


----------



## amphead

Yes, Krmathis is a lucky Head-fier indeed. Although that wasn't his fault, it was mine.  Looking forward to getting your amplifier laid out in the new roomy chassis, where each board has its own master bedroom and walk-in closet. The boards are moving from the condominium to the mansion.  Have a nice road trip! Edit: My wife is waiting on a digital camera that she was awarded as a longtime employee of a health-care company. I would like to post pics of your new amp coming together when that comes.


----------



## fishski13

all this talk about needing a larger enclosure is making me a bit nervous. the Par-Metal 12-Series enclosure i ordered is 17x11.5x4.9. i will be using 2 alodined dividers as well. 

 i am by no means an expert, but maybe the hum is from a taxed tranny with core saturation releasing magnetic flux/currents into the nearby circuits. how are you wiring the 270HX?

 PACE


----------



## fishski13

...and was there any noise when powering only 2 boards unbalanced?


----------



## amphead

I can't rule out the fact that we are powering twice the number of boards from the 270HX, which might be creating hum, however putting everything in the spacious chassis will help me to immediately know. This will be wired the same way that my amplifier is. I think you will be better off with the 11.5" versus Pabbi's 10" for that dimension. An inch and a half is alot better. Pay close attention to the layout of the amp boards in particular to give some wiring room between boards, because that has limited the NABU chassis's usefulness. What transformer are you using, I forgot? Edit: actually I can rule out whether or not the 270HX is overtaxed. If there is still hum I will borrow the transformer in my amplifier and see what it does with separate xformers.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i am by no means an expert, but maybe the hum is from a taxed tranny with core saturation releasing magnetic flux/currents into the nearby circuits. how are you wiring the 270HX?

 PACE_

 

This is a good point fishski13 and can be a problem. In this case the 270HX has a 200mA HV secondary and the amp will only draw about 140mA (or less). The heater secondary is 6A and the amp, depending on the rectifier, will draw a little more or a little less.

 However, the transformer also has a 5V/3A winding which wil be unused. So even if the 6.3V secondary is overtaxed a bit, there is still plenty of iron left.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I can't rule out the fact that we are powering twice the number of boards from the 270HX, which might be creating hum, however putting everything in the spacious chassis will help me to immediately know. This will be wired the same way that my amplifier is. I think you will be better off with the 11.5" versus Pabbi's 10" for that dimension. An inch and a half is alot better. Pay close attention to the layout of the amp boards in particular to give some wiring room between boards, because that has limited the NABU chassis's usefulness. What transformer are you using, I forgot? Edit: actually I can rule out whether or not the 270HX is overtaxed. If there is still hum I will borrow the transformer in my amplifier and see what it does with separate xformers._

 

i'm using a 370 DAZ, horizontal mount. i will need another for balanced - i haven't decided if should go with another DAZ, or a vertical mount DAX. i want to minimize transformer coupling as much as possible, and will be using an alodine divider to isolate from the PS boards.

 i've reworked yet another layout. i'm finding out that an 1.5" is expensive real estate after running the heater wiring sans chassis the other night.

 PACE


----------



## amphead

Based on the NABU chassis and Pabbi's layout, you will be able to separate the two transformers by about 5 inches, if you locate them at the 2 corners on one end of the chassis. It will mean running a little longer xformer primary wire for one of them, but that shouldn't be noisy if they are tightly twisted.


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Dantes, if you are certain that these are the measurments on R7 and R8 when nothing is connected but the 100k resistor, then there is an internal problem in the PS. It could be that the mosfets are toasted.

 However, since the trimpot seems to work, this says that they working. So your measurements are inconsistent.

 In order to get 250V from the regulator it must have at least 260V at R7. You are not getting this with your transformer and EZ80. The EZ81 will help to increase this voltage, but we have to find out why your PS is drawing 20mA when it is not loaded.

 Please check it over carefully and make sure that all of the parts values are correct._

 

Yes i'am sure of the my measurement.
 I bought the Glassjar audio kit to make my bijou.
 I think all parts are good.
 I will recheck all parts when i could, time is short this days... 
	

	
	
		
		

		
			




 Peraps a part is broken. I made a mistake on wirering the transformer and i broke one EZ80.


----------



## randytsuch

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i'm using a 370 DAZ, horizontal mount. i will need another for balanced - i haven't decided if should go with another DAZ, or a vertical mount DAX. i want to minimize transformer coupling as much as possible, and will be using an alodine divider to isolate from the PS boards.
_

 

Is that an aluminum alodine divider?
 Al will give you no magnetic shielding, you need to use mumetal, or something with iron in it for magnetic shielding.

 I'm working on a project, and was going to use the ti shield that percy sells to shield my transformers from the rest of the box. It's kind of expensive, but you don't need that much.

 Randy


----------



## fishski13

Quote:


  Originally Posted by *randytsuch* /img/forum/go_quote.gif 
_Is that an aluminum alodine divider?
 Al will give you no magnetic shielding, you need to use mumetal, or something with iron in it for magnetic shielding.

 I'm working on a project, and was going to use the ti shield that percy sells to shield my transformers from the rest of the box. It's kind of expensive, but you don't need that much.

 Randy_

 

thanks for the heads up on the Ti shield. i was considering trying something from here, Magnetic Field Shielding Materials, but since i already need to place an order from Percy...

 PACE


----------



## adamus

It appears i do have a bit of grounding issue with my bijou. It i turn NFB up (which dcreases the volume) the noise diminishes to the point its completely silent and volume is turned up. (this is with the alien dac). 

 If i plug in the Ipod, a noise is barely audible, and when i touch the pot its completely silent. 

 I have isolated jacks (checked with dmm) 
 shielded transformer to IEC earth to star ground. 
 IEC is filtered unit so is grounded to case at that point too.
 Star ground is bolt and nut through the chassis. 
 everything is connected as shown on wiring diagram. 
 Noise isnt apparant on Soha + jisbos even at max volume. 

 any ideas?


----------



## runeight

Have you tried grounding the cases of the vol and nfb pots?


----------



## adamus

just tried it with clips, get rid of the tiny amount of hum with the ipod (so so small you have to have nfb min and volume max). 

 Doesnt touch the dac output. 

 I am going to move the amp away from my pc and see what happens.


----------



## adamus

ok, just tried it on my bedroom dac (fed from an airport express) and its perfect (tiniest bit of hum which goes away when i ground the pot)


----------



## adamus

Ok,

 Forget absolutely everything i have said. 

 My usb cable has been acting as an antenna. It was signal noise.

 Itried a different cable and things got better. 

 moved to the back ports (away from hard disks etc) and we have silence

 Runeight - Thanks for the grounding tip on the pots, its eeked out the last bit of blackness. 

 Cheers

 adam.


----------



## amphead

Congrats Adamus, enjoy the music!


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Ok,

 Forget absolutely everything i have said. 

 My usb cable has been acting as an antenna. It was signal noise.

 Itried a different cable and things got better. 

 moved to the back ports (away from hard disks etc) and we have silence

 Runeight - Thanks for the grounding tip on the pots, its eeked out the last bit of blackness. 

 Cheers

 adam._

 

Great!!! Now after more listening, tell us if you have any further thoughts on the amp.


----------



## fishski13

just fired up the Bijou (very carefully i might add). i can't wait to get this amp in an enclosure. after 10 min or so of listening to Air, my sacrifical earbuds have never sounded this good. 
	

	
	
		
		

		
		
	


	




 PACE


----------



## TimmyMac

How hot does the 270DAX normally get with this design? I'm running EZ80, 6N6P, and 6922 tubes and trafo all surface mounted and an unvented case, and the whole top plate is pretty warm and the trafo is too hot to grab for more than 10seconds or so. Is this normal or do I need to vent the case to help cool the MOSFETs inside? I'm assuming the transformer is fine at 50 or 60 degrees C or whatever it is...


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_just fired up the Bijou (very carefully i might add). i can't wait to get this amp in an enclosure. after 10 min or so of listening to Air, my sacrifical earbuds have never sounded this good. 
	

	
	
		
		

		
		
	


	




 PACE_


----------



## runeight

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_How hot does the 270DAX normally get with this design? I'm running EZ80, 6N6P, and 6922 tubes and trafo all surface mounted and an unvented case, and the whole top plate is pretty warm and the trafo is too hot to grab for more than 10seconds or so. Is this normal or do I need to vent the case to help cool the MOSFETs inside? I'm assuming the transformer is fine at 50 or 60 degrees C or whatever it is..._

 

This is normal. The transformer is perfectly alright if you can touch it for 10s.

 It's hard to say exactly about the fets, but they are 150C devices. They should be ok.

 Do you have any ventilation at all?


----------



## TimmyMac

No ventilation. The case is 2 steel plates with a frame of wood. The bottom plate is barely warm which leads me to believe the air inside is ok, and it's just heat from the tubes and trafo warming up the top plate.

 Also, I've got a bit of noise in one channel that moves to the other channel when I swap 6922's. Should I just drop $20 or whatever for a new one? I'm using the JAN Phillips ones supplied with Jeff's kit.


----------



## runeight

MHO would be that you should put some ventilation into the top. This will preserve component life, especially the electrolytics which degrade much more quickly when they get too hot.

 The first thing to check is to be sure the the pins are clean of any oxidation that will prevent good contact with the socket.

 If the pins are clean and the noise really does follow the tube, then it probably needs replacing. How long has it been in service? Sometimes they quiet down after about 50 hours when the getters have taken out all of the junk and the cathodes are really formed. Sometimes they don't because the spot welds are bad or the cathode was just not constructed properly.


----------



## TimmyMac

I'd say maybe 150-200 hours on the tubes. I could try leaving the amp on for a few days straight to see what that does.


----------



## runeight

No, that's not likely to help. They been running long enough. Try cleaning the pins.


----------



## adamus

chaps, my first impressions can be seen here:

http://www.head-fi.org/forums/f5/rev...iy-amp-365749/

 Again - Runeight, cant thankyou enough for all the contribution.


----------



## amphead

fishski13, it really is a spacious sound isn't it. My guess is you will be risking more than earbuds soon.


----------



## amphead

Pabbi, the eagle has landed. The new chassis arrived yesterday, and will make the balanced configuration a whole lot easier. Even though I immediately could see the best layout option, the elevator engineer brother-in-law will get to put in his 2 cents tonight, when I go there for dinner. Thank you very much for the mystery box. Well I guess I'll be Geraldo Rivera and reveal your generosity to the members here. It's a balanced Starving Student. Can't wait to get your amplifier into it's new configuration.


----------



## huskydawg9

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_You could always do a bit of ground work and figure it out for yourself._

 

I see you are in Iraq..you know M. Soja? I work with him back in the states.


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_Yes i'am sure of the my measurement.
 I bought the Glassjar audio kit to make my bijou.
 I think all parts are good.
 I will recheck all parts when i could, time is short this days... 
	

	
	
		
		

		
		
	


	



 Peraps a part is broken. I made a mistake on wirering the transformer and i broke one EZ80._

 

Dantes, how is your amp doing?


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_chaps, my first impressions can be seen here:

http://www.head-fi.org/forums/f5/rev...iy-amp-365749/

 Again - Runeight, cant thankyou enough for all the contribution._

 

You're welcome. 
	

	
	
		
		

		
			





 Thanks for taking time to build it.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, the eagle has landed. The new chassis arrived yesterday, and will make the balanced configuration a whole lot easier. Even though I immediately could see the best layout option, the elevator engineer brother-in-law will get to put in his 2 cents tonight, when I go there for dinner. Thank you very much for the mystery box. Well I guess I'll be Geraldo Rivera and reveal your generosity to the members here. It's a balanced Starving Student. Can't wait to get your amplifier into it's new configuration. _

 

Always look the gift horse in the mouth... 

 That said, there are also enough other parts to build another one or two, save the tubes and warts. It was really addition by subtraction for me (one less distraction) and needs some attenuation as well as modding - but, you will have the only one in the world - should you so desire to keep it that way. It also got all those parts away to keep me from considering yet another build. 
	

	
	
		
		

		
		
	


	




 Here's to hoping the new case lays out as pretty as planned, and kills the nasty hum of the Nabu..


----------



## chobint

oh my...well disabling NFB sure makes a night and day difference with high ohm headphones 
	

	
	
		
		

		
		
	


	










 I wanted to toss my week old hd650's in the trash until about an hour ago


----------



## runeight

If you're sure you'll be listening with high Z phones, no NFB is the better option.


----------



## chobint

indeed, the increased quantity/impact of both bass and trebel are very pleasing, but now my bijou is perma tuned into a local radio station...lol. Time to bust out the shieled mic wire.


----------



## adamus

when i had a slightly noisey usb signal, no nfb made it a lot worse - I could dial it out with NFB. 

 My review shows my preference for very little NFB, but just a tiny bit seems to give it a slightly warmer presenation.


----------



## amphead

Yes, I think both running without NFB, or with minimal NFB are the best options. It depends on your phones and personal taste.

 Pabbi, I have mounted the xformer into the new chassis, and tomorrow I will cut an opening for the power switch/iec, and install it. We are on our way. Edit: out of superstition, the transformer is mounted with iron facing the boards instead of the bell end.


----------



## fishski13

chassis arrived today, right on time. i also pre-drilled all holes on the bottom plate for a balanced build. 8 hrs of work...see the attachments below. constructive criticism appreciated - this is my first tube amp. 

 listened with the K701 and iPod via headphone jack (i don't have a LOD) for a short bit.


 WOW!
	

	
	
		
		

		
		
	


	













 i can't wait until i can get this boxed up for some extended plays. i will post more then about the sound. but as it stands now, i've never heard music sound like this before - it's alive and breathing. crazy tone detail as well. 
	

	
	
		
		

		
		
	


	




 PACE


----------



## huskydawg9

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_chassis arrived today, right on time. i also pre-drilled all holes on the bottom plate for a balanced build. 8 hrs of work...see the attachments below. constructive criticism appreciated - this is my first tube amp. 


 PACE_

 

Nice job. There might not be enough holes in the lid, as it really kicks out the heat with extended play.


----------



## JamesL

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_Nice job. There might not be enough holes in the lid, as it really kicks out the heat with extended play._

 

I think the lid would fall apart if it had any more ventilation holes..


----------



## huskydawg9

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_I think the lid would fall apart if it had any more ventilation holes.. 
	

	
	
		
		

		
		
	


	


_

 

What I meant was when you go balanced and have 2 trannys and 3 more boards in there...you may have to run with the top off.


----------



## adamus

I think it will stuggle with any more than mesh. there is a lot of heat generated.

 Edit - Actually, you may be fine with that top you have, looks very well ventilated. Maybe some larger cutouts in the base would help though. 6n6p's kick out a lot of heat.


----------



## chobint

looks good fishski13. The wiring looks exceptionally tidy, what are those little plastic wiring guide thingies you are using?


----------



## adamus

gents, my top plate is coming on well. I am using a couple fo deconstructed valve protection frames ad decorative washers. Just need to find some nice stainless hex bolts. 

 Heres a sneak preview


----------



## runeight

Gents, these new amps of yours all look very nice. They harken back to the days when tubes were king.


----------



## pabbi1

Very nice, gentlemen. But, along with several other designers (Pete Millett, KG, etc) mayhaps we are proving tubes are still the king, albeit in smaller kingdoms.

 I cannot wait to start getting these amps out to meets to shootout with some of these other designs, and get to the crux - why are these kingdoms smaller, and, maybe, they will grow quite a bit.


----------



## runeight

pabbi1, after you get your balanced Bijou in working order, you'll have to build a balanced SOHA II.


----------



## pabbi1

Well, I was thinking more Stacker, or whatever it is you are doing with the 'Super Bijou'... but, seriously, we really need you looking at electrostatics. There is someone else in Austin that could use a little collaboration, and, well, the tube could be a 6s4... though Russian (6nxp) tubes would be a real preference - oh, and all are balanced by default... 

 Though, I have been eying SOHAII - I do need to build something for my brother in Afghanastan (civvy contractor with the JarHeads), so that is my 2nd favorite read these days.

 Doing any transformer coupled designs?


----------



## TimmyMac

So I scored a Mullard EZ81 for a decent price off ebay... and maybe this is just placebo but it seems like the detail in the highs and upper mids just opened right up! Does the extra 15 volts or so on the B+ make that much difference?

 I've got Electro-harmonix 6922's coming to replace my horribly noisy and microphonic JAN Philips tube in the left channel.


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Well, I was thinking more Stacker, or whatever it is you are doing with the 'Super Bijou'... but, seriously, we really need you looking at electrostatics. There is someone else in Austin that could use a little collaboration, and, well, the tube could be a 6s4... though Russian (6nxp) tubes would be a real preference - oh, and all are balanced by default... 

 Though, I have been eying SOHAII - I do need to build something for my brother in Afghanastan (civvy contractor with the JarHeads), so that is my 2nd favorite read these days.

 Doing any transformer coupled designs?_

 

Electrostatics? I thought that there were top of the line diy amps out there already. But I'm listening. What did you have in mind?

 Transformer coupled headphone amps or power amps? 
	

	
	
		
		

		
		
	


	




 Now if you're looking for some very cool power amps I have two of them up my sleeve that I'm just waiting to get around to.


----------



## runeight

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_So I scored a Mullard EZ81 for a decent price off ebay... and maybe this is just placebo but it seems like the detail in the highs and upper mids just opened right up! Does the extra 15 volts or so on the B+ make that much difference?

 I've got Electro-harmonix 6922's coming to replace my horribly noisy and microphonic JAN Philips tube in the left channel._

 

Many diyers believe that certain changes in the ps make an audio difference. There are some that definitely do because they enable better dynamic operating conditions for the devices. In this case, it's hard for me to know. The pass mosfets might be a little happier with a few more volts on them, but they'll still be regulating to 250V. Thus, the tubes might not see much difference. OTOH, the rectifier is not working as hard. So, I guess I really don't know. At this point, after having designed so many amps that are in wide usage, I just think that everyone hears differently. And that some folks can hear very small effects.


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Electrostatics? I thought that there were top of the line diy amps out there already. But I'm listening. What did you have in mind?

 Transformer coupled headphone amps or power amps? 
	

	
	
		
		

		
		
	


	




 Now if you're looking for some very cool power amps I have two of them up my sleeve that I'm just waiting to get around to._

 

HP all the way... a la Pate's 307a for dynamics, though I think the Bijou will get most of the way there. 

 On the electrostatic side, there is a real problem on the DIY amps. KG has given us the KGSS and BH, but both depend on some obsoleted parts (2sk389, etc), and are really difficult to build. Some commercial designs are older generation, some based on Stax DIY layouts, and with some problems where NOT implemented correctly. But, they all also depend on NOS harder than ever tubes, and new designs, with different (read: more available, like 6s4, or Russian) tubes are one answer.

 Just if you happen to be pounding the rubble on the dynamic front, electrostatic DIY can use a boost.


----------



## runeight

That is a mighty expensive headphone amplifier. Although I have no possible way to know, I wonder if a less expensive amp can do just as well?

 I see on the electrostatics. I thought that the BH had pretty much solved the problem for everyone. How much interest would there be in a new amplifier, maybe a hyrid one? I have, you see, already thought about how to do one of these too.


----------



## naamanf

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_That is a mighty expensive headphone amplifier. Although I have no possible way to know, I wonder if a less expensive amp can do just as well?

 I see on the electrostatics. I thought that the BH had pretty much solved the problem for everyone. How much interest would there be in a new amplifier, maybe a hyrid one? I have, you see, already thought about how to do one of these too. 
	

	
	
		
		

		
		
	


	


_

 

I think there would be a fair amount of interest in a new 'stat amp, especially with the gaining popularity in 'stats. Count me in if you decide to go that route.


----------



## pabbi1

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_That is a mighty expensive headphone amplifier. Although I have no possible way to know, I wonder if a less expensive amp can do just as well?

 I see on the electrostatics. I thought that the BH had pretty much solved the problem for everyone. How much interest would there be in a new amplifier, maybe a hyrid one? I have, you see, already thought about how to do one of these too. 
	

	
	
		
		

		
		
	


	


_

 

There are collaborators in Austin that will find this encouraging... maybe a couple of email would be in order. Since there are still excellent production electrostatic phones, and the Stax amps are lacking, there is a LOT of demand for the upper end, ESPECIALLY DIY.


----------



## runeight

OK. Let me know who the Austinites are. I might know them already. 
	

	
	
		
		

		
		
	


	




 I will need the collaborators because I don't own ES headphones and I probably won't buy them for this project. I also would need to input from a few folks on what you performance you want. DC voltage and AC swing and anything else.

 Can't guarantee that I can get to this right away because there are other projects in the works right now, but I can begin noodling on the design requirements around what I have in mind.


----------



## fishski13

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_What I meant was when you go balanced and have 2 trannys and 3 more boards in there...you may have to run with the top off._

 

i should be able to get the casework finished next week. i will check the temp with my Fluke and report back. i'd be suprised if it's as warm as my Krell amp. 
	

	
	
		
		

		
		
	


	




 chobint,
 they're 4-way cable adhesive mounts from the local mega-hardware store.

 adamus,
 looks great! where did you get those tube "donuts" for the chassis lid?

 PACE


----------



## miky

Finally I finished wiring all the boards.
 That what I have






 1 - 5 (CT-240VAC) -> 280v
 1 - 2 (CT-240VAC) -> 280v
 3 - 4 (6.3VAC-6.3VAC) ->6.7v
 B+ - 250v

 Leads 1&2 -> 6.7v (ECC99)
 Leads 1&3 -> 13.6v (Amperex 8416)

 R-core transformer (R0080-036)

 Can I live with it, or it's too much?


----------



## amphead

Miky, I will leave that one for Runeight. I suspect he will need you to bring those in line.

 Pabbi, I just finished cutting an opening for the switch/iec block and it is now mounted on the back of the chassis, next to the xformer. Power Supply boards are going to be mounted tomorrow. Edit: after the input and output connectors are installed. Momentum is gaining.


----------



## miky

And one more problem. PS gives 250v on 100k test resistor. With both amp boards attached I have only 242-244v. With one board attached (any of two)I have 250v.


----------



## adamus

and thats at max turns of the pot? you have will have to adjust when you plug in the amps. 

 also, is that with the EZ81 or 80. 

 Fishki, the stainless donuts are a tube guards bought from vt4c taken aparts. Looks really good!


----------



## fordgtlover

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Well, I was thinking more Stacker, or whatever it is you are doing with the '*Super Bijou*'... but, seriously, we really need you looking at electrostatics. 

 snip_

 

Is there an update on the Super Bijou?


----------



## miky

Yes, it is at max turns of the pot with the EZ81.


----------



## GeWa

Quote:


 Is there an update on the Super Bijou? 
 

Apart from that, what would be the exact difference between the standard Bijou and the Super Bijou?

 Regards


----------



## runeight

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_Yes, it is at max turns of the pot with the EZ81._

 

miky, what is the voltage at the exposed lead of R7 and R8?


----------



## miky

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_miky, what is the voltage at the exposed lead of R7 and R8?_

 

Power Supply
 R7 - 248v
 R8 - 301v


----------



## runeight

Wow, that is a huge current draw from the PS. What tubes are you using and are you using the stock resistor values in the amps?


----------



## miky

Tubes - EZ81 JJ, ECC99 Gold JJ, Amperex Gold Pin 8416. I am using the stock resistor values + Regal's mods & 470 ohm in R2 (R3-30K, R5, R6, R7 - 10K).


----------



## runeight

OK. Things are now making more sense.

 One more measurement please. What is the voltage at the plates of the input tubes (pin 6).

 The voltage drop across R7 and R8 says that your amps boards are drawing 80mA. This is outside the design capability of the PS, even with EZ81. So we have to reduce the current draw to more like 70mA in order to increase the voltage at R7 (the input to the regulator). I'm not sure exactly how we'll do this, but there is always a way.


----------



## miky

Thank you runeight
 It is 93-94v (pin 6 of 8416 - ground).


----------



## runeight

OK. This says that the first stage is drawing about the right amount of current. Which means that the ECC99s are drawing a huge amount of current. 

 Are you using 1N4002 diodes in the O/P stage?

 Also, could you please disconnect the amp boards from the PS, re-attache the 100k resistor, and measure the voltages at R7 and R8 again.

 Thanks.


----------



## miky

I am using 1N4004 diodes from JRossel's kit.
 The voltages with the 100k resistor:
 R7 - 352v
 R8 - 359v
 I have 283VAC from R0080-036 R-Core transformer (260-230-0-230-260).
 And the fuse was blown twice (1A fast blow).


----------



## runeight

OK. Those are all good voltages and the right diodes.

 So, at the moment I don't know what's happening. You have plenty of HV secondary. What is the HV AC voltage when the amp boards are attached?

 Your input stage is biased about 5mA. I'm not sure about the O/P stage yet.

 Try using a slo blo fuse.

 Try running it for a while. Perhaps a little breakin will help.


----------



## runeight

Miky, when you an opportunity, could you also try another ez81? Your ez81 is dropping quite a lot of voltage. I'm wondering if it's a bit below spec.


----------



## adamus

Bijou is finished






 more pics in the post your builds thread. Really pleased with the way this sounds and looks!


----------



## runeight

Very classy looking. And you even managed to get the rectifier above the top so you can at least see some of its heater.

 I wish I had the casing skills that you guys have.


----------



## amphead

Very nice indeed adamus! Great planning and execution. You made a somewhat challenging build look easy. Very pleasing and elegant look.


----------



## huskydawg9

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Bijou is finished






 more pics in the post your builds thread. Really pleased with the way this sounds and looks!_

 


 What brand of case is that? It looks sharp.


----------



## dBel84

Adam, just wanted to chip in on the compliments - really looks great ..dB


----------



## bhjazz

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Bijou is finished
 more pics in the post your builds thread. Really pleased with the way this sounds and looks!_

 

Excellent. Very professional look!


----------



## adamus

its a hifi2000 case from modushop. If you are european they are really cheap, that only cost £30 all in. 

 Thanks for the compliments chaps - very pleased with it. Now to try some better tubes....


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Dantes, how is your amp doing?_

 

Worst 
	

	
	
		
		

		
		
	


	




 I wait for my EZ81. A friend of mine will give me one, but i did not see him for now.

 I Rewire a little the amp to use it, but now i have a some noise a the left channel and the right one have some creaks that append and disappeared.

 I think i will fully rewire it and shealed all signal wires.


----------



## chobint

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Excellent. Very professional look!_

 

i agree, very professional. I think a silver non-vented hood with some 3d tube guard thingies would really set off the high-end professional look, but of course to each his own. Anyway, those are my CONSTRUCTIVE comments. Again, nice build.


----------



## adamus

I agree, I do need the vents though, even with most of the tubes sticking out there is still plenty of heat, the bijou is hot beast.


----------



## Dantes

adamus, your Bijou is too beautifull... how can i post mine after that...


----------



## AudioCats

Does anybod have the size of the amp boards? this thread is already 100+ long, too many pages to search for such info.... I have a nice wooden box here and I am wondering if the boards will fit in.....

 Thanks


----------



## runeight

The amp board is 3.4" x 2.6". You'll need two of them.

 The PS board is 4.3" x 3.3". Just one of these.

 If you go to the Cavalli Audio website and find the Bijou section, look at the Boards page. You will see links to board drilling templates. These should be to scale and you can print them out to use them as paper boards to test fit into the chassis.


----------



## AudioCats

thanks, so the amp boards will fit. 

 the only problem left is the 6922's, which I don't have any. I do have a bunch of 12AU7, I wonder if they can be make to work.......


----------



## AudioCats

and by the way, where can I buy the amp boards from? I think the group buy was for the full set, I don't really need a power supply board.....


----------



## chobint

AFAIK glassjaraudio.com is the only source for bijou boards. They are sold as full sets there as well.


----------



## amphead

Not sure what you mean by not needing a power supply board. Are you going to build one point to point from scratch? There probably is only the board kit available from Jrossel, which includes the PS board.

  Quote:


  Originally Posted by *AudioCats* /img/forum/go_quote.gif 
_and by the way, where can I buy the amp boards from? I think the group buy was for the full set, I don't really need a power supply board....._


----------



## AudioCats

Thanks guys. Is the glassJar price with shipping included? I got to the payment page and it did not show a shipping charge.

 The reason I didn't want the PS board is, to me, the 260V/260v transformer is the deal breaker. I should already have enough parts in parts boxes to build the amps (well, have to get the 6922 or to make 12AU7 work, but other than that...), however I am not sure I want to built the tube power supply. I can make +250v supply with normal diode circuit and use a thermo delay to provide a soft start, I think I have enough spare parts laying around for that. By going this way, all I need are the boards and possibly the 6922's. 

 At this point the only dynamic phone I have left is my 600 ohm Beyer 990, so I don't want to invest too much into a dynamic amp.....


----------



## Dantes

I had investigate for my noises problemes and i find why for the 2 things.

 For the buzz, it's 2 feedback wires that are too close to the transformer. I will have to separate it from the amp boards.

 For the scratch, it's a crappy tube.
 I'll have to change it. -_-


----------



## runeight

That's great Dantes. Now we just have to fix your power supply.


----------



## miky

I have bad news. The output voltage on PS has gone down up to 102v with 349v on R7 and 358v on R8. 
 With 100k resistor connected to the PS, output voltage yet reads 250v (R7-361v, R8-367v).
 If the mosfets have been blown?


----------



## amphead

Miky, that's another one for Runeight.

 Pabbi, I have mounted the input/output connectors and the L/R volume pots. Next I will mount the PS boards. I had a small fight with the chassis to get the holes for the connectors.


----------



## rhys h

Hi everyone, im getting ready to get a kit from jeff.

 Two questions...

 Does the bijou need warm up time? (I have no experience with tubes)

 Also, has anyone mounted the main tubes off the pcb? using chassis mount sockets? Should this be possible?


----------



## runeight

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_I have bad news. The output voltage on PS has gone down up to 102v with 349v on R7 and 358v on R8. 
 With 100k resistor connected to the PS, output voltage yet reads 250v (R7-361v, R8-367v).
 If the mosfets have been blown?_

 

Miky, I'm sorry to say that these numbers indicate that the fets are blown. You should replace both of them.


----------



## runeight

Quote:


  Originally Posted by *rhys h* /img/forum/go_quote.gif 
_Hi everyone, im getting ready to get a kit from jeff.

 Two questions...

 Does the bijou need warm up time? (I have no experience with tubes)

 Also, has anyone mounted the main tubes off the pcb? using chassis mount sockets? Should this be possible?_

 

rhys_h, tubes need a new minutes of warmup time to get conducting really well. More time is better up to a point then it doesn't matter.

 It is possible to air wire the tubes to the boards. Others have done, but I can't remember who.


----------



## chobint

Quote:


  Originally Posted by *rhys h* /img/forum/go_quote.gif 
_Hi everyone, im getting ready to get a kit from jeff.

 Two questions...

 Does the bijou need warm up time? (I have no experience with tubes)

 Also, has anyone mounted the main tubes off the pcb? using chassis mount sockets? Should this be possible?_

 

If by chance you mean does this amp need a standby switch to allow the tubes to warm up before applying full power, the answer is no. Answer quoted below

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_chobint, the main reason for the tube rectifier is for the slow start on the PS. If everything is working normally you should not need a B+ standby switch. I don't have one and Bijou has been running ok for several years now. 
	

	
	
		
		

		
		
	


	


_


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Miky, that's another one for Runeight.

 Pabbi, I have mounted the input/output connectors and the L/R volume pots. Next I will mount the PS boards. I had a small fight with the chassis to get the holes for the connectors. _

 

Oops - did I mention that was a MilSpec (submarine/ship) case? I do know it is indestructible... and, except for the holes, watertight... 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *rhys h* /img/forum/go_quote.gif 
_Also, has anyone mounted the main tubes off the pcb? using chassis mount sockets? Should this be possible?_

 

Ferrari posted his build a couple of pages back with the tubes air wired.... very impressive. No idea about the risks (if any) to the sound (slower, noise, 
 yada).


----------



## n_maher

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Ferrari posted his build a couple of pages back with the tubes air wired.... very impressive. No idea about the risks (if any) to the sound (slower, noise, 
 yada)._

 

Considering that traditionally most tubes are air wired (think PTP) I'd say there's very little risk in doing it with a PCB based design. I'm sure there's some case where it's a horrible idea (i.e. it lengthens the distance between a pin and a resistor) but I'd imagine most scenarios could be dealt with if one knew what they were doing. Note: as proven repeatedly I don't know what I'm doing.


----------



## luvdunhill

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Ferrari posted his build a couple of pages back with the tubes air wired.... very impressive. No idea about the risks (if any) to the sound (slower, noise, 
 yada)._

 

what about a tube extension cord? 
	

	
	
		
		

		
		
	


	




 Take a tube base that plugs into the PCB sockets and runs up the another tube socket that is mounted on the top... as long as there is a way to plug in the base, this should work like a charm and be totally reversible, in the event that you wish to plug the tubes directly into the PCB.


----------



## m_Lowry

Quote:


  Originally Posted by *rhys h* /img/forum/go_quote.gif 
_Hi everyone, im getting ready to get a kit from jeff.

 Two questions...

 Does the bijou need warm up time? (I have no experience with tubes)

 Also, has anyone mounted the main tubes off the pcb? using chassis mount sockets? Should this be possible?_

 

rhys h, see the "point to point" information on the Bijou web site.
The Bijou Headphone Amplifier


----------



## rhys h

Thanks for all the comments, i will consider both options, thanks luvdunhill for the socket extension idea! I may give that a try.


----------



## adamus

gents,

 I am not happy with my the heat the recessed ez81 is putting out. 

 anyone see a problem with using one of these to raise it up?

Vacuum Tube Socket Saver for 9 pin Sockets (4 pcs) - eBay (item 230296659625 end time Oct-06-08 09:35:50 PDT)


----------



## rhys h

Adam, if you do decide to purchase those, let me know. I would be intrested in 4 and we can split postage, if you are willing that is.


----------



## pabbi1

Quote:


  Originally Posted by *n_maher* /img/forum/go_quote.gif 
_Considering that traditionally most tubes are air wired (think PTP) I'd say there's very little risk in doing it with a PCB based design. I'm sure there's some case where it's a horrible idea (i.e. it lengthens the distance between a pin and a resistor) but I'd imagine most scenarios could be dealt with if one knew what they were doing._

 

Yeah, i just didn't want to _sound_ like a voice of authority, and NEVER think p2p (unless there is no other way).

  Quote:


  Originally Posted by *n_maher* /img/forum/go_quote.gif 
_Note: as proven repeatedly I don't know what I'm doing. 
	

	
	
		
		

		
			



_

 

Gonna have to call bs on this one... that is my job, and several folks working on my stuff in this thread can back me up...


----------



## adamus

pabbi, you are the brave sacrificial pioneer. Without you the balanced bijou would simply be a possibility


----------



## n_maher

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_gents,
 anyone see a problem with using one of these to raise it up?_

 

Again, I'd say probably not. There are some circuits in which there can be a critical path distance issue but it should be one of those things that one of the designers (or someone smarter than me) can answer for you pretty quickly.


----------



## adamus

and i am only talking about the rectifier, the signal carrying tubes are all on raised pcbs.


----------



## pabbi1

Pfft - the pioneers get the arrows, and the settlers get the land... 
	

	
	
		
		

		
		
	


	




 And forget my ramplings about air wired Bijou - Ferrari's is a SOHAII - getting the build threads confused...


----------



## n_maher

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_and i am only talking about the rectifier, the signal carrying tubes are all on raised pcbs._

 

Hard to imagine there would be an issue with air-wiring (or in this case, using a standoff) a rectifier tube.


----------



## luvdunhill

Quote:


  Originally Posted by *n_maher* /img/forum/go_quote.gif 
_Hard to imagine there would be an issue with air-wiring (or in this case, using a standoff) a rectifier tube._

 

RF can be a problem with rectifiers in general.... adamus, give it a go and let people know...


----------



## adamus

think i will, Rhys h, postage is $10 for up to 10 units. price is $10 for 4 units. You want in?


----------



## Ferrari

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_...
 And forget my ramplings about air wired Bijou - Ferrari's is a SOHAII - getting the build threads confused..._

 

There is nothing wrong with what you said about my air-wired Bijou (it is indeed air-wired). 
	

	
	
		
		

		
		
	


	



 Just like my proto SOHA II, this amp is also a build with a personal touch, which includes some modifications.
 It was up and running from the beginning of the prototyping phase, about 9 months ago. The casework was never completed due to my busy work schedule and partly also due to the too many projects I’m working on (Super Leach, β24, balanced β22 for a friend, SOHA II prototyping and some other personal designs).

 I hope to complete the casework for my Bijou in the coming weekend.


----------



## TimmyMac

Quote:


  Originally Posted by *rhys h* /img/forum/go_quote.gif 
_Also, has anyone mounted the main tubes off the pcb? using chassis mount sockets? Should this be possible?_

 

Yes, it's possible. My bijou sounds great. Pics below - I posted them earlier in this thread. Also note that it's a pain in the ass to mount the sockets on the top plate with the pcbs screwed to the bottom plate. I should have made the connecting wires longer. One thing I did to avoid having the heater wires in the bundle running up to the tubes is wire all the heaters off the heater pins of the rectifier tube socket.


----------



## fishski13

amp cased up with a temporary acrylic proto-faceplate - i just need to wire up the pot and jacks.

 took some quiescent temp readings with the Fluke at the FET heatsinks, (running an EZ81), and ambient air near the amp boards. tip of probe inserted deep into the mounting channel of the heatsink, parallel to the FET.

 lid on: 72 C
 lid off: 66 C
 ambient air near amp boards, lid on: 36 C

 max Tj of FET is 150 C: http://www.fairchildsemi.com/ds/FQ/FQP4N50.pdf. i'm not sure what to infer with these numbers, but i understand that an ideal Tj should be less than %50 of the rated maximum Tj. are these temps kosher? i will be ordering boards and bits next week for balanced configuration and am wondering if i need more heatsinking with the extra PS and amp boards stuffed into the same chassis.

 thanks.


----------



## rhys h

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_think i will, Rhys h, postage is $10 for up to 10 units. price is $10 for 4 units. You want in?_

 

Yeah that will be fine, if you pm me your paypal address and the total amount you want in $us to make it easier, i will get that sorted out.


----------



## miky

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Miky, I'm sorry to say that these numbers indicate that the fets are blown. You should replace both of them._

 

Will IRF840 be ok?


----------



## runeight

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_Will IRF840 be ok?_

 

Yes, I'm pretty sure that it will. You may see slightly different adjustment of the B+ because they are not exactly the same. But it certainly will regulate.


----------



## miky

Thanks, I will give it a try.


----------



## rhys h

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_And forget my ramplings about air wired Bijou - Ferrari's is a SOHAII - getting the build threads confused..._

 

Bah i searched the whole thread...


----------



## Ferrari

Yikes… the casework of this amp give me some serious headache!


----------



## JamesL

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Yikes… the casework of this amp give me some serious headache! 
	

	
	
		
		

		
		
	


	




http://i72.photobucket.com/albums/i1...eelding566.jpg_

 

suddenly, I feel inadequate...


----------



## Dantes

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Yikes… the casework of this amp give me some serious headache! 
	

	
	
		
		

		
		
	


	




http://i72.photobucket.com/albums/i1...eelding566.jpg_

 

wow ...


----------



## GeWa

I'm not a big fan of putting a tube amplifier into a cardboard box.
 What' that thing with the two knobs by the way?
	

	
	
		
		

		
		
	


	




 Regards


----------



## Ferrari

Quote:


  Originally Posted by *GeWa* /img/forum/go_quote.gif 
_I'm not a big fan of putting a tube amplifier into a cardboard box._

 

Me neither. Hee… how do you know my amps boards are in the cardboard box?
 Anyway, the amps boards will coming out of the cardboard box soon, very soon... since the tubes really need some fresh air. 
	

	
	
		
		

		
		
	


	




  Quote:


 What' that thing with the two knobs by the way?
	

	
	
		
		

		
		
	


	



 Regards 
 

No idea, …you???


----------



## adamus

I would quite like to lick that.

 ferrari, isnt it also you that has a stock of super expensive russian tubes to go in there?


----------



## amphead

Very impressive amp Ferrari!

 Pabbi, I have just finished mounting the PS boards. It's on a roll once again.  Edit: I will be leaving on Saturday morning for the finalization of the Beta22 group build, arriving back home on Sunday evening.


----------



## Dantes

i have a question... are there any problem to apply 7.1V at the heater in place of 6.3V ?


----------



## fishski13

re: power switch contact rating.

 how many amperes does each DAX 370 draw - is it equal to the Filament #1 at 3.5 A? i will have 2 transfos and need an appropriate power switch.

 thanks!


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_i have a question... are there any problem to apply 7.1V at the heater in place of 6.3V ?_

 

Dantes, this will shorten tube life and cause the tubes to draw much more current than what the PS is expecting.

 For 6922 the range of heater voltages (on the spec sheets) is 6.0V to 6.6V. This will be similar for the other tubes.

 Is there a way you can make it lower? Decreasing the heater voltage will also help with the B+ because it will reduce the current drain by the amp boards.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_re: power switch contact rating.

 how many amperes does each DAX 370 draw - is it equal to the Filament #1 at 3.5 A? i will have 2 transfos and need an appropriate power switch.

 thanks!_

 

The current drawn is determined by the power relationship on both sides of the transformer. For example:

 On the secondary side the heaters draw 3A and the 260V draws 70mA. This is a total power of about 37W. Lets say 40W for some headroom.

 The primary must, therefore, deliver 40W. If you're using the 120V primary, then the current is 40W / 120V = 330mA of RMS current draw.

 Any power switch rated at 5A will do to account for the current pulses from the rectifier. You can probably even do 2.5A if you have to.

 Edit: This is for one transformer.


----------



## fishski13

thanks.


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Dantes, this will shorten tube life and cause the tubes to draw much more current than what the PS is expecting.

 For 6922 the range of heater voltages (on the spec sheets) is 6.0V to 6.6V. This will be similar for the other tubes.

 Is there a way you can make it lower? Decreasing the heater voltage will also help with the B+ because it will reduce the current drain by the amp boards._

 

I will try to wire the transfo with a different configuration but this will lower the primary to 240V.

 In other hand, this transfo make some audible noise. I think i will change it. But it's not easy to find an equivalent to the hammond 370 in france.


----------



## runeight

What transformer are you using? I have forgotten.


----------



## Dantes

huhu, i do not tell you the model because i do not know myself 
	

	
	
		
		

		
		
	


	



 The only thing writen on it it's "Vedovelli" and all voltage informations.

 It's an old one from an old dead equipement, but it is OK.
 It have a lot of wirering possibility.


----------



## Ferrari

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I would quite like to lick that.

 ferrari, isnt it also you that has a stock of super expensive russian tubes to go in there?_

 

If you are talking about this, ...yes!
 However, with 6N1Ps (at much lower cost) in the front end this amp sounds great too.


----------



## Dantes

Here is mine.

 The case is not finished and it will not be as beautifull as some seen here, but it works not too bad 
	

	
	
		
		

		
		
	


	




 The box was a power unit of an old Sun server.
 Just the size... not many room to work in fact 
	

	
	
		
		

		
		
	


	




 I'am happy, it's my first diy project 
	

	
	
		
		

		
		
	


	




 Do not pay attention to the mess in the box


----------



## rhys h

nice industrial look there


----------



## pabbi1

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_Here is mine.

 The case is not finished and it will not be as beautifull as some seen here, but it works not too bad 
	

	
	
		
		

		
		
	


	




 The box was a power unit of an old Sun server.
 Just the size... not many room to work in fact 
	

	
	
		
		

		
		
	


	




 I'am happy, it's my first diy project 
	

	
	
		
		

		
		
	


	




 Do not pay attention to the mess in the box 
	

	
	
		
		

		
		
	


	


_

 

Sun is my ATF for salvage cases, as evidenced by my m³ builds in 911 cases.

 Ron, the suspense is killing me - how does the Bijou look in that case?


----------



## huskydawg9

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_If you are talking about this, ...yes!



_

 

When you put those 6H30-DR's in...are you running stock, or with Regal's mod? I read many posts back that those tubes need to be run with more current then the original build provides. Regal's mod (5mA?) may not even be enough to extract the most from them. My Bijou is running stock at 1mA and my 6H30's (JJ's, not the DR's) don't sound as good as the 6N1P's.


----------



## amphead

Quote:


 *pabbi1* writes: Ron, the suspense is killing me - how does the Bijou look in that case? 
 

The Bijou looks quite good in the large case. The parts/boards just seem to go in obvious places in the layout, for an organized and roomy appearance. It might look good with a black epoxy paint finish, if you mask the boards well with newspaper and tape. Then either a wooden or metal front panel. I will take pictures, when the amp boards are mounted. My wife just received a digital camera awarded to her from a health-care company where she works.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_The Bijou looks quite good in the large case. The parts/boards just seem to go in obvious places in the layout, for an organized and roomy appearance. It might look good with a black epoxy paint finish, if you mask the boards well with newspaper and tape. Then either a wooden or metal front panel. I will take pictures, when the amp boards are mounted. My wife just received a digital camera awarded to her from a health-care company where she works._

 

Well, I thought the Bijou would look good in blue, with the wood fromt panel, like the Blue Hawaii... with a metal badge made from your vector logo file...


----------



## amphead

Yeah, blue with wood panel should look awesome. That's why I haven't done any overt cosmetic work, so that you can customize the way you have in mind. Well, tomorrow I have a long drive once again......


----------



## Ferrari

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_When you put those 6H30-DR's in...*are you running stock, or with Regal's mod?* I read many posts back that those tubes need to be run with more current then the original build provides. Regal's mod (5mA?) may not even be enough to extract the most from them. My Bijou is running stock at 1mA and my 6H30's (JJ's, not the DR's) don't sound as good as the 6N1P's._

 

Non of both! 
	

	
	
		
		

		
		
	


	



 As I mentioned it earlier, this amp is build with a personal touch (same as my SOHA II).
 The amp and its PS are modified to make them more capable to run the 6H30-DR (and 6N1P-EB) at the appropriate higher current bias. 

 Without criticizing the design (I understand the design goals/compromises very well), but running 6H30-DR at the stock 1mA is not worth the tube and the money (better is to give the money to homeless folks).


----------



## runeight

Yes I agree Ferrari. The original design had a power budget in mind and was running the 6922 a little light. A high current tube like the 6h30 is running almost starved for current. But, the regal mod (5mA) puts it at a better op point, still a bit below where it might like to run. It will be interesting to hear results.


----------



## huskydawg9

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_As I mentioned it earlier, this amp is build with a personal touch 
 The amp and its PS are modified to make them more capable to run the 6H30-DR (and 6N1P-EB) at the appropriate higher current bias. 
 ._

 

Care to share your mod to run the 6H30's? Alex mentioned that the PS would have to be tweaked to get the current bias up to where it needs to be.


----------



## Ferrari

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_Care to share your mod to run the 6H30's? *Alex mentioned that the PS would have to be tweaked* to get the current bias up to where it needs to be._

 

Alex (runeight) and I are talking about increasing the quiescent current in the input/phase splitter stages of the Bijou in order to get a better operating point for tubes like 6N30-DR and *NOT* over PS tweak.
 There is nothing to tweak with the PS though. It has its own limit and that’s what we have to live with! 

 To run the 6N30-DR in my build, I am using use a heavier transformer (250V/250mA; 6.3V/6A) and 2 PS (one for each channel) and set the quiescent current in the input/phase splitter stages to ~ 7.5-8mA. 
 Obviously, this is far beyond the spec of the Bijou design and unreachable for an amp with a PS based on a Hammond 270DAX or something like that.


----------



## fishski13

finished casing up my work in progress this morning and flogged it all day. just finished listening to...












 partnered with the HD650, the best bass i've ever heard. Amphead was also right, the sound is huge. more to come... i've gotta get back to the tunes.

 btw, i found out that C5 lytic carries some voltage after being powered down for 3 days. while trying to adjust the height of the boards higher (to better ventilate via the vent holes directly underneath), my crescent wrench slipped underneath C5 and out shot a blue spark - i didn't feel anything, other than entirely stupid.
	

	
	
		
		

		
		
	


	




 feel free to lecture me.


----------



## runeight

LOL. I can't tell you how many times . . .


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_LOL. I can't tell you how many times . . ._

 

you mean, how many times this has happened to you?


----------



## runeight

Yes, I'm afraid so. All those years doing experimental physics.


----------



## fishski13

thanks - my fragile ego has been put at ease.
	

	
	
		
		

		
		
	


	




 i've had a couple of hours with the K701 pairing, no NFB. power doesn't seem to be an issue. in fact, dynamically speaking, it easily bests the Cayin HA-1A i owned for the better part of a year, injecting a greater sense of energy and life. this is fast sounding pairing and can really groove. i can't wait to hear the K701 balanced.


----------



## huskydawg9

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Alex (runeight) and I are talking about increasing the quiescent current in the input/phase splitter stages of the Bijou in order to get a better operating point for tubes like 6N30-DR and *NOT* over PS tweak._

 

I'm willing to help test this for you. I have several extra boards I can use if needed (as opposed to modding my existing build).


----------



## miky

Finally I finished my Bijou (ok, casework and some caps rolling ... 
	

	
	
		
		

		
		
	


	




) and it sounds really great!
 Thanks Alex and all prototypers for doing this amp. My DV332 must start looking for another place. 
 I still have problem with PS (EZ81). When I switch on the amp PS provides 275 (trimmer close) VDC, then after a few minutes it goes to ~242/246 VDC. R7 reads 248v and R8 - 300v.
 I don't have the LED installed.
 It is bad EZ81 or something else?


----------



## runeight

You're welcome Miky. You're not the first Bijou builder to retire a DV because of it.

 There is definitely something amiss in the amount of current being drawn by the amp boards. The two voltages say 78mA. This is extremely high.

 What is the heater voltage on the tubes?


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_thanks - my fragile ego has been put at ease.
	

	
	
		
		

		
		
	


	


_

 

No, I wasn't making fun of you. I've just been zapped so many times. It was easy for me to put myself in your shoes. 
	

	
	
		
		

		
		
	


	




 But, the interior of the PS is still dangerous so please be careful.


----------



## fishski13

copy. 

 any power-up/down recommendations? as a general rule, i make sure my phones are not plugged in on power-on, but will often leave them plugged in when powering down. i will do some DC off-set measurements tomorrow when i fine tune the PS - 50 hrs of continuous operation.


----------



## holland

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Yikes… the casework of this amp give me some serious headache! 
	

	
	
		
		

		
		
	


	


_

 

Nice work, Ferrari. I can't quite make it out, but is the casework complete? I can't tell if the headphone jack is just a hole or not.  Either way, the blue diffuse backlight coming out of the headphone jack is quite nice.

 What transformer are you using? I probably missed it. I think it's time I finally build my Bijou in the next few months, and I need to get up to speed on all the tweaks.


----------



## amphead

Holland welcome to the "dark" side of amp building. 

 Pabbi, I will mount the amp boards tomorrow, after the white line fever recedes. You should be seeing pics of the progress soon as well. I know I know the suspense is unbearable, and it feels like watching molasses flow uphill.


----------



## pabbi1

Well, if you feel the need to punch some vent holes prior to dropping in the boards, feel free. And, I was thinking this weekend how much better the Bijou was going to sound than the current rig... well, at least until the BH gets back, running xf2. That will be a shootout.

 Sounds like the end is in sight.


----------



## luvdunhill

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_btw, i found out that C5 lytic carries some voltage after being powered down for 3 days._

 

my favorite way to find this out is when you have a couple wires coming from say an unregulated PSU with a large cap and you measure out the two wires to be the same length and then cut them with some cutters... nice big flash and pop just a few inches away from your hands


----------



## runeight

Yes, done that too. The current was so high the cutters wound up with two notches in the blades where the wires were cut and very tiny blobs of melted metal flew out and stuck into the plastic of my glasses.


----------



## fishski13

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_my favorite way to find this out is when you have a couple wires coming from say an unregulated PSU with a large cap and you measure out the two wires to be the same length and then cut them with some cutters... nice big flash and pop just a few inches away from your hands 
	

	
	
		
		

		
			



_


----------



## luvdunhill

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yes, done that too. The current was so high the cutters wound up with two notches in the blades where the wires were cut and very tiny blobs of melted metal flew out and stuck into the plastic of my glasses. 
	

	
	
		
		

		
		
	


	


_

 

yeah, or the irresistible urge to find out if a device is running hot and shorting the screw to the tab with your finger, despite the use of an isolator. I did this with ended up with both an entry and exit holes a few millimeters apart on my index finger ...


----------



## chobint

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yes, done that too. The current was so high the cutters wound up with two notches in the blades where the wires were cut and very tiny blobs of melted metal flew out and stuck into the plastic of my glasses. 
	

	
	
		
		

		
		
	


	


_

 

LOL, I accidentally arced a short piece of solder across the mains voltage before I got all the heat shrink on my amp. It splattered everywhere.


----------



## Ferrari

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Nice work, Ferrari. I can't quite make it out, but is the casework complete? I can't tell if the headphone jack is just a hole or not.  Either way, the blue diffuse backlight coming out of the headphone jack is quite nice._

 

Obviously not! It was trying only a part of the faceplate out. Unfortunately I have to travel for work again and will not be back home before saturday, so I will try to finish it in the coming weekend. There will be NO backlight coming out of the headphone jack when completed!

  Quote:


 What transformer are you using? I probably missed it. 
 

This one. PS output rock solid at 250V with EZ81 rectifier.


----------



## holland

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Holland welcome to the "dark" side of amp building. _

 

Thanks. I've had the boards since the initial group buy. Talk about procrastination...but not as bad as my Dynahi which, till this day, sits in half built state. I'll probably start building next month, give me some more time for research and parts sorting/selection and orders. The PCBs look like it'll just take a day to stuff, if that much at all.

 Reading through this thread, I hope I hit none of the snags. I'm definitely not looking to see any self-inflicted flesh wounds. 
	

	
	
		
		

		
		
	


	




 Are tubes safe to be exposed? I intend to internal mount the transformer and all the wiring, caps, etc., leaving just the tubes out. I don't want anything on top of it (cage, etc.), but am concerned about electrocution (can the internals of tubes arc outside the tube?), particularly with kids in the vicinity. I have heard stories of arcing in really high voltage scenarios, but am not sure for something like this.


----------



## runeight

I have never heard of arcing outside the glass at the voltages where we are using the tubes. They have been safely used in lots of audio equipment where the tubes are sticking out the top. I guess this doesn't mean it's never happened, but in in the last 40 years, I've not ever seen a story about this. Now, when you get to really HV things are different. Very different.

 However, as you know, with regards to kids, the glass will be very hot and can create serious burns if they actually grab and hold. So, just be sure that they are protected from that.


----------



## amphead

The short answer is yes, it is safe to have the tubes exposed. The tube envelope is made of glass/silicon. Silicon is an insulator unless doped with another substance, but there are reasons not to touch tubes, because you may be burned, depending on current draw. If you touched running tubes with wet fingers, I wouldn't give you any guarantees for how long you would be around afterwards. So amplifiers with exposed tubes are not children/pet friendly for obvious reasons there. Exposed tubes help the chassis to run cooler, however they are exposed to the possibility of being broken when struck accidently, however that might occur. Edit: LOL, I posted the same time you did Runeight and we both touched on the same ideas.


----------



## holland

Thanks. I will search for some more enclosed tube protectors instead of the more open ring type ones.


----------



## dBel84

You can find these very cool ones at VT4C - pricey I know.







 ..dB

 EDIT

 VT4C also sells the r-core transformer which can be used for the bijou ( $32 )


----------



## JamesL

Would there be anything special I should keep in mind if I were to do a 2-chassis bijou? Would the star-ground still be necessary?


----------



## dBel84

The primary thing that comes to mind would be the umbilical, it would be better to keep the HV and heater separate thus 2 umbilicals and make sure there is some locking mechanism so that they don't pop out easily. Your Grounding can still be focused on a ground node in the psu chassis..dB


----------



## luvdunhill

Quote:


  Originally Posted by *JamesL* /img/forum/go_quote.gif 
_Would there be anything special I should keep in mind if I were to do a 2-chassis bijou? Would the star-ground still be necessary?_

 

I would think twice before going this route. Assuming the single chassis implementation is well designed, there are a few benefits, such as less capacitance needed after regulators which can have a positive effect on the amplifier, as well as better immunity from EMI/RFI. I did some comparison using one of Tangent's LMNP devices and noticed that I actually got less noise from the power supply in the single box configuration. There may well be reasons for using a separate power supply, but I'd like to suggest that it is not always a better choice like many people think.


----------



## JamesL

Thanks for the suggestions.
 luvdunhill, sonic benefits aren't the primary reason I'm thinking of using a dual chassis, though if there are any significant disadvantages to doing so, I will rethink it.


----------



## fishski13

while measuring DC offset last night, i noticed that there is attenuated buzzing with the pot at 1/2, gets louder when turned up, then fades again at full travel. no noise when pot at sane listening levels, in fact, dead quiet. i have Amphead's ground mod on the PS.

 so i did some troubleshooting...

 -installed ground loop breaker = did nothing
 -rechecked and tightened grounds/starground = nothing

 i then disconnected interconnect from source to amp - buzzing got louder. so i shorted the Phoenix connector Input to Input ground with a short lead, with the pot connections intact. voila, dead silent throughout all positions on my cheap Radio Shack 100K pot.

 currently, i have my L/R input phonos connected to pot with a single 4 wire Mogami mic cable. 1 individual wire connects to each of the L/R signals and grounds. i've tried disconnecting the shielding from the phono jack, but no love. 

 my pot is mounted on acrylic, with a tagged wire running directly to star ground from the body. maybe some solder could have leaked into the pot from the hole that i tacked the ground wire to. this ground tag spot also happens to correspond to the area of travel on the pot where i get the buzzing.

 any suggestions as to what to do next? crap pot?






[/IMG]






[/IMG]


----------



## chobint

As always not 100% here but, it looks like a grounding loop at your RCA's. They appear to be grounded to both starG and thru the input board. And all the noise from the starquad shield could potentially be going thru your input ground, which can cause some bad noise from my experience. I think (?) its always best if shielding is separately grounded to starG.


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_As always not 100% here but, it looks like a grounding loop at your RCA's. They appear to be grounded to both starG and thru the input board. And all the noise from the starquad shield could potentially be going thru your input ground, which can cause some bad noise from my experience. I think (?) its always best if shielding is separately grounded to starG._

 

i tried this. hum is louder, again starts at 1/2 volume, but now lasts all the way to full clockwise.


----------



## Jrossel

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_As always not 100% here but, it looks like a grounding loop at your RCA's. They appear to be grounded to both starG and thru the input board. And all the noise from the starquad shield could potentially be going thru your input ground, which can cause some bad noise from my experience. I think (?) its always best if shielding is separately grounded to starG._

 

I second this. The green wire from the RCAs to the star ground shouldn't be there. And it should not connect the L and R together.

 JR


----------



## amphead

It may take quite a bit of experimentation Fishski13. It sometimes becomes the challenge you fight for quite awhile. Try to enjoy the process of fixing it, and it will be worth the time spent. I kept trying/experimenting until the noise was gone.

 Pabbi, I have installed 2 of the amp boards, but I have to back-up one step on the attenuators. The key hole isn't securing the right attenuator from rotating. I may have to mount them with the attenuators mounted at 90 degrees/left rotated. There was a pre-existing hole that ended up causing trouble for the attenuators key(the post that holds it at 0 degrees). If mounting at 90 degrees is OK with you, that would solve the problem. Edit: it would only change the look from the inside of the amp and would function just fine.


----------



## fishski13

am i correct ina ssuming that if i've shorted Input to Input Ground with the pot connections intact, my noise issue is from pot and/or pre-pot? 

 my ground loop breaker is 10R 5Watt in parallel with a 0.1 uF cap inserted between IEC ground to star ground. should i try to place the ground loop breaker between both L/R Input star ground connections to actual star ground, or from the PS star ground to actual star ground?

 i will investigate my pot wiring tomorrow. 

 thanks.


----------



## fishski13

update...as i said before, the buzzing got worse after re-wiring correctly. this was with the interconnects from my DAC1 inserted, but the DAC1 was turned off. i just turned it on this morning and the buzz is the quietest i've heard yet, but now the pot has some faint noise, crackling, but only when the pot is rotated.

 i will also try moving the star ground position, and maybe try adding some aluminum mass. it's currently on one of the alodined internal dividers. i also reflowed all ground crimps when doing the rewire last evening.







[/IMG]


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, I have installed 2 of the amp boards, but I have to back-up one step on the attenuators. The key hole isn't securing the right attenuator from rotating. I may have to mount them with the attenuators mounted at 90 degrees/left rotated. There was a pre-existing hole that ended up causing trouble for the attenuators key(the post that holds it at 0 degrees). If mounting at 90 degrees is OK with you, that would solve the problem. Edit: it would only change the look from the inside of the amp and would function just fine._

 

Way fine by me - substance over form, always.


----------



## chobint

as always, disclaimer I'm not a pro at this but, do you mean to say that the noise occurs from pot travel? or from when the volume is turned up? if it's dead silent besides during pot travel then you're looking good amp wise, and a new pot *should* fix it.


----------



## huskydawg9

I've just completed Regal's mod and everything is working ok. The sound is noticeably improved with both the 6N1P's and the 6H30's. I did learn a valuable lesson though... when I was adjusting the trim pot on the PS, I must have leaned a little too close to the heatsink with the screwdriver as I got a huge spark (I'm reasonably sure I didn't actually touch it). Fried the mosfets and smoked R4. Luckily, I had spares. I wrapped my screwdriver with electrical tape to avoid a reoccurance. 

 What a difference with the 6H30's. Much, much improved.


----------



## dBel84

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_ I wrapped my screwdriver with electrical tape to avoid a reoccurance._

 


 May I suggest isolating the heatsink instead ..dB


----------



## huskydawg9

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_May I suggest isolating the heatsink instead ..dB_

 

Actually the heatsink is isolated. I'm not sure where the spark came from as I only heard it.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_am i correct ina ssuming that if i've shorted Input to Input Ground with the pot connections intact, my noise issue is from pot and/or pre-pot? 

 my ground loop breaker is 10R 5Watt in parallel with a 0.1 uF cap inserted between IEC ground to star ground. should i try to place the ground loop breaker between both L/R Input star ground connections to actual star ground, or from the PS star ground to actual star ground?

 i will investigate my pot wiring tomorrow. 

 thanks._

 

Yes, I would say that the first conclusion would be that the noise is pre-pot or in the pot. But this is not always true because shorting the input completely shorts the the pot to ground. If there is noise generated at the pot this can also short out that noise.

 I would suggest trying another pot as cheap and dirty as you can just for the test.


----------



## fishski13

chobint, Alex, and amphead,
 thanks guys. 

 the "hum" and "crackle/scratchy" are 2 different issues, and the act of me touching the volume knob has no effect on their quality or quantity. 

 scratchy when wiper is moving, but this noise disappears when the wiper is stationary. 

 the hum is a "zzzzz" sounding buzz that occurs now at about 3 o'clock and disappears at 4 o'clock. i took out my SPL meter - the buzz "pegs" the needle at 51 dB - so, very quiet.

 the gain of Bijou is a bit high for my tastes when driving the K701 w/o NFB. with the higher Z HD650, gain is fine. i tend to ride the volume a bit, and like to have a bit of travel on the volume knob to get the perfect volume - so i've opted for a single 4 deck balanced TKD pot. having 2 stereo pots to fiddle with may drive me crazy with the K701.

 just ordered another set of boards from Jeff for a balanced Bijou. 
	

	
	
		
		

		
		
	


	




 the Bijou is a phenomenal music maker - the best i've heard.


----------



## fishski13

another couple of questions:
 if driving balanced, the increased voltage gain results in a doubling of gain seen by the headphones? so...if the gain is a bit on the high side for me already now, unbalanced, should i instead go with a 4-deck balanced attenuator (vs. TKD pot), where i can tailor the attenuation curve for the increased gain by running balanced?

 or is there an easier way by reducing gain from the amplifying stages, without sonic detriment?


----------



## amphead

Fishski13, that is probably better answered by Runeight. However, from listening to Pabbi's amp which has the equivalent of a 4-gang attenuator. The HD650's high impedance tames the higher gain very well, and it sounds beautiful.

 Pabbi, time for some pics. I need to mount 2 more amp boards and then wiring begins.........

 Top view.





 Front view:


----------



## adamus

its maaaahoooosive. 

 looks a cracking job so far though amphead.


----------



## luvdunhill

pabbi1:

 noooow you decide to leave lots of room in the case


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_another couple of questions:
 if driving balanced, the increased voltage gain results in a doubling of gain seen by the headphones? so...if the gain is a bit on the high side for me already now, unbalanced, should i instead go with a 4-deck balanced attenuator (vs. TKD pot), where i can tailor the attenuation curve for the increased gain by running balanced?

 or is there an easier way by reducing gain from the amplifying stages, without sonic detriment?_

 

Good question. The only way to reduce the gain is either through NFB or attenutation or different tubes in the front end. Although the last one won't help that terribly much. Edit: I forgot that another way is to remove the cathode bypass cap in the first stage. Some people can hear this audio change, some can't. So you may or may not like it, but the gain will go down.

 So, I would say that a tailored attenuator would be exactly the right thing to do and probably necessary to have any kind of reasonable volume controls.


----------



## pabbi1

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_pabbi1:

 noooow you decide to leave lots of room in the case 
	

	
	
		
		

		
		
	


	


_

 


 Not by choice - the Nabu case was much tighter... you are referring to instead of like this?

 Hard to tell those are the same case, but it will be far roomier once the (new) heat sinks are mounted externally, and the boards directly to them.

 Amphead: Looking good, and also looks like there will be plenty of ventilation in that box... now let's hope the pain was all worth it. Won't be long now... I would like a pic of the wiring on the attenuators to understand my original folly.


----------



## adamus

chaps, on turn off last night i blew a fast blow 1a fuse. 

 powered up witha new one and its fine. What fuse size are you lot using? should i be concerned?


----------



## chobint

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_ Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
hey guys, anyone know what rating of fuse I should be using for the bijou(standard U.S. setup /w jeffs kit and 370dax)? thanks

 

IIRC, I used a 1A slo blo in mine. I think this will do for the newer builds too._

 

Has worked well for me. Blew when I shorted it, otherwise no false blows.


----------



## fordgtlover

1A fast to start with and it blew very quickly. I replaced it with a 1A slo blo - going fine for several months.


----------



## amphead

If it gets annoying go ahead and put 1.5 amp regular fuse in. Thats what I used without problems. You won't burn anything that wasn't going to go anyway.

 Pabbi, I have installed the last 2 amp boards, so your amp will be in the wiring phase tomorrow.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Good question. The only way to reduce the gain is either through NFB or attenutation or different tubes in the front end. Although the last one won't help that terribly much. Edit: I forgot that another way is to remove the cathode bypass cap in the first stage. Some people can hear this audio change, some can't. So you may or may not like it, but the gain will go down.

 So, I would say that a tailored attenuator would be exactly the right thing to do and probably necessary to have any kind of reasonable volume controls._

 

so i've done a bit of research on rotary switches and wiring for an SA, but i want to make sure i get the correct one. for a single balanced rotary switch, either series or shunt, i need: 4 decks, 1 pole per deck, shorting make before break, and 23+ positions? would either of these switches work?

 Electroswitch - C7D0423S
http://www.electro-nc.com/rotaryus/c7.pdf

 Electroswitch - D9G0423S
http://www.electro-nc.com/rotaryus/d9.pdf


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_If it gets annoying go ahead and put 1.5 amp regular fuse in. Thats what I used without problems. You won't burn anything that wasn't going to go anyway.

 Pabbi, I have installed the last 2 amp boards, so your amp will be in the wiring phase tomorrow._


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_so i've done a bit of research on rotary switches and wiring for an SA, but i want to make sure i get the correct one. for a single balanced rotary switch, either series or shunt, i need: 4 decks, 1 pole per deck, shorting make before break, and 23+ positions? would either of these switches work?

 Electroswitch - C7D0423S
http://www.electro-nc.com/rotaryus/c7.pdf

 Electroswitch - D9G0423S
http://www.electro-nc.com/rotaryus/d9.pdf_

 

Yes, I would say that either works. I've actually never built my own attenuator so one thing I can't comment on is the amount of room for the resistors and ease of construction with respect to the two different switch desgins. But otherwise, they will work they way you want them to.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yes, I would say that either works. I've actually never built my own attenuator so one thing I can't comment on is the amount of room for the resistors and ease of construction with respect to the two different switch desgins. But otherwise, they will work they way you want them to._

 

SAs being larger than pots will require a bit more room. i will have to move my boards back a bit, or try mounting the SA back near the input jacks with a shaft/coupler. i've found some 2 decks from Electroswitch that might squeek in on the front if i didn't mind going dual stereo a la pabbi1.


----------



## Ferrari

I have posted some more pics here.


----------



## chobint

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_I have posted some more pics here. 




_


----------



## holland

nice, ferrari. what are the dimensions of your case?


----------



## runeight

Ferrari, you really do have a sense of tecnology as art. Would you consider designing some amps for me?


----------



## AudioCats

That is some truly impressive work Ferrari!


----------



## Dantes

Ferrari, Would you Mary me ? 



 Hum.. no... forgive that


----------



## Dantes

So, ome news of my Bijou.

 I received this morning all tubes i have ordered.

 With the EZ81 i have 250V at the PS output and all voltage seems good. 
	

	
	
		
		

		
		
	


	




 I replaced the 2 6922 phillips with 2 GE 6DJ8. 

 The scratches have disappeared and the sound is improve substantially. 
 Better control, better soundstage and more control basses. They were drooly with the philips.

 The sound is wonderfull ! And the 2 GE are have burned only one hour.



 So, now... some i have to make the finishing of the box and buy some better shealed cables to replace some crapy one.

 But for now, i think i will listen My Bijou for hours 
	

	
	
		
		

		
		
	


	




 Thanks a lot for help and for creating this very good amp


----------



## runeight

That's great Dantes.

 Could you please make a few more measurements for me (don't blow up your mosfets). I would like to know the R7 and R8 voltages along with the AC heater voltage.

 Happy listening. Let us know what you think after a few hours.


----------



## Dantes

No problem, all you would 
	

	
	
		
		

		
		
	


	




 R7 : 257 
 R8 : 304
 AC heater (if i'am not wrong 
	

	
	
		
		

		
		
	


	




) : 298

 I think i'll have some more question, but for now i will go to sleep


----------



## runeight

Dantes, could you please measure the 6.3V heater voltage. After you wake up.


----------



## Ferrari

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Ferrari, you really do have a sense of tecnology as art. Would you consider designing some amps for me? 
	

	
	
		
		

		
		
	


	


_

 

Heehee… you are asking a banker to design amps? 
	

	
	
		
		

		
		
	


	









 (I have left the technical field for too lo…oong as you know).
 To be honest, you are definitely the man when it comes to amps designs.
 Thanks for sharing the good work with the DIY community!


 BTW, thanks to all of you (guys and girl) for the kind words!


----------



## amphead

Banker? You can't tell from the beautiful amps. btw, hope things are OK in Holland/Netherlands due to the crazy financial atmosphere. 

 Pabbi, I have wired the xformer to the iec and almost finished wiring up the PS boards. And, YGPM


----------



## huskydawg9

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Regarding source, there is the Joshua Tree OPUS, which is more FUN (forgiving) than my Azur 840c (384k upsampling DAC), but not as precise. I am _hoping_ the Bijou will team a premium balanced tube amp (not hybrid) with a truly nice balanced source. *The JT guys also have the Buffalo, which is allegedly vastly superior to OPUS, and would be a place to start evaluating,* assuming you aren't wanting to spend > $1500 on a dedicated source._

 

Thanks for the tip.. I have the Buffalo running now with my SE Bijou. Vastly superior to the 24chip DDDAC that I used previously.


----------



## fishski13

a new issue:

 i'm getting intermittant scratchy/static/distortion in one channel only. when i switched around the L and R boards' ECC99 and 6N1P, the distortion followed to the other channel. do i have a bad tube? 

 the pins on the JJ ECC99 look clean/new. however, the pins on the Sovtek 6N1P look pretty oxidized/old. a clue? i may yet try swapping around the 6N1Ps to see if the sound follows before i go to bed. this could then isolate either of the ECC99, or the 6N1P, as the guilty cuprits???

 i have well over 50 hrs on the Bijou, and this noise just appeared out of no where yesterday. 

 thanks!


----------



## adamus

I think yes! the 6n1ps are so cheap it may be wise to try them first - you could also try some dexoit on the pins, although if its only started happening recently this may not work. 

*question*

 My transformer has 2 6.3v secondaries at 3amp rating each (the Rcore). 

 I want to run with 6n1ps,6n6ps and the ez81 = 3.8 amps.

 So i will have to parallel the secondaries. I expect the volatge to be around 7.1v (I have very hot mains). am i right in thinking i will need a dropping resistor of 1ohm ((7.1-6.3)/3.8) at 10 watts to be safe (5w may be ok). 

 I assume it would be too risky to run all the valves of one 6.3v secondary?

 Also, is there a quick way of working out the phase without using a scope? I can get hold of one if necessary. thirdly, will i do any harm leaving the 260v wired up to the PS without the heaters (I am assuming the ez 81 just wont conduct???)


----------



## Dantes

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_a new issue:

 i'm getting intermittant scratchy/static/distortion in one channel only. when i switched around the L and R boards' ECC99 and 6N1P, the distortion followed to the other channel. do i have a bad tube?_

 

Same thing for my bijou. A crappy philips 6922 tube. I replace theses 2 and all works fine.

 Try to exchange one pair of tube to find wich is the crapy one and change this pair.




  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Dantes, could you please measure the 6.3V heater voltage. After you wake up. 
	

	
	
		
		

		
		
	


	


_

 

Ok, as soon as i can. (i am at work now)
 But to do that... i have to use which reference ?
 If i take a measure over the two 6.3V at the transfo, i have nothing.
 if i take with the ground as reference i had 40V with my old tubes.


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I think yes! the 6n1ps are so cheap it may be wise to try them first - you could also try some dexoit on the pins, although if its only started happening recently this may not work. 

*question*

 My transformer has 2 6.3v secondaries at 3amp rating each (the Rcore). 

 I want to run with 6n1ps,6n6ps and the ez81 = 3.8 amps.

 So i will have to parallel the secondaries. I expect the volatge to be around 7.1v (I have very hot mains). am i right in thinking i will need a dropping resistor of 1ohm ((7.1-6.3)/3.8) at 10 watts to be safe (5w may be ok). 

 I assume it would be too risky to run all the valves of one 6.3v secondary?

 Also, is there a quick way of working out the phase without using a scope? I can get hold of one if necessary. thirdly, will i do any harm leaving the 260v wired up to the PS without the heaters (I am assuming the ez 81 just wont conduct???)_

 

Try everything on one secondary and see what happens. Both with respect to voltage and heat from the transformer.

 For phasing, there should be information either pasted on the transformer or a separate which shows the windings. Look for the black dot on both heater windings. To phase properly connect the leads with the black dots together and the the leads without the dots together.

 Resistor calc seems correct, but an awful lot of power to burn.


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_Ok, as soon as i can. (i am at work now)
 But to do that... i have to use which reference ?
 If i take a measure over the two 6.3V at the transfo, i have nothing.
 if i take with the ground as reference i had 40V with my old tubes._

 

Hi Dantes. I am wanting to know the AC voltage across the 6.3V heater winding. I think that you are seeing nothing because you are measuring DC instead of AC. Right?


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_a new issue:

 i'm getting intermittant scratchy/static/distortion in one channel only. when i switched around the L and R boards' ECC99 and 6N1P, the distortion followed to the other channel. do i have a bad tube? 

 the pins on the JJ ECC99 look clean/new. however, the pins on the Sovtek 6N1P look pretty oxidized/old. a clue? i may yet try swapping around the 6N1Ps to see if the sound follows before i go to bed. this could then isolate either of the ECC99, or the 6N1P, as the guilty cuprits???

 i have well over 50 hrs on the Bijou, and this noise just appeared out of no where yesterday. 

 thanks!_

 

fishski13, the kind of noise that you seem to be hearing is almost always contact noise, either a pot, or a tube pin, or something inside the tube itself. Oxidized pins will definitely cause this problem. Since the noise moves with the boards, it's probably not the pot.


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Hi Dantes. I am wanting to know the AC voltage across the 6.3V heater winding. I think that you are seeing nothing because you are measuring DC instead of AC. Right? 
	

	
	
		
		

		
			



_

 


 I think you are rigth... sometime i ask myself if i really had learn electronic basic to school ine this life or in another


----------



## adamus

hum and heat! Its already got a slight hum by running 300ma over spec. 

 Looks like i am going to have to parallel the secs. There are no markings on the transformer, and the wires are the same colour (grey with black CT's), if no-one has a method of correct phasing without a scope i will have to get hold of one. 

 My calcs were a little off, i need to drop about 0.8V @ 3.8amps = 0.22 ohms @ 1watt (5 watt resistor to be safe). shouldnt consume too much power. Wirewound ok for this task?


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Hi Dantes. I am wanting to know the AC voltage across the 6.3V heater winding. I think that you are seeing nothing because you are measuring DC instead of AC. Right? 
	

	
	
		
		

		
		
	


	


_

 

So, i have 6,9V... hum... little too high...

 EDIT: I know why the voltage is too high. My transfo is made for 220V and i have 230V in my house...
 I will have under 6V... hum...


----------



## Ferrari

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Banker? You can't tell from the beautiful amps._

 

Yes, banker 
	

	
	
		
		

		
		
	


	




. Maybe it's just the bad R&D influences in my earlier life. 
	

	
	
		
		

		
		
	


	




  Quote:


 btw, hope things are OK in Holland/Netherlands due to the crazy financial atmosphere. 
 

The financial market is global and... also we -in Europe- can’t escape the storm, unfortunately.
 However we are not badly hit as it happens with some major Americans banks.
 Hopefully the angry storm, which heavily hitting the financial market at this moment will be ending soon.


----------



## Ferrari

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_nice, ferrari. what are the dimensions of your case?_

 

In one or other way I have missed your post, but the dimensions case is W 330mm x D 280mm x H 80mm.


----------



## miky

My update:
 Power supply - 246-249v.
 With line voltage 230vac and 273vac on HV secondaries I have 249v DC, R7 - 253v, R8 - 303v, heaters - 12.6v/6.5v.

 Amp:
 Amperex 8416 - 
 V1A:
 Plate (pin 6) - 96v
 Cathode (pin 8) - 2.4v
 V1B:
 Plate (pin 1) - 197v
 Cathode (pin 3) - 99.4v

 C1 - 49.8v

 ECC 99 - 
 V2A:
 Plate (pin 6) - 127.5v
 Chathode (pin 8) - 2.1v
 V2B:
 Cathode (pin 3) - 130v

 And anothere update:
 Now line voltage it is 235vac and 278vac on HV secondaries - I get 250v DC with R7 - 253.8v and R8 - 305.5v.

 What you say?


----------



## runeight

Well, the numbers say that your two amp boards are drawing 78mA. This is more than the PS has been designed to handle. There seem to be some ECC99s out there that are really conductive. More than we saw during the prototype process.

 If the tubes really want to draw this much current, it's hard to stop them without changing the diode arrangement on the O/P tubes. Your R8 voltage is reasonable, although a little low. I guess you're using the EZ81??

 The front end numbers are good and the voltages on the ECC99 are also good. Even the cathode bias voltage is correct.

 There are enough of these high current draw situations that I've got to take another look at what might be going on here.

 In the meantime there isn't much that you can do. It won't hurt to dial down the B+ to 245V so that the regulator actually regulates.


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I guess you're using the EZ81??_

 

Yes.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_In the meantime there isn't much that you can do. It won't hurt to dial down the B+ to 245V so that the regulator actually regulates. 
	

	
	
		
		

		
		
	


	


_

 

Ok, i will set b+ at 245V.
 If it is all i can do, then i could start to listen to it without problemes 
	

	
	
		
		

		
		
	


	




 Thanks


----------



## runeight

I have been thinking on the high current draw from the tubes. Would one of you guys be willing to run a quick and easy experiment?


----------



## adamus

whats the experiement?


----------



## Dantes

Yes, tell us what you have in mind.


----------



## runeight

I am thinking that the grid leak resistors on the ECC99s (R9 and R11) are too large and that we are getting a bit of thermal runaway.

 So, the test would be to tack solder another 470k resistor in parallel with both R9 and R11 on both boards. And then see if the current draw goes down.

 This will be evidenced by a smaller voltage difference between R8 and R7. So the idea would be to run the amp for about an hour. Measure R8 and R7 and write it down. 

 Turn off and let the voltages bleed down before touching anything!!!

 Then tack the two resistors into place, turn on, run for an hour, and then measure R8 and R7 again. 

 The new resistors will halve the grid leak resistor and, if there is a problem, reduce the small amount of thermal runaway. The voltage drop from R8 to R7 will be smaller.

 Unfortunately, the downside will be that the bass response will suffer a little as the corner frequency of the coupling caps will go up. But, if this solves the current problem we can try to address this other issue later.


----------



## AudioCats

*Interstage coupling capacitors group buy?*

 Hi guys, I have contacted Cal State electronics and they have some 0.18uf/600v VitQ in stock, which will be great for using as interstage caps (4 per amp). physical size is 0.6(D)x 1.8"(L), is anybody interested in a group buy?

 p.s. they are the premium 96P series.


----------



## miky

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I have been thinking on the high current draw from the tubes. Would one of you guys be willing to run a quick and easy experiment?_

 

Ok, I did it. The good news - after 1/2 of hour I have solid B+ 250v. The bad - it is still R7 - R8 256v - 307v.
 Something possibly relevant - upon start-up, for one instant, the one of two 8416 is very intensely glow.
 What's the consequence if I leave this high current?
 Apart that, it sounds really great!


----------



## funch

Man, I can't win for losing. I have one 6N6P tube getting noisy, so I ordered
 4 from the Ukraine on ebay. One month later, no tubes (dispute ongoing 
 through Paypal). So, I decide to switch to ECC99's, and ordered a pair of
 JJ gold pins from AES (about a half hour from my home). Today I get my order, and one of the tube boxes is ..... empty! Somebody just shoot me #%!


----------



## runeight

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_Ok, I did it. The good news - after 1/2 of hour I have solid B+ 250v. The bad - it is still R7 - R8 256v - 307v.
 Something possibly relevant - upon start-up, for one instant, the one of two 8416 is very intensely glow.
 What's the consequence if I leave this high current?
 Apart that, it sounds really great!_

 

Thanks for trying this Miky. The bright flash is common to many European NOS tubes. They are made to do that and this won't hurt anything.

 However, your amp boards are still drawing 75mA and there is no way that the grid resistors, which are now 235k, are too high.

 Looking again at the JJ ECC99 curves, with 125V on the plates and -2.1V on the grids, the plate current should be around 26mA, give or take some. Two of these will be 52mA. 

 Are you using the regal mod? If so, then you're pulling 20mA in the front end which means a total of 72mA. 

 If you're not using the regal mod then the two front ends are taking 4mA, for a total of 60mA.

 Now that I'm looking at this again, I guess with the regal mod 75mA is not out of the question. In which case the PS is having to work pretty hard.

 If your B+ is stable at 250V and it was less than 250V before the mod and if the SQ is still good, then leave the extra resistors in and have a happy time listening.


----------



## randytsuch

Quote:


  Originally Posted by *AudioCats* /img/forum/go_quote.gif 
_*Interstage coupling capacitors group buy?*

 Hi guys, I have contacted Cal State electronics and they have some 0.18uf/600v VitQ in stock, which will be great for using as interstage caps (4 per amp). physical size is 0.6(D)x 1.8"(L), is anybody interested in a group buy?_

 

I am

 Randy


----------



## AudioCats

I will get the pricing figured out tomorrow, likely the caps cost plus $2.5 shipping. 
 If you buy it directly from Cal State they charge a flat rate of $6.50 for conUS shipping.

 By the way, these are the premium 96P series VitQ.


----------



## Dantes

Audiocat, I'am interested too if the cost is not too high.

 runeight: I can't test now, i do not have any componant.
 I will try to find some, but i do not have any electronics shop aside.


----------



## miky

Runeight
 Yes, I’m using the regal mod. What you mean “PS is having to work pretty hard”? Heat or something else? Can I live with it or its need some attention? 
 Can you explain how the grid leak resistor connected to corner frequency of the coupling caps and what value I need for (AKG K701/62 ohm)?
 Don’t know if it help, but I tried to use 6N6P (before R9/R11 mod).
 Result:
 B+ 236.5v
 R7 – 240v
 R8 – 296v


----------



## ericj

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_Man, I can't win for losing. I have one 6N6P tube getting noisy, so I ordered
 4 from the Ukraine on ebay. One month later, no tubes (dispute ongoing 
 through Paypal). So, I decide to switch to ECC99's, and ordered a pair of
 JJ gold pins from AES (about a half hour from my home). Today I get my order, and one of the tube boxes is ..... empty! Somebody just shoot me #%!_

 

Can you describe the internal construction of your surviving 6n6p? I have a few oddballs and so might be able to replace one of yours. 

 Or just sell you a pair.


----------



## runeight

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_Runeight
 Yes, I’m using the regal mod. What you mean “PS is having to work pretty hard”? Heat or something else? Can I live with it or its need some attention? 
 Can you explain how the grid leak resistor connected to corner frequency of the coupling caps and what value I need for (AKG K701/62 ohm)?
 Don’t know if it help, but I tried to use 6N6P (before R9/R11 mod).
 Result:
 B+ 236.5v
 R7 – 240v
 R8 – 296v_

 

You can live with it with no problems. The maximum continuous current for the EZ81 at these plate voltages is listed as 150mA. 75mA is half of that and well within the specs.

 But, the EZ81 is dropping a lot of voltage and handling fairly large current pulses. It's not being damaged by any means, it's just working hard as opposed to being lightly loaded.

 The grid leak resistors are the load resistors for the coupling caps. Along with the value of the cap they form a high pass filter at the grid of each tube. The smaller the resitor or the smaller the capacitor the higher the 3db point is at the low end of the spectrum.

 For the stock values the 3db point is at about 6Hz (into 32R, no NFB). This is a reasonable compromise to using caps that are much much bigger.

 With 235k for the grid leaks the 3db point is about 8Hz. I suspect that you won't notice any change in the bass response because these are so close together and well below 20Hz. Most headphones can't even reproduce 20Hz.

 You can't use the 6N6P for the O/P tubes with the regal mod because they draw way too much current. ECC99s are required to make it possible for the PS to regulate.

 I guess I should remind everyone that the PS was designed with a current budget in mind. It's just not possible to get it to do more than it was designed to do.

 However, if there is ever another run of Bijou Boards I'm going to change the PS to accomodate these larger current draws. It won't be hard to do, but it isn't an easy to retrofit onto the current boards.


----------



## AudioCats

*VitQ group buy*

 ok, a set of (4) 0.18uf/600V 96P Vitamin Q will be $17 shipped con US, $20 for Canada. Will be more for other international destination, I will have to figure it out.

 Cal State has a very limited supply, so I guess we need to limite to one set per person, unless you are doing balanced? (the total available right now is 7 sets.)

 so far, the person who has expressed interest:
 -randytsuch
 -Dante 
 .
 .
 .
 .
 I have started a group buy thread  for it.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_However, if there is ever another run of Bijou Boards I'm going to change the PS to accomodate these larger current draws. It won't be hard to do, but it isn't an easy to retrofit onto the current boards._

 

feel free to elaborate more on the retrofit. i don't understand if this is more of an issue for european mains differences, or for those running an EZ81 - or is it the same difference? 

 i've tried ProGold, 600 sandpaper, and steel wool on the 6N1P pins - no love. called TubeDepot - no questions asked - just send us the tube back. i also bought a second set of tubes to complete balanced operation.

 i should have all my parts needed for balanced operation by mid-next week. i have some D9 series Electroswitch rotary switches on the way for my SAs that i can't wait to get my hands on. i'm going cheap though with a shunt design. i think getting the curve "right" will be quite a task, but defo made easier by the DAC1 (see below). 

 i was worried about the gain in balanced until i realized that my DAC1 has adjustable rear panel-mount trimmers on the analog outputs, as well as XLR/balanced specific attenuation jumpers in the internals. i've cut the SPL dB via the trimmers by 6 dB (with room to spare). i can also attenuate another 10 dB via the internal jumpers. Benchmark has also speced this jumper setting with a reduction in output impedance vs. the original factory settings. the DAC1 is truly a Swiss-Army Knife. i feel like i'm hanging with MacGyver...or something.


----------



## funch

Quote:


  Originally Posted by *ericj* /img/forum/go_quote.gif 
_Can you describe the internal construction of your surviving 6n6p? I have a few oddballs and so might be able to replace one of yours. 

 Or just sell you a pair._

 

 As it stands, I think AES is going to send me another ECC99, but I'll keep 
 your generous offer in mind. Thanks.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_feel free to elaborate more on the retrofit. i don't understand if this is more of an issue for european mains differences, or for those running an EZ81 - or is it the same difference?_

 

The only way to fix the PS for these high currents is to increase the AC secondary voltage (which makes the PS more expensive) or decrease the total resistance supplied by R7 and R8.

 When I initially designed the amp the idea was for it to be ALL tube. I made the one concession on the fet regulator because several builders of other amps thought that the reg really helped the SQ.

 But, if we don't mind a little more sand in the PS we can replace R7, R8, C4 and C5 with cap multipliers. They provide much higher virtual capacitance for the actual value used (good ripple rejection) and they offer much lower resistance in the filter circuit.

 Attached is what I believe would be a suitable sub. The TIP50s must both be heatsunk for 1W. The schematic should make sense.


----------



## Dantes

Many modifications... The actual PS can't easily be modified -_-
 I think it need a new board design.



 I think you have scared everyone 
	

	
	
		
		

		
		
	


	



 *vanish*


----------



## huskydawg9

Quote:


  Originally Posted by *AudioCats* /img/forum/go_quote.gif 
_*VitQ group buy*

 ok, a set of (4) 0.18uf/600V 96P Vitamin Q will be $17 shipped con US, $20 for Canada. Will be more for other international destination, I will have to figure it out.

 Cal State has a very limited supply, so I guess we need to limite to one set per person, unless you are doing balanced? (the total available right now is 7 sets.)
_

 

HOW DO THESE VITAMIN Q'S COMPARE TO RUSSIAN TEFLON FT-3'S???
 I JUST OBTAINED A BUNCH OF THESE. I'M NOT BLOWN AWAY YET, BUT I HEARD THEY TAKE A LONG TIME TO BREAK IN.


----------



## huskydawg9

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_The only way to fix the PS for these high currents is to increase the AC secondary voltage (which makes the PS more expensive) or decrease the total resistance supplied by R7 and R8.

 When I initially designed the amp the idea was for it to be ALL tube. I made the one concession on the fet regulator because several builders of other amps thought that the reg really helped the SQ.

 But, if we don't mind a little more sand in the PS we can replace R7, R8, C4 and C5 with cap multipliers. They provide much higher virtual capacitance for the actual value used (good ripple rejection) and they offer much lower resistance in the filter circuit.

 Attached is what I believe would be a suitable sub. The TIP50s must both be heatsunk for 1W. The schematic should make sense.
_

 

ALEX, WOULD THIS PS BE CAPABLE OF DRIVING 6H30'S AT A HIGHER CURRENT?


----------



## amphead

Wow, a power supply redesign. Interesting.

 Still working on your amp Pabbi, hope to bring it to the Burning Amp show.


----------



## srserl

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Still working on your amp Pabbi, hope to bring it to the Burning Amp show._

 

That might entice me to head over to Burning Amp! I'm looking for a headphone amp project for the new year (that's when I will hopefully finish up everything I have committed
 to building now). Please post here if you are definitely going to take it to Burning Amp.

 Scott


----------



## AudioCats

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_HOW DO THESE VITAMIN Q'S COMPARE TO RUSSIAN TEFLON FT-3'S???
 I JUST OBTAINED A BUNCH OF THESE. I'M NOT BLOWN AWAY YET, BUT I HEARD THEY TAKE A LONG TIME TO BREAK IN._

 

the 96P VitQ's are at about the same performence level as the Auri's, of course, the flavor is very different. 

 The FT-3, on the other hand, easily beats the Auri/VitQ, this is quite obvious if you compare the caps through an electrostatic rig of some kind. VitQ and Auri are both strongly flavored while the FT-3 is much less so, it wins with pure transparency. 

 The problem with FT-3 0.1uf/600V is the large size, 1.1"(D)x 2"(L), and the long wait for them to arrive from Russia, my last purchase took 25 days to get to me. Of course if you already have the FT-3 at hand and has room in the case, then you should definitly use them.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Wow, a power supply redesign. Interesting.

 Still working on your amp Pabbi, hope to bring it to the Burning Amp show._

 

That would be great - especially to listen to other folks opinions about the amp, and how it stacks up.


----------



## chobint

So a mixture of boredom and desire to perform Regal's mod soon here, has yielded the following diagram. Would something like this work for a PSU retrofit? The orange square is a perfboard mounted using standoffs in the existing holes in the PCB, and the pink dots denote rubber feet used to support the other end of the board. That's my best thought on how to mount heatsinks without drilling any holes in the PCB.


----------



## huskydawg9

Quote:


  Originally Posted by *AudioCats* /img/forum/go_quote.gif 
_the 96P VitQ's are at about the same performence level as the Auri's, of course, the flavor is very different. 

 The FT-3, on the other hand, easily beats the Auri/VitQ, this is quite obvious if you compare the caps through an electrostatic rig of some kind. VitQ and Auri are both strongly flavored while the FT-3 is much less so, it wins with pure transparency. 

 The problem with FT-3 0.1uf/600V is the large size, 1.1"(D)x 2"(L), and the long wait for them to arrive from Russia, my last purchase took 25 days to get to me. Of course if you already have the FT-3 at hand and has room in the case, then you should definitly use them._

 

Thanks for your opinion. I am currently running my Bijou with Regal's mod, 6H30's and a 1uF Clarity cap & a 0.22 uF FT-3 in parallel. I bought a ton of the FT-3 0.22's with the idea of using 4 or 5 of these in each channel in a balanced version. I have 2 more sets of boards, and am seriously thinking of pursuing it further. But, I if I do... I want to do it right the first time, with careful consideration of the right components. As I write this, I'm listening to my setup (which I have been modding and tweeking for 6months), and it hasn't sounded any sweeter then it does now. Currently using my SE Bijou with Itunes (Apple lossless) and a USB connected Buffalo as the source (Grado 325i's for the phones). I can't even imagine what a balanced version might sound like... as what I have now is already close to a religious experience. Any comments for improvements?


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_So a mixture of boredom and desire to perform Regal's mod soon here, has yielded the following diagram. Would something like this work for a PSU retrofit? The orange square is a perfboard mounted using standoffs in the existing holes in the PCB, and the pink dots denote rubber feet used to support the other end of the board. That's my best thought on how to mount heatsinks without drilling any holes in the PCB.


_

 

This looks like it will work to me.


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_So a mixture of boredom and desire to perform Regal's mod soon here, has yielded the following diagram. Would something like this work for a PSU retrofit? The orange square is a perfboard mounted using standoffs in the existing holes in the PCB, and the pink dots denote rubber feet used to support the other end of the board. That's my best thought on how to mount heatsinks without drilling any holes in the PCB.


_

 

rune,
 thanks for the mod. i will be placing a final order with Digi-Key on Mon and will include bits for this for my second PS. i will then attempt the mod on the first PS i built. i've never desoldered big lytics like these. i intentionally soldered them a bit high on the PCB for this reason. 

 chobint,
 thanks!! i was going to sit down tonight to figure out the best way to do this mod, and you've beat me to it!!!

 i want to try some P2P with one of the internal dividers as a heatsink.

 nearly finished the amp boards tonight. still waiting for parts to trickle in from a total of 6 different sources.


----------



## adamus

I have been waiting for a scope to connect my two 6.3v secondaries in phase, but thinkign about it, surely this would work:

 all 6.3 wires are grey, with no markings. but with a dmm you can tell which are which secondary. 

 1)disconnect heater secondary from ps board. 

 2) twist two wires together from the different secondary. 

 3) check voltage between free ends. 

 if 12v then dont twist the remaining together. if 0v, then surely we are in phase? 

 or am i being thick (very likely at this time of the morning)


----------



## runeight

adamus, i believe that will work. just make sure you have the primary fused in case it doesn't.


----------



## fishski13

is the resistor 4k7 shorthand for 4.7K?


----------



## runeight

yes


----------



## GeWa

Yep


----------



## randytsuch

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_is the resistor 4k7 shorthand for 4.7K?_

 

yes


----------



## steel

I want to buy some tubes for my Mijou.

 6n6p & 6n6p-i which is right?

 Thanks..


----------



## huskydawg9

Would I benefit with better lower end response by increasing the value of C5 (I'm using 30ohm phones)? Such as 1800uF.


----------



## Ferrari

Quote:


  Originally Posted by *steel* /img/forum/go_quote.gif 
_I want to buy some tubes for my Mijou.

 6n6p & 6n6p-i which is right?

 Thanks.._

 

Both would work fine. 6N6P-i is the the military spec version of the 6N6P.
 However the 6N6P-i requires more heater current than the 6N6P (~900mA instead of ~750mA).
 I have 6N6P-i in mine, work like a charm.


----------



## AudioCats

*Source of low price 4uf/450V Kimber caps -- for output by pass*

 K&K is having some "upgrade pull out" 4uf Kimber caps avaialbe, the ad is here. 

 They will be good for output by-passing. For $5 a pop they are great bargins (normally sells for $16 each new).

 I have not contact K&K to see how many is left. But the original post was from the end of last month so I supposed they should still have some left.


 -- update: they have 4 pieces left.


----------



## runeight

Quote:


  Originally Posted by *steel* /img/forum/go_quote.gif 
_I want to buy some tubes for my Mijou.

 6n6p & 6n6p-i which is right?

 Thanks.._

 

IIRC, 6n6p is the preferred device.


----------



## runeight

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_Would I benefit with better lower end response by increasing the value of C5 (I'm using 30ohm phones)? Such as 1800uF._

 

At some point increasing the size of the O/P cap doesn't really buy you much more. The 1db point with 470u is about 6Hz. That's pretty low. Larger caps will make it lower.

 However, there are three other caps in the circuit that also matter to LF response: C1, C3, C4. Increasing C1 to even just 22u should help a little. Increasing C3 and C4 to 220n will also lower the bass cutoff.


----------



## amphead

Srserl, I will definitely be taking Pabbi's amp, but won't know if it will be finished until it is time to go. It is that tight of a deadline.

  Quote:


  Originally Posted by *srserl* /img/forum/go_quote.gif 
_That might entice me to head over to Burning Amp! I'm looking for a headphone amp project for the new year (that's when I will hopefully finish up everything I have committed
 to building now). Please post here if you are definitely going to take it to Burning Amp.

 Scott_


----------



## steel

Ferrari, runeight, thanks...

 I just want began to built Mijou


----------



## miky

If it’s safe to use C3/C4 (amp) capacitors with 300v voltage rating instead of 400v (I have some vitamin Q 0.68mf/300v)?


----------



## Ferrari

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_If it’s safe to use C3/C4 (amp) capacitors with 300v voltage rating instead of 400v (I have some vitamin Q 0.68mf/300v)?_

 

This amp is feed by 250V DC, so caps rated at 300V should be fine.
 BTW, the actual voltage at C3/C4 is much lower than the PS 250V.


----------



## miky

Thank you Ferrari.


----------



## Ferrari

Quote:


  Originally Posted by *steel* /img/forum/go_quote.gif 
_...

 I just want began to built my Bijou
	

	
	
		
		

		
		
	


	






_

 



 I see a second transformer-alike thing on the pic, is that a choke or a transformer for the 6.3V heater separately?
 Knowing your Dynahi and M³, I’m sure there is a very nice Bijou in the making.


----------



## steel

It's a choke.


----------



## huskydawg9

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_At some point increasing the size of the O/P cap doesn't really buy you much more. The 1db point with 470u is about 6Hz. That's pretty low. Larger caps will make it lower.

 However, there are three other caps in the circuit that also matter to LF response: C1, C3, C4. Increasing C1 to even just 22u should help a little. Increasing C3 and C4 to 220n will also lower the bass cutoff._

 

Increased C1 to 33u. Replaced C3 and C4 with .22uF Clarity caps. It did improve the lower end response (In my case using Grado 325i) , but is probably insignificant for most setups. I imagine this might improve somewhat as the Clarity's break in. 

 I'd like to hear comments about a comparison between the Bijou and the SOHA2. dBEL84 obviously you've heard both...do you have a comparison somewhere I can reference?


----------



## runeight

This sounds about right. Dropping the LF corner freq from 8Hz to 5Hz really shouldn't be audible.

 I actually have a Bijou and SOHA II. I have yet to compare them because I'm not sure that I can do an unbiased comparison and. But, maybe I'll give it a try.


----------



## adamus

comparing my bijou to the soha + jisbos (not soha II)...

 Bijou, beautiful valvey mids, stunnign highs, very organic. Play something rocky and i want it to have a bit more bite. Its a rolls royce, smooth, elegant, and you can drive it all day. 

 Soha+ jisbos
 Strong bass, very good detail. I listen to it for about 45 minutes before i fire up the bijou, which then stays on for the remainer of the night. more like a mustang, strong and fast. justa it....lifeless compared to the bijou.

 IT would be interesting to see measurements, my scientific side thinks the jisbos would have better specs than the bijou. my musical side picks the bijou everytime.


----------



## runeight

Your scientific sense is probably right but . . .

 This depends on the exact configuration of your jisbos. If you are using any of the gain reduction schemes that have been suggested for the buffer, then you are almost certainly supplying a load for the tube that is too small.

 If the jisbos is running stock with a 1M resistor at its input it will still show a rapid decrease in Zi with frequency. You are probably hearing this too.


----------



## miky

My ProtoBijou


----------



## huskydawg9

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_My ProtoBijou 
	

	
	
		
		

		
		
	


	







_

 


 What a beast! I've been trying to figure out how to layout 5 .22uF russian teflon's per channel in my setup...but just don't have the room.


----------



## runeight

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_So a mixture of boredom and desire to perform Regal's mod soon here, has yielded the following diagram. Would something like this work for a PSU retrofit? The orange square is a perfboard mounted using standoffs in the existing holes in the PCB, and the pink dots denote rubber feet used to support the other end of the board. That's my best thought on how to mount heatsinks without drilling any holes in the PCB._

 

gents, how about this board using chobint's idea of a PS add on? The pads on the board sit above the pads on the original PS except that the R7 pad had to be moved slightly so that the auxiliary board would clear C6.

 I've included only two mounting holes so that you can space above the holes that are in the original PS.

 If you guys are interested maybe Jeff R would be willing to make a run of these.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_gents, how about this board using chobint's idea of a PS add on? The pads on the board sit above the pads on the original PS except that the R7 pad had to be moved slightly so that the auxiliary board would clear C6.

 I've included only two mounting holes so that you can space above the holes that are in the original PS.

 If you guys are interested maybe Jeff R would be willing to make a run of these._

 

count me in.

 i just desoldered the C4-5 lytics on my fisrt PS and placed an order to Digikey for the last remaining bits. i have a pretty good idea of how i'm going to P2P this mod. 

 i see a balanced Bijou in the near future.


----------



## fishski13

miky,
 that's some craziness there.


----------



## chobint

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_gents, how about this board using chobint's idea of a PS add on? The pads on the board sit above the pads on the original PS except that the R7 pad had to be moved slightly so that the auxiliary board would clear C6.

 I've included only two mounting holes so that you can space above the holes that are in the original PS.

 If you guys are interested maybe Jeff R would be willing to make a run of these._

 

My god it's beautiful. The holes are even lined up for use of a straight jumper wire. As long as the boards are reasonably priced (5-10 bucks) I'd be in. Otherwise perfboard ho!


----------



## miky

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_If you guys are interested maybe Jeff R would be willing to make a run of these._

 

Count me in too.

  Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_miky,
 that's some craziness there._

 

It's like cooking, a little vitamin Q with russian teflons


----------



## amphead

Miky, be careful with your layout. Otherwise its a trail of tears, hearing the amps beauty, but with some rework necessary to reach the finish line.

 Pabbi, I just could not quite get your amp finished in time for Burning Amp, so I will be working on it Monday. Your headphones shined on the Balanced Beta22. Also I was one of a few winners of the raffle at Burning Amp, and received a 45 lb. project amp that once belonged to the venerated Nelson Pass. He also gave me 4 high power jfets to use in a project. Nelson's a very cool and savvy audio engineer/designer with a very successful audio career. Pics of Pabbi's amp and the project amp tomorrow, I need some sleep. White line fever.


----------



## miky

Quote:


  Originally Posted by *amphead* 
_Miky, be careful with your layout. Otherwise its a trail of tears, hearing the amps beauty, but with some rework necessary to reach the finish line._

 

What you mean exactly? Is something wrong in this layout?


----------



## adamus

gents, anyone tried 8416's and 6n1p's??

 I ahve a selection of both, and both require some work on the amp. 

 Where should my preference lie?


----------



## amphead

Well, you are in the breadboarding stage, so it's too early too tell. To get a quiet background it will usually require a metal bottom with star ground.

  Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_What you mean exactly? Is something wrong in this layout?_


----------



## huskydawg9

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_gents, anyone tried 8416's and 6n1p's??

 I ahve a selection of both, and both require some work on the amp. 

 Where should my preference lie?_

 

I'm not familiar with 8416's but have alternated back and forth between 6n1p's and 6h30's. Alex suggested to me a while back to put sockets on R2 to allow for easy tube rolling, and I'm glad I did. To give you an idea of the improvement, I haven't had 6922's in there since putting the sockets in. If you haven't done it already, Regal's mod makes a difference for the 6n1p's and especially 6h30's .


----------



## adamus

thanks husky, I will probably do regals mod and go for the 6n1ps.


----------



## dBel84

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_gents, anyone tried 8416's and 6n1p's??

 I ahve a selection of both, and both require some work on the amp. 

 Where should my preference lie?_

 

just FYI - mazuki was the only other person I know of to have used the 8416. His was a protobuild and predates any mods..dB


----------



## huskydawg9

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_thanks husky, I will probably do regals mod and go for the 6n1ps._

 

BTW... WITH Regal's mod...

 For the 6n1p R2 will be 180R.

 For the 6H30 R2 will be 1k3.


----------



## willisv

I have been using 8416's for a while now and I really like them but I can't compare them to 6N1P's because I haven't tried them yet. I plan on doing Regal's mod in the near future then I will give them a shot.


----------



## luvdunhill

slightly related to this thread...

 I heard a DIY preamp this past weekend that used a single 6N1P-EV tube. The builder says that he has acquired around 100 of these and has 6 that are of older, slightly different construction. I'm not all that familiar with this tube, but these seemed to have smooth black plates. Sound was starkly different when we compared the 2 tubes. Perhaps something for you guys to be on the lookout for.


----------



## miky

I currently have AKG K701 /62ohm and Rubycon photo flash 410uF caps (C5) bypassed by some Vitamin Q in parallel with K72P-6 (C6). I'm thinking about adding 70uF Obbligato Film Oil caps. What you say about this?


----------



## JamesL

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_I currently have AKG K701 /62ohm and Rubycon photo flash 410uF caps (C5) bypassed by some Vitamin Q in parallel with K72P-6 (C6). I'm thinking about adding 70uF Obbligato Film Oil caps. What you say about this?_

 

I hope you know how big those are..


----------



## willisv

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_I currently have AKG K701 /62ohm and Rubycon photo flash 410uF caps (C5) bypassed by some Vitamin Q in parallel with K72P-6 (C6). I'm thinking about adding 70uF Obbligato Film Oil caps. What you say about this?_

 

The only way to know is to give it a try and see how it sounds. I bypassed C5 in my Bijou with 1uF Mundorf silver/oils and they really improved the sound of my Bijou, although they are a little pricey.

 Has anyone tried the AKG k240 sextetts with their Bijou yet? I just acquired a set and I would strongly recommend them to anyone with a Bijou, they sound so good with this amp!


----------



## chobint

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_I currently have AKG K701 /62ohm and Rubycon photo flash 410uF caps (C5) bypassed by some Vitamin Q in parallel with K72P-6 (C6). I'm thinking about adding 70uF Obbligato Film Oil caps. What you say about this?_

 

I can't comment on obbligato, but I'm using a similar combo. 410uf Rubycon photo, 70uf Dayton poly cap, and 1uf mundorf bypass. I've been happy with the changes.

 to give an idea of size...


----------



## fishski13

wired up the PS mod. no love...no EZ81 glow. nothing went up in smoke though. 

 i have both transformers wired to the IEC inlet, tied in together on the L and N poles, but only one transformer is connected to the single PS i tried the mod on. the second unused transformer is not connected to the second PS board, with business ends taped/encapsulated. i still haven't finished the soldering on the second PS board, but wanted to try powering up one PS board.

 i get continuity between the 2 primaries (black/blue and white/brown) with a resistance of 3.5 ohms. is this normal? 

 i get 0 volts across any of the secondaries. 

 i had no probs the first time around, but i wire in a second transformer, unloaded, and i get zilch. 
	

	
	
		
		

		
		
	


	




 i'm also employing Amphead's PS mods.

 here's an aerial view...btw, i have a new respect for people who do P2P. my first time out was quite the challenge. 






[/IMG]


----------



## adamus

not sue it read that right, but are you saying the tranformer unloaded is not producing any voltage on the secondaries?


----------



## fishski13

sorry about the confusion guys.

 the "operational" transformer was not producing anything when connected to the PS board.

 the second transformer is not hooked up to the PS board - just the primaries to the IEC inlet. but wait...

 i disconnected the second transformer, powered up with only one transformer/PS board - no blown fuse, working fine, and getting 250V on the PS output. i did not have the amp boards connected when blowing fuses, and have not connected them yet. i'm just testing the PS mods. at least my P2P is holding up. 
	

	
	
		
		

		
		
	


	




 disconnecting the second transformer from the IEC is the only change i performed and all is working well.

 when the fuses fried, this was immediately on power up. 

 do i need a higher rated fuse?

 can anyone explain why i was blowing fuses before? 

 both of the transformers are 370 DAZ (DAX). i've triple checked the wiring on the transfos.

 i will get the second PS board mod done this evening, and hope to have both of the PS sorted.

 thanks everyone!

 @ Amphead: awesome!


----------



## pabbi1

Yes, Ron, double awesome - too bad the system restore wiped out the post.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_sorry about the confusion guys.

 the "operational" transformer was not producing anything when connected to the PS board.

 the second transformer is not hooked up to the PS board - just the primaries to the IEC inlet. but wait...

 i disconnected the second transformer, powered up with only one transformer/PS board - no blown fuse, working fine, and getting 250V on the PS output. i did not have the amp boards connected when blowing fuses, and have not connected them yet. i'm just testing the PS mods. at least my P2P is holding up. 
	

	
	
		
		

		
		
	


	




 disconnecting the second transformer from the IEC is the only change i performed and all is working well.

 when the fuses fried, this was immediately on power up. 

 do i need a higher rated fuse?

 can anyone explain why i was blowing fuses before? 

 both of the transformers are 370 DAZ (DAX). i've triple checked the wiring on the transfos.

 i will get the second PS board mod done this evening, and hope to have both of the PS sorted.

 thanks everyone!

 @ Amphead: awesome!_

 

First, let me understand what's happening. You've isolated the new PS with the TIP50 cap multipliers?? And you get 250V from the reg?

 If so, then what happens when you connect this PS to the amp boards and power up? If power up is successful, what is the voltage at the R7 point on the new board. And, we'll need to add one more jumper from the new board to the old board. Later.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_First, let me understand what's happening. You've isolated the new PS with the TIP50 cap multipliers?? And you get 250V from the reg?

 If so, then what happens when you connect this PS to the amp boards and power up? If power up is successful, what is the voltage at the R7 point on the new board. And, we'll need to add one more jumper from the new board to the old board. Later._

 

yes, TIP50 cap multipliers, one PS board, one transformer, 250V on the output with 100K resistor across to ground. both R7 and R8 are connected.

 i need to duplicate this for the second PS board and transfo to power the second set of amp boards. what's with the new jumper - could you elaborate?

 i will hook-up the amp boards later this evening after dinner and measure R7.


----------



## amphead

Pabbi here is your amp again. The white wires connect to the converter outside of the case.


----------



## runeight

Actually, looking at the board again I am wrong about the need for an additional jumper. Connecting the O/P of the cap multiplier board to R7 automatically connects this to R9. It was the R9 connection that I thought had been left out. My mistake.

 Your new R7 voltage should be well above 250V giving the regulator plenty of operating room for the higher current load.

 Your fuse could be blowing simply because with two amps/transformers you have doubled the inrush current into the primaries. I would test each transformer/PS/amps separately first. Make sure that each channel is working. Then rig up both trafos to the power with a larger fuse. This should work.


----------



## pabbi1

Even prettier the second time - so, what is the function of the converter board - your balanced source? inquiring minds wanna know...  ? Pity my transformer cover isn't here yet from vt4c, but will be soon.

 I really cannot wait to see how she sounds now that I have the SOHA II running. Shouldn't be too very long now...


----------



## amphead

Pabbi, the converter is on perfboard and takes an unbalanced signal in, and then adds an additional inverted signal for + and - , 180 degrees out of phase. Therefore allowing me to use my unbalanced source to feed your balanced amp, through your balanced inputs. So starting with just left and right channels coming in to the amp, we get plus and minus left channel and plus and minus right channel. So from 2 signals coming in, we get 4 signals coming in to your amp. Hope that clears it up a bit.


----------



## pabbi1

As I kinda alluded to, but stated all wrong... looks fabulous, as MY wiring would never, ever, not in a million years, look that nice.


----------



## huskydawg9

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_I can't comment on obbligato, but I'm using a similar combo. 410uf Rubycon photo, 70uf Dayton poly cap, and 1uf mundorf bypass. I've been happy with the changes.

 to give an idea of size...


_

 

where do you get the 410uF Rubycon photo's?


----------



## chobint

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_where do you get the 410uF Rubycon photo's?_

 

Well its funny you ask because I asked where amphead got his, and he put up an ebay link...like this 
	

	
	
		
		

		
			



RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 360080999665 end time Nov-17-08 18:13:28 PST)
 same vendor I bought from, shipping is a little slow from china, but excellently packed with a tracking number


----------



## huskydawg9

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Well its funny you ask because I asked where amphead got his, and he put up an ebay link...like this 
	

	
	
		
		

		
		
	


	


RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 360080999665 end time Nov-17-08 18:13:28 PST)
 same vendor I bought from, shipping is a little slow from china, but excellently packed with a tracking number_

 


 Thanks. Are these much better than the electrolytic?
 How does sv compare to volts?


----------



## chobint

Consensus seems to be that they sound good. I think at least 4 or 5 people are using them. Don't quote me on this...but I believe SV is a voltage rating above the normal rating that the cap can handle for repeated short bursts for stuff like flash photography, hence photo caps


----------



## huskydawg9

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Consensus seems to be that they sound good. I think at least 4 or 5 people are using them. Don't quote me on this...but I believe SV is a voltage rating above the normal rating that the cap can handle for repeated short bursts for stuff like flash photography, hence photo caps 
	

	
	
		
		

		
		
	


	


_

 

I've made so many improvements since I first built my original Bijou (and my boards are starting to get beat up to show it)...
 The sound has definitely improved much since I started...but it's hard to say whether or not out of all the things that I have tried, that I have the best possible sound out of the changes I have made or tried. When you get to this point where I am, and it sounds so damn good...improvements are hard to come by. But I will purchase some of these caps and do a comparison. I have switched to the Buffalo for a DAC so am not sure how much of my recent improvements are due to this. The sound right now with the Buffalo, Regals mod, 6H30's, Clarity's for bypass caps sounds so good...
 Although I am tempted to build another version with the photo caps bypassed by a bunch of russian teflons.
 I've had a few beers tonight, so not sure if I am biased...but I believe it's never sounded better. (I've also recently updated C1,C3 and C4..so that might have had an effect).


----------



## miky

Quote:


  Originally Posted by *huskydawg9* 
_I've also recently updated C1,C3 and C4.._

 

What are you currently using for C1?


----------



## huskydawg9

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_What are you currently using for C1?_

 

C1 still using an electrolytic but increased to 33u

 C3 and C4 increased to 0.22u and are using Clarity caps


----------



## huskydawg9

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Well its funny you ask because I asked where amphead got his, and he put up an ebay link...like this 
	

	
	
		
		

		
		
	


	


RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 360080999665 end time Nov-17-08 18:13:28 PST)
 same vendor I bought from, shipping is a little slow from china, but excellently packed with a tracking number_

 

Any thoughts on one of these three?

RUBYCON STROBE PHOTO FLASH CAPACITOR 1500UF 330V H T F - eBay (item 180282201173 end time Oct-25-08 10:54:34 PDT)

PANASONIC 1500UF 400V 85'C ELECTROLYTIC CAPACITOR - eBay (item 360081895117 end time Nov-20-08 15:55:38 PST)

RUBYCON 560UF 450V MXG 105C ELECTROLYTIC CAPACITOR - eBay (item 170086575673 end time Nov-19-08 20:48:28 PST)


----------



## Ferrari

Photo flash or not, these are all electrolytic capacitors with their well-known non-linearities (much worse than the better dielectrics like Teflon, silver mica, MKC…), especially at low voltage levels.

 Electrolytic capacitors _directly_ in the audio signal path are real real *BAD*.


----------



## huskydawg9

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Photo flash or not, these are all electrolytic capacitors with their well-known non-linearities (much worse than the better dielectrics like Teflon, silver mica, MKC…), especially at low voltage levels.

 Electrolytic capacitors directly in the audio signal path are real real *BAD*._

 

I haven't been able to find those caps that you are using in place of the big electrolytic


----------



## fishski13

smoke fumes...

 with the blown fuse problems i was having before, i replaced the 1A with a 2A.

 i wired up the second PS board, in conjunction with the other working PS board, with Amphead's mods, and got a zapping sound, blue light in the EZ81, and the 100R to ground off the one of the heaters smoked. powered down and double checked everything. one of the 0.1u caps in the TIP50 multiplier was not soldered down. fixed this, soldered new 100Rs and immediately fried one of the 100Rs. 

 i used Amphead's heater mod in the other PS without issue. 

 what to do next?

 real big bummer


----------



## amphead

Wow sorry to hear about that! Do you have access to a macro camera setup? We need detailed pics. 

 Edit: as Ferrari has said, electrolytic output caps are for those who can not afford to put in high grade film caps. Good film caps are the best solution.


----------



## digger945

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Photo flash or not, these are all electrolytic capacitors with their well-known non-linearities (much worse than the better dielectrics like Teflon, silver mica, MKC…), especially at low voltage levels.

 Electrolytic capacitors directly in the audio signal path are real real *BAD*._

 


 I use the Black Gate NX(the red ones with X in gold letters) as a coupling cap in the output of my Aikido. 25V/1000uF bypassed with auri 2.2's. Sounds pretty good. Do you know of a 1000uF coupling cap I could try replacing it with?


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_smoke fumes...

 with the blown fuse problems i was having before, i replaced the 1A with a 2A.

 i wired up the second PS board, in conjunction with the other working PS board, with Amphead's mods, and got a zapping sound, blue light in the EZ81, and the 100R to ground off the one of the heaters smoked. powered down and double checked everything. one of the 0.1u caps in the TIP50 multiplier was not soldered down. fixed this, soldered new 100Rs and immediately fried one of the 100Rs. 

 i used Amphead's heater mod in the other PS without issue. 

 what to do next?

 real big bummer
	

	
	
		
		

		
			



_

 

Did you test each PS board separately with only its transformer wired to the inlet and switch?

 When you made amphead's mod did you remove R9, etc?


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Did you test each PS board separately with only its transformer wired to the inlet and switch?

 When you made amphead's mod did you remove R9, etc?_

 

no, since the one of the PS was working, i assumed it wouldn't be an issue to leave it connected at the AC inlet.

 yes, R9 etc. have been left out.


----------



## runeight

Is the other PS still working with a 100k load resistor?

 If so, let's work on the broken board.

 Disconnect the amp boards if they are connected, including their heater wiring.

 Do you have a spare rectifier tube? If so put it in the broken board.

 Disconnect the add-on board where it normally connects to R8.

 Make sure that the two 100R resistors are installed correctly. That is make sure that they are connected to the heater terminals and not any of the HV terminals on the terminal block. Make sure that the resistors are ground where they connect.

 Turn it on and measure the voltage across C6. Assuming that nothing blows up, what is it?

 If this voltage is 340V or higher the rectifier is working. Bleed C6 down before you do anything else.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Is the other PS still working with a 100k load resistor?

 If so, let's work on the broken board.

 Disconnect the amp boards if they are connected, including their heater wiring.

 Do you have a spare rectifier tube? If so put it in the broken board.

 Disconnect the add-on board where it normally connects to R8.

 Make sure that the two 100R resistors are installed correctly. That is make sure that they are connected to the heater terminals and not any of the HV terminals on the terminal block. Make sure that the resistors are ground where they connect.

 Turn it on and measure the voltage across C6. Assuming that nothing blows up, what is it?

 If this voltage is 340V or higher the rectifier is working. Bleed C6 down before you do anything else._

 

thanks! will do tomorrow and get back.

 what do you mean by "ground where they connect"? i have 6" of wire after where the 2 100R connect to reach the star ground point. 

 yes, 100K load across working PS when "fired-up" - but no smoke on this board. i did not have my other DVM connected to this board, only on the broken board. 

 i don't have a spare rectifier tube. is this one toast? if so, i will try powering up only the broken board with the one good rectifier.


----------



## runeight

Just a typo, I meant to say grounded where they connect. What you have is correct.

 If you, perhaps, connected one of the 100R resistors to a heater terminal and the other to the 260VAC terminal the rectifier is probably gone. 

 If this is some other problem, it might have survived. But we have to take this step by step so we don't toast the other good tube.

 While you're in between testing sessions, it might be a good idea to look over the add-on board for the PS that croaked and to make sure that it is all wired correctly. You might also test the continuity between the C and E and B of the TIP50s. If you get anything less than infinite ohms between C and E that device needs to be replaced before using the board. If either the CB or EB diodes are shorted, same deal.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Just a typo, I meant to say grounded where they connect. What you have is correct.

 If you, perhaps, connected one of the 100R resistors to a heater terminal and the other to the 260VAC terminal the rectifier is probably gone. 

 If this is some other problem, it might have survived. But we have to take this step by step so we don't toast the other good tube.

 While you're in between testing sessions, it might be a good idea to look over the add-on board for the PS that croaked and to make sure that it is all wired correctly. You might also test the continuity between the C and E and B of the TIP50s. If you get anything less than infinite ohms between C and E that device needs to be replaced before using the board. If either the CB or EB diodes are shorted, same deal._

 

ok. i will poke around with the DVM. at least i bought some extra TIP50s.


----------



## runeight

Don't forget to discharge the caps on the add-on board too.


----------



## amphead

Runeight, will get you back up.

 Pabbi, I am in the process of shielding your input wiring. Hope to be shipping the amp to you this coming week. The cover to the case is only needed to keep fingers out. The amp is quiet without the cover because of the ground mod, which only works when the amp is wired exactly like my amp, which yours will be soon. Hope the Houston show was enjoyable. Edit: Fishski13 not to worry, I will fix your amp pro bono for labor if you get stuck, but I think Runeight will have you back up.  Shipping from Minnesota can be reasonable with USPS and a little wait time.


----------



## Ferrari

Quote:


  Originally Posted by *digger945* /img/forum/go_quote.gif 
_I use the Black Gate NX(the red ones with X in gold letters) as a coupling cap in the output of my Aikido. 25V/1000uF bypassed with auri 2.2's. Sounds pretty good. Do you know of a 1000uF coupling cap I could try replacing it with?_

 


 With such a large value at relative low voltage operations, you can best stick with the BG-NX 1000µF you are using (or Nichicon Muse ES). Paralleling film caps to get 1000µF will be very expensive (not talking about the size).
 Non-polar BG-NX can be regarded as the best in its sort (there is a kind of BG-religion out there, I know).

 Unfortunately BG-NX is not applicable at high voltage as required in the Bijou (output caps rated at at least 160V).
 I have tried non-polar BG-NH 220µF/160V at the output of my Bijou in the prototyping phase… a big step forward comparing to the stock Panasonic but, … the MKP film caps I’m using now are clearly superior (in terms of transparancy, resolutions and extended but well-defined bass).


----------



## kostalex

I am looking for HD650 amp also serving as preamp for my M-Audio BX8a active monitors. Budget is $500 and I prefer OTL. I narrowed my choices to Woo 3, LD MK IV SE or ... 

 May anybody compare Bijou to any of these two?


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Runeight, will get you back up.

 Pabbi, I am in the process of shielding your input wiring. Hope to be shipping the amp to you this coming week. The cover to the case is only needed to keep fingers out. The amp is quiet without the cover because of the ground mod, which only works when the amp is wired exactly like my amp, which yours will be soon. Hope the Houston show was enjoyable. Edit: Fishski13 not to worry, I will fix your amp pro bono for labor if you get stuck, but I think Runeight will have you back up.  Shipping from Minnesota can be reasonable with USPS and a little wait time._

 

Outstanding - I have some cover work to do, as it is mainly to keep my cats out iof the amp... cannot wait to hear it!

 Your generosity, to all, simply can't be repaid.


----------



## Ferrari

Now my proto Bijou is cased up, I wish that... I have the time to get this thing alive.


----------



## holland

Which caps will you be replacing? Obviously the output (C5, I think), and which else?

 Edit: stupidity. Clearly a balanced amp upon closer inspection.


----------



## Ferrari

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Which caps will you be replacing? Obviously the output (C5, I think), and which else?_

 

On the 4 amp boards: all. 
	

	
	
		
		

		
		
	


	



 But On the 2 PS boards: none, probably long life electrolytic capacitors will be used as usual.


----------



## holland

nvm, silly question.


----------



## huskydawg9

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Now my proto Bijou is cased up, I wish that... I have the time to get this thing alive. 
	

	
	
		
		

		
			








_

 

care to share specific information such as brand and values for each cap in the amp boards??


----------



## Ferrari

C3…C6 are obviously visible in the pic above. 
	

	
	
		
		

		
		
	


	



 For C1 and C2, I still have to take a look in my parts bin to see what I have there. However, C2//R2 can also be a LED.


----------



## digger945

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_With such a large value at relative low voltage operations, you can best stick with the BG-NX 1000µF you are using (or Nichicon Muse ES). Paralleling film caps to get 1000µF will be very expensive (not talking about the size).
 Non-polar BG-NX can be regarded as the best in its sort (there is a kind of BG-religion out there, I know)._

 

Yea, I have substituted all kinds of caps for the BG's, and all with a loss of soundstage and space/detail. And no, I am not a part of the BG _cult_





, these caps came on this amp when I purchased it.
 EDIT: I took a look at the Bijou schematic, it's the same as the Aikido, only I call for a 1000uF bypassed with a 3uF, to your 470uF bypassed with 1uF. Has anyone thought much about transformer coupling? I know I have, just to know the difference.

  Quote:


 Unfortunately BG-NX is not applicable at high voltage as required in the Bijou (output caps rated at at least 160V).
 I have tried non-polar BG-NH 220µF/160V at the output of my Bijou in the prototyping phase… a big step forward comparing to the stock Panasonic but, … the MKP film caps I’m using now are clearly superior (in terms of transparancy, resolutions and extended but well-defined bass). 
 

When you select output caps, do you look for high slew/ripple specs, or just a quality name(apart from high voltage specs)?
 Will you use the same Epcos caps in your new PS? Are these the ones that have a 120Hz ripple rating of like 15-30A? I couldn't tell from your pics if they had the "Sikorel" designation.
 Have you noticed on the Cavelli website the new Super Bijou?
 One more question, what's the idle voltage across the output caps(C5/C6)?


----------



## amphead

Kostalex, if you are serious about building pure OTL, then the Bijou won't work for that. However if you want a really great sounding amp the Bijou will make you happy. It does work very well with HD650's and higher impedance phones.

  Quote:


  Originally Posted by *kostalex* /img/forum/go_quote.gif 
_I am looking for HD650 amp also serving as preamp for my M-Audio BX8a active monitors. Budget is $500 and I prefer OTL. I narrowed my choices to Woo 3, LD MK IV SE or ... 

 May anybody compare Bijou to any of these two?_


----------



## huskydawg9

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_C3…C6 are obviously visible in the pic above. 
	

	
	
		
		

		
		
	


	



 For C1 and C2, I still have to take a look in my parts bin to see what I have there. However, C2//R2 can also be a LED._

 


 The mcaps I assume are for C5. But what value are they? One per is not enough for low impedance phones is it?


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Kostalex, if you are serious about building pure OTL, then the Bijou won't work for that. However if you want a really great sounding amp the Bijou will make you happy. It does work very well with HD650's and higher impedance phones._

 

I am assuming that what amphead means here is that if you want both OTL and OCL then the Bijou won't fit the spec. It is, however, a pure OTL amp, but since it has an output cap it is not an OCL amp.

 Now if you you want OTL and OCL try the SOHA II.


----------



## kostalex

I will gift SOHA II kit to my friend as soon as it will be available. So I will definitely try it also, when he build it 
	

	
	
		
		

		
		
	


	




 Yes, I want OTL (never heard about OTL+OCL tube amps though). Is this wrong thread to ask for any Bijou comparisons to other amps, like Woo 3 or LD MK IV SE ?


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Runeight, will get you back up.

 Pabbi, I am in the process of shielding your input wiring. Hope to be shipping the amp to you this coming week. The cover to the case is only needed to keep fingers out. The amp is quiet without the cover because of the ground mod, which only works when the amp is wired exactly like my amp, which yours will be soon. Hope the Houston show was enjoyable. Edit: Fishski13 not to worry, I will fix your amp pro bono for labor if you get stuck, but I think Runeight will have you back up.  Shipping from Minnesota can be reasonable with USPS and a little wait time._

 

thanks for the offer!

 i will be doing more measurements later tonight. i did do some brief investigating earlier before going to work:

 -i have 0 ohms between one of the heaters and one of the 260V supplies with the rectifier in the socket. infinite resistance with the rectifier removed.

 -from memory, the first TIP50 after the R8 point reads 10-100s Kohms between BC, CE, and BE; and the second TIP50 before the R7 point reads 10s Mohms. i have not removed the TIP50s from the circuit. i've soldered the multipliers P2P - if these numbers look reasonably good, i'd rather not desolder to test, but do wish to do things right.

 i will also post some pics.


----------



## amphead

Quote:


 I am assuming that what amphead means here is that if you want both OTL and OCL then the Bijou won't fit the spec. It is, however, a pure OTL amp, but since it has an output cap it is not an OCL amp. 
 

Sorry about the confusion. I temporarily went back in time to the Futterman OTL without output caps and the direct-coupled approach.


----------



## Ferrari

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_The mcaps I assume are for C5. But what value are they? One per is not enough for low impedance phones is it?_

 

C5 = C6 = 100μF 
	

	
	
		
		

		
		
	


	



 100μF is more than sufficient for my Sennheiser HD-650 with [size=small]l[/size][size=xx-small][size=small]Z[/size]headphone[/size][size=small]l[/size] = 300Ω, but I’m using twice as much.


----------



## miky

Ferrari, what you say about AKG K 701 with Z = 62 ohm?


----------



## Ferrari

Quote:


  Originally Posted by *miky* /img/forum/go_quote.gif 
_Ferrari, what you say about AKG K 701 with Z = 62 ohm?_

 

If I can remember, I have pointed that out a while back. 
	

	
	
		
		

		
		
	


	



 Hopefully you can calculate that for yourself and determine the desired cap size for your AKG K701.


----------



## holland

Any one use an R-core with 6n6p-i and ez81? Did you parallel the 6.3v secondaries or did you run one pair to a pair of boards and the other pair to a single board? Did you need a loading resistor to drop some voltage?

 I can't find the datasheet so I can't tell what the unloaded voltage is.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_thanks for the offer!

 i will be doing more measurements later tonight. i did do some brief investigating earlier before going to work:

 -i have 0 ohms between one of the heaters and one of the 260V supplies with the rectifier in the socket. infinite resistance with the rectifier removed.

 -from memory, the first TIP50 after the R8 point reads 10-100s Kohms between BC, CE, and BE; and the second TIP50 before the R7 point reads 10s Mohms. i have not removed the TIP50s from the circuit. i've soldered the multipliers P2P - if these numbers look reasonably good, i'd rather not desolder to test, but do wish to do things right.

 i will also post some pics._

 

I think your rectifier has an internal short. If you follow the proceedure outlined in a previous post we can eventually solve this problem. In the meantime you might want to order one or two more rectifier tubes.

 So, if you remember, isolate the bad PS board. Remove the R8 connection form the TIP50 board so that the rectifier only sees C6. MAKE SURE THAT YOUR 100R RESISTORS CONNECT TO THE HEATER WIRES AND NOT THE HV. 
	

	
	
		
		

		
		
	


	




 Then fire it up. The voltage at C6 should be 340V to 400V somewhere. Yes? No?

 Also, one of your TIP50s is probably dead too. The first one with the low resistances. Do you have a diode checker setting on your DVM? If so, measure the BE and BC diodes. The BE side should show either infinite or 600mV depending on the polarity of your leads. The BC side should show either 600mV or 4k7.


----------



## adamus

Holland, dont forget you need the bias on the heaters, so i dont think you method of hooking the two sets up will work. 

 I am goign to parallel mine.


----------



## holland

If you use amphead's mod, there is no bias relative to the ez81. I think it is possible, as the heater is then more or less isolated and only related to ground.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I think your rectifier has an internal short. If you follow the proceedure outlined in a previous post we can eventually solve this problem. In the meantime you might want to order one or two more rectifier tubes.

 So, if you remember, isolate the bad PS board. Remove the R8 connection form the TIP50 board so that the rectifier only sees C6. MAKE SURE THAT YOUR 100R RESISTORS CONNECT TO THE HEATER WIRES AND NOT THE HV. 
	

	
	
		
		

		
			





 Then fire it up. The voltage at C6 should be 340V to 400V somewhere. Yes? No?

 Also, one of your TIP50s is probably dead too. The first one with the low resistances. Do you have a diode checker setting on your DVM? If so, measure the BE and BC diodes. The BE side should show either infinite or 600mV depending on the polarity of your leads. The BC side should show either 600mV or 4k7._

 

i'm out of 1/2W 100R - can i use 1/8W temporarily for testing? i can head up to Radio Shack after dinner if not.

 yes, tested with diode checker and one of my TIP50 is shot. i have a couple of extras.

 i'll have a C6 voltage reading sometime after dinner.

 i've also ordered 2 new rectifiers.


----------



## runeight

The 100R will burn about 100mW. More if the heater voltage is higher than 6.3V. So you can get away with 1/8W for about a minute.


----------



## Ferrari

Quote:


  Originally Posted by *digger945* /img/forum/go_quote.gif 
_Yea, I have substituted all kinds of caps for the BG's, and all with a loss of soundstage and space/detail. And no, I am not a part of the BG cult





, these caps came on this amp when I purchased it._

 

As I said earlier, BG-NX can be regarded as the best in its sort.


  Quote:


 EDIT: I took a look at the Bijou schematic, it's the same as the Aikido, only I call for a 1000uF bypassed with a 3uF, to your 470uF bypassed with 1uF. 
 

I have given my thought on it in some post back.


  Quote:


 Has anyone thought much about transformer coupling? I know I have, just to know the difference. 
 

Yes, possible difficulties with the Bijou is the output impedance.


  Quote:


 When you select output caps, do you look for high slew/ripple specs, or just a quality name(apart from high voltage specs)? 
 

When it comes to output capacitors or capacitors applied in speakers passive filters, especially in the mid-range and tweeter sections, there are lots of things to think of.

 But generally, my attention goes to the used dielectric (which largely determine the capacitor behavior and can make or break the sound) and other important parameters such as: dissipation factor (the smaller, the better… determining the pulse response of the cap), as low-inductance as possible and at a lesser degree, the tolerance of the caps.

 Of course, besides the scientific determined parameters, extended listening tests are always an important factor for my choice. At this point, I can borrow some experiences from my other hobby of the latest 20 years: speakers build. The choice of output caps I’m using on my amps currently is coming from there. 


  Quote:


 Will you use the same Epcos caps in your new PS? Are these the ones that have a 120Hz ripple rating of like 15-30A? I couldn't tell from your pics if they had the "Sikorel" designation. 
 

Probably yes, I have 1 box (12 pieces) of these long life Epcos capacitors in my parts bin, 3 pieces are used in my Bijou, and the remaining… well, you know the destination. 
	

	
	
		
		

		
		
	


	



 The caps I have, have no "Sikorel" designation and have a ripple rating of ~ 7A @ 120Hz. The very high ripple rating you are talking about are more likely applicable for the lower voltage caps from the same line.



  Quote:


 Have you noticed on the Cavelli website the new Super Bijou? 
 

Yes, Alex is working on that amp.


  Quote:


 One more question, what's the idle voltage across the output caps(C5/C6)?
	

	
	
		
		

		
		
	


	



 

~125V

 Yikes , you have a bunch of questions. 
	

	
	
		
		

		
		
	


	



 And now, no more questions in the coming 100 years.


----------



## miky

Ferrari, R13(10KΩ).300Ω = R13(50KΩ).60Ω? I mean, if R13=50KΩ can I using 100µF film cap for low impedance headphones with Z = 62Ω?


----------



## Ferrari

...


----------



## Ferrari

Only if you are happy with a corner frequency (–3dB point of the high-pass filter) at far above 20Hz, theoretically?
 But… I don’t think so.


----------



## chobint

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_The –3dB point can be calculated using the following formular: f = 1/(2π.R.C)

 => f = 1/{2π. (R13//Z[size=xx-small]headphone[/size]).C} = 1/{2πC.(10KΩ //Z[size=xx-small]headphone[/size])
 => C = 1/{2πf.(10KΩ //Z[size=xx-small]headphone[/size])} = 1/{2πf.(10KΩ.Z[size=xx-small]headphone[/size])/(10KΩ + Z[size=xx-small]headphone[/size])}_

 

In case anyone else found Ferrari's frequency equation with the // symbol a bit confusing (I'm still not sure what that means 
	

	
	
		
		

		
		
	


	




), here is a simpler derivation:

 f = 1/(2(_pi_)C(10000 * Z[size=xx-small]headphone[/size])/(10000 + Z[size=xx-small]headphone[/size]))

 ...where C is your output capacitance, Zheadphone is the impedance of your headphones and f is the -3dB point
 **Assuming r13 is 10kohm**


----------



## fishski13

runeight,
 i'm getting 383V across C6 with my good rectifier in place. so far so good...

 this is with only one transformer connected and the multiplier disconnected at R8.

 what to do next? 

 thanks!


----------



## runeight

OK. Now replace the bad TIP50(s) on your new board and make sure that the rest of the components are soldered and not damaged. Connect the R8 point and disconnect the R7 point. Measure the voltage on the add-on board where it should connect to R7. What is it?

 Do you have the 100R resistors in place?


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_OK. Now replace the bad TIP50(s) on your new board and make sure that the rest of the components are soldered and not damaged. Connect the R8 point and disconnect the R7 point. Measure the voltage on the add-on board where it should connect to R7. What is it?

 Do you have the 100R resistors in place?_

 

do i measure the add-on at R7 to ground?

 yes, 100Rs are in place.

 i will solder the new TIP50 right now, after i bleed C6.


----------



## runeight

yes, measure at the point where you would connect the add-on to R7 to ground.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_yes, measure at the point where you would connect the add-on to R7 to ground._

 

no luck...i got a crackle/buzz in the rectifier similar to when i fried it last time. voltage was rising on the DVM, but i immediately unplugged from the AC wall.


----------



## runeight

I hate to say the obvious, but there is something wrong.

 What I mean by this is that the rectifier does fine with just C6. Did this also include the amphead heater mod? If so, then we know that that works. If not, maybe there is a problem with it.

 But if it worked with just C6 and the heater mod then connecting the add-on board should not cause this problem, assuming that the add-on board is not shorting the rectifer to ground.

 What happens if you disconnect at R8 again? Does it still crackle? Although the rectifier may be dead again.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I hate to say the obvious, but there is something wrong.

 What I mean by this is that the rectifier does fine with just C6. Did this also include the amphead heater mod? If so, then we know that that works. If not, maybe there is a problem with it.

 But if it worked with just C6 and the heater mod then connecting the add-on board should not cause this problem, assuming that the add-on board is not shorting the rectifer to ground.

 What happens if you disconnect at R8 again? Does it still crackle? Although the rectifier may be dead again._

 






 no shorts on the rectifier. disconnected add-on at R8, turned on, rectifier seems to be working. i didn't take any measurements as i've already de-soldered my test leads off C6.

 so...the problem lies somewhere in the add-on? let me re-flow my P2P and try again.


----------



## runeight

I would say you gotta check that board really carefully for wiring errors, wiring shorts, and bad transistors again. And anything else that might be subtly wrong.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I would say you gotta check that board really carefully for wiring errors, wiring shorts, and bad transistors again. And anything else that might be subtly wrong._

 

resoldered and rebuilt everything...still no love.

 i will order new parts for the multiplier and start from scratch. tear apart will include a CSI-like inspection. i will retrace the testing steps you took me through when i rebuild. i will also order a couple of caps for C4 and C5 in case i need to go back to stock form. it sounded so good stock, i'm starting to regret P2Ping this multiplier mod. i should also order some bread board and instead try it on a board with sockets for the TIP50.

 at least it appears my rectifier survived.

 this is my first project that i've encountered a brick wall; but i think the knowledge i'm gaining will make it worthwhile in the end.

 thanks for your time runeight!!!


----------



## amphead

I suspected something might be happening with the add-on board.

 Pabbi, the input connectors are wired to the attenuators with shielded wiring, and the shield is connected to star ground. I will do a sound check tonight. If all is well, we would be ready to ship. I may be able to carefully pack your headphones/extra cable inside of the amp, for only one box to ship, if you would prefer to do that.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, the input connectors are wired to the attenuators with shielded wiring, and the shield is connected to star ground. I will do a sound check tonight. If all is well, we would be ready to ship. I may be able to carefully pack your headphones/extra cable inside of the amp, for only only one box to ship, if you would prefer to do that._

 

Yes, that would be preferrable - all or none... 

 Pics? You need to tout your work a bit, but more importantly, write up a few listening differences in the bal v unbal versions... 
	

	
	
		
		

		
			





 Oh, and PayPal at the ready to cover those shipping charges - least I can do.

 Can.not.wait.to.hear.it.


----------



## chobint

Sorry to hear about the PS addon :\

 Took out my 410uf electrolytics today to see what pure film sounds like. Doing so revealed a weird problem where a faulty C1 was causing the right channel to only make sound briefly on power up and power down, for a period of time directly proportional to the capacitance of C4...strange. Luckily I had a spare C1 on hand. Anyway, all is well now and I'm very pleased with the change. Currently rockin 71uf total output capacitance with HD650's (~7.5hz -3dB) without significant or even really noticeable bottom end degredation. Mid/top end sounds noticeably better.

 I was thinking about putting a DPDT switch between the large electrolytic and the high voltage side of the output to allow versatility with low impedance phones (410uf and 70uf in parallel). I am concerned though, when the cap is first connected it will result in a momentary short, passing DC while charging. A) I assume DC on the output will harm headphones, so it will probably be an internal switch, not "on the fly" B) Assuming the headphones are removed, will connecting the capacitor harm the circuit if it is in operation, or must the amp be turned off and/or discharged? Any other thoughts are greatly appreciated. Thanks.


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Sorry to hear about the PS addon :\

 Took out my 410uf electrolytics today to see what pure film sounds like. Doing so revealed a wierd problem where a faulty C1 was causing the right channel to only make sound briefly on power up and power down, for a period of time directly proportional to the capacitance of C4...strange. Luckily I had a spare C1 on hand. Anyway, all is good now and I'm pleased with the change. Currently rockin 71uf total output capacitance with HD650's (~7.5hz -3dB) without significant or even really noticeable bottom end degredation. Mid/top end sounds noticeably better.

 I was thinking about putting a DPDT switch between the large electrolytic and the high voltage side of the output to allow versatility with low impedance phones (410uf and 70uf in parallel). I am concerned though, when the cap is first connected it will result in a momentary short, passing DC while charging. A) I assume DC on the output will harm headphones, so it will probably be an internal switch, not "on the fly" B) Assuming the headphones are removed, will connecting the capacitor harm the circuit if it is in operation, or must the amp be turned off and/or discharged? Any other thoughts are greatly appreciated. Thanks._

 

i've wondered about placing a switch as well.

 just ordered parts for the PS add-on including a proto-pad board.


----------



## jamess71

Is there a place where boutique parts are recommended for the Bijou? Similar to the "Can't miss builds" for the Millet Max? I have a kit from Jeff I starting to build and would like to substitute some of the parts now rather than later. 

 What are some of the biggest improvement upgrades you guys have done?

 Thanks
 James


----------



## adamus

I would imagine in order...

 tubes (+regal mod)
 output caps
 bypass caps

 This is assuming you build a silent bijou - if not then completely black background afrom a quality build is top priority.


----------



## jamess71

Thanks adamus I'm reading about the tubes now. I'm assuming your talking about replacing the V1 tube, 6922's with 6N1P's ?


----------



## adamus

yes, and you have many options....

 also the option of ecc99's on v2 position.


----------



## amphead

So many options to consider with the Bijou. It is really quite versatile.

 Pabbi, the listening test says.........delightful! I don't get to hear it with my Tascam CD player which sounds best,(bad wallwart) however using my backup source a walkman mp3 player it is quiet. I can't imagine how good it will sound with your balanced source. I will be eagerly awaiting comments when you get it. I will pack the amp tomorrow(carefully), and we can ship on Friday. Can't wait for you to finally get it. 

 Here's some pics............

 Topview





 Unbalanced/Balanced converter on my leg.....





 Shielded wiring......





 Back of the amp.....


----------



## pabbi1

Just beautiful... can't wait!

 Muchas gracias, mi amigo.


----------



## fishski13




----------



## amphead

This is off-topic but here is the Nelson Pass project amp my raffle ticket won at Burning Amp, with 6 gallons of home-made prickly pear wine behind it.


----------



## jamess71

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_yes, and you have many options....

 also the option of ecc99's on v2 position._

 

Thanks agian adamus, 

 Is the consensus to go with the Regal Mod right off the bat to use better tubes?


----------



## fordgtlover

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_This is off-topic but here is the Nelson Pass project amp my raffle ticket won at Burning Amp, with 6 gallons of home-made prickly pear wine behind it.





_

 

Congratulations on the win. You deserve it.


----------



## adamus

my 6n1p's arrived today, should have the r2 swapped at the weekend. 

 I order 4 tubes, but i received 16 (8 6n1p's and 8 6n6p's......no idea why). anyone have any ideas for the others? could build an aikido preamp? or maybe a valve otuput stage for the dac?


----------



## dBel84

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_my 6n1p's arrived today, should have the r2 swapped at the weekend. 

 I order 4 tubes, but i received 16 (8 6n1p's and 8 6n6p's......no idea why). anyone have any ideas for the others?_

 

you want my address 
	

	
	
		
		

		
		
	


	




 ..dB


----------



## adamus

£8 for 16 tubes, and the 61np's ae the eb version. not bad!

 I contacted the seller, heard nothing back. I expect its not worth the shipping costs to return.


----------



## huskydawg9

Quote:


  Originally Posted by *jamess71* /img/forum/go_quote.gif 
_Thanks agian adamus, 

 Is the consensus to go with the Regal Mod right off the bat to use better tubes?_

 

Do Regal's mod for sure. If you want to roll tubes...then socket R2. Then you can roll from 6922 to 6N1P to 6H30 with ease.


----------



## amphead

Pabbi, the amp has been carefully packed up with the phones, tubes and gender cables. The package goes out USPS priority on Friday. We will be anxiously awaiting the news of it's arrival.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_That was what I read at this link:
Audio Asylum Thread Printer

 Apparently the vendor that I used on ebay has decided to only sell the 410uF at 300v in a 10,000 lot for $5000.00. Go figure.

10kx RUBYCON STROBE PHOTO FLASH CAPACITOR 410UF 300SV - eBay (item 7584355807 end time Jun-11-08 11:53:23 PDT)_

 

Ok, this has been quite a while, but my local surplus guy has these at $1 each - he doesn't do net, but I will offer them up to Bijou builders at cost & postage. I got 10 for starters, and can get 20-30 more in short order.

 I think they are $7-10 each from the eBay vendor.

 Obviously, Ron gets all he wants an NO charge...


----------



## JamesL

Why not. I'll take a pair.


----------



## holland

4. ygpm


----------



## pabbi1

I'll run by tomorrow and pick up all he has, so we'll know what is available in total... I will also post a pic tonight to be sure we are all agreeing it is the correct thing before I go too far...


----------



## adamus

right gents... a question for you. 

 I have the Rcore transformer, so i can use 12.6v tubes, or 6.3v tubes. 

 I have two 8416's and lots of 6n1p's. Both require modifications and work. Which shall i go for?????


----------



## willisv

Why don't you try the 8416's first? The mod is very easy, no cathode resistor change and runs good on stock power suppy. swap a couple of wires, plug them in and listen. If you like them add a resistor to fine tune the voltage, it won't hurt them to run at a higher voltage for a short time.


----------



## adamus

good advice. Shame no one has tried both.


----------



## amphead

Pabbi, your package was sent at 2:00 PM today USPS priority. Should be there Monday, and Tuesday at the latest. Some tubes are wrapped in newspaper and tucked inside the case, while the larger ones are in bubble wrap, also inside the case. There is some Nabu carton styrofoam protecting the L/R volume knobs. They allowed me to use their priority tape, so I put lots of tape on the critical stress points. Let's hope they haven't hired Jim Carrey to deliver. I have my fingers crossed.


----------



## huskydawg9

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I'll run by tomorrow and pick up all he has, so we'll know what is available in total... I will also post a pic tonight to be sure we are all agreeing it is the correct thing before I go too far... 
	

	
	
		
		

		
		
	


	


_

 


 I'll take several or more depending on what everyone else wants.


----------



## huskydawg9

This question is a little off target but...

 I have both a 24chip DDDAC with USB interface and a Buffalo with USB interface. Initially, I thought the buff was better...with the Bijou, but now there is no comparison. I recently added some russian teflons to the DDDAC and I suspect they are getting broke in as the buff isn't even close any more. My question: Is there anything to be gained by adding some teflons to the output of the buffalo?


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, your package was sent at 2:00 PM today USPS priority. Should be there Monday, and Tuesday at the latest. Some tubes are wrapped in newspaper and tucked inside the case, while the larger ones are in bubble wrap, also inside the case. There is some Nabu carton styrofoam protecting the L/R volume knobs. They allowed me to use their priority tape, so I put lots of tape on the critical stress points. Let's hope they haven't hired Jim Carrey to deliver. I have my fingers crossed. _

 













 I would use 'pretty princess', but she isn't available for some reason... oh, and for everyone else, we'll let Ron verify these are the right photo flash caps before I go snatch them all up...


----------



## amphead

Yes, those are identical to what I have used. There is the necessity to solder leads onto the terminals unless someone does the Gewa technique seen quite a few posts back. I have to say that I worry about someone getting nailed with photoflash caps, so be careful. It's not the rapid charge that they are so good at, it's the rapid discharge. Probably would bite pretty good if given the chance over the standard electrolytic. ;-/


----------



## jamess71

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_Do Regal's mod for sure. If you want to roll tubes...then socket R2. Then you can roll from 6922 to 6N1P to 6H30 with ease._

 

Great so the Regal mod it is. 

 pabbi1 I'll take a pair if you've got them. Thanks for the offer

 James


----------



## fishski13

i manged to re-do the add-on for the faulty PS board with P2P on perfboard this time. success...thus far (see attachments). i'm just finishing up twisting the potentiometer to 250V. i think i will also re-do the add-on for the working PS board on perfboard as well, but i have yet to try powering up both PS boards as is first. cross your fingers for me gents! 

 i'm off for the next week and hope to get some serious work done.


----------



## amphead

Nice work man, I hope you are out of the woods! The offer stands if you get into trouble.


----------



## GeWa

Quote:


 There is the necessity to solder leads onto the terminals unless someone does the Gewa technique seen quite a few posts back. 
 

That was post #399

http://www.head-fi.org/forums/4161745-post399.html

 Regards


----------



## pabbi1

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_



_

 

Ok, caps are secured - net cost was $.91 each, and I got 150, which should cover many a Bijou, and is offered only here first as there is a known use, and excellent instruction about how they can be applied. Yes this should be in FS, but, is first and foremost a service for Bijou builders.

 I have a few emails, and would like to simplify this a bit. First, I will guarantee to only cover my cost, as this is pure giveback, so let's do 2 splits: 

 4 caps = $5 (4x.91, + .30 for a bubble envelope, + $1.00 plus on postage)
 10-25 (max) caps = $1 each (Includes box + postage)

 International guys, shalom ya'll, but the paperwork sucks - if several folks in one country want some, I can do that. And, when you PM, please include your mailing addy so I can just package and ship. This will be strictly honor system - early Christmas if your conscience allows.

 My strongest preference is this be paid as an ad hoc donation to Head-fi - the purest form of repayment.


----------



## runeight

That's good news fishski13. When you get everything working please measure the voltages at the R7 point on your new boards. This will tell me how well the idea is working in practice.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_That's good news fishski13. When you get everything working please measure the voltages at the R7 point on your new boards. This will tell me how well the idea is working in practice._

 

good news...*both* PS + add-ons fully operational on perf-padboard.
	

	
	
		
		

		
		
	


	




 the heatsinks i chose are a bit OTT. if my maths are correct, i calculated Tj = 58 C, well below 1/2 specs of 150 C. at least they look cool. 
	

	
	
		
		

		
		
	


	




 i'm using a 2A slow-blow fuse. i may pick up some 1A fuses tomorrow to try again.

 runeright,
 after adjusting for 250V on each board, i'm getting 365-366V at both R7 points - higher than the sans multiplier test point of 279V. looks kosher? V=IR.

 i think i'll retire for the evening with a couple of glasses of vino now that i'm winning the Battle of the Balanced Bijou.

 excuse the golden retriever hair in the photo.


----------



## runeight

These voltages are with no amp boards connected? Or maybe with just a 100k load on the PS? Or with amp boards being powered?


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_These voltages are with no amp boards connected? Or maybe with just a 100k load on the PS? Or with amp boards being powered?_

 


 no amp boards and with a 100K load resistor. i should have the amp boards wired up later on this evening. let me know if you want me to take any other readings.


----------



## runeight

If all is working properly, then just the reading at the R7 point. I just want to be sure that this is now well above 260V. 

 Oh, when current flows your pass mosfet is going to get pretty hot. Hotter than before. And the TIP50s will also warm up because they'll be passing around 70mA. So temps will change in the PS and you may be glad you put those heatsinks onto the BJTs.


----------



## pabbi1

Ok, caps packaged for all who gave me an address - James, Randy, Husky - need mailing info.

 Again, just donate the $$$ directly to Head-fi.

 Still over 100 left...


----------



## fishski13

runeright,
 i'm getting 308-310V at the R7 point after 20 min or so - initially 315V on power-up.

 i only have one set of PS and amp boards wired up. the other PS has a 100K resistor across the output. i received the incorrect Sonicap caps from Sonic Craft for the other set of amp boards. i should hopefully have these by Wed.

 i could be imagining it, but the tubes are glowing a bit brighter.


----------



## runeight

That's good!! Mostly. 
	

	
	
		
		

		
			





 The B+ is set to 250V??

 This would mean that the pass mosfet is dropping about 60V at 70mA which will burn a bit over 4W. How hot is the pass mosfet?

 Also, what is the voltage at the R8 point? 

 Are you using EZ81s?

 Thanks. You are very patient with my questions. 
	

	
	
		
		

		
		
	


	




 If the mosfet is getting too hot we can fix this with a few resistor value changes once I know what the various voltages are.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_That's good!! Mostly. 
	

	
	
		
		

		
		
	


	




 The B+ is set to 250V??

 This would mean that the pass mosfet is dropping about 60V at 70mA which will burn a bit over 4W. How hot is the pass mosfet?

 Also, what is the voltage at the R8 point? 

 Are you using EZ81s?

 Thanks. You are very patient with my questions. 
	

	
	
		
		

		
		
	


	




 If the mosfet is getting too hot we can fix this with a few resistor value changes once I know what the various voltages are._

 

no worries. i've taken a lot from the generous DIY community - if the Dude can give back, the Dude abides.

 i powered down before going out to pick up a 12-pack for a pre-celebration (hopefully) on this election eve.

 so, with 20 min of warm-up i pegged these numbers on the Fluke:

 Q2 = 73 C
 Q1 = 45 C
 TIP50 = 26 C
 R8 = 320V

 B+ set to 250V without amp boards attached - only 100kR.

 yes, EZ81 - and ECC99 + 6N1P on the amp.

 are my DAZ 370s up to the task? i'm picturing Scotty telling Captain Kirk, "I'm giving her all she's got!".


----------



## runeight

Your transformers should be well up to the task.

 But, it's Q2 where the problem could be. So when you fire up with amp boards in place pay attention to the temp of Q2. Don't let the PS run for very long before measuring it.

 I think it's going to get too hot. The two ways to adjust for this are to use EZ80s and to replace the 4k7s with 10k resistors. This will drop the voltage at the R8 point and at the same time burn more power in the BJTs.

 But, first the test . . . after you celebrate.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Your transformers should be well up to the task.

 But, it's Q2 where the problem could be. So when you fire up with amp boards in place pay attention to the temp of Q2. Don't let the PS run for very long before measuring it.

 I think it's going to get too hot. The two ways to adjust for this are to use EZ80s and to replace the 4k7s with 10k resistors. This will drop the voltage at the R8 point and at the same time burn more power in the BJTs.

 But, first the test . . . after you celebrate. 
	

	
	
		
		

		
		
	


	


_

 

what test? 

 Q1 and Q2 are rated for 150 C, are they not? MOSFETs have a negative thermal coefficient? you obviously know more than i do - could you expand?

 the PS boards have been running for a total of 1 hr.

 i'm still pegging around 73 C on Q2 after 45 min.


----------



## amphead

Pabbi, I was hoping they would get it delivered today. Well, OK we'll see what tomorrow brings.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, I was hoping they would get it delivered today. Well, OK we'll see what tomorrow brings._


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_what test? 

 Q1 and Q2 are rated for 150 C, are they not? MOSFETs have a negative thermal coefficient? you obviously know more than i do - could you expand?

 the PS boards have been running for a total of 1 hr.

 i'm still pegging around 73 C on Q2 after 45 min._

 

Yes, but I'm still confused. Is the 73C reading with just a 100k load or with the full amp?


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, I was hoping they would get it delivered today. Well, OK we'll see what tomorrow brings._

 


 Eagle has landed, but I chose to machine out the top last night (safety first - I have too many mobile creatures not to)... and, as always, additional challenges. To be fair, i only spent about 15 minutes with it last night, and will be more diligent this evening.

 I am afraid, in the end, the balanced output of the Cambridge Azur 840c is simply too high for the levels of attenuation... but, more observation is required.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yes, but I'm still confused. Is the 73C reading with just a 100k load or with the full amp?_

 

powering 2 amp boards.


----------



## runeight

OK. Now this makes sense. 

 Yes, the mosfets are 150c devices. Keeping them below 75C is generally good practice, but even 73C means that the junction temp is quite a bit hotter than that.

 So what is the R7/R8 voltage when the amps are powered?

 In the original design, I set the conditions so that R7 and R8 would dissipate a bit more than 1W. This then put the mosfet at about 1.5W

 But the cap mulitpliers don't drop as much voltage as the passive resistors so this means that more voltage is being dropped across the mosfet which leads to higher power dissipation.

 What's happening, based on your previous numbers, is that the mosfet is dropping about 60V at 70mA which is about 4W. This is really more than the heatsinks were designed for in the original design where R7 an R8 took up a lot of this power.

 But, since the BJT cap mulitpliers have very little voltage drop across them we are seeing this across the mosfet.

 I would suggest that it would be better to increase the 4k7s to about 10k. This will put about 1W on each of the BJTs and about 2W on the mosfet. It will be much happier at this power dissipation.

 Of course, I'm using voltage measurements that you sent before and I'm not sure whether they were measured with or without the amps attached.

 Does this make sense?


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_OK. Now this makes sense. 

 Yes, the mosfets are 150c devices. Keeping them below 75C is generally good practice, but even 73C means that the junction temp is quite a bit hotter than that.

 So what is the R7/R8 voltage when the amps are powered?

 In the original design, I set the conditions so that R7 and R8 would dissipate a bit more than 1W. This then put the mosfet at about 1.5W

 But the cap mulitpliers don't drop as much voltage as the passive resistors so this means that more voltage is being dropped across the mosfet which leads to higher power dissipation.

 What's happening, based on your previous numbers, is that the mosfet is dropping about 60V at 70mA which is about 4W. This is really more than the heatsinks were designed for in the original design where R7 an R8 took up a lot of this power.

 But, since the BJT cap mulitpliers have very little voltage drop across them we are seeing this across the mosfet.

 I would suggest that it would be better to increase the 4k7s to about 10k. This will put about 1W on each of the BJTs and about 2W on the mosfet. It will be much happier at this power dissipation.

 Of course, I'm using voltage measurements that you sent before and I'm not sure whether they were measured with or without the amps attached.

 Does this make sense?_

 

yes, perfect sense.

 all measurements were done on the PS with the amp boards connected.

 i should have new readings with 10K replacing 4k7 shortly.


----------



## runeight

OK. Please measure the R7/R8 points when your're finished.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_OK. Please measure the R7/R8 points when your're finished._

 

amp boards connected, with 10 min. or so, here's what i get:

 R8 point = 332V
 R7 point = 308V
 Q2 = 68 C
 Q1 = 40 C
 TIP50 = 30 C

 so if my maths are correct, the Q2 mosfet is dissipating around 1.7 W

 my mosfets are not isolated with pads from heatsinks - only a thin layer of thermal grease.


----------



## funch

Here are some new pix of my 'Blue' Bijou showing all the updates/mod's that
 I've made since it was built.

http://i183.photobucket.com/albums/x...d/100_1521.jpg
http://i183.photobucket.com/albums/x...d/100_1517.jpg
http://i183.photobucket.com/albums/x...d/100_1520.jpg
http://i183.photobucket.com/albums/x...d/100_1516.jpg
http://i183.photobucket.com/albums/x...d/100_1518.jpg
http://i183.photobucket.com/albums/x...d/100_1509.jpg
http://i183.photobucket.com/albums/x...d/100_1510.jpg
http://i183.photobucket.com/albums/x...d/100_1511.jpg
http://i183.photobucket.com/albums/x...d/100_1513.jpg
http://i183.photobucket.com/albums/x...d/100_1514.jpg
http://i183.photobucket.com/albums/x...d/100_1515.jpg
http://i183.photobucket.com/albums/x...d/100_1519.jpg

 Here's what I've done so far:
 Added a separate heater tranny for the PS.
 Regal's mod's.
 Amphead's mod's.
 Choke PS mod, variation 2.
 6H30 gold pin input tubes.
 ECC99 gold pin output tubes.
 EZ81 PS rectifier.
 Auricaps in C3, C4 and C6.
 Changed signal wiring to cryo'ed Vampire (buried under all that shielding).
 Stepped attenuator (50K) from ebay (Taiwan).

 I just installed the stepper yesterday, and now understand the enthusiasm for them. The sum total of all the mod's has produced one fantastic listening experience. It's very detailed and dynamic, yet not at all fatiguing. 

 Thanks, Alex, for all your hard work on this design, and your continued efforts
 in this thread. Thanks, also, to all of you who continue to tweak this great
 design. I finally think I'm done (yah, right!). Now I gotta stop reading this
 forum so I can just enjoy the music.


----------



## fishski13

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_Here are some new pix of my 'Blue' Bijou showing all the updates/mod's that
 I've made since it was built.

http://i183.photobucket.com/albums/x...d/100_1521.jpg
http://i183.photobucket.com/albums/x...d/100_1517.jpg
http://i183.photobucket.com/albums/x...d/100_1520.jpg
http://i183.photobucket.com/albums/x...d/100_1516.jpg
http://i183.photobucket.com/albums/x...d/100_1518.jpg
http://i183.photobucket.com/albums/x...d/100_1509.jpg
http://i183.photobucket.com/albums/x...d/100_1510.jpg
http://i183.photobucket.com/albums/x...d/100_1511.jpg
http://i183.photobucket.com/albums/x...d/100_1513.jpg
http://i183.photobucket.com/albums/x...d/100_1514.jpg
http://i183.photobucket.com/albums/x...d/100_1515.jpg
http://i183.photobucket.com/albums/x...d/100_1519.jpg

 Here's what I've done so far:
 Added a separate heater tranny for the PS.
 Regal's mod's.
 Amphead's mod's.
 Choke PS mod, variation 2.
 6H30 gold pin input tubes.
 ECC99 gold pin output tubes.
 EZ81 PS rectifier.
 Auricaps in C3, C4 and C6.
 Changed signal wiring to cryo'ed Vampire (buried under all that shielding).
 Stepped attenuator (50K) from ebay (Taiwan).

 I just installed the stepper yesterday, and now understand the enthusiasm for them. The sum total of all the mod's has produced one fantastic listening experience. It's very detailed and dynamic, yet not at all fatiguing. 

 Thanks, Alex, for all your hard work on this design, and your continued efforts
 in this thread. Thanks, also, to all of you who continue to tweak this great
 design. I finally think I'm done (yah, right!). Now I gotta stop reading this
 forum so I can just enjoy the music.
	

	
	
		
		

		
		
	


	


_

 

beautiful work!!!

 i'm going with a blue/sapphire theme as well - i have some super bright blue LEDs to illuminate the interior of the amp.


----------



## funch

Thanks. I can't wait to see everyone's amps when they're done. 
 Ferrari's is spectacular.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_amp boards connected, with 10 min. or so, here's what i get:

 R8 point = 332V
 R7 point = 308V
 Q2 = 68 C
 Q1 = 40 C
 TIP50 = 30 C

 so if my maths are correct, the Q2 mosfet is dissipating around 1.7 W

 my mosfets are not isolated with pads from heatsinks - only a thin layer of thermal grease._

 

Wow, your R8 voltage is very high. Were you having problems getting to 250V before you added the BJT filter section?

 In any case, 332V is quite high. And, as a consequence, there is still 58V on the mosfet. 

 If you have any EZ80s lying around try one of those in one of the PSs and see what the voltages are.


----------



## chobint

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_Here are some new pix of my 'Blue' Bijou...
	

	
	
		
		

		
			



_

 

Looks good 
	

	
	
		
		

		
		
	


	




. Hammond case with custom front plate?

 btw fishski13 if you were still interested, I put in that capacitor switch. It doesn't spark or do anything crazy if I flip the switch with the amp on. However, it can take up to 2 full minutes for the DC on the output to drop below 400mv (which I think is the acceptable range?) In my impatience however, I typically plug in a cheap headset after about 30 sec which drops the DC to 0v almost instantly. Anyway, it works and I'm happy.


----------



## runeight

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_Here are some new pix of my 'Blue' Bijou showing all the updates/mod's that
 I've made since it was built.

 snip 

 Here's what I've done so far:
 Added a separate heater tranny for the PS.
 Regal's mod's.
 Amphead's mod's.
 Choke PS mod, variation 2.
 6H30 gold pin input tubes.
 ECC99 gold pin output tubes.
 EZ81 PS rectifier.
 Auricaps in C3, C4 and C6.
 Changed signal wiring to cryo'ed Vampire (buried under all that shielding).
 Stepped attenuator (50K) from ebay (Taiwan).

 I just installed the stepper yesterday, and now understand the enthusiasm for them. The sum total of all the mod's has produced one fantastic listening experience. It's very detailed and dynamic, yet not at all fatiguing. 

 Thanks, Alex, for all your hard work on this design, and your continued efforts
 in this thread. Thanks, also, to all of you who continue to tweak this great
 design. I finally think I'm done (yah, right!). Now I gotta stop reading this
 forum so I can just enjoy the music.
	

	
	
		
		

		
		
	


	


_

 

That's one heck of a lot of changes funch, but it looks great. But most of all I'm delighted that after all of your work it sounds so good.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Wow, your R8 voltage is very high. Were you having problems getting to 250V before you added the BJT filter section?

 In any case, 332V is quite high. And, as a consequence, there is still 58V on the mosfet. 

 If you have any EZ80s lying around try one of those in one of the PSs and see what the voltages are._

 

no EZ80s lying around.

 no problems dialing in 250V before or after inserting the BJT filter section.


----------



## runeight

OH. OK. You probably didn't need to make this mod. But now that you did, thanks for testing it out. Others can now make the mod if they are having B+ problems. I assume that your amp is still quiet?

 I think you might grab some EZ80s to lower that 332V. Don't want to change the resistor on the BJTs because they are now burning about 1W each and this is enough for your heatsinks.

 I can pretty well guarantee that your B+ will never drop below 250V.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_OH. OK. You probably didn't need to make this mod. But now that you did, thanks for testing it out. Others can now make the mod if they are having B+ problems. I assume that your amp is still quiet?

 I think you might grab some EZ80s to lower that 332V. Don't want to change the resistor on the BJTs because they are now burning about 1W each and this is enough for your heatsinks.

 I can pretty well guarantee that your B+ will never drop below 250V. 
	

	
	
		
		

		
		
	


	


_

 

thanks. i think i will just go back to bog standard and remove the add-on.


----------



## chobint

I can't remember, did you ever get around to doing regal's mod fishski? (trying to entertain the necesity of the mod in conjunction with regal's, etc)


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_I can't remember, did you ever get around to doing regal's mod fishski? (trying to entertain the necesity of the mod in conjunction with regal's, etc)_

 

nope...excellent food for thought.

 runeright,
 can i just add some more heatsink to Q2 and call it good? i understand the error of my maths - the mosfet is still dissipating 4 W.


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_nope...excellent food for thought.

 runeright,
 can i just add some more heatsink to Q2 and call it good? i understand the error of my maths - the mosfet is still dissipating 4 W._

 

Yes, you can do that. But, if you're going to make the regal mod you may want to keep your BJT filter section because it will draw quite a bit more current per channel.


----------



## amphead

Pabbi, you have me worried man. Are you alright?


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, you have me worried man. Are you alright?_

 

hopefully he's stoned out on the fresh tunes.


 performed 10K surgery on the other BJT filter. i think i will order up some resistors for regal's mod in addition to more heat sinks. i'm going to stack another Standard Products Found on top of each existing Q2 heatsink, doubling the size of each - thermal grease in between where they meet.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, you have me worried man. Are you alright?_

 

You know, sometimes electronics takes a wierd turn - to wit, my wife bought a new ceiling light fixture that i had to put up last night - a snappy 2.5 hours. Worse than casework.

 So, I haven't looked any further, trying to think through the current dliemna. The Goldpoint site gives me one hope of how to knock down the gain, but I also simply need more steps in the volume control, so, to drag this out a bit more, I am pondering a combination of the Goldpoint solution (as also recommended ad nauseum by dsavtisk) along with the new Joshua Tree 128 step(per). The other oddities still need looking at (perhaps something shook loose in shipping), but I need a clear head for that.

 Now, since there is plenty of room in the case, JT makes sense.

 Yeah, yeah, going all the way around the mountain to justify a poor initial decision, but, the outcome will still be rather unique.

 Fishki, mayhaps you will have a better outcome, and, solution.

 Edit: And Ron, you did everything you could - this is on me, but what's the fun in no challenges?


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_You know, sometimes electronics takes a wierd turn - to wit, my wife bought a new ceiling light fixture that i had to put up last night - a snappy 2.5 hours. Worse than casework.

 So, I haven't looked any further, trying to think through the current dliemna. The Goldpoint site gives me one hope of how to knock down the gain, but I also simply need more steps in the volume control, so, to drag this out a bit more, I am pondering a combination of the Goldpoint solution (as also recommended ad nauseum by dsavtisk) along with the new Joshua Tree 128 step(per). The other oddities still need looking at (perhaps something shook loose in shipping), but I need a clear head for that.

 Now, since there is plenty of room in the case, JT makes sense.

 Yeah, yeah, going all the way around the mountain to justify a poor initial decision, but, the outcome will still be rather unique.

 Fishki, mayhaps you will have a better outcome, and, solution.

 Edit: And Ron, you did everything you could - this is on me, but what's the fun in no challenges? _

 

i'm going to tackle the attenuators tonight or tomorrow night. i have 2 two deck make-before-break rotaries from Electroswitch http://www.electro-nc.com/rotaryus/d9.pdf.

 i'm going to try a shunt type. i found this schematic which looks pretty simple - and only 2 resistors in the path. diyAudio Forums the downside is that your source will not see the same impedance from click to click on the switch.

 i'm anticipating only needing a total of 20 dB of gain. the trick is, what value should R2 start out at, and how much gain do i want at each step - first couple of positions could have 3-4 dB of gain, and the rest 1-2 dB. i have a bunch of resistor values that i think will work, but experimentation will be necessary. i'm going to try a boutique 100K Caddock or Kiwami for the R I/O, and populate the rest with Vishay RN60 after i get the resistor values worked out.

 here's a cool calculator for determining the amount of attenuation you want.
Stepped Attenuator Resistor String Calculator - Neville Roberts

 this may also be of some interest to you as well.
S5 Attenuator with Sweet Whispers Advise


----------



## holland

pabbi1, perhaps you can turn up the NFB? You can also remove the cathode bypass cap. I can't recall what you've got on your amp right now.

 Another thing you can do, as a temp, till you get your attenuator is to build a cable with an inline cap and take the + line and reference it to ground instead of - . You effectively become single ended, but it's only temporary and should allow you to use your amp.

 Another little thing to try till you get your JT going.

Shunt mod - How to? - World-Designs-Forum


----------



## pabbi1

Yes, everything is pointing me to shunt pot... thanks, all, just gotta figure out which way to go. Sadly, I did not choose the nfb path, so that's out.

 And, let's not forget I couldn't wire up my attenuators in the first place... but, I do like the approach of shunt in the abbreviated sense, but think the Goldpoint solution 







 more elegant, assuming it will work the same with my attenuators. Now we will see what resistors I have close to 90k / 10k - will something boutique help here?


----------



## holland

I would reconsider the NFB 
	

	
	
		
		

		
		
	


	




 You can use a fixed path, it should be easy to add.

 I'm a big fan of using enough gain for your needs. A hot source with a balanced amp can be way too much for any person. I'd guess your source is probably putting out 4-6Vrms? That's a big voltage swing.

 I'm not really a fan of attenuating the source signal to an extreme degree, followed by huge gain in an amp. Less gain, less attenuation, yields finer control with your potentiometer.

 To answer your question, perhaps. Do you believe in boutique resistors? If so, then yes.


----------



## amphead

I think you hit the nail on the head Holland. Pabbi will need to put a fixed NFB resistor in place of an NFB pot, along with the others necessary, and I would be careful to add just enough. Too much NFB is also a very poor sounding solution. Then with the reduced gain, the attenuator can use smaller values, assuming you go with the goldpoints. The intermittent On/Off of the power suggests a short, and I never had that problem. Check the tape that wraps around the heater wiring and make sure it's not allowing the heaters to touch ground there. Edit: the NFB could be tried last, because then all of those boards have to be pulled. You could try the goldpoints with larger resistance first to see if the sound is worthy.


----------



## luvdunhill

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Now we will see what resistors I have close to 90k / 10k - will something boutique help here?_

 

you must support the locals.. they do sell direct, and best resistors out there.

Texas Components - Precision Resistor & Microelectronics


----------



## funch

I had the cage off my amp today, checking the PS voltage. After about an
 hour, I noticed that the 270 DAX was running very warm; enough that I 
 couldn't hold my hand on it for more than a couple seconds. Is this normal, or
 do I need to look at changing to the 370?


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I think you hit the nail on the head Holland. Pabbi will need to put a fixed NFB resistor in place of an NFB pot, along with the others necessary, and I would be careful to add just enough. Too much NFB is also a very poor sounding solution. Then with the reduced gain, the attenuator can use smaller values, assuming you go with the goldpoints. The intermittent On/Off of the power suggests a short, and I never had that problem. Check the tape that wraps around the heater wiring and make sure it's not allowing the heaters to touch ground there. Edit: the NFB could be tried last, because then all of those boards have to be pulled. You could try the goldpoints with larger resistance first to see if the sound is worthy._

 

Yeah, the thought of pulling all the boards was not my idea of a good time, especially if I didn't get the value right the first time - but, adding sockets for resistors has appeal. I was actually just showing the Goldpoint solution for how I was considering rewiring the existing attenuators.

 So, what value would the suggestions be for NFB? Does this mean _changing_ R1 (YUCK!!) or just adding R12 or... ? 

 I'm letting this sit for a day or two - I have some finish work to do on a BH mod...


----------



## amphead

Funch, yes, that is normal. They seem to run very warm. If it is frying egg warm, that would be too much of course. You could try a separate tranny for heaters, to reduce the temp on the PS transformer.

 Pabbi, it will need all of the resistors as shown on Alex's website. The reverse of this:
 * Eliminate the 250kΩ feedback pot(add 125k resistor)
 * Remove (or don't install) R12(install R12)
 * Change R1 from 10kΩ to 300Ω(change R1 to 10K)


----------



## funch

OK, thanks. I'll just leave it alone, unless it goes boom.


----------



## amphead

Chobint, here's the schematic you were looking for.......






 Pabbi, let me know if there is anything I can do to help. I hope that damn intermittent ON/OFF is found. The amp was working so well, I just don't get it.


----------



## chobint

Thanks for the schematic Amphead. As usual my initial guess was wrong, so you must forgive me for asking another question. It appears that the module will be powered by two 9v batteries in series(?). Does that mean, alternatively, that I could use an 18v wallwart? As I mentioned earlier in PM's, the negative voltage thing throws me for a loop.


----------



## amphead

Chobint, if you want to use wallwarts, then it will be two 9 volt supplies. One of the supplies has the positive tied to ground and the other has the negative to ground. The one with positive tied to ground will be connected with the negative tied to pin 11. The one wired "normally" with negative tied to ground will be connected with the positive tied to pin 4. Edit: you can use an 18v wallwart with a voltage divider if you want.


----------



## chobint

makes sense. i will try that. Thanks again


----------



## fishski13

runeright,
 i need help finding an appropriate heatsink for the Q2 mosfet, assuming i decide to leave the multiplier add-on on. i'm not sure that my original idea of stacking another 1.5" Standard Products Found on top of the existing one will work - yes or no? space is tight on the PS board and finding a heatsink with an appropriate thermal "resistance to ambient" is difficult with the space limitations.

 i was wondering if this one would work: Standard Board Level Heat Sinks

 the Tj i calculated is a bit on the high side though, at 89 C :
 Tj= Ta + (P(Rjc+Rcs+Rsa))
 where,
 Ta = 50 C (an assumption based on the fact i was getting 36 C with the chassis cover on, but only one PS board and one EZ81.)
 P = 4 W
 Rjc = 1.79 (Fairchild data sheets - http://www.fairchildsemi.com/ds/FQ/FQP4N50.pdf)
 Rcs = 0 (mosfet not isolated with pads, only thermal paste)
 Rsa = 8

 do my maths look right?

 soldering C3 on the underside of the PS board could free up some space for larger fins as well.

 i'm also considering DIY some custom aluminum heatsinks or trying to mount the Q2 on the underside, mounted directly to the bottom of the chassis.

 thanks!


----------



## fishski13

ooh, ooh... this may work: Wakefield 634 series

Digi-Key - 345-1027-ND (Wakefield - 634-20ABP)

 and scroll down to pg. 15 on the data sheets:
http://www.wakefield.com/PDF/board_level_heat_sink.pdf


----------



## adamus

Spent some time modding the bijou this morning. 

 Socketed r2 for tube rolling. 

 changed output bypass to obbligato films. 

 rolled in some 6n1p EB. 

 I'll let it burn in for some hours and report back.

 maybe its just new tubes that need to break in.... but bass is huge compared to the 6922's.


----------



## adamus

shall i regal mod it? are there any problems with regal modding and using the 6n1p's with 6n6p's?


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_ooh, ooh... this may work: Wakefield 634 series

Digi-Key - 345-1027-ND (Wakefield - 634-20ABP)

 and scroll down to pg. 15 on the data sheets:
http://www.wakefield.com/PDF/board_level_heat_sink.pdf_

 

That looks perfect. I assume you'll use the 637-25ABP - the curves say a heatsink temp rise above ambient of 30C at 4W. This will be good.


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_shall i regal mod it? are there any problems with regal modding and using the 6n1p's with 6n6p's?_

 

The current draw of this combination may pull the voltage down in the PS before the regulator to the point where it drops below 250V. We have seen this before.

 However, if this happens we posted a PS mod a few pages back that fixes this. fishski13 has pioneered testing this mod and we do know that it works.


----------



## adamus

great, i think i will do it next week. Should have done the whole lot whilst i had the amps out. 

 by the way, the 6n1p's make the amp sound more lively, slightly less polite.


----------



## chobint

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_by the way, the 6n1p's make the amp sound more lively, slightly less polite._

 

glad to hear some impressions on tubes. I also found the white amperex 6dj8's to be more punchy and aggressive than the standard jj/sylvania 6922's. I'm looking forward to trying some 6n1p's myself if I ever get around to it.

 on a different note, I will have regal's mod in by the end of the night and I'll try it out with both the jj's and the 6n6p's. My PS seems to have about 15v worth of headroom atm with 6n6p/6dj8/EZ81 combo, so we'll see what happens.


----------



## holland

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_ooh, ooh... this may work: Wakefield 634 series

Digi-Key - 345-1027-ND (Wakefield - 634-20ABP)

 and scroll down to pg. 15 on the data sheets:
http://www.wakefield.com/PDF/board_level_heat_sink.pdf_

 

Digi-Key - HS386-ND (Aavid Thermalloy - 531302B02500G)
531302B02500G

 I use those on my SOHA II. They fit the board outline just fine on the Bijou as well. I will use them on my Bijou as well.

 They "seem" a little better than the Wakefields. I've used both in the past, and I can't say I really notice a difference, but the datasheet shows some.

 Digikey and Mouser only stock the 2.0" Wakefields, but they have the 2.5" Aavids.

 Edit: BTW, the 634s you linked to won't fit the board, but I suppose you can let it dangle and rest on the board. You need the space underneath for convection. The bigger sinks are better (637 or the Aavid).


----------



## chobint

sigh...well scratch that. Just as it is too late to run to parts express for a replacement, my ez81 is blowing fuses left and right and arcing internally so I'm back to ez80 for now. No mods till monday. I'm a sad panda 
	

	
	
		
		

		
			




 edit: I need to shoot that black cat outside of my house or something. My JJ 6922 just lost one of its pins while swapping tubes


----------



## funch

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Chobint, here's the schematic you were looking for.......






 Pabbi, let me know if there is anything I can do to help. I hope that damn intermittent ON/OFF is found. The amp was working so well, I just don't get it._

 

Check out message #121.
HeadWize: DIY Workshop > β22: A discrete, cascoded, fully complementary, pure class A amplifier (part 3)


----------



## fishski13

runeright and holland,
 thanks guys! i've removed the internal divider between the transfos and PS boards to free up some air movement. with the divider in place, the PS boards are effectively in a partitioned "chamber". i'm going to keep the BJT multipliers - i sacrificed a $12 EZ81 to get it operational damn it 
	

	
	
		
		

		
		
	


	




.

 chobint,
 i feel your pain - losing a tube is a real bummer. the arching noise is a bit unsettling as well.


----------



## amphead

Thanks Funch, yeah that's a good way to listen to a balanced amplifier in unbalanced/SE mode.

 Chobint, sorry to hear about those tubes.

 Well, I had to do some roadie work for my nephew Saturday. I Put some ear protection in for the show. 

 My nephew on the right......






 The drummer.......


----------



## adamus

drummer looks like he could do some damage! 

 I have been pulling tubes in out out to get a good picture of the differences. 

 The is no contest, the 6n1p wins on detail, bass (tuneful..its tightened up no end since intitial testing), soundstage. to my ears its all round a better experience. Quiet strange really, looking at the datasheet the point we are operating at is more linear with the 6922s.


----------



## rhys h

How would i use a meter such as this

100mA mA meter for BIAS 300B 2A3 6L6 EL34 6550 Tube Amp - eBay (item 250321873157 end time Nov-14-08 19:40:38 PST)

 With the bijou to measure bias?

 Looks an intresting idea.


----------



## pabbi1

Parts inbound, so I'll start the procedure tomorrow evening - where I have Phoenix connectors, do I just screw in the NFB resistor? Guess I need to fill out where I only had some 2 position connectors to cover the 3 holes, since I was never going to need NFB...


----------



## amphead

rhys h, there is an alternative to using that meter. You would solder a 1ohm 1w resistor in series with the tube cathode you want to measure to ground and put a 100mv scale meter across the 1 ohm resistor. Then 1mv=1ma of bias current(V/R=I and 1mv/1ohm = 1ma). Remember that you will be measuring the bias of an individual tube, and there are 5 tubes, in a single ended Bijou all fixed biased with their individual resistors.

 Pabbi, once you have installed the 3 position phoenix, it is a simple procedure of just cutting the resistor leads and bending them to fit and tightening down with the connections. This allows you to experiment with different values to find what sounds right to you.


----------



## chobint

blah...so my brand spanking new ECC99's are drawing more current than my 6n6p's, which is the opposite of what's supposed to happen right?

 Readings taken with the PSU pot in the same position (somewhere in the middle):

 EZ81/6n6p -
 R8 - 315.5v
 R7 - 278v
 B+ - 256v

 EZ81/ECC99
 R8 - 306v
 R7 - 263v
 B+ - 250.8

 EZ80/ECC99 combo also proves unable to give 250V @ B+. The reading seem to indicate that the ECC99's are actually drawing the EZ81 PSU below the intended operating points?? Any reasonable explanations for such behavior, or should I be sending these back for a new pair?
 edit: this is the the boards setup in stock config


----------



## runeight

chobint we have seen that there are a few ecc99s that seem to operate on the high end of their range.

 But, with the EZ81s you are seeing at least 13V above 250V with the ecc99s. This is plenty of headroom for the regulator.

 If your PS continues to work like this you won't have any problems.

 However, are you planning the regal mod? If so, then the add-on BJT board will be the only solution to low B+.


----------



## fishski13

finally wired up all 4 amp boards - i'm taking a break before i flip the switch. i've place an order to Digikey for new heatsinks and male XLR connectors. the K701 will be the first to go under the knife for balanced operation. i'm glad i only "tagged" those Q2 heat sink pins in with solder. i'm getting rammy.


----------



## chobint

Thanks Alex. I went ahead with the mod and go figure, EZ81/6n6p/6922 /w regal mod is easily regulating 250v B+. R8 305v, R7 267v. I think someone (adamus I think?) was wondering if this combo would work? Apparently it can if your PS has enough headroom. As for sound, it seems punchier but then again I'm a strong believer in the placebo effect so...

 And I second the opinion that the sextetts sound good with this amp...I won't be ditching my old phones but these will probly be on my head for the next week or so.


----------



## aneee

Hi guys,I'm looking for make a Bijou (my first DIY) and I have many problem with my setup.If I use 6H23P Xoviet for the input stage,R2 will be change how ? And why sbd make their Bijou go balanced (headphone too),what is the advantage ? btw sorry for my poor English...


----------



## amphead

Aneee, I believe the 6N1P are superior in sound quality to the 6H23P. That is the least of your problems, in choosing the Bijou as a "first" diy project. The Bijou contains HIGH VOLTAGE, in excess of 330 volts dc and the chance exists that you will be electrocuted without sufficient knowledge of this type of circuit. Having warned you of what can happen however, you could work your way up to the Bijou, by building easier amplifiers first. If you have a friend/associate who is experienced in High Voltage, maybe they could mentor you until you get enough experience. Good Luck! Edit: if you have already started to build the Bijou then, we will try to help you with your questions.


----------



## aneee

Thx Amphead, I don't have any exp. in diy and electronic but I really want to make it (I research it about 2 week and then). I will be careful with the High Voltage and going to make step by step, I hope that I can make my first project with your help :d so I intend to make my Bijou with Regal 's mod(amp schematic) and your mod(PS schematic), are there any problem in that ?


----------



## amphead

Well, it would certainly not be easy for one to learn to solder, while avoiding an electric shock from powerful capacitors, some of which store a dangerous charge long after the amplifier is powered off. I would not say it is impossible to build, but an extreme challenge with some hazard associated with it for the inexperienced.


----------



## Dantes

Hi there, i wome back for some advise.
 I would like to make the regal mod but here in france i can't find 30k 2w resistor. there is 33k and 27K.

 can i use one of theses 2 or have i to use 2x15k ?


----------



## runeight

Dantes, it would be best if you can use 30k somehow. Two 15k in series will do just fine.


----------



## Dantes

so, let's doing the regal's mod.


----------



## pabbi1

OK, all - she lives, perfectly usable and quite lovely. Mind you, it has only been powered up 20 minutes, and I'm slapping her around with some Drowning Pool...

 Took the long way home, replacing the r1 with a 10k, and r12 with the same, then 124k on the NFB - almost dead perfect, as I am playing pretty loud at 11 o'clock.

 I am catching some occasional 'scratchiness' (almost a static) on the right channel - just occasionally, and not bad, but noticeable - probably a connection issue - I'll audit later - for now I want to hear what it can do in general. May be one of the NFB resistor connections not connected as well as it ought to be.

 Definitely NOT bass shy, but lush, not in a sluggish way either. 

 Pictures later...

 And, big gracias to Ron... bailing me out again, but it is now off to electrostat ladyland, as a new design awaits - at least I can listen to the Bijou as I design (case) / build (other folks design).


----------



## fishski13

congrats!

 sounds like it could be a bad tube.


----------



## pabbi1

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_congrats!

 sounds like it could be a bad tube._

 

Maybe - good thing I have 20 (extra) of each - all 6n1p and 6n6p...

 Look, I admit FOTM, and psychoacoustics are all in full affect, but I am hearing imaging through the 650s I have never heard in any dynamic (vocal imaging in the studio is unreal, the speed and seperation is dang near 'stat like)... of course, I need to run through a full range of material, but 'Paranoid Android', 'Creep' and 'No Surprises' just knocked me out - no tko either.

 Sometimes you take a shot, and a lot of abuse ('Why do you always do balanced?") - well, you can hear why. 

 Fishski, you are in for a treat, if your results are anything like mine.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Maybe - good thing I have 20 (extra) of each - all 6n1p and 6n6p...

 Look, I admit FOTM, and psychoacoustics are all in full affect, but I am hearing imaging through the 650s I have never heard in any dynamic (vocal imaging in the studio is unreal, the speed and seperation is dang near 'stat like)... of course, I need to run through a full range of material, but 'Paranoid Android', 'Creep' and 'No Surprises' just knocked me out - no tko either.

 Sometimes you take a shot, and a lot of abuse ('Why do you always do balanced?") - well, you can hear why. 

 Fishski, you are in for a treat, if your results are anything like mine._

 

thanks. new heatsinks and XLRs arrived today. worked on an attenuator last night. all 4 amp/2 PS boards are fired up and working, although i need to rip out the PS boards (again) to get the new heatsinks in. i'm off for the next week after tonight, so should have music in a few days.

 yes, this has turned out to be quite the project, and i don't even have the attenuators done.


----------



## pabbi1

Oh, and plenty of the photoflash caps left - if anyone has NOT gotten theirs, that was expecting some, PM me.


----------



## amphead

That's fantastic Pabbi! Yes, Fishski is in for a real treat. There is just that magic pixie dust all over the sound with the Bijou in balanced mode. I have to wire my K701's for balanced operation, since my next project is to do the Bijou in balanced mode. A little tricky to do the phones, but a cautious approach should do the trick. Pabbi, just put me on the lowest tier of membership here and we are square for shipping. You will notice that it gets quite warm after long 4 hour sessions, but the trafo just keeps on tickin.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_That's fantastic Pabbi! Yes, Fishski is in for a real treat. There is just that magic pixie dust all over the sound with the Bijou in balanced mode. I have to wire my K701's for balanced operation, since my next project is to do the Bijou in balanced mode. A little tricky to do the phones, but a cautious approach should do the trick. Pabbi, just put me on the lowest tier of membership here and we are square for shipping. You will notice that it gets quite warm after long 4 hour sessions, but the trafo just keeps on tickin. _

 

i like pixie dust.

 i was planning on removing the center grill on the outer K701 housing to view the color of the wires for each channel before snipping and terminating with XLRs. any other recommendations? i'm sticking with single entry and stock cable. i have yet to order the Senn connector for the HD650.

 i can't wait to see what you come up with for your balanced Bijou.


----------



## fishski13

got the new heat sinks in without a problem - i do have to say though, these PCB are tough. i've delsodered more than a few pieces now, re-soldered a few more than that, de-mounting and re-mounting each time, and poked and prodded with probes and alligator clips. nary a scratch. 

 temps seem o.k. with the top on the amp, underneath a 300W halgen 2 ft above - and i can hold my hand on the top of the amp without issue 
	

	
	
		
		

		
			





.

 i listen to the 2 new amp boards, un-balanced, with one of my "experimental" attenuators, and iPod earbuds. i only have 5 clicks soldered. i will do the other one tomorrow, and maybe attempt to re-wire my K701 balanced. i've decided to use a 4-pin XLR. 

 i am also a bit concerned about getting enough gain with only 23 positions for un-balanced headphones. i was just planning on wiring for balanced and unbalanced operation a la AMB's B22 method. will the balanced output have that much more dB gain than un-balanced??? thoughts, anyone???

 cranked up my superstitiously good-luck ablum, The Replacements - Pleased to Meet Me (arguably the greatest rock and roll band of all time). on the 3rd click, the right channel of my earpuds nearly exploded. ouch, that hurt. further investigation revealed a 475*K* resitor in the place of an intended 475 ohms. 
	

	
	
		
		

		
		
	


	







 ha ha...yeeeeha


----------



## Dantes

Some news of my bijou, working with the regal mod.

 The PS board use an EZ81.

 With the 2 6DJ8/ECC88 Tubegeneral electric, no problem, B+ at 250V without problem.
 Theses tubes are very detailled, too detailled.
 They have a lack of bass and the highs are aggressive.
 My headphone is know to be clear (beyer dt 911) so it's not very good... ans the bass is embarrassing.

 With 2 6922 philips, B+ is at 242 V max.
 There probleme, a lack of highs and seems veil.
 Inded the regal's mod remove a part of it and now they sound fine... but with a lack of detail.


 But on theses 2 pairs of tubes, 1 tube is microphonic. i have to make or buy some dampers.

 The other pair of tubes is made with two 6N6Pi


----------



## pabbi1

Well, the end is in sight... the 'scratchiness' is a loose tube, that gets bumped occasionally, and with the tube dampers, it is absolutely quiet, other than signal.

 First, some pron:

 [
	

	
	
		
		

		
		
	


	



 and, with a top, for the protection of my beasties. Edit: Pretty wire, and Amphead mod is attributable to Amphead - without whom, this story does not have a happy ending.






 It may well be true that a balanced beta22 is the detail king, but the presentation of this amp misses no details I can detect. With the 6nip and 6n6p, there is a wee too much bass with the hd650, and just darn near perfect with the hd600. I am hearing great presentation, where even the slightest detail is being pushed out - and yet, without straining - the music just flows. 

 I am going to have some folks over in the next few weeks, and maybe all the edges will be worked in by then, but I also want the signature established before doing critical comparisons - but, I am a happy camper.

 Now to get a proper wood front panel, and paint for the back / sides, and this one is wrapped up.


----------



## fishski13

jesus, that looks great. can't wait for the finishing touches. 

 i performed some surgery on the K701 for balanced. i think i have it wired correctly 
	

	
	
		
		

		
		
	


	




 (no replies yet to my thread). i also finished the other "rough" attenuator, with 5 clicks only. i should be listening in balanced sometime tomorrow!


----------



## amphead

If you get your K701's working in balanced mode Fishski, I will be taking notes.

 Pabbi, I enjoyed the listening while it lasted, but it is good, as well as surreal to see it from the other side of the magic screen.  If it is used for more than 4 hours straight, check on the temp, now that it has a cover.


----------



## chobint

Connecting the Balanced Cable
 ===================
 The wiring scheme for the AKG K701 is:

 orange = right +
 white = right -
 yellow = left +
 black = left -

 quoted from: http://www.head-fi.org/forums/f6/gui...abling-225819/


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Connecting the Balanced Cable
 ===================
 The wiring scheme for the AKG K701 is:

 orange = right +
 white = right -
 yellow = left +
 black = left -

 quoted from: http://www.head-fi.org/forums/f6/gui...abling-225819/_

 

yes, but nmahr posted later in that thread that the grounds were switched on his pair, and i believe mine are as well.

 please see my thread: http://www.head-fi.org/forums/f6/nee...lanced-381413/

 i took measurements across the L and R +/- of my HD650, and i'm getting approx. the rated nominal impedance, 275 ohms. on the K701, i'm getting 60 ohms across yellow/white and orange/ground - i get mega ohms when the grounds are switched. any thoughts???


----------



## huskydawg9

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_OK, all - she lives, perfectly usable and quite lovely. Mind you, it has only been powered up 20 minutes, and I'm slapping her around with some Drowning Pool...

 Took the long way home, replacing the r1 with a 10k, and r12 with the same, then 124k on the NFB - almost dead perfect, as I am playing pretty loud at 11 o'clock.

 I am catching some occasional 'scratchiness' (almost a static) on the right channel - just occasionally, and not bad, but noticeable - probably a connection issue - I'll audit later - for now I want to hear what it can do in general. May be one of the NFB resistor connections not connected as well as it ought to be.

 Definitely NOT bass shy, but lush, not in a sluggish way either. 

 Pictures later...

 And, big gracias to Ron... bailing me out again, but it is now off to electrostat ladyland, as a new design awaits - at least I can listen to the Bijou as I design (case) / build (other folks design)._

 

Please include in your review, the power trio from Canada... Rush... specifically.. from Hemispheres, La Villa Strangiato. This song absolutely kicks butt in my SE version. If you need it...ask me.


----------



## pabbi1

Funny, you should mention that - oh, and shoot me your addy for the caps...

 Working my way through countries - firmly stuck in Australia atm, with Jett / AC / DC / & The Hives... oops, they're Scandanavian - no real difference...

 A short detour - on Jett's 'Last Chance' there is a guitar line starting off by both guitarists, in 2 part harmony, which on less resolving systems sounds like just one distorted guitar part - sneaky, cynical, or brilliant that musicians write bits that sound good / better / best as the resolution increases. There is also a background clapping keeping time all the way through - I could tell this was more than one person clapping along, but NEVER able to place the distinct location of each, much less the differentation of each person's clap. That, folks, is a specific example here of what Ron refers to as 'pixie dust'. Brute force to reproduce everything in the music - and the challenge is to let go of how we remember other presentations of the music.

 Or, simply learning the signature of this amp. - Which makes me wonder - has anyone noticed the bass in this amp? Maybe other amps can't reproduce bass well, and engineers pump it up a bit, but this amp has bass, along with PRaT.

 RE: Rush - I have two pieces of theirs - one is a Greatest hits, and the other is 'Exit... Stage Left', with Strangiato... alas, but live... and neither have 'Train to Bankok'... but the first has 'Working Man'... cueing in about 20 minutes.

 Then it is off to Lynyrd Skynyrd to see if I can tell the Firebird V from the Firebird VII... 
	

	
	
		
		

		
		
	


	




 Edit: I NEVER knew Freddie Mercury had a lisp - but I heard it all over Queen's Greatest Hits, and thought it was an op amp slurring, or crappy recording - amazing.


----------



## holland

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_oops, they're Scandanavian - no real difference..._

 

LOL. I had to do a double take on that. I think I got what you meant, which is not what I quoted. 
	

	
	
		
		

		
		
	


	




 What case are you using, pabbi1? That's not the NABU, right?


----------



## pabbi1

No, the Nabu was just too small - this is a Navy surplus case, same as I used for the BH, @ 17" square... an eBay find, that was 2 for $40 shipped. Wish I could find more, as I am sure there are hundreds / thousands being scrapped somewhere, maybe all reclaimed due to the price of aluminum.

 Tranny cover is a bolt-on from vt4c.com


----------



## fishski13

pabbi1, you're spot on. i'll post more impressions later. i'm off to listen to more tunes via my balanced Bijou.

 amphead, you've got a PM.


----------



## amphead

Congrats Fishski! Any background noise when music is paused? Thanks for the K701 balanced mod info.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Congrats Fishski! Any background noise when music is paused? Thanks for the K701 balanced mod info._

 

absolutely no noise, dead silent, and no shielded wiring anywhere...but with one caveat; my max volume on my attenuator, temporarily soldered with only 5 clicks of rotation, equals about 75 dB output from the headphones. i'll have a better idea when i solder in the rest of the 18 clicks in. i'll try turning the attenuator to an open step tomorrow. this will give me maxium gain/minimum attenuation based on a shunt-type, and allow me to better assess the background noise. i'll get back to you. 

 i only went with 5 clicks short term to evaluate how much total attenuation i wanted, and didn't want to crank out all that work that might have ended in a total re-build if i mis-judged the resistor values. i will be placing an order to Mouser tomorrow for all (92 total) Vishay RN60 ground-shunt resistors i now know i need. i'm currently jibbing on the net for some 100K Caddocks for the input resistors (4 total), one for each leg of the balanced signal. i'll probably order up some wanky wire for signal wiring to boot. i'm still waiting for my knobs from Taiwan. i'm temporarily forced to use a Vise-grips to rotate the attenuators a la Red Green. grrr...

 i think i'll head-off to Jamaica for the rest of the night and chill with some King Tubby (he's my avatar after-all)
	

	
	
		
		

		
			





. now if only i can figure out how to land this space shuttle...


----------



## adamus

pabbi, the build looks excellent. I would suggest you buy somethign to finish the holes with (for the valves). I used a dismantled valve protector:






 Also, the rectifiers kick out a huge amount of heat, If you can raise them our of the case heat doesnt become an issue. I used some 'socket savers' - they look like socket extenders. They are fine for the rectifiers, not sure i would want to use them on signal tubes. Thsi isnt shown in the picture above, bu the recitifer is now the same height as the output valves.


----------



## fordgtlover

Just swapped my Amperex 6922 out for a set of 6N1P. I am impressed. Given that nice 6922 can be quite expensive and the 6N1P cost a few dollars each, I'd say they are are bargain.

 I also swapped C3 & C4 from the WIMA MKP to a set of Vishay MKT1822 after reading about how some people were much more impressed with the Vishays over WIMA in other amps. The Vishays sound much grainier. I also have a set of Panasonic ECQ polypropelene, which I think will be going in sooner than I'd originally expected.


----------



## adamus

completely agree on the 61np front. They give it so much more attack, it actually works on rock music now! 

 The obbligato bypass caps have made a nice improvement to the sound, certainly cleaned the high end up, but the cake was the 6n1p, the icing is the bypass cap. 

 I have to Regal mod mine next.


----------



## pabbi1

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_pabbi, the build looks excellent. I would suggest you buy somethign to finish the holes with (for the valves). <snip>

 Also, the rectifiers kick out a huge amount of heat, If you can raise them our of the case heat doesnt become an issue. I used some 'socket savers' - they look like socket extenders. They are fine for the rectifiers, not sure i would want to use them on signal tubes. Thsi isnt shown in the picture above, bu the recitifer is now the same height as the output valves._

 

Yes, I have taken that approach on the BH (look at my 'modded' link, but it has been cleaned up a bit from there). With all the cross ventilation, I haven't found heat to be an issue. I have some of the machined tube surrounds handy, but have chosen not to use them, as this build just isn't bling to me.

 Alas, there is still some occasional background static - not tubes, so it may be the sockets or one suspect wonky rled resistor (don't ask). Ok, so I'll confess - I did snip a rled lead in error when trading out r1, but soldered it back together - is that a suspect? Since this is intermittent, i think connections, so, I'll pull all the tubes, deox again, and get out the silver contact stuff, since I have gone over and over all the other connections. 

 It also seems worst after several hours - heat, perhaps? This is definitely the no fun part of DIY.


----------



## adamus

could be a tube going south? have you swapped them around -bit of hassle as it could be of 4.

 For those that are enjoying the 6n1p's (which i certainly am). have a look here: http://www.mif.pg.gda.pl/homepages/f...3/6/6N1PEV.pdf

 basically we are in the most unlinear operating mode you can get....question is why do they sound so good???


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_basically we are in the most unlinear operating mode you can get....question is why do they sound so good???_

 

This is because the human ear likes the sound of tube non-linearities so long as they don't get too large.


----------



## amphead

Pabbi, take your time and attack it with a modular approach. Pull only one board at a time and reflow all of your solder joints. You could try replacing tubes in a modular approach as well, such as all different tubes on one board and staying with that for 24 hours. Then move to another board, this way you will eliminate it as an issue. Just use different tubes, and keep track of where they are. Make a checklist and put a check next to what has been done, to help keep track. Edit: an unrelated item to do is check the B+ for 250vdc. Also, I am suspicious of the attenuators as a source of noise, but it is just a gut feeling. If there is a borderline solder joint on any of the individual resistors on the attenuators, that could cause intermittent noise.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, take your time and attack it with a modular approach. Pull only one board at a time and reflow all of your solder joints. You could try replacing tubes in a modular approach as well, such as all different tubes on one board and staying with that for 24 hours. Then move to another board, this way you will eliminate it as an issue. Just use different tubes, and keep track of where they are. Make a checklist and put a check next to what has been done, to help keep track. Edit: an unrelated item to do is check the B+ for 250vdc. Also, I am suspicious of the attenuators as a source of noise, but it is just a gut feeling. If there is a borderline solder joint on any of the individual resistors on the attenuators, that could cause intermittent noise._

 

I am also suspicious of the attenuators, because the sound is VERRRRY similar to the scratchiness you hear with a scratchy pot. Again, just a gut feel, but like deja vu all over again. But, you do bring excellent advice to attack the issue systematically...

 Now, where is that Bijou line art from about 800 posts back?


----------



## fishski13

i agree with Amphead re: the attenuator. if your tabs are anything like what i have on my Electroswitch (i.e. you could easily fit 5 resistor leads in each tab hole), if you haven't already done this, it would be a good idea to be more liberal in the amount of solder you use, and especially if you have any stranded wiring as apart of the attenuator design. both the large attenuator tabs, and stranded wire, tend to suck up a bit more of the solder than let's say a tab/hole on a PCB. i could easily see a situation where a solder joint could have become weakened in shipping. building an attenuator is essentially P2P - a little more solder is a good thing.


----------



## fishski13

amphead,
 with no attenuation, and my source on pause, i get a faint, airy, white-noise or static, and a faint buzz in the L channel only. 

 if i touch the input wires to the amp boards from the attenuator, the static becomes a little louder. these wires are not twisted together. 

 touching the input wires from the chassis XLR male recepticles to the attenuator has no effect on the level of static - but these are tightly twisted.

 my signal wiring is a total rats nest. i didn't bother too much as i knew i was going to be re-doing it with some wanky wire anyway. 

 also, i have yet to ground my attenuators to star-ground - they're mounted on an acrylic faceplate. the static also increases in volume when i touch them, especially with my Vise-grips. i may get around to doing this tonight or tomorrow.

 again, i have not shielded any wiring. i also have a dedicated AC line to a breaker box directly underneath the hi-fi room.

 i'm not terribly worried about this. you should hear the amount of noise out of a Naim amp/speaker combo standing 8 ft away, and even with max attenuation. i lived with an all Naim hi-fi for 5 years. it's been absolutely dead silent thus far at the amount of attenuation i have now. we'll see what cutting another 10 dB of attenuation will do to the background noise when i get the rest of my resistors soldered in.

 thus far with the K701, this is the most detailed hi-fi i've ever heard, especially if transients and a shimmering/stat-like top end is your bag. i also wonder how much more room there is for burn-in.


----------



## chobint

Hey pabbi, I have had a similar problem. After the amp has been in operation for a few hours, one of the channels will start to develop a staticy rushing noise. I say rushing because the noise oscillates in volume like rushing water. If I turned off the amp for a minute and restarted it, the sound would be gone and the amp would play fine for a few more hours. In my case, the static followed the tube when I swapped it around, so I knew it was a bad one. Just thought I'd throw that in there in case the shoe fits.


----------



## fishski13

o.k., i tried a few things, and all with no attenuation:

 - alligator clipped in some ground wires from each attenuator body to star-ground. static/white noise now nearly inaudible - very, very faint.

 - faint buzzing still in L channel, even after switching around tubes systematically, even the rectifiers.

 -the LED pads on the boards have Molex connectors soldered, allowing easy swapping of LEDs. i attached a blue LED, with a 6" twisted wire legs, into the Molex socket of the L- board; the same quality of buzzing got much worse no matter where i moved the wire. switched the LED to the R- board and got a new, buzz in that channel that was not there before. the L channel buzz went back to its original quiet faintness with this swap.

 sounds like i could try some shielding on the L channel heaters???


----------



## pabbi1

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Hey pabbi, I have had a similar problem. After the amp has been in operation for a few hours, one of the channels will start to develop a staticy rushing noise. I say rushing because the noise oscillates in volume like rushing water. If I turned off the amp for a minute and restarted it, the sound would be gone and the amp would play fine for a few more hours. In my case, the static followed the tube when I swapped it around, so I knew it was a bad one. Just thought I'd throw that in there in case the shoe fits._

 

There is my problem - even when I change out tubes, it stays on one side, and not the side I suspected. Sounds like I'll reflow some solder this weekend. In the mean time, since it only pops up occasionally, I'll just keep burning things in, and enjoying the music. I have never heard better treble extension on a dynamic amp, and the bass seems to be settling down (maybe burning in the Obligatos). I am continually amazed at how balanced this amp is among the instruments, at how well the entire spectrum is presented. Huge soundstage, with excellent placement

 Oh, and how really well recorded material is rewarded, and crappy songs sound, well, crappy. She is stunningly honest, presenting things cleanly that I have often heard 'smeared'. Snappy is also a good term, especially on percussion, where I can clearly make out the snare vs the mounted toms - and real attack, shimmer and decay on cymbals.

 Ok, I'll refrain on listening impressions - though at some point I'll have to weigh in on Skylab's observations.


----------



## amphead

OK, Pabbi, just take it slow since you are able to enjoy it between investigative work. 

 Fishski, if you did the ground mod, don't bother trying to shield the heater wiring. Just run shielded wire on input signal wiring and ground wires to star ground where ever they make a positive impact. I wouldn't worry about background noise for the highest volume levels, but only the volume range that you prefer for listening.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_OK, Pabbi, just take it slow since you are able to enjoy it between investigative work. 

 Fishski, if you did the ground mod, don't bother trying to shield the heater wiring. Just run shielded wire on input signal wiring and ground wires to star ground where ever they make a positive impact. I wouldn't worry about background noise for the highest volume levels, but only the volume range that you prefer for listening._

 

thanks!!! just what i wanted to hear. and yes, i'm using your mod.

 pabbi1,
 i agree about the bass settling down - i'm using Sonicap GenI on C3,4,6. the mid-bass was a bit overblown in the first 12 hrs. after 24 hrs, the mid-bass is tight and punchy. brand new tubes too.

 yes, very revealing of recording flaws. i never knew how much my electronica collection contained beats/samples that were recorded from vinyl - you hear every tick and pop - but never harsh or overbearing mind you. tape hiss is really pronounced too. i hasn't annoyed me yet.

 the balanced Bijou has the famed Naim PRaT in spades - the music just flows effortlessly. this is one fun, dynamic amp - even partnered the "lifeless/sterile" K701 and Benchmark DAC1.


----------



## AudioCats

one question (the answer probably can be found somewhere in this thread, but it is a bit too big to search now....): how critical is the C1? I suppose it is a feedback cap, does it need to be film? BlackGate NX?

 Thanks


----------



## Ferrari

Quote:


  Originally Posted by *AudioCats* /img/forum/go_quote.gif 
_one question (the answer probably can be found somewhere in this thread, but it is a bit too big to search now....): how critical is the C1? I suppose it is a feedback cap, does it need to be film? BlackGate NX?

 Thanks_

 

A MKP film cap is indeed better than ordinary elctrolytic cap in this feedback circuit.
 Some creative leads bending will be required however. Be sure that the cap is rated at at least 160V.
 BlackGate NX is not applicable at high voltage (>160V)!


----------



## pabbi1

Ok, I get the 'static' sooner now (trending worse), even with the attenuators at minimum (turned all the way down) - does this help isolate the problem to attenuators, and NOT amp boards?


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Ok, I get the 'static' sooner now (trending worse), even with the attenuators at minimum (turned all the way down) - does this help isolate the problem to attenuators, and NOT amp boards?_

 

do you have a couple of pots to wire in instead?


----------



## pabbi1

Not yet...


----------



## holland

change the pot wiring, swap left and right. Since you say the problem might be the pot and it's only one channel, if it's the pot, it'll move when you rewire.


----------



## runeight

Before you do anything else, short each board's In terminal to its In G terminal. If the noise is still there it's on one or more boards. If it's gone it's coming from before the boards.

 If it's coming from before the boards remove the jumpers one at a time and listen for the noise. If you don't hear anything put that jumper back and remove another one until you hear the problem. When you do you can at least identify which attenuator it's coming from.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Before you do anything else, short each board's In terminal to its In G terminal. If the noise is still there it's on one or more boards. If it's gone it's coming from before the boards.

 If it's coming from before the boards remove the jumpers one at a time and listen for the noise. If you don't hear anything put that jumper back and remove another one until you hear the problem. When you do you can at least identify which attenuator it's coming from._

 

yes, shorting IN/ING isolated my crappy pot as the source as while back. good luck pabbi1. 

 balanced bijou + K701 = the largest soundstage i've ever heard. it extends around the back as well on some recordings. electronica is amazing.


----------



## pabbi1

Since you brought that up, I definitely get the sense that a lot of the soundstage is behind me, and on some songs, it is all behind me - anyone else experience that, or, is it something wired wonky?


----------



## runeight

Have you checked that the phasing is the same for both channels? That is L+ and L- should go to O+ and O- on the left channel. And then similar for the right channel.


----------



## adamus

Runeight, I blame you and your bijou entirely for getting me into valves. 

 I have just spent £266 on parts for a speaker amp.

 your fault.


----------



## runeight

I accept full responsibility. 
	

	
	
		
		

		
		
	


	




 However, you should have waited for my very unique hybrid power amp coming sometime next year.


----------



## adamus

I am building a push pull el84 stereo amp, specifically going to do a version of the 'baby huey' design that is floating around. 

 most of the cost is the iron! tranformers are so expensive. 

 I'll look forward to your design, drop me a pm if you want prototypers when the time comes...


----------



## bhjazz

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Have you checked that the phasing is the same for both channels?_

 

That would be my vote as well. Phase errors definitely have a distinct sound to them!

  Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Runeight, I blame you and your bijou entirely for getting me into valves._

 

Cool! Can't wait to get mine started. Nothing but great reviews for it here. Geez, I may not even want to work on anything for a long time...


----------



## amphead

Hope that's it. I was at a slight disadvantage, using the converter. If I had Pabbi's source it would have been easier. But just way too crazy and expensive to do.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Have you checked that the phasing is the same for both channels? That is L+ and L- should go to O+ and O- on the left channel. And then similar for the right channel._


----------



## fishski13

will running the bijou balanced offer more current delivery to the balanced K701? how about with respect to the BJT multipliers i have?


----------



## amphead

I forget what the specification is for a balanced Bijou, but undoubtedly 4 channels produces more power than 2. Therefore, I would expect more current to be available from the output stage. I will leave the rest for Runeight to answer.


----------



## pabbi1

OK, 3 solid hours of listening tonight, and no static whatsoever. Yesterday it was after about 20 minutes... go figure. And, no hints of out of phase - just wonderful goodness. With not so much as pulling off the cover difference.

 Gotta love this hobby.

 Edit: Dry, heated air, and static? Now, this is crazy, but the heater was on last night pretty consistently, but not so tonight - and mayhaps me touching the knobs / pots touched it off, so to speak? Everything is grounded via the IEC, so, surely static electricity is not a factor?


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_will running the bijou balanced offer more current delivery to the balanced K701? how about with respect to the BJT multipliers i have?_

 

Normally this would be true, but the current output of each single ended amp is limited by the O/P triodes going to positive grid. The SE version can drive the headphones to this limit and so the balanced version cannot drive beyond this limit to make quadruple the power.

 If the O/P stages were not current limited by positive grid conditions then indeed the balanced version would quadruple the power output.


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_OK, 3 solid hours of listening tonight, and no static whatsoever. Yesterday it was after about 20 minutes... go figure. And, no hints of out of phase - just wonderful goodness. With not so much as pulling off the cover difference.

 Gotta love this hobby.

 Edit: Dry, heated air, and static? Now, this is crazy, but the heater was on last night pretty consistently, but not so tonight - and mayhaps me touching the knobs / pots touched it off, so to speak? Everything is grounded via the IEC, so, surely static electricity is not a factor?_

 

Probably not static electricity if everything is grounded to metal. I'm still wondering about tube pins and sockets. This almost always what causes this kind of noise for me.

 What kind of music are you listening to now?


----------



## fishski13

thanks runeight.

 pabbi1, have you tried shorting IN to IN Ground yet?


----------



## pabbi1

No, I was trying to induce the static sound first before shorting, since the problem wasn't there to test.

 Listening to the same thing as yesterday - 'Sticky Fingers' (Rolling Stones, with lots of distortion and sound saturation), but crystal clear tonight. Then Radiohead, Hoobastank and Rhianna.

 Tubes are still a suspect, or the sockets, as one fits rather less tightly than the others. I did deoxit all the tubes, and apply some quicksilver to help solidify the contacts, but I can't tell that it made any difference one way or the other. So far, it seems random. Next I'll short IN and ING when I hear it, but hard to believe attenuators at this point. So, I'll go after systematically changing out tubes - any a more likely suspect than the other? That is the only 'interesting' thing about Russian surplus tubes - none known better than others, but I guess they can be run through the tube tester, huh?

 In the mean time, the amp continues to impress. Just beautiful to listen to.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_No, I was trying to induce the static sound first before shorting, since the problem wasn't there to test.

 Listening to the same thing as yesterday - 'Sticky Fingers' (Rolling Stones, with lots of distortion and sound saturation), but crystal clear tonight. Then Radiohead, Hoobastank and Rhianna.

 Tubes are still a suspect, or the sockets, as one fits rather less tightly than the others. I did deoxit all the tubes, and apply some quicksilver to help solidify the contacts, but I can't tell that it made any difference one way or the other. So far, it seems random. Next I'll short IN and ING when I hear it, but hard to believe attenuators at this point. So, I'll go after systematically changing out tubes - any a more likely suspect than the other? That is the only 'interesting' thing about Russian surplus tubes - none known better than others, but I guess they can be run through the tube tester, huh?

 In the mean time, the amp continues to impress. Just beautiful to listen to._

 

good to hear. hopfully it's only a socket or pin that is now clean. 

 i hope to have the rest of my resistors on Mon. to complete my attenuators, and another XLR to balance my HD650. right now, i only have enough gain for albums that are mastered "hotter". 

 the air and ambience with K701 is spectacular - you feel like you're in the venue, when the recording allows. resolution, presence, resolution and more presence. highs are never piercing, but extremly detailed and extend upwards for what seems like forever. the widest and deepest soundstage i've ever heard.

 this amp times like my old Naim gears, but without the fatiguing highs, poor instrument separation, and truncated tonality. rhythms ebb and flow, allowing the music makes more "sense". the Bijou's impressive instrument separation helps quite a bit. 

 i'll post more impressions later. i'm one happy bunny.


----------



## UglyJoe

Hey guys, I'm really considering building this amp and I'd like some opinions before I jump in. I purchased a pair of HD650's about a month ago, and so far I'm really enjoying them. Currently I'm driving them with a Millet Max, with blackgates bypassed by VitQs and 2SA2344/2SA1011 BJT output transistors. I love the setup right now, but everything I've read seems to indicate that HD650's love all-tube amps, and a LOT of people who build the Bijou seem to be driving 650s (from a quick browse of the various Bijou threads). I was wondering if anyone has had a chance to compare the two amps with 650s and could give me an idea on the different sonics of the two setups, and if it is a "real" upgrade to go to an all-tube design like this that is still in the price class of the Max, or if it would be better to save money and go for a more expensive, all-out amp down the line like a balanced beta22, etc.

 Thanks for any suggestions.


----------



## amphead

While I do love the sound of my Millet Max, it isn't fair to compare the 2 amplifiers. The Bijou runs with the authority that higher power will bring. I have listened to the Bijou with K701 in SE mode and HD650 in balanced mode. But not with HD650 in SE mode. My interpretation is the they both sound fantastic, and the HD650's are darker or more prominent with lower mids. That said, the Bijou is an awesome amplifier, and if you decide to build it, welcome to the club. Now that you have successfully built the Millett Max, you are probably ready to carefully build the Bijou, paying close attention to High Voltage safety procedures.

 Pabbi, there is one thing that I noticed about your amplifier sockets that might cause intermittent static sound. They are phenolic, but more importantly they have a light grip of the pins, versus the ceramic sockets that I am used to, which have a firm grip on the tube pins. I don't know that I could recommend replacing all of the amp board sockets with ceramic, but if you did want to you could install the uber silver/gold contact variety. It would be a hell of an undertaking though, removing tube sockets is not for the faint of heart. ;-/


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, there is one thing that I noticed about your amplifier sockets that might cause intermittent static sound. They are phenolic, but more importantly they have a light grip of the pins, versus the ceramic sockets that I am used to, which have a firm grip on the tube pins. I don't know that I could recommend replacing all of the amp board sockets with ceramic, but if you did want to you could install the uber silver/gold contact variety. It would be a hell of an undertaking though, removing tube sockets is not for the faint of heart. ;-/_

 

Well, I am not going to replace the sockets - too much risk. In reality, it is only 2 of the sockets that are a bit loose, or rather, don't grip with authority. How about this - might I 'plump up' the pins a bit by tinning with solder? Since these are $4 tubes, that seems a path of lesser resistance - and, yes, would always have to be so - but at once every year or two, I can live with that.

 WRT Bijou vs MillettMax, I have dreaded this discussion. Caveats: I have no experience in SE with either configuration, and my Max has Cerrafine / Muse with VitQ. Oh, and the Millett has an OPUS DAC vs the Bijou using an Azur 840c (very unfair fight, but we'll continue on).

 Amphead has already laid out the technical differences in low V - high V, but it is a lot more than that. The Bijou rolls quite a number of tubes, where the Max has 3 basic flovors, where I am forever committed to the 12fk6 (found the 12ae6a way too bright). Also, I use all Russian tubes in the Bijou, 6n1p and 6n6p, so, again, my impressions are based on that alone. Finally, I usually prefer my hd600 to the hd650, and there is the matter of which cable, the Apuresound vs Enigma Oracle, the best two Senn aftermarket cables available, IMHO.

 Ok, the Bijou is simply superior on instrument seperation, soundstage, component (instruments, vocals, effects) placement. The Max smooths out some rough edges, but the Bijou presents exactly what is there in a 'stat way (Stax mafia alert).

 I don't want to say much more than that, as I want several second opinions, and direct comparisons against big guns, like the balanced Beta 22, RSA anything, Singlepower anything, and even against my Blue Hawaii / he60. THAT is where the comparison needs to be made, not against the Max.

 The Max is very nice getting into hybrids as a safe voltage, but, the real thing you need to look at also is the SOHA II. Senns love them both.

 But, Bijou also love the Senns, and Senns love it back.


----------



## digger945

I would love to know how the Bijou stax up (BONUS) against the Aikido also, especially in light of fierce freak's comparison of the aikido to his own beta22, and giving the nod to the aikido in more than one area.
 Wanna trade for awhile?
 Is a mini-meet in order?
 Since I own a millettHybrid, I won't give millett/aikido impressions, I just wanna listen.
 Ain't it all good anyway?
 I'm kinda partial to the 12FK6 also.


----------



## UglyJoe

pabbi and amphead, that seems like a pretty ringing endorsement for the Bojou vs. the Max. Kind of surprised really, because I really do like my Max a lot, although I haven't had the luxury of hearing a balanced beta22 or RSA B-52 or anything in that class. Like I said though, I've heard in multiple independent sources that the 650s really love that all-tube power.

 Anyone else with a take?


----------



## pabbi1

Do not mistake me - I have been listening to the Millett daily since my BH went on sabbatical (January, but now returned from the dead). The problem you will encounter is that very few folks have a Bijou, and Amphead and I are the only two I know of that happen to have built both.

 I also urge you to wait for other posts - we will be shooting these amps out at the Dallas meet against the top players (Beta 22, Zana Deaux, Singlepower, and more), so, sadly the people who can comment is very limited at the moment.

 More are likely to be able to comment about Max vs SOHA II - and sadly again, the higher voltage wins again, rather handily.

 Oh, Senns love tubes - I had Wheatfield HA-1 and HA-2 prior to this, and a first generation Millett - tubes are the answer for hd6x0.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_but the Bijou presents exactly what is there in a 'stat way (Stax mafia alert)._

 

what are you using for IC wiring from your source to Bijou, and also amp hook-up wiring? i'm looking to experiment. i've never heard the Azure, but from what i've read, the sonic signature/presentation is fairly similar to the BM DAC1? 

 i like the Oyaide PA-02 feeding my Krell/ATC speaker kit, and am using it currently with the Bijou. i have some extra lying around that i will replace my silver plated copper for hook-up wiring as well.


----------



## pabbi1

It is APS v3 copper cored silver, where the silver is in some rough proportion equal to the amount of copper, not just a thin silver plate, and some voodoo teflon over the top in multilayers. All very proprietary to APS, and he does not sell it standalone. It is my xlr i/c as well as my preferred Senn cable. 

 Alex at APS made them - that isn't a place where I have found DIY has served me very well.

 All my internal wiring is Navships SPC, and some 1kv 16878/5 (200c) milspec from Allied W&C. That is just what I have to use on the 'stat amps, so I always have that in abundance.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_It is APS v3 copper cored silver, where the silver is in some rough proportion equal to the amount of copper, not just a thin silver plate, and some voodoo teflon over the top in multilayers. All very proprietary to APS, and he does not sell it standalone. It is my xlr i/c as well as my preferred Senn cable. 

 Alex at APS made them - that isn't a place where I have found DIY has served me very well.

 All my internal wiring is Navships SPC, and some 1kv 16878/5 (200c) milspec from Allied W&C. That is just what I have to use on the 'stat amps, so I always have that in abundance._

 

yes, i too used Navship's wiring in the Bijou. excellent stuff to work with.


----------



## rhester

I have built both the MHMax (many versions of it and 2 minis also) and the Bijou. I love the presentation of the Max (all varieties), as it seems to round off the rough corners on inferior source material. The Bijou is in a differnet league, with more power and truer to the sound of the source. This all comes thru comaprison with same digital front end feeding both amps (Cambridge 640 cdp > ML 360s dac > amp and computer > Alien or BantamDAC > amp). I also have a Beta22 that is totally different from both, but that is a different discussion.

 I love all the amps and think they all have their special place, and they all haveb their own faults. It is a matter of what you like in sound: traditonal tubey sounds with rolled bottom and top ends; or more refined tubes with great detail and refinement; or solid state with tight, deep bass and airy top end. 

 Why not build all and change the amp with your mood.


----------



## UglyJoe

Quote:


  Originally Posted by *rhester* /img/forum/go_quote.gif 
_I have built both the MHMax (many versions of it and 2 minis also) and the Bijou. I love the presentation of the Max (all varieties), as it seems to round off the rough corners on inferior source material. The Bijou is in a differnet league, with more power and truer to the sound of the source. This all comes thru comaprison with same digital front end feeding both amps (Cambridge 640 cdp > ML 360s dac > amp and computer > Alien or BantamDAC > amp). I also have a Beta22 that is totally different from both, but that is a different discussion.

 I love all the amps and think they all have their special place, and they all haveb their own faults. It is a matter of what you like in sound: traditonal tubey sounds with rolled bottom and top ends; or more refined tubes with great detail and refinement; or solid state with tight, deep bass and airy top end. 

 Why not build all and change the amp with your mood._

 

cashe


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## pabbi1

Ok, she is holding up, with just an occasional bit of naughtiness (a second or two an hour) so I threw 'Joe's Garage' at her - stunning. Period. Telefunken U47 goodness all around, with texture, layers, and hidden gems everywhere, which is no surprise as this is one of the best produced albums ever. Oh, and Frank playing the Hendrix 'Monterrey' strat helps with the jena sais quois.

 This is am amp I could really fall in love with if I am not extremely careful.


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## amphead

That is great news.  I'm not sure what direction to pursue for the odd static that shows up intermittently. An oscilloscope can find it in the hands of an experienced tech/engineer. I think you are able to get 99% enjoyment, as it stands. So the 1% will come eventually, with a divide and conquer approach, breaking up potential problems into segments and checking them off. Edit: the amp is worth any parts upgrades that you can throw at it, so maybe you will go with goldpoints/w pcb in the future. Very easy to solder those in on the pcb vs soldering to the connections on the rotary area of the attenuator.


----------



## pabbi1

I am looking at TKD - the 41 position stepped 2P65S - my only real criticism of the Goldpoints is the 23 steps.

 But, it is still astounding how crappy some really well known works are (Radar Love, for instance), and how spectacular Dylan sounds on "Blood on the Tracks'... in the working my way through the collection (just 400 more discs to go - still 30 Zappas alone), this amp identifies the pretenders, and makes me appreciate a good producer all the more.

 I made two mistakes on this build - using the wrong sockets (next build is getting teflon with 3x grips) and cheap attenuators (never again on a quality build) - all Goldpoint or TKD from here on out.


----------



## runeight

You know, Pabbi1, it is not impossible to replace those sockets. You may not want to fool with it in taking the amp apart, redoing the boards, and then putting it back together, but . . .

 If you pulled just one board at a time, with a good solder sucker, it would be easy to get the solder out of the holes for the sockets. And just doing one board at a time would allow you to reinstall that board with its wiring without having to just disassemble the whole thing.

 OTOH, with your broad experiences building this amp, you may just want to start fresh and do many things differently.

 Just a thought for you . . .


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## pabbi1

I am really inclined to leave it the way it is, especially if it stays settled down, mainly because it is painful to pull 3 of the boards, as they are on a seperate plate, and everything has to come apart to get to any of them. And, my track record on rework is less than stellar.

 So, I take it the idea of fattening the pins with solder was not reasonable?

 The real issue is, as you may well remember, we are pursuing the stat amp (in prototype stage starting in about 2 weeks), so, if this holds up, I'll not have any time to 'fix' it until sometime in January or February. But, the annoyance is becoming less and less, so the cost benefit isn't there just yet.

 And, I have a functional Blue Hawaii sitting idle... how many people can say that?


----------



## runeight

OK. Makes sense.

 Regarding the pins, the risk to adding solder will be that you heat the pin so much that you break the vacuum seal with the glass. In fact, I think it's probable that this will happen. But you can always try this on a cheapo throw away tube to see what happens.


----------



## fishski13

the tube sockets i bought from Radio Daze are phenolic as well, but the pin holes are tight. i think i paid about $4 a socket.

 could you also try heating the pcb contacts with an iron and feed a tiny drop of solder into the pin socket itself? you could also do this from the top? might also need a toothpick to keep the hole open. maybe, i don't know.

 another possible approach to remove the sockets would be to use a small flush snipper from the top side of the boards and snip off all the pcb contacts you can reach. i would think that if you could snip at least half of them, de-soldering the rest would be much easier with less risk of pulling of a pad. either way, a huge PITA.


----------



## pabbi1

I'm also looking to see if I can brush on a thin layer of JBWeld to fatten the pins... desperate times...


----------



## amphead

Quote:


 another possible approach to remove the sockets would be to use a small flush snipper from the top side of the boards and snip off all the pcb contacts you can reach. 
 

You read my mind Fishski. Snip from the top side and solder sucker, with caution and determination. Well, as you say Pabbi the fix can come later after you have enjoyed it for awhile and have run out of material to listen to. You could do 1 board and listen for quite awhile before taking on another one. No pressure though, you are getting plenty of enjoyment.


----------



## runeight

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I am building a push pull el84 stereo amp, specifically going to do a version of the 'baby huey' design that is floating around. 

 most of the cost is the iron! tranformers are so expensive. 

 I'll look forward to your design, drop me a pm if you want prototypers when the time comes..._

 

So, Adamus, how's your new amp doing?


----------



## adamus

I am just at the ordering phase at the moment. Trying not to let costs get too much...... but just ordered $30 of obbligato caps. 

 I doubt i will get time to finish it before christmas, very busy at work at the moment. 

 should be fantastic when done though... fingers crossed.

 schematic here: http://www.diyaudio.com/forums/showt...626#post826626

 Initially i will remove negative feedback.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_You read my mind Fishski. Snip from the top side and solder sucker, with caution and determination. Well, as you say Pabbi the fix can come later after you have enjoyed it for awhile and have run out of material to listen to. You could do 1 board and listen for quite awhile before taking on another one. No pressure though, you are getting plenty of enjoyment._

 

The odd thing in all this is that it is only one one side, where I used the same sockets all around... so, I might tinker with the left side sockets a bit, but am all but certain I know which two sockets are the problem children. Jbweld on the pins will not work as it is epoxy, and non-conductive.

 I mean, how long could it really take to change out a couple of sockets?


----------



## chobint

if you can snip the pins as suggested it should be pretty easy. Heat the joint and pull the pin while it's hot. Suck up all the solder remaining and start over.


----------



## luvdunhill

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I mean, how long could it really take to change out a couple of sockets? 
	

	
	
		
		

		
		
	


	





_

 

Al, how experienced are you with bribing women? okay, don't answer that.. anyways, I wouldn't mind taking a look at it on Wednesday, but I'm not sure how long I can stay out 
	

	
	
		
		

		
		
	


	




 I have the best (cheap) tool ever for dealing with this stuff though. I purchased it from Consolidated Electronics, Incorporated. It's a combination solder sucker / iron thingy.. for around $25. Much better than the Rat Shack bulb version. Problem is, they don't sell replacement tips for it (but mine lasted 3 years or so), but disposable tools are okay in my book. I'd recommend picking one of these up, they are very easy to use and will improve your desoldering confidence 10 fold 
	

	
	
		
		

		
		
	


	




 Bad news is I have some strange ear thing going on now, so I won't really be able to enjoy the Bijou ...


----------



## pabbi1

Senior, you and I have many other matters to attend to, like a trip to Tanners, sorting a Mouser order, looking at a BOM, oh, and rebiasing the BH. But I was counting on you hearing the Bijou... if that is shot, I may as well tear her down to replace sockets - AFTER you concur somewhat that is the issue.

 You could bring some of those 9 pin pcb sockets (assuming you got them), as the teflon hasn't made it in from Taiwan.

 I will say I am usually better at making arrangements with the women I am not married to - if we have two in the mix (yours and mine), I think we are hosed.


----------



## luvdunhill

ok sounds good! At least you're not asking me to build another one of these


----------



## digger945

Run a piece of vacuum hose from your running car, through the window. Install a piece of telescoping antenna into the end. 

 Get busy! LOL.

 Have you considered just cutting the socket legs, one at a time?


----------



## JamesL

I would give ChipQuik a try. 
 It's made for SMD rework, but it's worked really well for me at removing multi-pinned through-holes.


----------



## amphead

Pabbi, did you order teflon or ceramic sockets?


----------



## pabbi1

I have teflon coming for the prototype electrostatic amp... and already have some ceramics hanging around. This is really more about hassle factor than anything else. Edit: Especially since it is perfect for hours on end, then a little crackling, only audible in between tracks. Even odder, when it is constant (like after leaving the amp on all night), it clears up pretty much with a simple power down and back on.

 Right on the border of flee or fight.


----------



## pabbi1

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_ok sounds good! At least you're not asking me to build another one of these 
	

	
	
		
		

		
		
	


	


_

 

That sure is pretty - but you know good and well I need TWO... the Caddocks are a nice touch. How about Rikens for mine? 
	

	
	
		
		

		
		
	


	




 Husky: The balanced Bijou makes Rush just that - absolute precision, and balance. Peart's drumming has never sounded snappier, the guitar lush, and Geddy's voice, well, listenable... not exactly like a dog caught in barbed wire.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Husky: The balanced Bijou makes Rush just that - absolute precision, and balance. Peart's drumming has never sounded snappier, the guitar lush, and Geddy's voice, well, listenable... not exactly like a dog caught in barbed wire. _

 

hey, thems fightin' woords. the Geddster's got a fine weedy rock voice 
	

	
	
		
		

		
		
	


	




.


----------



## fishski13

i actually used to be the biggest Rush fan when i was a teenager - i had all their albums on cassette up till the Presto Tour (i much prefer the older stuff). i was 14 and my mom picked me and a buddy up in Limo for the concert. if i remember correctly, the opening band's guitarist, Paul Gilbert of Mr. Big, used a power drill during a wank-out solo and caught his long hair locks in the drill bit. ha-ha...sorry, a bit off topic.


----------



## pinkfloyd4ever

YouTube - Chester Cheetah


 edit  Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_ if i remember correctly, the opening band's guitarist, Paul Gilbert of Mr. Big, used a power drill during a wank-out solo and caught his long hair locks in the drill bit. ha-ha...sorry, a bit off topic._

 

LMAO that's awesome!!


----------



## chobint

Quote:


  Originally Posted by *pinkfloyd4ever* /img/forum/go_quote.gif 
_YouTube - Chester Cheetah


 edit 
 LMAO that's awesome!!_

 

haha too funny. Awesome clip. Reminds me of the cookie monster with the spoon and the lighter bit.


----------



## pabbi1

Another flawless night without a single scratch / hiss / whatever - dead silent background. And, let us dispell this myth of rolled off bass - Geddy's Rickenbacker 4001 sounds _exactly_ like a Rick should, with every note precisely presented, and deep - you can hear what sets a GREAT bass player apart from the pedestrian - maybe I'll listen to a little Cris Squier and John Entwistle this evening.

 She seems settled in, or there is some other mischief afoot, so, for now, it is done, but I'll keep a couple of sockets on the desk in case.

 For the 6n1p and 6n6p crowd - any quality issues with either tubes, and, perhaps, do they just take a week or so to settle in?

 And, Senior fishski, what are your impressions thus far?


----------



## pabbi1

n/m - double.


----------



## chobint

Glad to hear you're back in business pabbi.

 So Alex, I too am looking into a tube speaker amp, would you perhaps have a rough ballpark figure of the power output and the price range you are shooting for?

 PS: pics tonight of something fanci I got from Australia (gogo USD exchange rate)


----------



## runeight

chobint, this would be a tube hybrid amp with the O/P power still provided by sand.

 I am shooting for 100W into 4R. I believe this is relatively easy to achieve for the first version of the amp.

 As for cost, I can't estimate that yet. I've already designed a board for one channel of the amp, but in a power amp like this most of the cost is in the PS, the heatsinks, the auxilliary circuitry, and the box. The only way for me to even rough this out will be to build one.

 I have another project, however, between here and there which is in the works now. I am a little hesitant about how quickly to proceed because, like many of you, I am wondering where the economy is going. Nevertheless, I have just ordered pieces for the enclosure for the project that is on the drawing board now.

 Wish I could be more specific, but I can't right at this moment.


----------



## ericj

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Another flawless night without a single scratch / hiss / whatever - dead silent background. And, let us dispell this myth of rolled off bass - Geddy's Rickenbacker 4001 sounds _exactly_ like a Rick should, with every note precisely presented, and deep - you can hear what sets a GREAT bass player apart from the pedestrian - maybe I'll listen to a little Cris Squier and John Entwistle this evening.

 She seems settled in, or there is some other mischief afoot, so, for now, it is done, but I'll keep a couple of sockets on the desk in case.

 For the 6n1p and 6n6p crowd - any quality issues with either tubes, and, perhaps, do they just take a week or so to settle in?

 And, Senior fishski, what are your impressions thus far?_

 

I think it really was close to 50 hours of solid use before my 6n1p-6n6p bijou settled in. 

 I gave an account of it's wanderings over on HW back in the day.


----------



## chobint

Just got these buggers in from Australia middle of this week. The combination of a favorable exchange rate and exemption from Australian taxes put these at 84$ each. That's less than half the best price I found from US vendors. What a steal! I hope to be donning these inside my amplifier by the end of the night, time and SPACE permitting 
	

	
	
		
		

		
			




 edit: thanks for the info runeight


----------



## pabbi1

Shall we call it 'The Ferrari Factor'? 
	

	
	
		
		

		
		
	


	




 Though, the PartsConnexion prices are very nice until Saturday - 20% off the Mundorfs and Jensens, if anyone is also leaning this way. I have some M-Tube caps inbound, but for another project.


----------



## chobint

haha ya, or "Ferrari Fever" perhaps. All who see his Bijou build get a sudden insatiable itch to buy large film caps. I had actually given up wanting these, but after stumbling upon them at that price I had to jump on it. Merry xmas to me 
	

	
	
		
		

		
		
	


	




 These things are friggin huge. I had to redo some wiring to fit them in. My dad says to me over the phone while unpacking them for me last week "What am I looking for here? It looks like a couple of soda cans." haha, good times. Looking forward to more listening over the long break.

 Hooray for cellphone pics


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_And, Senior fishski, what are your impressions thus far?_

 

i finally received my resistors to re-build my attenuators today, and another 4-pin XLR to balance my HD650. like i said before, i still only have 5 clicks worth of resistors soldered in, and my max SPL is around 75 dB for "hotter" mastered recordings - thus, classical and jazz have been MIA during my listening. i typically listen a bit louder, with peaks up to 85 dB. i've been a bit reluctant to post much re: sonics until i can get some more dBs. but i think i can safely make a couple of observations that will translate as well, or even better, at higher dBs with the K701 balanced.

 -the Bijou has a very beguiling way of carving out a "wave of sound" for a particular instrument/musician. it's hard to describe. it's as if each instument has a different way of pressurizing the air that hits you ear drum. i don't know if you would call this timbral accuracy or what, but instruments _feel_ more like this real thing rather than just _sounding_ like a facsimile. there's also the superbly detailed transients that help to create this as well. 

 -notes start and stop on a dime with zero muddling overhang. timing and the ability to unravel multiple musical lines while still retaining a "cut from the same cloth" presentation is equal to any Naim i've heard. musical.

 -massive soundstage in all directions, especially on the z-axis. on several recordings the K701 have disappeared and i felt like i was "there". i feel cheesy for saying saying that, but it's what i heard/felt.

 any comparisons between balanced and unbalanced would be pointless at this time as i have yet to wire for unbalanced with my new attenuators in place. before balancing my Bijou, i was using a crappy RS pot.

 i'm in the middle of a 72 hr work week and am leaving town for the weekend. i won't be able to get around to re-building my attenuators until Sun. night, but will definately be balancing my HD650 first thing when i get home in the a.m. 
	

	
	
		
		

		
		
	


	




.


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_haha ya, or "Ferrari Fever" perhaps. All who see his Bijou build get a sudden insatiable itch to buy large film caps. I had actually given up wanting these, but after stumbling upon them at that price I had to jump on it. Merry xmas to me 
	

	
	
		
		

		
		
	


	




 These things are friggin huge. I had to redo some wiring to fit them in. My dad says to me over the phone while unpacking them for me last week "What am I looking for here? It looks like a couple of soda cans." haha, good times. Looking forward to more listening over the long break.

 Hooray for cellphone pics


 




 

_

 

ooh la la...


----------



## amphead

Good stuff Chobint! Ferrari knows good caps! 

 Well Pabbi, let's just see how much your amp settles down.


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## fishski13

balanced Bijou + balanced HD650 = 
	

	
	
		
		

		
		
	


	




 it's nice to have some bass back in the sonic window.

 i'm in the front row, with some dBs to spare....nice.


----------



## huskydawg9

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Just got these buggers in from Australia middle of this week. The combination of a favorable exchange rate and exemption from Australian taxes put these at 84$ each. That's less than half the best price I found from US vendors. What a steal! I hope to be donning these inside my amplifier by the end of the night, time and SPACE permitting 
	

	
	
		
		

		
		
	


	



 edit: thanks for the info runeight





_

 


 where did you get those from exactly????


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## huskydawg9

Ok...this is cool. Just listened to the Doors Riders on the storm...and heard something I never heard before (or maybe just never this clearly). One of the other band members clearly whispering the lyrics. I betcha it sounds bad a.. with the balanced version.


----------



## huskydawg9

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i actually used to be the biggest Rush fan when i was a teenager - i had all their albums on cassette up till the Presto Tour (i much prefer the older stuff). i was 14 and my mom picked me and a buddy up in Limo for the concert. if i remember correctly, the opening band's guitarist, Paul Gilbert of Mr. Big, used a power drill during a wank-out solo and caught his long hair locks in the drill bit. ha-ha...sorry, a bit off topic.




_

 

I have to agree. Classic Rush is the best. I just bought remastered Rush (1st album) and a remastered Caress of Steel and the Bijou makes 'em really live. ...Wonder what it sounds like balanced... bet it's uncomparable.


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## fishski13

scored an on-call shift last night - the phone was silent. both 23 click attenuators are done - 100 resistors total in shunt configuration. my head hurts after 7 hrs of soldering. these bastards are huge 
	

	
	
		
		

		
			





. hope they sound decent 
	

	
	
		
		

		
		
	


	




. i have some pretty green KOA carbon 100K for the input resistors on each channel. 

 no time to wire these suckers up to the boards. past my bedtime.


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## runeight

fishski I've been meaning to ask you, what do you mean when you say "input resistors"?


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## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Well Pabbi, let's just see how much your amp settles down._

 

Nope, she spit the bit - it is those two sockets - touch the sockets, and get immediate scratchiness. It is definitely those left channel output tubes. Draining the boards now.

 I am finishing the casework, so, since it is coming apart anyway, I'll change those sockets to some nice ceramic gold, which I thought the phenolics would be better than - go figure.

 Won't finish until tomorrow as I need some hardware to finish mounting the faceplate and the xlr with it - but, getting closer - maybe Fishski and I are destined to be completely finished at the same time?


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## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_fishski I've been meaning to ask you, what do you mean when you say "input resistors"?_

 

sorry, "input" probably isn't technically accurate. here's a schematic for the ground shunt method i'm using. it's the R i/o resistor that defines the impedance of the attenuator.
diyAudio Forums

 and here's a spread-sheet of values for each step. 
http://www.diyaudio.com/forums/attac...amp=1178403288

 i've created my own attenuation curve with coarser steps over the first few positions and finer 1 dB steps after that. the Vishay RN60s are as large as deer pellets, and the attenuators turned out much larger than i was anticipating. i hope i don't have any noise issues.

 pabbi1,
 i won't be finished until next week. i'm heading out of town for a guys weekend away from the women-folk. i still need to re-do the faceplate and hook-up the boards. good luck with those sockets!


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## amphead

Fishski, have a well deserved respite from the build/troubleshooting.

 Pabbi, that was a great find, and risky as well. Sometimes we take a chance to get things done.


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## fishski13

i thought i would post some piccies of one of my attenuators before i leave town. i was hoping for the result to be a little "prettier", but i can't complain too much as this was my first attempt at building one. as the pics show, cleaning the flux residue off is a bit of a pain - will need to scrub more.

 enjoy the weekend!


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## amphead

Nice clean build Fishski. You take the recommended twisted pairs to the max. Very good and tight twists on the heater wiring. Attention to detail pays in the overall sound.


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## pabbi1

Done - almost.

 Changed the suspect sockets, and dumped the cheap atteuators for the TKD 2p2511 audio taper - dead quiet.

 But - (always a but) - the TKD are 100k total (50k per channel) and the cheap attenuators were 100k each channel. I was lackig a little output anyway (found it maxxed at 12 o'clock - strange), so I'll bump the NFB resistor from 125k to 160k - reasonable?

 With the 50k, I get about 9 o'clock on some things, less on others.

 Oh, and pron:


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## runeight

Pabbi1 do you want more gain or less gain? I guess I'm not sure.

 However, if you want more gain try 220k for the feedback resistor. If you want less, I don't recommend you go smaller than 125k in fixed feedback mode for high Z cans.


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## amphead

That's great news Pabbi! Looks good with the wood panel. Now a pic with top on.


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## pabbi1

I want less gain, and currently have 125k in the (fixed) NFB. Since the attenuators went from 100k per channel down to 50k, wouldn't I need to 'replace' that resistance in the NFB to keep the amount of total gain I had? It seems with the current 50k attenuators, I now have about double the gain from before changing the pots - which was the only change.

 We'll consider changing the overall gain after just getting back to where I was. This will be with Senn 6x0 only.

 As ever, could be exactly backwards - it is 50-50, and I can't always be backwards - well, maybe?


----------



## amphead

Are your TKD pots built with smd or regular resistors?
 Edit: scratch that idea, those are pots not attenuators. They have a wiper and a track.


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## pabbi1

It's this one  at the bottom of the page- some smd, some wiper resistance - nothing I can hack. Edit: NOT motor controlled.


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## amphead

At the moment, I can't think of what can be done to fix it. As Runeight said, you wouldn't want to go much lower than 125K with high Z phones.


----------



## pabbi1

Looks like I'm back to the Goldpoint solution - adding a resistor (~45.5k) in front of the imput, then tie another resistor from there to G, where the value is the difference between that resistor and my 48.8k pot value. Since I have some 3.3k on hand, I just have to find some 45.5k for the in lead.

 Always freaking something. Too bad I didn't think about this when I was getting resistors earlier at my surplus store, not that they have 45.5k, or some other similar combination of 48.8k.

 Just almost done...


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I want less gain, and currently have 125k in the (fixed) NFB. Since the attenuators went from 100k per channel down to 50k, wouldn't I need to 'replace' that resistance in the NFB to keep the amount of total gain I had? It seems with the current 50k attenuators, I now have about double the gain from before changing the pots - which was the only change.

 We'll consider changing the overall gain after just getting back to where I was. This will be with Senn 6x0 only.

 As ever, could be exactly backwards - it is 50-50, and I can't always be backwards - well, maybe? 
	

	
	
		
		

		
			



_

 

OK. I see what you mean. You have lost some amount of NFB, but not really that much. So drop the resistor value in small increments. Like 110k then 100k then 91k until you get what you need and the SQ is still good.


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## holland

I never really understood this. The pot value shouldn't affect the signal level that way...unless the tapers are different. 50k or 100k @ 50% attenuation should attenuate 50%.

 Yep, do the shunt mod. Actually I would do the other type.

Shunt Pot Volume Control - World-Designs-Forum

 You have one resistor in series and you use the attenuator to control the level to ground. Use 47k.

 If using the goldpoint method, try 25K for the input and 50k to ground. That should give you a 50% divider.


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## runeight

Well . . .

 In this case the way the NFB works is a little tricky. The NFB rheostat (or fixed resistor in this case) forms a voltage divider at the grid of the input triode. The bottom half of the voltage divider consists of the 10k grid stopper in series with whatever portion of the vol pot resistance exists between the wiper and ground.

 If the value of the pot is cut in half then the value of the wiper resistor to ground (for the same position of the pot if they are tapered the same) gets smaller. And because of this the amount of NFB goes down causing the gain to increase.

 I am surprised, however, that the gain has increased as much as it seems to have. So my suggestion that Pabbi1 reduce the NFB resistor in small increments.

 Regarding other techniques to reduce gain/volume just remember that any resistance that is placed in series with the output of the source reduces the HF bandwidth of the amp because it forms an LP filter with the Miller capacitance of the triode. Thus, keeping the series resistance as small as possible is generally the best way to go.


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## adamus

why not just go variable. PErsonally i find NFB has a big influence on sound.


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## TimmyMac

This thing is chewing through 6922's like nobody's business. One channel of my original JAN Philips one went really noisy, so I bought a pair of Electro-Harmonix. One of those went noisy, so I bought a pair of older 6N1P. Those were always pretty noisy. Is there a problem with my build?


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## chobint

Maybe we just need to get pabbi hooked on some k340's or a pair of sextetts. Those will just about halve the gain for ya 
	

	
	
		
		

		
		
	


	




 After a nice relaxing weekend of food, tinkering and extended listening, I found the effects of the new caps to be interesting. The most immediate thing I thought was wow the top end seems more detailed. I had my parents give it a listen too and one of them noted the treble seemed louder than before without me saying anything to them. I also noted a pretty big improvement in bass definition and quantity with my hd650's. I kind of expected this change, altho with the old -3dB point at ~8hz (70uF@300ohms), reasonably well out of audible range especially for headphones, I would not have expected such drastic improvement. I have dismissed most of my previous listening impressions as placebo since they were such minor changes, but after multiple days of listening the relative "imbalance" of the sound kept bothering me. That said, I am quite pleased with the new caps now that I'm used to the changes. I do, however, find the increase in upper detail interesting. Perhaps better caps = more info passed.

 TimmyMac, I've also found the number of noisy 6922/6dj8's in my collection disturbingly high. Of my 8ish tubes, I only have one white amperex 6dj8 that is perfectly quiet. I've had two staticy JJ 6922's, two staticy white amperex 6dj8's and one noisy green phillips 6922. All my voltages point to healthy amp operation, but repeated tube swapping proves that there's something wrong with my tubes. It makes me wonder...am I expecting too much? Do all tubes have just a tiny bit of static if you listen closely enough?


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## runeight

Some tubes have a persistent noise level that doesn't go away. But any well manufactured tube should get quiet after 50 hours or so of operation.

 It could be that you guys have some bad tubes. It could be the amp, but once the amp voltages are correct and if all the connections are solid, there is little that can go wrong in the circuit. The amp stage is very simple with hardly any components to it.

 So, it's probably the tubes. Probably.

 I have JJ 6922s in my Bijou and they are quiet and have been for a couple of years now.


----------



## amphead

TimmyMac, are your tubes tight in the tube sockets or do they move around? Also, is it a static sound, a buzz or a hum? And lastly did you do the ground mod? That will only help with a hum or a buzz.


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## pabbi1

Well, I replaced the 124k with 100k, and it is a little better, but I am still listening at 9-11 o'clock, depending on the disc, so it is useable. I'm not sure if it is real or imagined, but the TKD just are not as good as the stepped attenuators, even if the scratchiness is gone. For lack of a real technical answer, it sounds like the tops were sanded off the cymbals, the snare drum just does not have the same snap, and the bass is less clean. Oh, and the seperation is less seperate, or I am just not being very objective.

 My rational mind tells me a resistor is a resistor in the pot, but... just ain't the same. Big lesson: NO more cheap pots for me - Goldpoint or better for a deserving build. Oh, the eBay stepped attenuators are worth a crap shoot, but using the cheapies this time added two months to a build, and led to heartbreak in the end trying to justify keeping them.

 Second thought: The TKD are still way better than rk27, just, not way better enough to make me happy, or, as in this case, from believing the pots are (edit) NOT holding the amp back... at an added $180.


----------



## TimmyMac

Yeah, out of 6 6922/6N1P's I have only one that's even bearable to listen to - one of my original JAN philips ones which is extremely microphonic. Lightly brushing my finger on the top panel of the amp = loud sound in the channel that tube is in.

 The noisy tubes are static-y, not buzz or hum.


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## TimmyMac

I can move the tubes in the socket, but they're pretty tight.


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## amphead

Pabbi, did you lose detail with the TKDs or when you went from 125K to 100K?

 TimmyMac, I'm not sure what to make of the noise. You could pull one amp board at a time and reflow solder.


----------



## TimmyMac

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, did you lose detail with the TKDs or when you went from 125K to 100K?

 TimmyMac, I'm not sure what to make of the noise. You could pull one amp board at a time and reflow solder._

 

Noise follows tubes. I'm pretty sure it's just my tubes are going bad.


----------



## jamess71

Finally started the Bijou last night. Stuffed the PS board. Overlooked the Amphead mod. Should I do it now? Any reason not to? Also looking for suggestion for EZ81's


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## adamus

no, dont do it unless you have an unexplained hum. EZ81's, i have tried jj and brimar, and cant tell any sonic differences.


----------



## jamess71

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_no, dont do it unless you have an unexplained hum. EZ81's, i have tried jj and brimar, and cant tell any sonic differences._

 

OK I'll leave the PS board as is. Onto the amp boards tonight. Should I do the Regal mod right off the bat?? THanks

 James


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## adamus

tough one, some people have lots of overhead in the PS and get on fine, others find they cant get it to regulate at 250v. 

 IF i was starting again, i would probably regal mod, and use ecc99's (dont forget the different heater wiring scheme).


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, did you lose detail with the TKDs or when you went from 125K to 100K?_

 

Absolutely definitely with the TKD prior to changing any NFB resistors. It is still really, REALLY nice, but not what I know this amp is capable of. Enough to spend MORE $$$ looking for a better stepped attenuator, but only for the new 'stat amp. Maybe the Goldpoints are worth the $300, but, down the road somewhere.

 Again, I am letting a Blue Hawaii sit (temporarily) for the Bijou - with the stepped attenuators (and the days without the static), it was an even proposition. With the TKD, not so much. It also seems like the TKD make it slower, which might be why it sounds less crisp. Again, rationally this makes no sense to me, as smd resistance is smd, but wiper vs discrete should not be such a leap. <sigh>.

 So, the great attenuator hunt continues.


----------



## holland

For Regal's mods, why can't the 6N6P (or the 6N6P-i) be used?


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## chobint

I haven't heard any complaints of ill effects from amphead's mod. I would personally have done it right off the bat to cover all bases
  Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_tough one...
 IF i was starting again, i would probably regal mod, and use ecc99's (dont forget the different heater wiring scheme)._

 

x2. The worst thing that happens is your PS voltage comes up a bit short and you have to swap tubes or revert to default layout. Just be wary of disparities among tubes, my ec99's pull my PS below 250v, whereas my 6n6p's allow the PS to regulate 250v with ~10v of headroom, which is the opposite of what is typical.


----------



## adamus

holland, normally they are a bit thirsty, and will pull the ps out of regulation (more plate current).


----------



## Dantes

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_holland, normally they are a bit thirsty, and will pull the ps out of regulation (more plate current)._

 

Is there any probleme runing at 240V instead of 250V ? 
 My Bijou run fine with 240V and pairs of 6N6P-i and 6DJ8.


----------



## runeight

Dantes, the difference between 250V and 240V will be inaudible. However, at 240V you should make sure that C4 has at least 245V on it.


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_I haven't heard any complaints of ill effects from amphead's mod. I would personally have done it right off the bat to cover all bases


 x2. The worst thing that happens is your PS voltage comes up a bit short and you have to swap tubes or revert to default layout. Just be wary of disparities among tubes, my ec99's pull my PS below 250v, whereas my 6n6p's allow the PS to regulate 250v with ~10v of headroom, which is the opposite of what is typical._

 

hey, if you can spend money on those huge gucci cans, you surely can add a BJT PS multiplier mod 
	

	
	
		
		

		
			





.

 i bonked at the finish line. i just need to wire the input XLRs to the attenuators. a marathon session that included a re-do of the faceplate, and a stabbing of my index finger with some very sharp surgical scissors that continues to ooze. 

 hopefully all will power up fine tomorrow. this is one special amp.


----------



## Dantes

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Dantes, the difference between 250V and 240V will be inaudible. However, at 240V you should make sure that C4 has at least 245V on it._

 

There is little variations between 243 and 245V on C4.


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## runeight

Dantes, those voltages are marginal, but ok. Are you using the EZ81? If so, you might consider the BJT filter section posted a few pages back. Then one that fishski has verified that it works.


----------



## Dantes

Yes i use the EZ81 and i have done regal mod.
 I will done the mod as soon as i can.

 The sound is very good for now and dynamic 
	

	
	
		
		

		
		
	


	




 Thanks


----------



## chobint

Yaya, well now my PS is just barely regulating 250v /w ecc99 (hooray). I was waiting for my next project to order the parts for the PS mod. I almost pulled the trigger on the mighty midget for my grandparents, but my parents decided they are too deaf to appreciate the difference betweeen tubes and transistors haha. I think I may wait a year and see what alex cooks up. That, and I have something 30x more awesome in the oven atm 
	

	
	
		
		

		
		
	


	




 shh sekrat


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## fishski13

i mounted the attenuators and finished the I/O wiring yesterday. i still need to wire in a couple of blue super bright LEDs and buy some more chassis/faceplate screws.

 i think i nailed the attenuation curve i wanted/needed. been listening on and off for the last 24 hrs to a wide variety of music. background noise dead quiet on all 23 posistions.


----------



## amphead

Beautiful build and no noise! Thats what everyone aspires to produce. I like the logical layout.

  Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i mounted the attenuators and finished the I/O wiring yesterday. i still need to wire in a couple of blue super bright LEDs and buy some more chassis/faceplate screws.

 i think i nailed the attenuation curve i wanted/needed. been listening on and off for the last 24 hrs to a wide variety of music. background noise dead quiet on all 23 posistions._


----------



## pabbi1

Still learning about this amp, and I may have been a bit hasty. I was feeling a tad down about the sanded off snap of the percussion on harder rock, when I changed the attenuators. Keep in mind that most rock is highly compressed, and recorded in relatively small spaces.

 So, I changed the music.

 On goes the 'Concertos Brandenburgeois' (Archiv, W Germany) - and this amp creates a space the size of a full concert hall - just astounding if you have never heard the phenomenon. Not only does this amp create x,y spacing - it fills the ambient space with the reflective sound - almost holographic.

 Nothing I have ever heard has done this. Not pixie dust - just raw power to throw signals to where they need to be, when they need to be there - with open headphones.

 All amps have relative strengths - I just found this one on the balanced Bijou - anyone experience this on SE?

 And, RE: speakers: This recording has never sounded this spectacular, spatially nor dynamically in my 5.1 - truly, the headphones here kick the speakers to the curb.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Still learning about this amp, and I may have been a bit hasty. I was feeling a tad down about the sanded off snap of the percussion on harder rock, when I changed the attenuators. Keep in mind that most rock is highly compressed, and recorded in relatively small spaces.

 So, I changed the music.

 On goes the 'Concertos Brandenburgeois' (Archiv, W Germany) - and this amp creates a space the size of a full concert hall - just astounding if you have never heard the phenomenon. Not only does this amp create x,y spacing - it fills the ambient space with the reflective sound - almost holographic.

 Nothing I have ever heard has done this. Not pixie dust - just raw power to throw signals to where they need to be, when they need to be there - with open headphones.

 All amps have relative strengths - I just found this one on the balanced Bijou - anyone experience this on SE?

 And, RE: speakers: This recording has never sounded this spectacular, spatially nor dynamically in my 5.1 - truly, the headphones here kick the speakers to the curb._

 

pabbi1,
 i hear the exact same qualities. the sound is HUGE, x/y/z - slapping you from all directions. (warning: in-coming cliche) the differences between recording quality are there from album to album, but they all let the music through. musically, very satisfying.

 i've been doing a lot of switching back and forth between the K701 and HD650. more to come... 

 i didn't wire my Bijou for SE - i'm too lazy after spending 3 months on construction of the build SE, and then to balanced. i wish i could offer meaningful comparisons. pabbi1 and amphead, any thoughts???


----------



## chobint

looks great, clear front is a nice touch. I do love the DIY builds where you can see the insides.


----------



## fishski13

thanks guys.

 i'm going to crash out with the K701.


----------



## dBel84

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_All amps have relative strengths - I just found this one on the balanced Bijou - anyone experience this on SE?_

 

Happy to say that I hear this daily from my SE - another from Alex's stable. Now you need to put the dynamics away and get yourself some orthos and you're going to run 'screamin fo yo mumma' 
	

	
	
		
		

		
			





 . Very happy to hear that the Bijou has spread it's magic around..dB


----------



## adamus

fishski, if you dig out my review the one thing that struck me was the space the bijou creates. something i had never heard before. 

 With the 6n1p's in there i get space and a bit more aggression.


----------



## Dantes

I see a very bad default at that Bijou....
 .
 .
 .
 .
 It's too good. It spit at me all default of my source 
	

	
	
		
		

		
		
	


	



 I'll have to watch for a good DAC. 
	

	
	
		
		

		
		
	


	




 Very Nice Build Fishski


----------



## amphead

Quote:


 Nothing I have ever heard has done this. Not pixie dust - just raw power to throw signals to where they need to be, when they need to be there - with open headphones. 
 

Pabbi, you need to get that pixie dust back. Time to replace the TKDs with Goldpoints.  






 Seriously though, the spatial aspect of the balanced Bijou is just unbelievable. Reverberation from the walls, where the recording takes place is evident when it is present. The highs are crisp, but not overbearing, the mids are mellow as a french horn, and the bass is nice and deep, not flabby at all. Vocals are addictive and raise the hair on the back of your neck, acoustic guitar strings sound even better than live. So............gotta get my K701s wired for balanced and order the parts for the other 2 channels. I'll try to create a purdy chassis for the balanced setup.  Edit: Fishski, can I put you on the spot and ask how the K701s sound vs your other phones with the balanced Bijou?


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Pabbi, you need to get that pixie dust back. Time to replace the TKDs with Goldpoints.  





_

 

Well, *Goldpoint* tells me that there are some *48 step attenuators coming in the next few months* (with RC capability), so i am waiting just a bit.

  Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_Happy to say that I hear this daily from my SE - another from Alex's stable. Now you need to put the dynamics away and get yourself some orthos and you're going to run 'screamin fo yo mumma' . Very happy to hear that the Bijou has spread it's magic around..dB_

 

Well, Marc does have some T50 and is selling his ppa2, so no more SE for him? Regardless, you know where I am heading with the photomultipliers, and 1kv parts...


----------



## luvdunhill

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Well, Marc does have some T50 and is selling his ppa2, so no more SE for him?_

 

nope, still intrigued by something I heard in Houston, as well as some ultra high end ribbon tweeters == need moar cash.


----------



## pabbi1

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_nope, still intrigued by something I heard in Houston, as well as some ultra high end ribbon tweeters == need moar cash._

 

SOHA II, mayhaps?


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Seriously though, the spatial aspect of the balanced Bijou is just unbelievable. Reverberation from the walls, where the recording takes place is evident when it is present. The highs are crisp, but not overbearing, the mids are mellow as a french horn, and the bass is nice and deep, not flabby at all. Vocals are addictive and raise the hair on the back of your neck, acoustic guitar strings sound even better than live. So............gotta get my K701s wired for balanced and order the parts for the other 2 channels. I'll try to create a purdy chassis for the balanced setup.  Edit: Fishski, can I put you on the spot and ask how the K701s sound vs your other phones with the balanced Bijou?_

 

i'll post odd rambings here and there. 

 the K701 is actually a little more "groovy and fun" both SE and balanced, with a bit more dynamic punch in the midbass - but don't expect miracles in quantity. bass sounds like it goes down to DC 
	

	
	
		
		

		
		
	


	




. very detailed, but definately shelved down. percussion is amazing. very forward/enveloping soundstage - you're in the mix.

 i don't believe in the idea of "neutrality", but i think this is the sound that a lot of audio nerds would describe as "neutral" and analytical. i think the K601 would be an interesting pairing - definately a bit more groovy than the K701. the HD650 is another story...


----------



## amphead

Thanks Fishski, I expected there to be the usual analytical signature. And I am happy to hear that they are groovy and fun, overall. That's all the impetus I need to get moving on the balanced build. I will start with creating a chassis first, now that most of the mysteries of building the balanced Bijou are known by me. 
 Edit: there is an inexpensive way to hear the amp through a discreet resistor with very little dinero. You can measure the resistance of the volume pot at a favourite listening level and create a switched parallel circuit that switches in a single "boutique" resistor and switches out the pot. Not super practical, but it would work.


----------



## bhjazz

Coming from someone who only has parts for a SE verison, are there any comparison notes between the SE and the balanced? Soundwise, I suppose I have some expectations, but has anyone done a direct comparison?

 Thanks!

 EDIT: Just noticed some other inquiries about the same thing. Ah well, I'll stay tuned. We should organize a national Bijou-only Head-Fi meet...


----------



## fishski13

i'm learning more about how the attenuation curve i chose is working in situ with making volume adjustments. i took some dB measurements with my RS SPL meter and discovered that i was listening at a quieter volume than i normally do with the K701 - they require a few more clicks of gain vs. the HD650 to reach the same level of measured dBs. i was fooled by the more forward upper-midrange and trebles vs. the HD650. 

 i've now been listening at 75-80 dBs over the last couple of hours. the K701 are now on fire. very forward, Naim-like in presentation, but without the harshness in the upper-midrange, and a skosh more in tonality and warmth. gobs of transient attack and leading edge detail. bass is excellent as well. a bit of welcomed punchy warmth in the mid-bass a la Naim.


----------



## pabbi1

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Coming from someone who only has parts for a SE verison, are there any comparison notes between the SE and the balanced? Soundwise, I suppose I have some expectations, but has anyone done a direct comparison?

 Thanks!

 EDIT: Just noticed some other inquiries about the same thing. Ah well, I'll stay tuned. We should organize a national Bijou-only Head-Fi meet..._

 

Well, the only person I know that has had a balanced and SE at the same time didn't have a balanced source, so it is hard to say. I listened against a SE SOHAII, but only briefly, as it was promised to someone else. Wish I could help, but just don't have the data points. Somehow, I think the SE still has most of the same traits we are describing, where we are squeezing out a few last % points - well and differing order harmonics, even vs odd, IIRC.


----------



## fishski13

i've thrown everything at the K701 tonight - outstanding, and no NFB. Amphead, you're in for a real treat. 

 the HD650 (with stock cable balanced), as one could guess, has less emphasis on the leading edges of notes, and instead, trades this off for tone, tone, an more tone. a very colorful, meaty tonal palatte. definately not dull, quite the opposite, but rocks a chair on a different porch. more bass compared to the K701, and hits you in the gut like,







 without slop or overhang. an outstanding complement to the K701.


----------



## bhjazz

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Somehow, I think the SE still has most of the same traits we are describing, where we are squeezing out a few last % points - well and differing order harmonics, even vs odd, IIRC._

 

Cool. I should have suspected that the balanced version was a "last %" build, but thank you for the confirmation.


----------



## runeight

fishski, I just keep looking at the digitally manipulated photo. It is clever and bizarre and I don't know what all at the same time.


----------



## pabbi1

ESPECIALLY for us guys in Texas, and specifically in Dallas, who actually remember that day, and watching that on TV. At least the guitar is one in current production at the time, but a Strat would hav been far more killer than a Tele. It was a surreal time, for sure.

 Re the 'last %' - I just gots to have me that last % - the tone, and texture, with impeccable PRaT is just something I know is missing when it isn't there, and, it disappoints me greatly, like, say, using a MIM (or even MIJ) Fender, vs something pre-CBS, or, even '50s... it just freaking sounds better.

 The key word for now is texture, and multiple layers of it.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_The key word for now is texture, and multiple layers of it._

 

_textured_, spot on. vivid, colorful timbres, but never syrupy, soft, diffuse, or bloated. leading edges are crisp and articulate.

 i'm getting some new intermittent scratchy tube noise. i think my Sovtek 6n1p are re-badged NOS. hopefully it's just some old crud that needs to burn off.

 i've posted some pics over here:http://www.head-fi.org/forums/f6/pos.../index388.html

 i will be ordering a custom faceplate from FPE after the holidays.


----------



## pabbi1

I am still getting a little even after all the rework stomping - it is very faint, and only noticeable in the absence of signal. I am wondering if some 6nxp are better than others?

 But, when there is signal, it is not noticeable, and I just disappear into the music, even on things I don't like... the challenge really is understanding how things that have been available all along sound so layered / textured, but with the interpreted presentations from the past (bits sintered together), how the same song sounds entirely new.

 It is also crushing (and wonderful) to realize seemingly simple songs are so complex - and there really is a difference between a bar band and professional musicians.

 'Call of the West' by Wall of Voodoo, Zappa's 'Apostrophe', and Depeche Mode 'Violator' really hammered this home.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I am still getting a little even after all the rework stomping - it is very faint, and only noticeable in the absence of signal. I am wondering if some 6nxp are better than others?

 But, when there is signal, it is not noticeable, and I just disappear into the music, even on things I don't like... the challenge really is understanding how things that have been available all along sound so layered / textured, but with the interpreted presentations from the past (bits sintered together), how the same song sounds entirely new.

 It is also crushing (and wonderful) to realize seemingly simple songs are so complex - and there really is a difference between a bar band and professional musicians.

 'Call of the West' by Wall of Voodoo, Zappa's 'Apostrophe', and Depeche Mode 'Violator' really hammered this home._

 

yeah, i might end up sourcing some others if the noise doesn't disappear, but like you, it's very faint, intermittent, and never intrudes on the music.

 yes, the ability to unravel the seemingly tiniest dynamic details is amazing. you know when a guitarist's pick hits the string(s) and with how much force with relation to other notes/strings. you know when a bass player is out of synch with the drummer. music sounds more like real humans making music.

 i wonder how much this has to do with precise channel matching of the attenuators vs. balanced, or both.


----------



## fordgtlover

I bought 6 x 6n1p off ebay, and there are 2 of the batch that are really noisy. The two I am using at the moment are dead quiet.


----------



## pabbi1

I _think_ I am using 6n1p-ev, and everything I have seen available is from one of the former Soviet states... mine are all dampened as well, and probably at the 100 hour mark, burn wise.

 One other thing is how processed the vocalists are - and located in their isolation booth in the studio. It is wierd how producers bury a vocalist in the mix when they have thin pipes, just really different than a flat presentation where all the vocals and instruments are lined up flat spacially. Sometimes, I really feel like I'm sitting at the console, wanting to reach out for the sliders to change the mix. What I wouldn't give for a Steve Hoffman type to listen back to some of his mixes on this beast, just to tell me if this is real, or some other alternate reality.

 What is undeniable is the volume of air - whether it's pressure and placement is _correct_ is the current mystery. But, dayum, you sure appreciate a good PRODUCER with this thing - it really is unflinching, and, unforgiving.


----------



## amphead

I got to listen to one of my faves from times past on your rig Pabbi, before my Tascam CD players walwart died(will fix soon). Pali Gap from the Rainbow concert on the South Saturn Delta CD. It is one of the most melodic tunes that he played. It puts me into a mellow trance every time. Pali Gap is actually a windy mountain overlook in Hawaii. So some of us former residents of Hawaii, such as Amb and myself know it very well. The wind is strong enough to let you fly briefly. It lifts you off of the road for a split second, just like a wind tunnel. I am a lefty strat player, but unfortunately I play with the strings strung right handed. I was 50/50 on whether I would start building a guitar amp or the balanced Bijou and the Bijou came up "heads".  Edit: I start rounding up the aluminum for my custom balanced Bijou chassis on Monday. It gets the "eye candy" leds on the chassis panel.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I got to listen to one of my faves from times past on your rig Pabbi, before my Tascam CD players walwart died(will fix soon). Pali Gap from the Rainbow concert on the South Saturn Delta CD. It is one of the most melodic tunes that he played. It puts me into a mellow trance every time. Pali Gap is actually a windy mountain overlook in Hawaii. So some of us former residents of Hawaii, such as Amb and myself know it very well. The wind is strong enough to let you fly briefly. It lifts you off of the road for a split second, just like a wind tunnel. I am a lefty strat player, but unfortunately I play with the strings strung right handed. I was 50/50 on whether I would start building a guitar amp or the balanced Bijou and the Bijou came up "heads".  Edit: I start rounding up the aluminum for my custom balanced Bijou chassis on Monday. It gets the "eye candy" leds on the chassis panel._

 

great! i can't wait to see what "you're take" is on the Balanced Bijou. 
	

	
	
		
		

		
		
	


	




 i'm putzing around with some FPE designs right now. i enyoy playing around with their software.

 Alex's designs are wonderful - i want to build all of them. i also think that the CK2III i built for a friend is brilliant. it's my second favorite amp of all time, but only to the Bijou. i still would like to build a balanced SOHA II sometime in the next year.

 no tube noise this a.m.!


----------



## pabbi1

I have been through 3 of my 25 Hendrix discs, and Pali Gap has been a long favorite of mine as, and listened to it off that disc last week. Then dove into 'Axis: Bold as Love', where 'Castles Made of Sand' is my favorite... then to 'New Rays of the Rising Sun', which is rebranded 'Rainbow Bridge' (which originally had Pali Gap, curiously enough), where 'Driftin' and 'Hear my Train a Comin' are spectacular, along with 'Angel', 'Little Wing', on and on. 

 Funny you say that - my younger brother, a guitar player, on hearing the Bijou, asked me how to get that design into a guitar amp, as he has a friend here that builds those type amps. And I know Alex has mentioned vintage Fender more than once... 

 Now to spread the joy - how to get more Bijous into the hands of the masses?

 Oh, and Ron... can we revisit the line art version of the badge (and transfer that to Alex as part of his trademark, should commercial efforts come to fruition)?


----------



## amphead

Yes, that logo has been on my mind lately. Is it finished? I don't think it needs to be changed anymore. If so, someone could use the software from FPE to create a badge on a front panel. I think all rights to the logo should be transfered to Alex, in case a commercial build happens in the future.


----------



## pabbi1

Well, this is a jpg, but the laser guys want a line art version - sadly, I don't have any software to generate one. I like this one, but others may vote different.


----------



## amphead

Yeah, I can't say that I have used anything to produce line art. If someone does know how to do one in line art, then maybe they could give us some ideas. Maybe someone could make a pencil drawing from the original in Photoshop. My imaging software didn't have that option.


----------



## runeight

Gentlemen, if you will permit the designer to say just a few things. 
	

	
	
		
		

		
			





 Most of all, I want to thank all of you for the time and effort you have put into getting the best out of the Bijou. And for taking the time to listen to lots of music to really evaluate its SQ. I have, of course, been reading your comments (which are consistent with my sense of the amp) and have been grateful that the amp has been worth your effort.

 And, I really appreciate the offer of the emblem. I am happy to receive it. 
	

	
	
		
		

		
		
	


	




 I have thought about a commercial version of the Bijou, but I'd like to wait a little while as I am working on two other projects right at this moment.

 However, with regard to a commercial Bijou, there is, unfortunately, a British company that markets a headphone amp called the Bijou. I chose this name a long time ago, but they might have TM protection on use of the name. I haven't looked into this in detail, but it could be true. Would be great if it's not though.

 In any case, thanks again.


----------



## pabbi1

Yes, everything in it's time.

 We are truly the beneficiaries of the amp. Mine sounds better each day.


----------



## fishski13

would this free conversion program work: VextraSoft. Raster to Vector Conversion Software. Vectorize Your Images and Photo. ?

 i downloaded it, and converted the jpeg drawing to a vector drawing with the "Wizard" function, but i have no idea what i'm doing. does the image need to be printed, or can you save it as a file and send it to FPE. i know zero about 'puters.

 would .pdf files work? there are some free .jpeg to .pdf coversion programs.


----------



## pabbi1

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_would this free conversion program work: VextraSoft. Raster to Vector Conversion Software. Vectorize Your Images and Photo. ?

 i downloaded it, and converted the jpeg drawing to a vector drawing with the "Wizard" function, but i have no idea what i'm doing. does the image need to be printed, or can you save it as a file and send it to FPE. i know zero about 'puters.

 would .pdf files work? there are some free .jpeg to .pdf coversion programs._

 

That looks cool, and I'll try it tonight. The laser engravers say anything will work, but non-vector files will be diffused / fuzzy, so I want to make this as good as possible. They work with the actual file, so print reproduction is not part of the process. Line art will apparently make the x,y graphing a lot crisper.

 The plan is to do some on different material - I have a range of exotic woods (and may obtain some more - but the bocote, rosewood, koa, pecan) may look ok... along with some 6061 aluminum. Now, to figure out what size.


----------



## runeight

As far as FPE goes, the only way to import graphics is by using HPGL. This is graphics language created by HP. I don't know why they chose this one.

 So the image needs to be translated to HPGL. I think the dBel84 knows how to do this.


----------



## ericj

HPGL is more a printer control format. Probably the native input of the machine they use.


----------



## dBel84

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_As far as FPE goes, the only way to import graphics is by using HPGL. This is graphics language created by HP. I don't know why they chose this one.

 So the image needs to be translated to HPGL. I think the dBel84 knows how to do this._

 

yes the dBel84 knows how to do this 
	

	
	
		
		

		
		
	


	




 send me a decent res image and I will either convert it or redo it into HPGL

 ..dB


----------



## chobint

to nitpick...the gem is slightly skewed to the right in reference to the black base in the linked image. I donno if anybody cares or not, but I just thought I'd point that out before we immortalize the image by laserbeaming it into someone's amp.

 edit: and in the interest of not adding any more off topic jumble to this thread, I add these comments in an Edit. It's funny that you guys mention the Pali Gap and the word "flying." My family is from Hawaii and the wind is INSANE up there. Enough to pick me up off the ground as a small child many years ago. I have yet to hear the hendrix song tho. But there are many things I have yet to experience. /bows to the elders, haha


----------



## amphead

I will create a higher resolution image, with the correction of the skewed base, and post a link to it on this thread. Probably late this evening. Then dB can work his magic.


----------



## fishski13

excellent team work gentlemen.

 i think my 6n1p are now "clean". 

 the HD650 are heavenly with orchestral,reggae, and electronica. i'm prefering the K701 with smaller chamber works and ECM label stuff. the K701 do need to be cranked-up a skosh (closer to 80 dB) before they come on song though, but never fatiguing.


----------



## huskydawg9

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_excellent team work gentlemen.

 i think my 6n1p are now "clean". 

 the HD650 are heavenly with orchestral,reggae, and electronica. i'm prefering the K701 with smaller chamber works and ECM label stuff. the K701 do need to be cranked-up a skosh (closer to 80 dB) before they come on song though, but never fatiguing._

 

If you like the 6n1p's...you gotta try 6H30's. I haven't heard the NOS originals that Ferrari has...but the new stock available is reasonable and is a step up. 

 I have been using Grado 325i's. Most here use Senns. I'm very pleased with the sound of the Grado's. So much so that I am considering a balanced Bijou with Grado GS1000's (ok...it's a dream). What, if any...changes should I consider for the lower impedance?

 Lastly... I have both a Buffalo and a 24 chip DDDAC DAC's as sources. The Buffalo was purchased as a precurser to the balanced Bijou. But...since I added Russian teflons to the output of the DDDAC, the Buff is not even close. Makes me wonder what a balanced DDDAC and the balanced Bijou would do. I'm telling you...remastered classic Rush is absolutely phenominal (especially Xanadu) with my 24 chip dddac, SE bijou (with 6H30's and Regal's mod (very important!)) and Grado 325i's.


----------



## amphead

I'll try to get the new image tonight instead.


----------



## pabbi1

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_If you like the 6n1p's...you gotta try 6H30's. I haven't heard the NOS originals that Ferrari has...but the new stock available is reasonable and is a step up. ._

 

I looked hard at this, but REALLY, REALLY do not want to change the resistors to do so - is there some middle where 6n1p and 6H30 can coexist?

  Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_Lastly... I have both a Buffalo and a 24 chip DDDAC DAC's as sources. The Buffalo was purchased as a precurser to the balanced Bijou. But...since I added Russian teflons to the output of the DDDAC, the Buff is not even close. Makes me wonder what a balanced DDDAC and the balanced Bijou would do. I'm telling you...remastered classic Rush is absolutely phenominal (especially Xanadu) with my 24 chip dddac, SE bijou (with 6H30's and Regal's mod (very important!)) and Grado 325i's._

 


 Ok, dangit, I did buy '2112' Sunday JUST for 'Passage to Bangkok', but the whole thing, including the stinking 21 minute overture (that you cannot skip through) sounded amazing. Still can't quite squirm my way through 'Strangiata' (I know it isn't here, just sayin)... and, Neil Young's Martin D-45 on 'Double Live Rust' is spectacular. The Bijou is not the most all-around performer, but just stunning when she hits a song she likes.... tears in the eyes stunning.


----------



## huskydawg9

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I looked hard at this, but REALLY, REALLY do not want to change the resistors to do so - is there some middle where 6n1p and 6H30 can coexist?




 Ok, dangit, I did buy '2112' Sunday JUST for 'Passage to Bangkok', but the whole thing, including the stinking 21 minute overture (that you cannot skip through) sounded amazing. Still can't quite squirm my way through 'Strangiata' (I know it isn't here, just sayin)... and, Neil Young's Martin D-45 on 'Double Live Rust' is spectacular. The Bijou is not the most all-around performer, but just stunning when she hits a song she likes.... tears in the eyes stunning._

 


 You either love Rush, or you hate 'em. Of course you know which camp I am in.

 And of course to elaborate...I am now listening to "La Villa Strangiato" at MAX (pegged) volume, absolutely clear... very close to a religious experience with a SE version. Makes me crave your amp!

 I'm willing to travel to compare... (I'm in SW Michigan). I'd love to show off the DDDAC. I really believe it's the best match for the Bijou.

 BTW... as far as classic Rush goes...you've got to hear the remastered "a farewell to kings". There is a little noise in the background...but ...absolutely kicks butt. Check out Cygnus X1 after several beers at maximum volume. You won't be disappointed.


----------



## funch

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_If you like the 6n1p's...you gotta try 6H30's. I haven't heard the NOS originals that Ferrari has...but the new stock available is reasonable and is a step up. 

 SE bijou (with 6H30's and Regal's mod (very important!)) and Grado 325i's._

 

I couldn't agree more. I'm also running 6H30's with Regal's mod's, ECC99's, into HD600's. Actually, I 'stole' the 6H30 idea from you (thanks). Alex 
 should list a huskydawg9 6H30 mod on his site.


----------



## huskydawg9

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_I couldn't agree more. I'm also running 6H30's with Regal's mod's, ECC99's, into HD600's. Actually, I 'stole' the 6H30 idea from you (thanks). Alex 
 should list a huskydawg9 6H30 mod on his site. 
	

	
	
		
		

		
		
	


	


_

 

Actually, it's not really a mod. Just Alex's guidance on how to roll different tubes. The key is to install sockets so you can easily change R2 values.

 I like the ability to go back and forth and easily try different combinations. Initially I thought the 6N1p's were very comparable to the 6H30's. But Regal's mod changed all that for me. It REALLY made the 6H30's blossom. GO FOR IT. Even with the new stock...it's worth it.

 I'd love to compare the NOS dream 6H30 tubes with the Sovtek new stock side by side... as the Sovtek's are VERY sweet as is...

 Rush and Geddy Lee are punctuating this statement at MAXIMUM VOLUME, perfect clarity, as I write this...


----------



## bhjazz

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_Alex's designs are wonderful - i want to build all of them. i also think that the CK2III i built for a friend is brilliant. it's my second favorite amp of all time, but only to the Bijou._

 

Just spotted this. 

 I finished a CK2III earlier this year and it continues to be my favorite amp. We had it at a meet and it performed perfectly well with Sennheiser AND Grado. What a surprise. We couldn't believe it. There were some naysayers...until they tried the two brands back to back! 

 Yes, another vote for Alex here. Thanks for the musical gifts!


----------



## fishski13

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_If you like the 6n1p's...you gotta try 6H30's. I haven't heard the NOS originals that Ferrari has...but the new stock available is reasonable and is a step up. 

 I have been using Grado 325i's. Most here use Senns. I'm very pleased with the sound of the Grado's. So much so that I am considering a balanced Bijou with Grado GS1000's (ok...it's a dream). What, if any...changes should I consider for the lower impedance?

 Lastly... I have both a Buffalo and a 24 chip DDDAC DAC's as sources. The Buffalo was purchased as a precurser to the balanced Bijou. But...since I added Russian teflons to the output of the DDDAC, the Buff is not even close. Makes me wonder what a balanced DDDAC and the balanced Bijou would do. I'm telling you...remastered classic Rush is absolutely phenominal (especially Xanadu) with my 24 chip dddac, SE bijou (with 6H30's and Regal's mod (very important!)) and Grado 325i's._

 

if i understand correctly, the cap multiplier mod i added to my PSs, and the tweaked higher idle current (5mA) with Regal's Mod, i should have enough current to feed the 6H30 and splitter stages? would it be beneficial to have a higher idle current for the 6H30? R2 is socketed as well.

 as far as tweaking for lower headphone impedance, the amount of current available is limited to what the O/P tubes can deliver:
http://www.head-fi.org/forums/5027221-post1895.html


----------



## amphead

I have to put the logo on the back burner for a little while. I bought the aluminum for my balanced Bijou chassis, and have started that build. I figured out how to get a decent brushed aluminum look on the front panel which is 1/4 inch plate aluminum. I get my aluminum from a scrap metal business that sells it by the pound. First I cleaned it with dish soap, then I started sanding in strokes that only go in the lengthwise direction with, 320, 600, and then 1200 silicon carbide paper. While doing the last hour of sanding I used a guide on the edge of the panel to make sure the sanding was laser straight. It now looks like the stuff you see on the fancy elevators. Once I get far enough along, I'll post some pics. Edit: dimensions are 18 & 1/16 inches long by 14 & 1/2 inches wide and 3 & 1/2 inches tall. Just by chance it is exactly down to the millimeter as long as the NABU case, but 4 & 1/2 wider than the NABU and 1/2 inch shorter. That 4 & 1/2 inches is crucial to allowing enough of a footprint.


----------



## fishski13

i re-wired my Bijou this morning with only one 2 deck attenuator for balanced (see pabbi1's attenuator thread). sounds great, less work, and 1/2 the $$$.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I have to put the logo on the back burner for a little while. I bought the aluminum for my balanced Bijou chassis, and have started that build. I figured out how to get a decent brushed aluminum look on the front panel which is 1/4 inch plate aluminum. I get my aluminum from a scrap metal business that sells it by the pound. First I cleaned it with dish soap, then I started sanding in strokes that only go in the lengthwise direction with, 320, 600, and then 1200 silicon carbide paper. While doing the last hour of sanding I used a guide on the edge of the panel to make sure the sanding was laser straight. It now looks like the stuff you see on the fancy elevators. Once I get far enough along, I'll post some pics. Edit: dimensions are 18 & 1/16 inches long by 14 & 1/2 inches wide and 3 & 1/2 inches tall. Just by chance it is exactly down to the millimeter as long as the NABU case, but 4 & 1/2 wider than the NABU and 1/2 inch shorter. That 4 & 1/2 inches is crucial to allowing enough of a footprint._

 

i think building your own enclosure opens up a lot of layout possibilties. i assume that your tubes will be exposed through the top? i'm excited to see what you come up with.


----------



## jamess71

I'm a little bit confused on the R2 values using the Regal Mod. The input stage with 6922's shows R2 @ 487R. What values should be used with 6N1P and 6H30? I did put sockets in so I'm ready to roll.  as soon as I finish it that is.


----------



## runeight

They are:

 6H30 - 1k3
 6N1P - 180

 Note that the cathode bias on the 6n1p will only be about 900mV.


----------



## fishski13

i took out the Oyaide wire that i was using for signal hook-up wiring. i replaced it with the SPC from Navships that i had in before, but left the Kiwame 100K I/O resistor on my shunt attenuator soldered in. i lost some transients and imaging with the "thicker" sounding Oyaide - now it's all back with the SPC back in. i also prefer the the Kiwame over the Vishay at the I/O resistor with the K701. the HD650 can also play blugrass now. i just finished this phenominal album:






 more cable and resistor tweaks/experiments to come...


----------



## pabbi1

I just dropped in Beck's 'Sea Change' - and just, for lack of a better term, (figuratively) crawled up into the amp. The snap and speed are back with the TKD burnin - I will be quite interested in shooting this out against the SOHA II when it comes back in for a cleaning in a few weeks after two months in the desert.

 Or, maybe Marc will have his uber SOHA Deuce built by the January DFW meet.

 This amp (speaking Bijou generally, not mine specifically) deserves more fans than it has currently.

 Did I mention this amp loves guitars?


----------



## amphead

Yeah, I have heard a lot of great amps this year, having heard Orpheus phones paired with many different amps. The balanced Bijou gives some outstanding sound at a price point that makes it particularly attractive. When it is built properly with a quiet background and with good caps, tubes it really sings. It can be built quiet, with strictly parallel wiring of the heaters and tightly twisted wire with the ground mod.


----------



## adamus

I must have been lucky with my build, I cant detect any noise what so ever - even at max volume. I dont have the ground mod.


----------



## regal

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_
 I like the ability to go back and forth and easily try different combinations. Initially I thought the 6N1p's were very comparable to the 6H30's. But Regal's mod changed all that for me. It REALLY made the 6H30's blossom. GO FOR IT. Even with the new stock...it's worth it.

 ..._

 


 To use the 6H30's I am assuming you are using a separate filament transformer, because the 6H30's are using at least an amp more current, or is the standard transformer good enough ?


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_I just dropped in Beck's 'Sea Change' - and just, for lack of a better term, (figuratively) crawled up into the amp. The snap and speed are back with the TKD burnin - I will be quite interested in shooting this out against the SOHA II when it comes back in for a cleaning in a few weeks after two months in the desert.

 Or, maybe Marc will have his uber SOHA Deuce built by the January DFW meet.

 This amp (speaking Bijou generally, not mine specifically) deserves more fans than it has currently.

 Did I mention this amp loves guitars?_

 

Gents, I hope you will permit me to offer a few thoughts on Pabbi1's sentence about the Bijou deserving more fans (I appreciate the thoughts Pabbi1).

 But first, let me say that I never have a problem with people comparing amplifiers. I think anyone should feel comfortable comparing any amp to any other amp just to hear the differences. You may compare a $50 amp to a $1000 amp just to hear how the more expensive amp is better. Or you may compare two amps of similar price and technology to find out that the less expensive one is actually better. Or you may compare a hybrid amp to an all SS amp to see if you can hear differences. Etc. After all, what this hobby is about is the listening experience. 
	

	
	
		
		

		
		
	


	




 That said, I think that one thing that is happening to the Bijou is that it may be being put into the wrong class. That is, I have seen it compared often to the b22 amp from AMB, sometimes with a question as to which is the more satisfying/better build. Naturally, the Bijou can't really stand in this comparison because:

 1. The b22 is a brilliant high performance SS amplifier. Quickly counting the active devices in one channel, including the jfets in the CRDS, says that there are about 34 active devices in this amp. All of these devices are bent towards achieving the high performance of that amp. When you factor in the s22 supply, there are many more active devices. But, because sand is so cheap, the amp is very reasonably priced. I don't have a b22, but I rather expect that it is quite something to listen to, particularly in balanced mode.

 2. The Bijou, OTOH, is designed to be an entry level HV tube amp - something that an individual who has been wanting to try his hand at tubes could build with excellent results at modest cost. If you count the number of active devices in one channel of the Bijou it is exactly 4 (four triode sections). There is no sand, not even a CCS, in an effort to maintain a kind of tube purity in the amp channels. The PS has two fets in it, yes, but that's the only sand.

 Now despite this difference, the Bijou is still very good at what it does and can, at times, be brilliant itself. I do recall one individual saying that after making the regal mod he retired his DV337. This is, perphaps, a better comparison for the amp.

 Now, I am NOT complaining, as per my strong feelings above about comparisons. Only suggesting that the Bijou's reach may be being limited in part by what it's currently being compared to. OTOH, I have not seen, by any means, all of the comments here and in other places about the amp, so I may be totally wrong about this and will be very happy to hear comments from others that indicate that this may not be so.

 Furthermore, I am, as always, very grateful for the folks on this thread who have built the amp and who continue to listen to it.


----------



## pabbi1

If I may,

 I have heard two b22, one balanced, and will state, unequivocably, that the balanced Bijou gives the b22 a run for it's money in detail, intended or not, but it is superior in mid band tonal reproduction, especially on voice and strings. The Bijou's sound staging absolutely whips the b22 without any question.

 We will put this all to the test in January, as the balanced b22, balanced Bijou, and Pete Millet's 307a (SE) will be in attendance (along with some others, like maybe a Zana Deux, and some Singlepowers) in Dallas, with some really seasoned listeners / MOTs, where I think this all ultimately comes down to personal taste, and what the user wants to hear. 

 It would also be an honor to have the designer come hear it for himself, as well as the other offerings - the chance to chinwag with Pete is worth the price of admission. 

 Tempering expectations is one thing, but the Bijou can be built to perform within a few % of the top amps available in the market, and Super Bijou may well place it at even par.

 Do not shrink the design accomplishment. It speaks for itself, and can be mentioned in the conversation with any amp. No question it can stand against any other all tube amp, at least from what I have heard. And, after owning 20 amps or so, my experience is that all amps have strengths and weakness - finding the right tradeoff is the goal of the quest, and, no one amp can do everything (hence why I have 3, and am building a fourth).

 SS may be technical, but tubes are magic - and we can all use a bit of magic these days.

 Who says there ain't no Santa Claus? 
	

	
	
		
		

		
			





 PS: I have built a few of Ti's designs, and he IS a truly talented designer - this is in NO WAY reflective of the relative designers - and, in fact, wish 'the designers' collaborated a bit more than they do now. Competition is a driving force, but sharing ideas is a far more powerful tool.


----------



## regal

pabbi, just wait till you hear the Stacker 2. Mine died but the brief time I had it going it was like taking the best parts of the B22 and the Bijou in combination.


----------



## chobint

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_...I think that one thing that is happening to the Bijou is that it may be being put into the wrong class. That is, I have seen it compared often to the b22 amp from AMB, sometimes with a question as to which is the more satisfying/better build.

 2. The Bijou, OTOH, is designed to be an entry level HV tube amp - something that an individual who has been wanting to try his hand at tubes could build with excellent results at modest cost..._

 

I think you hit it right on the head. I think the Bijou and B22 are at the top of their class respectively. That is they are the "best", or at least most popular, of the well supported and kit-available pure-tube (minus regs) and SS projects. While it may be unfair to compare the two, such a comparison is implicit in trying to get the best out of your DIY experience. I asked myself the same question before starting..."bijou vs b22" and decided I wanted to see what all that toob magic was about

 edit: ya the stacker II does look sexy


----------



## pabbi1

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_pabbi, just wait till you hear the Stacker 2. Mine died but the brief time I had it going it was like taking the best parts of the B22 and the Bijou in combination._

 

Somebody wake me up.

 Seriously, we have been asking for updates on the Stacker II thread for 3 months... maybe someone can comment there? And, within the context of a balanced build.

 Oh, and I'd also like to raise the question of Super Bijou - if it is not for open forum, someone please PM me, even though I have other (electrostatic) fish to fry for the next 60 days, or so.


----------



## runeight

Right . . .

 Both amps are in progress right now. Both are undergoing revisions for various problems in the proto builds. Which is one reason that regal's died. The Super Bijou needed part of its PS completely redesigned.

 Progress on both has been a bit slow due to several factors in the proto groups that are not related to diy, but are just life issues that some folks have been contending with for a while.

 Neither amp is ready for open forum at the moment. But, maybe in a couple of months. By then I may have an interesting build to show too.


----------



## holland

Super Bijou????

 Man, I'm falling behind on projects, better kick my butt in gear...I'll never be able to catch up at this rate.

 Next year should prove to be interesting, with a couple of high end designs coming out (from what it appears is stated by runeight).


----------



## amphead

Yes, there is some Voodoo going on that has yet to be discovered. There are some builds that don't require the ground mod, however I think I'm seeing that nearly 50% of the builds are in need of the ground mod to get the background black. The performance doesn't seem to suffer doing it, so I recommend that new builders do it if they want to eliminate the possibility of a hassle. It is very inexpensive to do because of just the 2 resistors being required. Any wiring scheme other than strictly parallel wiring of the heaters doesn't work with it. No series-parallel, no daisy chaining etc. I'm guessing that's because of symmetry needed for the phase/noise cancelling of each twisted wire, with the "zero" point being where the resistors are tied to star ground, but that statement is more Voodoo, unless an engineer can verify that logic.

  Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I must have been lucky with my build, I cant detect any noise what so ever - even at max volume. I dont have the ground mod._


----------



## adamus

you mode is creating a CT, its common practice to do this on power valve amps, same principles apply. A lot fo people will use a hum pot - which was more applicable when resistors werent so precise.


----------



## holland

what's the purpose of the heater biasing scheme? haven't built mine yet, still working on component layout.


----------



## amphead

Holland, that is a technique listed on Alex's website. It is for the purpose of eliminating noise, when it becomes necessary.


----------



## adamus

Holland. 

 there is a potential difference between heater and cathode, this scheme biases the heaters to 40v, look at the schematic, there is a voltage divider with B+, but its not a close circuit so no current flows from the B+, it just superimposes 40v dc on the 6.3v wave.

 Often not needed, but in this schematic, the upper triode section's cathode is elevated to (if i remember correctly..) 100v ish. 

 This reduces the pd and prevents hum, and if you look at the tube datasheets, a max heater cathode voltage rating is prescribed, this helps keep that in check.


----------



## runeight

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_what's the purpose of the heater biasing scheme? haven't built mine yet, still working on component layout._

 

Adamus is right on this feature. The HK voltages for the tubes have maximum values. For example, the 6922's cathode can be a maximum of 135V positive with respect to the heater. The ECC99, IIRC, is about 200V.

 The cathode of the phase splitter is at 100V. The cathode of the top ECC99 triode is 125V. Both of these are within spec but I thought it was a bit safer to relieve some of this voltage difference, especially on the 6922 which is only 35V from its max. So I DC biased the heater supply to +40V reducing the 6922's HK voltage down to 60V. It is not absolutely necessary to do this, which is why amphead's mod works ok. It was an engineering choice to try to minimize any potential problems.


----------



## adamus

i dont think i posted photos with the final touches....

 again, thanks to alex.


----------



## whitelabrat

Wow, it's taken me a couple days to read this thread!

 I'm prepping to build a Bijou, but I'm stumped on some of the parts from the BOM. For example, the heat sink. I'll likely source most of the parts from Mouser. Help?

 I've already got an Allied 6K65VG power transformer that is 540vct at 120ma. I've also got a pair of 100uF Solen's and a pair of gigantic ASC 600uF caps that may be used on the outputs. Whatever doesn't get used on the HA2 clone I'm building too.

 I'm planning to use 6N1P-VI and 6N6Pi tubes cause I've got them. I've ordered EZ80's but it seems that EZ81's are the preferred option. I've also got 6bq7a's that would be nice, but are terribly microphonic, and have a weird hf ringing to them.

 I'll be using Enymotic Research er4s (100ohm) and AKG 240M (600ohm) headphones so far.


----------



## Ferrari

whitelabrat, TO-220 heatsinks from at least 1.5" high, available at Mouser under part number 532-513102B25 (for example) should be fine.


----------



## amphead

Whitelabrat, welcome to the Bijou build thread! Looking forward to pics of your progress.


----------



## whitelabrat

Thanks Ferrari. I just noticed the text section of the parts lists that has more detail about parts selection. Whoops!

 I have a tendency to put all my effort into parts, and then run out of money for a good chassis. I'm looking at an old PA that could be a doner.


----------



## pabbi1

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_I'm prepping to build a Bijou, but I'm stumped on some of the parts from the BOM. For example, the heat sink. I'll likely source most of the parts from Mouser. Help?

 I've already got an Allied 6K65VG power transformer that is 540vct at 120ma. I've also got a pair of 100uF Solen's and a pair of gigantic ASC 600uF caps that may be used on the outputs. Whatever doesn't get used on the HA2 clone I'm building too.
_

 

A Wheatfield HA-2 clone?

 I think the NABU case  is calling you...


----------



## whitelabrat

Yes the Wheatfield HA2:

diyAudio Forums - Cheapfield project - Page 1

 I could be really cheap and use a cakepan. Just be sure to wash it first. 
	

	
	
		
		

		
			





 I've just about got a BOM together that I'll post once I've converted it to a useful format.


----------



## TimmyMac

Wow, my Tesla gold pin E88CC's from ebay arrived today... what a difference from the noisy Philips and E-H tubes! Sound is amazing. Highly recommended for $40/pr shipped.


----------



## pabbi1

I owned a HA-2 and HA-1 for several years... loved those amps... but, our wanderlust took them all away from us... <sigh>.

 Knowing where you are with that, the Bijou is a different presentation, and certainly a worthwhile build. In fact, I chose Bijou over Menace (balanced HA-2 was my real aim), so you are in for a treat.


----------



## fishski13

i'm going to purchase 38' of 28 awg solid-silver wire from Partsconnexion tomorrow for hook-up wiring, a set of ICs, and a headphone re-cable for my HD650. will this thin gauge wire be able to handle the Phoenix screws?

 i'm also going to order some Vishay Nudes for the I/O resistors on my attenuator.


----------



## fishski13

i can't believe i just spent $13.91 a piece for 4 "nude" Vishay 100K resistors from texascomponents.com. ouch...i hope they live up to the hype. cotton wrapped solid silver wire ordered as well. 

 the Balanced Bijou continues to impress. no FOTM at chez fishski.


----------



## amphead

Sounds like you are going deep into some Bijou voodooland territory, and I will be interested in the results. 





 Well, I have attached the front panel to the side panels. When the back panel is attached, I will carefully measure for the bottom panel. Edit: some may remember way back in this thread, when I started working on the logo, that I was going to create a backlit badge. This was the reason that I didn't need to use line art. Not that this will be the approach taken by those doing FPE logos, which will be equally stunning.


----------



## regal

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_To use the 6H30's I am assuming you are using a separate filament transformer, because the 6H30's are using at least an amp more current, or is the standard transformer good enough ?_

 


 Can I sub a 6H30 in the input without adding a separate heater transformer or is the 270DAX good enough. The reason I ask is that I haven't known Hammond to even be remotely close to their heater specs. They're usually significantly under rated.


----------



## adamus

I'd suck it and see. if you see a voltage drop, or the tranformer hums/ gets hot then there is problem.


----------



## whitelabrat

EZ80, EZ81... all pricey rectifiers it seems. What if I just used a pair of hexafreds instead? I'll probably need heftier voltage dropping resistors, but should solve any current limitations. Just wondering.


----------



## fishski13

blowing 3.15A fuses shortly after power-up. one of my DAZ 370 transfos gets too hot to touch, the other feels normal. foul electronics smell in the air. any ideas on where to start trouble-shooting?


----------



## whitelabrat

fishski13, is your rectifier tube OK? I'd check there first. I'd also check any regulators in case of a short.

 That's where I'd start.

 I've had trouble with Hammond transformers where they can have a very high voltage surge on power up. Dropping a CL-90 or CL-110 Thermistor on the primaries may help soften the blow to the rectifier tube.


----------



## fishski13

yes, the EZ81 is toast. unfortunately, i also have continuity between the HV 260AC secondary and 6.3AC heaters and CT with the EZ81 removed from the tube socket. are my regulators (Q1,Q2) toast as well? what about the TIP50 on my multiplier PS add-on? how the hell did this spontaneously happen?

 edit: can you accurately test the regulators in circuit?


----------



## amphead

Fishski, sorry to hear about that. I think this is one for the man himself. Runeight? Edit: hey Fishski, I know how you can find it. With the amp powered down and safely discharged, ohm out the boards looking for differences between the working channel and the one not working.Thinking like a mirror image of one another. Otherwise I would start by replacing regulators in the bad channel and the EZ81. I have a funny feeling about the add-on board however, but mostly because I don't know what its doing.


----------



## runeight

fishski, let's start from scratch to try to solve this. As an aside, it could be a delayed result of the earlier problem where you had arcing in the rectifiers (if indeed these are the same tubes).

 First thing, disconnect the transformer from the PS board (all leads). Do you still have continuity between any of the windings?


----------



## huskydawg9

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Can I sub a 6H30 in the input without adding a separate heater transformer or is the 270DAX good enough. The reason I ask is that I haven't known Hammond to even be remotely close to their heater specs. They're usually significantly under rated._

 

Sorry I hadn't got back to you sooner... yes I have an extra transformer for the heaters.. I think it's an:

 166K6 7.56 115V 60 Hz. 6.3 C.T. 1.2 C6H 

 if I remember right.

 I would love for someone to show me something better (single ended wise) than my version of the Bijou with my DDDAC dac (maybe Ferrari's?) . I'm not trying to be cocky... I really want someone to show me something better or any kind of improvement over what I currently have...

 I am so happy with this set up that one day I envision a balanced version of this (when finances can support it)... 

 Alex is the best...in case you haven't figured that out. No one else supports you like he does...

 Actually, I'd like to hear what the fuss about Senn's is all about..cause I really like my Grado's.


----------



## chobint

sorry to hear as well fishski. To throw one possibility into the pool of answers... my ez81 was arcing internally and blowing fuses left and right. I replaced it and have been operating just fine for 500+ hours. Seems to have been a fluke or a bad tube. GL tracing the problem.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_fishski, let's start from scratch to try to solve this. As an aside, it could be a delayed result of the earlier problem where you had arcing in the rectifiers (if indeed these are the same tubes).

 First thing, disconnect the transformer from the PS board (all leads). Do you still have continuity between any of the windings?_

 

i was wondering about the abuse the EZ81 took the first time around with the PS add-on. i don't remember if i replaced it or not. i do have another EZ81, new or abused, i don't know.

 i'm at work right now until 8 am tomorrow. i'll have some time to test the windings before bed and report my findings. 

 thanks for everyones help.


----------



## fishski13

Quote:


  Originally Posted by *huskydawg9* /img/forum/go_quote.gif 
_Actually, I'd like to hear what the fuss about Senn's is all about..cause I really like my Grado's._

 

the K701 sound outfreakin'standing, even without NFB. to my ears, no trouble driving lower impedances in my build, so i would guess that the Bijou could drive Grado proper. i kind of wish i still had my sr-225 now.


----------



## fishski13

with the transfo removed from the offending PS, i have continuity between all secondaries. the foul smell seems to be coming from this transfo as well. like i said before, it got really hot. i can only assume the worst 
	

	
	
		
		

		
			





...


----------



## runeight

I'm sorry fishski, but that transformer is a goner. It's hard to damage a transformer unless there is a dead short somewhere. Are you going to replace it? If so, we'll try to debug the rest of the PS when you're ready.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I'm sorry fishski, but that transformer is a goner. It's hard to damage a transformer unless there is a dead short somewhere. Are you going to replace it? If so, we'll try to debug the rest of the PS when you're ready._

 

i'll wire up the other half of the amp unbalanced for comparison before deciding to shell out for another transfo. while i heard a definite improvement going from unbalanced to balanced, i also replaced the cheap RS pot with my attenuators at that time. we'll see how she sounds unbalanced with the new attenuator.

 i hope my K701s are still functional. they were plugged in the first time i blew a fuse. i think it was the second time i blew a fuse that the transfo died.

 thanks once again. i think i need a drink...


----------



## amphead

Yeah, I hope the phones are OK. You can ohm them out for continuity, eventhough that won't tell you much. Your build looked impeccable, so I'm leaning towards the bad EZ81 as the source of the problem. Too bad it had to take out the trafo, if thats the case. If you rebuild the other channel, you want to make sure that you don't measure low resistance on the output of that channel's PS before powering up. You would want to gingerly try a power-up with fast-blo 1 amp, then fast-blo 1.5 amp and then regular 1 amp fuses on hand, just in case. And maybe 1.5 amp regular fuse depending on how it goes. And your sacrificial phones to start. Quick trigger finger on the power button. But if you want to wait awhile before going balanced again, thats good too. The offer stands as I mentioned before, but you have proven yourself a quite capable builder already.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Yeah, I hope the phones are OK. You can ohm them out for continuity, eventhough that won't tell you much. Your build looked impeccable, so I'm leaning towards the bad EZ81 as the source of the problem. Too bad it had to take out the trafo, if thats the case. If you rebuild the other channel, you want to make sure that you don't measure low resistance on the output of that channel's PS before powering up. You would want to gingerly try a power-up with fast-blo 1 amp, then fast-blo 1.5 amp and then regular 1 amp fuses on hand, just in case. And maybe 1.5 amp regular fuse depending on how it goes. And your sacrificial phones to start. Quick trigger finger on the power button. But if you want to wait awhile before going balanced again, thats good too. The offer stands as I mentioned before, but you have proven yourself a quite capable builder already. _

 

thanks for the re-offer 
	

	
	
		
		

		
		
	


	




. some good news at least - i've rewired for unbalanced and everthing sounds good, including the K701. 

 i think i'll hang here for awhile and wait for my Vishay attenuator resistors and silver signal wire before i make any decisions. i'd like to spend some time unbalanced with a decent attenuator in place. right now, i'm considering my option$ on a different, smaller chassis for unbalanced just in case i decide to leave it unbalanced. 

 btw, i left the PS multiplier mod in place on the working PS. i'm a bit too deflated to try Regals mod right now, but will probably try it down the road - especially if i end up ripping the boards out for a re-chassis.


----------



## amphead

Here is the chassis with 4 sides for the balanced version, I'll get a bottom cut tomorrow.


----------



## pabbi1

How are you cutting the aluminum? Just curious as I am taking on some other casework - looks like you are using solid bar to join the sides?


----------



## amphead

The aluminum, is scrap from a surplus metals store. The front and rear panel were the size that they are when I bought them. The side panels were cut on an industrial hydraulic shear, at the scrap metal store. And the corners are bolted with 1/4 inch aluminum square stock that I hacksawed to size, with quality stainless hardware. It's important to use a punch to mark the drill hole or the holes won't look properly centered. If you have access to a metal blade bandsaw and use a guide, you could get good results Pabbi.


----------



## TimmyMac

So, I Regal-modded my Bijou this afternoon... this thing is unreal! Cymbals, drums, synth, piano, and vocals all come alive. I never knew what this amp was capable of before, but I'm glad I took time out of my B22 build for this.

 Can anyone compare 6N1P to a decent pair (NOS, gold pins) of 6922s? I socketed the cathode resistor while I was in there today and I'm debating picking up some 6N1P-EV.


----------



## amphead

Someone might know, but I haven't had the pleasure as of yet TimmyMac.

 I purchased/had the top and bottom aluminum panels cut to size. I will mount the bottom panel tomorrow if I don't get swamped with obligations for the holidays. Building this case has cost me about $55.00, so not super cheap but it will be strong and have the logo/badge and led eye candy. I might make my own volume knobs this time, because I want large polished aluminum.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Someone might know, but I haven't had the pleasure as of yet TimmyMac.

 I purchased/had the top and bottom aluminum panels cut to size. I will mount the bottom panel tomorrow if I don't get swamped with obligations for the holidays. Building this case has cost me about $55.00, so not super cheap but it will be strong and have the logo/badge and led eye candy. I might make my own volume knobs this time, because I want large polished aluminum._

 

amphead,
 you've inspired me to try DIYing my own enclosures. i'm going to buy a router next week.

 got my wanky silver wire from partsconnexion today. i'll have time tomorrow night to hear what a "silver" Bijou sounds like.


----------



## amphead

Sounds good Fishski!  One warning about wooden cased Bijous. I went through absolute Hexx, trying to get one quiet. As long as you have an aluminum base plate for star ground and use the ground mod, I think you can get where you want to be though.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I might make my own volume knobs this time, because I want large polished aluminum._

 

amphead, making your own is the right path. I've spent (no, wasted) many hours trying to find big volume knobs for sale. When I find one or two, they are usually quite overpriced.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Sounds good Fishski!  One warning about wooden cased Bijous. I went through absolute Hexx, trying to get one quiet. As long as you have an aluminum base plate for star ground and use the ground mod, I think you can get where you want to be though._

 

lined with copper/aluminum is the plan.


----------



## TimmyMac

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_amphead,
 you've inspired me to try DIYing my own enclosures. i'm going to buy a router next week.

 got my wanky silver wire from partsconnexion today. i'll have time tomorrow night to hear what a "silver" Bijou sounds like._

 

DIY case is where it's at.
http://picsorban.com/upload/img_0568.jpg
 It's dead quiet unless I'm using noisy tubes - I grounded both the top and bottom plate, and wrapped the heaters and signal input pair in aluminum foil.


----------



## fordgtlover

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_So, I Regal-modded my Bijou this afternoon... this thing is unreal! Cymbals, drums, synth, piano, and vocals all come alive. I never knew what this amp was capable of before, but I'm glad I took time out of my B22 build for this.

 Can anyone compare 6N1P to a decent pair (NOS, gold pins) of 6922s? I socketed the cathode resistor while I was in there today and I'm debating picking up some 6N1P-EV._

 

I was using a set of green label Amperex Jan 6922s. After reading about how so many people liked the Russian tube, I bought a set. I am now using the 6n1p. I don't feel like I am missing anything by using them. I would say that I didn't really like the sound of the Philips 6922s that I started with, and would imagine that the 6n1p would be a noticeable improvement over them. I haven't bothered comparing them.


----------



## amphead

Sideview with top and bottom just sitting in place.







 Frontview.........vents/component holes will be added as the very last step.


----------



## fishski13

[/IMG]

 soldered in 2 of these nude Vishays last night for series resistors in an unbalanced shunt attenuator. $14 a piece and worth every penny plus more - wildly recommended. i hope some others here will try this. i wonder how these would sound with a PEC or Blue Velvet potentiometer wired for shunt? 

 the TX2352 can be found here Texas Components - Precision Resistor & Microelectronics. great people to deal with, and speedy shipping as well.


----------



## adamus

amphead - how is the casework going? 

 I have spent a day in the shed today (cold!) drilling and filing the chassis for my speaker amp build. 

 I bought some Q.max (similar to greenlee) 3 point chassis punched. So easy to make perfect holes. If you havent got one, i whole heartedly recommend!


----------



## chobint

Hey Alex, do you know what the output impedance of the Bijou is?

 ...and funny you mention that tool adamus, I told my uncle that I needed a tool to make big holes in metal and he ran to his garage and came back and said merry x-mas 
	

	
	
		
		

		
		
	


	




 It does make beautiful holes in thin metal, but I do question it's suitability for cutting things like 10mm front panels.


----------



## runeight

Yep, I have a bunch of those too. And I use them for some holes.

 The Zo of the Bijou is 60R with no NFB (no nfb pot connected).

 With the normal NFB arrangement the Zo is about 20R when the pot is set to its halfway position (125k).


----------



## MoodySteve

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_It does make beautiful holes in thin metal, but I do question it's suitability for cutting things like 10mm front panels._

 

If what you got is a hand punch, it's not going to be of much use on anything thick. I don't use punches on anything thicker than about 3-4mm (1/8") and the punch I had access to was a pedal punch. Something as thick as 10mm should probably be milled.


----------



## amphead

Chobint, the greenlee punch shown, is for thin metal. Unfortunately the thick aluminum front plate needs a dedicated sized drill bit for any large holes. Oil lubricant helps to keep the drill cool while drilling thick plate, and that is the machine shop technique.

 Adamus, my chassis progress is moving very slowly at the moment and should have the bottom plate mounted by the end of the day. I had one of those "roadie" jobs for my nephews band last night. They sounded much better last night than in the show that I posted pictures of. The club didn't reverberate as much, and the lead guitar player wasn't drinking as much beer during his performance, giving a cleaner sound.


----------



## chobint

lol @ amphead's post

 Thanks Alex. I ask about the output impedance because I'm trying to entertain the suitability of the Bijou as a pre-amp. No turn on pop and 60R Zo sounds like it will work just fine.

 And thanks for the info on my new tool. I didn't plan on using it for thick metal, as I expected it would require enormous force and would probably cause undesired distortion in the metal being cut.


----------



## adamus

I think the bijou will hactd to much gain to be honest.


----------



## amphead

Well, almost finished attaching bottom panel and then a pic.

 A little off-topic here, but this is a link for you Fishski. Take a look at the High Octane.

Silvatone Amp Projects


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Well, almost finished attaching bottom panel and then a pic.

 A little off-topic here, but this is a link for you Fishski. Take a look at the High Octane.

Silvatone Amp Projects_

 


 perfect!!!


----------



## fishski13

*Balanced vs Unbalanced - Differences*

 OK...so i fried a transformer (i think i must be the first to ever do this around here in the DIY Forum
	

	
	
		
		

		
			





) and took out one my PS the other week; i have been running unbalanced since then. i have since added some nude Vishays TX2352 in the series resistor of my shunt attenuator in place of the Kiwames, and before that, the RN60s when running balanced. 

Balanced
 K701 - i loved this combo. the bass was smackingly good, mitigating the top end emphasis of this phone, splitting the quanity difference between the K701 and HD650 perfectly. the K701 can be a pretty dull phone, but not so when balanced. timing was very natural and dynamic, never tight-assed or whitey-tighty. music had a pulse. 

 a huge cyrstal clear 3D soundscape. you are in the mix. imaging and sound placement very transparent; pin-point i guess? anyway, soundstage geeks will enjoy. very detailed all the way around. 

 HD650 - much more front-row placement. i guess if i had to say, about as close to unbalanced K701 placement. unfortunately, the bass was waaaay too much in quantity for me for any type of music. as a former double bass player, it sounded grossly overblown, and had no snap whatsoever. it tended to impose itself too much every Hz on up. it worked sometimes with electronica and reggae, but a otherwise a total waste of an excellent phone.

Unbalanced 
 HD650 + K701 - other than the reduction in bass and soundscape, not a huge night and day difference unbalanced. balanced also had a little more finesse with timing and subtle dynamics. unbalanced has a little more drive and forward momentum.

 inserting the nude Vishays in the attenuator changed things up a bit though. i had the balanced 3D soundscaping on the cheap and with a bit more detail as well. there is no overblown bass with the HD650, but the K701 quantity isn't quite what it was when balanced (but still sounds excellent for acoustic recordings). these Vishays are crystal clear, detailed, dynamic, and timbre is spot on. highly recommended if you want to try a shunt pot/attenuator.

 i've decided to stay unbalanced and will be starting a DIY chassis next week. i can't stand the thought of more blown rectifiers, transistor, and transformers. i've been working on this amp for 4 months now and would like to wrap it up in the next month. besides, i'm waiting to see what else Runeight has up his sleeves. as it stands right now, my Bijou has never sounded better, but i'm sure the K701 balanced with these new Vishays in place could be better.


----------



## pabbi1

Yes, the bass in balanced on hd650 is a bit much (maybe needing some bass control, a la m³, well, except in reverse), but with the hd600 I think it is pretty well blended. Anyone who thinks tube amps are bass shy ('rolled off') needs to hear a Bijou.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Yes, the bass in balanced on hd650 is a bit much (maybe needing some bass control, a la m³, well, except in reverse), but with the hd600 I think it is pretty well blended. Anyone who thinks tube amps are bass shy ('rolled off') needs to hear a Bijou._

 

it's been years since i've heard the HD600, but i think it would be a wonderful pairing.

 yes, the Bijou's got cojones.


----------



## amphead

If the balanced Bijou is best with K701, that works for me! I really enjoyed it with Pabbi's HD650's, even with the accent on bass. Bottom panel mounted. Pics later, it's a busy day.


----------



## fordgtlover

My Bijou has nice bass with the K701. I picked up a set of AD2000, and they sound great with the Bijou - very solid bass. In fact, very nice all round.


----------



## amphead

Pic of the chassis with bottom attached. There will be more points with blocks securing in other areas to get maximum rigidity.


----------



## Boilerbots

Hello,

 I quickly built a Bijou amp kit and made this enclosure to give to my brother as a gift. I thought I would share my pictures, might help others decide how to build their Amp.

 The PCB is not exactly layed out to make a good looking amp as designed, so I decided to mount almost all the components on the bottom of the PCB except for the tube sockets, FETs and larger power supply caps. If I was doing it again I might just mount everything on the bottom except the tube sockets, maybe cut a few slots for some convection cooling.

 I did the design in Solidworks, first I modeled the PCBs with components and then built the box to make sure it would fit. The bottom is cut from a sold chunk of ABS plastic, 8x8x2 and the top is a plate of 5051 Aluminum that is easy to polish. This is scrap I had available.

 The top is on standoffs to tweak it, once finished the standoffs come off and the top plate screws to the bottom in the corners. Yes this is easier when you have your own CNC mill.


----------



## holland

Holy crap, that's badass.

 SJ, eh? Do you offer your services? I'm in SJ too. 
	

	
	
		
		

		
		
	


	




 I really hate casework, but you make it look so easy.

 I was going to topmount the PCBs also, but I decided I didn't want screw holes and it would be easier to take off the cover if it was bottom mounted. I've been languishing trying to figure out how to make the measurements to line up the top and bottom, but whatever I come up with is going to be a hair off somehow. Anyhow, I'm going to mount the PCBs on risers, lifted them up about halfway in the case, and then use angle brackets to air wire the tube sockets. The reason for this is that I'm going to flip one of the PCBs over to get the wire routing that I want (symmetry). To be honest, I think (for me) this would be easier as a point to point instead of PCB.


----------



## Boilerbots

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Holy crap, that's badass.

 SJ, eh? Do you offer your services? I'm in SJ too. 
	

	
	
		
		

		
		
	


	




 I really hate casework, but you make it look so easy.

 I was going to topmount the PCBs also, but I decided I didn't want screw holes and it would be easier to take off the cover if it was bottom mounted. I've been languishing trying to figure out how to make the measurements to line up the top and bottom, but whatever I come up with is going to be a hair off somehow. Anyhow, I'm going to mount the PCBs on risers, lifted them up about halfway in the case, and then use angle brackets to air wire the tube sockets. The reason for this is that I'm going to flip one of the PCBs over to get the wire routing that I want (symmetry). To be honest, I think (for me) this would be easier as a point to point instead of PCB._

 

I am in San Jose. I could do another plastic box, the hardest part was the design and generating the CNC program. One minor detail not obvious in the pictures is the very tall caps stick out the bottom of the box just slightly. I am going to stick rubber feet on the corners so they don't touch. There are holes just for those caps. It would be nice to change the PCBs to accept two shorter caps in parallel instead of these really tall caps. The highest components dictate the size of the enclosure.

 It would be possible to use a long standoff and mount the PCBs to the bottom box instead of the top. That would certainly be cleaner but it isn't too bad the way I did it because the standoff threads come up flush to the top of the plate.

 I think you are going to do a lot of work by not mounting the tube sockets on the PCBs. When you are thinking about symmetry just cut the wires the same length. I used the same length wires where it matters. I also coaxial wires for the inputs to the POT and then to the PCB inputs.


----------



## amphead

Nice build Boilerbots! Kudos to using the CNC milling machine. I hope your brother enjoys his new Bijou, when you get it finished.


----------



## amphead

I found some 2 and 1/4 inch, thick wall aluminum pipe, which has 3/8" walls. It is 1 and 1/2 inch inside diameter. I also found 1 and 1/2 inch aluminum round rod to fill the inside snugly. This will be spun on my drill motor and polished with sandpaper to make some 57mm diameter volume knobs. Cutting with a hacksaw will take a while, but where there is a will there is a way. I always liked oversized aluminum volume knobs on stereo equipment.  Edit: I will be putting a bearing in to the front plate for smooth operation of the volume knobs. There will be the backlit Bijou badge in between the L/R volume knobs. When I finish building the volume knobs, I will put pics with a step by step on a new thread for building them from scratch.


----------



## amphead

Two 56mm volume knobs almost finished. My access to a metal cutting bandsaw is limited at the moment, so they were hacksawed by hand and then rotated/polished on my drill press. They are looking very nice, but that much sawing gave me some sore hands.


----------



## runeight

We wait . . .


----------



## srserl

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Two 56mm volume knobs almost finished. My access to a metal cutting bandsaw is limited at the moment, so they were hacksawed by hand and then rotated/polished on my drill press. They are looking very nice, but that much sawing gave me some sore hands. _

 

If you need to saw more, I'll bring my super sawz-all over...I can't believe you did 56mm by hand (x2)!!!

 Scott


----------



## Boilerbots

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Two 56mm volume knobs almost finished. My access to a metal cutting bandsaw is limited at the moment, so they were hacksawed by hand and then rotated/polished on my drill press. They are looking very nice, but that much sawing gave me some sore hands. _

 

I don't know where you live, but if it is within driving distance of San Jose I could turn a knob on a lathe for you.


----------



## amphead

Thanks for the offer Srserl! And thanks for the lathe access Boilerbots! I may take you up on some short runs, if my local access(Sacramento area) falls through. A friend that I see once in awhile works in a high-tech medical instrumentation machine shop. Don't know if he would get into trouble if we went in after hours. 

 Runeight, esteemed peers, here it is...........


----------



## V-DiV

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Runeight, esteemed peers, here it is..........._

 

Amphead, how did you bond the rod inside the pipe?


----------



## V-DiV

Hi everybody. I just ordered a Bijou kit from Jeff at GlassJar. I’ve already read this thread more than once through in deciding what amp to build next. Now that I’ve decided, I’ll go back through to glean as much as I can to help finalize the details of my build (and the Cavalli Audio website too). I would be happy if anyone wants to jump in with any preemptive advice. I’m particularly going to be looking for:

 1) Should I do Regal’s mod from the start?

 2) Capacitors: especially, what reasonably priced solutions will tame the large output caps. I listen to classical and jazz, with some bluegrass, newgrass, blues, and rock through K701s (low Z).

 - Should I buy shielded hookup wire? If so, does the shielding need to be grounded? Use it for everything or just certain things?

 3) Should I use a beefier transformer than the 270 DAX (370 DAX?) in case I want to go balanced or will I need two transformers for balanced? What was that R-core transformer?

 4) I gather that ample room is needed inside the case for keeping the high voltage leads (and transformer obviously) away from the amp boards to eliminate hum.

 5) I’ll have to decide what to do for a case. I am fond of the BottleHead style with the wood frame around the sides and the metal plates top and bottom (who made a Bijou like that, TimmyMac? and runeight’s PTP prototype) but I decided not to do PTP and I’m not that excited about the tubes half out by bottom mounting components and raising the boards just under the top (especially the power supply tube just peaking out). Can all the tubes be air-wired without detriment to the sound? How? Ferrari must know how.

 6) What else???


 Thanks in advance.


----------



## amphead

The inner rod has been epoxied to the outer pipe. I roughed up the surfaces with sandpaper first though. Those building a knob, would have the option of drilling a side hole and threading for 4/40 to have a traditional knob. My knobs are epoxied to the 1/4" stainless rod. The rod will ride in a bronze bearing through the front panel, lubricated with machine oil.

 No reason not to do Regals mod first, and yes the case needs ample room for heat and to help route wiring properly to avoid hum. Shielded wire on the input wiring with grounds directly to star ground. You might also shield output wiring depending on your noise floor.


----------



## pabbi1

Ron, get some meat on that sandwich... and make up a couple extra badges... 
	

	
	
		
		

		
		
	


	




 As far as recommendations, Obbligato has some new caps, where serevral have used rather exotics on c6.

 There is also the issue of socketing R2 which lets you roll through different tubes, which is also a choice you have to make. Oh, and make sure you start looking at tubes you might want to try - that is half the fun, though the Russian tubes can take a while to settle in (ime).

 Do not scrimp on your attenuator - TKD, or (gulp) eBay stepper, at some point - the R27, while serviceable, really holds this amp back. 

 Finally, take your time, ask questions, and we all have pictures - no one on this thread is shy about sharing images, and offering advice, expecially Alex, the creator.

 Others will have to contribute, but you will always get feedback - usually good, sound feedback, all from experience, not just 'from what I've read' stuff.


----------



## TimmyMac

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_1) Should I do Regal’s mod from the start?

 2) Capacitors: especially, what reasonably priced solutions will tame the large output caps. I listen to classical and jazz, with some bluegrass, newgrass, blues, and rock through K701s (low Z).

 3) Should I use a beefier transformer than the 270 DAX (370 DAX?) in case I want to go balanced or will I need two transformers for balanced? What was that R-core transformer?

 5) I’ll have to decide what to do for a case. I am fond of the BottleHead style with the wood frame around the sides and the metal plates top and bottom (who made a Bijou like that, TimmyMac? and runeight’s PTP prototype) but I decided not to do PTP and I’m not that excited about the tubes half out by bottom mounting components and raising the boards just under the top (especially the power supply tube just peaking out). Can all the tubes be air-wired without detriment to the sound? How? Ferrari must know how.
 Thanks in advance._

 

1. yes
 2. I'm interested to know this too
 3. 270DAX is lots for an unbalanced build. You need something bigger for balanced, or two if you want to go dual-mono. R-core is available here: Audio Catalog the R0080-036 *might* be sufficient for a balanced build, but I wouldn't recommend Regal's mods or hotter tubes like 6n6p's on it with 4 amp boards.
 5. Yes, I did a wood-cased one. There's pictures around somewhere - I posted one 2-3 pages back - but I think it turned out pretty well. My recommendation is definitely to mount the boards on the top panel and all the components on the underside of the board. My setup with air-wired tubes is fine and gives you a smoother top panel and allowed me to put the tubes where I wanted, but it's a pain in the ass to unscrew the sockets with only the length of the air-wires to reach under the top panel with!


----------



## chobint

Impressive work amphead. I can't wait to see it finished. I don't remember if you mentioned this yet...will you be going the pcb or air wire route with this one?

 As for output caps, I am very pleased with my mundorf 330uf poly caps... but you could probably get by with 150uf or 220uf with k701's, giving -3dB points of ~17hz and ~12hz respectively.


----------



## fishski13

Amphead,
 looks great!!! yes, we wait....

 i finally bought a router, DeWalt DW621. i have a pretty hunk of maple for the side panels. i've found a local aluminum supplier that i'm hitting tomorrow, Discount Steel - The widest selection of steel, aluminum and other metals at discount prices.. pabbi1, these guys are "local" for you as well. also bought a nice non-ferrous blade for the chop box, Freud. i could have built a nice Bijou for the cost of what i've spent on tools to slap together a homebrewed chassis. 

 the Bijou, M3, and Mini3 are all getting chassis make-overs and parts upgrades. 





 (my beard is not quite as long. this guy's could be a hazard around a router, or a spagehtti fork for that matter.)

 V-Div, 
 welcome to Club Bijou - i hope you enjoy your stay. 

 SIP sockets for resistor pad/leads are your friends. consider using these in the NFB circuit as well - R2 is a no brainer. i think pabbi1 played with the NFB circuit a bit. read this thread again. 

 pabbi1,
 you've converted me into an "attenuator nerd". the R27 is a real let down. i've ordered a PEC for my M3. i will also try some nude Vishays in shunt configuration as well.


----------



## adamus

that is quite simply an amazing beard.


----------



## pabbi1

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_Amphead,
 looks great!!! yes, we wait....

 i finally bought a router, DeWalt DW621. i have a pretty hunk of maple for the side panels. i've found a local aluminum supplier that i'm hitting tomorrow, Discount Steel - The widest selection of steel, aluminum and other metals at discount prices.. pabbi1, these guys are "local" for you as well. also bought a nice non-ferrous blade for the chop box, Freud. i could have built a nice Bijou for the cost of what i've spent on tools to slap together a homebrewed chassis._

 

Yes, though Ft Worth is still about 50 miles from me, though they do have copper (wink) and titanium also, in addition to a lot of tasty aluminum. But, I just bought $1000 in aluminum, and will look at a couple hundred more this weekend... MULTIPLE casing projects... <sigh> 

  Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_pabbi1,
 you've converted me into an "attenuator nerd". the R27 is a real let down. i've ordered a PEC for my M3. i will also try some nude Vishays in shunt configuration as well._

 

Hearing really is believing, though sometimes, the RK27 is 'good enough', but, just not here. I looked at the PEC, but just had to go with the TKD P-2500, but still think the Bijou is worth the TKD P-65... not quite RK50 territory, though.


----------



## fishski13

Discount Steel is a 10 min drive. they have "drop" cuts in various sizes at $3/lb. i bought a 2'x2', 1/4", 5052 plate, and a 2'x4', 1/8", 5052 sheet: 15# total, and with tax came to $48. if you custom order these sizes on the web, the total comes to $114. it may be worth your time and gas to pick up some drop cuts. also, they are very friendly and helpful. i highly recommend them to anyone looking for metal, and they also have a very user friendly website.

 wood and aluminum chips are gonna fly tonight.


----------



## pabbi1

Completely agree, they have a range of great stuff, but someone is tempting me with six (6) 144" x 36" sheets of .25 6061, for $100 a sheet (~$3 sf)... too tasty. Just gotta figure out how to get it home... after I get my 376 lbs in from Colorado. 
	

	
	
		
		

		
		
	


	




 I am SERIOUSLY looking at copper plate in .125", if they'd ever have a piece big enough.

 Might well have to recase the Bijou, but not for a bit.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Completely agree, they have a range of great stuff, but someone is tempting me with six (6) 144" x 36" sheets of .25 6061, for $100 a sheet (~$3 sf)... too tasty. Just gotta figure out how to get it home... after I get my 376 lbs in from Colorado. 
	

	
	
		
		

		
			





 I am SERIOUSLY looking at copper plate in .125", if they'd ever have a piece big enough.

 Might well have to recase the Bijou, but not for a bit._

 






 that is friggin' cheap. i'd say that would call for a road-trip and a trailer.


----------



## amphead

Quote:


 Might well have to recase the Bijou, but not for a bit. 
 

Yes, I can create a couple extra Bijou badges for backlit purposes. Dont know if they will be glass front or acrylic front.

 Fishski, sweet looking router!

 Kanobs are ready to install through the front panel tonight. Thanks for lookin.

 Going for the old Sansui/Marantz look.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_






 Yes, I can create a couple extra Bijou badges for backlit purposes. Dont know if they will be glass front or acrylic front.

 Fishski, sweet looking router!

 Kanobs are ready to install through the front panel tonight. Thanks for lookin.

 Going for the old Sansui/Marantz look._

 

keep me posted re: backlit Bijou badge. what are the dimensions? what final design/drawing did you settle on? i'm game as long as there's no mention of "balanced" on the badge 
	

	
	
		
		

		
		
	


	




. maybe i'll need 2 badges in case my SE chassis clones another down the road. Bijou mono-blocks for balanced 
	

	
	
		
		

		
		
	


	




?


----------



## luvdunhill

Alex:

 I'm wondering why some designers put a very small capacitor (i.e. 10pF) in parallel with the negative feedback resistors? I've seen this on the Leech amplifier for example. I'm curious what the function of this capacitor is, and in what types of applications it is recommended. Can it be used to reduce the output capacitance needed, for example, or perhaps used in lieu of a DC servo?


----------



## adamus

Inverting Amplifier Feedback.

 that may shed some light.


----------



## luvdunhill

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Inverting Amplifier Feedback.

 that may shed some light._

 

yeah, nice link 
	

	
	
		
		

		
		
	


	




 answers my questions, except for why doesn't everyone do this.


----------



## pabbi1

Fishski, what is Discount Steel's eBay store (originally found them that way, but can't atm)?

 Oh, yes, still loving the Bijou - warmed up, and ready to go head to head with a balanced beta22 in two weeks. We will see what is what, with neutral observers weighing in.


----------



## digger945

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Oh, yes, still loving the Bijou - warmed up, and ready to go head to head with a balanced beta22 in two weeks. We will see what is what, with neutral observers weighing in. 
	

	
	
		
		

		
		
	


	


_

 

Now that sounds like fun
	

	
	
		
		

		
		
	


	




.

 What did you finally settle on for an attenuator?


----------



## runeight

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_yeah, nice link 
	

	
	
		
		

		
		
	


	




 answers my questions, except for why doesn't everyone do this._

 

This should probably be done more often than it is, but many casual designers may not understand the phasing problem around the feedback loop. 

 There are usually two ways that the HF instability is removed. The closed loop compensation is one way. There is also open loop compensation which is usually applied at the main voltage gain stage (in many transistor amps, the VAS). This cap causes the gain to drop quickly above the chosen corner frequency so that the amp just doesn't have any gain with which to oscillate. Then, if needed, the close loop compensation is also added. 

 In a sand amp using the most typical topology you'll see the open loop compensation cap called Cdom and it sits between the base and collector of the primary gain device (or gate/drain). At HF this cap shorts the base to collector steadily reducing the gain of the transistor (or mosfet) with increasing freq.

 Thus, for the HF loop to be a problem the amp actually has to have bandwidth high enough to amplify in that region. If the HF bandwidth is not high enough the closed loop compensation may not be needed. The Bijou's HF response is not super high because of the tubes, so the NFB issue is much less of an issue. However, I actually did test this condition and was able to make the Bijou oscillate by lowering the value of the first grid stopper. The 10k value puts the amp well away from an unstable regime without additional compensation.

 Does this help?


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Fishski, what is Discount Steel's eBay store (originally found them that way, but can't atm)?

 Oh, yes, still loving the Bijou - warmed up, and ready to go head to head with a balanced beta22 in two weeks. We will see what is what, with neutral observers weighing in. 
	

	
	
		
		

		
		
	


	


_

 

i had no idea they had an eBay store. i've only jibbed around on their www.


----------



## luvdunhill

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Does this help?_

 

yes, this definitely helps. So, with regard to HF LPF rolloff grid stopper resistor solution compared to compensation capacitor from the plate to grid in a tube output stage, what are the pros and cons of addressing oscillation these two ways? 

 It seems that there are 3 different knobs here to address this problem, and it's hard to know whether one turns up a single knob high enough to solve the problem, or turn more than one knob up slightly...

 Also, how did you test this condition on the Bijou, via SPICE or the actual circuit? It seems that this is one of those cases where SPICE might not tell the truth, or at least that happened with a solid state amplifier I built..


----------



## adamus

I doubt you could simlulate the bijou in spice. 

 My guess is alex put a low gridstopper in, and scoped it.


----------



## pabbi1

Quote:


  Originally Posted by *digger945* /img/forum/go_quote.gif 
_Now that sounds like fun
	

	
	
		
		

		
		
	


	




.

 What did you finally settle on for an attenuator?_

 

TKD P2511 (the PartsConnexion 'Alps' taper), which sounded like 'sand' initially, but really straightened out after about 100 hours or so, most of which was after about 20 hours... but, initially, they sounded like poo.

 I am scared beyond reason that Marc poked in here... after being at my house, and not getting a listen to the Bijou, at all... 
	

	
	
		
		

		
		
	


	




 'Course, we had electrostats to fry...


----------



## V-DiV

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Oh, yes, still loving the Bijou - warmed up, and ready to go head to head with a balanced beta22 in two weeks. We will see what is what, with neutral observers weighing in. 
	

	
	
		
		

		
		
	


	


_

 

I can't wait to read those impressions.


----------



## amphead

I will give a brief spoiler of balanced Beta22 vs balanced Bijou. It will be brief because I highly respect both designers and applaud them for the results of their hard work. And having enjoyed the results of their work so thoroughly, it makes it difficult to find any negative aspects for the review. So, when I attended the Burning Amp event, the balanced Beta22 was hooked up to some quality speakers for about an hour. It filled the air with some of the richest and effortless sound, that I have ever heard. Incredible detail and soundstage. The music was extremely lively and timing was right on the money. There was a nice balance between treble and bass. With plenty of tight bass on hand. Strings/violins resonated realisticly. The balanced Beta22 should not be used with speakers without large heatsinks in the output stage however, because of the large power dissipation there. It is designed as a headphone amp. In comparison, the balanced Bijou with Pabbi's HD650 headphones, had an extraordinarly spatial sound with deep bass, prominent but smooth mids, and great extension with the high frequency range, giving vocals and acoustic guitar a spine tingly timbre. There is a great presence of being there with the artist. It is engaging and you get lost in the music. It is not fatiguing, and you want to listen for hours(usually 4 for me). Both amplifiers run with a fair amount of heat, and it is necessary to keep that in mind when building either. I will leave it to Pabbi to do a head to head on phones.  Edit: I would love to hear the balanced Bijou with some super efficient speakers, but probably never will due to the price and the fact that the load impedance would be too low at only 8ohms per channel, effecting linearity and current consumption.


----------



## amphead

Oooh........nice knobs.


----------



## runeight

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_yes, this definitely helps. So, with regard to HF LPF rolloff grid stopper resistor solution compared to compensation capacitor from the plate to grid in a tube output stage, what are the pros and cons of addressing oscillation these two ways? 

 It seems that there are 3 different knobs here to address this problem, and it's hard to know whether one turns up a single knob high enough to solve the problem, or turn more than one knob up slightly...

 Also, how did you test this condition on the Bijou, via SPICE or the actual circuit? It seems that this is one of those cases where SPICE might not tell the truth, or at least that happened with a solid state amplifier I built.._

 

Yep, adamus is right. This does not show up in Spice. I just started reducing the value of the stopper until it oscillated. It was not hard to detect as the amp pretty much stopped working and I could hear the tubes singing.

 Generally there are two knobs, the open and close loop gain behaviors. Adjusted as I mentioned.

 In the Bijou case there is another effect that matters that is essentially equivalent to the Cdom cap on the VAS stage.

 In the Bijou, the only gain comes from the first stage. The Miller capacitance between the grid and plate is, essentially, the Cgp mulitplied by the gain of the stage which is about 25. I don't recall the Cgp for 6922, but if it's 3pf then the Milller capacitance is 75pf. Now the Miller capacitance is identical to the Cdom cap that is introduced to reduce the HF open loop gain. So we've already got a sizeable Cdom cap built into the first stage. 

 In addition to this the grid stopper resistor and the Miller capacitance act like a low pass filter. The bigger the grid stopper the lower the corner frequency. With no NFB this would just change the HF rolloff, but with feedback it affects the closed loop gain and the phasing. Reducing the grid stopper resistor increases the rolloff frequency giving the amp more gain at high frequencies. In the case of the Bijou, with the phase shifts introduced by the phase splitter and output stages, increasing the closed loop rolloff frequency by lowering the value of the stopper eventually causes the amp to oscillate. Increasing the grid stopper prevents this closed loop oscillation by doing just what a grid stopper is supposed to do.

 10k is sufficiently high to prevent oscillation under all conditions while permitting a nice range of NFB with a reasonable pot.

 BTW, sand devices have Miller capacitance too. Mosfets, because of their Cgd can have quite a lot.


----------



## V-DiV

That Sansui receiver is a beauty. Is that an old picture from when it was new, when, back in the 1970s or has it been kept so beautifully? Four level meters - Quadrophonic?

 My Bijou kit will be arriving from Glass Jar in a couple of days, but I still need to order resistors for Regal's Mod. Does anyone have a Mouser (or wherever) parts list for these as well as the variants for R2? Need 10k@1W; 30K@2W; 487, 180, and 1.3k @ 1/4W 1% metal film. Can only find metal oxide for the 2W R3. Is that ok? I was looking through the Mouser catalog and the higher watt resistors needed are mostly longer than the 10-12 mm lead spacing called for in runeight's parts list. Is that a big deal? Also, I'm not sure what to look for in sockets for R2. Thanks, Vic


----------



## Forte

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_TKD P2511 (the PartsConnexion 'Alps' taper), which sounded like 'sand' initially, but really straightened out after about 100 hours or so, most of which was after about 20 hours... but, initially, they sounded like poo.
_

 

pabbi1 are you using the standard 2CP-2511 or PCX's 2CP-2508 Alps A taper? And how does it compare to an Alps or cheap stepped attenuator?

 I bought a set of Bijou boards in the original group buy and have been slowly collecting parts as finances have allowed. Now have just about all the parts to start building and was planning to use a spare Alps pot I have. Is it worth the extra to get a better pot?


----------



## pabbi1

Quote:


  Originally Posted by *Forte* /img/forum/go_quote.gif 
_pabbi1 are you using the standard 2CP-2511 or PCX's 2CP-2508 Alps A taper? And how does it compare to an Alps or cheap stepped attenuator?

 I bought a set of Bijou boards in the original group buy and have been slowly collecting parts as finances have allowed. Now have just about all the parts to start building and was planning to use a spare Alps pot I have. Is it worth the extra to get a better pot?_

 

Well, 'worth it' is different for everyone, and many will tell you the rk27 is just dandy. Have a gander at this thread, where the illuminati all weigh in. I have had varying degrees of success with eBay steppers, though the NON-smd have given me the best results. I did indeed get the P2508, where many others like the straight P2511, preferring to save the cash.

 Vic, since I didn't do the Regal mod (maybe I should do a retrofit), but generally, if you cannot find resistors at Mouser, there are several honey holes to try. First is PartsConnexion, second is Soniccraft, my third choice (takes a little patience) is Nebraska Surplus Salas, and, of course, good old eBay has several Asian parts stores, and a few US guys. Michael Percy (Percyaudio) also has anything you need, but I have never ordered anything from him.

 There are others, but far be it from me to be able to remember them all...


----------



## fishski13

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_That Sansui receiver is a beauty. Is that an old picture from when it was new, when, back in the 1970s or has it been kept so beautifully? Four level meters - Quadrophonic?

 My Bijou kit will be arriving from Glass Jar in a couple of days, but I still need to order resistors for Regal's Mod. Does anyone have a Mouser (or wherever) parts list for these as well as the variants for R2? Need 10k@1W; 30K@2W; 487, 180, and 1.3k @ 1/4W 1% metal film. Can only find metal oxide for the 2W R3. Is that ok? I was looking through the Mouser catalog and the higher watt resistors needed are mostly longer than the 10-12 mm lead spacing called for in runeight's parts list. Is that a big deal? Also, I'm not sure what to look for in sockets for R2. Thanks, Vic_

 

metal oxide is fine. 

 for socketing, you need SIP sockets:
310-13-120-41-001000

 i think i had to "tombstone" only R7 and R8 on the PS board. i think i used Vishay RN55 everywhere else without lead spacing issue.


----------



## luvdunhill

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Generally there are two knobs, the open and close loop gain behaviors. Adjusted as I mentioned._

 

Thanks for your help Alex. So, given the worse case scenario (untrimmed DC offsetS for example) what sort of voltage ratings are appropriate for the compensation capacitors from grid to plate as well as the capacitors in the feedback loop?


----------



## runeight

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_Thanks for your help Alex. So, given the worse case scenario (untrimmed DC offsetS for example) what sort of voltage ratings are appropriate for the compensation capacitors from grid to plate as well as the capacitors in the feedback loop?_

 

Do you have a particular circuit in mind? At his point it would help to see it. PM me if that's prefereable. Or email me directly if you have my email address.


----------



## chobint

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Can only find metal oxide for the 2W R3. Is that ok? I was looking through the Mouser catalog and the higher watt resistors needed are mostly longer than the 10-12 mm lead spacing called for in runeight's parts list. Is that a big deal?_

 

As I recall, R3 is the one large resistor on the board and is given a little extra space. I used this 30k 2W 5% for my R3 and it fits just fine.

  Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Four level meters - Quadrophonic?_

 

If that Sansui is like most analog radio receivers, those four meters indicate left level, right level, tuning accuracy and radio signal strength.


----------



## amphead

That Sansui receiver was something for sale on Ebay a while ago. I think it went for $350.00

 Here are a couple of pics with knobs temporarily mounted into the front panel. They are going to lose 2mm off of their diameter and 4mm off of their thickness. Fairly easy to do mounted in the drill press.


----------



## V-DiV

Amphead, how's the casework coming?

 Thanks Pabbi, fishski, and Chobint. I put in an order to Mouser for resistors for Regal's Mod and for tube rolling, Wima's for C6, jacks, power inlet, and some odds and ends. Also ordered a pair of 6DJ8. Next up is wire, transformer, and decision on case.

 I would like to build the amp boards upside down under the top plate and air wire the tube sockets. TimmyMac soldered straight to the boards for his air wire. It looks like Ferrari soldered sockets to the boards and wired from the sockets - does that make for a less positive contact? 

 If the PS board is upside down will the FETs get too hot? Can I air wire those too and mount them on top with the tubes (and tranny) like on my Starving Student Millett? 







 or will all of that air wiring likely result in hum or signal degradation problems regardless of how carefully routed? If it is a problem, would shielded wire fix it?

 Thanks,
 Vic


----------



## balderon

I am considering building the Bijou but I am concerned about driving low Z phones (Denon d5K). I have read multiple posts describing some ideas for mods but I have not read any opinions about how the phones sound. I would appreciate if anyone would share their impressions and amp configuration (tube/caps/etc)?


----------



## amphead

You will be driving 25 ohm phones, therefore it requires a fair amount of negative feedback. It can be done successfully, and I would recommend installing the NFB pot, to allow you to dial in the sound that best suits the Denon AH-D5000 phones. Obligato, Mundorf silver/oil, Auricap are some recommended films for bypassing the output caps, which will probably be lytics, due to the cost of large films. If you decided to give it a go, welcome to the Bijou club! 

 Edit: I have resized one of my volume knobs and polished it to a near mirror finish with automotive finishing polish. Pics when both are done and mounted.


----------



## regal

I hate turning off my Bijou because I can never predict when I will want to listen to it and don't like waiting for the warm up.

 This is expensive when using Aperex 6DJ8 tubes. Is there an easy way to wire the standard transformer to power the 12V heated Aperex 8416's ?


----------



## adamus

if by standard you mean hammond with a single 6.3v ct secondary then i dont think so. Its possible with the R core as it has 2 6.3v secs.

 a very easy way would be to use a small 12v tranformer. Unregulated it will put out about 12.6v anyway if its a bit over capacity.


----------



## balderon

Thank you amphead for the pointers. Please excuse my ignorance but I have a few more questions.  A post by Ferrari mentioned the 470uf output cap is theoretically adequate for low Z phones. I assume that is possible by significantly increasing the negative feedback and because the high frequencies are bypassed at the output caps. I have minimal experience with tube amps and how does one know the appropriate amount of feedback to apply?

 Applying Ferrari's equation to compute the –3dB point I calculated ~1100 uF needed for the output caps. Should the output e'lytic cap be increased to this size? If so, do you know of a quality 250v e'lytic you could recommend (I did not find any Nichicon muse caps with sufficient voltage ratings)?

 If the output cap size is increased, is there an equation for calculating the size of the cap for bypassing the output caps?

 I apologize for the audio-101 questions . My expertise is in the digital domain not analog. Can anyone recommend any books/websites that would help me come up to speed. I do have a EE/CS background and I am a quick study!

 Thank you.


----------



## amphead

You should be ok with the caps that I used 410uF 300v.

RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 360080999665 end time Feb-15-09 18:13:28 PST)

 I substituted 1/2" shaft for the 1/4" shaft on my knobs. It is mounted through 1/2" bronze bearing. Moves smoother with the teflon washers I installed.

 Edit: Alex Cavalli is mentioned in the Jan. 2009 issue of HiFi News. On sale at Barnes and Noble.


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_
 Edit: Alex Cavalli is mentioned in the Jan. 2009 issue of HiFi News. On sale at Barnes and Noble. _

 

Umm, are they talking about me? If so, what are they saying? I guess I'll have to go to B&N and buy a copy.


----------



## pabbi1

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_You should be ok with the caps that I used 410uF 300v.

RUBYCON PHOTO FLASH / STROBE ELEC CAPACITOR 410UF 300SV - eBay (item 360080999665 end time Feb-15-09 18:13:28 PST)

 Edit: Alex Cavalli is mentioned in the Jan. 2009 issue of HiFi News. On sale at Barnes and Noble. _

 

BTW, I still have PLENTY of those caps for Bijou builders... do not pay the ebay price. Search the thread for details. Basically, I will send you a cap for every $1 donated to Head-fi, and I pay shipping.


----------



## runeight

Egads, I went to both B&N that are near my house. They carry Hi-Fi News but they don't have any copies!!!!


----------



## dBel84

someone is going to have to post an excerpt, I am dead curious now ..dB


----------



## wiatrob

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Egads, I went to both B&N that are near my house. They carry Hi-Fi News but they don't have any copies!!!!_

 

Same here, stopped at one on the way home and there were no copies left. The Cult of Cavalli must have wiped them out! Prepare for a rush of builds!


----------



## runeight

I simply have no idea what this is all about, but I hope they said something good.


----------



## TimmyMac

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_BTW, I still have PLENTY of those caps for Bijou builders... do not pay the ebay price. Search the thread for details. Basically, I will send you a cap for every $1 donated to Head-fi, and I pay shipping._

 

If these things are a significant upgrade from the stock caps, sign me up. I've been wondering about that big electrolytic, and what I can do about it. Are there any other suitable options? I'm sure it's covered somewhere in this thread, but there's a few hundred pages now


----------



## fishski13

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Amphead, how's the casework coming?

 Thanks Pabbi, fishski, and Chobint. I put in an order to Mouser for resistors for Regal's Mod and for tube rolling, Wima's for C6, jacks, power inlet, and some odds and ends. Also ordered a pair of 6DJ8. Next up is wire, transformer, and decision on case.

 I would like to build the amp boards upside down under the top plate and air wire the tube sockets. TimmyMac soldered straight to the boards for his air wire. It looks like Ferrari soldered sockets to the boards and wired from the sockets - does that make for a less positive contact? 

 If the PS board is upside down will the FETs get too hot? Can I air wire those too and mount them on top with the tubes (and tranny) like on my Starving Student Millett? 







 or will all of that air wiring likely result in hum or signal degradation problems regardless of how carefully routed? If it is a problem, would shielded wire fix it?

 Thanks,
 Vic_

 

i'm not sure that there's any specific answers other than following the general rules about heater wiring and thermal management. in DIY, you have to suck it and see, and be prepared to be flexible to make layout/wiring changes if need be. 

 if mounting the PS FETs underneath, i would personally add a taller heatsink if you have the room - they get hot. i've posted my experiences dealing with heat and power dissipation with the multiplier mod i performed on my PS in this thread. i wouldn't be comfortable mounting the FETs to the chassis either.

 i also played around a bit with running multiple LEDs over a distance for some trick lighting effects. since the LEDs carry heater AC, they will carry noise as well. with no attenuation, source connected but no signal, heater noise was audible and changed in volume depending where i moved the LED wire. the least offensive was with the wire going straight up, perpendicular and away from the PCB. but heater noise was inaudible with attenuation at sane volume settings, so not an issue. i'm not suggesting that you don't air wire an LED or tubes, but rather to illustrate a point.

 i would do Amphead's Mod and add shielding to the air wired heaters if needed.


----------



## balderon

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_If you decided to give it a go, welcome to the Bijou club!_

 

Thanks! I have decided to join the club.


----------



## Dantes

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_BTW, I still have PLENTY of those caps for Bijou builders... do not pay the ebay price. Search the thread for details. Basically, I will send you a cap for every $1 donated to Head-fi, and I pay shipping._

 

I did not follow all the discution.
 Theses caps are intended to replace C5 ? 
 What changes this will introduce ?


----------



## Ferrari

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_Thank you amphead for the pointers. Please excuse my ignorance but I have a few more questions.  A post by Ferrari mentioned the 470uf output cap is theoretically adequate for low Z phones. I assume that is possible by significantly increasing the negative feedback and because the high frequencies are bypassed at the output caps. I have minimal experience with tube amps and how does one know the appropriate amount of feedback to apply?

 Applying Ferrari's equation to compute the –3dB point I calculated ~1100 uF needed for the output caps. Should the output e'lytic cap be increased to this size? If so, do you know of a quality 250v e'lytic you could recommend (I did not find any Nichicon muse caps with sufficient voltage ratings)?

 If the output cap size is increased, is there an equation for calculating the size of the cap for bypassing the output caps?

 I apologize for the audio-101 questions . My expertise is in the digital domain not analog. Can anyone recommend any books/websites that would help me come up to speed. I do have a EE/CS background and I am a quick study!

 Thank you._

 

Balderon, I have written that post by head and by looking at the actual output schematic of the Bijou, with headphone connected.

 The bypass cap is intended to lower the ESR of the main output cap and has no (negligible) impact on the cut-off frequency (-3dB point). The amount of negative feedback is intended to reduce the effective gain of the amp when desired (not implemented in mine) and has also no impact on the cut-off frequency (-3dB point).

 You didn’t say what kind of headphone you are going to use, but based on your descriptions I think that it’s probably 32Ω or lower and you have the cut off frequency of ~5Hz in mind (?). 
 An output capacitor of 470µF will indeed result in a higher cut-off frequency, but it can work. 
 Personally I’m using ~400µF MKP with AKG K701 and have not experienced any lack of bass.
 As for output cap, I think that “quality” is ruling over “quantity” (with a reasonable value).

 If you are interested in some readings you might try this link, and especially about passive filter, take a look here.

 Btw, no need to apologize. Many (or may be most) of the DIY folks at this place don’t have much expertise in EE, no matter analog or digital (sometimes… even folks who has done 10 projects) 
	

	
	
		
		

		
		
	


	




.


----------



## amphead

Yes, good point Ferrari!

 Alex, would you like me to get you a copy of HiFi News and send it? As I remember, Jeff Rossel brought his Bijou to Burning Amp and displayed it at Amb's table. The magazine reporter mentioned that it was your design in the article. Amb was also mentioned in the same article.

 Well I have drilled a 1.25" hole in the front panel and installed a 1/2" precision bearing. That volume knob rotates as smooth as silk. I have to do that for the other volume knob now. This added another $25.00 to the cost of the chassis.


----------



## runeight

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Yes, good point Ferrari!

 Alex, would you like me to get you a copy of HiFi News and send it? As I remember, Jeff Rossel brought his Bijou to Burning Amp and displayed it at Amb's table. The magazine reporter mentioned that it was your design in the article. Amb was also mentioned in the same article.

 Well I have drilled a 1.25" hole in the front panel and installed a 1/2" precision bearing. That volume knob rotates as smooth as silk. I have to do that for the other volume knob now. This added another $25.00 to the cost of the chassis._

 

Thanks amphead. Let me try a few more place here in Austin. And then if I run out of sources I may take you up on your kind offer.


----------



## luvdunhill

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Thanks amphead. Let me try a few more place here in Austin. And then if I run out of sources I may take you up on your kind offer._

 

I'd try Book People downtown, Border's in the Domain, and Barnes and Nobles in the Arboretum... If I see it, I'll let you know


----------



## Dantes

I do not remember if the information is in this thread and i do not have the courage to search in 147 pages, so i ask.

 Have someone have made some measure of the max output with différent impedence load ?


----------



## runeight

Thanks. I found a copy. I'll check it out later.


----------



## runeight

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_I do not remember if the information is in this thread and i do not have the courage to search in 147 pages, so i ask.

 Have someone have made some measure of the max output with différent impedence load ?_

 

In its most typical configuration the Bijou maxes out at about 40mA peak. With the 6N6Ps running a little hotter, maybe bit more -- with ECC99s a little bit less.

 Theoretically this means . . .

 For 32R:

 .04 * .04 * 32 / 2 = 25mW RMS (50mW peak)

 For 300R:

 .04 * .04 * 300 / 2 = 240mW RMS

 I have not heard of someone doing an actual measurement, but I think it would be close to these numbers.


----------



## Dantes

ok, thanks a lot


----------



## balderon

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_You didn’t say what kind of headphone you are going to use, but based on your descriptions I think that it’s probably 32Ω or lower and you have the cut off frequency of ~5Hz in mind (?). 
 An output capacitor of 470µF will indeed result in a higher cut-off frequency, but it can work. 
 Personally I’m using ~400µF MKP with AKG K701 and have not experienced any lack of bass.
 As for output cap, I think that “quality” is ruling over “quantity” (with a reasonable value)._

 

Ferrari, I appreciate this info. I have been reading the websites you listed and it's certainly helping me remember things I once knew! 
	

	
	
		
		

		
		
	


	




 I am planning on driving Denon D5k (~25Ω) for now, and eventually Senn 650. I would like to get my hands on a couple Audyn-Cap MKP monsters like you posted at another place. If nothing else, just for the WOW effect! I am leaning towards using a pair of Solen MKP's (for each channel) @C5 to get to ~470uf and DynamiCaps @C1,C6. Although adding the Solen MKP's will meet the design specs, my biggest question is will the added expense significantly improve the SQ. I recall seeing a thread talking about that very subject, somewhere.... 

 When I was searching for the MKP's I ran across Electronic Concepts "Unlytic" capacitor. Does anyone have experience with this product?


----------



## V-DiV

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i'm not sure that there's any specific answers other than following the general rules about heater wiring and thermal management. in DIY, you have to suck it and see, and be prepared to be flexible to make layout/wiring changes if need be. 

 if mounting the PS FETs underneath, i would personally add a taller heatsink if you have the room - they get hot. i've posted my experiences dealing with heat and power dissipation with the multiplier mod i performed on my PS in this thread. i wouldn't be comfortable mounting the FETs to the chassis either.

 i also played around a bit with running multiple LEDs over a distance for some trick lighting effects. since the LEDs carry heater AC, they will carry noise as well. with no attenuation, source connected but no signal, heater noise was audible and changed in volume depending where i moved the LED wire. the least offensive was with the wire going straight up, perpendicular and away from the PCB. but heater noise was inaudible with attenuation at sane volume settings, so not an issue. i'm not suggesting that you don't air wire an LED or tubes, but rather to illustrate a point.

 i would do Amphead's Mod and add shielding to the air wired heaters if needed._

 

Thanks Fishski for the comments. Did you mean that you wouldn't mount the FETs to the chassis because air wiring would be bad with them because of noise, or that they shouldn't contact the chassis for safety, or something else? I would like to be able to build everything from the top plate, either mounted to the top or the bottom with boards upside down under the top plate. I don't really want the FETs (or are they MOSFETs) on top but they really shouldn't be upside down either. Will a larger heat sink do much good if upside down? They are the most puzzling part. Anybody have a good idea?

 I've been criss-crossing this thread and the Headwize thread too trying to gather up all the important bits and to decide on the last components. I've also been doing lots of internet hunting for components and supplies. My goody bag for the build is growing. I have Jeff's kit. I have jacks, etc., resistors for Regal's mod, and sockets for R2 and maybe some of the capacitors. I ordered some shielded and some non-shielded teflon wire from navships. I just now ordered a 270DAX and some ECC99s. I also just received a pair of 6DJ8s from The Tube Center in Orlando but the guy (Sam) sent me two different brands. 
	

	
	
		
		

		
		
	


	




 Next, I'm thinking about upgraded caps. I have a pair of Wimas for C6 but I'd rather do better (and put the Wimas in my Starving Student). Besides C5/C6, which caps will make the greatest improvement in the sound by replacing the electrolytics with film caps? I had been wondering about something like Balderon just mentioned, paralleling large film caps to come up to the necessary capacitance, but that's still quite expensive. But what would the effect be of paralleling one largish film cap (say~200uF) with a similar-size electrolytic. Would you get half the improvement, all the benefit of the film cap, no improvement, or worse? Ferrari, what do you think ?


----------



## fishski13

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Thanks Fishski for the comments. Did you mean that you wouldn't mount the FETs to the chassis because air wiring would be bad with them because of noise, or that they shouldn't contact the chassis for safety, or something else? I would like to be able to build everything from the top plate, either mounted to the top or the bottom with boards upside down under the top plate. I don't really want the FETs (or are they MOSFETs) on top but they really shouldn't be upside down either. Will a larger heat sink do much good if upside down? They are the most puzzling part. Anybody have a good idea?

 I've been criss-crossing this thread and the Headwize thread too trying to gather up all the important bits and to decide on the last components. I've also been doing lots of internet hunting for components and supplies. My goody bag for the build is growing. I have Jeff's kit. I have jacks, etc., resistors for Regal's mod, and sockets for R2 and maybe some of the capacitors. I ordered some shielded and some non-shielded teflon wire from navships. I just now ordered a 270DAX and some ECC99s. I also just received a pair of 6DJ8s from The Tube Center in Orlando but the guy (Sam) sent me two different brands. 
	

	
	
		
		

		
		
	


	




 Next, I'm thinking about upgraded caps. I have a pair of Wimas for C6 but I'd rather do better (and put the Wimas in my Starving Student). Besides C5/C6, which caps will make the greatest improvement in the sound by replacing the electrolytics with film caps? I had been wondering about something like Balderon just mentioned, paralleling large film caps to come up to the necessary capacitance, but that's still quite expensive. But what would the effect be of paralleling one largish film cap (say~200uF) with a similar-size electrolytic. Would you get half the improvement, all the benefit of the film cap, no improvement, or worse? Ferrari, what do you think ?_

 

maybe Alex could comment here, but looking at the PS voltage diagram, the Q1 and Q2 are passing >200V DC. i personally would want more than a sil pad between me and the mosfets.

 here's some larger heatsinks i used: Digi-Key - HS386-ND (Aavid Thermalloy - 531302B02500G)

 do you have a thermocouple probe on you DVM? vent holes would be a consideration as well.


----------



## Ferrari

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_
 Next, I'm thinking about upgraded caps. I have a pair of Wimas for C6 but I'd rather do better (and put the Wimas in my Starving Student). Besides C5/C6, which caps will make the greatest improvement in the sound by replacing the electrolytics with film caps? I had been wondering about something like Balderon just mentioned, paralleling large film caps to come up to the necessary capacitance, but that's still quite expensive. But what would the effect be of paralleling one largish film cap (say~200uF) with a similar-size electrolytic. Would you get half the improvement, all the benefit of the film cap, no improvement, or worse? Ferrari, what do you think ?_

 

Thinking of upgrading by replacing the electrolytics with film caps… besides C5 and C6, C1 can eventually replaced by a MKP film cap (what I did on mine). Actually, I’m using MKP film caps for C1 and C5, while C6 is omitted.

 About (how much) the sound improvement (will be) as a result of bypassing electrolytics cap with MKP film cap, there is no objective answer for that due to the unpredicted interactions between the 2 type of caps, using different dielectrics. However one thing is sure, the ESR of the output cap totally (electrolytics cap // MKP film cap) wil be improved.


----------



## V-DiV

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_maybe Alex could comment here, but looking at the PS voltage diagram, the Q1 and Q2 are passing >200V DC. i personally would want more than a sil pad between me and the mosfets.

 here's some larger heatsinks i used: Digi-Key - HS386-ND (Aavid Thermalloy - 531302B02500G)

 do you have a thermocouple probe on you DVM? vent holes would be a consideration as well._

 


 Fishski thanks. So it's not a good idea to mount to the case. I didn't really want to mount them on top anyway. I just was trying to mount them upright so the heat sinks would work right. I wonder if overly long heat sinks will work ok with the boards upside down. It doesn't seem like they would do the trick since the heat coming off the sinks would mostly rise back up to the board. I will definitely do some venting once I decide on the case design.

 I don't have a thermocouple probe. I've thought about them but haven't looked into it yet. Do they work for any DVM or just one made for them?


----------



## V-DiV

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Thinking of upgrading by replacing the electrolytics with film caps… besides C5 and C6, C1 can eventually replaced by a MKP film cap (what I did on mine). Actually, I’m using MKP film caps for C1 and C5, while C6 is omitted.

 About (how much) the sound improvement (will be) as a result of bypassing electrolytics cap with MKP film cap, there is no objective answer for that due to the unpredicted interactions between the 2 type of caps, using different dielectrics. However one thing is sure, the ESR of the output cap totally (electrolytics cap // MKP film cap) wil be improved._

 

Thanks Ferrari. I'll shop for some caps for C1. Interesting if this idea of mixing like-size electrolytic and film hasn't either been tried or is already known to be a bad idea from first principles of electronics.


----------



## Ferrari

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Interesting if this idea of mixing like-size electrolytic and film hasn't either been tried or is already known to be a bad idea from first principles of electronics._

 

Of course it (mixing electrolytic and film caps) has been tried out by engineers and designers for ages.
 But as I mentioned earlier -when different type of caps, using different dielectrics are putting in parallel- many parameters of the “new formed cap” will change (comparing to the independent caps). However, the changes can impact the characters of the “new formed cap” in both positive- and negative way, case by case. Therefore, an uniform, scientific founded conclusion can not be drawn.

 Also, notice that _“sound”_ is a very subjective matter, especially when it comes to the _“sound of caps”_.
 For some… it can sound like heaven (eureka, eargasm…), but for others… it’s totally craps.
 You might try and see if you like it (or not), simply trials and errors!


----------



## V-DiV

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Of course it (mixing electrolytic and film caps) has been tried out by engineers and designers for ages.
 But as I mentioned earlier -when different type of caps, using different dielectrics are putting in parallel- many parameters of the “new formed cap” will change (comparing to the independent caps). However, the changes can impact the characters of the “new formed cap” in both positive- and negative way, case by case. Therefore, an uniform, scientific founded conclusion can not be drawn.

 Also, notice that “sound” is a very subjective matter, especially when it comes to the “sound of caps”.
 For some… it can sound like heaven (eureka, eargasm…), but for others… it’s totally craps.
 You might try and see if you like it (or not), simply trials and errors!_

 

Thanks for the clarification. So it's known to be a gamble. In that case I will spend my money where it will definitely have positive effect such as really nice caps for C1 and C6. Suggestions?

 Pabbi, do you still have extra Rubicons. I'm interested in trying a pair for C5.


----------



## fishski13

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Fishski thanks. So it's not a good idea to mount to the case. I didn't really want to mount them on top anyway. I just was trying to mount them upright so the heat sinks would work right. I wonder if overly long heat sinks will work ok with the boards upside down. It doesn't seem like they would do the trick since the heat coming off the sinks would mostly rise back up to the board. I will definitely do some venting once I decide on the case design.

 I don't have a thermocouple probe. I've thought about them but haven't looked into it yet. Do they work for any DVM or just one made for them?_

 

if your DVM doesn't have a thermometer function, you would need to buy a thermometer or a DVM that has this function. i wouldn't worry about it too much. just add some vent holes beneath and above the boards with the larger heatsinks.


----------



## pabbi1

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Pabbi, do you still have extra Rubicons. I'm interested in trying a pair for C5._

 

 Yeah, down to my last 100 or so... 
	

	
	
		
		

		
		
	


	




 I really like the Obbligatos on c6. There are fancier options if you are so inclined.


----------



## adamus

I too like obbligatos on c6 - good value caps.


----------



## V-DiV

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Yeah, down to my last 100 or so... 
	

	
	
		
		

		
			





 I really like the Obbligatos on c6. There are fancier options if you are so inclined. 
	

	
	
		
		

		
		
	


	


_

 

Thanks Pabbi and Adamus. I'm not that fancy, so Obbligatos will probably be just fine. Pabbi, I sent you a PM.

 I just realized that I can procrastinate some more on making decisions on the casing: I still need to find, well I don't really have to at the moment, but I will anyway - I still need to put in a bit more into looking for an attenuator of some sort. In the little looking that I have done I haven't seen anything that struck me as an easy choice, good bang for the buck.


----------



## whitelabrat

So I've been able to do most of the board stuffing over the weekend, but I'm trying to decide my next move. I'd like to keep as close to the stock schematic as possible. Tubes will be PCC88, 6n6pi, EZ80 at least for now. I'm a bit stuck with the big 470uF capacitors. I was hoping to use TIP50's with 47uF caps, but for the sake of simplicity I don't think I'll go down that road yet. So I'm wondering. Why 470uF? That's pretty darn big. Any reason I can't use 120uF's instead? I've already got em and it would save me some $$. I've also got a 600uF 500vdc metallized polypropylene that I could perhaps use at C1, but I'm concerned the big value may cause issues. That and it's huge!

 Photos to come.


----------



## Ferrari

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_...I'm a bit stuck with the big 470uF capacitors. I was hoping to use TIP50's with 47uF caps, but for the sake of simplicity I don't think I'll go down that road yet. *So I'm wondering. Why 470uF? That's pretty darn big. Any reason I can't use 120uF's instead?* I've already got em and it would save me some $$. I've also got a 600uF 500vdc metallized polypropylene that I could perhaps use at C1, but I'm concerned the big value may cause issues. That and it's huge!

 Photos to come._

 

HINT.


----------



## whitelabrat

My fault. I should be more precise. I'd like to use 120uF capacitors for the power supply caps at C1, C4, and C5. I could potentially use a 600uF 500v metallized polypropylene for power supply cap C1. I'm also thinking that attaching a 1uF metallized polypropylene in parallel with the 120uF should help smooth any ripple. What benefit is there from the 470uF's in the power supply aside from bigger is better?

 I do intend to use at least 100uF metallized polypropylene output coupling capacitors at C5 and to do without C6 altogether.. I'll be using at least 100ohm headphones.


----------



## runeight

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_My fault. I should be more precise. I'd like to use 120uF capacitors for the power supply caps at C1, C4, and C5. I could potentially use a 600uF 500v metallized polypropylene for power supply cap C1. I'm also thinking that attaching a 1uF metallized polypropylene in parallel with the 120uF should help smooth any ripple. What benefit is there from the 470uF's in the power supply aside from bigger is better?

 I do intend to use at least 100uF metallized polypropylene output coupling capacitors at C5 and to do without C6 altogether.. I'll be using at least 100ohm headphones._

 

The 470u caps are sized to reduce the ripple to a neglibile amount. You may have a fair amount of ripple from the PS if you only use 120u.

 In addition the 470u at the output flattens the frequency response of the regulator so that it responds equally well over a wide frequency range.

 You may get away with 120u but the 470u are there for a reason.

 Otherwise, good luck on the build. It's good to have a few more folks trying this amp out.


----------



## pabbi1

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Thanks Pabbi and Adamus. I'm not that fancy, so Obbligatos will probably be just fine. Pabbi, I sent you a PM.

 I just realized that I can procrastinate some more on making decisions on the casing: I still need to find, well I don't really have to at the moment, but I will anyway - I still need to put in a bit more into looking for an attenuator of some sort. In the little looking that I have done I haven't seen anything that struck me as an easy choice, good bang for the buck._

 

Missed the PM, might resend... many other builders like the TKD2511 (regular taper, not the tkd2508 that I have), but the ebay guys are hit and miss, especially on the smd flavors. The surest shot is Goldpoint or DACT, both of which I am a fan, and prefer on the pricier builds.


----------



## amphead

Nice to see so many busy builders. Well I have mounted both L/R volume knobs on the front panel, through the precision bearings. They turn extremely smoothly, with a nice weight. I have polished the front panel to a near mirror shine, going from 2000 carbide paper, to Dico WR1 compound, and finally to Dico jeweler's rouge JR1. I wasn't sure that I wanted the super lustre, but now I like it. Pics of the progress coming soon.


----------



## whitelabrat

I ran some simulations using PSU Designer II and dang it! I learned something new today. I think I'll go with some variation that will include the 470uF caps in the power supply. Allied Electronics had some very nice pricing on some caps so I ordered a few, along with a 10H 270ohm choke. Perhaps overkill, but that's the spirit right! Don't laugh at my photos. I know the 1w 300ohm resistors are ridiculous. Its the only ones I could get along with all the other bits I wanted from a single source.

 I need to think enclosure now.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Nice to see so many busy builders. Well I have mounted both L/R volume knobs on the front panel, through the precision bearings. They turn extremely smoothly, with a nice weight. I have polished the front panel to a near mirror shine, going from 2000 carbide paper, to Dico WR1 compound, and finally to Dico jeweler's rouge JR1. I wasn't sure that I wanted the super lustre, but now I like it. Pics of the progress coming soon._

 

ooolala. can't wait to see some pics. i'm taking notes on your polishing protocol. 

 i have to finish the chassis for a Mini3 + passive line stage for a friend before i can tackle the Bijou re-chassis. drawings/layout are finalized. i've spent hours honing my routering skills and cutting aluminum with reasonable accuracy. clamps are your friends, hot kerf aluminum shavings are not.


----------



## balderon

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_BTW, I still have PLENTY of those caps for Bijou builders... do not pay the ebay price. Search the thread for details. Basically, I will send you a cap for every $1 donated to Head-fi, and I pay shipping._

 

It wouldn't hurt to give the Rubycon's a listen when that time comes. I have sent you a PM.


----------



## amphead

Here's a pic with polishing at about 80% on the front panel, and 90% on the volume knobs. The precision bearing is visible on the right hand side mounted into the front panel. More polishing tonight............


----------



## V-DiV

Amphead, your Bijou (gem) is going to be very lustrous!


----------



## balderon

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Here's a pic with polishing at about 80% on the front panel, and 90% on the volume knobs. The precision bearing is visible on the right hand side mounted into the front panel. More polishing tonight............_

 

Your missing a valuable accessory for your chassis. I did not see any holders for the white gloves needed as protection for greasy fingerprints! 
	

	
	
		
		

		
		
	


	




 Very nice work amphead!


----------



## runeight

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_Your missing a valuable accessory for your chassis. I did not see any holders for the white gloves needed as protection for greasy fingerprints! 
	

	
	
		
		

		
		
	


	




 Very nice work amphead!_

 

I was thinking the same thing. Won't he be afraid to touch it?


----------



## amphead

Thanks for the comments! 
 Still in the process of polishing the front plate. I am currently in the process of hunting down/purchasing a heavy duty mill-drill. The idea has occurred to me that some really interesting/beautiful amp chassis's can be created with one, as well as a multitude of volume knobs in different sizes. I used to own an entry level mill-drill years ago, but had to sell it because of a long-distance move. For now back to using the bench-top craftsman drill press for polishing..........


----------



## V-DiV

I know that caps rated 200 V are ok for C6. Are 200 V caps also ok for C1? I was considering Sonicraft Gen 1 for these positions on the amp board based on dsavitsk's review. Thanks.


----------



## Ferrari

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_I know that caps rated 200 V are ok for C6. Are 200 V caps also ok for C1? I was considering Sonicraft Gen 1 for these positions on the amp board based on dsavitsk's review. Thanks._

 

Yes, capacitor rated at 200V should be sufficient for C1 of the Bijou amp.


----------



## adamus

Messing around with my bijou today. I thought it was sounding slightly thin - just lacking the warmth it once had. I thought maybe its just my mind playing tricks on me since i have been listening a lot to my speaker amp (nice and warm el84 diy job). 

 took all measurements, they are all fine. Look at the heater voltage, and its 5.8v. A tad low. Turns out my dropping resistor (wirewound) must have changed slightly since i first put it in. quick replacement with a higher power version and i am back at 6.3v. 

 Oddly, the warmth and silky bijou sound it back. Reading around, slightly low heater voltage shouldnt really affect the sound much at all. MY little findings say otherwise.


----------



## runeight

Reducing the heater voltage by that much would have an effect on the sound. The cathode emiissivity will go down causing the bias conditions to change and less plate current to flow. So I think your unintended experiment is accurate. And this is also why Regal's mod imroves the SQ because it puts more current into the front end and phase splitter.


----------



## adamus

been playing some more, clipping dropping resistors in and out of the heater supplies. 

 results

 5.8v: thin sound, lacking warmth and low bass. 
 6v : getting better, analytical but the bass is there.
 6.3v: now were talking, the mids are full and lush
 6.6v: lush mids with deep deep bass. 

 So, given i am using cheap russian tubes (6n6p and 6n1p) and have a healthy stock of ez81, i am going to leave it at 6.6v. 

 The difference is not that subtle!


----------



## fishski13

Morgan Jones recommends aging wire-wound resistors in an oven at it's lowest setting for 24 hrs as their resistance is related to the tension on the wind.


----------



## adamus

I will admit, the change in resistance did take me by suprise, looks like morgan is right again.


----------



## amphead

Congrats Adamus, for helping to further characterize the tweaks we all need to get the most out of our builds. Maybe Runeight can put something like the Adamus mod on his web-site for heater current optimization.

 Currently I'm finding/trying the proper teflon washers with the right thickness for the best/tightest fit so that the knobs move smoothly but without any ability to move from 0 degrees in the axial plane(no wiggle room).

 Edit: I have an interesting design for the backlit badge/logo that won't require a large opening in the front panel. I'll leave it for your imagination until I do the prototype.


----------



## V-DiV

I got a surprise in the mail: 4 Rubycons! Thanks Pabbi. I'm sure you'll have a great time at the meet today. Looking forward to comparisons of Bijou with B22, etc.

 Most of my parts have arrived. A few more are on the way. Some decisions still to make. I may do some soldering this weekend just to feel like I'm under way.


----------



## adamus

just reflecting on my heater voltage experiement. 

 Its amazing how much difference to listening pleasure such a small change can make. been listening for 3 hrs now, the bijou is making beautiful music again.


----------



## balderon

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_Morgan Jones recommends aging wire-wound resistors in an oven at it's lowest setting for 24 hrs as their resistance is related to the tension on the wind._

 

To temper mine I think i will place the w-w resistors in the sun for a couple of days. I never thought the desert southwest weather would benefit a DIY project! 
	

	
	
		
		

		
			





 I wanted to start my chassis layout. The boards have not arrived and I have been unable to find the dimensions of the amplifier and power supply boards. Does anyone have the approximate sizes? TIA


----------



## wiatrob

The Bijou Headphone AmplifierI believe the Drill Template PDF's on the Cavalli audio website should be 1:1...


----------



## fishski13

pabbi1,
 how was the meet? didga bring yer BB?


----------



## pabbi1

Yes, I did. The beta22 was a no show, but the folks who's opinions I trust most were nonplussed. Oh, and I was trounced thoroughly by a TTVJ 307a.

 Not even close. Maybe I do need the Regal mods and some bigger c6 caps after all... tech problems with the BH mayhaps make me a bit pessimistic this evening - but, tomorrow is another day.


----------



## amphead

Ok, so a bit of a set-back on my build. I used some quality precision bearings available from my premium hardware store which happened to be .472" inside diameter. So instead of stainless shafts, I went with aluminum shafts and rotated/sanded them at the point of contact to fit the bearings. Even with teflon washers, there was 1mm of wobble. So on monday it's off to Grainger to get some 1/2" ID precision bearings and back to using the 1/2" stainless shaft. That should make no more than a .001"~.003" movement in the radial axis. Good enough for a build without a millling machine. I'm still looking for the right milling machine solution.


----------



## wiatrob

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_... Oh, and I was trounced thoroughly by a TTVJ 307a.
*SNIP...*
 tech problems with the BH mayhaps make me a bit pessimistic this evening - but, tomorrow is another day._

 


_You _were trounced or the SQ of the gear 
	

	
	
		
		

		
			





 Interested to hear what thoughts the morning brings. I've been lurking here as I am thinking about a high voltage build, and the Bijou is the logical choice. Not to mention that $~6k for the 307a isn't an option for me...


----------



## balderon

Quote:


  Originally Posted by *wiatrob* /img/forum/go_quote.gif 
_The Bijou Headphone AmplifierI believe the Drill Template PDF's on the Cavalli audio website should be 1:1..._

 

Thanks @wiatrob for your help. I need to remind myself to think outside the box!


----------



## wiatrob

If anyone needs any Obligatos, let me know, I am putting in an order for a possible bijou build and for some others...

 Pabbi, I might take you up on the donation/cap deal...

 EDIT: I should clarify - I'm planning to order a bunch from diy_hifi_Supply a(1uF adn also some .22uFs for my Soha II) and wanted to know if anyone wanted some to save on combined shipping. I'll see if we can get a deal, PM me if you're interested.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Yes, I did. The beta22 was a no show, but the folks who's opinions I trust most were nonplussed. Oh, and I was trounced thoroughly by a TTVJ 307a.

 Not even close. Maybe I do need the Regal mods and some bigger c6 caps after all... tech problems with the BH mayhaps make me a bit pessimistic this evening - but, tomorrow is another day._

 

DIY...it's swings and roundabouts.

 i wouldn't give up yet. Regal's mod is an easy and cheap punt. why not try experimenting with signal hook-up wiring as well? i have yet to replace the SPC signal wire in my Bijou with silver/cotton from Partsconnexion ($2/ft), but the ICs i made with this wire a la Chris VenHaus's silver IC recipe at vhaudio.com is a clear winner in every aspect from from any other i've attempted, including AntiCables. not subtle by any means.

 film output caps for balanced would get pretty pricey, much less so if driving higher impedance Senns. i'm going to order some 220uF Mundorfs this week. i'm also contemplating redoing the amp boards P2P for the Bijou re-chassis.


----------



## pabbi1

Ok, reflection returns - Regal mod may make it happier, but what can tighten up the bass? I'm using 1uF Obbligatos on c6 - would 6.8uF make a big difference on the bass? Just a tad flabby, but maybe that is not always such a bad thing.


----------



## luvdunhill

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Ok, reflection returns - Regal mod may make it happier, but what can tighten up the bass? I'm using 1uF Obbligatos on c6 - would 6.8uF make a big difference on the bass? Just a tad flabby, but maybe that is not always such a bad thing._

 

not likely. If you're willing to optimize the amp for a certain impedance, then you could try and stick a film in for C5. Mundorf M-Cap comes to mind as a possibility. Maybe try a Solen first before shelling out the cash for the Mundorf. Also, you could try something other than the Obbligato for bypass... perhaps Russian teflons...

 Alex: do you think there would be any performance gain by using LEDs for D1-D6?


----------



## pabbi1

That is funny - I got a Mundorf 47uF MCap in the mail today - just need to find three more. Or, not.

 To compare the Bijou to a transformer coupled amp really was not fair, and it still sounds good, no matter what my friends say.


----------



## luvdunhill

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_That is funny - I got a Mundorf 47uF MCap in the mail today - just need to find three more.:_

 

or 39 more


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Ok, reflection returns - Regal mod may make it happier, but what can tighten up the bass? I'm using 1uF Obbligatos on c6 - would 6.8uF make a big difference on the bass? Just a tad flabby, but maybe that is not always such a bad thing._

 

i am a former aspiring classical double-bass player. the first sonic trait i evaluate with hi-fi is the bass. i am picky and hate any form of flabby thump. i like it supple, clean and detailed - i hate a dry chalky or hard sound. it's a fine line to balance. 

 with my balanced Bijou, as i mentioned before, the bass was too much w/HD650 for my tastes. this worked well with the K701, mitigating the chalkyness and adding a bit more "suppleness" and mid-bass bounce without ever being too overbearing. 

 the greatest strength of balanced was the surreal headstage. a visual analogy would be like watching a film at a domed OmniTheater or a 3D Imax. also guitars, strings, and skins sounded super spectacular. balanced = everything sounded much bigger. what do you think?

 i won't swear on my dead golden retiever's urn, but balanced sounded so effortless that i think that SE may have an edge in apparent dynamics. this perceived difference could be explained by the fact that the balanced presentation forces you to focus your attention elsewhere. 

 if i hadn't blown half my amp, i'd still be happily plugging away and tweaking for the sole purpose of listening to the K701. i was also considering wiring only half of the balanced amp for the HD650 only.

 tiddying up the bass:

 i have no input on caps, or any other amp-proper changes, but believe wiring to be extremely important - especially with regards to tweaking particular frequencies and overall detail retrieval. 

 1. as i said before, i would consider the silver/cotton for signal hook-up. much better than the SPC from Navships, Mogami, and Oyaide PA-02 i've tried in the Bijou. i don't hear any of the stereotypical negatives often associated with silver in this application, as long as you don't mind a more focused, detailed bass response. try some ICs with decent RCAs as well.

 2. the Flavor2 is a cheap PC to build from vhaudio.com: DIY Power Cord. it has a very authoritative, fast, and punchy bass. sounds great on my Krell amp into ATC speaker combo too. buy the supplies from Chris. i didn't use the hose with either of my Flavor2 PCs. his wire is uber nice and Chris offers superb customer service.

 3. i doubt you want to dick around with your TKDs, but i found the shunted nude Vishay TX2352 to be more detailed and less grainy throughout the frequency spectrum, including the bass, than either the RN60 or Kiwame. 

 4. buy a pair of K701
	

	
	
		
		

		
		
	


	




. 

 what did you lick so much about Pete's amp?


----------



## pabbi1

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_what did you lick so much about Pete's amp?_

 

Everything - mainly how tight the bass was - as a bass player myself, that was what really clenched it for me. I do love me some balanced Bijou soundstage, but... and, better balance. Nay, IMPECCABLE balance.


----------



## amphead

It's amazing how so many musicians get involved with the DIY amplifier builds, myself included. Played electric guitar since I was 16.

 Well, I have used JB Weld (Kwik) to attach a stainless shaft to one of the knobs, after removing both of the off size bearings. Tomorrow, I will attach one of the .5" bearings that I purchased at Grainger.


----------



## fishski13

i ordered a couple of 150 uF M-caps for C5. we'll see if the K701 craps out or not. hoping the HD650 sounds even better.

 working on drawings for P2P layout as well.


----------



## V-DiV

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i am a former aspiring classical double-bass player. the first sonic trait i evaluate with hi-fi is the bass._

 

 Quote:


  Originally Posted by *pabbi1* 
_as a bass player myself_

 

 Quote:


  Originally Posted by *amphead* 
_It's amazing how so many musicians get involved with the DIY amplifier builds, myself included. Played electric guitar since I was 16._

 

The bass players seem to be in the majority here. I am also a former bass player, etc. I don't have anyone to play with anymore. My 5th grade son is going to be a good guitarist. I'm trying to get my fourth grader interested in drums, ideally, or bass. Then I'll take what's left (or we'll find some other kid to play drums) and we'll have our own combo.

 Waiting on my transformer to arrive from RadioDaze. Hope to get my build moving along before work gets too busy. As it is I've been spending a lot of my "free time" shoveling snow.

 I'm interested to hear what direction you will take next Pabbi. I'm going to build mine with Regal's mod to begin with. After the initial build, I will do the mod to use 6H30s. Also interested to hear how the 150 uF caps go Fishski.


----------



## amphead

Well, I have mixed results with JB Weld(Kwik). My shafts are mounted solidly with it, but the material became gummy and weak, when trying to use it on the bearings. No worries, I removed it and will use tried and true 2 ton epoxy for the job.


----------



## TimmyMac

Today, I got 4 small presents from pabbi! They'll be installed soon... report to come... hopefully I'll get my PCM1794 DAC up and running soon so I can give real impressions.


----------



## amphead

Good job guys! Work in progress.


----------



## balderon

I have about 6 LED's to illuminate. I did not want to add an additional supply so I was thinking of siphoning about 10ma (~2W) from the B+ supply. My supply will be using a Hammond 370, EZ81, and the Regal's Mod. Can anyone think of a reason why this would be a bad idea?

 I am mounting my EZ81 on top of the chassis and I had a difficult time finding a male connector for a standard 9-pin tube socket. I finally found something that should work very well at Apex Electronics! The existing wires are too small to use to for the tubes but the shield of the plug screws off. You can remove the existing wires and solder on larger wires onto the top of the solid pins. The mechanical connection to the pins is not the greatest but its the best I have been able to find.


----------



## Dantes

After a lot of listening time, i will go back the technical side of my Bijou.

 I will bye some obbligato caps and a new attenuator to replace the blue ALPS.

 There is good feedback on this one: http://cgi.ebay.com/ws/eBayISAPI.dll...m=270334964045

 I will rewire more cleanely my bijou. It's a mess in it and i'll replace some crapy wires and had some sheilded ones.


----------



## jamess71

Well after about 2 months of working on my Bijou, part time of course, a 2 yr. old and a 2 month old.  I'm finally wiring it up. Started doing P2P but the connectors on the boards are a bit small with the 18g wire I'm using so I'm going the terminal block route. 

 I'm thinking I might as well get it right the first time so what wires/connections should be shielded and also is 24ga navships wire good for signals without extra shielding?

 Basically looking to avoid future rewiring. Any good tips. I've read this whole thread along with headwize and I'm a bit overwhelmed with info. 
	

	
	
		
		

		
		
	


	




 I'll try and get a few pics up tonight. So close I can taste it.


----------



## V-DiV

Quote:


  Originally Posted by *Dantes* /img/forum/go_quote.gif 
_After a lot of listening time, i will go back the technical side of my Bijou.

 I will bye some obbligato caps and a new attenuator to replace the blue ALPS.

 There is good feedback on this one: DACT Type 23 Stepped Attenuator Potentiometer 10K 300b - eBay (item 270334964045 end time Feb-23-09 10:11:33 PST)
 ._

 

Hey Dantes, If you try that attenuator let us know your impression of how it sounds compared to the blue ALPS. I presume you know, but just in case you don't, that is not an actual DACT attenuator. They refer to it as a "DACT type." There was some comment on it some time in the past year, perhaps you saw it. I don't remember what the conclusion was.


----------



## amphead

From what I could hear on Pabbi's amp. The discreet resistors in the attenuator he had, blew the doors off of the Alps pots. Warmer slightly and much more detailed.


----------



## Dantes

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Hey Dantes, If you try that attenuator let us know your impression of how it sounds compared to the blue ALPS. I presume you know, but just in case you don't, that is not an actual DACT attenuator. They refer to it as a "DACT type." There was some comment on it some time in the past year, perhaps you saw it. I don't remember what the conclusion was._

 

Yes i know.
 The original DACT is a lot more expensive. 
 I read some review and this atenuator is a lot better than an alps and cheap.
 I will tell my fealings about it when i receive it


----------



## Dantes

In my reading again of this thread (take a LOOOOOT of time 
	

	
	
		
		

		
		
	


	




), i read that 6N1P could replace the 6DJ8/ecc88 tubes.

 All ecc88/6DJ8 i bought are noisy or not good and i can't afford 100$ on a good NOS pair. My wife will kill me... and my banker too... 

 I saw there is many versions of the 6N1P: vi, ev and EB.
 Which one is the best option ?
 I found a lot of all on ebay at all prices. Incredible.


----------



## Ferrari

There are indeed several variants of Russians 6N1P-xx for sale on eBay.
 I have used tubes labeled: 6Н1П-ВИ and 6Н1П-ЕВ (6N1P-VI and 6N1P-EV respectively) with good results. 
	

	
	
		
		

		
		
	


	




 I have also tried tubes labeled 6Н1П (without 2 additional letters, '90 made), but it was a real disappointment. 
 This tube variant has single getter supporter (instead of double getter supporters of the 6N1P-VI and 6N1P-EV).

 Don’t forget to modify R2 on the amp board accordingly when you roll 6N1P-xx tubes in.


----------



## bhjazz

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I have about 6 LED's to illuminate. I did not want to add an additional supply so I was thinking of siphoning about 10ma (~2W) from the B+ supply._

 

I'm going to keep an eye on the responses for this. My only concern would be if any noise would return back into the powe supply circuit. I don't know if that would be filtered by any resistors for the LEDs. 



  Quote:


  Originally Posted by *jamess71* /img/forum/go_quote.gif 
_Well after about 2 months of working on my Bijou, part time of course, a 2 yr. old and a 2 month old.  

 So close I can taste it. 
	

	
	
		
		

		
		
	


	


_

 

Wow. I hear you on the part-time thing. No kids here, but I moved at the end of last year and still have lots to do. I think lately this qualifies as no-time....
	

	
	
		
		

		
		
	


	




 I'm sure the Bijou folks think I'm just a poser...always posting...never building..haha....

 So you're close. Good. Don't rush! That is the part of the build where I start to mess things up just to get it running. Don't do it!!! Good luck!


----------



## Ferrari

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_... I'm sure the Bijou folks think I'm just a poser...always posting...never building..._

 

You have just read my mind!


----------



## Dantes

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Don’t forget to modify R2 on the amp board accordingly when you roll 6N1P-xx tubes in. 
	

	
	
		
		

		
		
	


	


_

 

ho yes... didn't think at that... 

 I'have done the regal mod.
 So, R2 value have to change anyway ?


----------



## runeight

Dantes, these values for some tubes are on the Bijou website under the Regal mod.


----------



## Dantes

ho my... i had miss them...
 sorry and thanks


----------



## bhjazz

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_You have just read my mind!_

 

Then you've read the last of my "gee, that looks awsome" posts....


----------



## Ferrari

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_Then you've read the last of my "gee, that looks awsome" posts...._

 

Eehe... hope that you don’t take it too seriously. It’s mentioned as a little “teasing in a friendly manner” (if you know me). 
	

	
	
		
		

		
		
	


	



 Speaking about lacking of time… several of my DIY projects are delayed because of that.


----------



## amphead

We look forward to seeing these builds. 

 I have finally finished mounting the knobs into the new .5" bearings and 1/2" stainless shafts into the front panel. Using 2 ton epoxy turned out to be the best solution. There is stronger epoxy out there, however I'm not going to spend any more time on that. The volume knobs move smooth as butter and are very rigid within their rotational axis. I have to re-polish everything on the front panel and then I can start building the amp single ended until I have all of the parts for balanced configuration.


----------



## V-DiV

I have lots of parts but no case solution yet. I'm trying on an old Pioneer tuner for size. It is 9" X 16". I would have to mount the transformer to the side rail because the case is not tall enough. I will also have to stiffen the bottom and back and do something clever with the front. What do you think?


----------



## fishski13

i hope you have decent homeowners insurance 
	

	
	
		
		

		
		
	


	




.


----------



## V-DiV

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i hope you have decent homeowners insurance 
	

	
	
		
		

		
		
	


	




._

 

That hot huh? I was actually planning to get some steel to replace the particle board bottom and back if I decided to use this. My biggest concern is that I wouldn't have enough separation to avoid the hum woes. The other issue is that I might spend so much time and money on this scrounged up case that I might as well spend a chunk of money for a good commercial case to begin with. The HiFi2000 cases look quite nice but I imagine they would be overly pricey including shipping. Probably best to go back to the wood frame idea like TimmyMac and BottleHead but I'll have to source a good top and bottom plates and make some ventilation. The vented steel top is the best thing about the Pioneer case. I don't want to make a silly pattern of drilled holes. I don't find that too appealing a look.


----------



## bhjazz

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Eehe... hope that you don’t take it too seriously. It’s mentioned as a little “teasing in a friendly manner” (if you know me). 
	

	
	
		
		

		
		
	


	



 Speaking about lacking of time… several of my DIY projects are delayed because of that._

 

You didn't see the tongue? Ha! No, I didn't take it seriously at all, and I _do_ know you. But it did get me to thinking about what I've done in the last year: CKKIII, Alien DAC, Dynahi rebuild, and turntable gut and rebuild, bought a house. Guess I had more time than I thought. Still, though..._I want more._ 
 And back to the Bijou: I am solidifying my case design, made a few sketches, done lots of googling. I think the outward look of the unit will take me longer than the build. And I'll leave that as a tease.


----------



## amphead

Finished polishing the front panel and volume knobs. How are the other builds progressing?

 Edit: would like to buy this milling machine...........
http://www.kdcapital.com/Products/Pr...oductID/473982


----------



## V-DiV

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Finished polishing the front panel and volume knobs. How are the other builds progressing?_

 

I'm still exploring avenues for casing. I thought about saving money by scrounging something, but haven't found anything appropriate and nice. I thought about spending money on something pre-made but haven't found anything I like. So it looks like I'll go back to the original plan of a wood frame with metal plates top and bottom. Where do you buy appropriate gauge aluminum sheets (and then some thinner stainless or copper for shielding)?


----------



## MoodySteve

I'm thinking along these lines for casing. The frame willl be around 1/2" wood painted, lacquered and polished. The top panel will be 1/8" aluminum, not sure about finish yet.

 Edit: V-Div, just noticed you're near NYC. Cool to find a fellow Bijou builder in the area!


----------



## holland

^ That's hot.


----------



## pabbi1

That is a very nice case... should that be too ambitious, there is the NABU. The plastic front panel is removeable, to be replaced with wood or metal. It is the case in my Millett Max link in the sig. Dirt cheap, and built like a tank.


----------



## V-DiV

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_I'm thinking along these lines for casing. The frame willl be around 1/2" wood painted, lacquered and polished. The top panel will be 1/8" aluminum, not sure about finish yet.

 Edit: V-Div, just noticed you're near NYC. Cool to find a fellow Bijou builder in the area!_

 

Hey MoodySteve, nice layout. Is that a graphical rendering or an actual amp? That is my basic idea too, although I was planning to have a polished aluminum top plate. The painted top looks good too. 

 Maybe we can compare our end results at an upcoming local meet.


----------



## MoodySteve

It is a graphical rendering done in a 3D CAD program.

 I'd love to compare the two amps, as I'll be using a slightly modified BOM and circuit (Regal mod, probably Amphead mod). Are you building it totally stock?


----------



## V-DiV

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_It is a graphical rendering done in a 3D CAD program.

 I'd love to compare the two amps, as I'll be using a slightly modified BOM and circuit (Regal mod, probably Amphead mod). Are you building it totally stock?_

 

Regal Mod, Amphead Mod, Rubycon for C5, Sonicaps for C1 & C6, attenuator for volume control, eventually the 6H30 mod.


----------



## Ferrari

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_I'm thinking along these lines for casing. The frame willl be around 1/2" wood painted, lacquered and polished. The top panel will be 1/8" aluminum, not sure about finish yet.

 Edit: V-Div, just noticed you're near NYC. Cool to find a fellow Bijou builder in the area!





_

 




 Impessive CAD work. If you are going to implement your Bijou along that line, it should be great. 
	

	
	
		
		

		
		
	


	



 I like the originality, something totally different than the kind of “uniform enclosure”, using by many builders (more or less) at the same time.


----------



## MoodySteve

V-DIV: That sounds fairly close to my own planned build, except that I am using Obligatto Gold 1uF for C6 and I'm probably not going to go high-end on the attenuator (I feel that if any piece of my gear deserves an attenuator upgrade, it would be the ß22). Of course, I will try to leave room for tweaking later on (I do have all the parts necessary to roll tubes). 

 Ferrari: Thanks for your kind words! I really do hope that the final product resembles that as closely as possible; I think the weak link will be my surface finishing skills, but I need to improve those anyway. Your incredibly attractive and clean builds have been serving as a reference for me since I started to build. Like you, I like my projects to look a little different.


----------



## pabbi1

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_V-DIV: That sounds fairly close to my own planned build, except that I am using Obligatto Gold 1uF for C6 and I'm probably not going to go high-end on the attenuator (I feel that if any piece of my gear deserves an attenuator upgrade, it would be the ß22). Of course, I will try to leave room for tweaking later on (I do have all the parts necessary to roll tubes)._

 

The Bijou needs a good attenuator every bit as much as a b22. The rk27 is simply not up to task, so even the eBay steppers would be the very least option for this amp, IMHO.


----------



## MoodySteve

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_The Bijou needs a good attenuator every bit as much as a b22. The rk27 is simply not up to task, so even the eBay steppers would be the very least option for this amp, IMHO._

 

I see what you mean - What I really meant was 'If I were to only buy one really good attenuator, I would put it in my ß22 rather than the Bijou.' No real reason other than the ß22 has been my pet project for the past year.

 I will probably experiment with attenuators further down the line just to see if it's worth the fuss to me. If it turns out I have tin ears that can't discern a difference between RK27 and a Goldpoint, I suppose I'll be sticking with the RK27.


----------



## amphead

While attenuators are certainly a step up, the RK27 are OK as place holders for the inevitable upgrade to attenuators. That way you can enjoy the machine a little earlier.  Edit: that will be my plan of attack.


----------



## V-DiV

I picked up some maple 1X4 at Home Depot for the frame and ordered aluminum sheeting from Online Metal for the top and bottom plates - more than I would have liked to spend but will save myself lots more time hunting. Next issue with the case is how to put the name, Bijou, on the front. I've done my share of woodworking, mostly rough stuff, but never did any lettering. Suggestions?


----------



## pabbi1

Well, there is a logo floating around somewhere...


----------



## TimmyMac

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_I picked up some maple 1X4 at Home Depot for the frame and ordered aluminum sheeting from Online Metal for the top and bottom plates - more than I would have liked to spend but will save myself lots more time hunting. Next issue with the case is how to put the name, Bijou, on the front. I've done my share of woodworking, mostly rough stuff, but never did any lettering. Suggestions?_

 

Buy a set of steel letter punches, heat them up with a torch, and burn the letters into the wood.

 works better for labeling volume and stuff, since the punches tend to have boring fonts.


----------



## V-DiV

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Well, there is a logo floating around somewhere... 
	

	
	
		
		

		
		
	


	


_

 

I recall that, but I don't remember seeing it implemented on anyone's amp. I wonder how I would do it on wood. Perhaps have some sort of medallion created?

  Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_Buy a set of steel letter punches, heat them up with a torch, and burn the letters into the wood.

 works better for labeling volume and stuff, since the punches tend to have boring fonts._

 

That's an interesting idea. Where do you get these, and are they expensive???

 Alternatively, I could buy a particular type of dremel and a router base for it and a set of lettering guides...that sounds like a lot of money.

 Or I could buy a set of wood-carving knives and spend a few months practicing. 
	

	
	
		
		

		
		
	


	




 Hey TimmyMac, I wanted to take a quick peak at your wood-framed Bijou but your pictures are gone. Are they still accessible someplace?


----------



## TimmyMac

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_That's an interesting idea. Where do you get these, and are they expensive???

 Alternatively, I could buy a particular type of dremel and a router base for it and a set of lettering guides...that sounds like a lot of money.

 Or I could buy a set of wood-carving knives and spend a few months practicing. 
	

	
	
		
		

		
		
	


	




 Hey TimmyMac, I wanted to take a quick peak at your wood-framed Bijou but your pictures are gone. Are they still accessible someplace?_

 

I got a set of 1/4" punches off e-bay, for around $20 shipped. If this guy shipped to Canada I'd probably buy this:
120 PC LETTER / NUMBER / HOLE PUNCH COMBO SET - eBay (item 350143693006 end time Feb-19-09 11:51:21 PST)

 Here are the pics of my bijou...


----------



## pabbi1

I have a jpg, but laser engravers prefer a line art version, as it is much crisper. I have the small wood for a plate, just waiting for Amphead to finish his build so he can then finish the line art... unless someone could take up the cause...


----------



## V-DiV

Quote:


  Originally Posted by *TimmyMac* /img/forum/go_quote.gif 
_I got a set of 1/4" punches off e-bay, for around $20 shipped. If this guy shipped to Canada I'd probably buy this:
120 PC LETTER / NUMBER / HOLE PUNCH COMBO SET - eBay (item 350143693006 end time Feb-19-09 11:51:21 PST)

 Here are the pics of my bijou..._

 

TimmyMac, thanks for the pictures. I remembered really liking the color of the stain that you used and how you countersunk the front panel elements. And thanks for the link to the punch set. It looks interesting.

 Pabbi, I would just be happy to be able to use just the name Bijou with the nice font that Amphead found or something similar, either as a commercially laser engraved medalion, or somehow doing it myself. I wasn't super excited by the gem drawing that was passed around last summer, but maybe I didn't see the last version. But it would be cool if we could have a common logo that all could use. I've been spending too much time on this lately, but it wouldn't take too much time to turn the jpeg into a line drawing.


----------



## amphead

Yeah, well there isn't an "official" logo for the amp per se. It could well be that there will be variants of what each builder wants for their amp design. This way, no controversy over what each amplifier gets. After all, Ferrari has already engraved the panel on his amplifier, and that would be his logo. I would help a couple builders to have the same badge/logo that I will create. No prob. It will be unique/backlit, and won't require a large cutout on the panel.


----------



## pabbi1

Oner picture worth a thousand words...


----------



## amphead

It's in the running for my backlit badge project. Just have to see a mock-up or prototype of the badge to be sure. I'll be working on that soon........


----------



## whitelabrat

I have to hang my head low. Apparently I wasn't entirely lucid when I bought the parts for the power supply. I left the 'K' off of R2, R9, and R6. The EZ80 was not at all happy. I could imaging having 250+ vdc on the heaters doesn't go over well. The EZ80 got bright red, but didn't fail. R7 and R8 started smoking, as well as R6 and R7 which have charr marks on them. 
	

	
	
		
		

		
			





 Ugh. I need new glasses. Thank goodness for my variac.

 I had a super overkill 30k metal oxide resistor that I put into R2, but I'll need to put in an order for the 348k's.

 I'll need to double check the amp boards to be sure I didn't do anything silly there too. 
	

	
	
		
		

		
		
	


	




 I've attached some poor quality photos courtesy of my blackberry.


----------



## V-DiV

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_I have to hang my head low. Apparently I wasn't entirely lucid when I bought the parts for the power supply. I left the 'K' off of R2, R9, and R6. The EZ80 was not at all happy. I could imaging having 250+ vdc on the heaters doesn't go over well. The EZ80 got bright red, but didn't fail. R7 and R8 started smoking, as well as R6 and R7 which have charr marks on them. 
	

	
	
		
		

		
		
	


	




 Ugh. I need new glasses. Thank goodness for my variac.

 I had a super overkill 30k metal oxide resistor that I put into R2, but I'll need to put in an order for the 348k's.

 I'll need to double check the amp boards to be sure I didn't do anything silly there too. 
	

	
	
		
		

		
		
	


	




 I've attached some poor quality photos courtesy of my blackberry._

 

Big bummer. I won't sneer, at least not until I start mine up without smoking something.
	

	
	
		
		

		
		
	


	



 I hope you didn't do too much damage. Good luck sorting it out.


----------



## Dantes

Today i received a pair of ecc99 to replace the 6n6p-i.
 I put them in my bijou and... the PS output drop at 234V without an head-phone plug into the amp.

 In fact, the output of the PS board varies between 245 and 234V wit my beyer pluged-in and the trimpot do nothing.

 I have tested again my PS board with a 100K resistor and it works fine, including the trimpot.

 I have done regal mod and have a 250-0-250 transformer.


 Some measure on the PS with all wired:
 R7:240V
 R8:288V
 pin 5 of the EZ81: 38V
 6,7V-AC on the heater.


 The amp works fine however but with a lake of bass but a mush clearer sound. 


 EDIT: After reading again some messages, i think, my mosfets are dead... crap -_-


----------



## amphead

If you can't get a stable reading of 250vdc from the power supply, that would be very likely. Sorry to hear about your misfortune guys.


----------



## fishski13

received my M-caps today, but unfortunately my Bijou re-chassis is on the back burner. i'm building a SOHA II, gamma-1, Gainclone, and some full-range Fonken speakers for a friend - plus....

 amphead,
 i have parts for the High Octane guitar amp i'm building for another friend arriving tomorrow. thanks for the recommendation - i can't wait to hear how it sounds. he's pretty stoked.


----------



## amphead

That's awesome man! I wish I had the time to put a guitar amp on the front burner, but for now at least it's my slooowww.... bijou build. I decided to spend time doing each step, to try and get it right the first time.


----------



## wiatrob

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_.... I left the 'K' off of R2, R9, and R6. The EZ80 was not at all happy. ...._

 

Blowing things up is a powerful means of learning! I should know... It's handy to meter every resistor, even if you order the right ones, there can always be a mix up... Good luck!


----------



## whitelabrat

Quote:


  Originally Posted by *wiatrob* /img/forum/go_quote.gif 
_Blowing things up is a powerful means of learning!_

 

That's right. Just as long as I don't blow me up. 
	

	
	
		
		

		
		
	


	




 I finished checking the amp board again, and sure enough a lot of resistors have a decimal in the wrong place. Man, I hate replacing bits. Geez.

 An interesting side note, there's a thread on another forum that goes into 6N6P-i vs 6N6P. It seems that the 6N6P-i may be the lesser of the two, but I'm not 100% convinced yet. The impulse version is designed to take more of a beating which may explain a rated life of 500hrs vs the 6N6P's 2000hrs.


----------



## Fast3d

Has anyone bought anything from this site? I like their cases.
Audio Catalog


----------



## amphead

A member by the Head-fi name Mazuki bought an R-core transformer from them. You could PM him, but I believe he had a positive experience. Good Luck!


----------



## dBel84

Quote:


  Originally Posted by *Fast3d* /img/forum/go_quote.gif 
_Has anyone bought anything from this site? I like their cases.
Audio Catalog_

 

Yes - I have used them a fair amount recently and they are very reliable. Great selection of quality DIY parts too ..dB


----------



## Fast3d

Thanks for replying I'll start ordering here soon for a case for my Bijou. Any other site with good cases?


----------



## adamus

agreeing with others - vt4c is a superb seller.


----------



## amphead

I was looking at some polished carbon fiber, for control plate material. Black, shiny, beautiful, and the 1/4" is astronomical in price. Very lightweight and strong. Would be nice to consider for a future project though. 2 week lead time however for custom W x L.


----------



## TimmyMac

You could always buy the cloth and lay it up yourself. It's fun, but a lot of work. And you'll need access to a decent router if you want anything like straight edges.

 I'm assuming it's just for cosmetic purposes? 1/4" plate is a bit beyond what carbon is normally used at unless it's cored


----------



## V-DiV

I'm making slow progress on my Bijou. Started soldering components. I've received aluminum for my top/bottom plate and have my maple waiting to build my case. But I need a couple of resistors before I can finish the boards and I don't want to get junky ones from Radio Shack or pay shipping for just two resistors. I am trying to think of everything I can put into a Mouser order. So I've decided to do the 6H30 mod in the initial build. I want to mount a switch on the back panel to select between AUX Trans on-off so I can either run 6DJ8/6922 tubes or 6H30. Huskydawg used a 1.2 A transformer, but Hammond also makes a 1 amp which I presume would be better (even if it is on backorder at Mouser). 

 Will this transformer be good: 
 Hammond 166J6, single primary, 6.3 volt C.T., 1 A

166J6

 Runeight, any problem with running 6H30 and 6N1P with Aux transformer and Regal's mod? I know when I have the Aux trans off I will need to run ECC99 and not 6N1P output tubes with Regal's mod. I will be using EZ81.

 Also, are there any wrinkles here with doing Amphead's mod?

 Thanks.


----------



## V-DiV

For mounting the mofsets, in addition to the insulating sheets shouldn't there also be bushings for the screws and teflon/plastic washers for the nuts to completely isolate the mofsets from the heatsinks? My Glass Jar kit didn't come with all of these goodies (actually, there was just one bushing and I guess that's what it's for).

 Thanks again,
 Vic


----------



## bhjazz

Quote:


  Originally Posted by *Fast3d* /img/forum/go_quote.gif 
_Has anyone bought anything from this site? I like their cases.
Audio Catalog_

 

I have as well. Good, dependable service and lots of interesting goodies.


----------



## TimmyMac

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_For mounting the mofsets, in addition to the insulating sheets shouldn't there also be bushings for the screws and teflon/plastic washers for the nuts to completely isolate the mofsets from the heatsinks? My Glass Jar kit didn't come with all of these goodies (actually, there was just one bushing and I guess that's what it's for).

 Thanks again,
 Vic_

 

The shoulder washers go in the MOSFETs to isolate the screw from the tab.


----------



## balderon

I have not posted for a while so why not post an update. I have made good progress on my Bijou casework. My design is finalized and I hope to complete the fabrication by mid March. All the parts are in and I'll heat up the soldering iron soon afterwards.


----------



## Dantes

I had change the 3 Wima MKP with 3 Obligaddo caps on one channel. 
 For now no differences... perraps it will apear after some hours of running.

 Next step, doing the same change on the other channel and change the attenuator.


----------



## amphead

Good to hear about your progress Balderon, Dantes!

 Well no post in here from me lately, as I was on the mend. Stressed myself out just working on the bling for the front panel, and aggravated/developed my peptic ulcer(sorry a little off-topic). I had to just stop and leave it alone while drinking aloe vera juice and taking prilosec. Feeling much better now.  Working on the Bijou Logo/Badge again. Edit: part of the Bijou badge involves work from a commercial stained glass artist, but no it isn't stained glass. He was having trouble achieving what I needed to have done and I cancelled the initial work and started in a new direction.


----------



## amphead

The logo involves a bit of aluminum cutting that would be better done with a small milling machine, but I haven't found the right one yet. I looked at a place locally called Scott Machinery in Sacramento, but his prices are a bit on the high side, especially considering the economy. Should have the badge done in a few more days, then pics.


----------



## Dantes

* wait for the pics * 
	

	
	
		
		

		
			





 I had change the caps and obligaddo works fine 
	

	
	
		
		

		
		
	


	




 And the PS too... I do not change anything exept caps ans now with the ECC99 i have 250V without problem.

 For me ECC99 with regal's mod is better than others configurations for this stage of the amp. The sound is clearer and have better dynamic.


----------



## Dantes

* wait for the pics * 
	

	
	
		
		

		
		
	


	




 I had change the caps and obligaddo works fine 
	

	
	
		
		

		
		
	


	




 And the PS too... I do not change anything exept caps ans now with the ECC99 i have 250V without problem.

 For me ECC99 with regal's mod is better than others configurations for this stage of the amp. The sound is clearer and have better dynamic.


----------



## amphead

I'm really close to pulling the trigger on purchasing this benchtop milling machine(SIEG X3). It will produce some awesome amplifier chassis.  Thoughts?


----------



## MoodySteve

amphead, what's the maximum X/Y excursion for the platter? what size shank does it accept?

 I suppose owning a full-size Mill Rite or Bridgeport is out of the question? 

 I dream of having one of those babies in a garage one day.


----------



## adamus

do it, you know that deep down it makes so much sense.


----------



## MoodySteve

Checked out the specs. Go for it! Let us know how you like it!


----------



## pabbi1

I cheaped out with the Ryobi, but, it is way nicer than what I had before... if it makes sense, dew eet.


----------



## digger945

^I've been eyeing the Ryobi drill press at Home Depot until I saw that pic that Amphead posted above.
 Looks very similar to a Grizzly product.


----------



## amphead

Yes it is. Here's the link. I might have to sell something to help finance it. 

G0463 Mill / Drill


----------



## amphead

Yes it is. Here's the link. I might have to sell something to help finance it. 

G0463 Mill / Drill


----------



## digger945

Yea I ended up searching until I finally found it. A bit pricey(for me right now) but wow, it sure does get the wheels turning upstairs.
 Yea I could see myself selling some stuff to help pay for one of those, easy.


----------



## bhjazz

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Yes it is. Here's the link. I might have to sell something to help finance it. 
G0463 Mill / Drill_

 

Holy....
 After drilling something using a friend's press (with wildly _UN_calibrated heads...yikes) this looks deliciously perfect. Is that drilling capacitor a little small at 1" or am I just uninformed? Mayb e I'm thinking that for $1K it should have a drilling capacity of...well, more.

 [size=xx-small]/what can i sell....what can I sell...[/size]


----------



## breizheau

STOOOOOOOOOP !
	

	
	
		
		

		
			





 It took me 2 days to read the whole thread and its 2330 posts....
	

	
	
		
		

		
		
	


	



 I have already asked Jeff to send me 2 kits to build a balanced Bijou and i hope i will receive them when i will be back in France (after staying 9 years abroad....).
 I have already in progress a Dynalo SE for my Senn HD600 and i like DIY !
	

	
	
		
		

		
		
	


	




 I already built a pass-like preamp, the "UGS", and i have to finish my pass-like amp, the "UP". Sounds great !
	

	
	
		
		

		
		
	


	




 Speakers witll be my next step.
 My cans are a Senn 600 with SAA Equinoxe cable and a newly ordered Beyer 990/600 Ohms that i will recable with a balanced SAA Equinoxe cable.

 I rode on this thread that it's not so good to do separate enclosure, 1 for the PS and 1 for the amp. Could you tell me why ???????
	

	
	
		
		

		
		
	


	




 For the volume control, i already have a Relays attenuator bought at Dantimax (in Danmark). I think i will receive the kit (encoder+remote control) this week.

 I received PF3 teflon caps for the ouput caps.

 What else....? 
	

	
	
		
		

		
		
	


	




 I don't know ! 
	

	
	
		
		

		
		
	


	




 An idea for the enclosure : wooden sides + alu upper plate and front plate.


----------



## breizheau

Oops, forgot to tell you this....

 I will not use the NFB because i think it's not so easy to do it with a single pot (balanced version.....). But i have an idea :

 I think to use a 4 positions switch with attached resistors to do a "0-25%-50%-100% NFB" , double row because balanced version (but i think you know now !
	

	
	
		
		

		
		
	


	




), or a stereo attenuator DACT-like / 23 steps with the good resistors

 Is it "good" to think about a switch to "select" a "32 - 300 - 600 Ohms headphones" ? What i should add different valu caps or something else ? 
	

	
	
		
		

		
		
	


	




 I think to put in the same enclosure the RCA/XLR converter described by amphead with a switch to select "balanced / unbalanced input" on the front panel. I hope it will not be so difficult to do with perf boards and relays (i still have some in my trunk).

 I will also put balanced and SE plugs on the front panel.

 Transformer : i have asked to a french company (ABL) a quotation for a custom made transformer with 2 x 260-0-260V@100mA + 2 X 6,3V@3.5A.
 If it's not good to have only 1 trafo, i will ask for 2. They work very well (already asked them for toroid trafos)

 The enclosure :

 i have to draw it with sketchup because i's not so easy to describe what i would like to do ! 
	

	
	
		
		

		
		
	


	



 But the idea is to have 2 separated enclosures (amp+PS linked by a cable with Ebay military connectors).
 On the amp enclosure, i think about a "ribbon" at the bottom of the front panel with the XLR + jacks plugs. 
 Just above, a tilted panel with :
 - Volume control knob
 - RNB switch
 - ON/OFF switch
 - balanced/unbalanced input switch
 - Z|Headphones| switch (to be defined....)

 Siver wire is already ordered (20AWG shielded Twisted pair + 22AWG shielded Twisted pair + 20AWG shielded 3 wires twisted) to Navship !
	

	
	
		
		

		
		
	


	




 Hoping you don't take me for a completely nuts guy ! 
	

	
	
		
		

		
		
	


	




 Olivier 
 (Thx Dantes for the PM and Pabbi1 to show me this way)


----------



## amphead

Theoretically it could work to have a separate power supply enclosure. Using a single enclosure avoids some hassles with heater connection issues, between 2 enclosures. Especially to avoid noise, there will be some work to do. Welcome to the Bijou project!


----------



## pabbi1

I still listen to my Bijou daily - it has a rather unique voice. That said, I am hearing a Raven's call for my hd800... we'll see which is better, or rather, which I prefer. This is how she looks right now...


----------



## breizheau

Thank you.


----------



## rolotube

breizheau, I am running separate PS & amp chassis, with some success. Many solid state builds I have completed prior to the Bijou convinced me this method has merit, particularly for minimising the effects of AC artifacts in the signal path. Of course, complete isolation is next to impossible in a valve amp where AC filaments & DC HV lines coexist in close proximity, but a well executed design comes very close. IMO, the Bijou layout, which I have more or less followed, is such a design.

 I am using two small diecast aluminium boxes on which the amp & PS components are mounted connected by two 3-core mains leads using XLR plugs & sockets, one each for the HV & AC heaters. The third conductor is earthed to the star ground at both ends. My build is dead quiet - totally black - at all attenuator positions. I am using amphead's heater mods (a 100R resistor to earth across each side of the 6.3V heater wiring). I'm not using any shielded cable - all signal wiring is Jupiter 5N's solid core Ag with cotton insulation. Nor am I running any feedback, as my cans of choice are HD650's with SAA Equinox cable.

 Other mods include film caps everywhere using Mundorfs (M-Cap (C1), Supreme Silver/Oil (C3,4), TubeCaps (C5 & PS)) & Jupiter Beeswax/Paper (C6); choke PS mod (variation 1); regal's mods (increased idle current); EH 6H30Pi, JJ ECC99, 370DAX, DACT CT2, etc.

 Sound is fabulous. Still burning in but it is opening up beautifully & has fundamentally altered my view of what "high fidelity" sound really is.

 Hats off to Alex, Jeff & all developers & forum members for a great project.

 Tony


----------



## breizheau

Thx Tony 
	

	
	
		
		

		
		
	


	




 I still have to work on the design but one like the Mcalister looks very nice...


----------



## TimJo

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_I am using two small diecast aluminium boxes on which the amp & PS components are mounted connected by two 3-core mains leads using XLR plugs & sockets, one each for the HV & AC heaters. The third conductor is earthed to the star ground at both ends. My build is dead quiet - totally black - at all attenuator positions. I am using amphead's heater mods (a 100R resistor to earth across each side of the 6.3V heater wiring). I'm not using any shielded cable - all signal wiring is Jupiter 5N's solid core Ag with cotton insulation. Nor am I running any feedback, as my cans of choice are HD650's with SAA Equinox cable.

 Other mods include film caps everywhere using Mundorfs (M-Cap (C1), Supreme Silver/Oil (C3,4), TubeCaps (C5 & PS)) & Jupiter Beeswax/Paper (C6); choke PS mod (variation 1); regal's mods (increased idle current); EH 6H30Pi, JJ ECC99, 370DAX, DACT CT2, etc._

 

Do you feel like posting some pictures of your build?


----------



## V-DiV

Quote:


  Originally Posted by *TimJo* /img/forum/go_quote.gif 
_Do you feel like posting some pictures of your build?_

 

I'd like to see it too.

 I'm moving along slowly on my build. I've finished stuffing the boards. Here is a quickie pic (not great b/c I didn't bother to go and set up my tripod).






 I'm going to air wire tube sockets to the top panel. The wood in the picture is maple for my frame. It's already cut and routed. I have some free time this week. I hope to get the case built and stained in the next couple of days. Who knows, I may start to power up by the weekend. Lots of little details to attend to along the way though.


----------



## breizheau

look nice.


----------



## breizheau

I received the quotation for my trafo, costumed made by my favourite manufacturer. 
 Primary : 230V / Secondary : 260-0-260V@200mA | 6,3V@4A, 46 USD each + shipping fees.
 Sure they will be less beautiful than the Hammonds but for me it's the best solution.


----------



## rolotube

Here are a few lo-fi shots of my Bijou. Unlike many builds shown on this forum, it isn't pretty & some of it doesn't even fit on the chassis! I'm waiting on a couple of slightly larger Hammond chassis with perforated covers, which should finish it off functionally, if not very aesthetically. C1,3,4&6 reside inside the amp "box". HV & heater connecting cables are about one metre long which allows good physical separation of the amp & PS. I wouldn't go past about two metres unless using very HQ cables as heater voltage drop becomes a problem. Next mods will be trying Shinkoh/Caddock resistors in critical places & Blackgates for C2 in amp & C3 in PS). Not sure this will make much difference but there's not much else left to play with! I'll also try the kit NOS 6922's & 6N6P's as well as 6N1P's.


----------



## funch

Thread killer. NVM.


----------



## amphead

Interesting breadboarding technique Rolotube!

 Well, I'm considering this mini-lathe (7 x 10) from Harbor-Freight for $349.99 with a $100.00 discount. Unfortunately I received a rain-check, so who knows when they would re-stock it. It weighs 89 lbs, so it's semi-portable, and can turn up to 2 and 3/4 inch(diameter) material. I'm thinking about knobs, push-switches, connectors and illuminating devices.


----------



## V-DiV

Rolotube, your Bijou must sound awesome. As you say, I am finding that going from the merely functional (casing) to the esthetically pleasing may be the hardest part of the whole project. 

 Amphead, you're really getting into a machine shop mindset. When are you going to start taking orders for custom knobs? 
	

	
	
		
		

		
		
	


	




 Funch, YGPM.


----------



## rolotube

Thanks amphead.

 Lathe looks nice. No doubt your builds will be stunning both aesthetically & aurally once you get the hang of this beast. I greatly admire the effort & imagination that has gone into many of the builds shown on both this & Headwize forums. I've always subscribed to the philosophy of "form follows function", so whilst they always work well enough, my projects could only be described as utilitarian in appearance. I'm working hard on changing my philosophy to produce more aesthetic builds in future!

 Breadboard wasn't exactly part of the plan. Both amp & PS fitted very neatly on the two diecast boxes when using the stock caps. With two thick cables joining the chassis, the whole rig looked cool. But the robust dimensions of the Tubecaps, as well as the Hammond choke, presented a space challenge that was insurmountable with the original build. The current set up is temporary, a "proof of concept". Before committing to larger chassis, I wanted to be certain the Tubecaps were worth the effort & expense of a new layout & build. I'm now convinced they are. Compared to the electrolytics, the Tubecaps have tightened up the sound significantly, especially the bass. Before, there was an abundance of it, possibly too much. At times, I thought it may have been a little flabby. Now it is still there, perhaps not quite the with extreme extension that there was, but it is much tighter, more controlled & ultimately, less fatiguing.

 However, the most striking aspect of the Bijou to me is its extraordinary ability to resolve detail. I have never, ever heard anything do this so well. Individual instruments are separated from a group or orchestra, & then what sounds like 3D space or "air" is created around them. Voices, particularly female, are projected & seem to float above the accompanying instuments. I'm hearing detail & subtle nuances in many of my most played recordings that I've never heard before. I notice yourself, regal & others have mentioned this as well in earlier posts. I suspect this is an inherent characteristic of the design, rather than solely the use of esoteric components. Good quality parts may help, but they are only part of the equation. A total absence of fatigue (& reluctance to switch it off!) even after long listening sessions is another outstanding quality of this amp.

 Perhaps yourself or someone else could shed some light on a question I have regarding the output & bypass caps, C5&6. I replaced the stock items with a 200uF Tubecap & 1uF Jupiter Beeswax/Paper respectively. There was an immediate & less than subtle improvement in the soundstage & focus of instruments & voices. My rationale for the change is that 1) film caps are supposed to be better in such positions than electros, 2) Mundorf make a reasonable quality film cap, 3) earlier posts led me to believe that a value significantly lower than 470uF wouldn't necessarily compromise bass response, especially when feedback isn't used, & 4) I read some very good reviews of Jupiter caps in bypass situations. My question is, is there anything to be gained by retaining a high quality bypass cap with a good quality film output cap i.e. is it redundant? Are there contraindications for bypassing a film cap with a paper dielectric one? Would there be any danger in removing it for a trial?

 Comments & opinions would be most welcome.

 Thanks.


----------



## rolotube

Quote:


  Originally Posted by *V-DiV* /img/forum/go_quote.gif 
_Rolotube, your Bijou must sound awesome. As you say, I am finding that going from the merely functional (casing) to the esthetically pleasing may be the hardest part of the whole project. 

 Amphead, you're really getting into a machine shop mindset. When are you going to start taking orders for custom knobs? 
	

	
	
		
		

		
		
	


	




 Funch, YGPM._

 


 Awesome is an accurate description. Its been a revelation compared to anything else I've heard. There have been definite improvements, sometimes not so subtle, with every change I've made. As references, I have a Lehmann Black Cube, Perreaux SXH1 & custom built bipolar Class A discrete amp, all of which have good to excellent performance with my HD650's. But the Bijou absolutely smokes them all, in every respect. Although there are many excellent solid state designs around, I now have no inclination whatsoever to move back to them. I had no idea valve (tube) amps could sound so good. Its been worth every hour (& not a few $$'s!) spent.


----------



## pabbi1

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_However, the most striking aspect of the Bijou to me is its extraordinary ability to resolve detail. I have never, ever heard anything do this so well. Individual instruments are separated from a group or orchestra, & then what sounds like 3D space or "air" is created around them. Voices, particularly female, are projected & seem to float above the accompanying instuments. I'm hearing detail & subtle nuances in many of my most played recordings that I've never heard before. I notice yourself, regal & others have mentioned this as well in earlier posts. I suspect this is an inherent characteristic of the design, rather than solely the use of esoteric components. Good quality parts may help, but they are only part of the equation. A total absence of fatigue (& reluctance to switch it off!) even after long listening sessions is another outstanding quality of this amp._

 

Sorry I can't add anything on the caps, but I am so glad to hear someone else appreciate the 'air', space and resolution this amp provides - especially balanced. Fishski had it for a while (not sure about his current status), but this is just mesmerizing for the most part - and hearing everything in the music is somewhat startling in that it is so foreign - takes a bit of getting used to. And, that is without the Regal mods, and using the cheap Russian tubes. 

 That all said, it is an acquired taste, that many simply do not seem to care for. I dig it, but it takes time to appreciate what it does.


----------



## funch

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_
 However, the most striking aspect of the Bijou to me is its extraordinary ability to resolve detail. I have never, ever heard anything do this so well. Individual instruments are separated from a group or orchestra, & then what sounds like 3D space or "air" is created around them. Voices, particularly female, are projected & seem to float above the accompanying instuments. I'm hearing detail & subtle nuances in many of my most played recordings that I've never heard before. I notice yourself, regal & others have mentioned this as well in earlier posts. I suspect this is an inherent characteristic of the design, rather than solely the use of esoteric components. Good quality parts may help, but they are only part of the equation. A total absence of fatigue (& reluctance to switch it off!) even after long listening sessions is another outstanding quality of this amp.
_

 

Amen, brother!!


----------



## runeight

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_Thanks amphead.

 Lathe looks nice. No doubt your builds will be stunning both aesthetically & aurally once you get the hang of this beast. I greatly admire the effort & imagination that has gone into many of the builds shown on both this & Headwize forums. I've always subscribed to the philosophy of "form follows function", so whilst they always work well enough, my projects could only be described as utilitarian in appearance. I'm working hard on changing my philosophy to produce more aesthetic builds in future!

 Breadboard wasn't exactly part of the plan. Both amp & PS fitted very neatly on the two diecast boxes when using the stock caps. With two thick cables joining the chassis, the whole rig looked cool. But the robust dimensions of the Tubecaps, as well as the Hammond choke, presented a space challenge that was insurmountable with the original build. The current set up is temporary, a "proof of concept". Before committing to larger chassis, I wanted to be certain the Tubecaps were worth the effort & expense of a new layout & build. I'm now convinced they are. Compared to the electrolytics, the Tubecaps have tightened up the sound significantly, especially the bass. Before, there was an abundance of it, possibly too much. At times, I thought it may have been a little flabby. Now it is still there, perhaps not quite the with extreme extension that there was, but it is much tighter, more controlled & ultimately, less fatiguing.

 However, the most striking aspect of the Bijou to me is its extraordinary ability to resolve detail. I have never, ever heard anything do this so well. Individual instruments are separated from a group or orchestra, & then what sounds like 3D space or "air" is created around them. Voices, particularly female, are projected & seem to float above the accompanying instuments. I'm hearing detail & subtle nuances in many of my most played recordings that I've never heard before. I notice yourself, regal & others have mentioned this as well in earlier posts. I suspect this is an inherent characteristic of the design, rather than solely the use of esoteric components. Good quality parts may help, but they are only part of the equation. A total absence of fatigue (& reluctance to switch it off!) even after long listening sessions is another outstanding quality of this amp.

 Perhaps yourself or someone else could shed some light on a question I have regarding the output & bypass caps, C5&6. I replaced the stock items with a 200uF Tubecap & 1uF Jupiter Beeswax/Paper respectively. There was an immediate & less than subtle improvement in the soundstage & focus of instruments & voices. My rationale for the change is that 1) film caps are supposed to be better in such positions than electros, 2) Mundorf make a reasonable quality film cap, 3) earlier posts led me to believe that a value significantly lower than 470uF wouldn't necessarily compromise bass response, especially when feedback isn't used, & 4) I read some very good reviews of Jupiter caps in bypass situations. My question is, is there anything to be gained by retaining a high quality bypass cap with a good quality film output cap i.e. is it redundant? Are there contraindications for bypassing a film cap with a paper dielectric one? Would there be any danger in removing it for a trial?

 Comments & opinions would be most welcome.

 Thanks._

 

Thanks for the very nice comments rolotube. It was this quality that I heard right away with my prototype unit. And this amp is not as good as the ones you guys are building.

 Capacitors are funny things and the way people respond to them is also very subjective. For the most part bypassing a bypass cap with a film cap shouldn't really change anything. But, I never really know how anyone will respond to these kinds of changes.


----------



## chobint

@ rolotube
 ...man I should have thought of installing terminals for c5. I've had to desolder my output caps every time I fix/modify my amp boards.


----------



## chobint

double post


----------



## rolotube

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Sorry I can't add anything on the caps, but I am so glad to hear someone else appreciate the 'air', space and resolution this amp provides - especially balanced. Fishski had it for a while (not sure about his current status), but this is just mesmerizing for the most part - and hearing everything in the music is somewhat startling in that it is so foreign - takes a bit of getting used to. And, that is without the Regal mods, and using the cheap Russian tubes. 

 That all said, it is an acquired taste, that many simply do not seem to care for. I dig it, but it takes time to appreciate what it does._

 

Pabbi
 Your balanced Bijou must produce some extremely sweet music. I've been considering a balanced config for some time. I think it would take all components in the chain - DAC, amp & headphones - to the next & probably highest performance level. My DAC (Musical Fidelity A324) only has single ended output, so I'm confined to this for the present. Next major project is a balanced output DAC, but this won't happen for some time. In the meantime, I believe the Bijou offers much to "play" with should one get the desire to stop listening! The Hammond chassis I ordered a while ago have just arrived so I'll be busy with rebuilding for a while. If anyone is interested, I'll post photos of the new build as it progresses.

 Regarding "cheap" Russian tubes, I have briefly tried some Sovtek 6N1P's (new) & am currently using EH 6H30Pi (gold pins). Both these tubes are not expensive yet, IMO, offer perfectly acceptable performance. The 6N1P is very forward & the sound is "in your face". It also has a lot more gain than the 6H30, which is laid back, almost to the point of sounding delicate with some music types & has incredible space & air around the music. I haven't properly auditioned the 6922; this is on the "to do" list. I rapt in the sound of the 6H30 & reluctant to make further changes whilst I'm rediscovering many of my favourite recordings. Also, I haven't tried the 6N6 in the output as yet. As with other mods including amphead's heater wiring & no feedback for high impedance phones, the ECC99 was strongly recommended by forum members as an alternative to the 6N6 kit tube, so this is what I started with. I'll eventually roll in all the tubes I have. It shouldn't be a problem running any combination of these as the EZ81/6CA4 & 370DAX can handle the extra current required.

 Regal's mods - I'm using Vishay/Dale for R2,5,6,7 & Kiwame carbon film for R3. Sound is similar to what regal describes ie. a tighter, more forward & punchier sound. Vocals & instrumental solos are more pronounced & forward than at the stock low idle current, but I wouldn't describe the sound as "better". Its just different, & will appeal to different listeners with different music types.

 The number of possible permutations & combinations of components is almost endless & each one offers the potential for a different listening experience. I really enjoy experimenting with these to find the combination(s) that hit the "sweet spot". This is the reward of high end DIY that the Bijou offers.


----------



## rolotube

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Sorry I can't add anything on the caps, but I am so glad to hear someone else appreciate the 'air', space and resolution this amp provides - especially balanced. Fishski had it for a while (not sure about his current status), but this is just mesmerizing for the most part - and hearing everything in the music is somewhat startling in that it is so foreign - takes a bit of getting used to. And, that is without the Regal mods, and using the cheap Russian tubes. 

 That all said, it is an acquired taste, that many simply do not seem to care for. I dig it, but it takes time to appreciate what it does._

 

Pabbi
 Your balanced Bijou must produce some extremely sweet music. I've been considering a balanced config for some time. I think it would take all components in the chain - DAC, amp & headphones - to the next & probably highest performance level. My DAC (Musical Fidelity A324) only has single ended output, so I'm confined to this for the present. Next major project is a balanced output DAC, but this won't happen for some time. In the meantime, I believe the Bijou offers much to "play" with should one get the desire to stop listening! The Hammond chassis I ordered a while ago have just arrived so I'll be busy with rebuilding for a while. If anyone is interested, I'll post photos of the new build as it progresses.

 Regarding "cheap" Russian tubes, I have briefly tried some Sovtek 6N1P's (new) & am currently using EH 6H30Pi (gold pins). Both these tubes are not expensive yet, IMO, offer perfectly acceptable performance. The 6N1P is very forward & the sound is "in your face". It also has a lot more gain than the 6H30, which is laid back, almost to the point of sounding delicate with some music types & has incredible space & air around the music. I haven't properly auditioned the 6922; this is on the "to do" list. I rapt in the sound of the 6H30 & reluctant to make further changes whilst I'm rediscovering many of my favourite recordings. Also, I haven't tried the 6N6 in the output as yet. As with other mods including amphead's heater wiring & no feedback for high impedance phones, the ECC99 was strongly recommended by forum members as an alternative to the 6N6 kit tube, so this is what I started with. I'll eventually roll in all the tubes I have. It shouldn't be a problem running any combination of these as the EZ81/6CA4 & 370DAX can handle the extra current required.

 Regal's mods - I'm using Vishay/Dale for R2,5,6,7 & Kiwame carbon film for R3. Sound is similar to what regal describes ie. a tighter, more forward & punchier sound. Vocals & instrumental solos are more pronounced & forward than at the stock low idle current, but I wouldn't describe the sound as "better". Its just different, & will appeal to different listeners with different music types.

 The number of possible permutations & combinations of components is almost endless & each one offers the potential for a different listening experience. I really enjoy experimenting with these to find the combination(s) that hit the "sweet spot". This is the reward of high end DIY that the Bijou offers.


----------



## rolotube

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Thanks for the very nice comments rolotube. It was this quality that I heard right away with my prototype unit. And this amp is not as good as the ones you guys are building.

 Capacitors are funny things and the way people respond to them is also very subjective. For the most part bypassing a bypass cap with a film cap shouldn't really change anything. But, I never really know how anyone will respond to these kinds of changes._

 

Apologies for the double post above, I'm struggling with the technology at present!

 Runeight
 I'd suggest that the amps some are building aren't "better" than anyone else's, just different. The success or otherwise of the end result is a matter of personal opinion & interpretation. IMO, the great strength of this project are the efforts the designers, developers & builders have gone to to communicate & share the amazing range of mods & variations they have devised & tested. This has given me the inspiration to experiment with my Bijou far more than anything else I've constructed, & I'm nowhere near done yet!

 I'll try removing the bypass caps.


----------



## rolotube

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_@ rolotube
 ...man I should have thought of installing terminals for c5. I've had to desolder my output caps every time I fix/modify my amp boards._

 

chobint

 The screw terminals are great for swapping out components when you're experimenting. No soldering needed & much time saved. When the final config is reached (if ever), components can be soldered into place permanently. But I'd still use gold plated posts (standoffs) for connections to the boards to facilitate any maintenance that may be required.


----------



## holland

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_I'd still use gold plated posts (standoffs) for connections to the boards_

 

I've been looking all over the place for these. Do you have a link to a vendor?

 Thanks!


----------



## Ferrari

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_... someone else could shed some light on a question I have regarding the output & bypass caps, C5&6. I replaced the stock items with a 200uF Tubecap & 1uF Jupiter Beeswax/Paper respectively. There was an immediate & less than subtle improvement in the soundstage & focus of instruments & voices. My rationale for the change is that 1) film caps are supposed to be better in such positions than electros, 2) Mundorf make a reasonable quality film cap, 3) earlier posts led me to believe that a value significantly lower than 470uF wouldn't necessarily compromise bass response, especially when feedback isn't used, & 4) I read some very good reviews of Jupiter caps in bypass situations. My question is, is there anything to be gained by retaining a high quality bypass cap with a good quality film output cap i.e. is it redundant? Are there contraindications for bypassing a film cap with a paper dielectric one? Would there be any danger in removing it for a trial?

 Comments & opinions would be most welcome.

 Thanks._

 



 If I can recall, you are the 3rd Bijou builder (after me and chobint) who uses film caps at the output of your amp.
 However sound improvement is a very subjective matter, your impressions is quite consistent with mine.







 As for bypass cap C6 (parallel to main output cap C5), I just omitted it in my build since it seems to be redundant and doesn’t add any thing to the excellent sound quality of the 330µF MKP film output cap. I can imagine that the bypass cap C6 can bring some improvement when put it in parallel to electrolytic caps.


----------



## runeight

You know, gents, there is a way to eliminate the O/P and futterman feedback caps in the Bijou. But, it requires a split HV supply and is more dangerous to your headphones than having the protection of the O/P cap if anything goes wrong.

 If any of you are high risk builders, I can show you how to do this.


----------



## Ferrari

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_You know, gents, there is a way to eliminate the O/P and futterman feedback caps in the Bijou. But, it requires a split HV supply and is more dangerous to your headphones than having the protection of the O/P cap if anything goes wrong.

 If any of you are high risk builders, I can show you how to do this. 
	

	
	
		
		

		
		
	


	


_

 


 You mean something like ±125V configuration?
 However I prefer to play safe, I would love to know what you have in mind.


----------



## runeight

Ferrari, you might actually be able to do this. I have already tested in in a slightly different amp and the O/P DC is very stable if the PS is stable.






 Will need +/-15V for the opamp. Or maybe even +/-5V.

 The PS complexity is one of the main reasons I didn't do this for the original Bijou. We have gone from one B+ supply to 5 supplies including the opamp. It's just more build complexity.

 But, the two caps associated with the output are now gone.


----------



## rolotube

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_I've been looking all over the place for these. Do you have a link to a vendor?

 Thanks!_

 

holland, I may not have explained myself very well in describing these. I'm referring to small gold plated steel or brass pins about 1 to 1.5 cm long with a shoulder half way along their length. You solder one end into the component or wire connection hole on the PC board & the external component or connecting wire to the projecting end. It eliminates having to remove the boards when changing components, but still requires a soldered connection.

 I obtain them from a Jaycar, an electronics parts supplier near where I live. If you are in Australia, you should be able to source them from your local Jaycar, DS Electronics or Altronics. If they are what you require, PM me with your details & I'll send you a packet.


----------



## rolotube

ferrari, your Bijou build looks stunning. I wish I had the patience & flair to create such an aesthetic piece.

 Regarding the OP & bypass caps, I noticed the biggest difference (improvement) when the stock 470uF electro was bypassed with the Jupiter 1uF. The move to the Mundorf 200uF Tubecap was an improvement, for certain, but not to the same extent. I was very happy with the sound using the good bypass & electro OP cap, but I had already purchased the Mundorfs & was keen to try them. But I won't be going back, as the sound is now very much the way I like it - full & extended in frequency range, but delicate & 3D-like at the same time. It is, however, very critical of source material. My impression is that there's a synergy of the components in the build as it now exists. The challenge I have is to put the whole plot together in a more rational, organised & aesthetic build on a couple of new chassis.

 I will disconnect the Jupiter bypass cap & report back with some impressions.


----------



## amphead

Nice Alex! That would definitely be interesting to hear vs the stock PS configuration.

 Well I pulled the trigger on a slightly longer mini-lathe the Harbor-Freight 7" x 12". Eventhough I called the order in last night, it won't be processed until Monday. It looks similar to the other...........


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Sorry I can't add anything on the caps, but I am so glad to hear someone else appreciate the 'air', space and resolution this amp provides - especially balanced. Fishski had it for a while (not sure about his current status), but this is just mesmerizing for the most part - and hearing everything in the music is somewhat startling in that it is so foreign - takes a bit of getting used to. And, that is without the Regal mods, and using the cheap Russian tubes. 

 That all said, it is an acquired taste, that many simply do not seem to care for. I dig it, but it takes time to appreciate what it does._

 

my Mundorf output film caps are still sitting on my workbench, waiting for a Bijou chassis to be built. the amp circuitry will be P2P. no plans to go balanced at this point. i have to finish some projects for a couple of friends first: a preamp/CK2III with an off-board PS and LM7805 regulator to power an on-board gamma-1 DAC; a P2P Gainclone; and a High Octane tube guitar amp. 

 rolotube,
 it's nice to see another Bijou build.

 V-Div,
 i find the lay-out and chassis build to be the most time consuming and challenging part of DIY. it's quite rewarding to have an aesthetically pleasing and good sounding piece of DIY sitting on the hi-fi rack, and well worth the sweat.


----------



## TimJo

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_You know, gents, there is a way to eliminate the O/P and futterman feedback caps in the Bijou. But, it requires a split HV supply and is more dangerous to your headphones than having the protection of the O/P cap if anything goes wrong.

 If any of you are high risk builders, I can show you how to do this. 
	

	
	
		
		

		
		
	


	


_

 

I've been looking at the schematic, and it looks like a very cool design. What is the most probable failure mode - the ECC99 going south or the opamp losing control?

 Would an e12 monitoring the output provide enough safety?

 Looks like a good p2p candidate....


----------



## runeight

An e12 will be necessary on the O/P to prevent damage from DC offset problems. But the e12, because it is electro-mechanical is not fast enough to handle certain kinds of failures. Like the ones you're asking about.

 If the opamp goes while the amp is working the O/P will slew to one of the rails pretty quickly. And because the voltages are so high the e12 may not cut off in time.

 Tube failure of the kind that would matter here is rare. A direct plate to cathode short or arc would put HV on the headphones almost immediately. The e12 won't even see this type of transient. Protecting against it is like protecting against an asteroid hitting the earth. It happens so rarely that it may not be worth the trouble but when it does happen dinosaurs die. 
	

	
	
		
		

		
		
	


	




 Nonetheless, I have built this O/P stage and I know that the opamp will zero the DC offset and keep it under 10mV if the split PS is regulated.

 So the only way to prevent catastrophic failure will be to have a current limited PS so that even if there is a transient it's not large enough to damage headphones. This is actually possible with a shunt regulated PS.

 This all can be done if someone really wants to get rid of those O/P caps.


----------



## pabbi1

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_my Mundorf output film caps are still sitting on my workbench, waiting for a Bijou chassis to be built. the amp circuitry will be P2P. no plans to go balanced at this point. i have to finish some projects for a couple of friends first: a preamp/CK2III with an off-board PS and LM7805 regulator to power an on-board gamma-1 DAC; a P2P Gainclone; and a High Octane tube guitar amp._

 

And I thought I was crazy with two electrostat amps, and an idht dynamic amp...

 Ron, I looked at that lathe at HF yesterday (they were having a big sale), as it was right next to the dovetail jig (my real target). It was probably the nicest machine in the store (ok, not saying a whole lot for HF), but I was a bit tempted myself. You will do well with that.


----------



## Ferrari

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Ferrari, you might actually be able to do this. I have already tested in in a slightly different amp and the O/P DC is very stable if the PS is stable.

 ...

 Will need +/-15V for the opamp. Or maybe even +/-5V.

 The PS complexity is one of the main reasons I didn't do this for the original Bijou. We have gone from one B+ supply to 5 supplies including the opamp. It's just more build complexity.

 But, the two caps associated with the output are now gone. 
	

	
	
		
		

		
		
	


	


_

 

You are right, it’s indeed a trade-off between OCL and an increasing complexity of the PS.
 The low symmetrical PS (±5V… ±15V) for the DC servo circuit should not be a problem, a simple PS based on 78xx/79xx should be sufficient here. 
 More critical is the symmetrical ±125V, this circuit should be very solide in order to guarantee a stable DC offset at the output.

 For the moment I would love to let my Bijou as it is, since I listen to it every day and it sounds great (CAN'T miss it). 
	

	
	
		
		

		
		
	


	



 But I still have a couple of PCB’s in my drawer, and I will certainly try your proposed schematic out as soon as I have time.
 If it turns out as what we are thinking, then we have a winner: a Bijou with the best output cap up to now (OCL & OTL).
 If it doesn’t for whatever reason, no problem at all… we all know that’s the nature of R&D.


----------



## rolotube

As I understand it, a fundamental principle in the the initial design of the Bijou was simplicity. The idea was to use just one PS, the trade-off being a requirement for an OP capacitor. Whilst it may not be the most elegant solution, the simplicity of this is what attracted me in the first place. I can appreciate the virtues of a symmetrical PS, but loosing the OP cap in favour of greater complication takes the design outside its original brief, IMO. That being said, it would still be a very interesting exercise. But as reliable as modern parts are, I'm not sure I'd want to risk my expensive HD650/K701's trying it. With my luck, Murphy's Law would be likely to intercede & if just one critical component went south, that would be the end of them.

 There are plenty of HQ caps available, both electro & film, that will do an admirable job of coupling the output to the headphones. Part of the interest & fun of DIY is trying different combinations to see what works best for individual builds. IMO, this is a "no risk" solution that has the potential to be near as damn-it in terms of sound quality to a no-OP cap design, if the components are chosen carefully. 

 I'm sure its possible, but I find it very difficult to imagine how the sound of the Bijou could be greatly improved beyond application of the mods that have been suggested & use of top shelf parts. I think its evolved to be hard up against the vertical part of the curve of the law of diminishing returns, where an exponential amount of time, effort & money would need to invested to extract a very small amount of gain.

 Just my thoughts.


----------



## pabbi1

Shunt regulators, you say? 
	

	
	
		
		

		
			





 Very soon, very small, pretty simple, so, may yet follow the Bijou philosophy, even if they were designed for the uber stat amp.


----------



## runeight

Yes, those were my design goals when I did the Bijou design. And it is a remarkably simple tube amp for how good it sounds.

 But diyers being what they are, there are always some who find it a challenge to squeeze out the last bit of better. I don't know if removing the O/P caps here would change the SQ, but it might - to some ears.

 In any case, there are many projects to work on right now. This one will have to wait. Thanks for your most generous comments on the sound of this amp. It was this SQ of the proto version that convinced me to make an effort to make the amp more widely available. It is always great to hear from someone who is happy with theirs.


----------



## runeight

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Shunt regulators, you say? 
	

	
	
		
		

		
		
	


	




 Very soon, very small, pretty simple, so, may yet follow the Bijou philosophy, even if they were designed for the uber stat amp._

 

Pabbi1, you are teasing us.


----------



## pabbi1

Nah, it is just taking for freaking ever, but looks like it is coming around the bend... over on Diyaudio.


----------



## runeight

Ah, I see. But with the schematics that I saw (and I did not poke around a lot), it's not a high voltage regulator. Is there a HV version?


----------



## pabbi1

HV version - though I am NOT as well read on this one.


----------



## TimJo

Thanks for the links Pabbi1...


----------



## pabbi1

N/p - it is a big world, and just amazing how things cross pollinate.


----------



## rolotube

Could someone please enlighten me as to why C1 is an electro? I'm no expert on the finer points of the Futterman design but it looks to me like its in the signal path & therefore may have a significant influence on the amp's sound. Is it this critical? Would there be any benefit in replacing it with a HQ film cap of same or similar value I happened upon a discussion about this some time ago but can't find it again.

 Thanks.


----------



## runeight

When I did the design my goal was a high performing tube amp at as low cost as possible and as easy as possible for those builders who had never built a tube (and HV) amp before. I used the simplest choices for components wherever possible knowing that upgrades could be made by anyone who had a mind to. I also wanted to keep the footprint (boards) as small as possible.

 That said, you are absolutely correct. The return cap is in the signal path and there will be some benefit to using a non-electrolytic cap here.


----------



## rolotube

runeight

 Thanks for the clarification. My main concern was, given that an electro had been specified for C1, using a film cap in this position would not compromise performance. I have been running a Mundorf M-Cap (15uF) for some time, with no ill effects that I can detect, but recently had a moment of uncertainty. Hence the question.

 BTW, dropped the bypass (C6) off the 200uF Tubecap (C5) a few days ago & I cannot detect a significant change in sound quality. In the spirit of the project, simpler is better, so I'll leave it off. The most significant change between the 200uF Tubecap & 470uF electro is a slight contraction in the amazing bass extension that the amp possesses (this may be due the smaller capacitance value??), but the overall sound is tighter & more focussed. Not a bad trade-off, IMO.


----------



## runeight

Yes, I think that's exactly right. With the smaller cap the bass will roll off a bit faster but it should clarify a bit also.


----------



## amphead

That should sound quite good Rolotube, with bass heavy phones like the senns. It would tame their boominess possibly for some configurations of the Bijou. I hadn't considered output coupling with a low-value high-quality film cap, Bravo!

 Well the lathe came today, and here's some pics after cleaning off the cosmoline red packing grease, and lubing it with lithium grease and paraffin oil.......


----------



## Fast3d

Here's what I've done so far. I stuck to the stock caps except the Rubycon's Thanks Pabbi1 for them. I was thinking about ordering Sonicaps and hearing the difference before and after. Amphead I'll be your first customer. I need some Volume knobs.  You guys have a good forum going here. Glad I joined.
 Sorry for Blurred PIC best I can do with Camera phone. Will take better pics once done.


----------



## runeight

Looks like progress to me. 
	

	
	
		
		

		
		
	


	




 When do you fire it up?


----------



## Fast3d

Soon I hope. Still waiting on the Ecc99 and the transformer.


----------



## breizheau

I received my parcel from Jeff today.. 
	

	
	
		
		

		
			




 Just need now to find a new flat and to get my truncks !
	

	
	
		
		

		
		
	


	




 All my tools are inside.
 Can't wait to hear this "jewel"


----------



## amphead

That's good news Breizheau! We look forward to your build.

 Here is a picture of the first aluminum chips coming off of a volume knob for the Bijou. Assuming I don't switch to stainless steel..........


----------



## breizheau

I will order my trafas when i will be settled.... I asked for customized with 230V primary and 260-0-260 @ 200 mA and 6.3V@4A for secondaries. With covers, the prices are the cheapest i have !!! For 2 pieces made in my country, the price is equal with 1 piece ordered abroad.....
	

	
	
		
		

		
		
	


	



 i just have to wait now for my tools.


----------



## balderon

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_That's good news Breizheau! We look forward to your build.

 Here is a picture of the first aluminum chips coming off of a volume knob for the Bijou. Assuming I don't switch to stainless steel..........

http://i207.photobucket.com/albums/b...firstchips.jpg_

 

Very nice @amphead! I had some custom machining done for my Bijou project and the cost was a little pricier than I wanted. I wish I could justify purchasing a lathe. Congrats! When will you start taking orders?


----------



## whitelabrat

Done. At least for the electronics part for now.

 Nice amplifier. It works well with my 6bq7's but I haven't listened to them critically. The chassis ain't pretty, but it was free and provides excellent ventilation. I'll pretty it up later. I certainly won't win any awards for wiring either.


----------



## chobint

Went to a meet around indy last Saturday. I thought u guys might like to see it since people had some nice things to say about the Bijou. Seems a fair few people listened to it while my eyes were closed.
http://www.head-fi.org/forums/f45/mi...6/#post5541498

 PS. Grats on your latest purchase amphead. Looks like you'll be in for some fun.


----------



## rolotube

amphead, nice kit. I'll be in the orders queue when you move on to stainless. It will go well with my new matte black Hammond cases.

 whitelabrat, good to see another Bijou up & running. At least its physically contained, unlike mine, which is still an aesthetic nightmare sprawling over a desk in my study three months after fire up!


----------



## whitelabrat

I'd like to share some notes and impressions about my experience for folks to consider. My goals are, #1 great sound and #2 do it cheap without sacrificing #1.

 For folks looking to start a Bijou I can suggest a couple tricks to save some $. For a power transformer try the Allied 6K56VG (alliedelec.com). I ran my build for several hours and everything ran cool and quiet. Getting a regulated 250vdc was no problem with an EZ80 rectifier. It's made by Hammond, but costs less. Also keep an out out for overstock parts. I got three 470uf caps good and cheap. I would expect that even a EZ80 should work with the Regal Mods, but R7 and R8 may need to be changed for the job. The Allied power transformer should have enough of a current rating to force the EZ80 to work. I've not tested this yet though. In any case go with EZ81's whereas I already bought a bunch of EZ80's and want to make them work.

 I prefer dumping electrolytics/bypassing from the signal path so I used two pricey (for me) Solen 100uF 400v caps for output coupling which are fine for headphones down to 100 ohms. I've found that a pair of cheap 600uF ASC GLY513 caps work just as well. Go hunting for motor run caps on th' bay.

 Alps blue velvet pot vs cheap stepped attenuator? Stepped attenuator wins unless you smash it up like I did.

 Negative feedback doesn't seem to help any with 100 ohm or 600 ohm headphones. Am I missing something?

 In hindsight I would suggest the Regal Mods. The PCC88 and 6bq7 tubes I've tried seem hungry for more juice. The lows and midrange isn't as aggressive as I would like it in the stock configuration.

 Very quiet operation as I would expect from a regulated power supply.

 Thoughts for Bijou II: Constant Current Source for V1? I saw something with an opamp in it. Either unregulated PS with LC filter and tube rectifier, or completely solid state PS? How about the TIP50 thing?


----------



## whitelabrat

I wanted to post a quick followup. I tried the 6bq7's again and it sounded better (to me). I think the PCC88's need more heater voltage which makes sense being that the heaters are rated for 7v.

 The 6N1P Morgan Jones amp I cobbled together didn't like the 6bq7 for the input stage (weird tingly noises), but the Bijou seems to like them even though they're very microphonic. Excellent! They're super cheap and I've got tons of 'em. 
	

	
	
		
		

		
		
	


	




 Question about feedback. How do you know when you've got it right? Subjectively of course.


----------



## runeight

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_I wanted to post a quick followup. I tried the 6bq7's again and it sounded better (to me). I think the PCC88's need more heater voltage which makes sense being that the heaters are rated for 7v.

 The 6N1P Morgan Jones amp I cobbled together didn't like the 6bq7 for the input stage (weird tingly noises), but the Bijou seems to like them even though they're very microphonic. Excellent! They're super cheap and I've got tons of 'em. 
	

	
	
		
		

		
		
	


	




 Question about feedback. How do you know when you've got it right? Subjectively of course._

 

This is most certainly true. Running the 7V heaters at 6.3V will make the tubes sound pretty lean.

 The NFB is entirely subjective, but most listeners do notice it. If you're running 100R or higher headphones the NFB won't make too much difference. It's mostly there for the 32R headphones where you need to decrease the Zo, reduce the distortion, and increase the bandwidth of the amp when it's driving a low Z. This is because the native Zo of the amp is about 55R.

 At first it's hard to tell the difference between changing NFB and changing volume, but after some listening most folks have reported changes in the sound stage and other refinements. Some prefer no NFB all the time independent of headphones. If you are sure you'll be using 100R or higher Z phones I would leave it out.

 Thanks for the suggestions for Bijou II. If we do another version we'll try to bring in some of the changes suggested by builders. The main change will be a beefier PS so that we can run the input stage and phase splitter at at least 5mA each (regal's changes).


----------



## runeight

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_I wanted to post a quick followup. I tried the 6bq7's again and it sounded better (to me). I think the PCC88's need more heater voltage which makes sense being that the heaters are rated for 7v.

 The 6N1P Morgan Jones amp I cobbled together didn't like the 6bq7 for the input stage (weird tingly noises), but the Bijou seems to like them even though they're very microphonic. Excellent! They're super cheap and I've got tons of 'em. 
	

	
	
		
		

		
		
	


	




 Question about feedback. How do you know when you've got it right? Subjectively of course._

 


 whitelabrat are you also changing cathode resistors when you use the 6bq7s? It's not possible to arbitrarily swap tubes into the input stage of this amp. If you are not changing the cathode resistor then perhaps you could measure the plate voltage of the input triode for both the 6bq7 and the pcc88? This will give us some idea of exactly where the op point is.

 Thanks.


----------



## smeggy

A little OT here, but is there a general ranking of Bijou, SOHA II and EHHA? I'm leaning to EHHA because it fits with my plans best, but still wonder if there's a consensus.


----------



## sachu

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_A little OT here, but is there a general ranking of Bijou, SOHA II and EHHA? I'm leaning to EHHA because it fits with my plans best, but still wonder if there's a consensus._

 

I don't think not many people even know aout the EHHA let alone heard it.


----------



## whitelabrat

runeight, 

 I've not changed anything from the 6922 stock configuration. I recall somewhere buried in the post that there is enough of a difference between the 6922 and the 6dj8 that some changes may be required. The 6dj8 is an improved 6bq7 if that helps any. I'll try to pry these headphones off my head to make some measurements. 
	

	
	
		
		

		
		
	


	




 Some humor for folks. An ancient Audio Alchemy DDE v1.1 landed in my house today. It just handed a whoop to my modified E-mu 1212m. Something has to be wrong with that. I'm feeling a bit disillusioned and lovin' it.


----------



## smeggy

well, curious about all 3 but hopefully Alex may have a word to say about them all. It's pretty academic in reality but I'd still like to hear thoughts.


----------



## bhamham

Hi everyone, my first post to this thread. Got my box from Jeff yesterday. Many thanks, Jeff - great job packaging.

 NOW WHAT!!! ....haven't held a soldering iron in many years so hoping it all comes back to me. Guess I need to find a case and the other bits. This is a great thread filled with lots of friendly help. I know I'll need some as I get further along.


----------



## bhamham

Sorry, double post...


----------



## amphead

Smeggy, if you are looking to build any of the three, I think you could pull off a Bijou with some guidance here. It's very good, and you won't regret choosing it over the other two. I know all three have their merits, but I believe the Bijou just edges them out for the top tier.


----------



## runeight

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_well, curious about all 3 but hopefully Alex may have a word to say about them all. It's pretty academic in reality but I'd still like to hear thoughts._

 

I don't know . . . 
	

	
	
		
		

		
			





 They are very different amps. The Bijou is all tubes. The SOHA II is a conventional hybrid with a coupling cap between the tubes and the O/P buffers. The EHHA is an embedded hybrid, DC coupled from input to output.

 I have a Bijou and a SOHA II. I like them both quite a lot. The Bijou is a pure tube sounding amp. It's very beautiful in the ways that have been described on this thread. The SOHA II, however, is also quite nice and my wife really likes the sound of it. It's easier to tube roll and to adjust sound according to the tube used. I have EHHA boards but have never got around to building it. The EHHA will have much more power than the other two amps and is capable of driving speakers if the right PS is used, such as the sigma22 PS.

 I guess there is no answer. It just depends on what you want to try first and what kind of sound you're after.


----------



## sachu

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_I don't know . . . 
	

	
	
		
		

		
		
	


	




 They are very different amps. The Bijou is all tubes. The SOHA II is a conventional hybrid with a coupling cap between the tubes and the O/P buffers. The EHHA is an embedded hybrid, DC coupled from input to output.

 I have a Bijou and a SOHA II. I like them both quite a lot. The Bijou is a pure tube sounding amp. It's very beautiful in the ways that have been described on this thread. The SOHA II, however, is also quite nice and my wife really likes the sound of it. It's easier to tube roll and to adjust sound according to the tube used. I have EHHA boards but have never got around to building it. The EHHA will have much more power than the other two amps and is capable of driving speakers if the right PS is used, such as the sigma22 PS.

 I guess there is no answer. It just depends on what you want to try first and what kind of sound you're after._

 

As much as I would love to build Bijou..I am in the final process of placing an order for a dual sigma22 PSU to go with the EHHA kit that I am ordering from Jeff.
 Whenever the EHHA 2 prototyping begins, Alex please count me in. I definitely want to build that amp too.

 I know Don will say he prefers his Stacker..But I have always maintained..I prefer his EHHA over all the other Cavalli amps he has built with the exception of the Bijou which I haven't heard yet..hopefully I can set that right sometime next week.


----------



## pabbi1

I have both the balanced Bijou and a SOHA II (due to nasty desert conditions in Afghanistan where my brother thought it best not to kill it), and they both have merits. The SOHA II, imho, is a trickier build, and is way more flexible on rolling tubes. My thoughts on Bijou are volumous - if you want air and soundstage, Bijou is the choice.

 Bottom line, there are no wrong choices here.


----------



## whitelabrat

bhamham,

 Check out tubelab.com and the instructions for the Simple SE. It's all written for the beginner and is very well done. All of the concepts may be applied to the Bijou.


----------



## smeggy

Hmm, I was looking to the EHHA as I'll already have a S22 for my Beta and could integrate it into the box easy and keep box/wire count down... plus it's so cheap!

 A Bijou is very tempting though, mebbe both?

 Thanks all


----------



## runeight

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_Hmm, I was looking to the EHHA as I'll already have a S22 for my Beta and could integrate it into the box easy and keep box/wire count down... plus it's so cheap!

 A Bijou is very tempting though, mebbe both?

 Thanks all 
	

	
	
		
		

		
		
	


	


_

 

Well, it's hard for me to suggest otherwise.


----------



## smeggy

Damn fanboys


----------



## dBel84

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_Hmm, I was looking to the EHHA as I'll already have a S22 for my Beta and could integrate it into the box easy and keep box/wire count down... plus it's so cheap! A Bijou is very tempting though, mebbe both? Thanks all 
	

	
	
		
		

		
		
	


	


_

 

just get your @rse down here and plug yourself in to each of them and make the decision . 

  Quote:


  Originally Posted by *sachu* /img/forum/go_quote.gif 
_I know Don will say he prefers his Stacker..But I have always maintained..I prefer his EHHA over all the other Cavalli amps he has built with the exception of the Bijou which I haven't heard yet..hopefully I can set that right sometime next week._

 

 LOL , I should have lent you both for the shootout 
	

	
	
		
		

		
		
	


	




 you didn't listen to Brian's Bijou at the meet? It was really well built and sounded great 


 decisions decisions , funny how most of us end up building them all ..dB


----------



## sachu

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_just get your @rse down here and plug yourself in to each of them and make the decision . 

 LOL , I should have lent you both for the shootout 
	

	
	
		
		

		
		
	


	




 you didn't listen to Brian's Bijou at the meet? It was really well built and sounded great 


 decisions decisions , funny how most of us end up building them all ..dB_

 

I was tempted to ask you but I didn't want to push my luck 
	

	
	
		
		

		
		
	


	




 I wouldn't mind swinging over to pick up the EHHA for the rest of the week to do a side by side with the stacker.


----------



## smeggy

That's my boy


----------



## Ynis Avalach

@smeggy: I'm also struggeling to decide between the three of them beautis. And I also have built a Beta22 (balanced), but I'd really like to built a tube. Just can't decide to go full tube or hybrid, I've never had the chance to hear either of them.


----------



## emelius

any word on the super bijou?...

 i'm interested in having a balanced and se super bijou built...

 thanks...


----------



## Ynis Avalach

Quote:


  Originally Posted by *emelius* /img/forum/go_quote.gif 
_any word on the super bijou?...

 i'm interested in having a balanced and se super bijou built...

 thanks..._

 

 Uh yeah balanced super bijou!!!!
 Actually did runeight give us some hints what the main differences to the former bijou will be?


----------



## runeight

Who knows what the super Bijou will be. 
	

	
	
		
		

		
			





 And since I am buried in the CTH and Stat amps right now (with another project in the background), if you want to hear a Bijou it might be good to build the current one. A super Bijou might be a ways off.


----------



## emelius

i have heard the current bijou
	

	
	
		
		

		
		
	


	




...that's why i'm here...

 thanks for the update...guess i'll turn my focus to other things for the time being...


----------



## bhamham

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_bhamham,

 Check out tubelab.com and the instructions for the Simple SE. It's all written for the beginner and is very well done. All of the concepts may be applied to the Bijou._

 

Thanks for that whitelabrat. Excellent site and just what I needed to get started.


----------



## pabbi1

The balanced Bijou is quite nice... not sure what beyond the Regal mods would be a whole lot better.


----------



## runeight

Oh I see. I have thought that the next evolution of the Bijou should be OCL as well as OTL. But, as you saw in the earilier conversations, that's not easy in terms of protecting the headphones. Most of the work there is not figuring out the OCL output stage, but figuring out the protection circuitry. That's what will take some time.


----------



## adamus

I have been asked to build a sohaII for someone..... let the battle commence. 

 bijou vs soha II, which will come out tops?


----------



## runeight

You know, I would have a hard time with this. The liquid beauty of the Bijou is very real, but the SOHA II has some really nice qualities and I like it alot with the right tubes (right tubes for my ears). The first time my wife heard the SOHA II playing Alison Krause she started to tear up at the quality of the sound without any prompting from me.

 Once again, I don't know . . .


----------



## dBel84

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I have been asked to build a sohaII for someone..... let the battle commence. 

 bijou vs soha II, which will come out tops?_

 



 I'll cast the first wager then 

 BIJOU






 ..dB


----------



## sachu

Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_I'll cast the first wager then 

 BIJOU






 ..dB_

 


 hah!...Don..there is something about your EHHA that gets me every time I listen to it..
 This thing sounds sooo good..I love it I tell you. 
	

	
	
		
		

		
		
	


	




...the Stacker will definitely be making its way back to you first


----------



## adamus

we shall see. I am really looking forward to it!.

 The beauty of the sohaII + bijou is that i can use the same tubes for the front end, ok they are implemented very differently but the variables are slightly limited.


----------



## adamus

double post.


----------



## sachu

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_we shall see. I am really looking forward to it!.

 The beauty of the sohaII + bijou is that i can use the same tubes for the front end, ok they are implemented very differently but the variables are slightly limited._

 

hey there..I believe it was your Bijou that was there at the Portland meet...shame I wasn't able to listen to it.

 Such a neat build too..would love to hear it sometime..

 Don, the EHHA is supreme!!!


----------



## adamus

it wasnt - I'm in the uk. not such a big diy scene over here.

 this is my bijou


----------



## sachu

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_it wasnt - I'm in the uk. not such a big diy scene over here.

 this is my bijou





_

 

Wow..that is even better than the one I saw here in Portland..
 Congratulations on such a fantastic looking amp.. 
	

	
	
		
		

		
		
	


	




 Where might I ask did you source the knobs from?


----------



## adamus

i am pretty sure it was partspipe from ebay, 40mm solid alu.


----------



## bhamham

Adamus, where did you get your case? I know you posted it many pages ago - this thread reads like a Russian novel so forgive me for not searching.

 BTW, it is so lovely looking and I hope you don't mind my copying it...


----------



## adamus

I got it from modushop.biz and feel free to copy - its flattering!


----------



## whitelabrat

I've noticed my build is a bit sensitive to mains power junk. I suspect it's comming from the heater supply so I have a couple tricks up my sleeve I'd like to try. This amp will end up in my office where the mains is very noisy due to many industrial influences, so I'm going to need some extra effort to keep the power clean.

 1. DC heaters. I hate these but sometime you have to do it. I've got a nice regulated 6.3v supply that I can just drop in thanks to the external heater wiring of the Bijou. The rectifier will stay on AC since any heater noise from there will get filtered out by the power supply. Polarity should be important due to the LED.

 2. Replace R8 on power supply with 10H 270ohm choke. May need to tweak R7.

 I owe some voltage measurements which are on the to-do list. Any thoughts folks?


----------



## TimJo

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_The beauty of the sohaII + bijou is that i can use the same tubes for the front end_

 

Sounds like you need to build a CTH now, being you have the tubes already...


----------



## adamus

whitelabrat - how are you going to get 6.3v rectified and regulated off 6.3v windings?


----------



## whitelabrat

Can't from the 6.3v windings. I built the heater supply from this. It should be good up to 3A. The regulator gets very hot though so I'll need to sink it better.

 I used a 9v toroidal transformer to supply the required voltage.

 My understanding is that tubes prefer and sound better with unregulated 6.3v AC heaters, but the downside is noise.


----------



## ericj

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_I've noticed my build is a bit sensitive to mains power junk. I suspect it's comming from the heater supply so I have a couple tricks up my sleeve I'd like to try. This amp will end up in my office where the mains is very noisy due to many industrial influences, so I'm going to need some extra effort to keep the power clean.

 1. DC heaters. I hate these but sometime you have to do it. I've got a nice regulated 6.3v supply that I can just drop in thanks to the external heater wiring of the Bijou. The rectifier will stay on AC since any heater noise from there will get filtered out by the power supply. Polarity should be important due to the LED.

 2. Replace R8 on power supply with 10H 270ohm choke. May need to tweak R7.

 I owe some voltage measurements which are on the to-do list. Any thoughts folks?_

 

Why not try the easiest fix first, and see about installing a commercially available mains filter? 

 I used a filtered DC inlet module on mine. But i admit that i haven't used the amp in anything like a corporate environment.


----------



## whitelabrat

Actually I do have an outlet in the room with prime conditioned AC, but I'm prohibited for plugging into it. It's AC --> DC --> AC. Nice. Can't touch it.

 I do have both a isolation transformer and a cheap filter, and a ton of noise gets through. It sounds like a war zone from a tube amp. I had the same problem with my Bruce Bender / Morgan Jones amp. Putting a 0.47uF film cap on the B+ supply helped a bit.

 Overkill? Yes.


----------



## adamus

sure its not your source?


----------



## whitelabrat

The source is a different problem. 
	

	
	
		
		

		
		
	


	




 A SuperPro707 (v3.2) DAC landed in my house yesterday and it kicks off a ground loop. I'm going to do terrible things to it so that problem will likely go away. Other sources don't have any issues.

 I did some tests to prove it was mains. I plugged it into a spot in the house that has a quiet circuit on it with no source. No noise. Then in a noisy circuit with no source. Lots of noise. Removed noisy (an old IsoBar power strip) item from mains. Less noise.

 Little clicks and pops, and in some cases a 120hz buzz that comes from a source that I can isolate gets through.


----------



## runeight

Quote:


  Originally Posted by *whitelabrat* /img/forum/go_quote.gif 
_I've noticed my build is a bit sensitive to mains power junk. I suspect it's comming from the heater supply so I have a couple tricks up my sleeve I'd like to try. This amp will end up in my office where the mains is very noisy due to many industrial influences, so I'm going to need some extra effort to keep the power clean.

 1. DC heaters. I hate these but sometime you have to do it. I've got a nice regulated 6.3v supply that I can just drop in thanks to the external heater wiring of the Bijou. The rectifier will stay on AC since any heater noise from there will get filtered out by the power supply. Polarity should be important due to the LED.

 2. Replace R8 on power supply with 10H 270ohm choke. May need to tweak R7.

 I owe some voltage measurements which are on the to-do list. Any thoughts folks?_

 

Please see the Bijou website for two choke-based power supplies. If you haven't looked there yet.

 And, as you note, DC heaters can be good or bad, depending. Good luck with this.

 And, please let me know about those plate voltages with the 6bq7s.


----------



## whitelabrat

No modification to stock Bijou schematic.

 Voltage readings:

 6aq7 pins 1-9 in order: 249.5v, 74.5, 124.9, 6.45v (ac), 6.45v (ac), 122.6, 4.1, 2.17, shield
 6N6P-I: 199.5, 93.3, 97, heat, heat, 93, 0, 3.1, 0

 PCC88: 249.7, 74.4, 125.0, 6.47, 6.47, 122.8, 3.4, 2.17, 0
 6N6P-I: 196.2, 99.8, 103.0, heat, heat, 99.8, 0, 2.98, 0


----------



## runeight

Thanks. If these voltages are correct, this would indicate why the 6bq7s sound a little tinny.

 Pin 6 is at 122V which is 20V too high for the operating point of the first stage. But the worst measurement is Pin 1 at 249V. This says that the plate of the phase splitter is the same as the B+ which means that, basically, no current is flowing in the phase splitter.

 The only way to fix this is to adjust R2 to a smaller value until Pin 6 comes down to about 100V (actually 98V is the right value). If you do this then the phase splitter should redefine its operating point to have some current flowing.

 Your PCC88 is doing, more or less, the same thing.

 It is not possible to roll tubes without considering the whether the new, different tube type, will come to the same operating point as the original tube. In this case, it's simply not working.

 If you have time to look on the Bijou website, there is a section which gives R2 values for some popular tubes. If you want to roll tubes, it's really handy to socket R2 on both amp boards so that you can change it out with the tube.

 Once you get R2 right for the 6BQ7, let us know how it sounds.


----------



## whitelabrat

*Slap forhead*

 So I took the last couple hours and paralleled a lot of different resistors to try to get 98v. It has dawned on me that my voltage report is backwards. Should be:

 6N6P-I pins 1-9 in order: 249.5v, 74.5, 124.9, 6.45v (ac), 6.45v (ac), 122.6, 4.1, 2.17, shield
 6aq7: 199.5, 93.3, 97, heat, heat, 93, 0, 3.1, 0

 6N6P-I: 249.7, 74.4, 125.0, 6.47, 6.47, 122.8, 3.4, 2.17, 0
 PCC88: 196.2, 99.8, 103.0, heat, heat, 99.8, 0, 2.98, 0 

 I also killed my DAC yesterday. I should stop while I'm ahead. 
	

	
	
		
		

		
			





 Thanks for the help. A lightbulb went off in my head once I saw all the voltage readings. With the voltage on V1's plate at about 200v I don't think increasing the bias is needed without possibly shortening the life of the tube.

 My next question. The voltage for Pin 6 on the PCC88 seems about right on target. The 6aq7 is a bit low, but is it allowable or is 98v truly optimal?

 I'll likely need a resistor value greater than the 2k to get 98v.


----------



## runeight

LOL. It happens. 
	

	
	
		
		

		
		
	


	




 These voltages mean that you're going to need regal's mod to get a more lush sound from the amp. The 6bq7 plate voltage is ok. I wouldn't sweat it too much, particularly if you're planning to make the mod.

 But, as you say, to get to 98V you'll need slightly more than 2k. Maybe 2k4 would do the trick.


----------



## amphead

58mm stainless volume knobs being manufactured from 62mm x 12" round rod.............


----------



## TimJo

Alex, I was wondering if you would mind talking about the pros and cons of using a dual triode as a 'stereo' two channel tube (ala CTH) versus using it as a 'two-stage' tube with one tube per channel (ala Bijou and SOHA II)?

 After building the CTH, I am impressed with the sound quality with both channels of the input stage being shared by a single tube. Is there such a thing as crosstalk within a dual triode?

 I bring this up here because I am contemplating doing the Bijou as a PTP build, and was considering a topology where one tube would handle both channels of the input stage, and one tube would handle the job of phase splitting.

 Any thoughts on this notion, or should I just stick to an equivalent topology of your single channel boards?

 Edit: Just to clarify my thoughts a bit, I got to thinking about this with the idea that you could roll input tubes (like on the CTH) independently of the phase splitter tube. I began to wonder if there could be an interesting level of control and 'boutique' tweaking by dividing the two tasks into separate tubes...


----------



## runeight

Interesting you should ask this. My proto PTP Bijou does exactly what you want to do. The input stages are in one tube and the phase splitters in another. I don't think this generates any significant crosstalk and is a much easier way to do the PTP.


----------



## adamus

Mini Review: Bijou vs Soha II. 
	

	
	
		
		

		
		
	


	




 Source = Flac > camrbidge audio Dacmagic > silver interconnects.
 Phones = Recabled hd650's (old, not silver cloth version). 
 Bijou tubes = amperex bugle boys 6dj8 + 6n6p
 SohaII = amperex bugle boys.





 Let me start by saying these are both very capable amps, both have their strengths. They have a different sound signitures, very different indeed. 

 Main differences:

 The bijou is a much bigger sound and is slightly darker than the SohaII. Somehow the bijou gives a massive soundstage and creates a 3d holograph of the music. Tracks such as myriad harbour by the new pornographers creates music that reaches way past the headphones, sounding much like a good pair of distant speakers. 

 The SohaII's strength is the tight tight bass. bass tunes become stunningly clear, more so than the bijou. Its tight, but it still drops deep. It really excels on electronic music / R&B / Pop / dance. The bijou can sound slightly lose in comparison. 

 Treble, the bijou has a gorgeous fluidity, its very 'tubey' and imparts a lushness. Stick on Bon Iver "for emma" and you can drift away with the music. The SohaII is definately brighter than the bijou, its not overly bright but it certainly turns the hd650's into a quick sounding phone which is a feat on its own. The SohaII has a cooler signiture. 

 summary:

 Bijou: huge lush sound, typically 'tubey' but certainly not muddy or muffled. Think of like a big rolls royce, effortlessly turning the roughest roads into a nice journey. 

 SohaII: quicker, more agile, brighter. IT sounds more solid state to my ears, potentially truer to the recording. However, it shows up poor recordings. 

 I would be happy to have either amps, they are both superb and in a way compliment eachother well. For me, the bijou is still the king of the cavalli's, you cant compete with the spaciousness it portrays, but the SohaII is snapping at its heals, and in a sprint leave the old man flagging. If i was going to listen to LCD soundsystem the sohaII woudl be my choice, if norah jones then it would be the bijou. 

 Both amps get a massive thumbs up - and thanks goes to alex.


----------



## amphead

Thank you for taking the time Adamus! While many of us don't have both machines in our stables, we gain some valuable insight with your head to head comparison!


----------



## TimJo

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_For me, the bijou is still the king of the cavalli's, you cant compete with the spaciousness it portrays, but the SohaII is snapping at its heals, and in a sprint leave the old man flagging. If i was going to listen to LCD soundsystem the sohaII woudl be my choice, if norah jones then it would be the bijou._

 

Thanks for the review Adamus. It just helped me confirm that I need to build both of them.


----------



## adamus

no probs chaps. 

 Got to say, i am listening to the sohaII with 8416's in. Its very responsive to tube rolling, the 8416's are lovely.


----------



## smeggy

So I was looking at the Bijou boards _again _and it seems like a pretty simple design with few parts. Death and smoldering corpses aside, is this considered an easy-ish build for a first venture into an all tube amp by an idiot? I'll be making an EHHA in the meantime so this'll be down the road a little. I've never had an all tube amp so figured this is as good as any to get on with (like I need any more DIY projects).


----------



## pabbi1

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_So I was looking at the Bijou boards again and it seems like a pretty simple design with few parts. Death and smoldering corpses aside, is this considered an easy-ish build for a first venture into an all tube amp by an idiot?_

 

I am living proof. Get the psu done right, and there really is very little that can go wrong. Parts selection is the biggest variable.


----------



## smeggy

Cheers, I'd be buying a glass jar kit so won't have to agonize ab out that aspect


----------



## fishski13

adamus,
 kudos for the review.


----------



## ericj

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_So I was looking at the Bijou boards again and it seems like a pretty simple design with few parts. Death and smoldering corpses aside, is this considered an easy-ish build for a first venture into an all tube amp by an idiot? I'll be making an EHHA in the meantime so this'll be down the road a little. I've never had an all tube amp so figured this is as good as any to get on with (like I need any more DIY projects)._

 

It was my first real tube amp and I'm still alive. 

 Just keep one hand in your pocket when there's HV on the boards, observe proper wire twisting and routing, and establish a good star ground and you'll be fine.


----------



## rolotube

Adamus, thanks for the great review. I only have the Bijou at present but you have sparked my interest in looking into a hybrid.

 smeggy, the Bijou is much easier regarding construction than many tube amps & Jeff's kit is comprehensive with good quality parts. I have constructed many tube & SS amps over the years so whilst it wasn't a technical challenge, the enjoyment factor was as good or better than far more complex builds. OTOH, the sound is unquestionably better than ANY of them. I have seen very few amps that exhibit such elegant simplicity & the ways in which some difficult technical challenges of the Futterman design have been overcome (eg. requirement for multiple PS & bias) are extremely neat. 

 IMO, it would be very difficult to find a better tube am design to start with. Go for it.


----------



## smeggy

Thanks guys, looks like I'll be going from no tubes at all, ever, to lots of them in very short order


----------



## balderon

My Bijou casework has taken much longer than expected bit I am nearly completed. I have been saying to myself for weeks... "just one more hole to drill" haha 

 I decided to construct the case using all 2.5mm aluminum alloy (5052-H32). Already the case is quite heavy by itself. I am now wondering if I should of used lighter material on the sides and top? One thing is for certain - it's not going anywhere once I place it on my desk.

 I can finally clean off my desk and heat up my soldering iron!


----------



## fishski13

balderon;5593569 said:
			
		

> I have been saying to myself for weeks... "just one more hole to drill" haha
> 
> 
> > perpetual optimism builds character in the face of failures - at least thats the b.s. i tell myself when i end up throwing tools across the room, cursing mad as hell.
> ...


----------



## funch

Pardon my lack of circuit knowledge, but I need to know if the signal 
 through C1 is going - to + on the schematic, or + to -. I'm going to be 
 replacing C1 with Auricaps, and they are 'directional' (signal going from the
 black lead to the red lead). Thanks.


----------



## runeight

Interesting question. Signal goes from the output to the junction of R5 and R6 which means it goes from + to -.


----------



## funch

So it's involved in feedback?


----------



## runeight

Yes. It is not the normal type of NFB, however.

 This feedback compensates for the fact that the cathode of the upper triode is moving with the O/P signal while the cathode of the lower triode is at a constant voltage (ground).

 C1 feeds back the O/P signal to the phase splitter where it appears immediately at the cathode of the splitter and where it adds itself to the normal signal introduced at the grid of the splitter. This causes the grid drive on the upper triode to be much larger than the grid drive on the lower triode. The larger drive on the upper triode exactly compensates for the fact that the cathode is moving with the signal. 

 The net result is that the grid-to-cathode signal voltages on both triodes are identical ensuring that they are exactly in push-pull balance.

 This was Futterman's invention although I'm not sure that his orignal amps actually employed the technique completely correctly.


----------



## rolotube

"My Bijou casework has taken much longer than expected..........."

 This is the story of my life at present as well. Mine's more practical than flash (Hammond steel rectangular with perforated cover) but still requires a fair amount of design & much drilling. I need more hours in the day.

 Now my Bijou is in bits awaiting the re-build, I got distracted by Adamus's comparo of the Bijou & SOHA II. I've never tried or even properly listened to a hybrid but the concept is very intriguing & the SOHA looks like a good starting point. So I'm going to order a kit from Jeff Rossell. Its about the same price as the basic Bijou kit but includes a transformer & is quite a bit simpler as everything except transformer is on the board. No plans to go overboard with "nice bits" (as with the Bijou) but it will be an enjoyable project & satisfy my curiosity about hybrids.

 runeight, thanks for the explanation about the Futterman feedback cap & finer points of the circuit's operation. I'd searched for such an explanation of how it worked, including going back to some of Futterman's notes, but still couldn't work it out. IMO, its a brilliant design that's still not properly understood or appreciated by many audiophiles.


----------



## SBoy

I've read through 140+ pages before coming to a conclusion to DIY this amp.

 I have some questions though.
 1) Can I use CAT5 cable for all my internal wiring except for the signal cable?
 2) Some of you said something about bleed the high voltage cap. Does it mean run a resistor across the Caps' leg?

 Sorry if i have used the wrong terms, haven't got the time to fully indulge in DIY but i'm getting to it.


----------



## whitelabrat

SBoy - If the CAT5 is rated for 300v or better then it wouldn't hurt to try it. 

 Without modifications the high-voltage caps of the Bijou's power supply should already bleed, perhaps through R9/R10? Not sure exactly.


----------



## whitelabrat

I've been caught up with home repairs and probably won't have any time to do any modifications to my Bijou as I had suggested before. I did take some time last night though and I put in a three position switch so I can select bias for 2.4kohm (6bq7), 2kohm (6922), and 1.5k ohm (6N1P). Nice.

 I'll post the V1 voltage readings later, but the 6bq7 measured about the same as the 6N1P with appropriate bias settings.

 Listening impressions using AKG K240 Monitor headphones, and no major mods to circuit aside from bias. My own opinions may suck so bear with me:

 Valvo PCC88 = yuck. But it's better than nothing. I would expect it would do better with the appropriate 7v heater voltage (7.6v???).
 6N1P-VI = Thick bass, but a bit loose. Kinda reminds me of listening to the neighbor's old console radio in the basement while playing "Santana" and playing pool.
 RCA 6bq7 = Best so far. Detailed and tight. Smooth as butter. Typical RCA blackplate awsomeness.

 I'm curious about 6922 now. The 6922 is an improved 6dj8 which is an improved 6bq7. I can't remember where I read it but hearsay says that the improvments aren't noticeable until you're pushing the current limits of the tubes and it's probably more RF related. So anyway that's my propoganda for the day.

 Someone should publish this thread as a book.


----------



## SBoy

Well.. then i suppose i can't use CAT5 for the internal wiring since 300v would instantly melt it. Can anybody clarify my 2nd question? =)


----------



## pabbi1

The 7308 is an 'even better' 6922 - may want to give them a look, though I don't use them here. I also have 6n23p-ev to try as well, but use them in the Raven with 6h30-DR.

 I kinda like the 6n1p, but also need that switch to change the bias for the different tubes... one day.


----------



## amphead

SBoy, if you are on a shoestring budget, Radio Shack or automotive hookup wire will work. 22ga signal, 22ga HV, 20ga power, 20ga heaters. Welcome to the Bijou Project!

  Quote:


  Originally Posted by *SBoy* /img/forum/go_quote.gif 
_Well.. then i suppose i can't use CAT5 for the internal wiring since 300v would instantly melt it. Can anybody clarify my 2nd question? =)_


----------



## runeight

Quote:


  Originally Posted by *SBoy* /img/forum/go_quote.gif 
_I've read through 140+ pages before coming to a conclusion to DIY this amp.

 I have some questions though.
 1) Can I use CAT5 cable for all my internal wiring except for the signal cable?
 2) Some of you said something about bleed the high voltage cap. Does it mean run a resistor across the Caps' leg?

 Sorry if i have used the wrong terms, haven't got the time to fully indulge in DIY but i'm getting to it. 
	

	
	
		
		

		
		
	


	


_

 

SBoy, nice to see another Bijou Builder.

 1. As mentioned, ethernet cable is not good for HV wiring. Use wire with at least 600V insulation stand off.

 2. If you need to debug the PS then you should discharge across the output of the PS using a 100k 1W resistor before you start poking around. If you don't you might get a nasty shock. And if you short the PS when it is fully charged you will wipe out the mosfets.

 Good luck.


----------



## SBoy

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_SBoy, nice to see another Bijou Builder.

 1. As mentioned, ethernet cable is not good for HV wiring. Use wire with at least 600V insulation stand off.

 2. If you need to debug the PS then you should discharge across the output of the PS using a 100k 1W resistor before you start poking around. If you don't you might get a nasty shock. And if you short the PS when it is fully charged you will wipe out the mosfets.

 Good luck. 
	

	
	
		
		

		
			



_

 

Oh. thanks for the info. One problem though, Jeff Rossel hasn't reply my email for a week already. any ideas what he is up to?


----------



## naamanf

Quote:


  Originally Posted by *SBoy* /img/forum/go_quote.gif 
_Oh. thanks for the info. One problem though, Jeff Rossel hasn't reply my email for a week already. any ideas what he is up to?_

 

I hear he is hunting for wolverines in Alaska. 

 I am just about about done with my Bijou (after having all the parts for over a year) so stay tuned. And I can verify that shorting the PS will kill the MOSFETS
	

	
	
		
		

		
		
	


	




 Be very careful with your MM leads


----------



## amphead

Thats awesome man! Will you bring the Bijou to CanJam?


----------



## smeggy

I wanna build one too after the EHHA and maybe a M^3. Let us know how the build progresses as I'm not having any luck with Jeff either.

 I was hoping to already have the EHHA built by now


----------



## naamanf

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Thats awesome man! Will you bring the Bijou to CanJam? _

 

Me? 

 If nobody else is and someone wants to put it on their table I could be persuaded. That's if I don't do anything else stupid with me test leads.


----------



## SBoy

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_I hear he is hunting for wolverines in Alaska. 

 I am just about about done with my Bijou (after having all the parts for over a year) so stay tuned. And I can verify that shorting the PS will kill the MOSFETS
	

	
	
		
		

		
		
	


	




 Be very careful with your MM leads 
	

	
	
		
		

		
		
	


	


_

 


 Oh yes, i'll be careful. This reminds me the time i killed a couple of mosfets when i shorted my CK2III amp.


----------



## SBoy

Well, let's wait for him to come back


----------



## naamanf

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_I wanna build one too after the EHHA and maybe a M^3. Let us know how the build progresses as I'm not having any luck with Jeff either.

 I was hoping to already have the EHHA built by now 
	

	
	
		
		

		
		
	


	


_

 

Populating the boards is the easy part. Casing and wiring it all up is what takes all the time and effort. Seems to be the case with most builds.


----------



## smeggy

Damn Wolverines!!


----------



## sachu

Is anyone taking an EHHA with them to CanJam...

 If not, I might be willing to ship mine down there..if I can get it done soon


----------



## smeggy

That'd be cool, might get more interest going.


----------



## sachu

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_That'd be cool, might get more interest going._

 

Hell yeah..this is one amp taht is worth building..even more so than the Bijou or the Soha 2..I won't go so far as to say better than the Stacker..but its up there.


----------



## SBoy

Quote:


  Originally Posted by *sachu* /img/forum/go_quote.gif 
_Hell yeah..this is one amp taht is worth building..even more so than the Bijou or the Soha 2..I won't go so far as to say better than the Stacker..but its up there._

 

Oh. Now you got me thinking whether to change my DIY plans or not


----------



## SBoy

Quote:


  Originally Posted by *sachu* /img/forum/go_quote.gif 
_Hell yeah..this is one amp taht is worth building..even more so than the Bijou or the Soha 2..I won't go so far as to say better than the Stacker..but its up there._

 

I saw u have a CTH build. I'm curious where you got your "ring" from? The circle thing that go around the tube. What is that called guys?


----------



## Forte

Quote:


  Originally Posted by *SBoy* /img/forum/go_quote.gif 
_I saw u have a CTH build. I'm curious where you got your "ring" from? The circle thing that go around the tube. What is that called guys?_

 

Its one ring of a Tube Protector, there are normally three rings which form a cage to protect the tube. Available from Audio Catalog or on eBay.


----------



## SBoy

OH now i understand!! we could have just use one ring instead of three rings. No wonder it looks so familiar but i googled and can't find it. Thanks alot.


----------



## pabbi1

Since no one else has a balanced Bijou (all apologies to Fishski), I'll ship mine to CanJam for _someone_ to set up, assuming I don't go, but my dilemna is that it, the Raven (idht in my sig), the Vulcan (new stat amp) and the Poor Man's (if we get that done) also need to be there. Add a source, phones and cables, and I'm shipping 300 lbs without the Blue Hawaii... <sigh>.

 But, gotta get it all built and cased, but Bijou is ready to roll. Prayer will be required, and not just for getting it all there, and back.


----------



## naamanf

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Since no one else has a balanced Bijou (all apologies to Fishski), I'll ship mine to CanJam for _someone_ to set up, assuming I don't go, but my dilemna is that it, the Raven (idht in my sig), the Vulcan (new stat amp) and the Poor Man's (if we get that done) also need to be there. Add a source, phones and cables, and I'm shipping 300 lbs without the Blue Hawaii... <sigh>.

 But, gotta get it all built and cased, but Bijou is ready to roll. Prayer will be required, and not just for getting it all there, and back._

 

I should be there and can help out wherever needed.


----------



## naamanf

Teaser pic...


----------



## pabbi1

I might need to recase the Bijou, but you whipping my ass about it won't make it happen any sooner...  The tiger maple is a nice choice - very Euro like.

 Curious what you think about it once finished - and, what tubes are you using. Edit: And, how you treated the bottom, especially how you are mounting the tranny.


----------



## bhjazz

I just came across ludoo's MegaThread page for Head Fi and asked him if he coud do one for this 167-page monster (the Bijou thread). It's done, and pretty cool. All indexed by ludoo. I like it! Check it out -> Home / Head-Fi Megathreads


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Since no one else has a balanced Bijou (all apologies to Fishski), I'll ship mine to CanJam for _someone_ to set up, assuming I don't go, but my dilemna is that it, the Raven (idht in my sig), the Vulcan (new stat amp) and the Poor Man's (if we get that done) also need to be there. Add a source, phones and cables, and I'm shipping 300 lbs without the Blue Hawaii... <sigh>.

 But, gotta get it all built and cased, but Bijou is ready to roll. Prayer will be required, and not just for getting it all there, and back._

 

no apologies needed 
	

	
	
		
		

		
		
	


	




. i'd be willing to send my SE Bijou with Mundorf outcaps...if i actually had the time to re-build it. now that i'm done with the HO guitar amp, i just need to finish the Gainclone and CK2III/pre-amp with on-board gamma-1. everythings soldered up - just need to do the chassis work.


----------



## amphead

That Tiger Maple is gorgeous! Yeah it would be nice to have a balanced Bijou at CanJam. I still remember the golden flutter of sound.

 Here is a pic of my prototype called the UVA or Universal Volume Assembly. It features a 58x21mm stainless knob rotating on 1/2" stainless shaft through a precision bearing mount. I'm building a few for the show.....


----------



## smeggy

those things look awesome!


----------



## TimmyMac

How tall is your amp enclosure? I know my B22 with a 3" height looks a little goofy with just a 50mm dia flange on my volume knob. My 2.5" Bijou would barely even hold that!


----------



## amphead

The UVA is intended for any of the taller amps, say 3.5" to about 8 inches. And those I consider to be more of a vintage Marantz look. The UVA gives an indestructible and butter-smooth feel, with a bit of a weighty feel. I will eventually, have some 42mm stainless knobs with 6mm mounting holes, to mount directly onto the pot shaft for smaller sized amps, but not till after the CanJam show. Later on, I will be using the AMP brand name(Audio Machinist Products), but not yet. Edit: the UVA should probably have an illuminated ring around the knob, and a shroud assembly that covers the mounting plate.


----------



## naamanf

She lives!





 I just have some hum on the right side I need to figure out now.

 And finish the top.


----------



## naamanf

Double post and stuff.


----------



## smeggy

Dammit Naaman, I hate you!!


----------



## MoodySteve

That is very, very nice looking. Well done!!


----------



## Listen2this1

naamanf That looks great, nice choice of wood and finish work. Any pics from the top. I would like to see the inside, and what power transformer is that?


----------



## naamanf

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_Dammit Naaman, I hate you!!





_

 





  Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_That is very, very nice looking. Well done!! 
	

	
	
		
		

		
		
	


	


_

 

Thanks. And it's sounding pretty good now too. There was a buzzing in the right side which turned out to be an extra 22v A/C relative to ground on one set of heater leads. Put it all on the other set and it's all quiet. 

 Started with a set of Sylvania 6DJ8s. Moved on to a pair of Amperex PQ 7308. Much better.


----------



## naamanf

Quote:


  Originally Posted by *Listen2this1* /img/forum/go_quote.gif 
_naamanf That looks great, nice choice of wood and finish work. Any pics from the top. I would like to see the inside, and what power transformer is that?_

 






 The transformer is the R80-36. I don't think I would get it again. Hammond all the way.


----------



## smeggy

That wood is beautiful, you must have a great wood supplier nearby. The insides, impeccable as always.


----------



## holland

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_The transformer is the R80-36. I don't think I would get it again._

 

I'm curious what you find faulty about the R80-36? I have that same one on my Bijou (which remains idle still).


----------



## funch

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_She lives!





 I just have some hum on the right side I need to figure out now.

 And finish the top._

 

I also have a very faint hum in the right channel.

 Is your right channel board the one closest to the power button, 
 just in front of the tranny?


----------



## Forte

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_The transformer is the R80-36. I don't think I would get it again. Hammond all the way._

 

What don't you like about the R-core transformer? I have one here for my build once I can find a suitable enclosure.


----------



## naamanf

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_That wood is beautiful, you must have a great wood supplier nearby. The insides, impeccable as always._

 

I just visit my local Woodcraft now and again. If I see some thing I like I pick it up for future use.
  Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_I'm curious what you find faulty about the R80-36? I have that same one on my Bijou (which remains idle still)._

 

It has extra taps and windings that are not used. I would rather have something that only has what is going to be used. The real kicker is having the one set of bad heater windings. Well it's either bad or I am overlooking something stupid. 

  Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_I also have a very faint hum in the right channel.

 Is your right channel board the one closest to the power button, 
 just in front of the tranny?_

 

That is the right channel board. Once I put all the heaters on the good winding problem solved.


----------



## amphead

Nice layout as you have done on other projects. CanJam is going to be a winner. 
 I'm still working on an illuminated ring and shroud for the volume assembly.


----------



## naamanf

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I'm still working on an illuminated ring and shroud for the volume assembly._

 

I almost went that route but decided to keep it simple. I bet having a lathe comes in handy


----------



## SBoy

It's been a week plus since i last emailed Jeff and he still hasn't reply my email. Is it this normal or should i send him another email?


----------



## bhjazz

Quote:


  Originally Posted by *SBoy* /img/forum/go_quote.gif 
_It's been a week plus since i last emailed Jeff and he still hasn't reply my email. Is it this normal or should i send him another email?_

 

Yes, that's pretty normal for Jeff. You might shoot him another.


----------



## AudioCats

Just in case anybody might be interested (this is the Bijou thread after all), I have a set of 4 PCB's (two amp board two PS board) for sale. 

 Mean while, my Bijou is still not yet completed


----------



## balderon

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Here is a pic of my prototype called the UVA or Universal Volume Assembly. It features a 58x21mm stainless knob rotating on 1/2" stainless shaft through a precision bearing mount. I'm building a few for the show.....
http://i207.photobucket.com/albums/b...lessfront2.jpg_

 

I like the look amphead! I am planning on using heavy knobs on my Bijou and I am concerned about the stresses on the pot. May I ask where you are obtaining the bearings and how they are mounted?

 I have finally heated up my soldering iron and finished the power supply. One of the channels is nearly complete. I am having a much better time with the electronics than the mechanical. It's embarrassing to say that I built the height of my case a little shorter than required. The Hammond 370DAX extends about 1/16 inch above the top cover 
	

	
	
		
		

		
		
	


	




 I didn't want to relocate the tranfo plus I didn't really need the additional windings on the primary so I decided to purchase the slightly shorter 270DAX. 

 Please PM me if anyone is interested in a bargain for a 370DAX! I have modified the exit points of the primary and secondary wiring by re-routing the wires to exit the shroud on the sides instead of the bottom. No electrical modifications have been done.


----------



## chobint

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_She lives!





 I just have some hum on the right side I need to figure out now.

 And finish the top._

 

So I guess head-fi doesn't like to send your subscriptions anymore when you just lurk and don't post, so here's my periodic post : D

 That wooden case looks really great. I think it's pretty impressive to note how many poorly shielded Bijou's are very quiet. I bunch of people noted at the last meet how quiet my Bijou is despite its relatively poor shielding. It seems from naamanf's comments that his is also quiet, which makes me wonder...

 Are tube amps notoriously difficult to get quiet because of internal interference (heaters, etc) or b/c of outside interference from RF? or perhaps a totally different reason altogether


----------



## amphead

Thanks, the bearing is a precision bearing 1/2" inside diameter and 1.125" outside diameter. There is an aluminum backing plate which is drilled for 1.125", where the bearing is installed with epoxy and I have a stainless top plate drilled for the diameter of the inside race of the bearing. With a delrin washer on the 1/2" shaft held in place with a 1/2" steel collar. This allows the knob to float on the shaft/bearing housing for a butter-smooth feel. The bearing can be any "precision" bearing with ID and OD the same as what I have used. There is a brass coupler that I manufactured on the lathe that goes from 1/2" shaft to 6mm pot shaft. The picture doesn't show the blue-green illuminated ring and polished ebony shroud that I'm building at the moment. Then the ugly mounting back plate won't show. Edit: the bearing was obtained from "Grainger", but googling will give many sources.

  Quote:


 I like the look amphead! I am planning on using heavy knobs on my Bijou and I am concerned about the stresses on the pot. May I ask where you are obtaining the bearings and how they are mounted?


----------



## TimmyMac

Use a skateboard bearing. They're cheap and have 8mm ID that you can easily shim to 1/4" for use with pot shaft extensions.


----------



## naamanf

Boca Bearings :: Miniature Bearings for Hobby and Industry :: Steel and Ceramic Bearings


----------



## holland

would it be ok to add bleeder resistors to the PSU caps? If so, what values?


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Are tube amps notoriously difficult to get quiet because of internal interference (heaters, etc) or b/c of outside interference from RF? or perhaps a totally different reason altogether_

 

i wonder too. i actually had been thinking a lot about this when building a SE High Octane EL84 guitar amp. it seemed like a lot of people have noise problems with this particular type of circuit lay-out implemented in the design, despite using significant amounts of shielded wiring. i decided to modify the lay-out and run DC heaters, and shielding only the single input wire to the first gain stage. zero noise issues.

 i'm having difficulty coming up with a "reasonable" chassis size for my Bijou re-build with the large film output caps. i think i may run DC heaters so that i can cinch up the chassis size a bit.


----------



## balderon

Thanks amphead for the help. I have a backing plate behind my front panel. I think I might be able to use this plate to secure the bearings. Thanks naamanf and TimmyMac for the info.


----------



## chobint

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i'm having difficulty coming up with a "reasonable" chassis size for my Bijou re-build with the large film output caps. i think i may run DC heaters so that i can cinch up the chassis size a bit._

 

Could follow ferrari's lead and mount them externally. Would be a shame to keep those beautiful things hidden away inside the case


----------



## breizheau

Hi there,
 i received my customized transfos made by my favourite french company. They are huge and nice. 
	

	
	
		
		

		
		
	


	



 Specs : 
 - primary : 230V
 - secondary 1 : 260-0-260 @ 200mA
 - secondary 2 : 0-6.3 @ 4A

 I hope it's enough ! 
	

	
	
		
		

		
		
	


	




 i have 2 like this because i am building a balanced Bijou. I hope to start the soldering tomorrow. 
	

	
	
		
		

		
		
	


	




 I can't wait to listen to it.... 
	

	
	
		
		

		
		
	


	




 I still have to draw the design of the casing.


----------



## pabbi1

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_





 Thanks. And it's sounding pretty good now too. There was a buzzing in the right side which turned out to be an extra 22v A/C relative to ground on one set of heater leads. Put it all on the other set and it's all quiet. 

 Started with a set of Sylvania 6DJ8s. Moved on to a pair of Amperex PQ 7308. Much better._

 

Any further impressions? Gonna share the balanced tonight with Marc & Steve (the OrthoDynamic Duo), and see what they think - well, if we don't just DIY the whole time. And, I'll have the SOHA II along as a punching bag... er, comparative data point, even if it is SE.


----------



## breizheau

I have started to solder the amp components. The kit sold by glassjaraudio is pretty nice....


----------



## amphead

Yes, Jeff is the man when it comes to kits. Great to hear that you are starting your build. I am still working on the volume assemblies between projects.


----------



## rolotube

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i wonder too. i actually had been thinking a lot about this when building a SE High Octane EL84 guitar amp. it seemed like a lot of people have noise problems with this particular type of circuit lay-out implemented in the design, despite using significant amounts of shielded wiring. i decided to modify the lay-out and run DC heaters, and shielding only the single input wire to the first gain stage. zero noise issues.

 i'm having difficulty coming up with a "reasonable" chassis size for my Bijou re-build with the large film output caps. i think i may run DC heaters so that i can cinch up the chassis size a bit._

 

fishki
 Just finished a rebuild of my heavily modded Bijou, including a full complement of Mundorf Tubecaps, which take up lots of room. Not having the time or resources to construct a fully custom chassis/case from scratch, I went for a couple of Hammond chassis #1441-22BK3 & perforated covers #1451-22BK3. These aren't flash but provide functional & durable housings for the amp & power supply. Being steel, they also provide a measure of shielding, so long as sound earthing procedures are followed. Which brings me to the other issue you discuss - noise. I'm running a 370 DAX, EZ81 (6CA4), amphead's heater mods, & no shielded cable anywhere. The amp is dead silent - black as night - at least as quiet as any mains, or even battery powered, SS amp I've built. I would not have believed this was possible using AC heaters & one of my first reactions when I decided to build the Bijou was how could I convert the heaters to DC. But the level of silence is such that I could not possibly HEAR anything quieter, let alone imagine it, so any advantage DC heaters may provide would be perceived rather than actual. I'm not entirely sure why this should be so, but the separate amp & PS chassis together with careful attention to proper star grounding probably has much to do with it.

 As for the sound - I haven't heard anything that comes close. Its only after a few weeks of listening to other amps, then coming back to the Bijou, that I realise just how good it is.

 I'll post some photos of the new build shortly.


----------



## breizheau

This an idea of my final bijou. It seems it's not so difficult to do.


----------



## swt61

Quote:


  Originally Posted by *naamanf* /img/forum/go_quote.gif 
_She lives!





 I just have some hum on the right side I need to figure out now.

 And finish the top._

 

Really nicely done Namaan!


----------



## breizheau

Nice work ! The challenge is good...


----------



## Proutch

Hi all,

 I received the Bijou kit from Jeff a couple of days ago, and I'll start soldering next weekend 
	

	
	
		
		

		
			




 First of all, I want to thank all of you (Amphead, Adamus, Ferrari and others) for the incredibly useful information you shared in this forum. This was very useful to prepare, and also very inspiring. 
	

	
	
		
		

		
		
	


	



 I had a hard time deciding about the case. I finally chose a 230mmx230mm Hifi200 Galaxy. It might be a challenge to fit everything in it, but I wanted something as small as possible.

 I'm experienced in tube DIY (I built one of these), but not in audiophile stuff, so I have a couple of questions.

 I'll replace C2 with SILMIC II ELNA cap and C6 with Mundorf MCAP.
 C5 will remain Jeff's part, since I haven't found the right value/money compromise yet. Any suggestion here?

 I have a last concern with cable. I'm about to take silver plated single strand wire, PTFE coated - 18 awg for heaters, 22 for the rest. See here
 What do you think? Is that an acceptable choice?

 I'll keep you posted 
	

	
	
		
		

		
		
	


	




 Thanks again, guys!


----------



## naamanf

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_
 I'll replace C2 with SILMIC II ELNA cap and C6 with Mundorf MCAP.
 C5 will remain Jeff's part, since I haven't found the right value/money compromise yet. Any suggestion here?

 I have a last concern with cable. I'm about to take silver plated single strand wire, PTFE coated - 18 awg for heaters, 22 for the rest. See here
 What do you think? Is that an acceptable choice?
_

 

A lot of people have had good luck with photo caps for C5. And they don't break the bank. 

 That wire should work fine but seems a bit pricey to be using for hook-up wire. IMHO.


----------



## pabbi1

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_Hi all,

 I'll replace C2 with SILMIC II ELNA cap and C6 with Mundorf MCAP.
 C5 will remain Jeff's part, since I haven't found the right value/money compromise yet. Any suggestion here?

 I have a last concern with cable. I'm about to take silver plated single strand wire, PTFE coated - 18 awg for heaters, 22 for the rest. See here
 What do you think? Is that an acceptable choice?_

 

Send me a PM, and I'll send you some of the photoflash caps. 

 The wire looks fine, and those are the values I use for heater and signal - just didn't see a temp value. 600v minimum, 105c is good and 200c is better - overkill, but best in case of archy-sparky.

 Naaman, thoughts on the sound?


----------



## naamanf

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Send me a PM, and I'll send you some of the photoflash caps. 


 Naaman, thoughts on the sound? 
	

	
	
		
		

		
		
	


	


_

 

Al's good on caps 
	

	
	
		
		

		
		
	


	




 I claim to be a member of team lead ears, but hmm.....the words I would use are alive, punchy, and vibrant. My reviews fit in three catagories. I like it, it's okay, and meh. It's in "I like it" territory.


----------



## rolotube

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_Hi all,

 I received the Bijou kit from Jeff a couple of days ago, and I'll start soldering next weekend 
	

	
	
		
		

		
		
	


	



 First of all, I want to thank all of you (Amphead, Adamus, Ferrari and others) for the incredibly useful information you shared in this forum. This was very useful to prepare, and also very inspiring. 
	

	
	
		
		

		
		
	


	



 I had a hard time deciding about the case. I finally chose a 230mmx230mm Hifi200 Galaxy. It might be a challenge to fit everything in it, but I wanted something as small as possible.

 I'm experienced in tube DIY (I built one of these), but not in audiophile stuff, so I have a couple of questions.

 I'll replace C2 with SILMIC II ELNA cap and C6 with Mundorf MCAP.
 C5 will remain Jeff's part, since I haven't found the right value/money compromise yet. Any suggestion here?

 I have a last concern with cable. I'm about to take silver plated single strand wire, PTFE coated - 18 awg for heaters, 22 for the rest. See here
 What do you think? Is that an acceptable choice?

 I'll keep you posted 
	

	
	
		
		

		
		
	


	




 Thanks again, guys!_

 

My 5 cents worth...........

 The kit C2 (Panasonic) is a reasonable cap but the SILMIC should be better. Whether you'd hear the difference is a moot point. I have some Blackgate FK & NX as well as Cerafine's to replace C2, but haven't done anything as yet. Its on the to do list.

 C6 - I initially tried a Jupiter 1uF 600V paper/beeswax (solid Ag leads) & this was a huge improvement, but I found the bass still a bit too prominent for my taste. If you intend to keep C6 as an electro, my suggestion is to get the best cap for C6 you can afford. It seems to matter. IMO, Jupiter is a very underrated cap, but a search of this thread will show others have been used successfully as well.

 C5 - I'm now running a Mundorf Tubecap 200uF 600V, no bypass. This has tightened up the sound significantly, but bass is still deep & sustained. WTG, IMO.

 C1 is also a very important cap & may benefit from an upgrade. I'm using an MCap (15uf) with good results. See previous posts as well as feedback from Alex re this.

 Hookup - I used Welborne silver plated stranded PTFE in the gauges you specify for heaters & HV. Its one of the best wires I've used. All signal wiring is Jupiter 23 & 28G solid 4N Ag cotton covered. This is also beautiful stuff to work with & won't get in the way of the music.


----------



## Proutch

Thanks a lot for your (super fast) replies 

 I was uncertain whether C2 would really matter, but I'll definitely take a look at previous posts for C1 options
 Thanks also for your advice about wires - I guess the one I found are a decent option, so I'll take those (even if it's not deal of the century)

 And last but not least, photoflash caps look like a great option - and not to pricey...
 Pabby, you're offer is much appreciated. Youv'e got a PM 
	

	
	
		
		

		
		
	


	





 Thanks again guys, your help is awesome


----------



## fishski13

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_fishki
 Just finished a rebuild of my heavily modded Bijou, including a full complement of Mundorf Tubecaps, which take up lots of room. Not having the time or resources to construct a fully custom chassis/case from scratch, I went for a couple of Hammond chassis #1441-22BK3 & perforated covers #1451-22BK3. These aren't flash but provide functional & durable housings for the amp & power supply. Being steel, they also provide a measure of shielding, so long as sound earthing procedures are followed. Which brings me to the other issue you discuss - noise. I'm running a 370 DAX, EZ81 (6CA4), amphead's heater mods, & no shielded cable anywhere. The amp is dead silent - black as night - at least as quiet as any mains, or even battery powered, SS amp I've built. I would not have believed this was possible using AC heaters & one of my first reactions when I decided to build the Bijou was how could I convert the heaters to DC. But the level of silence is such that I could not possibly HEAR anything quieter, let alone imagine it, so any advantage DC heaters may provide would be perceived rather than actual. I'm not entirely sure why this should be so, but the separate amp & PS chassis together with careful attention to proper star grounding probably has much to do with it.

 As for the sound - I haven't heard anything that comes close. Its only after a few weeks of listening to other amps, then coming back to the Bijou, that I realise just how good it is.

 I'll post some photos of the new build shortly._

 


 cool. thanks...good to know!!! i think the decision for DC heaters will primarily depend on the P2P wiring lay-out i finally decide on. if it ends up too much bigger than the PCBs, i'll stick with the PCB - besides, they're already done, silent, and operational. 

 a bridge rectifier with some caps doesn't take up a whole lot of room and is maybe $10 in parts: see pic for the guitar amp i built with homebrewed aluminum plate at 1.25" x 2.75. 

 since i'm DIYing the chassis, i have some flexibility. but jeeez, DIYing your own chassis can be a lot of work.


----------



## sachu

wow is that your star ground ? The one with all the hex nuts?..damn!


----------



## fishski13

Quote:


  Originally Posted by *sachu* /img/forum/go_quote.gif 
_wow is that your star ground ? The one with all the hex nuts?..damn! 
	

	
	
		
		

		
		
	


	


_

 

yup, multiple gain stages without "intermediate", isolated ground-stars.


----------



## rolotube

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_cool. thanks...good to know!!! i think the decision for DC heaters will primarily depend on the P2P wiring lay-out i finally decide on. if it ends up too much bigger than the PCBs, i'll stick with the PCB - besides, they're already done, silent, and operational. 

 a bridge rectifier with some caps doesn't take up a whole lot of room and is maybe $10 in parts: see pic for the guitar amp i built with homebrewed aluminum plate at 1.25" x 2.75. 

 since i'm DIYing the chassis, i have some flexibility. but jeeez, DIYing your own chassis can be a lot of work._

 

I didn't realise you were doing P2P. My comments above were in the broad context of the "kit" Bijou plus or minus some mods, but still using the PCB's & same basic layout. If you've got the space in a P2P build, I'd definitely recommend try DC. Theoretically, it should be significantly quieter with no high current AC fields floating around.

 A DIY chassis is the ideal & can really show off a great build (consider what's been posted here just lately). I'll be interested to see the results of your labors.


----------



## funch

NVM.


----------



## amphead

Yeah the Bijou can be built quiet with AC heaters. Happy to see others having success. Still working on and off to get volume assemblies finished.


----------



## dBel84

so u ever going to finish building this thing or is the mill too much fun in its own right 
	

	
	
		
		

		
		
	


	




 ..dB


----------



## amphead

I'm jumping through hoops to have 2 finished by CanJam. Here is a recent distraction however........
	

	
	
		
		

		
		
	


	




 Eye candy to support more ear candy.

Laser Pointer Forums - Discuss Lasers & Laser Pointers


----------



## holland

It's been a long time in the making. Sadly to report it's been sitting on a shelf for a year, incomplete. Anyhow, it's mostly done now. I need to drill the NABU cover.

 My B+ is sagging to 245V with the regulator at max output. 
	

	
	
		
		

		
		
	


	




 I'm running the Regal mod (6DJ8, 6N6Pi, EZ81) with PP caps and the feedback version with feedback at minimum. It's a PITA to remove the resistors, so I may remove the pot and put in a 1M feedback resistor. No noise so far. Volume knob has very good movement with the feedback at minimum.

 My heater voltage is a bit high @ 6.9V, I need to increase the resistor.

 I know I need to vacuum, but I just finished all the wiring.


----------



## adamus

looking good holland! 

 you could try the ecc99's in place of the 6n6ps - which are have been known to cause the extra draw you're experiencing.


----------



## holland

Thanks adamus. I don't have ecc99. 
	

	
	
		
		

		
			





 I'll probably just run it @ 245v.


----------



## balderon

I am looking for preferably a USA source for (2) 330uF Mundorf M-CAP MKP capacitors. I have Googled with several different search terms without success. Any suggestions?


----------



## pabbi1

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I am looking for preferably a USA source for (2) 330uF Mundorf M-CAP MKP capacitors. I have Googled with several different search terms without success. Any suggestions?_

 

Maxwell Audio? Not sure f he is all eBay, or not.


----------



## balderon

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Maxwell Audio? Not sure f he is all eBay, or not._

 

Thanks pabbi1. That was my first try... but no luck. Largest was 33uF.


----------



## pabbi1

Well, times like this call for PcX... or so how I would proceed.


----------



## rolotube

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Maxwell Audio? Not sure f he is all eBay, or not._

 

PcX have them listed, but at $161.84 each, you'd have to want them real bad......


----------



## balderon

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Well, times like this call for PcX... or so how I would proceed._

 

 Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_PcX have them listed, but at $161.84 each, you'd have to want them real bad......_

 

I have barely 20 hours after the initial power-up of my Bijou. I hope to hear much greater improvements as the components start to break-in. If not I might end up replacing C5 with a MKP and removing C6.

 I appreciate the help.


----------



## adamus

I dont remeber any significant burn in for my bijou. 

 The single greatest improvement i made was to put in some amperex bugle boys (6dj8). really good improvement. It a superb amp with them, easily showing the darkvoice 336i (the only amp i had to compare at the time) a very clean pair of heels.


----------



## rolotube

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I have barely 20 hours after the initial power-up of my Bijou. I hope to hear much greater improvements as the components start to break-in. If not I might end up replacing C5 with a MKP and removing C6.

 I appreciate the help._

 


 Break in has been a less than overwhelming experience with my build. Changes over maybe 50 hours have been definite, but subtle. Much greater effects were obtained instantly by changing components (caps & tubes). But every build is different & what one experiences won't necessarily be experienced by others. I'm running a 200uF Mundorf Tubecap for C5 now (no C6) but I don't think the the difference between replacing C5 with a film cap was as pronounced as retaining the stock electro for C5 & using a high quality cap for C6. I used a Jupiter 1uF paper/beeswax to bypass the 470uF electro. This was a superb improvement over the stock C6 - IMO, Jupiter are greatly underrated caps. But the bass was still a bit too prominent with my HD650's. Tubecaps tightened up the entire sound, but the trade off is slightly diminished bass extension. Not really a major issue for the Senns, which have a rather full bottom end. A 330uF MKP may restore most/all of the bass extension truncated by the Tubecaps, but its not a cost effective improvement (330's are twice the price of 200's) unless your cans are severely bass challenged. In summary, my suggestion would be to keep C5 & get the best C6 you can afford. Almost as good for a lot less money.

 Apologies if I've hammered this point.


----------



## pabbi1

I had so much tube noise on the 6n1p and 6n6p for the first 50 hours that I really never could tell anything else was changing. But, since then, no changes - stability is a good thing. Generally, the Bijou is too bassy for my tastes on the hd650, hence the hd600 - just right.


----------



## holland

^ what pabbi1 said. Unfortunately I went the other way, my Amperex 6DJ8 has developed a "crackling" on one channel that follows the tube. 
	

	
	
		
		

		
		
	


	




 I have resorted to EH 6922s now, which are quiet but now I hear a buzz. I have to hunt a buzz that I have not heard before, but may be related to flourescent lights.

 The break-in of components should be fairly low sans the tube, though I understand MKP takes longer (I have all MKP for my output with 330uF + 150uF). I can experiment with a lytic bypassed with an MKP.

 Funny that you guys find the bass too much. I find the lowest bass not as punchy as I'm used to (SS or hybrid). It definitely has the tube characteristics that I recall from long ago (since it's an all tube amp). It has warmth though, perhaps that's what you are referring to?

 I recall discussions in the past about the 6N1P not operating in a good spot, and having something like 500mV or 900mV cathode bias only, which can result in clipping? Is that still the case, or do the new cathode resistor values rectify that? I do need to try some 6N1P. Less warmth, and more punch would be good for me.


----------



## pabbi1

Since I am balanced, and the attenuator / NFB juggle means I can't listen above 11 o'clock, there is just no chance for clipping, at least not that I have ever heard. The punch with the 6n1p and 6n6p is great for me, even without the hd650 hump. With the faster slew rate, the 'warmth' isn't what others might be getting, especially on the bass. Source might also have something to do with this.


----------



## luvdunhill

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Funny that you guys find the bass too much. I find the lowest bass not as punchy as I'm used to (SS or hybrid)._

 

I could see this being true from listening to Al's via the K1000 and trying to drown out cries for DIY help


----------



## pabbi1

And, with dang near enough output to really drive k1000... but, Marc, how did it sound? That is what everyone wants to know... and, since I am already another dynamic amp down the road...


----------



## fishski13

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_I have to hunt a buzz that I have not heard before, but may be related to flourescent lights._

 

with, or without the top-plate of the NABU? it could just be RFI. all of my projects are noisy on my workbench until i case them completely up.


----------



## whitelabrat

I found that I was getting some buzz too, not from the Bijou but from my CD player's power supply. Most of that went away once I buttoned up the metal case which improves EMI sensitivity. I finally figured out that the feedback goes a long way to squish out power line noise too. With 100 ohm headphones it helps a lot. Even in my office where power is very dirty, the Bijou is dead quiet.


----------



## luvdunhill

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_And, with dang near enough output to really drive k1000... but, Marc, how did it sound? That is what everyone wants to know... and, since I am already another dynamic amp down the road..._

 

geez, tough to say. Typical meet conditions were probably better that this particular listening session. I'd be tempted to roll tubes and see how much the sound signature can change, as it's hard to grade the "amp" versus the "tube compliment". I was just echoing the above comments, as they jived with me. Fast sounding, for an all tube amp, but compared to hybrid amps (even the SOHA II, which I was immediately wowed by) it's not as nimble sounding. Sometimes people call this warm sounding, but to me it sounds slow.. I dunno how to describe it. The bass is definitely there, but there is some bloom or widening at the lower octaves. Soundstaging is top notch, as is the midrange. I prefer the added sparkle solid state seems to give on the upper register (2000 Hz and above) though, but this is no secret. I found things very quiet with a black background. The K1000 seems to be a good pairing with this amp, as it dishes out power in spades.

 I suppose I need to listen to it some more, and dive into my tube stash and see what I can find


----------



## holland

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_with, or without the top-plate of the NABU? it could just be RFI. all of my projects are noisy on my workbench until i case them completely up._

 

With. It's related to my source, volume affects it. Unplugging and it goes silent. It may be a ground loop, or that my lines (power and audio) run very close to the power lines of a flourescent light. I will need to experiment when I get time.


----------



## holland

Quote:


  Originally Posted by *luvdunhill* /img/forum/go_quote.gif 
_Fast sounding, for an all tube amp, but compared to hybrid amps (even the SOHA II, which I was immediately wowed by) it's not as nimble sounding. Sometimes people call this warm sounding, but to me it sounds slow.. I dunno how to describe it. The bass is definitely there, but there is some bloom or widening at the lower octaves. Soundstaging is top notch, as is the midrange. I prefer the added sparkle solid state seems to give on the upper register (2000 Hz and above) though, but this is no secret. I found things very quiet with a black background._

 

x2, really.

 I'm using the 6N1P now. It's less tubby, cooler and more forward. Bass impact is not quite there, still soft, though. Unfocused is a different interpretation of it, though I think it's just not there in the lowest of the lows, not too sure. I need more time with it. It may be just the way it is. I have to claim my bias. I've never heard an all tube amp "do it" for me. The rest is great, as noted. Soundstage, midrange in particular, as noted by all. A bit more on the edges is needed...SS like, which I know this amp isn't SS. 
	

	
	
		
		

		
		
	


	




 I also need more time for the caps to fully form.

 To be honest, it does well with the D2000 as well. The highs are not as sibilant, it's rounder and the D2000 itself supplies enough impact to cover any weaknesses. My DT990, which I love more than the D2000, mates well also. I'll break out the Senns in time. I have to work it through it's paces on each different headphone.


----------



## mugdecoffee

Just finished my Bijou from JRossel's kit and am pretty impressed. The soundstage and separation are excellent. This is an upgrade from a MHSS/mini3. Right now its hooked up to a pair of akg 240 sextetts (MP, recabled) and think the cans are the limiting factor right now.

 For a case I went to goodwill and found an old tape player, took it home, and gutted it. For a faceplate I cut out a piece of wood from an old shelf. Overall, the case cost $6 plus maybe $20 worth of screws and mounting hardware. I ended up paying only about $270 total for the entire project, significantly less than most estimates.

 The building process was easy enough. I got hung up originally trying to wire the heaters. I realized after a bit that the glass jar kit includes 6N6Pi tubes (or ones with the same pins) so I corrected the wiring. Originally I mounted the capacitors under the board so I could mount the boards on top of the case and have the tubes stick out but the boards seemed to heavy for the thinnish top and the PSU board was mounted normally on the chassis so wiring would have been tough.

 Has anyone tried the Bijou with dt880s? I had a pair previously that I lost and am considering getting another pair. Would 701s pair better with the tube sound?


----------



## holland

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_with, or without the top-plate of the NABU? it could just be RFI. all of my projects are noisy on my workbench until i case them completely up._

 

Just FYI, though I'm sure nobody cares, the buzz was due to a light dimmer in another room. Dimmer has been removed, all quiet.


----------



## holland

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_Has anyone tried the Bijou with dt880s? I had a pair previously that I lost and am considering getting another pair. Would 701s pair better with the tube sound?_

 

Not DT880, but I use a DT990 with it. I think it sounds nice. I'm using the 6N1P input instead of 6DJ8. I will try 6DJ8 again when I get new tubes.


----------



## holland

sextett mp really loving the bijou.


----------



## adamus

can i recommend obbligato caps for the output bypass, really turned my bijou into something. 

 Can i also recommend that people should save there pennies and buy some amperex bugle boy 6dj8's......best valves for the fron end!


----------



## balderon

My Bijou has finally come to life after some tube rolling. I saw the greatest improvement by changing out V1. For now I am using a pair of Philips 6DJ8’s paired with JJ ECC99’s. I took adamus’s suggestion and I am waiting on a pair of Amperex Bugle Boys which test near new. Any recommendations for V2? 

 Some of the other updates are amphead & regal mods, Obbligato Premium @ C1, Auricaps @ C3 & C4, Rubycon @ C5 (thanks pabbi), and Audio Note (UK) Copper Foil @ C6.

 I am noticing a couple of issues with the power supply. First, the B+ voltage will not adjust above ~245 with EZ81 and 270-DAX. I have read many others have this same issue. I have not heard of any adverse effects with the sound/bias so I’ll I am not too concerned. 

 Secondly I find the 270-DAX is running hot. I would guess it’s at least 125F or hotter. The transfo is open air cooled and mounted to 1/8” aluminum. Has anyone else experienced high temperatures? Is this abnormal?


----------



## funch

My 270DAX also gets hot enough that I can only leave my hand on it
 for a couple of seconds. It's also mounted on top of the case. I've
 done the Regal and Amphead mods, and use a separate heater tranny
 for the EZ81. I'm running 6H30's on the input, and ECC99's on the output.

 The other day, I fired it up with no signal and let it run for a few minutes.
 Then I checked the voltages on the amp boards. All were very close except at the junction of C2, R2, and V1 which should read 3V. Mine was at 6.4V.

 Then I connected my source and listened at a moderate volume level for most of a CD. The tranny was still barely warm. Then I turned up the volume one step. By the end of the CD, the tranny was hot again.


----------



## holland

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Can i also recommend that people should save there pennies and buy some amperex bugle boy 6dj8's......best valves for the fron end!_

 

I have amperex orange globe 6dj8's. Do you think bugle boy is better?


----------



## adamus

havent compared them, but the bugleboys are ahead of anything i have tried, which includes Jans, 8416, 6n1p.


----------



## amphead

Well first off thats good news that you get to hear this beauty. I think the 270DAX is known to run quite hot, and depending on how it's loaded it may run hotter. You probably are not going to keep your hand on it too long, even when its working normally. Do an attended burn-in to get a feel for how warm its going to get.

  Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_My Bijou has finally come to life after some tube rolling. I saw the greatest improvement by changing out V1. For now I am using a pair of Philips 6DJ8’s paired with JJ ECC99’s. I took adamus’s suggestion and I am waiting on a pair of Amperex Bugle Boys which test near new. Any recommendations for V2? 

 Some of the other updates are amphead & regal mods, Obbligato Premium @ C1, Auricaps @ C3 & C4, Rubycon @ C5 (thanks pabbi), and Audio Note (UK) Copper Foil @ C6.

 I am noticing a couple of issues with the power supply. First, the B+ voltage will not adjust above ~245 with EZ81 and 270-DAX. I have read many others have this same issue. I have not heard of any adverse effects with the sound/bias so I’ll I am not too concerned. 

 Secondly I find the 270-DAX is running hot. I would guess it’s at least 125F or hotter. The transfo is open air cooled and mounted to 1/8” aluminum. Has anyone else experienced high temperatures? Is this abnormal?_


----------



## rolotube

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_My 270DAX also gets hot enough that I can only leave my hand on it
 for a couple of seconds. It's also mounted on top of the case. I've
 done the Regal and Amphead mods, and use a separate heater tranny
 for the EZ81. I'm running 6H30's on the input, and ECC99's on the output.

 The other day, I fired it up with no signal and let it run for a few minutes.
 Then I checked the voltages on the amp boards. All were very close except at the junction of C2, R2, and V1 which should read 3V. Mine was at 6.4V.

 Then I connected my source and listened at a moderate volume level for most of a CD. The tranny was still barely warm. Then I turned up the volume one step. By the end of the CD, the tranny was hot again._

 

The transformers may be designed to run fairly warm, but I question how long they will last at the highish temp you describe. Here in Oz we have no choice, it has to be the 370 DAX (240V mains) & this seems to be a different beast altogether. I'm running an EZ81, choke PS, 6H30 & ECC99's with regal's & amphead's mods & it never gets much above lukewarm. You can certainly leave your hand on it, even after several hours. I tend to listen at a more or less constant volume (fairly low) & haven't noticed any variation in transformer temp. All voltages are within 10% of "book" values.

 Shinkoh tantalums & Blackgates arrive tomorrow from PcX. Plan is to replace all amp resistors & use Blackgates at C2 (amp) & C3 (PS). I know this is probably overkill but tinkering is fun & may even yield some subtle changes or improvements.


----------



## rolotube

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_havent compared them, but the bugleboys are ahead of anything i have tried, which includes Jans, 8416, 6n1p._

 

The bugleboys get great reports. I've been considering lashing out on some, but they aren't exactly inexpensive. I'd be interested in your comments describing the sound, particularly in comparison with other types. Have you tried any of the 6H30 variants? The DP's in particular are highly regarded by some but are also very expensive. I'm running EH 6H30EB's (gold pins) which are re-badged Sovteks. Very nice, but I now think they produce a sound that is too laid back for my taste. IMO, the Bijou/HD650 combo needs a front end tube with more "punch".


----------



## jkroon

I'm going to build the Bijou as my first DIY amp. I'm waiting for a kit I ordered from GlassJarAudio.com. I was thinking about adding a DIY DAC and DIY phono preamp in the same chassis. I would be concerned with noise, and also the power supply. I have to figure out a good way of doing the power supply layouts. Just thinking about it. I only ordered parts for the Bijou so far. Any thoughts?


----------



## pabbi1

Quote:


  Originally Posted by *jkroon* /img/forum/go_quote.gif 
_I'm going to build the Bijou as my first DIY amp. I'm waiting for a kit I ordered from GlassJarAudio.com. I was thinking about adding a DIY DAC and DIY phono preamp in the same chassis. I would be concerned with noise, and also the power supply. I have to figure out a good way of doing the power supply layouts. Just thinking about it. I only ordered parts for the Bijou so far. Any thoughts?_

 


 Look at the Millett Max in my signature - the OPUS DAC resided in the same case, with no noise whatsoever. The NABU case has a shielded compartment for the psu, except the DAC psu was in the case as well. No problems at all with any noise.

 Now, the Bijou is picky with it's wiring, so you might also look at the various wirings in this thread, including mine in my sig - dead quiet, no noise at all.


----------



## jkroon

I read this entire thread before purchasing the Bijou kit. That's what got me thinking about possible noise problems if I were to add other components. After reading about the ordeal you and Amphead went through, it seems to me that the main things to watch out for are shielding and ground loops, right? Well, I also want to add a source selector, maybe a 3 wire 4 position? I'm not sure. I was going to run shielded twisted pair cables from each input to the selector. Then I would have the left, right, AND shield switched from 4 different inputs. I wanted to wire a DAC to one of those, and have a usb input mounted to the chassis. Then wire a phono preamp to another, and have two more inputs for a CD player and one spare. Another shielded twisted pair would go from the selector to the volume pot, and that's where I start getting confused with the shields and grounding. Maybe I'm overthinking. Would I take the shield to the ground on the volume pot, to the amplifier boards, or to the star ground? I saw your Bijou in previous posts and its insane. I like it.


----------



## jkroon

I haven't even SEEN a tube since about 1985. I can't wait to hear this amp.


----------



## runeight

jkroon could you possible draw a wiring diagram for what you're trying to do?

 The best way to proceed would be to build just the basic Bijou without the selector or other electronics and make it quiet. You're correct that noise is usually ground problems or shielding problems.

 Once you get a quiet amp you can add the other pieces one at a time. Then you'll know, if noise appears, what the cause is. I think this will be a more pleasant experience than ripping things apart to find a problem.

 You've probably already thought of this . . .


----------



## adamus

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_The bugleboys get great reports. I've been considering lashing out on some, but they aren't exactly inexpensive. I'd be interested in your comments describing the sound, particularly in comparison with other types. Have you tried any of the 6H30 variants? The DP's in particular are highly regarded by some but are also very expensive. I'm running EH 6H30EB's (gold pins) which are re-badged Sovteks. Very nice, but I now think they produce a sound that is too laid back for my taste. IMO, the Bijou/HD650 combo needs a front end tube with more "punch"._

 

a very 3d presentatain, punchy bass that also drops deep. big mids, and extended highs. 

 They are the most '3d' sounding tube i have tried. 

 Again, looking at the operating point of the amp, even with regals mod, you would expect the 6dj8 to sound better than the russians mentions, we are in a more linear region.


----------



## balderon

Hi Alex. I am enjoying the Bijou however I wanted to get your opinion on enhancement I am considering. I am siphoning about 20ma from the B+ and each channel is drawing ~38ma each for a total of ~96ma. I am finding the supply cannot deliver sufficient power for this load. With a 90ma 270DAX transfo (w/EZ81/Regal mod) my B+ is dropping to < 238v@96ma. P1 had little effect past midpoint. Once I reduce the current load, P1 once again adjusts the output voltage. Also the transfo is running very hot. I wanted to upgrade to a 270FX (275-0-275@150ma) to provide additional current and to reduce the heat (I hope).

 It looks like the MOSFET/EZ81 can accommodate the additional power but would you recommend changing Q1/Q2 bias points? Any suggestions you have will be greatly appreciated.

 TIA


----------



## balderon

I googled this problem and it seems to be very common with the hammond transfo. One of the posts I read on one of the other sites indicated using several Hammond transfo for the last 10 years. They run very hot and was used in different amps without problems.

  Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_My 270DAX also gets hot enough that I can only leave my hand on it
 for a couple of seconds. It's also mounted on top of the case. I've
 done the Regal and Amphead mods, and use a separate heater tranny
 for the EZ81. I'm running 6H30's on the input, and ECC99's on the output.

 The other day, I fired it up with no signal and let it run for a few minutes.
 Then I checked the voltages on the amp boards. All were very close except at the junction of C2, R2, and V1 which should read 3V. Mine was at 6.4V.

 Then I connected my source and listened at a moderate volume level for most of a CD. The tranny was still barely warm. Then I turned up the volume one step. By the end of the CD, the tranny was hot again._


----------



## pabbi1

On reflection, most of my noise problem was the TUBES, the 6n1p and 6n6p - after burning for about 150-200 hours, they settled down, and are dead quiet. The attenuators were a different problem (very small lead pads), and switching to the TKD helped there as well.

 Oh, and new builders (or anyone, for that matter): Shoot me a PM if you want Rubycon photoflash caps - I still have plenty - and, grattis.


----------



## pabbi1

just a heads up...

 There are some smoking deals on ez81 on eBay at the moment. 

 I have no knowledge nor affiliation with this seller - and have plenty of EZ81 put back - for at least 4x what these auctions might go for.


----------



## MoodySteve

Thanks for the heads up pabbi1, been looking for a good price EZ81


----------



## jkroon

Runeight, you're absolutely right of course. I'm getting impatient and jumping the gun. I would draw a picture of what I'm talking about but I have no idea how to draw a 3 pole 4 position switch. I'll do like you say and start with the original design. Once I have a working Bijou, I'll bring it up again. For now, since I'm still waiting for my parts to get here, I'll start on a chassis. I bought some maple wood and 1/4" aluminum plate today. And I have a steel drawer from an old desk I think I could use.... What a fun hobby this is! I can see this easily getting out of hand.


----------



## runeight

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_Hi Alex. I am enjoying the Bijou however I wanted to get your opinion on enhancement I am considering. I am siphoning about 20ma from the B+ and each channel is drawing ~38ma each for a total of ~96ma. I am finding the supply cannot deliver sufficient power for this load. With a 90ma 270DAX transfo (w/EZ81/Regal mod) my B+ is dropping to < 238v@96ma. P1 had little effect past midpoint. Once I reduce the current load, P1 once again adjusts the output voltage. Also the transfo is running very hot. I wanted to upgrade to a 270FX (275-0-275@150ma) to provide additional current and to reduce the heat (I hope).

 It looks like the MOSFET/EZ81 can accommodate the additional power but would you recommend changing Q1/Q2 bias points? Any suggestions you have will be greatly appreciated.

 TIA_

 


 Yes, you can use the bigger transformer without changing the op points for the mosfets.

 However, watch out for the heater voltage. The bigger transformer probably has a large current heater winding. Since it will be more lightly loaded it will have a higher voltage.


----------



## luvdunhill

someone needs to put a bug in pabbi1's ear about those Amperex "upgrade" tubes


----------



## pabbi1

Noooooooooo - my Bijou needs Regal mods first, and the cathode resistor is NOT socketed, so that is the last thing I need to do - modding a working amp.

 Besides, Raven is being biased as we speak, and I have been buying 307a, 7w7, and 5v4 (along with a couple of pairs ov 83 and 866a), so the Bijou is staying exactly as it is - unless someone else wants to mod it, or, it gets a new home.


----------



## balderon

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yes, you can use the bigger transformer without changing the op points for the mosfets.

 However, watch out for the heater voltage. The bigger transformer probably has a large current heater winding. Since it will be more lightly loaded it will have a higher voltage._

 

The parts should be delivered Tuesday. I hope it will solve my thermal problem. Thank you for the help.


----------



## jkroon

Attachment 17356
 Here's what I have done so far. Still waiting on the bijou kit. The sides are soft maple, the top and bottom are 1/4" aluminum plate. I brushed the aluminum with a wire wheel, hard to see in the picture. Inspired by Amphead's oak and cocobolo chassis on post #136 of this thread. I know, no points for originality here. But this is the first time I've ever even cut a piece of wood.


----------



## jkroon

Attachment 17358
 And here's the inside.


----------



## TimJo

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_just a heads up...

 There are some smoking deals on ebay at the moment. 

 I have no knowledge nor affiliation with this seller - and have plenty of EZ81 put back - for at least 4x what these auctions might go for._

 

Thanks for the tip pabbi!!! I was able to pick up a pair RCA's for $11.50 
	

	
	
		
		

		
		
	


	




 I also got a pair of Amprex 6dj8's from the same guy for really cheap. 

 I hope some others were able to score some as well...


----------



## emelius

no balanced super bijou plans yet?...


----------



## jkroon

OK, I got most of my stuff from glassjaraudio.com. I'm still missing the tube sockets and the two pin phoenix connectors. Everything is soldered on the boards except for those two items. While I'm waiting for my parts to arrive I have a question about the voltages. On my transformer I'm getting 300V instead of 260v, and 7.5V instead of 6.3V. The power at the outlet is 120V. The primary of the transformer is 115V. I guess the slightly higher primary voltage (+5V) is the reason for the higher secondary voltages, but will this be OK?


----------



## Clutz

You're probably getting 300V instead of 260 and 7.5V instead of 6.3 because the transformer is unloaded. 

 120 / 115 = 1.043. 300 / 260 = 1.15, 7.5 / 6.3 = 1.19.

 So, the extra five volts of input is about 4.3% higher than expected, but the output voltages are 15 and 19% higher. 

 It's because the transformers are unloaded.


----------



## balderon

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yes, you can use the bigger transformer without changing the op points for the mosfets.

 However, watch out for the heater voltage. The bigger transformer probably has a large current heater winding. Since it will be more lightly loaded it will have a higher voltage._

 

As expected changing to the 270FX worked out very well. The tranfo barely warm and the B+ is at spec with plenty of power to spare (even after drawing the additional 20ma). The heater voltage increased to only 6.5v.


----------



## pabbi1

Quote:


  Originally Posted by *emelius* /img/forum/go_quote.gif 
_no balanced super bijou plans yet?..._

 

My balanced Bijou sounds pretty super with the hd800...


----------



## bhjazz

Quote:


  Originally Posted by *emelius* /img/forum/go_quote.gif 
_no balanced super bijou plans yet?..._

 

The Super Bijou is listed at Cavalliaudio as "in the works." We'll see what lies ahead, but I'll bet Alex has something cool up his sleeve.







 1300


----------



## TimJo

He gave us a preview a few months back.... 
	

	
	
		
		

		
		
	


	




Bijou II


----------



## bhjazz

Quote:


  Originally Posted by *TimJo* /img/forum/go_quote.gif 
_He gave us a preview a few months back.... 
	

	
	
		
		

		
		
	


	




Bijou II_

 

Nice catch! I completely forgot about that little post. Thank you TJ!


----------



## mugdecoffee

I just made a szekeres amp/buffer and was thinking about adding it as an active ground channel to my bijou amp. Is there anything wrong with this? For wiring I'm thinking input ground->buffer input and power from a regulated 12v grounded to start ground. Does that make sense?

 Should the active ground improve the sound somewhat? Is there any disadvantage to using a solid state ground buffer or one of a different design than the rest of the amp? Am I missing something?

 Also, it be too much to ask of the 270dax to get the 12v supply from the two heater windings in parrallel, no?


----------



## zkool448

Well, after completing a couple of projects I now plan to invest the little free time I have on the next amp on my wishlist - The "Gem" (I think it's what this group calls it, but in french 
	

	
	
		
		

		
			





)

 I've have the approval from the management, er.. I meant the wife that I can now finally confirm a kit order to Jeff. I recall someone mentioned _he was hunting for wolverines in Alaska_ last time I checked. 
	

	
	
		
		

		
		
	


	




 Really excited to get building on this based on sooo many good reviews I've read. For the case I think I'll go naamanf-style.


----------



## adamus

zkool448, superb choice my friend!

 Obbligatos for the bypass caps and amperex bugle boys for the input valves and you will have a superb amp. 

 I now have the biju and a CTH. massively different sound signature. The combo of senn 650's with the bijou is heavenly, massive soundstage, detail and a lush mid range. it is my benchmark combo. The bijou does not work as well in my humble opinion with grados, infact i prefer the CTH with grados.


----------



## fishski13

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_Well, after completing a couple of projects I now plan to invest the little free time I have on the next amp on my wishlist - The "Gem" (I think it's what this group calls it, but in french 
	

	
	
		
		

		
		
	


	




)

 I've have the approval from the management, er.. I meant the wife that I can now finally confirm a kit order to Jeff. I recall someone mentioned he was hunting for wolverines in Alaska last time I checked. 
	

	
	
		
		

		
		
	


	




 Really excited to get building on this based on sooo many good reviews I've read. For the case I think I'll go naamanf-style.
_

 

excellent decision. the Bijou's greatest strength is the felling that you're there, front row, and everything is "alive". its soundstaging abilities and wonderful mid-range turns the HD650 into an K701, but with a bit more dense tones and excellent bass response. the K701 still wins out for transients.

 i'm on the home stretch, the CK2III/pre-amp/y-1 DAC i'm building for a friend is nearly complete. then i get to re-vamp by Bijou!!! can't wait to hear the Mundorf output caps and Regal's Mod.


----------



## zkool448

adamus, obbligatos and amperex bugle boys -- checked!

 Since I have to source my own transformer, pre-reading the thread I see a few options mentioned already such as the 370/270 DAX, and 270FX... recommendations? I'd have to source it early so it arrives roughly about the same time with Jeff's kit. cheers.

_edit: fishski13: can't wait to hear the Mundorf output caps and Regal's Mod._ It sounds like I have a lot of reading ahead


----------



## adamus

I used Rcore tranformer from vt4c


----------



## TimJo

I'm still putting together parts for mine, but I have decided on using the 370 DAX on my build, partly based on n_maher's comment back in '07, when I was just lurking in the corners, thinking about getting into DIY...

  Quote:


  Originally Posted by *n_maher* /img/forum/go_quote.gif 
_Someone should have a go at building the amp with the 370DAX. The voltage specs are exactly the same but the 370 is a lot more robustly designed. I've heard from multiple sources, and heard it myself, that over time the 200 series trafos have a habit of getting noisy, running hot, etc. I know that when I replaced the 200 series trafo in my Wheatfield with the equivalent 300 series the operating temp went down a good 20 degrees and the 300 was silent compared the rather buzzy 200.

 Just my 2c, and yeah, I'm in for a pair of boards or maybe more...

 Nate_


----------



## fishski13

Quote:


  Originally Posted by *TimJo* /img/forum/go_quote.gif 
_I'm still putting together parts for mine, but I have decided on using the 370 DAX on my build, partly based on n_maher's comment back in '07, when I was just lurking in the corners, thinking about getting into DIY..._

 

that's why i went with the 370 as well. it barely gets warm and is dead silent. 

 i used a 269EX in a guitar amp i recently built, and yes, it does have a faint buzz at the TX itself, but no noise through the speaker.

 TimJo,
 i used to own the DT880 - i think it would be perfect with the Bijou. i've been toying with the idea of getting another pair.


----------



## zkool448

adamus, happy with vt4c's rcore? their prices also look very reasonable.

 Angela’s seem to be the cheapest 370 unless someone knows of other online shops that ship to canada. (*balderon, I see you're looking to unload one, will take them of your hands if willing to ship outside conus).

 fishski13, worthy choice could be the custom manufaktur dt880/600 ohms


----------



## balderon

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_adamus, obbligatos and amperex bugle boys -- checked!

 Since I have to source my own transformer, pre-reading the thread I see a few options mentioned already such as the 370/270 DAX, and 270FX... recommendations? I'd have to source it early so it arrives roughly about the same time with Jeff's kit. cheers._

 

I had significant heat problems with both the 270DAX and 370DAX. I am using the EZ81 with Regal mod, 6DJ8's/ECC99's and with the inputs grounded my B+ was only 235V and the current was near the 90ma - which is the maximum rated current for the transfo. I would recommend upgrading to something larger. I installed a 270FX (275-0-275@150ma) and all my problems are gone (see previous post) and the background is dead silent.


----------



## zkool448

I've not perused the entire thread thoroughly but aware of the ez81/regal mod. I do regret not opting for a higher current trafo with the SOHA II build (currently only tubes @ 300mA max draw). I now ponder if I face a similar scenario by settling with the 370dax


----------



## MoodySteve

Hi all,

 Since headwize is still down I suppose I have to post my question here. I think I know the answer but better safe than sorry!

 Anyhow, due to my casing design choices (viz. using 1" thick wood as the material of choice) I will not be able to use the 250kΩ feedback pot because the shaft is too short to secure a knob onto. I know, great priorities.

 I know that I could re-do the front panel such that I could get it to fit, but I'd rather not travel down that road if I don't need to. At Mouser I managed to find a dual-gang linear taper series of pots with an acceptably long shaft, but it's not available in 250kΩ - only 100kΩ and 500kΩ.

 So, is there any problem subbing either of those two pots for the 250k, and would I be better off getting the 100k or the 500k? I will be using the amp with 30Ω headphones so I will be using NFB.


----------



## wiatrob

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_adamus, obbligatos and amperex bugle boys -- checked!_

 

My Bijou looks to be "on hold" so I may have some Obligatos for you (in fact I tried a pair in a CTH... 
	

	
	
		
		

		
		
	


	




) PM me...


----------



## adamus

big fan of the obbligatos, significant improvement to my ears. 

 Zkool, yes, the vt4c tranformer. IT is cheap, but the shipping is expensive.


----------



## luvdunhill

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_So, is there any problem subbing either of those two pots for the 250k, and would I be better off getting the 100k or the 500k? I will be using the amp with 30Ω headphones so I will be using NFB._

 

why not use the 500K pot with a parallel resistor to emulate a 250K pot? I'm assuming these are linear pots?


----------



## balderon

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_I know that I could re-do the front panel such that I could get it to fit, but I'd rather not travel down that road if I don't need to. At Mouser I managed to find a dual-gang linear taper series of pots with an acceptably long shaft, but it's not available in 250kΩ - only 100kΩ and 500kΩ._

 

I had a similar problem with the short shaft on the NFB pot. My solution was to purchase a shaft extension kit and mount the pot further inside the case.


----------



## zkool448

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_big fan of the obbligatos, significant improvement to my ears._

 

_Bill, ygpm 
	

	
	
		
		

		
			



_ 

  Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Zkool, yes, the vt4c tranformer. IT is cheap, but the shipping is expensive._

 

Thanks adamus. I checked some prices again and seems like the hammonds could end up costing more after shipping to Toronto.

 Angela:
 370DAX $68 + $30 s/h
 270DAX $47 + $30 s/h
 270FX $57 + $30 s/h

 vt4c: 
 R0080-036 $34 + s/h? 

 While wiring the hammond looks well documented over at runeight's website, I'd really like to go with the low-profile Rcore. My concern is it could be more complicated -- is there an Rcore diagram floating around somewhere? (sorry but I'm only on page 49 of the thread, I'm a slow reader 
	

	
	
		
		

		
		
	


	




).


----------



## fishski13

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_Bill, ygpm 
	

	
	
		
		

		
		
	


	


 



 Thanks adamus. I checked some prices again and seems like the hammonds could end up costing more after shipping to Toronto.

 Angela:
 370DAX $68 + $30 s/h
 270DAX $47 + $30 s/h
 270FX $57 + $30 s/h

 vt4c: 
 R0080-036 $34 + s/h? 

 While wiring the hammond looks well documented over at runeight's website, I'd really like to go with the low-profile Rcore. My concern is it could be more complicated -- is there an Rcore diagram floating around somewhere? (sorry but I'm only on page 49 of the thread, I'm a slow reader 
	

	
	
		
		

		
		
	


	




).
_

 

$30 shipping???
	

	
	
		
		

		
		
	


	




 can't you find a Canadian vendor? 

 Radio Daze is A+++: Radio Daze. i would see what they can do for you.


----------



## amphead

Nice to see so many successful builders keeping up the good fight. I wasn't able to finish my volume assemblies in time for CanJam, but I picked up Amb and all that beautiful equipment in Sunnyvale, then we all went down in my rental car to LA. The show was a lot of fun and I provided a laser light show for some members after hours. The ability to produce these lasers from scratch turned into an obsession.  I will be getting back to my build soon.





 -> ME


----------



## MoodySteve

Thanks for the suggestions guys.

 I have a few shaft extension kits but this particular build isn't too friendly towards using one (nearly everything is being mounted on the bottom of the top plate via blind tapped holes). I will bear it in mind, though. I'll probably try luvdunhill's idea and parallel the 500k pot with a 500k resistor on each wiper.


----------



## zkool448

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_$30 shipping???
	

	
	
		
		

		
		
	


	




 can't you find a Canadian vendor? 

 Radio Daze is A+++: Radio Daze. i would see what they can do for you._

 

fishski13, tried to source one locally and they're right about in the same ballpark, as well as radio daze's price as it appears.
 Radio daze
 HX-370DAX $68.60 + s/h

 Parts Connexion
 270DAX $60.34 + shipping
 270FX $75.00 + shipping

 I'll give R-core R0080-060 a try and hopefully the wiring isn't excessively convoluted to figure out -- I'll post up a wiring diagram once I get it going. cheers.


----------



## adamus

with the Rcore you can also use 12v tubes like the 8416 for the input tubes with a bit of creative wiring


----------



## SBoy

Hi guys. I've finally finish the Bijou; cased up and sounds really good. I love the fact that the music is presented along my eye level instead of above my forehead. I've some problem though, buzzing noise are audible at times else it is completely silence. The buzzing sound comes and goes as it likes. Any suggestions?


----------



## adamus

tubes, are the new? or it could be interference, valves amps tend to be more sensitive.


----------



## naamanf

Quote:


  Originally Posted by *SBoy* /img/forum/go_quote.gif 
_Hi guys. I've finally finish the Bijou; cased up and sounds really good. I love the fact that the music is presented along my eye level instead of above my forehead. I've some problem though, buzzing noise are audible at times else it is completely silence. The buzzing sound comes and goes as it likes. Any suggestions?_

 

Could be interference. Is it a continuous buzz or does it sound a bit more like Morse code?


----------



## SBoy

They are NOS tube. Continuous buzz, I've isolated heaters cable from the signal cables so i guess other things are causing this. I forgot to mention that the buzz become louder when I tuned my NFB port to max Z.


----------



## balderon

Quote:


  Originally Posted by *SBoy* /img/forum/go_quote.gif 
_They are NOS tube. Continuous buzz, I've isolated heaters cable from the signal cables so i guess other things are causing this. I forgot to mention that the buzz become louder when I tuned my NFB port to max Z._

 

I had a similar problem when my metal chassis was connected to earth ground but the chassis was isolated from signal ground (star ground). I eliminated the buzzing once I connected earth ground to the star ground. Another source of noise I experienced was the outer shield of the NFB pot was not connected to the chassis. The shield of the NFB pot was acting like a big antenna!


----------



## SBoy

I grounded the casing of NFB and the buzzing is so much less audible now. It still come and goes as it likes. Another problem is when i turn down my volume all the way down and my NFB all the way up; I could still hear music being played. Am I looking at a faulty NFB pot?


----------



## rolotube

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_excellent decision. the Bijou's greatest strength is the felling that you're there, front row, and everything is "alive". its soundstaging abilities and wonderful mid-range turns the HD650 into an K701, but with a bit more dense tones and excellent bass response. the K701 still wins out for transients.

 i'm on the home stretch, the CK2III/pre-amp/y-1 DAC i'm building for a friend is nearly complete. then i get to re-vamp by Bijou!!! can't wait to hear the Mundorf output caps and Regal's Mod._

 

Well said. fishki. The Bijou & HD650 combo puts you IN the music. My 701's just don't work. Admittedly I've dispensed with NFB so they probably aren't being driven as optimally as the 650's, at least as far as impedance is concerned.

 Just finished replacing all resistors in the amps with Shinkoh tantalums & C2 with Blackgate NX (non-polarised, 1500uF 10V) . Early days yet but a tangible improvement in detail, resolution & presence is evident. Like another thin veil has been lifted from the fabric of the music. I expect this will change (improve?) as they burn in. Not sure how much is attributable to the Shinkoh's or Blackgate's, but at least its forward progress.

 IMO, this is one of the great attributes of the Bijou. Tweaks & changes are relatively easy & often produce unexpectedly significant improvements. I'm running regal's mods & have just gone back to the NOS Philips 6922's supplied with the kit. Sound is much more forward, "in your face" & punchy than the 6H30's, but still beautifully lush & full, particularly the mids & tops. I think these tubes have been unfairly maligned by some; in my build at least, the result is extremely pleasing. Not better or worse than the 6H30 or 6n1P, just different. Recent posts sing the praises of Amperex Bugle Boys. They should go well with regal's mods which run them at an improved operating point. It seems there are many variants of this tube, including Chinese copies, & prices range, not surprisingly, from the sublime to the ridiculous. I'll take my time & choose carefully before launching into these.

 What Mundorf's are you planning on using on the outputs? 200uF 550V Tubecaps (not bypassed) are working very well for me, but are expensive & require significant off-PC board space to mount.


----------



## fishski13

my yet-to-be soldered Mundorf caps are only 150uF/250V - one for each channel. if i feel i need more damping power, i'll buy another pair for each channel for 300uF.

 i think it will end up being an HD650 amp. i have no NFB as well.


----------



## zkool448

All the impressions here are getting me all wound up - anyone listening to the Bijou and DT880/250 combo? 

 Really appreciate the obbligatos wiatrob, and balderon & zare for offering up a spare trafo 
	

	
	
		
		

		
		
	


	




 Sure made obtaining parts _less_ trickier. All that's left is for the kit/boards/parts to arrive that Jeff sent out, then should be all set to join in the fun! ...(albeit with problems haha)

  Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_with the Rcore you can also use 12v tubes like the 8416 for the input tubes with a bit of creative wiring_

 

I'd awkwardly beg you for a diagram if/when time comes since I'd never be able to figure that one out


----------



## holland

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_I'll give R-core R0080-060 a try and hopefully the wiring isn't excessively convoluted to figure out -- I'll post up a wiring diagram once I get it going. cheers._

 

The wiring is easy peasy, just many wires. Nothing different than others if you mind the colors.

 For the 6.3V wires, the easiest thing to do is connect the CT. The black wires for the 2 6.3V windings. This way you can determine phase very easily with a DMM set to measure AC voltage.

 Edit: disconnect the black wires after you determine phase especially if you're going for 12.6V. To wire for 12.6V and 6.3V I would use a junction block and you can wire one tube with a series connection and others in a parallel connection.

 I used a resistor on the windings to drop some voltage, FWIW, as you're running a 6A xformer and the heater will be a tad high.


----------



## zkool448

Thanks Holland. _(..copy and pasting all good info into one 'Bijou' notepad as I peruse the entire thread)._

 I always find things makes much more sense if I have parts in front of me ...biggest problem I have is over-analyzing things too much 
	

	
	
		
		

		
			





. cheers.


----------



## dBel84

I knew I had a copy of PRR's image from the HW thread 
	

	
	
		
		

		
		
	


	









 ..dB


----------



## zkool448

OMG. You guys never cease to amaze me... much appreciated.

 i love this place.


----------



## adamus

I had to use a 0.22 ohms power resistor to drop the voltage on mine, it was high at around 7.3 if i remeber correctly


----------



## jkroon

Finished building amp. Sounds good, but both channels are buzzing with or without input connected, regardless of volume control setting. Buzzing is louder if I take the cover off.

 I was closing the cover and it slipped and banged shut. The noise went away immediately. Now I only hear buzzing when I turn my head to the right. I think my amp is playing mind games with me.


----------



## runeight

jkroon, does this mean it's quiet now? If not, the symptons might indicated a loose wire or a bad solder joint on one of the PCBs or a bad ground condition somewhere.


----------



## jkroon

I figured it out. It had to do with the routing of the wiring from the RCA jacks to the volume pot. They were laying on the amp boards. I fastened them to the side of the chassis with a sticky block and a zip tie. Now it's dead silent. I left the amp on overnight with some pink noise playing. It sounds much better now than it did last night.


----------



## zkool448

Congrats jkroon, sounds like you barely broke a sweat as I recall you were waiting on a kit just two weeks ago 
	

	
	
		
		

		
		
	


	




 I just got through the entire thread and hope to join you soon. 

 My brother-in-law installs home security systems and gave me 50ft of stranded 18AWG wire (black/white twisted, insulated) unsure know what it's max voltage rating is. Is the wire overkill for the supply voltages and for hookups instead of the recommended 20-22 awg?


----------



## DoYouRight

Seemingly this might be the best option for an alternate to my B22 build but it's very hard to choose just one Cavalli Tuber!


----------



## fishski13

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_My brother-in-law installs home security systems and gave me 50ft of stranded 18AWG wire (black/white twisted, insulated) unsure know what it's max voltage rating is. Is the wire overkill for the supply voltages and for hookups instead of the recommended 20-22 awg?_

 

it depends on the material of the dielectric. if you can't find out the rated specs, i wouldn't use it for the B+ wire, or for the HT wires off the TX. you can use it for signal wiring though. filament wiring also carries some current - i'm not sure i would use it here either. 

 you build beautiful but flammable wood enclosures. 

 ebay seller Navships has teflon SPC for dirt cheap.


----------



## fishski13

Quote:


  Originally Posted by *DoYouRight* /img/forum/go_quote.gif 
_Seemingly this might be the best option for an alternate to my B22 build but it's very hard to choose just one Cavalli Tuber!_

 

yes, i want to build another 
	

	
	
		
		

		
		
	


	




.


----------



## zkool448

Thanks fishski13.

  Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_it depends on the material of the dielectric. if you can't find out the rated specs, i wouldn't use it for the B+ wire, or for the HT wires off the TX. you can use it for signal wiring though. filament wiring also carries some current - i'm not sure i would use it here either._

 

Cool. I won't be using them. Thought I could save a few bucks since it's free (btw learned later its rated at 600V). Another thing is after examining the wires, I recall Alex mentioned about the possibility of having troubles while trying to get multiple wire ends into the terminal blocks.

  Quote:


 you build beautiful but flammable wood enclosures. 
 

compliment or did I just get spanked? 
	

	
	
		
		

		
		
	


	




 seriously now you've got me concerned. Sometimes folks here overlook that I'm still a complete novice (totally different field of work) and I don't pretend I know what I'm doing, hence the dumb questions. But I'm sticking around and doing my best to learn what I can, so I'd appreciate to know what to do/avoid since I fail to see the hazard or how my enclosures are different from others' wood Bijou cases.

  Quote:


 ebay seller Navships has teflon SPC for dirt cheap. 
 

Did received a couple of links from balderon pointing to navships listings (20 and 22 AWG) which I had just purchased -- John's stuff are definitely a bargain.


----------



## fishski13

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_Thanks fishski13.


 Cool. I won't be using them. Thought I could save a few bucks since it's free (btw learned later its rated at 600V). Another thing is after examining the wires, I recall Alex mentioned about the possibility of having troubles while trying to get multiple wire ends into the terminal blocks.


 compliment or did I just get spanked? 
	

	
	
		
		

		
		
	


	




 seriously now you've got me concerned. Sometimes folks here overlook that I'm still a complete novice (totally different field of work) and I don't pretend I know what I'm doing, hence the dumb questions. But I'm sticking around and doing my best to learn what I can, so I'd appreciate to know what to do/avoid since I fail to see the hazard or how my enclosures are different from others' wood Bijou cases.


 Did received a couple of links from balderon pointing to navships listings (20 and 22 AWG) which I had just purchased -- John's stuff are definitely a bargain._

 

no dumb questions, especially with high voltages. the Bijou is an easy build, but you must be mindful of the dangers of working with these high voltages. 

 i wouldn't worry about using a wood chassis. 

 600V is plenty good. yes, even 20 gauge took a bit of effort to squeeze into the Phoenix terminals. don't tin the stripped ends - just give them a tighter twist. a pair of hemostats are handy for inserting into the terminals.


----------



## zkool448

I think I have mostly everything I need to build …except for the kit 
	

	
	
		
		

		
		
	


	




 I was expecting to see it today but it never arrived. Guess I’ll have to wait a couple more days until post reopens on Monday.


----------



## adamus

dont forget, if you are wiring the heater secondaries in parallel, make sure you get them in phase, or I think (and i may be very wrong!) you can use the Ct's.


----------



## zkool448

Thanks adamus, I'll be careful and triple check my wiring.

 I also picked up a few 2W power resistors in case the need to drop a few voltages. I'll be doing Regal’s mod right away, and use sip sockets for R2, output and bypass caps (obbligatos in transit). cheers.


----------



## jkroon

This amp sounds better and better the more I listen to it! 
 ZKOOL- I used that transformer. I rang all the wires to find each set of windings. Then I connected it to 120V and checked the voltages to be absolutely sure because my wire colors didn't match what was on the label. I wrote down the voltages and wire colors, powered down, then did all my connections to the board.


----------



## zare

Quote:


  Originally Posted by *jkroon* /img/forum/go_quote.gif 
_This amp sounds better and better the more I listen to it! 
 ZKOOL- I used that transformer. I rang all the wires to find each set of windings. Then I connected it to 120V and checked the voltages to be absolutely sure because my wire colors didn't match what was on the label. I wrote down the voltages and wire colors, powered down, then did all my connections to the board._

 

Now that's scary.. I've actually sold the transformer to zkool, but never bother to check it as I have started collecting part for balanced version and this transformer did not have enough power. 
 From the Bijou veterans here .. knowing that torus transformers are no-no for this kind of build ( or maybe I am wrong), what will be the recommended specs for customer EI? Something like this maybe:

 Power transformer 130VA
 Primary: 115/230V, 50-60Hz
 Sec. 1: 260-0-260V @ 200mA
 Sec. 2: 6.3V @ 4A
 Qty: 2


----------



## zkool448

Jkroon thanks for the heads up, and zare no worries - all is good. 

 I’ve plugged the r-core (slo-blow fuse, 1A) but I haven’t tinkered with the tx secondary filaments completely. What i’ve done so far is just measure the windings voltages and other values in reference to the taps (based on the wiring label sticker). All the voltages checks out according to the color/label sticker, though measurements are a bit on the high side (unloaded perhaps).


----------



## fishski13

finally...busting into the Bijou tonight with Regal's Mod and Mundorf output caps. i'm keeping the original chassis and no P2P.


----------



## zkool448

Ok folks, I've tinkered and done a bunch of readings with my r-core transformer and after reviewing what others have posted about wiring it up, below is what I think how it all ties up to the PS board and which windings to draw voltages for the heaters (6.3v/12.6v). 

 Even if you don't own an r-core tx, could you tell from my wiring diagram if this looks right?


----------



## runeight

Correct.


----------



## zkool448

awesome. now I can sleep


----------



## cgrums

Well my bijou is nearly there. It's been a long time coming and there have been more than a few issues along the way. Current issue; my B+ is rock steady at 250 VDC right up to the point when I put the 6H6PI tubes in. After connecting the output tubes B+ drops to ~138 VDC and I'm not able to adjust. Thoughts?


----------



## balderon

.


----------



## runeight

Quote:


  Originally Posted by *cgrums* /img/forum/go_quote.gif 
_Well my bijou is nearly there. It's been a long time coming and there have been more than a few issues along the way. Current issue; my B+ is rock steady at 250 VDC right up to the point when I put the 6H6PI tubes in. After connecting the output tubes B+ drops to ~138 VDC and I'm not able to adjust. Thoughts?_

 

cgrums, I'm sorry to say that this usually means that the mosfets in the PS are blown. This happens if you accidentally short the output of the PS when it's powered up. If you replace them both the PS will probably come back to normal.


----------



## cgrums

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_cgrums, I'm sorry to say that this usually means that the mosfets in the PS are blown. This happens if you accidentally short the output of the PS when it's powered up. If you replace them both the PS will probably come back to normal._

 

Hmm...I was afraid of that. I did for sure fry the mosfets once but replaced both. Might've fried them again. I'll order some more just in case.


----------



## Proutch

A new Bijou came to life last night! 
	

	
	
		
		

		
		
	


	




 He (or she?) was born in Paris, France.
 Along with my K701, they need to be burnt in.
 But to describe the pre burn-in sound I would say: crisp, warm, detailed, harsh, almost saturated sometimes.

 That was fun to build anyway. As you see below, the casing is not particularly fancy. The only specificity might be the quite compact design (it's a 23cmx23cm case)


----------



## fishski13

Proutch,
 EXCELLENT!!!


----------



## Forte

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_A new Bijou came to life last night! _

 

Wow, great job fitting it all into such a small enclosure. Very neat job on the wiring.


----------



## zkool448

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_A new Bijou came to life last night! 
	

	
	
		
		

		
			



_

 

Proutch, nice wiring. When I finish populating my boards, can I send you mine so you can wire it up for me? 
	

	
	
		
		

		
		
	


	




 nice job!


----------



## runeight

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_A new Bijou came to life last night! 
	

	
	
		
		

		
		
	


	




 He (or she?) was born in Paris, France.
 Along with my K701, they need to be burnt in.
 But to describe the pre burn-in sound I would say: crisp, warm, detailed, harsh, almost saturated sometimes.

 That was fun to build anyway. As you see below, the casing is not particularly fancy. The only specificity might be the quite compact design (it's a 23cmx23cm case)
_

 


 Really nice work Proutch. 

 May I ask, did you really mean to say "harsh" for the sound? I'm asking because, the Bijou is rarely ever described as harsh, even by those who don't like it very much. This makes me wonder if there might be something wrong?


----------



## amphead

Nice build Proutch. Yeah, I'm curious about your description of the sound. Almost sounds like your source is interacting negatively with the Bijou. Some have found problems with their source, but rarely anything but beautiful sounds from the Bijou.

 As for me, I'm working on wiring up my balanced Bijou into its new enclosure. It will be single ended for awhile though.

 This was an earlier distraction from the build........


----------



## bhjazz

Proutch - beauty! That's a reference build for sure. The case looks like a Hi Fi 2000. I like using the slots in the side panels for running wires like you did. It helps the clean look. Good work!

 amphead - I'll bet you have been hanging out on the CandlePower forums... A 384mW...must be spendy! Sweet!


----------



## smeggy

Very sweet build. Hope it sounds as good as it looks.


----------



## Proutch

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Really nice work Proutch. 

 May I ask, did you really mean to say "harsh" for the sound? I'm asking because, the Bijou is rarely ever described as harsh, even by those who don't like it very much. This makes me wonder if there might be something wrong?_

 


 Hey guys, thanks a lot for your warm comments!!! 
	

	
	
		
		

		
		
	


	




 The wiring actually took much, much longer than populating the boards...

 I also suspect that there might be a slight issue. But my K701 are brand new and I heard they usually sound a little harsh before they burn in. We'll see after a few hours... The issue is I don't have other highend cans nor amp to compare
 I also noticed that sound is cleaner with maximum negative feedback (ie making volume lower, am I getting this right?). In general, how do you recommend to set NFB for K701?


 Another worry is that the transfo got super hot last night (while it's a 370). I checked B+ and it was 254V, so I tweaked the pot to 250V. Not sure this was related.
 I thought heat could also be a consequence of the compact design. If that proves right, I'll punch additionnal holes in the cover for extra cooling.


 However, the very good surprise is that it is DEAD QUIET.
 Initially, I feared compact build could lead to increased noise/hum. I put some thinking in wiring/board placing to avoid any power wire to cross signal wires. Also, running wires in separate side panel slots might not be that bad an idea


----------



## Dantes

An other bijou is alive, very good news, and in france... very very good news. 
	

	
	
		
		

		
		
	


	




 Proutch, i work in Paris, maybe we could compare our bijou ?
 It could be interesting


----------



## TimJo

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_A new Bijou came to life last night! 
	

	
	
		
		

		
		
	


	


_

 

Looks great Proutch ! 
	

	
	
		
		

		
		
	


	




 I can tell you put a lot of thought into the layout and the separation of the signal and power lines.

 It would be interesting to compare the two Bijou's. If you two get together, let us know what you find...


----------



## amphead

Proutch, it is normal for the Transformer to be quite hot. During burn-in however you don't want to leave the amplifier unattended until you get a feel for how it is behaving. It's ok to carefully put your hand on the iron of the trafo, to see how it's doing. That is part of the characterization process. If it gets hot enough to create smoke, then there is a problem somewhere, otherwise just expect the 370 to run quite warm. The size of the enclosure also determines an amplilfiers ability to handle heat. You have built it into a beautiful, but small enclosure which means heat will take longer to dissipate. After the burn-in, running it for several days on and off, you should see that everything is fine. But don't worry as long as it sounds good and you see no smoke during this burn-in. Again, NICE WORK!


----------



## jamess71

Proutch Great Job. I love the nice and neat wiring.


----------



## balderon

I thought it was time to show some work in-progress pics. The casework is nearly complete and only a few more things left to do. I plan to bead blast the outer surfaces to prep for painting, paint all exterior surfaces a high gloss black, and (of course) design the front panel.






 YES, blue is my favorite color


----------



## Proutch

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Proutch, it is normal for the Transformer to be quite hot. During burn-in however you don't want to leave the amplifier unattended until you get a feel for how it is behaving. It's ok to carefully put your hand on the iron of the trafo, to see how it's doing. That is part of the characterization process. If it gets hot enough to create smoke, then there is a problem somewhere, otherwise just expect the 370 to run quite warm. The size of the enclosure also determines an amplilfiers ability to handle heat. You have built it into a beautiful, but small enclosure which means heat will take longer to dissipate. After the burn-in, running it for several days on and off, you should see that everything is fine. But don't worry as long as it sounds good and you see no smoke during this burn-in. Again, NICE WORK!_

 

OK thanks a lot for the advice, Amphead. The 370 runs hot, but no smoke so far.
 And after a few hours of music, the initial harshness has already 
 decreased - it probably came from the K701. Listening only gets better, and sound is getting really sweet. Can't wait for burn-in period to end (with my workdays, I can't spend more than a couple hours /day on it)

 @Dantes: difficult to plan in the coming weeks but it would definitely a good idea
 @Balderon superb case! Love it!

 Once again, thanks your comments - coming from you guys means a lot!


----------



## pabbi1

Wow, the overall quality of this build group is just spectacular, and on par with the best commercial offerings. I am truly proud for the association.


----------



## cgrums

What started as a spring break project has finally yielded results! I've gone through 2 amp boards (lifted traces), 4 voltage regulators and a great deal of sweat (no blood thankfully....yet 
	

	
	
		
		

		
		
	


	




) but my Bijou is finally alive!

 It's dead quiet and the sound is fantastic! I'm using Mundorf MCap Supreme's, Bugle Boy 6DJ8's and Russian 6N6Pi's...I've never heard a tube amp with this level of clarity. It's not cold but it's close (with Grado SR-60's); the SR-60's are usually a touch harsh in the treble for me but not with the Bijou. I'm looking very much forward to bringing the amp in to my office to listen with my Ultrasone Pro750's.

 The project is not quite done yet; I've cooked part of the power supply that I'm using to power a Jambo DAC that will be connected to my work computer via USB and then out to the Bijou...I also need to order a new front panel (or re-case the amp/DAC) as I rushed and messed the first one up.

 Thanks to all for the help in my troubleshooting!


----------



## Ferrari

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_
 YES, blue is my favorite color 
	

	
	
		
		

		
			








_

 


 If this is work in-progress, then the final work will undoubtedly be a looker.
 Nice work, balderon! 
	

	
	
		
		

		
		
	


	




[size=xx-small](as long as your amp is not going to look better than mine, of course)[/size]


----------



## runeight

It's really great for me to see all of these new (and really nice) Bijous. And, of course, it's always good to hear that they are all working. 
	

	
	
		
		

		
		
	


	




 Thanks to all of the new builders for giving the amp a try. I still love mine. There is just something about the way it sounds . . .


----------



## zkool448

balderon, looking sweeeet 
	

	
	
		
		

		
		
	


	




 Just got through stuffing my PS board, HV didn't smoke and good to go putting out 250V B+ with 100K load. Both coffee and solder still steaming, on to the amp boards and consider pulling an all-nighter see how much I can get done


----------



## jkroon

Go Zkool! Gitter done!! And nice job on that case Balderon. All of these nice cases make me ashamed of mine.


----------



## zkool448

Well the amp boards are stuffed. My tubes are the ECC99s and E88CCs, did regal's mod and mounted all tall caps on the underside of the amp boards. 

 I realized can't continue further until my navships wires arrive this week or next. I did however tried some 18 AWG (600v) wires from brother-in-law just to check the heaters operation -- happy to report all tubes lit up on power up with no smoke! I also connected the B+ out to the amp boards, and voltages are good and fully adjustable. The heater voltages from the windings are a bit on the high side though (7.02v) so may have to use a power resistor to drop some.

 Just panel jacks/pot/nfb wiring and I can almost hear the beautiful sound that comes out of it


----------



## TimJo

Way to go zkool !!! 

 Can't wait to see what it looks like when she's all cased up, but in the meantime maybe you should should attach the boards to a piece of ply and use the 18ga. and give it a listen... 
	

	
	
		
		

		
		
	


	




 Let's see - is the EHHA next?


----------



## zkool448

Lol thanks!

 All boards on standoffs laid out on an mdf plank covered with aluminum sheet, IEC/star ground bolted, and obbligatos hanging beneath the amps bellies -- sooo eager to get it all wired up you've no idea! 

 EHHA is also on the radar


----------



## funch

Just thought I'd chime in with some upgrades I've done to my 

 Blue Bijou.

http://i183.photobucket.com/albums/x...d/100_1838.jpg
 Replace all the amp board resistors with Holco/PRP.

http://i183.photobucket.com/albums/x...d/100_1839.jpg
 Replaced heater wiring with shielded SPC (in white).

http://i183.photobucket.com/albums/x...d/100_1840.jpg
 Replaced the Greyhill switch with an Elma from Parts Connexion,
 and the signal wiring is now Cardas litz (#21.5).

http://i183.photobucket.com/albums/x...d/100_1841.jpg
http://i183.photobucket.com/albums/x...d/100_1843.jpg
 Replaced the ebay stepper with a DACT from Headamp (a steal at $129).

http://i183.photobucket.com/albums/x...d/100_1842.jpg

 It still has a _very faint_ hum in the right channel, but nothing distracting.

 I'm amazed every time I listen to this amp. It is very revealing of the source,
 though. It deserves the very best source you can throw at it IMHO.


----------



## fishski13

funch,
 superb wiring skills, especially the SA. i thought your "original" was perfect. 

 is the DACT and Elma a worthy the price of admission?. i built a SA for my Bijou with the Electroswitch D-series - it's too "clunky" for my tastes, requiring some muscle and sticky fingers to turn over. i'm thinking i might just use a PEC carbon pot for my re-build. although, i really like the "feel" of the Series-71 Grayhill i installed for a source selector in a pre-amp/CK2III/y-1 i recently finished. 

 why the hum in the R-channel? any ideas? are you using an LED powered via the heaters? more specifics and maybe we can help?


----------



## funch

fishski13, thanks for the nice word.

 For me, the DACT was worth it, especially at the price Justin at Headamp
 is asking. The build quality, of course, goes without saying, and the action
 is as smooth as a baby's behind. Now that I've installed a DACT, I don't
 think I'll ever go back to using a pot on any higher end build, although
 as good as the Bijou sounds, I don't think I'll be doing that any time soon.

 The connectors on the DACT are Molex, and make connecting very easy.

 After I ordered the SA, I figured I might as well get the Elma to match.
 AFAIK it's the same as the DACT selector, but half the price.
 The Greyhill is no slouch, but the gold plated contacts on the Elma, along
 with its slightly smoother action just kick it up a notch. Worth the $ IMHO.

 I can't seem to pinpoint the cause of the R channel hum. It's extemely faint,
 and doesn't increase with changes in volume. It's so faint, in fact, that I 
 can't hear it if the AC in the house is on, so I'm not gonna worry about it.
 BTW, I'm not running LED's.

 Now that I've installed the DACT, I would like to drop the gain of the amp, 
 but don't know how to do that just yet. Time to bump up the learning curve.


----------



## DoYouRight

seems more and more people are getting ideas from the KrMathis B22 even for tubes now! Blue circle led power button etc


----------



## balderon

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_If this is work in-progress, then the final work will undoubtedly be a looker.
 Nice work, balderon! 
	

	
	
		
		

		
		
	


	



[size=xx-small](as long as your amp is not going to look better than mine, of course)[/size]



_

 

I wanted to thank everyone for their kind comments.

 Ferrari, thank you so much! Although I do aspire to achieve the level of excellence in style and design as your builds, I do try to raise the bar higher.


----------



## zkool448

*Another Bijou Lives!!* 

 Please forgive the temporary wiring mess but a rewire will be done once the proper wires arrive. I couldn’t wait for the navships wires (blame goes to Timjo, but glad I listened 
	

	
	
		
		

		
		
	


	




). 

 I admire all those who had built this amp since to me the biggest challenge is figuring out the layout and wiring. To manage to make your builds appear so effortless and neat, I’m now able to fully appreciate and grasp the amount of work and time put forth by all in building their Bijous.






 The amp sounds simply incredible. It has to be the best headphone amp I’ve ever owned. I simply can’t bring myself to put my headphones down and crave to get through my entire music collection. I’m astounded by how it sounds, the background is absolutely silent, spacious soundstage. Acoustics sounds shockingly detailed, exceptionally warm and smooth with excellent highs. The bass sounds incredibly deep with enormous slam … just a delight to listen to. 

 Thank you Alex, I’m absolutely WOWed by it.


----------



## nattonrice

Even without a case that is just... damn... wow! haha


----------



## pabbi1

Welcome to the club - good call on the Obbligatos. Is that the ubiquitous rk27? If so, you might have a future tweak of benefit there... 
	

	
	
		
		

		
		
	


	




 Yes, the soundstage is what is most unique - enjoy!


----------



## Ferrari

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_
 Ferrari, thank you so much! Although I do aspire to achieve the level of excellence in style and design as your builds, I do try to raise the bar higher. 
	

	
	
		
		

		
			



_

 

No objection here, I would love to see the final results! 
	

	
	
		
		

		
		
	


	









  Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_*Another Bijou Lives!!* 
_

 

Good to see you get your Bijou up and running. 
	

	
	
		
		

		
		
	


	



 Now put that amp in a nice enclosure. Knowing you, I'm sure it will be something beautiful.


----------



## funch

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_*Another Bijou Lives!!* 

 The amp sounds simply incredible. It has to be the best headphone amp I’ve ever owned. I simply can’t bring myself to put my headphones down and crave to get through my entire music collection. I’m astounded by how it sounds, the background is absolutely silent, spacious soundstage. Acoustics sounds shockingly detailed, exceptionally warm and smooth with excellent highs. The bass sounds incredibly deep with enormous slam … just a delight to listen to. 

 Thank you Alex, I’m absolutely WOWed by it._

 


 Welcome to the Bijou world. I couldn't have said it better myself.


----------



## TimJo

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_*Another Bijou Lives!!* 

 I simply can’t bring myself to put my headphones down and crave to get through my entire music collection. I’m astounded by how it sounds, the background is absolutely silent, spacious soundstage. Acoustics sounds shockingly detailed, exceptionally warm and smooth with excellent highs. The bass sounds incredibly deep with enormous slam … just a delight to listen to. 

 Thank you Alex, I’m absolutely WOWed by it._

 

I'm glad to read it was worth it zkool. 
	

	
	
		
		

		
		
	


	




 This way you can listen to the amp while you build your new wiring harness. 
	

	
	
		
		

		
		
	


	




 It will be interesting to see if you can tell a difference in sound quality when you upgrade it with the navships wire. I'm not sure if anyone has ever done that.


----------



## funch

An update on the R channel hum. I swapped the input tubes (6H30's) side to side, 
 and the hum seems to be gone. That was easy!


----------



## fishski13

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_An update on the R channel hum. I swapped the input tubes (6H30's) side to side, 
 and the hum seems to be gone. That was easy!_

 

good to hear. my 6N1P are temperamental as well.

 i have a couple more hours or so of running wires until my Bijou is back in action.


----------



## zkool448

Happy to be part of the club -- cheers!

 Went to the mailbox today and found a set of SPC teflon insulated wires from navship 
	

	
	
		
		

		
		
	


	




 Guess the rewire job is gonna happen sooner than I thought. Alex, since my Bijou is working perfectly (no hum, beautiful sound) I keep thinking about your signature that says "_Don't mess with anything that is working_"


----------



## runeight

Yes, but we all know that you'll have to do it anyway.


----------



## smeggy

hehe, I hope you're not as dangerous with a soldering iron as I am 
	

	
	
		
		

		
		
	


	




 talking of irons, I actually got round to buying a half decent Hakko 25 watt pro and very nice it is too, along with their copper swarf tip cleaning tub thingy. It's amazing the difference a good iron can make


----------



## dBel84

that is the utter truth smeggy, half the work can be fighting with an inadequate soldering iron. 

 great work balderon and zk , I miss not having one about to listen to..dB


----------



## wiatrob

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_For me, the DACT was worth it, especially at the price Justin at Headamp
 is asking. The build quality, of course, goes without saying, and the action
 is as smooth as a baby's behind. SNIP._

 

Very nice updates!

 I have the balanced version of the DACT in my EHHA - I have only had experience with RK's and EBAY SAs - the DACT is definitely worthy. I had heard about the 'chunkiness' of SAs but find the DACT to be quite smooth. I'm interested to try the Elma...


----------



## wiatrob

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_Happy to be part of the club -- cheers!

 Went to the mailbox today and found a set of SPC teflon insulated wires from navship 
	

	
	
		
		

		
		
	


	




 Guess the rewire job is gonna happen sooner than I thought. Alex, since my Bijou is working perfectly (no hum, beautiful sound) I keep thinking about your signature that says "Don't mess with anything that is working" 
	

	
	
		
		

		
		
	


	



_

 

I have been using milspec SPC/teflon for a while now (purchased a big surplus spool) and have been quite happy with it's quality and workability. 

 Can't wait to see what you're doing for _this_ builds's case... No rendering's to share?


----------



## zkool448

Quote:


  Originally Posted by *smeggy* /img/forum/go_quote.gif 
_talking of irons, I actually got round to buying a half decent Hakko 25 watt pro and very nice it is too, along with their copper swarf tip cleaning tub thingy. It's amazing the difference a good iron can make 
	

	
	
		
		

		
		
	


	


_

 

smeggy, you never had a decent iron all these years? I kept ranting to my wife about my crappy rat shack iron so she grabbed me a 936 for my bday a few months ago 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *dBel84* /img/forum/go_quote.gif 
_that is the utter truth smeggy, half the work can be fighting with an inadequate soldering iron. 

 great work balderon and zk , I miss not having one about to listen to..dB_

 

dB, I'm sure you can always build another, eh? 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *wiatrob* /img/forum/go_quote.gif 
_I have been using milspec SPC/teflon for a while now (purchased a big surplus spool) and have been quite happy with it's quality and workability. 

 Can't wait to see what you're doing for this builds's case... No rendering's to share?_

 

Good to hear the SPC wires are pretty decent, they do look and feel of high quality IMO. As for a build 'render', still contemplating what to do but I did post this mock up on another thread earlier.


----------



## balderon

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_



_

 

Looking good Joel. IMO the classic analog meters are the better choice. I am giving 10-1 odds you have already started the teardown for the wiring upgrade! 
	

	
	
		
		

		
		
	


	




 Thank you Don, I am surprised to hear you didn't keep a Bijou around. I'd imagine you have at least one amp somewhere that is comparable?


----------



## jdkJake

Quote:


  Originally Posted by *wiatrob* /img/forum/go_quote.gif 
_I have been using milspec SPC/teflon for a while now (purchased a big surplus spool) and have been quite happy with it's quality and workability. 

 Can't wait to see what you're doing for this builds's case... No rendering's to share?_

 

I second that opinion. The SPC/teflon wire navship sells is extremely high quality wire that is very easy to work with. Braids well and the teflon jacket is durable as all get out!

 jk


----------



## Proutch

Hey guys

 Just a quick post to tell you that my K701 and Bijou have finally burnt in and they sound superb!!!

 Sound is warm, detailed, balanced, dynamic, spacious, wonderful, beautiful!!!!!
 LOVE IT!















:k701s mile:


----------



## fishski13

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_Hey guys

 Just a quick post to tell you that my K701 and Bijou have finally burnt in and the sound superb!!!

 Souns is warm, detailed, balanced, dynamic, spacious, wonderful, beautiful!!!!!
 LOVE IT!
















:k701s mile:
	

	
	
		
		

		
		
	


	


_

 















:k701sm ile:

 both SE and Balanced, i've not heard my K701 sound better. the Bijou seems to be the perfect tonic for the K701's bass and treble characteristics. i will admit that it won't suit everyones tastes, but the musical abilities (yes, it's about the music, no?) of the combo is very tasty - equal in these abilities to my all-Naim kit i owned before. the 150uF/per channel Mundorfs get soldered in tomorrow night. i'm wondering if this will be enough for the K701 - i'm prepared to buy another 250- 300uF, but i have a stock pair of HD650 ready and waiting 
	

	
	
		
		

		
		
	


	




.


----------



## pabbi1

The Bijou with Senns is quite something, and 2x with the hd800, but the spacing of the Bijou with the spacing of the hd800 might be too much space, or, oddly, dual space overlay? 

 Building another amp (or two) for comparison, in quite different topologies.


----------



## fishski13

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_The Bijou with Senns is quite something, and 2x with the hd800, but the spacing of the Bijou with the spacing of the hd800 might be too much space, or, oddly, dual space overlay? 

 Building another amp (or two) for comparison, in quite different topologies._

 

why not learn the art of tubes? i learned a lot building the High Octane guitar amp for my friend in addition to the Bijou. the physics of a tube is pretty amazing; on par with attempting to track a vinyl groove with a pine tree needle 
	

	
	
		
		

		
		
	


	




. the Bijou is my reference, but i'm moving on to sand amps, that is until the StackerII is released 
	

	
	
		
		

		
		
	


	




.


----------



## pabbi1

Oh, I am all tube - it is the IRON that is now the passion. Let's just say I'm leaving Hammond behind for Lundahl with 6h30/6n23/ez81 on the one hand, and James / UTC with 307a/7w7/5v4 on the other... with maybe some 83/866a mercury vapor in the power section later on.

 We'll think of it as refined Euro vs brute force US military (well, with some Japanese engineering).

 I am leaving my working Bijou alone. Period.

 Alex mentioned somewhere he is working on a 'tweak' to the StackerII - some sort of, well, anomaly.

 Edit: Sand is so 4 years ago for me, but, Marc & company are tempting me with the (all sand) DynaFet. Must resist!


----------



## holland

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_the 150uF/per channel Mundorfs get soldered in tomorrow night. i'm wondering if this will be enough for the K701 - i'm prepared to buy another 250- 300uF, but i have a stock pair of HD650 ready and waiting 
	

	
	
		
		

		
		
	


	




._

 

Add 330uF. I don't notice many issues associated with a rolloff @ 480uF. There will be some distortion @ 10x the rolloff frequency, but I think that's around 30Hz and wouldn't be noticeable without measurements. I use Mundorf M-Cap as well, should have paid for some Supremes though. 

 Since we're talking caps, the M-Caps are OK, but looking for a bit more sparkle and bass. I was wondering if a bypass would work, and if so, what value and what brand? I could go for Silver/Gold but at what value? Obbligato? How about a Vit Q bypass, though I only have 0.18uf/600V.


----------



## holland

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_the Bijou is my reference, but i'm moving on to sand amps, that is until the StackerII is released 
	

	
	
		
		

		
		
	


	




._

 

No, EHHA love? I see you've got an M3 now. Nice amp, but you have to go B22. 
	

	
	
		
		

		
		
	


	




 I've got my 3-channel EHHA kit on the way, after I finish tweaking my SOHA II.


----------



## fishski13

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_No, EHHA love? I see you've got an M3 now. Nice amp, but you have to go B22. 
	

	
	
		
		

		
		
	


	




 I've got my 3-channel EHHA kit on the way, after I finish tweaking my SOHA II._

 

i just received a shipment from Mouser today and should have my B22 boards by the end of the week. i'm only building a 2-channel for now, but will add a third if i like it enough.

 the EHHA was on the radar, and i have a bunch of 6N1P lying around, but i've been wanting to build a B22 for awhile now.


----------



## zkool448

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_Just a quick post to tell you that my K701 and Bijou have finally burnt in and the sound superb!!!_

 

It's superb indeed! 

 Powered my Bijou back up after fully rewiring it last night and wow, the grandeur of all tube amp is back. Its airy presence, spaciousness, and music is presented in "3D". The Bijou’s sensual mids is hard to beat, bass drops deep, weighty. My build is silent and background is completely black. I thought amphead overstated where he could hear an ant piss at a 100 yards -- well he's absolutely right.

 Truly in love with the sound, relieved to finally found me a reference amp. All further builds are postponed indefinitely. Only plan now is to fund on more tubes and tryout boutiques and likely build another Bijou for my old dad (who by the way thinks his starving student is just the finest LOL - he's in for a treat)

 p.s. holland, I like the 1uF obbligatos wiatrob sent me for bypass.


----------



## fishski13

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Add 330uF. I don't notice many issues associated with a rolloff @ 480uF. There will be some distortion @ 10x the rolloff frequency, but I think that's around 30Hz and wouldn't be noticeable without measurements. I use Mundorf M-Cap as well, should have paid for some Supremes though. 

 Since we're talking caps, the M-Caps are OK, but looking for a bit more sparkle and bass. I was wondering if a bypass would work, and if so, what value and what brand? I could go for Silver/Gold but at what value? Obbligato? How about a Vit Q bypass, though I only have 0.18uf/600V._

 

i have a few Sonicaps that i'll probably try bypassing with after i've got a handle on the M-caps. i'm holding off on Regal's Mod and the Cardas wire as well.


----------



## wiatrob

Must...Not...Will...Not...build...Bijou! 
	

	
	
		
		

		
		
	


	




 Looking forward to hearing Naaman's at the Colorado meet later this month...


----------



## DoYouRight

Bijou is on par with B22 for tube sound? or EHHA?


----------



## adamus

no, its a very different amp to the B22. Its quite coloured, slightly slow..... but oh so lovely to listen too. I have not listened to a B22, but by reading reviews, it is none of the above.


----------



## zkool448

Quote:


  Originally Posted by *wiatrob* /img/forum/go_quote.gif 
_Must...Not...Will...Not...build...Bijou! 
	

	
	
		
		

		
		
	


	




 Looking forward to hearing Naaman's at the Colorado meet later this month..._

 

Do it..do it.. 
	

	
	
		
		

		
		
	


	




 Can't wait to hear some impressions after the meet, have fun!

  Quote:


  Originally Posted by *DoYouRight* /img/forum/go_quote.gif 
_Bijou is on par with B22 for tube sound? or EHHA?_

 

I’ve not had the pleasure to listen to either but I’m sure some lucky headfiers may have and maybe own all three who can tell you. Do recognize however that the Bijou and b22 belong in different class, for reasons that runeight explained quite well from a previous post that I read.

_edit:_ like adamus said, just like comparing a Rolls Royce to a Ferrari


----------



## TimmyMac

I've built both, but I don't have a common source to power them with since my B22 is a 4-channel build. Best I could do is compare 2-channel B22 to Bijou, and I will once I get my EZDac finished.


----------



## bhjazz

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Since we're talking caps, the M-Caps are OK, but looking for a bit more sparkle and bass. I was wondering if a bypass would work, and if so, what value and what brand? I could go for Silver/Gold but at what value? Obbligato? How about a Vit Q bypass, though I only have 0.18uf/600V._

 

The rule I always learned was for a bypass to be as high in voltage as the cap you are bypassing, and somewhere around 0.1. If this fits where you are dropping this into the circuit, I'd give it a try.


----------



## holland

ok, thanks. I've got some 0.1uf/160v MK1839 on order, which according to some sites help the M-Cap. I'll try it with the VitQ and will order a couple of different Obbligatos and possibly mundorf silver/oil and silver/gold. It's for the output coupling caps. 0.1uf helps me save money. I was wondering if it needed to be 10% of the value, but I guess not.


----------



## bhjazz

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_ok, thanks. I've got some 0.1uf/160v MK1839 on order, which according to some sites help the M-Cap. I'll try it with the VitQ and will order a couple of different Obbligatos and possibly mundorf silver/oil and silver/gold. It's for the output coupling caps. 0.1uf helps me save money. I was wondering if it needed to be 10% of the value, but I guess not._

 

Whoa, wait! 160V will not work. The Bijou runs at 250V! Caps rated at 250V would be the minimum. I thought you were going to use the 600V VitQs....which would be fine.


----------



## holland

Yeah, I'm going to try a number of different bypass caps. 160V should be fine, I think. 250V is the B+, but the output DC isn't at B+ level. It should be about 125V. 160V should cover it. I can measure the DC to be sure.

 The MKP1839 is only available in 160VDC. I have Vit Q 0.18uf/600V which I will try and I think the Mundorf S/O and S/G are at 1200V.


----------



## bhjazz

Good point! OK. As long as you are in the know about the voltage. I'd hate to be responsible for blowing some big-dollar caps in your house! Have fun, and do post your findings. I'd love to know how it all turns out.


----------



## holland

ugh, took my case apart to allow for bypass cap tweaking and took the opportunity to measure some voltages. My B+ has sagged *alot* to 229V. I now have it set to 225V for regulation. I did some quick measurements and my tranny is putting out 280V-0-280V (Rcore type), might have to do some debugging here, grrrr. 
	

	
	
		
		

		
			





 Not happy. /me starts to pull up the schematics.

 Will start some bypassing later, I guess.


----------



## holland

Alex, what is the output of the EZ81 supposed to be? I'm measuring 308VDC out of pin3. Pin 1 and Pin 7 differential measures 570VAC. Relative to CT, I measure ~285VAC.

 308VDC seems low to me. Drop across R7 and R8 are about 34.5VDC. I'm using Regal Mod with 6N1P input and 6N6P-i driver.

 Edit: 34.5VDC over R7 and 34.5VDC over R8, so about 70V drop total.
 Edit: Heater is 6.8VAC.


----------



## Ferrari

I’m not Alex and also too busy with this thing





, but just opened my Bijou, checked the voltage of my PS at pin 3 of the EZ81 and got ~315V. 308V at that point seems to be a bit low but acceptable I think (~2.5% off). 
 Is your measured heater voltage loaded or unloaded ?


----------



## holland

Thanks Ferrari, much appreciated.

 My heater voltage is loaded. Looking at the current across R7 and R8, it seems high at 105mA. Do you get similar? I'm going to warm up the amp and take pin measurements to see if I can find where the current is going.


----------



## zkool448

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_I’m not Alex and also too busy with this thing



_

 

Ferrari, whatever it is you're working on it looks brilliant already -- btw, what is it? 
	

	
	
		
		

		
		
	


	




 holland, not sure if this helps but I also have an R-Core and done regal's mod. EZ81 pin 3 mine measures at about 325VDC. I get 580VAC with meter leads on pin 1 & 7 (both at ~291VAC relative to CT). Heater voltage loaded but a bit high than I'd like which is at ~7.18VAC.

 Voltage drop readings for R7 & R8 total is 53.3vdc (R7 = 26.7vdc, R8 = 26.6vdc)


----------



## holland

What tubes are you using zkool448? I think one of my drivers went bad.


----------



## holland

Hmm, weird. Measuring Pin2 of the 6N6P-i on the right side pulls in about 79V. On the left, it's 113V. The left is steady, the right, as soon as I probe it, it drops down in voltage and settles around 79V. Something's amiss. I can't quite reach the 330n caps to measure the voltages on either side, and it's hard to probe the tubes as I have a bracket over the board to hold the tubes up.


----------



## holland

Thanks Ferrari and zkool. I replaced the 6N6P-i with 6N6P and it's steady now. I can hold 250v. It was a bad tube, guessing it's on the left side.


----------



## zkool448

Glad you found the problem holland. I fired up my Bijou once and also had wrong readings. Thought I fried one of my FETs then accidentally discovered the culprit after swapping the input tubes. 

 One of the socket pin hole had become loose/opened it wasn't making contact with the tube's cathode leg. Squeezed it back to shape and problem was solved. You might want to double check your sockets just in case your tube might still be ok.


----------



## Ferrari

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Thanks Ferrari and zkool. I replaced the 6N6P-i with 6N6P and it's steady now. I can hold 250v. It was a bad tube, guessing it's on the left side._

 

Good to know the problem is solved, holland.


  Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_Ferrari, whatever it is you're working on it looks brilliant already -- btw, what is it? 
	

	
	
		
		

		
		
	


	


_

 

It’s a tube amp… hehe. 
	

	
	
		
		

		
		
	


	



 Well, it’s a kind of tinkerman project, intend to be a transformer coupled one-stage tube amp to drive 32Ω/300Ω headphone.
 I have been playing around for a while with some high gain tubes 6S45p-E triode, D3a pentode (in triode mode) and 6N30P-DR dual triode + Sowter output transformer as one-stage amp with very good result (there are probably more tubes that's technically up for this task).
 So, I decided to put it in a neat enclosure instead of P-P wiring on my desk.

 On the left of the picture is the amp chassis. Due to the different pin layout of the tubes, I created some tube bases to make them exchange-able. The chassis on the right houses the DC power supplies: 6.3V heater and 150V/180V B+.


----------



## amphead

That is a beautiful looking project Ferrari! 

 Balderon NICE WORK! Keep us posted for the sound.

 Well I'm working on an underground laser light show for my nephews band. He will be playing at an underground club. This gives me my first chance to do a public light show. My green laser at 80mw is quite bright. The red laser at 325mw is pinkish/orange because of the power. And my 384mw ultraviolet/violet laser is a bright pink beam with bluish streaks because it causes dust particles in the air to become flourescent as well as the psychedelic posters in the club. Luckily they have invested in a fog machine.


----------



## fishski13

finally soldered in the M-caps, but now getting loud ground hum and tube microphonics in both channels. ohmed all the wiring out - measured fine, even the board mount Phoenix screw-connectors to J1. the attenuator measures fine as well with the input jacks. i even ohmed out the interconnects. my Bijou was working fine before inserting the M-caps. in addition to the caps, here's what i also did:

 -shortened and re-routed heater wiring.
 -sheilded B+ wire with screen grounded via red wire next to star ground since it is running over the heater wiring.
 -re-routed grounding wire; the R channel grounds run underneath the L channel board.
 -moved star-ground closer the PS board.

 my unsheilded signal wiring isn't perfect as i am going to try some Cardas and silver wire as well, but could this also be the problem? ground wires under the boards? btw, my R channel input wire off the attenuator is green, the L channel is red. 

 i'm glad i waited to tie in a bunch of cable ties to neaten-up/secure the wiring. 

 what am i missing here?


----------



## holland

Nice, soniccaps everywhere. I have M-caps everywhere, now bypassed with Vit Q for the output.

 What if you move the input wiring to the board? Does it change?

 On a different note, I noticed you have the voltage multiplier on, cool. I was just thinking about this some of this as I was looking over my PS recently. The loss of voltage seems to primarily come from the CRC filters. One can change the values to lessen the voltage drop across the filter, and get better ripple into the transistors, and give plenty of room for adjustment even if the EZ81 output drops to 305V, allowing more current pull.

 C6 - 68uF
 C4, C5 - 680uF
 R7, R8 - 220ohm

 Edit: oops, looks like C6 can be 50uF max. You'll get a bit more ripple with 47uF than with 68uF, but, OK...bummer.


----------



## fishski13

i'll try chop-sticking the wiring tonight. i also have a 2nd attenuator and a 100K pot i can try wiring in to rule out the present ground-shunt attenuator. i've looked over and ohmed my wiring multiple times...

  Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Nice, soniccaps everywhere. I have M-caps everywhere, now bypassed with Vit Q for the output.

 What if you move the input wiring to the board? Does it change?

 On a different note, I noticed you have the voltage multiplier on, cool. I was just thinking about this some of this as I was looking over my PS recently. The loss of voltage seems to primarily come from the CRC filters. One can change the values to lessen the voltage drop across the filter, and get better ripple into the transistors, and give plenty of room for adjustment even if the EZ81 output drops to 305V, allowing more current pull.

 C6 - 68uF
 C4, C5 - 680uF
 R7, R8 - 220ohm

 Edit: oops, looks like C6 can be 50uF max. You'll get a bit more ripple with 47uF than with 68uF, but, OK...bummer._


----------



## holland

cool, i was just wondering about the hum and the wire going over the caps. I'm not sure if it'll make any difference, but you hsould be able to just grab it and move it a bit and see if things change.

 I have my m-cap onto the case as well, using sticky tie points (I know, suckage, but I didn't feel like drilling bolt holes...lazy). You can try unhooking the cap and elevating it, to see if it changes on one side (i.e., stuff some packing foam underneath).

 I know my suggestions are borderline useless, but I don't really know what the problem may be.


----------



## fishski13

i wiggled the caps, signal and heater wiring with no change in buzz/hum.

 when i turn off the amp, the buzz/hum disappears immediately.

 i shorted the inputs to ground and the buzz/hum is still there. so the input wiring and attenuator are still suspect.


----------



## fishski13

i forgot i had originally done Amphead's mod, removing R9, R10 and C7, but forgot to wire in heater virtual CT 100R resistors to star-ground for the re-wire. all is well now and sounds great!!! 
	

	
	
		
		

		
		
	


	




.


----------



## chobint

Funny, I expected the 220uf caps to be a scale version of the 330's. Instead it appears they are a short, fat version. That is they appear to be of the same diameter, just a bit shorter.

 Anyway, looks good. Keep us posted.


----------



## chobint

double post


----------



## fishski13

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_Funny, I expected the 220uf caps to be a scale version of the 330's. Instead it appears they are a short, fat version. That is they appear to be of the same diameter, just a bit shorter.

 Anyway, looks good. Keep us posted._

 

actually, they're only 150uF.

 i've only had about an 1 hr on them, but will get a late night session session in tonight. with the HD650, i've already noticed a not-so-subtle improvement. i haven't tried the K701 yet.


----------



## holland

glad you found the problem, fishski13.

 I'm not sure I like the VitQ bypass of the M-Cap too much. It's added a different character. It's too "tubey" with some sparkle. It seems to change the 6N1P into more like the 6DJ8, but with more high end. I'm thinking I might get some FT3l, and replace the VitQ. I think I'll skip the Mundorf Silver/Oil and Silver/Gold. Too expensive!


----------



## fishski13

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_glad you found the problem, fishski13.

 I'm not sure I like the VitQ bypass of the M-Cap too much. It's added a different character. It's too "tubey" with some sparkle. It seems to change the 6N1P into more like the 6DJ8, but with more high end. I'm thinking I might get some FT3l, and replace the VitQ. I think I'll skip the Mundorf Silver/Oil and Silver/Gold. Too expensive!_

 

yeah, it only took 4 hrs. of trouble-shooting and discharging caps to realize i'm getting older and so is my memory (i turn 34 today). thanks for taking the time to help me out.

 i have no issues dialing in B+ with the cap multiplier and EZ81 - as it should be, but have yet to up the current of the input and phase splitter stages with Regal's mod. if i want to run DC heaters, i'll need a dedicated filament TX. the heaters are dead quiet now though...why bother? i wish i had a scope, just for curiosities sake. 

 i'm using 0.47uF Sonicap Gen I for bypass: Sonicaps

 and here's a comparison vs. Gen II:
Sonicap Gen 2

 it's nice to have the Bijou back. thus far, the M-caps are a bit more "grippy" - it handles and hugs the curves a bit better. i'm finishing up touches on my FPE face-plate as a B-Day gift for myself. the Bijou has been a long WIP. i've completed 3 big projects since i've last worked on the Bijou. i have boards and parts for a 2-channel B22 in front of me, but have unfinished business with the Bijou. thanks Alex for designing such a wonderful music maker.


----------



## zkool448

34? fishski you're still a pup 
	

	
	
		
		

		
		
	


	




 Thought I'd share some progress with my Bijou front plate. The vu meter is not the final unit and will be replaced by this with a blue backlight (courtesy of zare):


----------



## fishski13

zkool,
 looks great! i like the blue VU meters


----------



## fishski13

those of you with M-caps: did you notice any significant burn-in?


----------



## holland

I didn't notice significant burn-in, but I had some. I didn't particularly keep track but I think somewhere around 72 hours or so. I leave the amp on 24/7 after builds always to check operating parameters. It was about 3 days for me, but subtle if any. I run 330uF + 150uF. Bass came up a bit. YMMV.


----------



## chobint

330 + 150 = 480uf of pure poly cap goodness??? Man you went all out 
	

	
	
		
		

		
			





 Anyway, I donno fishski. The initial change with the caps was really the only significant difference in the amp's sound that I was able to appreciate, besides rolling between JJ 6922 and some old 6dj8 tubes. Other than that, all the other mods haven't yielded any significant results for me. So, as for burn in? I couldn't say. I think it's more likely that the initial wow factor wore off rather than an actual change in the sound. Unlike speakers, which are mechanical and susceptible to an increase/descrease in physical pliability with extended use (ie burn in)... I'm not sure if I believe in electrical components being susceptible to break in.


----------



## holland

Quote:


  Originally Posted by *chobint* /img/forum/go_quote.gif 
_330 + 150 = 480uf of pure poly cap goodness??? Man you went all out 
	

	
	
		
		

		
		
	


	


_

 









 0.1uF MKP1839 bypass of the M-Caps, digging it so far. Very nice. Much nicer than the Vitamin Q.


----------



## jERiCOh

Hey guys!
 After a couple months listening to my starving student I decided to get back to the bijou I started earlier. Got pretty much everything to finish the build beside the tubes and the output caps. While shopping for an EZ81 I found those Weber Copper Cap. Does someone tried it ? 
 I'll try to post some pictures of my WIP later.


----------



## TimmyMac

Why not just use an EZ81?


----------



## jERiCOh

They claim that by not requiring filament power transformer runs cooler... Does it means a 270DAX could feed pretty much all the tubes combinations on a Regal moddded bijou without needing to modify the PSU circuit ?


----------



## holland

It uses solid state rectifiers with resistors to simulate the drop of the EZ81 at current loads with a relatively soft ramp up (not as soft as the EZ81). That's why there is no heater.

 You can use it. You can probably have a custom one built with less of a voltage drop at max load. It looks to be the same price. A 10V drop at max EZ81 load will probably be better, if you're going this way.


----------



## jERiCOh

Thanks for your reply. I think I'll order the "real" EZ81 and keep the solid state as a backup solution. 

 Does anyone could recommend a good output cap? I'm out of budget for MKP's because I'm driving grados. I remember pabbi1 was using photoflash caps... How does it compares to others like JJ's, Rifa's, Nichicon PW's and such ?

 There is a pic of what it starts to look like:


----------



## zkool448

Looks like you're all prep'd and set to go! Sorry no recommendation for output caps (I still have kit stock) but yes, MKPs silver/oil caps are good choice. I have obbligatos as bypass and quite happy with them.

 Whch input/driver tubes do you plan to use? I just got a pair of Bugle Boy 6DJ8s and they sound nice, vocals are most enticing I've heard compared to my other input tubes.


----------



## holland

Quote:


  Originally Posted by *jERiCOh* /img/forum/go_quote.gif 
_Thanks for your reply. I think I'll order the "real" EZ81 and keep the solid state as a backup solution. 

 Does anyone could recommend a good output cap? I'm out of budget for MKP's because I'm driving grados. I remember pabbi1 was using photoflash caps... How does it compares to others like JJ's, Rifa's, Nichicon PW's and such ?_

 

That's alot of caps dude. You should be all set. 470uF is good, more if you can. Zout of amp is not 0 neither, which should affect the output cap as well.


----------



## whitelabrat

Jericoh,

 I've had good luck with a single 100uF Solen cap at the output, where I use headphones from 100 ohms to 600 ohms. I've also tried a massive 600uF ASC film cap and couldn't discern the difference. I got the latter at $5 a pop as surplus.

 If you want to go the single film cap route for the output, you'll probably want at least a 160uF for those 32 ohm Grados. More if you can afford it.


----------



## jERiCOh

Well for the output caps, I think I'll go for cheap Nichicon PW while leaving some room in the case for a MKP upgrade.
 As for the tubes, I'm planning tu use the default Regal mod ECC99/6922. I want that amp to work at first and then later I'll work on improvements.
 I will post more pics as the work progress.


----------



## amphead

Photoflash caps are a great sounding low cost solution. Experimenting with other caps is good too, don't feel pressured or boxed in to just one way of building.

 Good to hear that the resistors fixed that for you Fishski!

 Nice panel work Zkool!

 I'm working on a secret project at the moment. Pics when it's done.


----------



## fishski13

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_Photoflash caps are a great sounding low cost solution. Experimenting with other caps is good too, don't feel pressured or boxed in to just one way of building.

 Good to hear that the resistors fixed that for you Fishski!

 Nice panel work Zkool!

 I'm working on a secret project at the moment. Pics when it's done._


----------



## holland

Quote:


  Originally Posted by *amphead* /img/forum/go_quote.gif 
_I'm working on a *secret project* at the moment. Pics when it's done._

 






 Super Bijou lives?


----------



## breizheau

I have almost finished the Dynalo (waiting for encoder for control volume that i broke..... 
	

	
	
		
		

		
		
	


	




 ) and will work again on the balanced Bijou. I received wires from Navship and have almost finished to populate the PCB.... 
	

	
	
		
		

		
		
	


	




 The 2 customized irons are at home, i just have to find time ! 
	

	
	
		
		

		
		
	


	



 But after reading all the post, i can't wait to listen to it....


----------



## jERiCOh

Same for me. I was working at fisrt on the Mauro Penasa's My Ref Rev C (speaker chipamp) and I got more involved on the Bijou than my current project. The tubes are soooo appealing. Getting my Chipamp done today then I'll be able to get back to that beauty.


----------



## zkool448

Quote:


  Originally Posted by *breizheau* /img/forum/go_quote.gif 
_.. and will work again on the balanced Bijou. I received wires from Navship and have almost finished to populate the PCB.... 
	

	
	
		
		

		
			





 The 2 customized irons are at home, i just have to find time ! 
	

	
	
		
		

		
		
	


	



 But after reading all the post, i can't wait to listen to it.... 
	

	
	
		
		

		
		
	


	


_

 

git r done guys


----------



## breizheau

I just have to find time......


----------



## balderon

My Bijou has been disassembled for a couple weeks to add my latest (and hopefully) final round of upgrades. I didn't realize the physical size of the Mundorf MKP caps when I originally developed the case. Unfortunately I'll have to redo most of the case to gain the 1/2 inch needed to fit these monsters under the covers. I am pondering what can I build next and reuse my old case! 
	

	
	
		
		

		
		
	


	




 I am looking forward to the day I can once again listen to this great amp.


----------



## fishski13

balderon,
 the Mundorfs are worth every penny. i'm only using 150uF/channel, but w/HD650 i find the bass to be perfect.


----------



## balderon

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_balderon,
 the Mundorfs are worth every penny. i'm only using 150uF/channel, but w/HD650 i find the bass to be perfect._

 

fishski13, I am anxious to get humpty dumpty back together again! Did you experience any changes or improvements in SQ after initial powerup/burnin?


----------



## fishski13

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_fishski13, I am anxious to get humpty dumpty back together again! Did you experience any changes or improvements in SQ after initial powerup/burnin?_

 

i maybe have 50 hrs or so on the caps - i haven't detected any burn-in. 

 with the Mundorfs, music sounds "tighter" and more focused. dynamics are a little more obvious, with a cleaner, leaner, punchier bass (note: i'm only using 150uF). trebles and transients are a little sharper as well.

 i love the pairing with the HD650. with the K701, if i had to choose between the 150uF film and the 470uF 'lytics, i'd go back to the 'lytics. the mids and trebles are wonderful, but zero bass. i need to decide if i want to lay out cash for more Mundorfs. right now, i have an M3 that suits the K701 nicely. i'm also antsy to build a preamp/B22 and a bridged Nelson Pass F5 i've been slowly accumulating parts for over the last 3 months.

 i'm also playing around with wire with the Bijou. i just recently added a PEC pot to my M3 and hardwired in some old Chord Co. wire, with no input RCA jacks and plugs at the amp - pot or hardwiring, i don't know - but it was nice improvement. i much prefer my Jupiter solid silver/cotton wire and Furutech rhodium plugs with the Bijou over the decent copper i have lying around. i'm going to hardwire some 1m silver wire to the SA in the Bijou as well. but first...

 i'm soldering Regal's Mod this weekend. i'll have a whole week off of work to get some relaxing HP time in, and check out a couple of new albums.


----------



## rolotube

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i maybe have 50 hrs or so on the caps - i haven't detected any burn-in. 

 with the Mundorfs, music sounds "tighter" and more focused. dynamics are a little more obvious, with a cleaner, leaner, punchier bass (note: i'm only using 150uF). trebles and transients are a little sharper as well.

 i love the pairing with the HD650. with the K701, if i had to choose between the 150uF film and the 470uF 'lytics, i'd go back to the 'lytics. the mids and trebles are wonderful, but zero bass. i need to decide if i want to lay out cash for more Mundorfs. right now, i have an M3 that suits the K701 nicely. i'm also antsy to build a preamp/B22 and a bridged Nelson Pass F5 i've been slowly accumulating parts for over the last 3 months.

 i'm also playing around with wire with the Bijou. i just recently added a PEC pot to my M3 and hardwired in some old Chord Co. wire, with no input RCA jacks and plugs at the amp - pot or hardwiring, i don't know - but it was nice improvement. i much prefer my Jupiter solid silver/cotton wire and Furutech rhodium plugs with the Bijou over the decent copper i have lying around. i'm going to hardwire some 1m silver wire to the SA in the Bijou as well. but first...

 i'm soldering Regal's Mod this weekend. i'll have a whole week off of work to get some relaxing HP time in, and check out a couple of new albums._

 

I've had a similar experience with Tubecaps. 200's on the output firmed up the sound significantly with HD650's, without sacrificing bass extension. I wouldn't go back to electros now except perhaps for low impedance phones. The 701's just don't work with my Bijou the way it is now (no NFB probably doesn't help), but I reckon its close to ideal for the Senn's.

 There were no obvious burn in effects with any of the new caps (Tubecaps throughout PS & at the output, Supreme Silver/Oil for coupling), just a slight mellowing of the sound; or perhaps it was me getting used to it? But any effects may also have been masked by constant tweaking. Shinkoh resistors have certainly helped & it is still improving with these - increased spaciousness, depth & overall clarity. All signal wiring is Jupiter or Audio Consulting solid AG, input jacks are ETI Phonopods. 

 Biggest change has come however from a pair of Bugle Boy 6DJ8's (1962) - a staggering improvement. I now understand why such a fuss is made about these tubes. The last tweak has been a HiFi Tuning fuse & I kid you not, it HAS made a difference! Improved focus & clarity of the soundstage as well as a slight tightening of the bass were the obvious changes.

 This is now undoubtedly the best amp I've ever heard. I find it hard to get enough of its liquid, mellifluous, MUSICAL sound. Once again, I'm rediscovering my music collection & marvelling at the detail & musicality that many CD's can offer.

 I'm waiting on some parts from Jeff Rossell to finish the SOHA II I've started, but I suspect it won't be in the same class as the Bijou.


----------



## holland

Try a bypass of the Mundorf with the MKP1839. It's cheap @ Mouser. That has really woken it up for me and has made me not notice the veil on my HD650 (I'm one of those that find it a bit stifled), but YMMV. My tastes are clearly different. I prefer the 6N1P, I don't much care for the Bugle Boy 6DJ8 or the A-frame 6DJ8. It's too thick. I found the Mundorfs a bit soft up top, but the MKP1839 seems to have cured that for me. I haven't tried the Obbligato coppers or golds yet.

 SOHA II vs Bijou. Class, hmm, not sure. I find it hard to classify amps in categories like that. It's different for sure. Mine is no longer stock and running at Bijou type voltages (ha! to the stacker guys ) and using some tubes, I forget which exactly but it's an ECC82 that was recommended sometime back. Bijou is what I would say is more "liquid". The SOHA II is edgier and more raw. As with tubes, much of the sound varies with it. If using low-Z, I would lean more towards the SOHA II.

 I haven't built my EHHA yet (taking a break and just enjoying music), but from the raves, it sounds like that is one to keep an eye out for.


----------



## zkool448

Hi guys, yes! it's finally done!

 Thanks for all your help everyone and especially to Alex 
	

	
	
		
		

		
		
	


	









 More pics of my build at the build gallery. Cheers!


----------



## chobint

Wow, well let me be the first to say... that looks fantastic. That is probably one of the most beautiful bijous I've seen built on head-fi. I dare say that its one of the few that gives Ferrari a run for his money : D


----------



## fishski13

zkool,
 absolutely stunning. i have a huge appreciation/respect for your chassis DIY/woodworking abilities. if my B22 looks half as good as your Bijou, i'll be pleased. 

 like you need to worry about what style of VU meter you should go with 
	

	
	
		
		

		
		
	


	




. no matter what, it will be a work of art.

 kudos!!!


----------



## Dantes

Wow ! Beautifull casing !
 Very impressive !


----------



## runeight

Agreed on that case zkool. You have a very unusual viewpoint on amp design. 
	

	
	
		
		

		
		
	


	




 Is the amp working ok?


----------



## zkool448

Many many thanks guys 
	

	
	
		
		

		
		
	


	




  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_You have a very unusual viewpoint on amp design. 
	

	
	
		
		

		
		
	


	




 Is the amp working ok?_

 

lol It works flawless Alex, you're the man 
	

	
	
		
		

		
		
	


	



 It sounds exactly as it did, perhaps even better than first time I gave it a good listen. cheers!


----------



## sachu

You are nuts man. That is just outta this world. Stunning piece of work. 

 Now that is a masterpiece!


----------



## Ferrari

Zkool448, I knew you are busy with something beautiful, but this is just far above my expectation.
 Excellent work… I like the originality!!!


----------



## rolotube

Can only agree with the above. Well done a superb build.


----------



## zkool448

once again, many thanks guys. 

  Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Zkool448, I knew you are busy with something beautiful, but this is just far above my expectation.
 Excellent work… I like the originality!!!_

 

Ferrari, just illustrating the possibilities of what can be done and hope to inspire others to build one of their own, just as I watch your builds as my greatest motivation.

 To receive such compliment from someone like you who builds some of the *BEST* cases around here acknowledge my work is remarkably flattering.


----------



## Proutch

Zkool, this is absolutely stunning! Wonderful!

 Commercial products don't look that good


----------



## holland

wow, that's insanely beautiful, zk. The amount of work you put into the cases is just astounding. The coloring is great. What wood and paint did you use? I really wish I was able to do things like that.


----------



## adamus

zk, any chance of a youtube of the vu meters bouncing?


----------



## zkool448

cheers guys 
	

	
	
		
		

		
		
	


	




 holland, it's the same mdf build you saw earlier at the casework thread. Aside from many hours of sanding, it only took a can of primer and a can of high heat silver metallic paint to finish.

 adamus, will post one up a quick clip a week from today when I return from vacation!


----------



## fishski13

finally got around to soldering in Regal's Mod, but have some odd voltage readings.

 with B+ = 250V, i'm reading 158V at pin6/phase splitter input of the my 6N1P. R3=30K.

 walking through some maths...

 voltage drop across R3: 250V-158V= 92V
 current at pin6: 92V/30K= 3.1mA

 Regal speced the idle current at 5mA and according to the Tweaks page at cavalliaudio.com, i should be getting around 100V at pin6.

 in my PS, i have the cap multiplier mod, TX is 370DAZ, and rectifier tube EZ81.

 -as it stands now, is my PS "safe" to run at 3.1mA? i have yet to plug in my headphones for a listen.
 -if i want to crank up the idle current, do i need another transformer, and how would i go about doing this?


----------



## runeight

It seems like your PS is doing fine.

 What cathode resistor are you using for the first stage?


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_It seems like your PS is doing fine.

 What cathode resistor are you using for the first stage?_

 

cathode resistor/R2 = 1.5K per your specs for a 6N1P. but with Regal's Mod...can i/should i lower it. i should be able to get more idle current with lowering it...no? up or down 
	

	
	
		
		

		
		
	


	




good thing i socketed R2.


----------



## runeight

Aha. Go back to the Regal mod Bijou page and scroll down to the bottom. 
	

	
	
		
		

		
		
	


	




 Socketing R2 is a good idea. 
	

	
	
		
		

		
		
	


	




 Hopefully this will give you the correct voltages.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Aha. Go back to the Regal mod Bijou page and scroll down to the bottom. 
	

	
	
		
		

		
		
	


	




 Socketing R2 is a good idea. 
	

	
	
		
		

		
		
	


	




 Hopefully this will give you the correct voltages._

 

doh...i can't believe i missed that chart 
	

	
	
		
		

		
		
	


	




. i know i have a bunch of 182R in the parts bin. thanks Alex!!!


----------



## royalflush

Quote:


  Originally Posted by *zkool448* /img/forum/go_quote.gif 
_





 More pics of my build at the build gallery. Cheers!_

 

Hello. I am a long-time lurker here so I briefly know of some of you. I am incredibly inspired to say the least, particularly when looking at zcool's builds. Ultimately I have decided that I will DIY my next amp.


----------



## fishski13

Regal's mod is done 
	

	
	
		
		

		
		
	


	




. sounds great. highly recommended. 

 at pin6, i'm getting 114V in one channel and 103V in the other - a difference of 0.4mV. B+ is 250V. anything i should bother with?


----------



## runeight

Probably not. It's close enough for tubes. If you want you can try to reduce the value of R2 on the 114V tube. Maybe 175R if you can find one. But, if everything sounds good, I'd leave it alone.

 Also, although the website says to use ECC99 with Regal's mod, your PS will handle the 6N6Ps too.


----------



## Forte

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_ Also, although the website says to use ECC99 with Regal's mod, your PS will handle the 6N6Ps too. 
	

	
	
		
		

		
		
	


	


_

 

Does this mean anyone can use 6n6p with Regal's mod, and if not what further modifications need to be made?


----------



## runeight

No, unfortunately.

 IIRC, fishski is using a special PS with cap multipliers substituted for the two filter R/C sections. The multipliers have a very small voltage drop and a constant voltage drop for any current that the Bijou can draw. Hence fishski can do almost anything and his B+ will stay at 250V because the input to regulator will stay well above 250V.

 The PS mod is quite a few pages back. I can post the schematic again if you'd like to see it.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Probably not. It's close enough for tubes. If you want you can try to reduce the value of R2 on the 114V tube. Maybe 175R if you can find one. But, if everything sounds good, I'd leave it alone.

 Also, although the website says to use ECC99 with Regal's mod, your PS will handle the 6N6Ps too. 
	

	
	
		
		

		
		
	


	


_

 

thanks Alex!


----------



## Forte

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_No, unfortunately.

 IIRC, fishski is using a special PS with cap multipliers substituted for the two filter R/C sections. The multipliers have a very small voltage drop and a constant voltage drop for any current that the Bijou can draw. Hence fishski can do almost anything and his B+ will stay at 250V because the input to regulator will stay well above 250V.

 The PS mod is quite a few pages back. I can post the schematic again if you'd like to see it._

 


 No need thanks, found it! http://www.head-fi.org/forums/4869555-post1601.html

 Probably should get on and build my Bijou first before thinking about any mods 
	

	
	
		
		

		
		
	


	




 Did the P/S add on boards ever get made or does this need to be done on perf board?


----------



## runeight

No, we never did make a PCB. Only a few folks were interested.


----------



## whitelabrat

I've been putting some serious hours on my Bijou lately. It gets about 2-6 hrs of use everyday where I keep it in the office. Just the other day I heard a bit of a "fftht" sound and the feedback on one channel died. I'm guessing R12 on one channel gave up. Are there any negative implications other than not having feedback anymore?

 Note to self. No more 1/8w resistors.


----------



## runeight

Running without NFB is perfectly alright, especially if you listen with high Z phones.

 However, R12 doesn't really pass any current. 1.8W should be ok here. If R12 is really fried this could be indicative of another problem. One that has not so far been reported.

 Please let us know what has actually happened.


----------



## amphead

If you run high Z phones, I would recommend leaving out the NFB. If you think you will sometimes use low impedance phones then a little NFB wouldn't be too bad.

 Kudos Fishski on the Regal mod!


----------



## zkool448

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_zk, any chance of a youtube of the vu meters bouncing?_

 

Here's a short video clip of the Bijou with jlm vu buffers in action. Pls forgive the poor audio sq due to camcorder mic input. 

_(click link in case embedded video does not work)_


+ YouTube Video​ _*ERROR:* If you can see this, then YouTube is down or you don't have Flash installed._


----------



## pabbi1

Very nice Joel - color me jealous.


----------



## bhjazz

Wowee. That's one smart-looking Bijou, zkool. Very nice!


----------



## royalflush

*drool* very unique build zcool a one of it's kind.


----------



## regal

Quote:


  Originally Posted by *Forte* /img/forum/go_quote.gif 
_Does this mean anyone can use 6n6p with Regal's mod, and if not what further modifications need to be made?_

 

I switched to the russian tubes with no further mods other than what was listed for the EC99's, the PS can handle it and the ruskies sound bettter.


----------



## holland

I'm using 6N1P, and 6N6P with Regal's mods. I can't regulate to 250V. I believe I'm set for 245V. There's too much voltage loss in the tube rectifier and the CRCRC filter. Keep an eye on the voltage over time, especially after it warms up for a few hours. There are tube variations, so some may and some may not have issues.

 Cap multiplier drops less voltage, as does the choke mods (I believe).


----------



## runeight

Yes, either the choke mod or the cap multipliers will maintain the voltage. It appears that some, but not all of the tubes pull a bit too much current, more than expected.

 If I were designing the PS today I would use the cap multipliers and then no one would have regulation issues. I avoided them initially so that the amp would be as much "tube" as possible, including the older style RC filters. The only concession was the fet regulator. However, given that the RC filter is behind the regulator, it may as well be more sand.


----------



## fishski13

the cap multiplier mod is cheap and easily done on veroboard - although i wouldn't recommend air-wiring it (attached photo is my first ill-fated attempt at air-wiring transistors in my original balanced Bijou for everyone to have a chuckle at 
	

	
	
		
		

		
		
	


	




). 

 if you have the space, it's easier to mount the cap multiplier off the PS board. i mounted it on the PS board, but it wasn't terribly difficult.

 it's been awhile since i've heard my Bijou balanced, but Regal's mod definately improves on the dynamic abilities of the SE amp. much larger and bolder imagery too. 

 if anyone who wants to up the idle current of the input stage and add Regal's mod to an existing Bijou, do yourself a favor and buy a solder-sucker if you don't already have one. i assumed that fitting the larger 1W and 2W leads into the pcb pads might get tricky, so i ordered one of these from my local friends at Digikey: Digi-Key - K500-ND (OK Industries/Div of Jonard Ind Corp - DP-140). i'm glad i did. getting those thicker leads in was tricky. the best i could do was get one lead end all the wat through the pad hole, and the other, only half-way through the hole. i used Yageo resistors: Digi-Key - 30KW-2-ND (Yageo - RSF200JB-30K). i had a difficult time sorting through the lead diameters of various manufacturers' datasheets. YMMV.


----------



## fishski13

also, one should increase the heatsinking on Q2 of the PS with the cap multiplier. see here: http://www.head-fi.org/forums/f6/bij.../index122.html

 and once again...thanks to Regal for his contribution.


----------



## Forte

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I switched to the russian tubes with no further mods other than what was listed for the EC99's, the PS can handle it and the ruskies sound bettter._

 

 Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Cap multiplier drops less voltage, as does the choke mods (I believe)._

 

 Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yes, either the choke mod or the cap multipliers will maintain the voltage. 
 If I were designing the PS today I would use the cap multipliers and then no one would have regulation issues._

 

 Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_the cap multiplier mod is cheap and easily done on veroboard 
 if you have the space, it's easier to mount the cap multiplier off the PS board. i mounted it on the PS board, but it wasn't terribly difficult._

 

 Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_also, one should increase the heatsinking on Q2 of the PS with the cap multiplier._

 


 Wow
	

	
	
		
		

		
		
	


	




, thanks to all who replied, much appreciated.

 Finally started my Bijou, soldered the P/S board last night, after the CTH I was surprised by just how few parts there are and how much room on the board there is. Will go with stock build for now, then when finished and I know everything is working will see if the P/S needs modding since results seems to vary. 

 The cap multiplier seems the way to go, but I don't think I am going to have enough room or the skills to make one on veroboard. Will have to see what parts are available locally first and then take it from there.

 If I go with a choke supply which variation on the website is preferred?

 And how big do I need to go on the Q2 heatsink, the one I have is 2" tall and I can't go taller, will that be enough?


----------



## runeight

Both choke supplies will do the same think, but variation 2 is a bit easier to do. You just eliminate R7, R8, and C5 and insert the choke leads into the right pads for R7 and R8.

 A 2" heatsink should be enough. The fet will get hot though.


----------



## Forte

Well the choke idea is out, hadn't realized how big the choke was, no room.

 If I mount the cap multiplier off the PS board how far away can it be?


----------



## holland

Heh, I have the same problem with space, but really running @ 245V is no big deal for me.

 I thought of 2 approaches. Changing the CRCRC filter to reduce the drop (reduce R, increase C). Using 220ohm instead of 330ohm resistors and increasing the big Cs to 680uF, for example. I think ripple is a bit worse off, not sure, haven't really looked at it beyond that.

 Using a semi-conductor bridge instead of a tube rectifier will definitely work. I think you can use one of the copper caps in place of the EZ81 and have it custom made by that company. I can't recall who though. It's simple internally, just using R's to emulate the voltage drop and create a soft-start situation (not as soft as the EZ81). If you make your own, you can use a thermistor.


----------



## Forte

holland - If I can get 245V then I will probably go with that as well. My space problems are vertical, I have room horizontally for the cap multiplier but on the wrong side of the P/S board, will play around with the layout I have planned and see if I can swap the board around.

 Since you are using the same Rcore transformer what is the best way to use the two sets of 6.3V secondaries? I had planned to use one for the P/S board and the other for the amp boards to keep things simple, is there a better way?


----------



## holland

Forte, I put them in parallel and added a pair of series resistors to drop the AC voltage down some. Paralleling is easy, connect the center taps, that will create a reference point in the middle and you can probe the wires with a DMM to see which wires to connect.

 One thing to note, unless you do Amphead's heater mod, is that the heater is biased at some relative DC level. So parallel would be best for the stock configuration without Amphead's heater mod. Though I think if you keep the center taps connected together you can wire them separately. I haven't thought much about that. It was easiest for me to use a single heater configuration as it required less resistors to tweak the voltage.


----------



## fishski13

Quote:


  Originally Posted by *Forte* /img/forum/go_quote.gif 
_holland - If I can get 245V then I will probably go with that as well. My space problems are vertical, I have room horizontally for the cap multiplier but on the wrong side of the P/S board, will play around with the layout I have planned and see if I can swap the board around.

 Since you are using the same Rcore transformer what is the best way to use the two sets of 6.3V secondaries? I had planned to use one for the P/S board and the other for the amp boards to keep things simple, is there a better way?_

 

i wouldn't worry about the distance of wiring the cap multiplier to the PS board. others smarter than me please chime in, but i don't think any relatively small extra lengths in the PS circuit would be an issue with respect to noise or resistive DC output.


----------



## fishski13

anybody,
 how do i calculate the output impedance of the Bijou into a known load, both on paper and in situ DVM readings? i have no NFB.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_
 A 2" heatsink should be enough. The fet will get hot though._

 

Forte,
 i used this heatsink for Q2 with the cap multiplier mod: Digi-Key - HS386-ND (Aavid Thermalloy - 531302B02500G)


----------



## runeight

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i wouldn't worry about the distance of wiring the cap multiplier to the PS board. others smarter than me please chime in, but i don't think any relatively small extra lengths in the PS circuit would be an issue with respect to noise or resistive DC output._

 


 Yes, a little bit of extra wire won't matter here as long as it's not too long.

 Fishski the Zo of the Bijou is about 55R with no NFB.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yes, a little bit of extra wire won't matter here as long as it's not too long.

 Fishski the Zo of the Bijou is about 55R with no NFB._

 


 thanks!!!, but how do _I_ go about getting 55R?


----------



## runeight

Ah. I did this calculation quite a while ago and I don't remember how to do it again, but the output impedance is given by:

 Zo = rp / (2 * (1 + mu))

 The ECC99 has an rp of 2300R and a mu of 22 so ...

 Zo = 2300 / (2 * 23) = 50R

 The 6N6P has an rp of 1800R and also a mu of 22 so ...

 Zo = 1800 / (2 * 23) = 39R

 In this configuration, with the crossed outputs from the phase splitter, both O/P triodes operate as cathode followers. So the Zo is essentially the paralleled Zo of two cathode followers.


----------



## fishski13

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Ah. I did this calculation quite a while ago and I don't remember how to do it again, but the output impedance is given by:

 Zo = rp / (2 * (1 + mu))

 The ECC99 has an rp of 2300R and a mu of 22 so ...

 Zo = 2300 / (2 * 23) = 50R

 The 6N6P has an rp of 1800R and also a mu of 22 so ...

 Zo = 1800 / (2 * 23) = 39R

 In this configuration, with the crossed outputs from the phase splitter, both O/P triodes operate as cathode followers. So the Zo is essentially the paralleled Zo of two cathode followers._

 

thanks!


----------



## rolotube

Anyone tried the Reflektor 6H23P-EB? Appears to be a Russian low-noise military spec variant of the 6922.


----------



## Forte

Have tried the regular 6h23p tube, got one in a batch of 6n1p by mistake. Prefered it to the 6n1p IIRC (haven't listened to it in a long while)

 Edit - This was in a CTH(getting threads mixed up)


----------



## rolotube

Thanks. All reports I've seen where these have been used in other amps have been positive. Got some coming this week so I'll find out soon enough.


----------



## Proutch

Hey guys,

 Just sharing my recent experience with the Bijou: I replaced the ECC8 with vintage Orange Globe Amperex tubes made in Holland.
 And I must say the improvement is drastic! Sound is much cleaner, more transparent, slightly tighter, still sweet and full.

 In case you're still running the stock tubes, this is clearly worth the investment!

 I must say I had a hard time to chosse between Orange globes and Bugle boy. The latter get so much positive comments, including in this thread. At the same time, they look slightly overpriced because of their reputation and Orange Globes were made in the same factory, and should sound very similar.

 This being said I'd be very curious to compare my Orange Globes with Bugle boys...
 Has anyone had a chance to do so?


----------



## regal

I also found the orange globes to be a better match to the Bijou than the bugle boys. I don't know if its because most average bugle boys on ebay are spent or if there is some technical reason. Lets hope these two posts dontt drive the orange amperex price up.


----------



## rolotube

I've had a set of Bugle Boys in for a few weeks now & have been extremely happy, especially as I got them for a very reasonable price. The Orange Globes were also available but were very little cheaper, so I went for the BB's largely on reputation. But I remain curious as to the differences between the "classical" old 6JD8 variants. Given their relatively high cost & increasing scarcity, it may take some time & quite a few $$'s to work through them all.

 I'm currently enjoying something different; Reflektor 6N23P-EB, dated 1986. Just put them in tonight & initial impressions are extremely favourable. Not as full & rounded as the Bugle Boy, more "in your face" & analytical perhaps, but very musical. Bass is more solid, mid & upper mid not quite so forward. Maybe not quite the same expansive soundstage & 3D imaging the Euro tubes are famous for. And absolutely dead black quiet. They may possibly be a slightly better match for my rig than the Bugles. I'm running all film caps (no electros) including Silver/Oils & Jupiters so the sound may be bit "softer" compared to stock. Early days yet but I'm very impressed, especially as they were less than $50 for a matched pair.

 As Proutch highlights, the stock tubes are OK but there's much to be gained in trying the many different types that the Bijou design permits.


----------



## kansei

I set my mind on building a Bijou in December. My initial plan was to resell some tubes on eBay to make $ for the kit. I ended up getting distracted buying and selling on eBay for about 6 months until I finally decided to order the kit. 

 Last year I had no tubes and no tube equipment. I now own 4 tube testers (3 Hickok and 1 Eico), a bunch of tube amps, bunch of testing equipment and a few thousand tubes. I'm not sure what happened. 
	

	
	
		
		

		
			





 First Bijou impressions: 
 - sounds incredible, it squeezes every bit out of the music you play
 - Diana Krall, Dido, The Cardigans, wow
 - this amp really drives my HD600s, bass response is terrific
 - it really worked, even the first time, yay!
 - needs burning in

 I first used the "cheapo" GE 6dj8 tubes, then switched to the Bugle Boy tubes. I have other 6922 tubes, will have to try a few different sets. 

 Building impressions:
 - it was easy to solder together, took no time at all
 - my brain went into a spasm when the time came to wire it together, had to power through wiring it together
 - I mounted it on a shabby 12x8 chassis that used to belong to an old Lafayette PA amplifier (that was left in someone's basement for too long). 
 - I'm afraid to post pictures because it looks awful
 - it's time to buy a nice Hammond chassis
 - now I need another project, rats


----------



## runeight

That's great Kansei. I'm glad you like the sound. Still one of my favorite amps.

 Since I'm a real old-time, I kind like the chassis. Reminds of long, long ago. But, you'll probably be happier when it's in something that you like better. 
	

	
	
		
		

		
		
	


	




 As for another project, far be it for me to suggest, but you could try either the SOHA II or the EHHA. Both a fun amps and are each quite different from Bijou. There are threads here on headfi dedicated to both amps.


----------



## kansei

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_That's great Kansei. I'm glad you like the sound. Still one of my favorite amps.

 Since I'm a real old-time, I kind like the chassis. Reminds of long, long ago. But, you'll probably be happier when it's in something that you like better. 
	

	
	
		
		

		
		
	


	




 As for another project, far be it for me to suggest, but you could try either the SOHA II or the EHHA. Both a fun amps and are each quite different from Bijou. There are threads here on headfi dedicated to both amps. 
	

	
	
		
		

		
		
	


	


_

 

I had a good amount of anxiety finishing this project. I wanted to get the amp up and running and kept hitting roadblocks with wiring it together. Finally, I decided to just hack it as best as I could and fix it later.

 Don't get me wrong, I like the chassis, it is very "old school" (that's why I decided to use it). What I need to do is to take it all apart, then polish the chassis and neaten the wiring.

 This is the first time in months I've had a working headphone rig, the clean-up will wait until I get something else up and running.

 SOHA II is on my list, one of these days.


----------



## rolotube

kansei, good to learn of another Bijou up & running with a satisfied owner/builder. I'm still knocked over with sound every time I fire mine up.

 As for other projects, I can heartily recommend the SOHA II. I've just finished mine (first iteration, anyway) & am very satisfied with the results.


----------



## kansei

I ran my Bijou overnight after I first built it. The second time I wanted to use it it would not work. It turns out that R5 in the power supply flamed out. I had to hack up a replacement since I don't have an exact value (ran four 80k resistors in parallel). Still, the replacements are running super hot.

 I have 2 questions:
 - when adjusting the power supply, is it absolutely essential to put the 100k resistor over over the 250v output and GND? I adjusted mine without it and it appeared to be OK
 - is it possible that my power supply is incorrectly adjusted and that's why it blew out the R5?

 Thanks.


----------



## runeight

Kansei, it is very possible that your PS is not working right. Measure the B+ with the amp boards connected. My guess is that you will not read 250V. Usually this is caused by a short to the PS (even briefly). This, in turn, causes the mosfets to die and when the do lots of current is passed through R5. However, R5 is spec'd at 1W to handle this condition so that even if the fets go out R5 will survive. But if R5 is toasted too, the PS is surely gone.

 Sorry to for this news, but I think this is correct. However, please measure the B+ and tell us what is says. 

 Thanks.


----------



## kansei

I assume that B+ is the output voltage of the power supply, marked 250v and star ground. If my assumption is correct, I get 103v on B+ with both of the amp boards connected and 250v with the boards disconnected.


----------



## runeight

Correct. I'm sorry to say that 103V indicates that both of your mosfets have died and have to be replaced. When you do that it would be good to check other components in the PS and replace R5 with the right size if you have it.

 It is very difficult to protect a high voltage supply against shorts without going to a lot of expense. The Bijou HV supply is simple (and cheap), but it can be blown.

 However, my supply is more than 3 years old now and it still regulates. So, normal power-up and power-down do not cause the PS to die. Only short circuits or massive overloads.


----------



## runeight

Kansei, I meant to add that when I was building my prototype I shorted the PS 3 times and had to replace the mosfets 3 times too!!! I discovered just how easy it is create even a very brief short on the regulator when testing. When I tried to think of a way to add protection to the PS I realized it was going to be much more expensive than it was worth.

 And then once I stopped fooling around inside the PS, the regulator has been stable. So hopefully, you'll only have to replace the fets once.


----------



## rolotube

Is it possible to use 6N6's safely with regal's mods? There's a comment in the Tweaks section that indicates ECC99's should be used. Is this because the 6N6's draw too much current & may stress the PS?

 Any thoughts or experiences would be welcome.

 Thanks.


----------



## diego

Will a 270dax overheat if I use it at 120v? If it overheats could I just put a 1.5 ohm resistor in the primary to drop those extra 5v?

 Thanks.


----------



## holland

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_Is it possible to use 6N6's safely with regal's mods? There's a comment in the Tweaks section that indicates ECC99's should be used. Is this because the 6N6's draw too much current & may stress the PS?

 Any thoughts or experiences would be welcome.

 Thanks._

 

Yes, though you may have to regulate below 245V. I have mine @ 240V.


----------



## runeight

Quote:


  Originally Posted by *diego* /img/forum/go_quote.gif 
_Will a 270dax overheat if I use it at 120v? If it overheats could I just put a 1.5 ohm resistor in the primary to drop those extra 5v?

 Thanks._

 

diego the 270dax should not overheat running at 120V. These transformers are pretty durable.


----------



## rolotube

Quote:


  Originally Posted by *holland* /img/forum/go_quote.gif 
_Yes, though you may have to regulate below 245V. I have mine @ 240V._

 

Thanks holland. I'll given them a go & check out the voltage.


----------



## disco

Nice chassis Kansei. Next a nice wooden enclosure to finish it?

 I'm looking for a schematic of an all tube headphone amplifier and found the Bijou. Being reluctant to reinvent the wheel, I wonder why the headphones are coupled through an outputcapacitor. Is it because of financial reasons the outputtransformer is replaced?


----------



## runeight

disco, the Bijou is what is called an Output Transformerl Less (OTL) amplifier. Transformers tend to limit the output bandwidth of an amp and so, over the years, many designers have sought to eliminate them.

 The capacitor in the Bijou is needed because the output point (between the two triodes) is at 125VDC. The capacitor blocks the high DC voltage while passing the AC signal.


----------



## disco

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_disco, the Bijou is what is called an Output Transformerl Less (OTL) amplifier. Transformers tend to limit the output bandwidth of an amp and so, over the years, many designers have sought to eliminate them.

 The capacitor in the Bijou is needed because the output point (between the two triodes) is at 125VDC. The capacitor blocks the high DC voltage while passing the AC signal._

 

Sorry if I didn't make my point clear 
	

	
	
		
		

		
		
	


	



 I do own a pair of 4K:300 OT (BW -1dB >30KHz, so no restrictions there) and am looking for a circuit to build. Large output caps do not seem attractive to me...


----------



## runeight

The Bijou will have a much higher frequency response than your transformers. But, there are differences of opinion on how much this matters to the SQ. 
	

	
	
		
		

		
		
	


	




 And I think you might find that the capacitor is less limiting than the transformer.

 But, since you have transformers, there have been quite a few designs posted in various places for making a transformer output headphone amplifier. I wouldn't recomment using the Bijou's futterman topology with a transformer because this type of amp is specifically designed to be OTL, but some of these other designs, IIRC, are pretty nice. I don't have a pointer to any of them at the moment, but I suspect that you've seen many of them already.


----------



## disco

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_The Bijou will have a much higher frequency response than your transformers. But, there are differences of opinion on how much this matters to the SQ. 
	

	
	
		
		

		
		
	


	




 And I think you might find that the capacitor is less limiting than the transformer.

 But, since you have transformers, there have been quite a few designs posted in various places for making a transformer output headphone amplifier. I wouldn't recomment using the Bijou's futterman topology with a transformer because this type of amp is specifically designed to be OTL, but some of these other designs, IIRC, are pretty nice. I don't have a pointer to any of them at the moment, but I suspect that you've seen many of them already. 
	

	
	
		
		

		
		
	


	


_

 

Using an OT in an OTL would be contradictory, wouldn't it? 
	

	
	
		
		

		
		
	


	



 The reason for me posting here is to find a circuit. Perhaps other folks are lazy looking for them selves but the only not-OTL design I came across is the one from  Simon Busbridge. 

 That's why I made the remark wrt the OT. Not only do I _know_ that the output capacitor is much more offending to the actual reproduction quality of the amplifier than a good quality OT, it's more a matter of design principle. Financial reasoning would be a valid design choice though.


----------



## runeight

OK. I'm not sure that I can be of any further help except to note that the Bijou was designed as an OTL amplifier just because I had some ideas about doing one with a very simple power supply. There were no financial considerations involved regarding transformer cost vs. capacitor cost.

 Perhaps others on this thread can suggest places to find OT amplifiers that might give more selection.


----------



## pabbi1

So far afield, but look at the Raven in my sig, as well as the 307a - both balanced opt designs (though on the 307a, I'm NOT using a phase splitter on input as I have a balanced source). Pete also has a raft of designs on his site, which might be more in line with what you are seeking.


----------



## disco

Yes indeed, Peter has a lot to share 
	

	
	
		
		

		
		
	


	







 I'm using something similar to his srpp design. Looking for a way to loose the 10uF coupling cap though.
 Thanks for the input.


----------



## runeight

Great. Now that you've found something that you're interested in building you should start a new thread around this topic. There might be others who will participate if they see a new thread that is not buried down in the Bijou discussion.


----------



## Proutch

Following up on my previous post about tubes, I finally was finally lucky enough to get Bugle boys on ebay for cheaper than the Orange Globes (euro/dollar exchange also helps 
	

	
	
		
		

		
			





)

 My impression is that the Orange Globes have a larger spectrum and sound somewhat tighter, while the Bugle boys have a round finish and noticeably adds "air", setting a wide and natural soundstage.
 Classical and accoustic music already sounded gorgeous with Bijou+K701. With the Boys, it makes the experience totally live!

 Both are very musical pair of tubes, providing detailed and balanced sound, each with its personnality, although not totally dissimilar

 Two very good options, anyway.



  Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_Hey guys,

 Just sharing my recent experience with the Bijou: I replaced the ECC8 with vintage Orange Globe Amperex tubes made in Holland.
 And I must say the improvement is drastic! Sound is much cleaner, more transparent, slightly tighter, still sweet and full.

 In case you're still running the stock tubes, this is clearly worth the investment!

 I must say I had a hard time to chosse between Orange globes and Bugle boy. The latter get so much positive comments, including in this thread. At the same time, they look slightly overpriced because of their reputation and Orange Globes were made in the same factory, and should sound very similar.

 This being said I'd be very curious to compare my Orange Globes with Bugle boys...
 Has anyone had a chance to do so?_


----------



## runeight

Interesting results Proutch. One thing I noticed about my Bijou immediately, even with ordinary 6dj8s, was the feeling of being in a live hall. I get the same sense nearly every time I listen to it.


----------



## adamus

try bugle boys alex, there is definately some magic with the bijou. 

 amzing sense of space and image: bugle boy 6dj8
 most natural sound: 8416 (only if you have mess with ps wiring, 12.6 heaters).


----------



## Cellsplicer

I'm a bit late to the party but I've finally wired up my bijou (all stock parts). It really is something else and has revealed a completely new side to my ATH-AD900s! I regret not completing it a bit sooner as I've been busy with Uni and all for the past year and a half.

 This is my first amp build and previously I have been driving my AD900s off a X-Fi Prelude. I now know that a sound card doesn't do justice for these cans - I've noticed that switching to the Bijou has unlocked the lower end, widened the soundstage and the high end rolloff is no longer there. I'm now considering a pair of K702s but don't know how much I will like them. Quite happy with bijou+AD900 already!

 I'll get back in about a week when I have this baby inside a chassis


----------



## regal

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_Following up on my previous post about tubes, I finally was finally lucky enough to get Bugle boys on ebay for cheaper than the Orange Globes (euro/dollar exchange also helps 
	

	
	
		
		

		
		
	


	




)

 My impression is that the Orange Globes have a larger spectrum and sound somewhat tighter, while the Bugle boys have a round finish and noticeably adds "air", setting a wide and natural soundstage.
 Classical and accoustic music already sounded gorgeous with Bijou+K701. With the Boys, it makes the experience totally live!

 Both are very musical pair of tubes, providing detailed and balanced sound, each with its personnality, although not totally dissimilar

 Two very good options, anyway._

 

I prefer the orange globes, but the bugle boys are nice if you get good ones. Most of the bugle boys I found on Ebay were near death. My only gripe with the amp is that the tubes are so expensive so you can't leave it on all the time. I am envious of those who have modded to the 12V Amperex's which are cheaper and give much more bang for the buck vs. the 6V amperex's.


----------



## MoodySteve

I'm finally wiring up my Bijou and I'm seeing something unexpected for the power supply test.

 When I put a 100k resistor across the B+ terminals, I cannot for the life of me get the resistance between the terminals to actually read 100k. It usually reads about 30M initially and steadily climbs down but never really settles. Normally I'd attribute this to the meter but this is the only instance of it behaving this way; if I disconnect one of the legs with the meter still attached, it will instantly read 100k.

 I have screwed the resistor into the terminal block in multiple configurations and the resistor is now soldered in - I don't think I have an intermittent connection.

 Anyone else run into anything like this?

 Update: So, after an incredibly stupid wiring error (I managed to hook up the PS board to the transformer in precisely the opposite sequence that I was supposed to - terminal block was mounted on bottom of the board blah blah blah) C7 provided some spectacular fireworks. R10 appears to be intact, despite the fact that I calculated around 1W dissipation in the relatively short time it was powered on. Everything passes visual inspection, and I don't see any reason that the regulators would have gotten whacked. Alex (or anyone else) is there any other part I should ensure is still working before making my order for replacement parts? In particular, I'm concerned that I hooked up 260VAC to the heaters of the EZ81 - would you expect that rectifier to be toast?

 This was also my first time blowing up a capacitor (hard to believe) so I'm a bit sheepish right now...


----------



## runeight

LOL. Sorry. But I've had my share of these fireworks. Things like this just happen. 
	

	
	
		
		

		
		
	


	




 It's really hard to say what might have toasted because of this. If you wired up exactly opposite then you would have put 240VAC across the EZ81 heater. Probably a goner, but you can measure the resistance to see if you even have continuity or whether the heater is an open circuit. If it's not open it might still work.

 The bigger problem is that you also would have put 240VAC onto the ground traces and this is where it's hard to know.

 However, if nothing but C7 exploded I'd just buy extra mosfets and zeners. Everything else has probably survived.


----------



## runeight

Quote:


  Originally Posted by *Cellsplicer* /img/forum/go_quote.gif 
_I'm a bit late to the party but I've finally wired up my bijou (all stock parts). It really is something else and has revealed a completely new side to my ATH-AD900s! I regret not completing it a bit sooner as I've been busy with Uni and all for the past year and a half.

 This is my first amp build and previously I have been driving my AD900s off a X-Fi Prelude. I now know that a sound card doesn't do justice for these cans - I've noticed that switching to the Bijou has unlocked the lower end, widened the soundstage and the high end rolloff is no longer there. I'm now considering a pair of K702s but don't know how much I will like them. Quite happy with bijou+AD900 already!

 I'll get back in about a week when I have this baby inside a chassis 
	

	
	
		
		

		
		
	


	


_

 

Cellsplicer, good to hear another Bijou has come alive. The Bijou has a kind of of tube beauty to its sound. I still love to listen to it. And my proto is not as good as your amp.


----------



## MoodySteve

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_LOL. Sorry. But I've had my share of these fireworks. Things like this just happen. 
	

	
	
		
		

		
		
	


	




 It's really hard to say what might have toasted because of this. If you wired up exactly opposite then you would have put 240VAC across the EZ81 heater. Probably a goner, but you can measure the resistance to see if you even have continuity or whether the heater is an open circuit. If it's not open it might still work.

 The bigger problem is that you also would have put 240VAC onto the ground traces and this is where it's hard to know.

 However, if nothing but C7 exploded I'd just buy extra mosfets and zeners. Everything else has probably survived._

 

Thanks Alex. I do recognize that blowing up caps is a rite of passage - I'd just prided myself on building for years without such an incident. Oh well, no more of that for me! 
	

	
	
		
		

		
		
	


	



 I measured just shy of 1Ω between the EZ81 heater pins - the same reading as the extra EZ81 that wasn't the victim of my wiring. It looks like I got lucky on this one.

 Oh well, time to send Mouser some more of my money...it's been a few weeks; they're probably getting worried.


----------



## kansei

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_Oh well, time to send Mouser some more of my money...it's been a few weeks; they're probably getting worried. 
	

	
	
		
		

		
		
	


	


_

 

I sent Mouser around $30 after I blew up the mosfets on my Bijou. Of course, I had to buy multiples because I knew that Murphy's law would have struck if I just bought exactly as many as I needed. The Bijou is all aces now! Now, back to chassis work...


----------



## Chaos4

Hello All,

 I just wanted to say a quick "Thank You" to Alex for an absolutely fabulous design! I was able to turn my Bijou on for the first time last night and was truly amazed. I don't have a golden ear or anything, but this is one of the best amplifiers I have ever heard. I would also like to add it is dead quiet, another thing that is is pretty hard to find on other designs. Now to finish up a few consmetic issues....

 Thanks again!


----------



## runeight

Thanks!!! Glad you like it.

 After a few hours or running you might test the B+ and reset it to 250V. But be careful so you don't short anything.


----------



## rolotube

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_try bugle boys alex, there is definately some magic with the bijou. 

 amzing sense of space and image: bugle boy 6dj8
 most natural sound: 8416 (only if you have mess with ps wiring, 12.6 heaters)._

 

Agree completely. I've tried 6922, 6H30, 6N1P, etc but IMO nothing provides the space, air & soundstage of the Bugle Boys. The sound is amazing. I got mine from pcx; as far as I can tell they are unused, NOS in perfect condition, dated 1962 in generic white box. 
 BTW, 6N6P's worked well. B+ dropped from 250 to 248.7 but could easily be adjusted back up using the trimpot. Everything ran a bit hotter indicating a higher current draw. Still prefer the ECC99/Bugle Boy combo in my Bijou. Nothing comes close.


----------



## balderon

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_Still prefer the ECC99/Bugle Boy combo in my Bijou. Nothing comes close._

 

I have the same combo as your setup. I have often considered rolling to 6N6P's. Can you elaborate on why you prefer the ECC99?

 Thanks


----------



## regal

I prefered the 6n6p/BB vs the ec99/BB. Also upping the current on the bugle boys really helps.


----------



## balderon

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Also upping the current on the bugle boys really helps._

 

I am always interested in trying mods that improve the SQ. Have you bumped the current beyond your previous "Regal Mod"? If so, could you please share what resistor values you're using?
 Thanks


----------



## adamus

you can go as far as the PS will let you, which isnt that far.


----------



## balderon

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_you can go as far as the PS will let you, which isnt that far._

 

I was having difficulty maintaining the 250v B+ once I installed the "Regal Mod". I then installed a larger transfo. Now my PS has no problem maintaining the 250v and has a fair amount of reserve power. The Bijou is the first tube amp I have built and I currently don't possess the indebt knowledge needed to ensure I do not burn something out (especially my expensive BB's) 
	

	
	
		
		

		
			





 I certainly would like to find time to educate myself on that subject someday. Until then I rely on the expert knowledge of many members of this forum.


----------



## rolotube

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I have the same combo as your setup. I have often considered rolling to 6N6P's. Can you elaborate on why you prefer the ECC99?

 Thanks_

 

That's difficult. Best way I can put it is that the sound seems more spacious, detailed & 3D with ECC99's. But I've had the BB/ECC99 combo running for >50 hrs so they are well burnt in. The 6N6P's weren't in for anywhere near this long (a few hrs max) so I may be jumping the gun on their potential. I recall others as well as regal commenting that the 6N6's were better in their rigs. To be fair, I should give them a longer audition before passing judgment.

 I'm also running the higher current mods for the BB as suggested by regal. I think this has "livened up" the sound a bit compared to stock. 370DAX, choke PS mods & all film caps (no electros) in the PS probably also provide some extra reserve current & improved filtering.

 Its probably completely irrational, but I'm besotted with the BB/ECC99 combo in my Bijou & find it hard to be satisfied with the sound of any other tubes. Everyone's build is different so what works for me won't necessarily work for everyone (?anyone) else.


----------



## adamus

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I was having difficulty maintaining the 250v B+ once I installed the "Regal Mod". I then installed a larger transfo. Now my PS has no problem maintaining the 250v and has a fair amount of reserve power. The Bijou is the first tube amp I have built and I currently don't possess the indebt knowledge needed to ensure I do not burn something out (especially my expensive BB's) 
	

	
	
		
		

		
		
	


	




 I certainly would like to find time to educate myself on that subject someday. Until then I rely on the expert knowledge of many members of this forum._

 

A great place to start is Morgan jones "valve amplifiers". Teaches all the basics and is a fairly easy read. Would thoroughly recommend.


----------



## bhamham

Hey everybody!

 I'm finally building my Bijou.... got my kit months ago but other things kept getting in the way. 
	

	
	
		
		

		
		
	


	




 Anyway, there wasn't any LED1s in my kit so I searched the thread and a few have taken them out with D7. Is that the way to go?


----------



## adamus

If i remeber correctly, its the diode and led from the heater circuit you remove.


----------



## bhamham

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_If i remeber correctly, its the diode and led from the heater circuit you remove._

 

Thanks adamus, that's the ones.

 Almost got my boards done. I'll post some pics soon if I work up the courage - there's some amazing looking Bijous on this thread!

 First time I've ever done something like this.


----------



## amphead

We are waiting for the Pics. Good news on your progress.


----------



## balderon

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_A great place to start is Morgan jones "valve amplifiers". Teaches all the basics and is a fairly easy read. Would thoroughly recommend._

 

Thanks adamus. I'll check it out.


----------



## mugdecoffee

So I've tried searching through this thread without finding an explicit answer. Can you do do the Regel mod with a 270DAX or does the transformer need to be upgraded to support the higher current?


----------



## runeight

Most of the time you shouldn't have to upgrade the transformer. But the PS was not designed for handling this much current and you may find that the B+ pulls down some below 250V. If this happens you can dial the B+ down to 240V. The amp won't really notice the change.

 Or you can try the cap multiplier solution that was created earlier in the thread.

 Hopefully, yours will work with no issues.


----------



## Cellsplicer

It's now 99% complete. Just waiting for the knobs to get delivered


----------



## runeight

Looking really good. The knobs will polish it off nicely.

 When I see the pics you guys post I remember why I haven't ever posted pics of my prototype.


----------



## regal

Does anyone have instructions/part numbers to convert the Bijou to use the cheaper 12V Amperex tubes? I couldn't find a transformer in the Hammond catalog. I've also forgetten the Amperex part number for the 12DJ8.

 Another issue is my output caps are these huge motor run oils and I can't find a clamp big enough to secure them standing up.


----------



## adamus

the 12v tube is the 8416. 

 Most of the people who have used this are using the R-core tranformer as it has two lots of heater secondaries, in series they produce 12.6v. I suppose you would have to string another tranformer in series with the orinigal hammond.


----------



## fishski13

Quote:


  Originally Posted by *Cellsplicer* /img/forum/go_quote.gif 
_It's now 99% complete. Just waiting for the knobs to get delivered 
	

	
	
		
		

		
			













_

 

looks awesome!!! love the rocker switch too.


----------



## ntrl

Hi All!

 I ordered from Jeff Bijou Kit and now select chassis. But
 don't know size of PCB boards. 
 Please measure your PCB boards of Bijou.

 Thanks.


----------



## MoodySteve

ntrl,

 Amp boards are 3.4" x 2.6" with the mounting holes ~0.15" from the edges.

 Power supply board is 4.5" x 3.8" with the mounting holes ~0.20" from the edges.

 Diameter of mounting holes is around 0.140" (probably 6-32 clearance).


----------



## jkroon

Been awhile since I last posted. I connected my Bijou to the computer and watched a blu-ray in Dolby headphone surround. Holy crap does it sound awesome! Very clean, very 3 dimensional sound. I kept taking my headphones off to make sure the sound wasn't coming from the surround sound speakers. My surround sound receiver has been collecting dust for the last 3 months. The only trouble I've had with this amp is that I didn't account for any ventilation in the chassis. After it's been powered up for a couple hours it gets noisy because of the heat build up. For a temporary fix I just have the cover propped up to keep it from overheating. I'll have to take it apart to cut ventilation holes in the lid. But, I have a question. After hearing this amp I am no longer happy with the sound of my receiver. Is there any way to build this amp on a larger scale to power a pair of stereo speakers?


----------



## runeight

jkroon, nice to hear this. 
	

	
	
		
		

		
		
	


	




 The amp does get pretty hot and does need lots of air. However, it can't be turned into a speaker amp. 

 Which probably means that you should start looking into tube amps. Not all of them destroy your wallet, although there are quite a few that do.


----------



## chobint

Use it as a pre-amp. Thats what I do now »: )

 That said... having transitioned to using two separate speaker setups, I'd like to warn you before you plunge a bunch of money into upgrading your amplifier and speakers. Do some research. Proper speaker positioning, room resonance and managing wall reflections is very important with speakers. So for example, if you live in one of those apt. flats with all brick/concrete walls... your headphones will probably sound leaps and bounds better than a speaker setup because of sound reflections (to generalize). Try moving your speakers to all different positions before you drop a big wad on new gear.

 Now, that said... if you have the money, then goforit woo....

 On a sorta related note... Alex, I know you mentioned designing a speaker amp about 6mo-1yr ago. I was just wondering if this was still something in the works or if it was just ultimately a pipe dream?

 cheers,
 chob


----------



## runeight

I have at least two speaker amps ready to be pushed out but I'm currently focued on the stat amp.

 I'll get back to these some day.


----------



## chobint




----------



## gabriel-dan

Cellsplicer,
 It looks beautiful nice job. Do you have pics of the inside of the amp?


----------



## rille2

My Bijou is finished:










 I had some problems with hum. The reason where the ground wires. Some of them were too close to the transformer. I rerouted the ground wires and made a new star ground point far away from the transformer and the hum was gone. The little PCB helped much dealing with all the cables from the transformer.


----------



## GeWa

Nice build.
 That small circuit board is indeed cool and handy.
 Did you made that yourself?

 Regards


----------



## rille2

I made the design and ordered the PCB from a PCB manufacturer.


----------



## fishski13

rille2,
 beautiful!


----------



## viction

I just finished assembling the boards for my Bijou using a glassjar kit. This is my first project so I'm going to need a lot of help finishing this! I built my boards with the caps underneath so that the tubes can be outside of the enclosure. The amp boards were easy, but the power supply was tricky. The heatsinks were mounted underneath so they are dangling off of the mosfets pins. Will this be ok, or should I mount them back on top where they were originally?

 What are some nice aluminum enclosures available? Can you guys also recommend me RCA jacks, a phono jack, a nice power switch, and a power connector and cable? Thanks!


----------



## xxbaker

viction - The case I'm using is a Hammond Aluminum case that measures 8x12x3 in. It's a pretty good fit. I got all my jacks and switches from mouser.com, I'm sure other people will have other suggestions.


 Everyone - I finished putting everything together and noticed that my two 6h6n tubes don't light up. The three other tubes do. I measured heater voltage and it reads: 6.5VAC across the tube pins. That's a little high, could that be causing a problem?

 It seems to work, but volume seems a bit low. I need to get up to around 11 o'clock for a decent volume (I don't listen very loud) with the HD650s. Is this normal? NFB is at it's lowest (for highest impedance phones).

 Thanks for the help!


----------



## balderon

Quote:


  Originally Posted by *xxbaker* /img/forum/go_quote.gif 
_Everyone - I finished putting everything together and noticed that my two 6h6n tubes don't light up. The three other tubes do. I measured heater voltage and it reads: 6.5VAC across the tube pins. That's a little high, could that be causing a problem?_

 

The 6.5VAC heater voltage is within tolerance. There are different heater wiring configurations for V2 depending upon the tube (see this link Bijou Wiring). Did you use pins 4-5 for the heater?


----------



## xxbaker

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_The 6.5VAC heater voltage is within tolerance. There are different heater wiring configurations for V2 depending upon the tube (see this link Bijou Wiring). Did you use pins 4-5 for the heater?_

 

You were totally right! I wired the other way (4, 5 and 9). Now I feel a bit silly for not even thinking about what tubes I was using. Just finished listening to the first 20 minutes of bliss. 
	

	
	
		
		

		
			





 I'll probably post some pics in a few days (or less).


----------



## runeight

Wow, lots of really nice builds have come out lately. Nice work and way better than mine.

 Hope you guys are liking the sound.


----------



## mugdecoffee

So recently my bijou has developed a channel imbalance. The imbalance doesn't follow the tubes when I switched them. I bypassed the pot with no difference. I also redid most of the wiring since it was messy and the heater wire was probably a little too thin. I think that the lower frequencies are more imbalanced than the higher frequencies but I could be wrong. Any ideas for where to start? The only active parts are the tubes and it seems odd that a resistor or cap would change value significantly. This problem did start after I brought the amp back from a meet so it maybe something shifted inside?


----------



## adamus

check the star grounding point (as its mechanical). Check the input circuit first (with the amp off, remembering the otuput caps can still pack a shock (I always discharge them. check the resistance of the pot for each channel. IF that shows nothing...

 Check the voltages, B+, then the anode voltages of the valves. should point to what is going on?

 Also, have you ruled out the source + phones?


----------



## adamus

check the star grounding point (as its mechanical). Check the input circuit first (with the amp off, remembering the otuput caps can still pack a shock (I always discharge them. check the resistance of the pot for each channel. IF that shows nothing...

 Check the voltages, B+, then the anode voltages of the valves. should point to what is going on?

 Also, have you ruled out the source + phones?


----------



## Proutch

Hey guys

 I'm enjoying so much the superb sound of my Bijou, that I thought of using it as a preamp to drive a DYI tripath power amp

 What do you think? Does it make sense?
 Do I need to tweak the Bijou to use it as a preamp?

 Thanks in advance for your help


----------



## chobint

Quote:


  Originally Posted by *Proutch* /img/forum/go_quote.gif 
_Hey guys

 I'm enjoying so much the superb sound of my Bijou, that I thought of using it as a preamp to drive a DYI tripath power amp

 What do you think? Does it make sense?
 Do I need to tweak the Bijou to use it as a preamp?

 Thanks in advance for your help 
	

	
	
		
		

		
		
	


	


_

 

Some have raised concerns about it having too much gain for preamp use, but I think it works just fine. You just need to make sure that the output impedance of the bijou isn't too high for whatever power amp you're using (see runeight's post for specs). I forget what the desirable ratio is off hand. I think those are the main concerns.

 edit: actually, I think most amplifiers have really high input impedance. I'm sure someone will correct me if I'm wrong.

  Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Yep, I have a bunch of those too. And I use them for some holes.

 The Zo of the Bijou is 60R with no NFB (no nfb pot connected).

 With the normal NFB arrangement the Zo is about 20R when the pot is set to its halfway position (125k)._


----------



## xxbaker

Alright so here we go... This is my first time posting pictures on here so let me know if they don't work.

 First one is of me drilling, second is with the boards in and the wiring half done. Last two are of it in operation 
	

	
	
		
		

		
		
	


	




 Of course there's still some more work to do (mount feet, grind down volume knob, track down some stray buzzing, etc.) but it works!


----------



## nattonrice

Crazy clean work there dude! Wonderful.


----------



## MoodySteve

Looking good xxbaker! I *really* hope that that the workpiece in the first picture is securely clamped at the bottom - safety first!


----------



## regal

double post


----------



## regal

Anyone else running the big asco 100uf motor run coupling caps? trying to find a mounting ring that fits them


----------



## luvdunhill

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Anyone else running the big asco 100uf motor run coupling caps? trying to find a mounting ring that fits them_

 

check Allied


----------



## pabbi1

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Anyone else running the big asco 100uf motor run coupling caps? trying to find a mounting ring that fits them_

 

Got mine here - about $10 for 2, which included shipping. Of course, it will take 3 weeks to get them, but, at least they are the right ones.


----------



## mugdecoffee

I've had the resistors for Regals mod for a couple of months and finally got around to switching them out. It was pretty tough to get at them since they're wedged between capacitors and tube sockets so I ended just putting them on the bottom of the board. I'd really recommend doing regal's mod from the start instead of upgrading later. The cost is trivial and the sound improvement is impressive. The imaging is much better when it was already great to start with. I also think that there's a little more impact to the bass now. Overall it seems like the sound cleaned up a little bit. On the other hand I hadn't been listening to my bijou much recently so this is all from memory. There is definitely less noise now and I don't think I changed the wiring that much when reinstalling the boards into the case.

 On the channel imbalance, I think that the problem may be that I also recently recabled the k701s and may have damaged one of the drivers when soldering in the new wires. I think I only notice the difference on the bijou because of the huge soundstage which makes the imbalance seem bigger. It's hard to tell though.


----------



## milosz

I ended up using a Hammond 1441-10BK3 (4 x 2 x 8) steel chassis with matching 1451-10BK3 perforated cover. I used the chassis inverted, like a tray. This allowed me to put the amp in an 8" deep 4" wide 7.25" high enclosure. Some pictures att'd. This is the absolute smallest volume possible for this amp; I needed to stack the amp boards and mount the PS board vertically to get it all to fit in the enclosure.

 I like the look that resulted. Also, the cost of this Hammond enclosure is quite moderate.


----------



## milosz

I thought the Forum would make thumbnails / links of my pictures.....


----------



## funch

A mini Bijou. That is one cool amp. Do you have any hum issues with 
 the tranny right next to the amp boards?


----------



## fishski13

hum and heat? that's quite an impressive chassis job. cute as hell too. nice job milosz!


----------



## milosz

No hum issues.

 Absolute full gain / full feedback - which would be way too loud to actually listen to with a normal line input - you can crank it up to hear hiss and some 60 Hz line hum, but at any gain / feedback setting that you'd actually use for listening it's dead silent.

 The case top and sides are perforated so there is plenty of ventilation, I don't think heat will be any kind of an issue. It does get warm, but then it's tube gear- all tube gear gets warm.

 I just couldn't see putting it in a big old case. There are some nice cases but they cost over $100- these Hammond pices were under $50 as I recall.

 Thanks for the compliment. Usually I'm all thumbs but this turned out OK, maybe in my old age here I am finally learning some patience and how to measure twice and drill once.....


----------



## dean0

Ordering parts for the Bijou Amp, but Iam a little confussed with trafo choice.
 The one listed on Cavalliaudio BOM is the Hammond 270DAX, but I understand this is not compatible with 220v (uk voltage), so what is an alternative?
 Thanks
 dean0


----------



## balderon

Quote:


  Originally Posted by *dean0* /img/forum/go_quote.gif 
_Ordering parts for the Bijou Amp, but Iam a little confussed with trafo choice.
 The one listed on Cavalliaudio BOM is the Hammond 270DAX, but I understand this is not compatible with 220v (uk voltage), so what is an alternative?
 Thanks
 dean0_

 

The 370DAX has the same specs but with 220v primary.


----------



## dean0

thanks just found the page on Cavalliaudio and found this link Tube-Town Online-Store - Hammond 370DAX ha370dax


----------



## funch

You might also look at the 370FX, which has higher current ratings.
 My build has all the tweaks, and I'm using 6H30 input tubes (higher
 heater current), and the 270DAX gets pretty warm. If I had it to do
 over, I would use the FX tranny.


----------



## balderon

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_You might also look at the 370FX, which has higher current ratings.
 My build has all the tweaks, and I'm using 6H30 input tubes (higher
 heater current), and the 270DAX gets pretty warm. If I had it to do
 over, I would use the FX tranny._

 

X2

 dean0: The temperature of my DAX was very warm with a similar setup as funch. With the 90ma 270DAX transfo (w/EZ81/Regal mod) my B+ was dropping to < 238v@96ma. Changing to the 270FX (or 370FX) has worked out very well. The transfo is barely warm and the B+ is at spec with plenty of power to spare and without any significant heat buildup.


----------



## dean0

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_X2

 dean0: The temperature of my DAX was very warm with a similar setup as funch. With the 90ma 270DAX transfo (w/EZ81/Regal mod) my B+ was dropping to < 238v@96ma. Changing to the 270FX (or 370FX) has worked out very well. The transfo is barely warm and the B+ is at spec with plenty of power to spare and without any significant heat buildup._

 

thanks, I was having trouble finding the 370dax in stock anywhere but I can find either 370DX, 370HX and 370FX what is my best option?
 Any other parts need changing to accomidate this transformer?
 Regards
 dean0

 ps Iam building it stock, no mods, to start with anyway...


----------



## balderon

Quote:


  Originally Posted by *dean0* /img/forum/go_quote.gif 
_thanks, I was having trouble finding the 370dax in stock anywhere but I can find either 370DX, 370HX and 370FX what is my best option?
 Any other parts need changing to accomidate this transformer?
 Regards
 dean0

 ps Iam building it stock, no mods, to start with anyway..._

 

No changes are needed. Check out http://www.head-fi.org/forums/5719183-post2595.html


----------



## dean0

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_No changes are needed. Check out http://www.head-fi.org/forums/5719183-post2595.html_

 

Thanks, everything is ordered, appart from enclosure (any suggestions?)
 Little more expensive than I first thought, sure it will be worth it


----------



## balderon

I would recommend applying the Amphead and Regal mods as part of your initial build. It's certainly easier to make a few component changes now rather than later.


----------



## funch

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_X2

 dean0: The temperature of my DAX was very warm with a similar setup as funch. With the 90ma 270DAX transfo (w/EZ81/Regal mod) my B+ was dropping to < 238v@96ma. Changing to the 270FX (or 370FX) has worked out very well. The transfo is barely warm and the B+ is at spec with plenty of power to spare and without any significant heat buildup._

 

I've never had a problem with my B+, but that may be due to the dedicated
 1A heater tranny that I'm using for the EZ81 PS tube.


----------



## adamus

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I would recommend applying the Amphead and Regal mods as part of your initial build. It's certainly easier to make a few component changes now rather than later._

 

agreed on the regal mod, but wont the amphead mod run the tubes out of spec with respect to heater to cathode voltage of the 6922. 

 why not use a the heater CT to reference the voltage? e.g. second diagram







 this would appear to give the positives of ampheads mods, without the negatives?


----------



## adamus

Whilst in the modding mood, could we replace the cathod resistor of the first gain stage with an LED, thus eliminating the bypass resistor? It probably wouldnt work great stock, but with regals mods, the leds should be fairly linear (and have less impact on the signal than the bypass cap?


----------



## fishski13

isn't Amphead's mod just a virtual CT for the heaters, tied to ground - no DC elevation on the cathode biased 6922 as you're suggesting? http://cavalliaudio.com/bijou/main.php?page=heatermods


----------



## adamus

yes, thats precisely what it is, but by doing that you a running the top triode with a difference of 120ish volts between heater and cathode.


----------



## regal

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Whilst in the modding mood, could we replace the cathod resistor of the first gain stage with an LED, thus eliminating the bypass resistor? It probably wouldnt work great stock, but with regals mods, the leds should be fairly linear (and have less impact on the signal than the bypass cap?_

 

I remember looking for a suitable LED to do this and couldn't find one with the right foward voltage to give the correct mA's the PS could handle. If you find one let me know I would love to get rid of those big electrolytic bypass capacitors.


----------



## fishski13

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_yes, thats precisely what it is, but by doing that you a running the top triode with a difference of 120ish volts between heater and cathode._

 

what's the heater to cathode voltage rating? http://www.jj-electronic.com/pdf/E88CC.pdf

 i also don't understand where you are getting 120V. http://cavalliaudio.com/bijou/images...elVoltages.gif 

 btw, my amp is silent with Amphead's mod.


----------



## TimJo

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_what's the heater to cathode voltage rating?_

 

For a 6922

 Heater negative with respect to the cathode - 60 volts max.
 Heater positive with respect to the cathode - 120 volts max.


----------



## adamus

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_what's the heater to cathode voltage rating? http://www.jj-electronic.com/pdf/E88CC.pdf

 i also don't understand where you are getting 120V. http://cavalliaudio.com/bijou/images...elVoltages.gif 

 btw, my amp is silent with Amphead's mod._

 

120v was a guess, i see its 103. 

 Surely ampheads mod puts the heater cathode rating over the edge?


----------



## fishski13

thanks adamus and TimJo. 

 so without Amphead's mod, we have 44V DC elevation with a voltage divider = (65K/65K+348K)x348K. i understand this. this easily gets us under 60V max when the heater goes negative to the cathode.

 i'm no EE, but i thought that the artificial CT negated the need for heater elevation. doesn't the 2 100ohm in parallel to ground create a path of least resistance for any current coupling between the heater and cathode?


----------



## adamus

the potential difference still exists.


----------



## runeight

Sorry gents, been on to other things.

 Amphead's mod puts the heaters at 0VDC. The ECC99s don't care too much because I think they have a max HK voltage of 200V.

 But the 6922 has a max of 130V. With the cathode of the phase splitter at ~100V I opted to reduce this by elevating the heater voltages. It is not absolutely necessary, just an engineering choice. 6922s running with +100V on their cathodes will probably run forever.

 Just be careful, if you make mods, not to stray out of the HK maximum ranges.


----------



## adamus

Alex, excuse my lack of knowledge, but in my head all Ampheads mod does is reduce noise by 'balancing' the 6.3vac (3.15v around 0v). Why not then elevate it with DC to create the safety margin for the HK rating?

 With regard to diode bias, could we not use a red led in series with a small signal diode, thus having around 2.4v grid. Its not that accurate but you could mess with led's. The internal resistance would be around 10ohms, which may still be better than the bypass cap?


----------



## TimJo

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_Why not then elevate it with DC to create the safety margin for the HK rating?_

 

I see no reason why you couldn't do this, but then again I am still a rookie when it comes to tubes. 

 Essentially that's what Alex did in the original design (although only to one side of the heater winding) but it seems for some reason to have induced hum on amphead's build.

 If you have a clean way to tap ~50 vdc from the PS without introducing noise into the cathode, I don't really see any downside. But I'll let Alex chime in to be sure I'm not missing something.


----------



## mugdecoffee

So I fixed my channel imbalance problem. It was the XLR to 3.5mm to TRS adapter chain. I stuck a 4 pin XLR socket in place of the TRS jack on the bijou and the amp came alive again. Regal's mod really transformed the bijou! Everything is much more lifelike. The bass is much improve. Whereas before low notes seemed to drop out, now they're back and with a little more kick. Incredible.

 As an aside, the XLR jack looks awesome, feels awesome plugging cables into, and is much sturdier. Highly recommended even on unbalanced amps.


----------



## balderon

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_<snip> Regal's mod really transformed the bijou! Everything is much more lifelike. The bass is much improve. Whereas before low notes seemed to drop out, now they're back and with a little more kick. Incredible._

 

My ears noticed a dramatic improvement when I replaced the ECC88 with Amperex 6DJ8 Bugle Boy tubes (made in Holland). Unfortunately it's becoming increasingly more difficult to find reasonably priced tubes that are strong and fairly well matched.


----------



## adamus

tried the ruskies? 6n23p-ev are meant to be nice.


----------



## balderon

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_tried the ruskies? 6n23p-ev are meant to be nice._

 

Didn't even know about them before your post! 
	

	
	
		
		

		
			





 Would you say the 6n23p-ev is an improvement over the BB (other than cost, availability, and heater to cathode voltage rating)?


----------



## regal

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_tried the ruskies? 6n23p-ev are meant to be nice._

 

Just a quick glance at the tube curves and the 6n23p-ev would pull way to much current at the stock cathode bias. Doesn't look like a 6DJ8 sub at all. Looks like 7.5 mA with the stock resistors, which is 50% greater than my Regal mod. 

http://www.mif.pg.gda.pl/homepages/f.../6/6N23PEV.pdf


 It could work by increasing the resistances of the cathodes. And maybe the EZ81 would handle the extra 50% mA's but check for the proper voltage drop so you don't burn up the HV reg.



 Edit- I was reading the chart wrong, looks like 3.5 mA draw with the stock resistances.
 If these truley sound as good as BB 6DJ8's it would be a good find, but to try them it would mean reversing the Regal mod. Anyone want to compare these to BB's?


----------



## rolotube

I've been running BB's with regal's mods for some time. This has been my front end setup of choice for the Bijou, having tried some of the other popular tubes (6922, 6N1P, 6H30). But curiosity got the better of me when I read some good reports about the 6N23P, so they had to be tried.

 From the data & comments by other users, it appeared that they were close enough to the 6DJ8 to do a straight swap without changing any other components. My Bijou has been running perfectly with all the above tubes & regal's mods for nearly a year, so I didn't anticipate any problems with the 6N23P's, & this has proved to be the case. They to work fine as a direct substitute for the 6922 & 6DJ8. All critical voltages measure the same as the 6DJ8's (ie. they are the same or close to circuit diagram values) & no components in either amp or PS are running warmer than with the other tubes. Maybe I'm missing something important here (regal, why would your mods need to be reversed??) here but indications are they are running within their limits & by the resulting sound, at a fairly sweet operating point.

 And the sound? Excellent. Different from the BB's, but not by a lot, & every bit as engaging. Perhaps not quite as expansive or holographic as the BB's, but very close. The magical projection of voices & solo instruments is still there, as is the broad soundstage, tight focus & liquid smooth mids. Tops are superb & seem smoother with a tad less grain. I put this down mainly to a lower noise floor than the BB's, which are now getting on for 50 years old & possibly not as quiet as they may have been when newer. Bottom end is extended & full & maybe a bit tighter than the BB's.

 IMO, the 6N23P is up there with the BB as the equal best front end tube I've tried. At about 25% of the price of BB or Orange Globe 6DJ8's they are a bargain.


----------



## regal

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_I've been running BB's with regal's mods for some time. This has been my front end setup of choice for the Bijou, having tried some of the other popular tubes (6922, 6N1P, 6H30). But curiosity got the better of me when I read some good reports about the 6N23P, so they had to be tried.
 Maybe I'm missing something important here (regal, why would your mods need to be reversed??) here but indications are they are running within their limits & by the resulting sound, at a fairly sweet operating point.

 ._

 



 The chart isn't very good but it looks like the tubes will pull an extra 5 mA's of current which could have potentially affected the powersupply. But it sounds like the rectifier and regulator are holding up fine, you may want to check that you have 280V before Q2 and 250V after. Its possible that the 6N23P's would pull down the voltage after the rectifier affecting regulation. Probably not but would be worth a check.


----------



## rolotube

regal, thanks for the advice.

 I'm running an upgraded PS which seems to be coping fine with the extra load of the 6N23P's. This consists of 370DAX, EZ81, Hammond 158L choke, Tubecaps throughout (no electros) & amphead's heater mods. Voltages are: C6 (47uF)/input to choke = 330V; choke output/input to R7 = 302V; output of R7/input to Q2 = 286V; output of Q2 = 250V. All pretty much within spec I think. There's plenty of adjustment available both ways (above & below 250V) with P1. Q2 & R7 run warm but not hot. Q1 & transformer barely get above ambient temp.

 I'd be interested in your comments if you decide to try the 6N23P's.


----------



## nattonrice

Quote:


 Tubecaps throughout (no electros) 
 

AHA! I new I remembered someone that did that.
 I am planning on doing the cap multiplier mod so it is easy to do all film on that side of the sand.
 But what did you do C1 and C3?


----------



## rolotube

C1 = 200Uf 550V Tubecap. The choke & Tubecaps before the regulator may reduce ripple a bit compared to the stock circuit (??), so I figured some compromise in the value of the output cap could be tolerated, particularly given the benefits of using large film caps instead of electros. I'm no expert on this so feel free to correct if I'm talking crap here. Mundorf do a 330uF HV MKP which may be better in this position but its twice the price of the 200uF Tubecap & poses some mounting challenges. Knowing now how good the Bijou can be, & that differences between electro & film caps can actually be detected, I wouldn't hesitate to spend the extra & get the 330uF if I was building again from scratch.

 C2 = 1uF 400V Auricap. Overkill perhaps (some may say a waste of a good signal cap!) but it was on hand.

 C3 = 1000uF 16V Blackgate FK. Sorry, I wasn't correct in saying no electros, but these are about as good as they get. NP's (Blackgate N or Nichicon ES) could probably also be used here if desired, but again, its probably overkill.

 C4,5,6 = 47uF 600V Tubecaps. HV MKP's could likely also be used here to good effect.

 The cap multiplier looks to be the way forward especially if you want to tweak the current in V1A &/or roll in some different tubes. I'd go this way if I was building from scratch again but I'm getting great results with what I've done so far & don't feel the need to change at present.


----------



## nattonrice

Thanks~
 I thought it would have been the 200uf tube cap. I remembered seeing pics of you psu but couldn't find them.

 Hehe the 330uf mkp are my output caps =]


----------



## mugdecoffee

Here's an idea to get rid of the output caps. I may be off but I think the idea is at least theoretically correct even if it won't work in reality. So the output from the tubes has a high DC offset we need to get rid of. Simply using a resistor divider voltage source as the headphone negative/virtual ground would kind of work except tubes vary too much and the offset would change. These variations also make it so that even if we had a self adjusting voltage source for the left tube, the right side's signal might be sitting at a different potential so there's offset between the two channels.

 I propose having two buffered virtual grounds, one per channel for balanced headphones. Schematic:





 The way I think this should work is that the the cap will charge through the resistor until the cap is charged to the DC level of the output signal. The resistor and cap then form a high pass filter that leaves the cap charged. The buffer then provides the virtual ground for the headphones. If each channel had one virtual ground circuit, there should be no DC offset under any circumstances. Essentially, this is taking the output cap and isolating it with a buffer so the cap's sound doesn't come into play.

 Would it work? Not worth it? Would the cap's coloring still make its way through?


----------



## adamus

the trouble with the idea is, if anything fails you will likely put many volts through your beloved headphones.


----------



## mugdecoffee

True. You could add one of AMB's e12 boards as a failsafe. After poking around, I think this is a capacitor multiplier done with an opamp. Even if the cap's sound still made it through the buffer, this circuit would allow the use of much smaller and higher quality film caps. With the cost of large film caps or high quality bypass caps being rather high, this somewhat complex solution might be justified. It could be made as an addon board so you wouldn't have to mess with the original boards besides shorting the output caps.


----------



## nattonrice

Shhhhhhhh! Your ruining my idea of honking huge output caps


----------



## MoodySteve

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_True. You could add one of AMB's e12 boards as a failsafe. After poking around, I think this is a capacitor multiplier done with an opamp. Even if the cap's sound still made it through the buffer, this circuit would allow the use of much smaller and higher quality film caps. With the cost of large film caps or high quality bypass caps being rather high, this somewhat complex solution might be justified. It could be made as an addon board so you wouldn't have to mess with the original boards besides shorting the output caps._

 

I'm not sure the ε12 is usable with the Bijou - what would you power it with and still retain the DC protection?


----------



## runeight

Interesting idea, but ... the e12 is probably not fast enough for certain failures that are rare, but could occur. Also, you'll need to think about the reference for the e12. It is normally referenced to ground or a virtual ground. If you use your virtual ground the e12 will be floating at 125V along with its power supply. Certainly doable, but extra work.

 Is the output of the opamp going to be at 125V? Is it a high voltage opamp? If not, where do its rails come from? Etc. Just asking because, like so many things, I don't understand yet.


----------



## Ant1Xr1st

Some idea about OCL (output capacitor less) Bijow. (See pic.)
 In microcap works fine. 
	

	
	
		
		

		
			





 Any comments?



_[size=xx-small]*sorry 4 my english[/size]_


----------



## amphead

Interesting, maybe Runeight can evaluate your circuit. Cheers


----------



## adamus

I regal modded my bijou last night. 

 its made quite an impact, the mids have got bigger and bass has more authority, it seems to have sped things up a little. this is with the 6dj8. With the 6n1p i dont hear much difference. 

 Bijou + regal mod + bugle boy + 6n6p is a very good amp. 

 my PS with the Rcore transformer didtn bat an eyelid, 250v solid. 

 has anyone used boutiques as the coupling caps (c3 and c4). My brain says... why bother, the signal is then going through a big electrolytic (bypass with a nice cap). 

 anyone notice a significant improvement?


----------



## regal

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I regal modded my bijou last night. 

 its made quite an impact, the mids have got bigger and bass has more authority, it seems to have sped things up a little. this is with the 6dj8. With the 6n1p i dont hear much difference. 

 Bijou + regal mod + bugle boy + 6n6p is a very good amp. 

 my PS with the Rcore transformer didtn bat an eyelid, 250v solid. 

 has anyone used boutiques as the coupling caps (c3 and c4). My brain says... why bother, the signal is then going through a big electrolytic (bypass with a nice cap). 

 anyone notice a significant improvement?_

 



 Thanks, which do you prefer the mod+BB's or the 6n1p's ?


----------



## adamus

bb's by a country mile.


----------



## fishski13

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_bb's by a country mile._

 

i need to try these. sorry, i'm too lazy to search, where's best place to buy?


----------



## adamus

no idea, a mate gave me my pair as payment for some work on an amp.


----------



## cyteen

Has anyone got suggestions as to values to optimize the circuit for 6n1p.


----------



## adamus

its on the cavalli audio website.


----------



## rolotube

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i need to try these. sorry, i'm too lazy to search, where's best place to buy?_

 

BB's are readily available but be prepared to pay - the genuine article isn't cheap. There are reports of inferior copies being peddled by some tube dealers so it might be wise to stick with reputable firms. I got mine from pcX. They periodically have discounts & currently have 20% off which softens the blow a bit. The 6N23P may also be worth considering. There's been some recent discussion of this tube in these pages. IMO, its close to the BB in sound quality for 25-30% of the cost.


----------



## rolotube

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I regal modded my bijou last night. 

 its made quite an impact, the mids have got bigger and bass has more authority, it seems to have sped things up a little. this is with the 6dj8. With the 6n1p i dont hear much difference. 

 Bijou + regal mod + bugle boy + 6n6p is a very good amp. 

 my PS with the Rcore transformer didtn bat an eyelid, 250v solid. 

 has anyone used boutiques as the coupling caps (c3 and c4). My brain says... why bother, the signal is then going through a big electrolytic (bypass with a nice cap). 

 anyone notice a significant improvement?_

 

I'm running the same configuration in my Bijou with the same results. Its an excellent combination.

 C3&4 - I'm using M-Cap Silver/Oil with significant sound improvement over stock MKP's, but any quality film cap should do a similar job. Which one will depend to some extent on what "type" of sound you're after. C3&4 replacement has been discussed a fair bit in these pages. C5 can also be replaced with a film cap for another worthwhile improvement. Bypass is then not necessarily needed; one less cap in the signal path should be better.


----------



## runeight

Quote:


  Originally Posted by *Ant1Xr1st* /img/forum/go_quote.gif 
_Some idea about OCL (output capacitor less) Bijow. (See pic.)
 In microcap works fine. 
	

	
	
		
		

		
		
	


	




 Any comments?



[size=xx-small]*sorry 4 my english[/size]_

 

This circuit might actually work. I'd like to hear how you do. I've been working on something similar for the Bijou II. But different.

 A few things that you probably already know: 
	

	
	
		
		

		
		
	


	




 1. The e12 will not be fast enough if you get any kind of HV arcing in the O/P section.

 2. The regulators will not regulate that well under the heavy current draws that the Bijou might make compared to an active regulator. This is not at all terrible, just something to know.


----------



## viction

I have finished stuffing my boards and am now wiring everthing up. I found a diagram on audiologica for wiring the volume potentiometer but can't find anything for the NFB. The diagram on Cavalli's website is a little vague. TIA.


----------



## Ant1Xr1st

*runeight*, The 'speed' of e12 low because of a relay. it can disconnect the load only for 20ms. I have 2 ideas - try to use a reed switch (its 10 times faster then the relay), or try the mosfet switch...


----------



## balderon

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i need to try these. sorry, i'm too lazy to search, where's best place to buy?_

 

I picked up a strong pair of BB's on E-Bay and have been very pleased with the sound! Apparently there are many fakes out there and I would suggest reading Joe's Tube Lore - 6DJ8 specifically the section labeled "Danger Will Robinson!".

 Has anyone compared the US Amperex 6922, PQ, white label and the BB's?


----------



## balderon

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_has anyone used boutiques as the coupling caps (c3 and c4). My brain says... why bother, the signal is then going through a big electrolytic (bypass with a nice cap). 

 anyone notice a significant improvement?_

 

I replaced C3/C4 with Auricaps but I don't know if anyone would classify these as boutiques. Although my ears did not hear a huge difference in the sound. IMO I would say more warm, rich sounding, mid range.


----------



## runeight

Quote:


  Originally Posted by *Ant1Xr1st* /img/forum/go_quote.gif 
_*runeight*, The 'speed' of e12 low because of a relay. it can disconnect the load only for 20ms. I have 2 ideas - try to use a reed switch (its 10 times faster then the relay), or try the mosfet switch..._

 

ant1xr1st, the e12 is slow (for what we're talking about) for two reasons. One reason is the relay the other is its built-in time constant. This time-constant is set so that the e12 does not respond quickly to short duration DC excursions. I know that you already know this.

 So, a faster relay definitely helps but the e12 will always take 20ms or more to engage because of its integration time.

 It is true, also, that we are discussing potential problems that would be very, very rare, such as a plate to cathode arc or something similar that would bring either of the rails to the output very fast. If this kind of thing never happens then the e12 will be sufficient for anything else that I can think of. But anything that shorts the output to either rail will blow the headphones before the e12 will engage.

 Which doesn't mean you shouldn't try the idea. It just means that you may run this amp for 100 years and never have a problem. Or you may run it for two days and blow your headphones. But, it's still a good idea.


----------



## Ant1Xr1st

*runeight*, you are right) But now i have much simple idea - just add two tvr-diode (inline, opposite to each other) to the output


----------



## runeight

Yes, that should work.


----------



## dean0

Iam populating the boards, but I have a simple question for you guys. 
 What is the orientation of the LED's on the Amp boards? 
 There seems to be no indication on the silkscreen. 
 Regards
 Dean


----------



## milosz

I built a Bijou, and love it. I know very little about the Little Dot MK III (or it's tube-rolled, better-parts version the MK IV) - how does the Little Dot Mk III compare to the Bijou?


----------



## cfcubed

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_Has anyone compared the US Amperex 6922, PQ, white label and the BB's?_

 

I did but not in this amp, in the CTH. Played quite a bit w/cans in my sig & prefer my 6922 PQ over my 6dj8 BB. Perhaps because PQ was NOS & BB used (but tested very good). BTW as has been said here - BBs on the bay could be long in the tooth.


----------



## regal

IMO a good pair of BB's beats the 6922 PQ's in this amp. The 6922 aren't as smooth probably because they like more current than 6DJ8's.


----------



## dean0

Need some confirmation before I wire up the trafo. Im using the Hammond 370FX. 
 For UK voltage, what should I use on primary 220vac or 240vac, does it matter?

 For 240vac;

 -Connect Brown to Black
 -Blue (Active)
 -White (Neutral)

 Look okay?
 Info from here;
Hammond Mfg. - Universal Primary - "Classic" Power Transformers

 ps Can the Chassis Earth from the IEC connector be connected to the star Ground?

 Thanks


----------



## dean0

anyone?


----------



## runeight

Do you know what your mains voltage is? If you do I would try setting the primary for that first to see what you get.


----------



## dean0

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Do you know what your mains voltage is? If you do I would try setting the primary for that first to see what you get._

 

yes, uk voltage varies from 220v-240v, so what would be best?


----------



## runeight

Try the 240V wiring first. See if you can dial up the B+ to 250V when powering the amps. If you can't then wire for 220V. Let us know how you do.


----------



## adamus

my voltage sits over 240. Highest i have seen it is 249. 220 will mean higher heater voltage, higher B+. Try it on 240 and see how you get on. Its only a couple of solder joins if its wrong.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_my voltage sits over 240. Highest i have seen it is 249. 220 will mean higher heater voltage, higher B+. Try it on 240 and see how you get on. Its only a couple of solder joins if its wrong._

 

Thanks


----------



## dean0

Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Try the 240V wiring first. See if you can dial up the B+ to 250V when powering the amps. If you can't then wire for 220V. Let us know how you do. 
	

	
	
		
		

		
			



_

 

thanks, will do, progress pic's tommorow


----------



## fishski13

Quote:


  Originally Posted by *dean0* /img/forum/go_quote.gif 
_thanks, will do, progress pic's tommorow_


----------



## Ant1Xr1st

Some update of my recent post about the dc-coupled bijou.


----------



## dean0

My build is coming along nicely, just waiting for front/top panels to be done and then I will wire it all up. 
 Can someone double check my wiring so far, I have the primary configured for 240VAC input Hammond 370FX trafo (Hammond Mfg. - Universal Primary - "Classic" Power Transformers)

 Primaries; (240VAC)
 BROWN / BLACK - Tied together
 BLUE - Live
 White - Neutral

 Thanks


----------



## adamus

looks good to me. 

 is you nfb pot linear or log. The bom specifies linear. I log will work, but will have all the adjustment at one end.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_looks good to me. 

 is you nfb pot linear or log. The bom specifies linear. I log will work, but will have all the adjustment at one end._

 

Yes it is log pot. (Alps RK27 250k), thanks must have missed that when ordering parts, ow well... 
	

	
	
		
		

		
		
	


	




 My panels should be here by friday, from frontpanelexpress, then I will take more pics when it arrives.

 edit, Is it okay to power up the p/s without the amp boards attatched, just to make sure im getting 250v out the end


----------



## adamus

from the cavalli audio website

 The Power Supply

 1. Connect the power supply board to the transformer. Double check the wiring to make sure that the HV and Heater secondaries are attached to the correct terminals on the board.
 2. Connect the board to the star ground point.
 3. Connect the ground for the line (mains) to the star ground point.
 4. Be sure that you are powering the transformer through an appropriate power switch and fuse.
 5. Attach a 100k/1W resistor to the 250V and Gnd output terminals.
 6. Double check everything.
 7. Attach a DVM set to at least 300VDC across the 100k test resistor.
 8. Power up the PS module. The EZ80 should light up. If it does not, turn the power off immediately and recheck the transformer connections.
 9. If the EZ80 lights ok check the voltage shown on the DVM. Adjust the trimpot, P1, until the output reads 250V.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_from the cavalli audio website

 The Power Supply

 1. Connect the power supply board to the transformer. Double check the wiring to make sure that the HV and Heater secondaries are attached to the correct terminals on the board.
 2. Connect the board to the star ground point.
 3. Connect the ground for the line (mains) to the star ground point.
 4. Be sure that you are powering the transformer through an appropriate power switch and fuse.
 5. Attach a 100k/1W resistor to the 250V and Gnd output terminals.
 6. Double check everything.
 7. Attach a DVM set to at least 300VDC across the 100k test resistor.
 8. Power up the PS module. The EZ80 should light up. If it does not, turn the power off immediately and recheck the transformer connections.
 9. If the EZ80 lights ok check the voltage shown on the DVM. Adjust the trimpot, P1, until the output reads 250V._

 

Thanks, for point 5. Does that mean one end of the res. in 250v output pin, and the other end on the DMM, same for ground output? (just for testing)
 Thanks again


----------



## adamus

one end of the resistor in the 250v point, the other end to the ground point (on the PS board). Then measure the voltage across the resistor CAREFULLY! if you slip and short then the mosfet will be toast.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_one end of the resistor in the 250v point, the other end to the ground point (on the PS board). Then measure the voltage across the resistor CAREFULLY! if you slip and short then the mosfet will be toast._

 

lol, okay, thanks for making that clear


----------



## fishski13

looks great dean0!

 make sure you drain the caps when finished testing.


----------



## adamus

yes, the output caps (the big upside down ones on the amp boards) maintain considerable voltage when off. Clip a crocodile lead in two, and solder a 100k 1watt resistor between the two ends. Then you will use that lead over and over again with tube gear (make sure you heatsshrink it). clip the lead to each cap leg and wait a few minutes to drain the cap. I always then test the volatge to check it worked


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_yes, the output caps (the big upside down ones on the amp boards) maintain considerable voltage when off. Clip a crocodile lead in two, and solder a 100k 1watt resistor between the two ends. Then you will use that lead over and over again with tube gear (make sure you heatsshrink it). clip the lead to each cap leg and wait a few minutes to drain the cap. I always then test the volatge to check it worked_

 

Ordered 100k 1watt res. should be here tommorow , what fuse would you reccomend 3A or 6A? 
 thanks


----------



## adamus

both seem too big to me. 1amp slow blow should be ok on 240v, maybe 1.5amp.


----------



## dean0

Power supply tested, left on for a couple of hours no problems, had to adjust the voltage 3 times to keep it at 250v. Still waiting on panels before I go ahead and hook the rest up, more pic's later this week, I hope...


----------



## GWorlDofSPACE

Hi guys,

 I am building this wonderful amp and was wondering if I could add bigger polypropylene caps as 1uF for C6 and on PSU C2? I am doing it whit regals tweak and for K-701 headphones whit NFB.
 Please help!

 Thanks.


----------



## GWorlDofSPACE

)


----------



## runeight

Yes, you can add the bigger caps just so long as they are rated for 250V.


----------



## GWorlDofSPACE

What size of cap? Has anyone experimented whit that? How about to remove the output electrolytic caps and replace whit polypropylene or oil?


----------



## ntrl

Another Bijou born.

 Transformer custom ordered (In 220V, Out: 260V .15A x2 and 6.3V 3.5A).
 Temporary Case is ikea's foodsaver. 
 Jeff's kit. 






























 Ventilation holes





 Ventilation holes





 Temp of near tube





 Temp of 6Н6П (6N6P)





 Case temp





 Heater

 Thanks to authors of Bijou, Jeff and head-fi community. 
	

	
	
		
		

		
		
	


	









 PS. Where in Ebay buy good chassis for bijou < 40$ ?


----------



## adamus

basic but functional - but maybe a bit of a fire risk?

 The last pic - not sure i would have so much exposed wire. it wouldnt take a lot to short them.


----------



## _Snoopy_

Has anybody tried leaving out C1? Should be o.k.for high-z headphones.


----------



## dean0

Finished my build but I have hum/buzz problem. With nothing connected, I can turn volume 20% with no noise then I get hum/buzz. If I touch starground and my volume knob the hum does decrease a little, also tried moving some wires with no success. When my DAC is connected the hum/buzz is worse, but music 
 plays fine.
 Iam not using the NFB atm, and remove R12, and replaced R1 with 300ohm.
 Voltages both measure a constant 250v on both boards. 
 Iam thinking that connecting starground to volume pot, and Amphead's Heater Mods may help, any ideas or input would be much appreciated.


----------



## dean0

okay, I seem to have solved one issue of noise when the DAC is not connected, running a peice of wire from the starground to the chassis got rid of noise, only on full volume their is a slight hum, bearly audioble.
 But when the DAC is connected Iam still getting noise, alot less than before but it is there. 
 Iam using Gamma y2 DAC powered by usb and feed via Optical from my soundcard.
 When I unplug the usb power source the noise goes, does that mean using a different 5v external powersupply would eliminate the problem?
 Is their any negetive effects on SQ using Amphead's Heater Mods, I may do this mod to see what kind of effects it has.


----------



## adamus

have you grounded the IEC to the chassis (not the star ground?)


----------



## ntrl

My first impressions.

 In 2006 i have Senn HD580 and build AMB M3. I was happy.
 I could listen to music 4-5 hours. without any inconvenience to the ears and head. In 2009 I bought the AKG K701. AKG course much detail. But more than 2 hours I could not listen to music. began some inconvenience.

 Now with BIJOU and AKG k701 I can safely listen music 4-5 hours. 
	

	
	
		
		

		
		
	


	




 PS. M3 with BB OPA627, source EMU 1212m.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_have you grounded the IEC to the chassis (not the star ground?)_

 

I have grounded the iec to starground. The starground is isolated from the chassis.


----------



## mugdecoffee

Quote:


  Originally Posted by *dean0* /img/forum/go_quote.gif 
_okay, I seem to have solved one issue of noise when the DAC is not connected, running a peice of wire from the starground to the chassis got rid of noise, only on full volume their is a slight hum, bearly audioble.
 But when the DAC is connected Iam still getting noise, alot less than before but it is there. 
 Iam using Gamma y2 DAC powered by usb and feed via Optical from my soundcard.
 When I unplug the usb power source the noise goes, does that mean using a different 5v external powersupply would eliminate the problem?
 Is their any negetive effects on SQ using Amphead's Heater Mods, I may do this mod to see what kind of effects it has._

 

I use an Opus DAC with my Bijou and with USB input I got lots of buzzing too which I realized stopped when I ran my laptop off of its battery. I ended up getting a plug adapter that disconnected the ground pin of my laptop charger (it connects with 2 pins now instead of three) and that fixed it. There's probably a better way (maybe a ground loop breaker?) but that worked for me.


----------



## dean0

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_I use an Opus DAC with my Bijou and with USB input I got lots of buzzing too which I realized stopped when I ran my laptop off of its battery. I ended up getting a plug adapter that disconnected the ground pin of my laptop charger (it connects with 2 pins now instead of three) and that fixed it. There's probably a better way (maybe a ground loop breaker?) but that worked for me._

 

thanks for the advice, sounds like the same issue


----------



## dean0

I have grounded the iec to starground. The starground is isolated from the chassis. Could this be causing, hum issues?


----------



## adamus

you should always have the iec ground connected directly to the chassis, with a star washer (to bite into the chassis). Its for safety and may even help the hum (it can also cause it on occasions).


----------



## dean0

will do thanks, for Amphead's Heater Mod do I put some 100ohm 1/2W res. in the 6.3v inputs on the ps board and run them to starground?
 edit; also for measuring volatges on the boards, do I put on end of the DMM on the starground and other on measuring point?
 thanks


----------



## adamus

yes for measuring voltages. 

 ampheads transformer mod - see the cavalli audio site, there is more to it than that. I would prefer to elevate the CT of the heaters too, If i get time i'll have a quick look at the schematic to see how that would be possible. Ampheads mod references the heater to ground. The upper triode will have a heater ctahode voltage that exceeds, or very enarly exceeds the max rating. it would be better to reference the CT to say 40v plus. as it is its not the CT, but one end of the heater supply.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_yes for measuring voltages. 

 ampheads transformer mod - see the cavalli audio site, there is more to it than that. I would prefer to elevate the CT of the heaters too, If i get time i'll have a quick look at the schematic to see how that would be possible. Ampheads mod references the heater to ground. The upper triode will have a heater ctahode voltage that exceeds, or very enarly exceeds the max rating. it would be better to reference the CT to say 40v plus. as it is its not the CT, but one end of the heater supply._

 

Okay thanks, I understood some of what your saying, on the website refering to the mod;






[/url]

 So I remove R9 and C7 and connect the x2 100ohm 1/2W res. from the 6.3v inputs on the powersupply to starground?
 thanks again for your patients and help


----------



## dean0

Is this right for Amphead Mod


----------



## adamus

yes, with the other components removed. Dont do it unless you have issues though. The current design works the tubes in a nice zone.


----------



## adamus

this would potentially a better way (Anyone reading please correct me if i am wrong)

 I am not sure how this would work on the board, or if its possible.


----------



## dean0

I connected the starground to the chassis and also iec, and the the buzz/hum has been almost eradicated, you can bearley hear it only over 50% volume, also my B+ went up from 249v to 254v. I have trimmed it down and is now constant 250v accross all boards. 
 But there is still a very faint hum which I would like to resolve. Moving wiring has no effect, Iam thinking Ampheads mods may be my next option. Does the mod have negetive effects on SQ?
 Thanks


----------



## adamus

as i have said... it puts the top triode near the heater cathode limit. 

 try it, its pretty easy.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_as i have said... it puts the top triode near the heater cathode limit. 

 try it, its pretty easy._

 

would it make more sense then, using the EZ81 instead of EZ80 what Iam currentley using, am I right that it can handle more current?
 thanks


----------



## adamus

nope, if you voltage is fine then thats all you need. If you do the regal mod then you will need and EZ81. you only need an ez81 if you cant regulate to 250v (i.e. you are under it). 

 try the amphead mod, it may eliminate that last bit of hum.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_nope, if you voltage is fine then thats all you need. If you do the regal mod then you will need and EZ81. you only need an ez81 if you cant regulate to 250v (i.e. you are under it). 

 try the amphead mod, it may eliminate that last bit of hum._

 

thanks, Iam going to order the EZ81 and the parts for regal/amphead mod, what are some nice tubes Iam currentley using ECC99/6922


----------



## adamus

ecc99 and amperex bugle boy 6dj8 are nice to my ears.


----------



## dean0

Amphead mod done, powered up fine, and the hum is slightley less, you can bearley hear it only near full volume, hopfully after regal mod/ez81 power supply and some 6DJ8 bugle boy valves it will be completley gone.
 I will update soon


----------



## diego

I think the best way to do Amphead's mod on the Bijou is the way Adamus suggests. That's the way I did it in a different tube amp and it worked great. It centers the heater wires and keeps the cathode elevated by 40v. I think also that the star ground should be connected to the chassis. Finally, you can try to run separate heater wires for each tube the way ntrl did. It decreases the current flowing through the output tube's heaters and may reduce hum a bit. All this taking into account heater wire routing of course.

 If you do Amphead's mod you should keep only one path to ground though, so you should take out R10, R9 and C7 as the website says.


----------



## adamus

When i get time i'll see if its posisble on the boards, the 40v is elevated on the ps board to one leg of the heater, which is also used for the ez81... I'lll have a look at some point.


----------



## trv

Hi, my next project will be Bijou.
 Just basic question to be sure.

 - I live in europe and powergrid is 230V, i will use Hammond 370 DAX transformer. Do I need to make these following "tweaks"?

 * Amplifier - Change R5, R6, R7 to 33.2kΩ.
 * Power Supply - Change R2 to 34.8kΩ.

 I bet this has been covered in this topic but it´s soooooo long.


----------



## dean0

Quote:


  Originally Posted by *trv* /img/forum/go_quote.gif 
_Hi, my next project will be Bijou.
 Just basic question to be sure.

 - I live in europe and powergrid is 230V, i will use Hammond 370 DAX transformer. Do I need to make these following "tweaks"?

 * Amplifier - Change R5, R6, R7 to 33.2kΩ.
 * Power Supply - Change R2 to 34.8kΩ.

 I bet this has been covered in this topic but it´s soooooo long._

 

yes that is right, good luck with the project, it is a wonderful amp.


----------



## trv

Thanks.

 Just finished building valve phono pre-amp, pre-amp and poweramp.
 Now started to build vinylplayer, my version of Linn Sondek (or two) and this Bijou


----------



## GWorlDofSPACE

Quote:


  Originally Posted by *dean0* /img/forum/go_quote.gif 
_yes that is right, good luck with the project, it is a wonderful amp._

 

I am a little confused. I am building one whit regals mode and whit choke. I will use 370DAX, but as I am understanding it for 220V configuration instead of 250V you need this changes, other wise not. Is this correct?


----------



## Ferrari

Those resistor changes in the power supply and amp boards are NOT valid for normal 250V B+.
 It’s only needed if you want to build a PS using Hammond 270AX transformer, which outputs 220V B+.


----------



## dean0

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Those resistor changes in the power supply and amp boards are NOT valid for normal 250V B+.
 It’s only needed if you want to build a PS using Hammond 270AX transformer, which outputs 220V B+._

 

I made those changes to the p/s and amp boards, using 370FX (primaries 240VAC), and Iam running B+ 250v? Is this not correct?


----------



## Ferrari

Where have you read that these changes are necessary for 250V B+ ???

 However, you can get the desired 250V B+ using the 10 KOhm trimpot on the PS, as you have noticed already.


----------



## dean0

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Where have you read that these changes are necessary for 250V B+ ???

 However, you can get the desired 250V B+ using the 10 KOhm trimpot on the PS, as you have noticed already._

 

I misread the info, thinking that the 220v stated was for the operation input voltage, not the B+ Voltage. As I said before Iam running B+ 250v fine, would I gain any benifit changing the parts to their original values?


----------



## mugdecoffee

I got a pair of Grados recently which are much lower impedance than any other headphones I was using in my Bijou before. There is this terrible hum in one channel that doesn't move with the tubes and it goes crazy when I touch the feedback pot and gets pretty loud when I touch the volume knob. Any ideas?

 EDIT: A big part of the hum seems to be coming from my laptop charger which is on the floor a couple of feet away. I think the rest of the hum is probably coming from other devices. Do I need a ground look breaker?


----------



## bhjazz

Hi mug. Welcome! I'd first start by reflowing joints, ground joints in particular, on your volume knob, feedback pot, etc. Also, does the sound move if you move the laptopn charger? If reflowing these does nothing, you might want to post a few photos of your wiring scheme. There may be some wiring path issues we need to troubleshoot. (Forgive me if you've already posted pics. Just jumping in to lend a hand!)


----------



## dean0

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_I got a pair of Grados recently which are much lower impedance than any other headphones I was using in my Bijou before. There is this terrible hum in one channel that doesn't move with the tubes and it goes crazy when I touch the feedback pot and gets pretty loud when I touch the volume knob. Any ideas?

 EDIT: A big part of the hum seems to be coming from my laptop charger which is on the floor a couple of feet away. I think the rest of the hum is probably coming from other devices. Do I need a ground look breaker?_

 

Is your chassis and volume pot connected to the star-ground/chassis? If not connect it. Also your the ground from the IEC socket should be connected to your chassis.
 I had simular problems and doing this solved it. Quick test, get a peice of wire a put one end on your starground and the other on the metail body of the volume pot. 
 Pictures would be helpful, as it could be a wiring issue.
 dean0


----------



## mugdecoffee

So I've had problems with noise that comes from my laptop charger through my laptop to the USB cable to my Opus DAC and my fix was to to get a 3 prong to 2 prong power adapter for my laptop charger. Basically I ungrounded my laptop charger. When I get rid of the adapter and ground the charger the noise disappears but I get the noise through USB again. The only noise free solution is to run my laptop on battery.

 My chassis is connected to the star ground which is connected to the IEC's earth. I got a jumper cable and connected it from the star ground point to everywhere to was supposed to be grounded but the noise continues. I'm pretty sure my wiring isn't at fault but instead a more fundamental grounding problem. I'm pretty sure I'm getting a ground loop between my charger and the bijou PSU though I'm not quite sure what that means.


----------



## dean0

mugdecoffee;6266699 said:
			
		

> So I've had problems with noise that comes from my laptop charger through my laptop to the USB cable to my Opus DAC and my fix was to to get a 3 prong to 2 prong power adapter for my laptop charger. Basically I ungrounded my laptop charger. When I get rid of the adapter and ground the charger the noise disappears but I get the noise through USB again. The only noise free solution is to run my laptop on battery.
> 
> My chassis is connected to the star ground which is connected to the IEC's earth. I got a jumper cable and connected it from the star ground point to everywhere to was supposed to be grounded but the noise continues. I'm pretty sure my wiring isn't at fault but instead a more fundamental grounding problem. I'm pretty sure I'm getting a ground loop between my charger and the bijou PSU though I'm not quite sure what that means.[/QUOT
> 
> Try connecting your DAC via optical, eliminating USB problems.


----------



## fishski13

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_So I've had problems with noise that comes from my laptop charger through my laptop to the USB cable to my Opus DAC and my fix was to to get a 3 prong to 2 prong power adapter for my laptop charger. Basically I ungrounded my laptop charger. When I get rid of the adapter and ground the charger the noise disappears but I get the noise through USB again. The only noise free solution is to run my laptop on battery.

 My chassis is connected to the star ground which is connected to the IEC's earth. I got a jumper cable and connected it from the star ground point to everywhere to was supposed to be grounded but the noise continues. I'm pretty sure my wiring isn't at fault but instead a more fundamental grounding problem. I'm pretty sure I'm getting a ground loop between my charger and the bijou PSU though I'm not quite sure what that means._

 

anybody have a prefered ground-loop breaker?

 where/how are you're inputs grounded? got a pic of your star-ground and wiring?


----------



## trv

Quote:


  Originally Posted by *Ferrari* /img/forum/go_quote.gif 
_Those resistor changes in the power supply and amp boards are NOT valid for normal 250V B+.
 It’s only needed if you want to build a PS using Hammond 270AX transformer, which outputs 220V B+._

 

So no resistor changes are needed if using Hammond 370DAX with 230V powergrid? Have to make sure as i´m starting to do this in hour or two


----------



## Ferrari

Who told you (or where have you read) that these resistor changes are necessary for Europeans 230V AC ???


----------



## trv

check page previous page.

 Obviously i didnt fully understand the 220v operation tweak on cavalli page, so i asked here and got a reply that those are needed.

 No harm done, didnt start yet. Just bought some extra resistors that i can use in other projects.


----------



## mugdecoffee

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_anybody have a prefered ground-loop breaker?

 where/how are you're inputs grounded? got a pic of your star-ground and wiring?_

 

Success with the ground breaker! I used a 10R 10W resistor from Radioshack paralleled with a .1uf WIMA cap (which is rated for 400V and should be good? not sure if its class X or Y) as per AMB's site. The USB noise is very quite and mostly covered by a low 60hz hum I need to track down next. I'd like to try the diode breaker I saw Dr. Gilmore recommended over the resistor/capacitor one I used but he recommends 5A diodes which I don't have. The diode version I think basically floats the ground up to .7V difference which should work better than soft grounding through a resistor.

 I'm really too embarrassed of my wiring to post pictures 
	

	
	
		
		

		
		
	


	




 One of these days I'll get around to recasing the thing and putting in tolerable wiring while I'm at it.

 dean0: I don't have an optical input yet, just USB. I can see now though that optical has some good advantages. I think SPDIF pulse transformers would also eliminate this grounding problem.


----------



## balderon

This is good news mugdecoffee! I am also trying to resolve a *very subtle* 60hz hum I hear in both ears but slightly more pronounced in the left channel. 
	

	
	
		
		

		
		
	


	




 It can only be heard when no input signal is playing or when the input is disconnected regardless of the volume / feedback levels. The faint hum seems to phase in and out. My wife's golden ears heard the hum and she mentioned I am being too critical because it is so faint.

 I have added both the Regal and Amphead mods. Also I have added a RC network safety ground between chassis and signal grounds. Swapping tubes including the EZ81 has had no effect. The hum is likely related to the heater wiring. When the amp powered and warmed up the hum will disappear once I disconnect the heaters at the transfo. Moving the heater wiring has had no effect. I tried to keep all AC and DC circuits separated as much as possible by routing all AC wiring on the opposite side of my chassis than the DC. One sure fix would be to update to DC heaters but my free space in the chassis is limited and not sure if I could fit in a different transfo.

 Anyone have any ideas?


----------



## mugdecoffee

Regulated DC filament supply

 This DC filament supply looks like it would work well since you can use the 6.3AC heater winding on the transformer you already have. I didn't see any PCBs under his ebay listings though. It looks simple enough to breadboard and the choke could probably be omitted.


----------



## fishski13

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_Success with the ground breaker! I used a 10R 10W resistor from Radioshack paralleled with a .1uf WIMA cap (which is rated for 400V and should be good? not sure if its class X or Y) as per AMB's site. The USB noise is very quite and mostly covered by a low 60hz hum I need to track down next. I'd like to try the diode breaker I saw Dr. Gilmore recommended over the resistor/capacitor one I used but he recommends 5A diodes which I don't have. The diode version I think basically floats the ground up to .7V difference which should work better than soft grounding through a resistor.

 I'm really too embarrassed of my wiring to post pictures 
	

	
	
		
		

		
		
	


	




 One of these days I'll get around to recasing the thing and putting in tolerable wiring while I'm at it.

 dean0: I don't have an optical input yet, just USB. I can see now though that optical has some good advantages. I think SPDIF pulse transformers would also eliminate this grounding problem._

 

good to hear. the Bijou is a special amp and well worth the effort.

 re: USB noise - are you hearing noise during quiet music passages? if not, is the input left floating when no music is playing, i.e. are you picking up simple RFI? PS/rectifier/TX placement could be causing the noise as well. also, not all wiring is equal, and a properly grounded/enclosed aluminum chassis will be of benefit. 

 re: 60Hz ground noise - i'm interested if the diodes fix this. should be easy/cheap to try. 

 here's a couple of simple DC heater schematics. i've used the top one with good results to power a bunch of LEDs, in addition to heaters, in a guitar amp where the LEDs were in close proximity to signal runs: diyAudio. the attached pic is my P2P effort.


----------



## CountChoculaBot

I'm having to replace a pair of ECC99's since one of them is distorting bass like crazy, so I'm here for advice on what route to go.

 I could either get one JJ ECC99 for ~$20, or I could get a set of JJ ECC99 Gold Pins for ~$60 (any idea where to get this matched?). I'm not sure if there's a point to the latter, since none of the other tubes in the amp are gold pins.

 Oh and ah... without having to sort through 205 pages, JJ ECC99's are generally going to be my best bet for tubes right? Or can anyone direct me to impressions of various tubes with this amp? I prefer a tubey, smooth and sweet sound, don't really care about detail/soundstage/bass if I had to sacrifice them, though I don't mind them.


----------



## balderon

My ears favor the Amperex 6dj8 bugle boy + JJ ecc99 + regal mod. I have tried the 6n6p's driving my HD-650 and IMO the sound was dull and uninspiring.


----------



## funch

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_Regulated DC filament supply

 This DC filament supply looks like it would work well since you can use the 6.3AC heater winding on the transformer you already have. I didn't see any PCBs under his ebay listings though. It looks simple enough to breadboard and the choke could probably be omitted._

 

This is the circuit I used on my EHHA, and it worked so well that I'm going
 to put one together for my Bijou. The EHHA with 6H30's was unlistenable
 with AC heaters, but dead quiet with this DC heater circuit. I also have
 a very slight hum in one channel of my Bijou, so I'll report back once the 
 parts arrive and I install it. BTW, I had to change the regulator to an
 LD1084V, rated at 5 amps.

 I'm using 6H30's in, and ECC99's out, and the current draw of those four
 tubes pretty well max'es out the 3.5A heater current of the 270DAX, which
 probably explains why my tranny runs hot. I have a separate 1A heater 
 tranny for the EZ81, otherwise I couldn't run the 6H30's.


----------



## milosz

Hey REGAL-

 Looking at the Cavalli Audio site, under TWEAKS it says, "Regal's mods requires using ECC99s (not 6N6Ps) and the EZ81 Power Supply." 

 I thought I read someplace that you are using 6N6Pi not ECC99? Do you have a preference in terms of sound? Or maybe it seems maybe the 6N6Pi might consume a little more current, which it seems would then tax the power supply making insufficient current avaialble for the higher-bias setup of the 6DJ8....?


----------



## regal

We found that in most cases the power supply had enough current to support 6n6p's.


----------



## pabbi1

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_This is the circuit I used on my EHHA, and it worked so well that I'm going to put one together for my Bijou. The EHHA with 6H30's was unlistenable with AC heaters, but dead quiet with this DC heater circuit. I also have a very slight hum in one channel of my Bijou, so I'll report back once the parts arrive and I install it. BTW, I had to change the regulator to an
 LD1084V, rated at 5 amps.

 I'm using 6H30's in, and ECC99's out, and the current draw of those four tubes pretty well max'es out the 3.5A heater current of the 270DAX, which probably explains why my tranny runs hot. I have a separate 1A heater tranny for the EZ81, otherwise I couldn't run the 6H30's._

 

Any plans to do a board run with the mods? I was looking at those heaters for another project, but couldn't source some of the parts. While I have 6n6p/6n1p currently, I also have a stash of 6h30 and 6n23.

 And I said I'd never mod the working balanced Bijou - who am I kidding?


----------



## gabriel-dan

Quote:


  Originally Posted by *dean0* /img/forum/go_quote.gif 
_Finished my build but I have hum/buzz problem. With nothing connected, I can turn volume 20% with no noise then I get hum/buzz. If I touch starground and my volume knob the hum does decrease a little, also tried moving some wires with no success. When my DAC is connected the hum/buzz is worse, but music 
 plays fine.
 Iam not using the NFB atm, and remove R12, and replaced R1 with 300ohm.
 Voltages both measure a constant 250v on both boards. 
 Iam thinking that connecting starground to volume pot, and Amphead's Heater Mods may help, any ideas or input would be much appreciated.












_

 

Hi Dean0
 Nice job. What casing did you use? nice face plate. Did you use standoff/spacers to raise the PCB?


----------



## funch

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Any plans to do a board run with the mods? I was looking at those heaters for another project, but couldn't source some of the parts. While I have 6n6p/6n1p currently, I also have a stash of 6h30 and 6n23.

 And I said I'd never mod the working balanced Bijou - who am I kidding? 
	

	
	
		
		

		
		
	


	


_

 

I wouldn't know how to design a circuit board to save my keester.
 This is the proto-board I used in my EHHA: Multipurpose PC Board with 417 Holes - RadioShack.com.
 You can see it in post #6148 in the 'Builds' thread. I didn't use the
 choke, though. I didn't seem to need it. The parts came from Digikey.
 The parts for the one for the Bijou are coming from Mouser.


----------



## trv

Hi Deano, stunning chasis! 

 What is that headphone plug?
 Name and model, I want to have buy same kind.
 Where can i order one?


----------



## balderon

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_This is the circuit I used on my EHHA, and it worked so well that I'm going
 to put one together for my Bijou. The EHHA with 6H30's was unlistenable
 with AC heaters, but dead quiet with this DC heater circuit. I also have
 a very slight hum in one channel of my Bijou, so I'll report back once the 
 parts arrive and I install it. BTW, I had to change the regulator to an
 LD1084V, rated at 5 amps.

 I'm using 6H30's in, and ECC99's out, and the current draw of those four
 tubes pretty well max'es out the 3.5A heater current of the 270DAX, which
 probably explains why my tranny runs hot. I have a separate 1A heater 
 tranny for the EZ81, otherwise I couldn't run the 6H30's._

 

I looked at Regulated DC filament supply circuit and I don't understand how it would work for the Bijou. (I expect powering the EZ81 heater using 6.3vac and use the DC circuit to power the amp tubes) Best case each Schottky doide will drop ~0.5v each so for each cycle I would expect a drop of at least 1 volt. The total filtered voltage would be ~5.3v or less going to the regulator (already low for the heaters). I didn't look at the specs for the regulator but lets say the regulator is an LDO and the dropout voltage is ~0.5v so the most you could deliver to each heater (regulated) would be ~4.8v which seems quite low. What am I missing?


----------



## balderon

Quote:


  Originally Posted by *trv* /img/forum/go_quote.gif 
_Hi Deano, stunning chasis! 

 What is that headphone plug?
 Name and model, I want to have buy same kind.
 Where can i order one?_

 

Let me google that for you


----------



## mugdecoffee

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I looked at Regulated DC filament supply circuit and I don't understand how it would work for the Bijou. (I expect powering the EZ81 heater using 6.3vac and use the DC circuit to power the amp tubes) Best case each Schottky doide will drop ~0.5v each so for each cycle I would expect a drop of at least 1 volt. The total filtered voltage would be ~5.3v or less going to the regulator (already low for the heaters). I didn't look at the specs for the regulator but lets say the regulator is an LDO and the dropout voltage is ~0.5v so the most you could deliver to each heater (regulated) would be ~4.8v which seems quite low. What am I missing?_

 

When you rectify AC, you get a DC voltage thats higher by a factor of square root 2 (~1.4). In this case, 6.3VAC*1.4=8.8VDC which is enough overhead for the diodes and regulator.


----------



## regal

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_When you rectify AC, you get a DC voltage thats higher by a factor of square root 2 (~1.4). In this case, 6.3VAC*1.4=8.8VDC which is enough overhead for the diodes and regulator._

 

Usually its not.


----------



## luvdunhill

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_When you rectify AC, you get a DC voltage thats higher by a factor of square root 2 (~1.4). In this case, 6.3VAC*1.4=8.8VDC which is enough overhead for the diodes and regulator._

 

one correction. The 6.3VAC assumes that the transformer is fully loaded. If this isn't the case, then that voltage will be higher. This can either be beneficial (allowing a bit more headroom to avoid using a LDO) or it can be annoying, in that you might have an extra watt or two of heat to dissipate.


----------



## balderon

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_When you rectify AC, you get a DC voltage thats higher by a factor of square root 2 (~1.4). In this case, 6.3VAC*1.4=8.8VDC which is enough overhead for the diodes and regulator._

 

I forgot about converting the voltage from RMS to peak. 
	

	
	
		
		

		
		
	


	




 Thanks


----------



## gabriel-dan

The 370DAX or 370DAZ universal transformers recomended by cavalliaudio is out of stock at Mouser. 
 Any equivalent universal transformer not too $$$ that I can use?


----------



## CountChoculaBot

I bought Regal's bijou and I must say it sounds fantastic (thanks again Regal =]).

 There's a really, really weird thing going on with only the 6N6P tubes, though. Whenever I hook it up to a DAC that's connected to a PC with Coaxial or USB, there's a very loud constant humming noise (equivalent to music playing at mediumish levels) and I can hear interference from my mouse cursor moving (the humming is present even when I have the DAC off and the DAC's power cord disconnected). When I hook it up via optical, there's no noise at all and it's dead quiet as it should be. I've tried this with two computers (my PC and my laptop) and two completely different DACs. With the ECC99 tubes, this problem is not apparent and I notice no difference in background noise between coaxial/usb and optical. However, I seem to prefer 6N6P, so going ECC99 would be less than preferable. 

 Would my problem be rectified by simply buying a new pair of 6N6P's? I'm unsure if this is the route to go, since the tubes are 100% great when fed optical, which tells me the tubes are non-defective.


----------



## pabbi1

Quote:


  Originally Posted by *gabriel-dan* /img/forum/go_quote.gif 
_The 370DAX or 370DAZ universal transformers recomended by cavalliaudio is out of stock at Mouser. 
 Any equivalent universal transformer not too $$$ that I can use?_

 

Have a look at Angela Instruments Online Catalog - Home - they are usually cheaper than Mouser on Hammond as well as having copious stock.


----------



## gabriel-dan

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Have a look at Angela Instruments Online Catalog - Home - they are usually cheaper than Mouser on Hammond as well as having copious stock._

 

Thanks pabbi1,
 That's a good site to source parts.


----------



## regal

Quote:


  Originally Posted by *CountChoculaBot* /img/forum/go_quote.gif 
_I bought Regal's bijou and I must say it sounds fantastic (thanks again Regal =]).

 There's a really, really weird thing going on with only the 6N6P tubes, though. Whenever I hook it up to a DAC that's connected to a PC with Coaxial or USB, there's a very loud constant humming noise (equivalent to music playing at mediumish levels) and I can hear interference from my mouse cursor moving (the humming is present even when I have the DAC off and the DAC's power cord disconnected). When I hook it up via optical, there's no noise at all and it's dead quiet as it should be. I've tried this with two computers (my PC and my laptop) and two completely different DACs. With the ECC99 tubes, this problem is not apparent and I notice no difference in background noise between coaxial/usb and optical. However, I seem to prefer 6N6P, so going ECC99 would be less than preferable. 

 Would my problem be rectified by simply buying a new pair of 6N6P's? I'm unsure if this is the route to go, since the tubes are 100% great when fed optical, which tells me the tubes are non-defective._

 

Here is some reading for you. I never had a problem with USB or coax but my DAC has a pulse transformer on the input to break any ground loops from the computer.

Digital audio and groundloops


----------



## CountChoculaBot

Thanks for identifying the issue. Looks like I have a few options here, though I may just end up being lazy and stick with optical.


----------



## nattonrice

Quote:


  Originally Posted by *gabriel-dan* /img/forum/go_quote.gif 
_Thanks pabbi1,
 That's a good site to source parts._

 

Indeed~
 They have an awesome selection of Hammond goodies.
 Communication is a bit meh though.


----------



## mugdecoffee

Quote:


  Originally Posted by *CountChoculaBot* /img/forum/go_quote.gif 
_Thanks for identifying the issue. Looks like I have a few options here, though I may just end up being lazy and stick with optical._

 

I was just dealing with this problem and solved it with a ground loop breaker which is pretty simple to do if you're up for it. Just a resistor and capacitor, some wire, and some heatshrink and you're good. A page or two back there are more details. I'm pretty sure new tubes won't help.


----------



## balderon

I have moved a couple things around in my chassis and made room to add the DC filaments. I expect the parts by the weekend and hopefully will be free of hum shorty thereafter. 

 Has anyone else completed this change?


----------



## funch

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I looked at Regulated DC filament supply circuit and I don't understand how it would work for the Bijou. (I expect powering the EZ81 heater using 6.3vac and use the DC circuit to power the amp tubes) Best case each Schottky doide will drop ~0.5v each so for each cycle I would expect a drop of at least 1 volt. The total filtered voltage would be ~5.3v or less going to the regulator (already low for the heaters). I didn't look at the specs for the regulator but lets say the regulator is an LDO and the dropout voltage is ~0.5v so the most you could deliver to each heater (regulated) would be ~4.8v which seems quite low. What am I missing?_

 

It seems as if you are correct. I just installed the Millet-designed DC filament
 supply, and using the 270DAX (3.5A heater supply current) to drive 2 6H30's
 and 2 ECC99's, I can only get 5.98V out under load. 

 When I remove the ECC99's to reduce the load, I can get 6.3V easily, 
 so I'm assuming that a heater tranny with a higher current rating, say around
 5A would work OK.


----------



## balderon

Quote:


  Originally Posted by *funch* /img/forum/go_quote.gif 
_It seems as if you are correct. I just installed the Millet-designed DC filament
 supply, and using the 270DAX (3.5A heater supply current) to drive 2 6H30's
 and 2 ECC99's, I can only get 5.98V out under load. 

 When I remove the ECC99's to reduce the load, I can get 6.3V easily, 
 so I'm assuming that a heater tranny with a higher current rating, say around
 5A would work OK._

 

I am sorry it did not workout. 
	

	
	
		
		

		
			





 Did you omit the choke for your testing? I am hoping to squeak by using the 270FX 5A filament winding combined with 0.5 forward voltage drop diodes plus a LDO regulator. If this does not work I will be forced to go to plan B (4A Power Brick)


----------



## funch

I've ordered a Hammond 166N6 4A CT tranny from AES. That 'should' take
 care of the main boards. I'm going to use the 270 for the EZ81 which 
 again 'should' make the 270 run a lot cooler. We'll see, and I'll report back.


----------



## TimJo

Just wanted to add a link to Ant1Xr1st's post with the OCL version of the Bijou that he was discussing with Alex a little while ago...

OCL Bijou in progress


----------



## runeight

There is no way to stop antichrist from building this amp for his own purposes. But I will have a chat with him about commercializing it.


----------



## Ant1Xr1st

*TimJo*, *runeight*, thank you guys 
	

	
	
		
		

		
		
	


	




 Shematics and pcb's [size=xx-small](for laser printer toner transfer)[/size] will be published soon.


----------



## balderon

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I am sorry it did not workout. 
	

	
	
		
		

		
		
	


	




 Did you omit the choke for your testing? I am hoping to squeak by using the 270FX 5A filament winding combined with 0.5 forward voltage drop diodes plus a LDO regulator. If this does not work I will be forced to go to plan B (Power Brick)_

 

I ended up with the same result as funch. 
	

	
	
		
		

		
		
	


	




 The maximum output of the DC filament supply was only 6.09v driving 2xECC99 and 2x6DJ8, even with the higher filament current (and voltage). In order to achieve the desired voltage I could *again* move things around in my chassis and squeeze in a separate transfo. I am not in favor of this and I am going to plan B.


----------



## funch

Wow, even 5A wouldn't work. Makes me doubt my choice of the separate
 4A tranny I ordered from AES (Hammond 166N6). Maybe I shoulda' gone 
 with the 6A one (166Q6).

 The new one should be here in a day or two. I'll report back with my results.


----------



## fishski13

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I have moved a couple things around in my chassis and made room to add the DC filaments. I expect the parts by the weekend and hopefully will be free of hum shorty thereafter. 

 Has anyone else completed this change?_

 

i have everything for DC heaters, but am tied up with other projects now. i have no noise issues, but since i have a chassis that's large enough for my former balanced configuration, i figure i might as well fill up some of the space 
	

	
	
		
		

		
		
	


	




. i still have yet to order a FPE faceplate.

 btw, my Bijou sounds fantastic with DT990/600ohm.


----------



## Ant1Xr1st

It's works. Oh shi.. its really works! 
	

	
	
		
		

		
		
	


	




 But there is some hum problem. I will try to fix it soon. 
 Rmaa test [size=xx-small](pcm2702 dac and notebook built-in adc)[/size]




 Eagle schematics and pcb here [size=xx-small](use it on your own risk, not for novice diyers)[/size]
 More pics here


----------



## funch

My tranny came in today, I hooked it up, and ........ epic fail!!
	

	
	
		
		

		
		
	


	



 Could only muster 5.37VDC under load.

 So, on to plan C. I'll build another DC regulator, use the 270 thru 
 one to power the EZ81 and ECC99's. and use the 166N6 thru the
 second to power the 6H30's. Heck, I might even reinstall the 1A
 tranny for the EZ 81 too and use the 270 just for the ECC99's.

 Gotta check to see how much room I've got. By hook or crook, this
 is gonna work!!@#$%


----------



## balderon

Everything was going well with the TDK-Lambda power brick. I used a 25W resistor to simulate the 6.3vdc @ 3A heater load. I adjusted the regulator when plenty of reserve power. Nothing was smoking and the diode bridge and regulator was slightly warm. I then connected the supply to the tubes, double checked my wiring, and turned on the supply. Nothing happened. I sadly discovered the short circuit protection was triggering when I turned on the power. 
	

	
	
		
		

		
		
	


	




 I am sorry to admit that I will also pursue plan C. My latest and last iteration is to replace the power brick with a low profile 10 VAC @ 4.8A transfo. The transfo is about the same size as the power brick so I'll be able to squeeze it into my chassis. As before I will use the DC filament circuit to power the amp tubes and the 270FX for the EZ81.


----------



## regal

Those of you with DC heaters, how are you lifting the DC? I forget the proper way to do this with DC and can't find any info anywhere.


----------



## TimJo

In the Morgan Jones book, _Valve Amplifiers_, he uses something he named the THINGY which is a pair of emitter followers, using MPSA42's. The output voltage is determined by a voltage divider across the HT rails. The output is then introduced to the either side of the DC supply through a pair of resistors. 

 In that example he used a pair of emitters because he needed two DC supplies, each elevated at a particular level, based on the tube's max cathode to grid voltage, and where the tube was used in the amplifier. I see no reason why you couldn't use a single emitter follower here, set to say 50 volts, provided that doesn't exceed the ratings of the particular tubes you are using.

 Adumus brought this up in November (wrt ac heaters using the Regal Mod) and here is what Alex said regarding 6922's.

http://www.head-fi.org/forums/f6/bij...ml#post6131726


----------



## MoodySteve

It’s been a long time coming, but ater a few weeks of meticulous fastening and wiring, my Bijou finally came to life late last night. This was by far the most involved I’ve been in wiring (spoiled by PCBs and backplanes) and the heater wiring was a bear to get right. 

 First - my brief, 5-minute listening impression was quite good. I would describe the sound as ‘fun’ and ‘alive’ – I think it may pair well with Sennheisers.

 I do, however, have one concern. When B+ is hooked up to both amplifier boards, it drops to BARELY under 250V (we’re talking like 248-249V), and turning the trimmer to increase it has no effect. When only ONE of the amplifier boards is plugged in (it doesn’t matter which one), this is no longer the case – turning the trimmer does increase the B+ past 250V. Since I’m so close to the proper voltage and the sound is good, I’m not sure if this is worth being concerned about, but I can’t figure out what’s going on. Any thoughts?

 Also, I noticed that in the NFB wiring diagram on the Cavalli site, it instructs the builder to connect the two wires to the two legs of the pot and then short the wiper to one or the other leg. I can see how this will allow for relatively easy switching of the NFB pot configuration (i.e. it would be easy to switch full-CCW from ‘maximum NFB’ to ‘minimum NFB’) but is this crucial? I connected the wires to one leg and the wiper, and NFB works as expected. Electrically, I don’t see why it would be crucial, but I’ve had subtle wiring changes result in unexpected changes, so I figure it can’t hurt to ask!

 I want to offer yet another hearty thanks to Alex Cavalli for sharing this awesome design with the community, the prototyping team for helping make the project a reality, and Regal for the Regal mods.

 Due to receiving two faulty headphone jacks in a row (my case has thick wood panels) I don’t have the jack securely fastened, but as soon as everything is as it should be I’ll be posting pics.


----------



## MoodySteve

Duplicate Post


----------



## balderon

Great news MoodySteve. Congrats!

 I have been working on my build for quite some time and it is nearing completion. The case is finished and am working on completing the DC heater circuit. I expect to post pics in a couple weeks.

  Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_I do, however, have one concern. When B+ is hooked up to both amplifier boards, it drops to BARELY under 250V (we’re talking like 248-249V), and turning the trimmer to increase it has no effect. When only ONE of the amplifier boards is plugged in (it doesn’t matter which one), this is no longer the case – turning the trimmer does increase the B+ past 250V. Since I’m so close to the proper voltage and the sound is good, I’m not sure if this is worth being concerned about, but I can’t figure out what’s going on. Any thoughts?_

 

This is common especially when using the 270/370DAX transfo. In my case the B+ dropped even lower once I installed the Regal mod. I ended up changing out to a higher rating transfo. If I recall correctly, Alex posting a message stating B+ the range of 240's-250 is acceptable.

  Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_Also, I noticed that in the NFB wiring diagram on the Cavalli site, it instructs the builder to connect the two wires to the two legs of the pot and then short the wiper to one or the other leg. I can see how this will allow for relatively easy switching of the NFB pot configuration (i.e. it would be easy to switch full-CCW from ‘maximum NFB’ to ‘minimum NFB’) but is this crucial? I connected the wires to one leg and the wiper, and NFB works as expected. Electrically, I don’t see why it would be crucial, but I’ve had subtle wiring changes result in unexpected changes, so I figure it can’t hurt to ask!_

 

I think the reason Alex ties the wiper and one leg together is to ensure the NFB circuit will always have a signal path. Depending on how you connect the leg and wiper you could have an open circuit when the pot is turned fully CW or CCW. I would expect a significant amount of induced noise to be present if the open was at the input of V1A. Also I do believe if you choose to install the NFB circuit you must have a closed signal path for proper operation.

  Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_Due to receiving two faulty headphone jacks in a row (my case has thick wood panels) I don’t have the jack securely fastened, but as soon as everything is as it should be I’ll be posting pics._

 

Everyone likes to see pics!


----------



## dean0

Going to be Regal modding my Bijou this weekend and I have encountered a problem.
 The EZ81 is aprox 1cm taller than EZ80, and its too tall for my chassis. 
 Are all EZ81 manafactures the same height? (currentley using EZ81 Tesla 32) 
 Thanks 
 dean0


----------



## balderon

Quote:


  Originally Posted by *dean0* /img/forum/go_quote.gif 
_Going to be Regal modding my Bijou this weekend and I have encountered a problem.
 The EZ81 is aprox 1cm taller than EZ80, and its too tall for my chassis. 
 Are all EZ81 manafactures the same height? (currentley using EZ81 Tesla 32) 
 Thanks 
 dean0_

 

None that I could find.


----------



## GWorlDofSPACE

I have finished my whit regals and other modes. Its sounding just amazing, the vocals are to die for!!! This is a great add to B22. 
 ROmantic song are now really romantic)) 
 I will post some pictures as I find decent knobs for it.

 My voltage is 250-251 and I could have adjusted more.


----------



## GWorlDofSPACE

I am burning it in, so it has around 20 hours of playing. I am a little worry about the temperature of the 370DAX. I cant hold my fingers on it for more then a few sec. Is this normal? I know that tube amps are getting hot!!!


----------



## balderon

Quote:


  Originally Posted by *GWorlDofSPACE* /img/forum/go_quote.gif 
_I am burning it in, so it has around 20 hours of playing. I am a little worry about the temperature of the 370DAX. I cant hold my fingers on it for more then a few sec. Is this normal? I know that tube amps are getting hot!!!_

 

I was experiencing the same problem and was uncomfortable with the excessive heat. I solved it by changing out the transfo. Look at this post and the several that follow.


----------



## fishski13

Quote:


  Originally Posted by *GWorlDofSPACE* /img/forum/go_quote.gif 
_I am burning it in, so it has around 20 hours of playing. I am a little worry about the temperature of the 370DAX. I cant hold my fingers on it for more then a few sec. Is this normal? I know that tube amps are getting hot!!!_

 

you could add the cap multiplier mod to the PS as well. i have mine P2P on perfboard and no thermal issues with my 370DAZ.


----------



## GWorlDofSPACE

I measured the surface temp and its 55-60 C. I think this is normal for a tube amp and whit regals modes. What do you think guys?


----------



## funch

I just finished setting up dual DC heaters using the 270DAX for the 6H30's,
 a Hammond 166N6 for the ECC99's, and the same 1A tranny for the EZ81.
 So that's 3 trannies in all. The good news is I could get 6.30VDC to each
 audio tube, but now I've got some pretty bad buz/hum going on.

 I'm probably in over my head with all this, and since the amp was working
 with AC heaters, I'm going back to them.


----------



## fishski13

i have parts for a full-wave bridge rectified Pi filter for DC heaters but am interested in a regulated design for 2.8A. i am planning on using the 6.3V AC heater secondaries for the EZ81. my amp proper tubes include 2 ECC99 and 2 6n1p. any suggestions? 

 thanks!


----------



## balderon

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_Those of you with DC heaters, how are you lifting the DC? I forget the proper way to do this with DC and can't find any info anywhere._

 

I came across two methods to elevate the DC heater to satisfy the heater-to-cathode voltage.

 1) A floating heater power supply, by “grounding” the heater power supply via a 0.1μF film or ceramic capacitor. The capacitor will charge up through the leakage current between heater and cathodes. The article mentioned this method is easy, cheap to implement, and it is often quite effective in reducing hum.

 2) Reference the heater power supply to a voltage equal to one fourth the B+ voltage; for example, 62.5v, when using a 250V power supply. The ¼ B+ voltage ensures that both top and bottom triodes see the same magnitude of heater-to-cathode voltage.

 I am planning on trying option #1 tomorrow and will report back on my experiences.


----------



## balderon

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i have parts for a full-wave bridge rectified Pi filter for DC heaters but am interested in a regulated design for 2.8A. i am planning on using the 6.3V AC heater secondaries for the EZ81. my amp proper tubes include 2 ECC99 and 2 6n1p. any suggestions? 

 thanks!_

 

Both funch and I could not get sufficient power from the rectified 6.3V secondary to sufficiently power all four tubes. I ended up ordering a different transfo to power the filaments. The parts should be delivered tomorrow.


----------



## regal

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_i have parts for a full-wave bridge rectified Pi filter for DC heaters but am interested in a regulated design for 2.8A. i am planning on using the 6.3V AC heater secondaries for the EZ81. my amp proper tubes include 2 ECC99 and 2 6n1p. any suggestions? 

 thanks!_

 

For regulated DC source a 50VA dual secondary 9V transformer and build a separate regulator/circuit for the Ecc99 & 6n1p. Use the Lm1085 regulators with case mounted heatinks, also elevate the DC with a divider from the powersupply. A lot of money and time.

 IMO DC heating is unnecessary for this amp, this in truly an amp for high ohm phones where you will never hear heater hum. The SOHAII is a much better choice for Grados and the like.


----------



## balderon

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_IMO DC heating is unnecessary for this amp, this in truly an amp for high ohm phones where you will never hear heater hum. The SOHAII is a much better choice for Grados and the like._

 

The reason I want to change to DC heaters is I do hear a slight hum (independent of the tubes) in both channels with my HD-650.


----------



## regal

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_The reason I want to change to DC heaters is I do hear a slight hum (independent of the tubes) in both channels with my HD-650._

 

I had no hum with HD650's, do you have a picture of the amp's insides?


----------



## GWorlDofSPACE

Do I really need to measure the voltage at the input to the phase splitter? How to do this?

 I have found a good source for Mcaps and want to know if somebody has tried M-tubecaps. There are 100-200uF available from the source?


----------



## adamus

in what position, the output caps? 

 I can only imagine an improvement of lytics, but the proof is only in the pudding!


----------



## GWorlDofSPACE

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_in what position, the output caps? 

 I can only imagine an improvement of lytics, but the proof is only in the pudding!_

 

Yes the output caps.


----------



## pabbi1

With the "Amphead mod", have never heard any noise with the hd600 / hd650 / hd800, and used all extensively with my (balanced) Bijou.

 Of course, I have not done the "Regal mod" either...


----------



## fishski13

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_For regulated DC source a 50VA dual secondary 9V transformer and build a separate regulator/circuit for the Ecc99 & 6n1p. Use the Lm1085 regulators with case mounted heatinks, also elevate the DC with a divider from the powersupply. A lot of money and time.

 IMO DC heating is unnecessary for this amp, this in truly an amp for high ohm phones where you will never hear heater hum. The SOHAII is a much better choice for Grados and the like._

 

i've looked at the LM1085 and see that it's rated for 3A, i need 2.8A, so we're good here. but what about diodes/rectifiers? i have some 5A rated schottky diodes, but do i need to go higher with a block-type rectifier. how much current is passing through the bridge?


----------



## fishski13

Quote:


  Originally Posted by *GWorlDofSPACE* /img/forum/go_quote.gif 
_Yes the output caps._

 

i bought my M-caps here: Hifi, Car Audio, Pro Audio and DIY - Soundlabs Group Online this was before the economy went in the toliet and i have no idea what the exchange rate would be now.


----------



## funch

Last (I hope!) update.

 I went back to AC heaters, using the 166N6 tranny for the amp boards,
 and the 270 for the EZ81. Kept Amphead's mod. The tiny hum that I had
 in one channel is hasta la bye-bye. Dead quiet. I'll have to agree with
 Regal that AC heaters are fine for the Bijou.

 BTW, I use shielded milspec wire for the heater wiring that I got from
 good ol' John. 

 Uh-oh! I'm listening to the amp as I type, and just checked the heater
 voltage while it's under load. It's 6.66V. Should I be concerned about 
that number? 
	

	
	
		
		

		
			








 Damn, I forgot how good this thing sounds.


----------



## Ant1Xr1st

*funch*, a bit high heater voltage is good for sound imho. but it should never be lower then 6.1v - you will get a dirty sound and noise. 
_*6.66 its a bit overkill, try to add a resistance to get a 6.5_


----------



## Parafeed

Quote:


  Originally Posted by *Ant1Xr1st* /img/forum/go_quote.gif 
_a bit high heater voltage is good for sound imho. but it should never be lower then 6.1v - you will get a dirty sound and noise._

 

Yet another pearl of wisdom on Head-Fi! 

 I better throw away all those tube manuals that list 6.3V as an "average" value and state +/- 10%, +/- 5%, or 6.0-6.6V as being an acceptable range for a 6.3V tube. 

 As for getting "a dirty sound and noise" with < 6.1V, I frequently use 6.0V regulated DC for 6.3V tubes and I've not heard any ill effects. 

 I'd try to stay within 5% of the nominal 6.3V for longevity. Ignoring any subjective discussions like SQ, too high or too low a voltage will affect tube life.


----------



## Ant1Xr1st

I have hear such heater voltage difference with soviet 6N1P and 6S45P tubes.


----------



## fishski13

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_Both funch and I could not get sufficient power from the rectified 6.3V secondary to sufficiently power all four tubes. I ended up ordering a different transfo to power the filaments. The parts should be delivered tomorrow._

 

sorry, i haven't searched, but do you have schematic and how much current are the heaters using up for your tubes?


----------



## balderon

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I had no hum with HD650's, do you have a picture of the amp's insides?_

 

This exercise in adapting to a regulated DC heater circuit has uncovered an issue with my heater wiring. The left channel 6DJ8 had the heater wiring reversed. I don't know if the phase difference contributed to the slight hum I was experiencing on that same channel. 
	

	
	
		
		

		
			





 One thing for certain is I disconnected the all heater wires in preparation of installing the regulated DC circuit. This forced me to examine all heater connections. I cut off the ends of the wires and made fresh connections. Perhaps I had bad connection as well. In any case the slight hum I was experiencing has disappeared and has not returned even when moving the wires while listening with the amp power.

 I will post pics after I secure the wiring and reinstall some add-on components that were not a source of the hum.


----------



## fishski13

Quote:


  Originally Posted by *Ant1Xr1st* /img/forum/go_quote.gif 
_I have hear such heater voltage difference with soviet 6N1P and 6S45P tubes. 
	

	
	
		
		

		
		
	


	


_

 

i've also read that some people prefer a lower heater voltage at around 6.0V. i wonder if these preferences could be attributed by how a tube in situ is biased wrt the load-line and the transconductance of that tube. btw, i've never compared differences.


----------



## balderon

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_sorry, i haven't searched, but do you have schematic and how much current are the heaters using up for your tubes?_

 

6DJ8 : 2 x 0.365A = 0.73A
 JJ ECC99 : 2 x 0.8A = 1.6A

 The circuit I was planning to use is Pete Millett Regulated DC filament supply circuit. As I no longer have a need for this circuit the unused parts with the exception of a heat sink and choke are available for sale. At cost of course.


----------



## fishski13

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_6DJ8 : 2 x 0.365A = 0.73A
 JJ ECC99 : 2 x 0.8A = 1.6A

 The circuit I was planning to use is Pete Millett Regulated DC filament supply circuit. As I no longer have a need for this circuit the unused parts with the exception of a heat sink and choke are available for sale. At cost of course. 
	

	
	
		
		

		
		
	


	


_

 

do you have a part number for the choke? i might be interested.


----------



## balderon

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_do you have a part number for the choke? i might be interested._

 

Sorry, I do not nor did I did try searching for it.

 EDIT: I took a few moments and figured out what the part number / specs for the choke. Unfortunately it is now an obsolete part. Pulse Engineering PE-96173


----------



## dean0

Update;

 - Bugle Boy 6DJ8 Valves 
 - EZ81 P/S
 - Regal Mods
 - 100k Stepped Attenuator


----------



## funch

Very nice, dean0. Any pics with the top on?


----------



## balderon

Nice build Dean0! Did you resolve the height problem with the EZ81?


----------



## dean0

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_Nice build Dean0! Did you resolve the height problem with the EZ81?_

 

No not yet, just been running without the top. Iam thinking about mounting it sideways internaly, off the pcb with a shield, would this cause any problems?
 thanks


----------



## adamus

shouldnt cause an issue if you can fit it. 

 other option is to cut a hole in the top.


----------



## dean0

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_shouldnt cause an issue if you can fit it. 

 other option is to cut a hole in the top._

 

I would cut a hole but the position it is in would look wrong (vented area), and the other holes are cnc cut...


----------



## trv

Finished building Bijou last night.
 I have to say it sounds mighty impressive right from the start.
 No hums, buzzes etc. Wow. I´m happy 
	

	
	
		
		

		
		
	


	




 Will do Regal mod after break in, and will change the tubes for Telefunken or Mullards that i use in all my valveamps

 I use Sennheiser 650 headphones only, so i did leave out the NFB


----------



## rolotube

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_For regulated DC source a 50VA dual secondary 9V transformer and build a separate regulator/circuit for the Ecc99 & 6n1p. Use the Lm1085 regulators with case mounted heatinks, also elevate the DC with a divider from the powersupply. A lot of money and time.

 IMO DC heating is unnecessary for this amp, this in truly an amp for high ohm phones where you will never hear heater hum. The SOHAII is a much better choice for Grados and the like._

 

I agree with regal's comments re hum. I'm using amphead's mods (100R resistors across heater supply with CT to earth) & no DC float off HV line. Absolutely dead quiet. IMO, careful attention to layout & quality wire will go a long way towards achieving a silent amp. I have considered DC heaters but doubt the improvements, actual or perceived, would be detectable.

 The SOHA II may be better for other phones but mine works superbly with my HD650's, although I'd have to say, not quite in the same class as the Bijou.


----------



## rolotube

Quote:


  Originally Posted by *GWorlDofSPACE* /img/forum/go_quote.gif 
_Do I really need to measure the voltage at the input to the phase splitter? How to do this?

 I have found a good source for Mcaps and want to know if somebody has tried M-tubecaps. There are 100-200uF available from the source?_

 

I'm using Tubecaps throughout. In the PS, C1 (200uF), C4, 5, 6 (47uF) with choke mods. In the amp, I'm running a 200uF as the output cap, no bypass. Results are excellent, much better than stock electros. Others have used 330uF Mundorf MKP on the output. This may well be a better solution than the Tubecap, but is twice the price.


----------



## S3TUP

Hi! I'm building the Bijou right now and got a question:

 I use a toroidal transformer from Antek-inc, and it has double 6.3v rails 3.5a each.
 Should i take one winding for PSU and other one for amps, or that doesn't matters much as it's just a heater supply?


 It's going to be all-russian tube Биджо(russian Bijou 
	

	
	
		
		

		
		
	


	




 ) (6n1p + 6n6p for now, with 6n23p instead of 6n1p in near future).
 + ladder attuneator 
 + arduino micro controller 
 + nixie volume display.


----------



## adamus

it matters. 

 look on the schematic, the there is a voltage divider that puts about +40vdc bias on the heater lines. This is required if you look at datasheets (although anyone doing ampheads mods is not doing this).

 You could either parallel them for 7 amps (which means you will probably have too high a voltage). ot just just one (ez81 ~ 1amp, 2x 6dj8 ~ 0.6amp, 2X 6n6p ~1.6amp = 3.2amps @6.3v. 

 If the tranformer runs a bit hot, then parallel them (taking care of phase).


----------



## breizheau

After a break, i have decided to start again to work on the Bijou. But this thread now is loooooooooong.
 I am sure not sure to know all the updates about this amp. Exept the "Amphead's Heater Mods" and "Reagl's mod" that i have found on Cavalli website.
 What about the capacitors ?????? Could you do a "shorcut" for the different tests already done about values, caps, brands please ?






 Olivier


----------



## pabbi1

Does anyone have observations about using Grados, or other low impedence phones, with the Bijou?


----------



## adamus

I do, but it may be controversial. 

 I thought it was bad with grados, didnt like the sound at all. 

 with high impedance phones the bijou is lovely and impressive. With low impedance i think sohaII or the CTH actually sound 'better' (subjective opinion only!)


----------



## regal

Quote:


  Originally Posted by *breizheau* /img/forum/go_quote.gif 
_After a break, i have decided to start again to work on the Bijou. But this thread now is loooooooooong.
 I am sure not sure to know all the updates about this amp. Exept the "Amphead's Heater Mods" and "Reagl's mod" that i have found on Cavalli website.
 What about the capacitors ?????? Could you do a "shorcut" for the different tests already done about values, caps, brands please ?





 Olivier_

 

As mentioned earlier use this amp with 300 ohm or higher headphones. Remove the NFB resistor. Then for the large output caps use 100uf motor run oil caps bypassed with russian Ky40 1uf caps. Both caps are found on ebay for cheap, sound is hugely improved over using electrolytic caps.


----------



## GWorlDofSPACE

Guys,
 I was wondering how to configure the bijou PSU to deliver 300V anode power 100mA?
 Can I just connect a 310-320V transformer? Has someone experimented whit higher anode voltage? Is I know you get different flavour of sound not?


----------



## adamus

why?

 00ma @300v over 4 tubes = ~ 25 per tube = something like an EL84 (which would want a bit more current.


 not a bijou anymore.


----------



## GWorlDofSPACE

Understand... I am thinking to make an tube 6j8d output for my future DAC.
 The PSU from Bijou is very good and the EZ81 can deliver 150mA. I need 100mA.


----------



## adamus

why do you need 100ma?

 100ma @ 300 v = 30watts?

 sure your calcs are correct?

 6dj8 typically run 1-10ma. are you running many?


----------



## breizheau

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_As mentioned earlier use this amp with 300 ohm or higher headphones. Remove the NFB resistor. Then for the large output caps use 100uf motor run oil caps bypassed with russian Ky40 1uf caps. Both caps are found on ebay for cheap, sound is hugely improved over using electrolytic caps._

 

Thx. I'll do ASAP. I still have to find time to work on it.


----------



## mugdecoffee

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_I do, but it may be controversial. 

 I thought it was bad with grados, didnt like the sound at all. 

 with high impedance phones the bijou is lovely and impressive. With low impedance i think sohaII or the CTH actually sound 'better' (subjective opinion only!)_

 

I very much agree. I think my HF-2s sound better out of my iPod than my Bijou. I also agree about the CTH. Just built mine and it drives them quite well.


----------



## regal

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_I very much agree. I think my HF-2s sound better out of my iPod than my Bijou. I also agree about the CTH. Just built mine and it drives them quite well._

 

I agree also, The Bijou was my dream amp when my facorite headphones were Sextetts (600 ohm) and Senns (300 ohms), then I heard Grados for the first time and fell in love, but the Bijou just wasn't a good match for them. I built a SOHA II with a high tail current mod and it does a great job with Grados.


----------



## rolotube

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Does anyone have observations about using Grados, or other low impedence phones, with the Bijou?_

 

HD650's (300 ohms) sing beautifully with my Bijou, K701's (62 ohms) are, at best, ordinary. As noted by regal, the latter work better on the SOHA II but don't capture the magic of the Senns, at least not to my ears.


----------



## UKToecutter

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Ok, caps packaged for all who gave me an address - James, Randy, Husky - need mailing info.

 Again, just donate the $$$ directly to Head-fi.

 Still over 100 left... 
	

	
	
		
		

		
		
	


	


_

 

Pabbi1.

 Just reading through the thread and came across this.

 Do you have any of these caps left???


----------



## pabbi1

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_HD650's (300 ohms) sing beautifully with my Bijou, K701's (62 ohms) are, at best, ordinary. As noted by regal, the latter work better on the SOHA II but don't capture the magic of the Senns, at least not to my ears._

 

Mine too... hd600, hd650 and hd800.

  Quote:


  Originally Posted by *UKToecutter* /img/forum/go_quote.gif 
_Pabbi1.

 Just reading through the thread and came across this.
 Do you have any of these caps left???_

 

I do indeed - just ping me with an address.


----------



## mugdecoffee

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_HD650's (300 ohms) sing beautifully with my Bijou, K701's (62 ohms) are, at best, ordinary. As noted by regal, the latter work better on the SOHA II but don't capture the magic of the Senns, at least not to my ears._

 

I personally thought the bijou complemented my K701s nicely though I was using them with more negative feedback than with other higher impedance phones.


----------



## luvdunhill

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_SOHA II [doesn't] capture the magic of the Senns, at least not to my ears._

 

Interesting. I think I'd agree based on listening to orthos and Senns on pabbi1's SOHA II.


----------



## rolotube

Quote:


  Originally Posted by *mugdecoffee* /img/forum/go_quote.gif 
_I personally thought the bijou complemented my K701s nicely though I was using them with more negative feedback than with other higher impedance phones._

 

Perhaps I should qualify my comment - I'm not using any NFB on my Bijou, since I use the 650's virtually 100% of the time. In any event, I prefer the less analytical sound of the Senns to the forwardness of the AKG's, regardless of what's driving them. 701's would likely benefit from NFB with the Bijou.

 I've ordered an EHHA kit from Jeff Rossel so it will be interesting to compare & contrast all three in due course.

 pabbi, are the 800's as good as they are reported & reputed to be ie. significantly better than the 650's?? Do you think they are worth twice the price?


----------



## UKToecutter

Can someone check something for me please.

 The MOSFET's IRF820B are now obsolete. The FQP4N50_Q's are available.
 Alex's BOM says: "•Q1, Q2 are TO220AB package, SDG pinout orientation"
 On checking the device's datasheet, looking at the front (from left to right) the device is shown as GDS.
 Does the BOM orient it from the rear or the front?


----------



## pabbi1

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_Perhaps I should qualify my comment - I'm not using any NFB on my Bijou, since I use the 650's virtually 100% of the time. In any event, I prefer the less analytical sound of the Senns to the forwardness of the AKG's, regardless of what's driving them. 701's would likely benefit from NFB with the Bijou.

 I've ordered an EHHA kit from Jeff Rossel so it will be interesting to compare & contrast all three in due course.

 pabbi, are the 800's as good as they are reported & reputed to be ie. significantly better than the 650's?? Do you think they are worth twice the price?_

 

No question - I sold my hd600 and hd650 within a week of getting the hd800. Even though I love the balanced Bijou with the hd800, I am trying a push-pull topology with them as well. But, nothing will ever have the full hall sound stage the Bijou creates.


----------



## balderon

I have finally completed the casework on my Bijou. I tried many times and could not get a decent shot without the blue illumination around the front panel border washing out. 

More pictures found here.


----------



## UKToecutter

Wow, Just....... WOW

 Another beautiful Bijou creation


----------



## UKToecutter

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Mine too... hd600, hd650 and hd800.



 I do indeed - just ping me with an address._

 

Pabbi1

 I thought I'd sent you a PM but it doesn't seem to be in my sent items.

 Did you get it?


----------



## UKToecutter

Scratch that.

 I resent it


----------



## TimJo

Quote:


  Originally Posted by *UKToecutter* /img/forum/go_quote.gif 
_Can someone check something for me please.

 The MOSFET's IRF820B are now obsolete. The FQP4N50_Q's are available.
 Alex's BOM says: "•Q1, Q2 are TO220AB package, SDG pinout orientation"
 On checking the device's datasheet, looking at the front (from left to right) the device is shown as GDS.
 Does the BOM orient it from the rear or the front?_

 

GDS is from the front. The gate should match up with the dot on the device and the dot on the silk screen. Therefore the FQP4N50's should be installed just as the silk screen indicates.


----------



## UKToecutter

Quote:


  Originally Posted by *TimJo* /img/forum/go_quote.gif 
_GDS is from the front. The gate should match up with the dot on the device and the dot on the silk screen. Therefore the FQP4N50's should be installed just as the silk screen indicates._

 

Thanks TimJo.

 That'll do for me


----------



## pabbi1

Quote:


  Originally Posted by *UKToecutter* /img/forum/go_quote.gif 
_Pabbi1

 I thought I'd sent you a PM but it doesn't seem to be in my sent items.

 Did you get it?_

 

Got both actually, and actually replied to one... 

 Box secured, and I'll do customs forms tonight. Too bad the APC doesn't do Intl.


----------



## UKToecutter

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Got both actually, and actually replied to one... 

 Box secured, and I'll do customs forms tonight. Too bad the APC doesn't do Intl._

 

Pabbi,

 You're a diamond.

 Let me know who, how and how much.



 Andy


----------



## bhjazz

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I have finally completed the casework on my Bijou._

 

Wow, this amp really inspires some awesome casework! I can't keep track of all the amazing Bijous!


----------



## balderon

It's difficult to believe it has taken one year to complete the build. 
	

	
	
		
		

		
		
	


	




 The greatest amount of time was spent finishing the case work with the majority of the delays attributed to fabrication errors by Par-Metal (even with 8 pages of detailed CAD drawings). In any event I am pleased to have a finished product. Thanks everyone for your nice comments.


----------



## coffin

Hi
 My BiJou is close to finish, just changing the MOSFETs....
 I think I bought the bad Fets.

 cheers

 Coffin


----------



## coffin

Well, I replace both FETs now the pwr seems work fine!

 Some photos:

 Main module:


----------



## coffin

Next the power module.


----------



## coffin

The NFB control, I use a 2 deck/11 poles switch making a step control.


----------



## coffin

And this is a special shunt relay potentiometer, controled by a B type VR.


----------



## coffin

Finally everything is in place!






 I don't source 260-0-260V trans locally, only 250V is available. So I swap CRCRC to CLCLC, two chokes.


----------



## coffin

Take a look the finished BIJOU!











 The tubes currently used:
















 The sound is very sweet! No hum at all!


----------



## regal

Nice work, very creative NFB control.


----------



## MoodySteve

Nice work, coffin. We are using the same volume and NFB knobs. 
	

	
	
		
		

		
		
	


	




 Nice photography as well!


----------



## pabbi1

Coffin, that is what DIY is all about. Very nice work.

 Alas, I am now a former member of the club - there is a new member joining the club in Austin. And, no, not Runeight...


----------



## TimJo

Wow coffin, very nice work on your bijou. I can tell you put a lot of thought into the layout - nicely done!


----------



## coffin

Glowing tubes.....


----------



## fishski13

coffin,
 outstanding!!! all these great Bijous are making me feel guilty for not completing the finishing touches on mine.


----------



## breizheau

They make me guilty to haven't started yet to do the enclosure !!!!


----------



## coffin

Hi
 Here is making of Bijou, in Traditional Chinese:

Coffin's DIY Division: Bijou

 cheers

 Coffin


----------



## breizheau

After the "Gold regulator", the Bijou by Coffin !


----------



## bhjazz

Nice work, Coffin. And some neat personal touches for components as well. Very cool! 

 I plan on finally starting mine next week. Step 1: Initial purchases: trafo, stepped attenuator. Step 2: case design and layout...eek...


----------



## Ant1Xr1st

The second chanell is finished 
	

	
	
		
		

		
		
	


	




 It's sound very, very good with pcm2702 dac. 
 But there is some problems - its needed to mute the output when u turn off(and turn on of course) the amp, there is not loud but hearable "shot". Also, i hear such "shots"(but more loud) when my old fridge turns on or off.. I know what to do with first problem, bit with the last.. What kind of AC filter should i use?[size=xx-small]_ Ohh.. No, i cant just throw away the frige((_[/size]
 It's time to think about the case..


----------



## amphead

Nice work gentlemen! Good to see the Bijou's rolling on in. ^ Sorry to hear about your noise issue, I'll have to leave that for some of the great talent we have around here.


----------



## MoodySteve

Well, after more issues, setbacks and surprises than I'd care to enumerate, my Bijou is finally done. The case was designed, built and finished by me. I had a lot of help from my friend Dennis at O&M Engineering, who plasma cut some of the holes on the plate and welded and fly-cut my top plate after I accidentally converted a blind hole into a through hole. Naturally, as I was doing the wiring, I noted several improvements I could have made to the layout, but fortunately I do not hear hum or hiss. Live and learn!

*Features
*-Regal Mods
 -410µF photoflash Rubycons for C5
 -1µF Obbligato Golds for C6
 -10µF Solen Polypropylene for C1
 -Alps RK40 Attenuator
 -Shielded signal wiring

 I'll need a lot more listening time before I comment on the sound, but suffice to say I am very pleased. I hear what people mean when they describe the sound as alive, vibrant and lush.

 Here's the last rendering I had done of the design:






 And here's how it came out:


----------



## DeadBoys

Awesome Bijou mate, glad to hear that you got it working after such a long time in development. Don't think I've ever seen the 1/4" jack before, it fits in really well!

 I'll be waiting for opinions with your 650's


----------



## balderon

@MoodySteve - Another debut of a fine Bijou! Your build looks just as you have designed it. Awesome job!


----------



## UKToecutter

Very nice. Very nice indeed !!


----------



## MoodySteve

Quote:


  Originally Posted by *DeadBoys* /img/forum/go_quote.gif 
_Awesome Bijou mate, glad to hear that you got it working after such a long time in development. Don't think I've ever seen the 1/4" jack before, it fits in really well!

 I'll be waiting for opinions with your 650's 
	

	
	
		
		

		
		
	


	


_

 

Thanks! That headphone jack is a 'deep panel stereo' headphone jack, and I would heartily recommend that all my DIY brothers and sisters *avoid these* (at least the gold-plated ones, can't speak for the nickel-plated Neutriks). I tried two types, one off-brand and one Switchcraft. The off-brand shorts the right channel to ground (meaning that the right channel tab is bent in the wrong place - all three pieces I tried had the same problem) and the Switchcraft had intermittent contact on the left channel because it allowed the plug to insert too deep into the jack. The off-brand was not repairable, but the Switchcraft was usable after I glued a gold washer to the front that shimmed the plug the correct amount.

 That is just ONE of the many adventures I had in building my Bijou. I hope that no other builder has stumbled so hard on such an irrelevant part as the headphone jack.


----------



## simwells

I'm thinking of buying the glassjar kit of this, but am struggling to find where (in the UK) i could get the PSU. Any ideas?


----------



## MoodySteve

The Glass Jar Kit has everything you need for the PSU - you only need to buy hardware and the transformer (assuming you're building according to the stock BOM).


----------



## simwells

Quote:


  Originally Posted by *MoodySteve* /img/forum/go_quote.gif 
_The Glass Jar Kit has everything you need for the PSU - you only need to buy hardware and the transformer (assuming you're building according to the stock BOM)._

 

Yeah I wasn't awake when posting this! I meant the transformer, struggling to find sources in the UK.


----------



## adamus

buy an Rcore from ebay, cheapest method i could find in the uk.


----------



## simwells

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_buy an Rcore from ebay, cheapest method i could find in he uk._

 

Just looking now, I'm slightly confused as to which one I'd need though! Any help would be greatly apreciated


----------



## adamus

from memory r80-36


----------



## dean0

Tube-Town Online-Store - Hammond 370FX ha370fx

 Hammond 370FX 77Euro + Shipping is not that expensive.


----------



## simwells

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_from memory r80-36_

 

Thanks for that

  Quote:


  Originally Posted by *dean0* /img/forum/go_quote.gif 
_Tube-Town Online-Store - Hammond 370FX ha370fx

 Hammond 370FX 77Euro + Shipping is not that expensive._

 

Is there any advantage of spending the extra on the Hammond?


----------



## adamus

no


----------



## simwells

Sorry about all the questions, but will this complicate the build when using the glassjar kit?

 My knowledge of transformers and wiring them will have to improve before I build this I know, but on looking at this thread at comments about the R-Cores they kind of give the impression I would have to approach the circuit slightly differently. Or am I just over complicating things?


----------



## adamus

Rcore is slightly more complex as you need to parallel the heater windings. You can do that with a multimeter though.


----------



## simwells

How hot do these actually run?

 Thinking of how I want to do the casework, wondering if I could do a partially acrylic lid.


----------



## adamus

if you have all the tubes well exposed (so reverse mount components, and on the psu board us a socket riser) then you may get away with it.


----------



## bhjazz

I'm looking at the Goldpoint MiniV stepped attenuator for my Bijou. Stereo MiniV (with SMD) or standard MiniV with through-hole? I seem to remember reading pabbi's impression that the through-hole version was a tick better...

 Thanks!


----------



## ujamerstand

This might be a newb question, but does stepped attenuator really offers that much advantage over a pot such as ALPS RK27? is the cost difference truly justified here? Personally, I'd skim on the cost and go with something like this, but I'm not really sure if the lower cost implies lower construction quality. :s

 BTW, Adamus, I remember you posted a heater suppply that had R9 attached to a balanced ground, (one similar to the amphead mod) along with a ground loop breaker after that. (Sorry, can't find the image. But I'm sure you know what I'm taking about 
	

	
	
		
		

		
			





) What is the advantage of such a circuit over the amphead mod's heater supply?


----------



## bhjazz

Quote:


  Originally Posted by *ujamerstand* /img/forum/go_quote.gif 
_does stepped attenuator really offers that much advantage over a pot such as ALPS RK27? is the cost difference truly justified here?_

 

Actually, yes. There has been some discussion earlier in the thread about your very comparison. For me, I'm going to press on and try one. I just want a few impressions about the two currently-available goldpoint units!


----------



## balderon

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_I'm looking at the Goldpoint MiniV stepped attenuator for my Bijou. Stereo MiniV (with SMD) or standard MiniV with through-hole? I seem to remember reading pabbi's impression that the through-hole version was a tick better...

 Thanks!_

 

I decided to use the MiniV/SMD and at times I wish I had built the custom version. On some albums I prefer an listening level that is in between steps. I never turn the volume greater than 1/3rd and I could of tweaked the values for finer control up to mid scale. (I didn't feel like messing with changing the SMD resistors.)

 Another alternative is the DACT CT-2. Justin at headamp.com has a 50K stereo for a good price.


----------



## bhjazz

Thanks, balderon. Interesting notes. The resistor listing (I assume) for the miniV is at http://www.goldpt.com/r_series.html. So for the 24-step listing, the first half of the dB values are:
 off 9 6 5 4 3 2 2 2, ...
 So would you like that list to be closer to 
 off 9 6 5 2 2 2 2 2... ? 

 Or, are you wishing for even finer control in the middle? Maybe 9 7 5 2 1 1 1 1 2 2 2... ?

 Good point. Maybe the custom might allow a bit of fiddling. 

 Thanks!


----------



## Olli1324

Hi all,

 I have just ordered the kit for the Bijou from Glass Jar Audio, and have a couple of questions.

 I have read most of this thread, but some of the information and links are/may be a little outdated.

 What transformer would be suitable for use in the UK?

 What cases are there which are particularly suitable? Any good hifi2000s?

 I want to have the tubes sticking out the top; as far as I am aware, this is simply a matter of mounting the tubes on the back of the pcb so that components face down and tubes stick up? And then the board is lifted from the ground with big spacers?

 Thanks for your help 
 Olli


----------



## adamus

transformers -

 either the rcore mentioned throughout, or order a customer from airlink transformers, they are very cheap. 

 cases - hifi2000 galaxy

 tubes showing - mount tubes on top with components below (amp boards) PS is more difficult. I used a socket saver (like a tube riser) to level the ez81.


----------



## Olli1324

I found the website with the transformers you mentioned, but would you be able to point out the precise one which is suitable? I don't trust myself enough to pick the correct one!

 And also with the case, what width/height/depth would be best? 

 Sorry if these seem like silly questions; it's just that it will be cheaper if I get these things right first time round!

 Thanks


----------



## bhjazz

Welcome Olli! 

 HiFi 2000 Galaxy are available through audiokit.it. Great place to shop. You'll need to decide just how far out you want the tubes to show. 

 Also - when building up the boards, pay close attention when mounting certain components on the back side. Observe all directional needs (diodes, caps, etc). Even one component set up backwards could cause a lot of trouble (or more). 

 If you want to browse this thread or search from a different location, try out Head Fi MegaThreads at Home / Head-Fi Megathreads. At the very least, you can browse all photos in the same place.


 Hey - check out this post count: 1337. Sw33t!


----------



## UKToecutter

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_I found the website with the transformers you mentioned, but would you be able to point out the precise one which is suitable? I don't trust myself enough to pick the correct one!

 And also with the case, what width/height/depth would be best? 

 Sorry if these seem like silly questions; it's just that it will be cheaper if I get these things right first time round!

 Thanks_

 

Olli,

 It's the R80-36


----------



## UKToecutter

BTW,

 I'm going to use the 1GX383 Galaxy Maggiorato GX383 330 x 230 mm for my build


----------



## Olli1324

Thanks for the welcome and tips 
	

	
	
		
		

		
			





 I will place an order for the 1GX383 case tomorrow; it looks great.

 I could not find the r80-36 with my brief search, but i'm going to bed now so I will have a proper look tomorrow.

 Thanks for all the speedy responses!


----------



## UKToecutter

Olli,

 Have a look at Audio Catalog
 I got mine in 9 days from them.


----------



## Parafeed

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_I could not find the r80-36 with my brief search, but i'm going to bed now so I will have a proper look tomorrow._

 

Drop me a PM if you'd like a Hammond 370DAX transformer. I have several new ones spare @ £50 each. (That's what I paid for them.) I don't know how that compares to the cost of the R-Core. Probably not favourably, but factor in the shipping cost if you're only ordering the transformer.......


----------



## balderon

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_So would you like that list to be closer to off 9 6 5 2 2 2 2 2... ? 

 Or, are you wishing for even finer control in the middle? Maybe 9 7 5 2 1 1 1 1 2 2 2... ?_

 

Ideally I would like 9 8 7 6 5 4 3 2 2 2 .... Since I don't want to deal with the SMT resistors I'll probably add a divider circuit ahead of the MiniV/SMD.


----------



## simwells

Quote:


  Originally Posted by *Parafeed* /img/forum/go_quote.gif 
_Drop me a PM if you'd like a Hammond 370DAX transformer. I have several new ones spare @ £50 each. (That's what I paid for them.) I don't know how that compares to the cost of the R-Core. Probably not favourably, but factor in the shipping cost if you're only ordering the transformer......._

 

From eBay an R-Core is pretty much the same place but you have to wait for shipping from the states etc.


----------



## UKToecutter

Quote:


  Originally Posted by *simwells* /img/forum/go_quote.gif 
_From eBay an R-Core is pretty much the same place but you have to wait for shipping from the states etc._

 

Hong Kong I think


----------



## Olli1324

There don't appear to be any r80-36s on eBay at the moment. I'm in no real rush, so thanks for the offer Parfeed, but I reckon I will wait and see if one comes up on the Bay if it will outperform the Hammond.

 Now to place the order for that awesome looking case.


----------



## UKToecutter

Quote:


  Originally Posted by *UKToecutter* /img/forum/go_quote.gif 
_Olli,

 Have a look at Audio Catalog
 I got mine in 9 days from them._

 

Olli

 Did you not see me post about the source for R-Core above?


----------



## Olli1324

Oh sorry, missed that. I'll have a gander at that site now then.


----------



## adamus

I have just received a custom 110va toroid for another project from Airlink transformers. 

 Give them the spec and they will build it. Mine has 5 secondaries including an HV (260v) and it came to £40 delivered. Wouldnt suprise me if it ended up cheaper than the chinese Rcores. Why not drop them an email. I am a convert!


----------



## Olli1324

Mmk, just to confirm, I have to email them to make the order? Like so:

 1. Item number
 R0080-036

 2. Quantity of each item
 1

 3. Name and Shipping address
 Oliver Freeborn
 10 Address
 City
 England

 4. Payment method and related information. e.g.paypal account
 Paypal account (paypal email is paypal@address.org)

 5. Shipping method prefered
 Surface Parcel


----------



## UKToecutter

Yep, 

 That's about it
 He'll send you a paypal invoice with the shipping included.

 I don't know about surface parcel as the method though. I think I selected air.


----------



## Olli1324

Double post!


----------



## Olli1324

OK, thanks for your help. I have emailed him, and shall see what happens 
	

	
	
		
		

		
			





 Also, I have ordered the hifi2000 Galaxy case


----------



## bhjazz

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_Ideally I would like 9 8 7 6 5 4 3 2 2 2 .... Since I don't want to deal with the SMT resistors I'll probably add a divider circuit ahead of the MiniV/SMD._

 

Goldpoint's website has some good examples for doing just that. You might also consider a high gain/low gain switch. Probably less connections that way. Maybe have the regular input be the high gain (with few or no connections) then add a shunt to drop off some power for the low gain.


----------



## pidesd

hi everyone,

 i d like to use the bijou psu to power my darkvoice 336i which draw around 156mA at 200V. is the psu capable of delivering that much current or it would require heavy modifications? 

 if you have other suggestions for a more suitable psu, i m open. a 127V psu for the input stage only could be a nice alternative. here the schematic if it can help:

http://www.flickr.com/photos/85027025@N00/2100832323/

 regards,

 -pierre


----------



## adamus

156ma? thats pretty huge for headphone amp... are you sure?

 See here for another solution. http://www.diyaudio.com/forums/group...roup-buys.html


----------



## dean0

More update's 
 - Rewiring the power/heater wiring with 18awg Silver Plated Teflon wire, the stuff I was using was 22awg.
 - Shielded Input/Output Wire.
 - Replaced coupling/output caps with M-Caps.
 - Goldpin ECC99 Valves.
 I will post more pics/impressions once I have wired it all up.


----------



## Olli1324

Just ordered the transformer (with air shipping).

 Things should start arriving later this week!


----------



## adamus

good stuff. 

 With the bijou 95% of the build is the wiring and casework. take it steady and you'll do a good job.


----------



## ujamerstand

hm... I see that the part list suggests a 100k volume pot, yet I see a lot of people using 50k pots. Even Jeff's kit comes with a 50k velvet blue. Why is this? How does the deviation affect the circuit?


----------



## adamus

doesnt. 50k is fine.


----------



## ujamerstand

Perfect.


----------



## simwells

My R-core transformer has arrived now is there any good resources for learning how to wire it up?

 Also when my glass jar kit actually gets shipped are there any paticular caps that would benefit from an upgrade?


----------



## ujamerstand

When you look at the transformer itself it should have a picture that perfectly describes how to wire it up. Just be aware of the phase, indicated by a dot on the diagram, and make sure you wire up the correct wire with the correct voltage to each voltage input on the PS board. the Cavalli Studio website has plenty more information on it.

 You probably would receive the most benefit by changing C5 and C6; Some people use Big M-caps here. Increasing the values for c1, c3, and c4 would lower the cutoff frequency as well. You can do a search for the values used with the megathread search tool. This tool is useful to see what people like to use in their upgrades too. 

 Have fun with your new toy.


----------



## dBel84

Link to Rcore details in post 1172

 ..dB


----------



## GWorlDofSPACE

Hi guys, 
 I do not want to read true 200 pages. So please I need to know how much is the current draw of bijou whit 6dj8,ECC99 and EZ81 whit regals modes? If its much greater then standard configuration then I should not install a bigger cap after rectifire tube as 47uf? I am using a choke! Maybe 100uf?


----------



## GWorlDofSPACE

Hi guys, 
 I do not want to read true 200 pages. So please I need to know how much is the current draw of bijou whit 6dj8,ECC99 and EZ81 whit regals modes? If its much greater then standard configuration then I should not install a bigger cap after rectifire tube as 47uf? I am using a choke! Maybe 100uf?


----------



## regal

Quote:


  Originally Posted by *GWorlDofSPACE* /img/forum/go_quote.gif 
_Hi guys, 
 I do not want to read true 200 pages. So please I need to know how much is the current draw of bijou whit 6dj8,ECC99 and EZ81 whit regals modes? If its much greater then standard configuration then I should not install a bigger cap after rectifire tube as 47uf? I am using a choke! Maybe 100uf?_

 

No the rectifier tube can't handle that.

 Read the datasheet:

Philips EZ81 (datasheet) | High Fidelity Tubes


----------



## GWorlDofSPACE

Thank you Regal, I checked it. Do you know what is the AC voltage after 47uF capacitor?
 I could check but then I need to unmount my case! 
 I found an electronic choke which according to tests would really clean the psu up.
 The choke is using a 330uf cap as input cap and 330uf as output cap. The instructing is saying the choke needs 15V AC for working perfect.


----------



## simwells

Quote:


  Originally Posted by *ujamerstand* /img/forum/go_quote.gif 
_When you look at the transformer itself it should have a picture that perfectly describes how to wire it up. Just be aware of the phase, indicated by a dot on the diagram, and make sure you wire up the correct wire with the correct voltage to each voltage input on the PS board. the Cavalli Studio website has plenty more information on it.

 You probably would receive the most benefit by changing C5 and C6; Some people use Big M-caps here. Increasing the values for c1, c3, and c4 would lower the cutoff frequency as well. You can do a search for the values used with the megathread search tool. This tool is useful to see what people like to use in their upgrades too. 

 Have fun with your new toy. 
	

	
	
		
		

		
			



_

 

I know this is mostly opinion but would using Elna Silmic for the electrolytic caps and Mundorf M Cap MKP be likely to be enough for the amp section? Would these be overkill for any of the caps or would I majorly benefit from upgrading any of the other specific caps? (I may leave C2 due it not being mentioned as benefiting an upgrade).

 Also I'm waiting a response from glassjar but does anyone know if his kits use the exact values as listed on the parts list?


----------



## adamus

if you are talking output caps i dont think you will find silmics at the right voltage


----------



## ujamerstand

Quote:


  Originally Posted by *simwells* /img/forum/go_quote.gif 
_Also I'm waiting a response from glassjar but does anyone know if his kits use the exact values as listed on the parts list?_

 

You could always email him and ask for the BOM. I remember the 470uF caps in the PS was replaced with a 600+uF one for better ripple suppression.


----------



## simwells

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_if you are talking output caps i dont think you will find silmics at the right voltage_

 

Very good point actually! What would be recommended for C5 then? I see people using M-Caps but it says aluminium Electrolytic?


----------



## ujamerstand

Aluminum Electrolytic caps were used because its not easy getting film caps with large values. Those M-caps costs a hell lot of money! Personally, I'm going to use some rubycon photo flash caps, and bypassed with some russian TF-3s. I also bought a bunch of other caps to experiment with. I guess you'll have to play around until you find the right combo that suits your taste.


----------



## simwells

Quote:


  Originally Posted by *ujamerstand* /img/forum/go_quote.gif 
_Aluminum Electrolytic caps were used because its not easy getting film caps with large values. Those M-caps costs a hell lot of money! Personally, I'm going to use some rubycon photo flash caps, and bypassed with some russian TF-3s. I also bought a bunch of other caps to experiment with. I guess you'll have to play around until you find the right combo that suits your taste. 
	

	
	
		
		

		
		
	


	


_

 

The more I read into this the more lost I get! I now know the BOM follows the original parts list for the amp section so...


 C1 could do with being upgraded to 33u,

 so would something like Sanyo 25SC33M be suited?

SANYO|25SC33M|CAPACITOR, 33UF, 25V | Farnell United Kingdom

 would I actually be benefitting over just going with Panasonic ECA2EHG?

PANASONIC|ECA2EHG330|CAPACITOR, 33UF, 250V | Farnell United Kingdom


 C3 and C4 could do with being upgraded to 220n

 Would Epcos B32652A4104J be suitable?

EPCOS|B32652A4104J|CAPACITOR, 0.1UF, 400V | Farnell United Kingdom


 C5 benefits and upgrade, so going with Rubycon flash caps here?


 C6 go with MCaps? Any other cheaper but virtually as good options?


 Also do any of these specifically generally benefit from bypassing? Seem to see a lot on bypass C5 any recommendations for this?


 Sorry about all the questions! Lack of experience makes it very difficult to decipher opinion from fact and the lack of UK suppliers doesn't really help either.


----------



## ujamerstand

The sanyo cap you listed is not rated at the right voltage, it should be rated for 250V. The panasonic and epcos caps are fine though. Actually, I wouldn't worry too much about the capacitance of these things, since the caps listed in the BOM already pushes the roll off frequency below audible frequency anyways. 

 As for output capacitors, Obbligato from diyhifisupply seems to be a nice and low cost alternative, there're also a bunch of cheap russian PIO caps from Ebay. dsavitsk has a good writeup on output caps if you want to know more about them. I think bypass capacitors are there to "tighten" up the sound, as electrolytic caps aren't as accurate as film caps, PIO caps... etc. Others can correct me if I'm wrong. 

  Quote:


 Sorry about all the questions! Lack of experience makes it very difficult to decipher opinion from fact and the lack of UK suppliers doesn't really help either. 
 

You won't be sorry once you have that thing running.


----------



## nattonrice

There is also an "orgy of capacitors" thread here http://www.head-fi.org/forums/f21/or...thread-284863/

 But the best thing is to ready thru the first 100 pages or so of this thread.
 There were a lot of impressions on different c6's.


----------



## nattonrice

Stupid double post...


----------



## ujamerstand

Okay, if everything goes well, I should be able to stuff a Joshua tree (modded to 50K) into the enclosure I'm looking at, along with the bijou. Its going to be a tight fit, but I think its going to work. Here's the problem. I dont't know which option I should go with right now:
 a) use 270DAX and share the 6.3 amongst the attenuator and the heaters. Keep 6.3 volt for the heater, and regulate the 6.3V to 5V for the attenuator. The problem with this method is that there might not be enough current to drive everything.
 b) use 270DX. it has two filament wirings. 6.3V at 3A and 5V at 2A. But I will be running very close to the filament ratings.
 c) use a separate encapsulated El30 transformer with 270DAX. This method will make sure that I always have enough current to go around. The downside is that the extra transformer will take up more space. I might not have the space to fit a JT in there; who knows, I'll have to play around with the dimensions. 
 d) drop the idea of JT altogether.

 Edit: Actually, it seems that I may have an answer. I might settled down on 270EX. It outputs 275-0-275 on the secondary, with 6.3V @ 4A, and 5V @ 3A on the filaments. This transformer might run cooler, but I'd have to drop 25V off. After calculating the resistance needed for the drop, I've determined that I'll need to change R2 to 77k ohm. I've calculated this from:

 Rt = R1+R2+P1
 = 820000+77000+5000
 = 902000

 Current = Vi / Rt
 = 275 / 902000
 = 0.0003049 A

 Vd = Current * (R2 + P1)
 = 0.0003049 * (77000 + 5000)
 = 25 V

 Is this correct?


----------



## simwells

After further reading I think I'm gonna go with Obligatto Golds for C6 and Rubycon flash for C5, only final thing is would I notice the difference between 400uF and 460uF as the price difference is pretty big!

 Also hopefully the final question for a while! As far as I can tell there's nothing in the kit between the transformer and mains I'm assuming I need a kettle lead connector or similar? Any specific requirements with this?


----------



## ujamerstand

Well, you can calculate this from the article I cited, or use what ferrari did. Thus, with your AKG K701 and a 400uF output cap, the -3dB point is:

 1 / (2 * pi * 62 * 0.0004) = 6.41753803 Hz.

 That's far below the lowest frequency human is able to hear. So just use whatever that's going to cost you the least. Someone should check my calculations though. I'm not a physicist and I've always been bad at math. Somebody please check my calculations for me!

 Also, you might want to use something from this page instead of soldering the leads from the transformer directly to the IEC.


----------



## UKToecutter

My kit arrived this morning (thanks Jeff).
 I've been thinking about using a switch to allow NFB to be switched in and out.

 I envisage there may be an issue with wiring R1, R12 and the NFB pot to a switch and I've thought perhaps a pair of relays (one per channel) might do the trick.

 Has anyone considered this or carried out such a mod?

 Andy


----------



## Olli1324

Toe Cutter; when did you order your kit from Jeff? 

 I ordered mine somewhere around the 22nd of feb but it still hasn't come 
	

	
	
		
		

		
			





 The hifi2000 case and the RCA/IEC socket/power switch have arrived though. I hope it gets here before this weekend cos I'm gonna have access to a nice little electronics work station over the weekend.


----------



## adamus

luck of the draw. my bihou kit got through customs with no inspection / charge. 

 A jisbos kit costing significantly less so stuck in customs and i was charge £12 to pick it up from the post office. 

 pure luck as far as i can gather"


----------



## Olli1324

Hahahaaaaaaa just won some AKG K701s on the 'bay. I'm also gonna try and get a pair of HD650s and compare them using the bijou and keep the one I prefer 
	

	
	
		
		

		
		
	


	




 Ooo winning ebay auctions is such a thrill!

 I guess I will just have to cross my fingers r.e. the bijou kit...


----------



## UKToecutter

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_Toe Cutter; when did you order your kit from Jeff? 

 I ordered mine somewhere around the 22nd of feb but it still hasn't come 
	

	
	
		
		

		
		
	


	




 The hifi2000 case and the RCA/IEC socket/power switch have arrived though. I hope it gets here before this weekend cos I'm gonna have access to a nice little electronics work station over the weekend._

 

Not quite sure when I ordered, but I think Jeff shipped on the 17th. So, a week or so ahead of you.


----------



## ujamerstand

I've just read some old Headwize thread, and found a semi answer for my original question. Apparently, its possible to use 270EX. Also, it seems that my calculations are wrong. However, it wasn't clear what kind of modification was require. A member suggested that perhaps the same values used in 220V operations applies here. But no definitive answer was given on that. Does anyone know what type of modification is required to use a transformer with 275-0-275 secondary windings?

 On a side note, I just want to know, how many of us is working on this project right now? 
	

	
	
		
		

		
		
	


	




 Cheers,


----------



## rolotube

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_Toe Cutter; when did you order your kit from Jeff? 

 I ordered mine somewhere around the 22nd of feb but it still hasn't come 
	

	
	
		
		

		
		
	


	




 The hifi2000 case and the RCA/IEC socket/power switch have arrived though. I hope it gets here before this weekend cos I'm gonna have access to a nice little electronics work station over the weekend._

 

I recently ordered an EHHA kit from Jeff in late January. It turned up yesterday. Bear with him, he comes through with the goods in the end.


----------



## Olli1324

I suppose adamus is right; I just have to hope for the best 
	

	
	
		
		

		
		
	


	




 ujamerstand: Toecutter and myself are doing this, so that is 2...


----------



## nattonrice

Quote:


  Originally Posted by *ujamerstand* /img/forum/go_quote.gif 
_On a side note, I just want to know, how many of us is working on this project right now? 
	

	
	
		
		

		
		
	


	


_

 

I'm thinking up ideas for casing atm.
 I still need to get the parts to populate the power supply.


----------



## theHof

I'm planning on starting up the Bijou, I'm seeing through-out hear a lot of people saying they have their's balanced. What does this mean exactly? Has anyone made this with XLR outs? Is this possible at all?


----------



## adamus

yes but you need 2 bijous in one case. pricey....and massive.


----------



## fishski13

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_yes but you need 2 bijous in one case. pricey....and massive._

 

x2. i miss it from time to time though. crazy holographic 3D Avatar-like sound.


----------



## theHof

That looks like something that would drive some balanced senns quite well 
	

	
	
		
		

		
		
	


	




 yes? Loving the idea of "crazy holographic 3D Avatar-like sound".


----------



## pabbi1

My balanced Bijou is in the sig - it was ~$700 with the TKD attenuators. Sadly, I have too many amps to actually miss it.

 And, it does drive Senn hd6x0 and hd800 VERY well, along with HE-5. Just crazy good with those phones.


----------



## nattonrice

If you stick with a standard bom then a 4 board build will be reasonably priced.
 If you go um, wanky, with caps ect then it will be quite pricey.


----------



## ujamerstand

pabbi: did you turn up the NFB when you were listening to the HE-5? 

 Also, could somebody confirm this: ECC99s were recommended for Regal mod because people were unable to regulate to 250V using 6N6Ps with the mod, is this correct? Thus, modifying the power supply with capacitance multiplier should correct it, is this correct?


----------



## adamus

a lot of people use the regal mod with 6n6p - some have no issues, others do.


----------



## ujamerstand

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_a lot of people use the regal mod with 6n6p - some have no issues, others do._

 

Excellent, I'll perform the capacitence multiplier modifications just to be sure.


----------



## simwells

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_Toe Cutter; when did you order your kit from Jeff? 

 I ordered mine somewhere around the 22nd of feb but it still hasn't come 
	

	
	
		
		

		
		
	


	




 The hifi2000 case and the RCA/IEC socket/power switch have arrived though. I hope it gets here before this weekend cos I'm gonna have access to a nice little electronics work station over the weekend._

 

Yeah I'm in the same position as I ordered mine mid Feb and it got sent saturday, guessing if UKToecutter got his then ours in customs waiting to send us a bill!


----------



## regal

Quote:


  Originally Posted by *adamus* /img/forum/go_quote.gif 
_a lot of people use the regal mod with 6n6p - some have no issues, others do._

 

I think it depends on the quality of your power company, some have minor brownouts that stress the transformer from delivering the required current for the 6n6ps, they do sound better if you can get them to work IMO.


 You can test by checking your power outlet, should maintain at least 115V's with a 1500W heater on and off.


----------



## DemonicAngelz

Does anyone have a wiring diagram for a balanced bijou? I've tried to find one but only found the single ended version. 

 Also does NFB work here? Do you need one pot or two for this balanced NFB set up if applicable. I intend to wire left and right audio volume pot seperately.


----------



## pabbi1

Quote:


  Originally Posted by *ujamerstand* /img/forum/go_quote.gif 
_pabbi: did you turn up the NFB when you were listening to the HE-5?_

 

Nope, no alterations at all, through my balanced Bijou.

  Quote:


  Originally Posted by *DemonicAngelz* /img/forum/go_quote.gif 
_Does anyone have a wiring diagram for a balanced bijou? I've tried to find one but only found the single ended version. 

 Also does NFB work here? Do you need one pot or two for this balanced NFB set up if applicable. I intend to wire left and right audio volume pot seperately._

 

You can either use two stereo pots, or one 4 deck pot. Basically, you need 4 decks in any packaqge. Then look at the Beta22 for the fully balanced wiring diagram.


----------



## Olli1324

Oooo picked up the kit today! 12 quid customs (8 of which is a Royal Mail handling fee - and they are still losing millions!), but at least it is here, and I can handle 12 quid. Gonna start assembling it this weekend.

 Also, my AKG K701s arrived today; I'm currently testing them out on my M3. Initial impressions show that the MS1000s are no slouch. But I won't make any decisions before I have heard the MS1000s, AKGs and HD650s (and maybe the HD600) all on the Bijou.


----------



## simwells

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_Oooo picked up the kit today! 12 quid customs (8 of which is a Royal Mail handling fee - and they are still losing millions!), but at least it is here, and I can handle 12 quid. Gonna start assembling it this weekend.

 Also, my AKG K701s arrived today; I'm currently testing them out on my M3. Initial impressions show that the MS1000s are no slouch. But I won't make any decisions before I have heard the MS1000s, AKGs and HD650s (and maybe the HD600) all on the Bijou._

 

Mine better turn up soon then! Getting impatient the more I hear of others arriving. Want to start and getting building the casing and everything.


----------



## simwells

Just discovered mine was sent to the card not delivery address so will have it forwarded to me very soon! Then just waiting on a few upgrade caps.


----------



## ujamerstand

I've decided to use a joshua tree attenuator for my build. However, joshua tree has a very low output impedance. Hence, I've put together a BOM to modify it to output 50K impedance. I did my calculations using the calculator provided by Jos van Eijndhoven. The resistor values are only approximate. The cost of all the parts including the PCB comes to around 100 USD. Cheaper than a goldpoint or DACT, and it has more MANY more steps. Only downfall is that it takes up a bit of space, but it can be side mounted. Any thoughts?


----------



## pabbi1

Ping luvdunhill - he has a bit better solution with better impedence matching, from what I can tell - but, better hurry. Read some more about it here.


----------



## Olli1324

Mmk, I have populated the boards, and now have a couple of questions.

 For cleaning off all the flux residue stuff, is there likely to be a suitable product floating around the house?

 I am currently looking at the transforming wiring with my dad. I have the r80-36 r-core. He is debating whether we should paralell the two 6.3v/3A secondaries to provide a good dose of current for the toobs. I am using the EZ81, E88CC and 6N6P. Please advise.

 Thank you


----------



## pabbi1

Cleaning flux is best done with 97% alcohol, and a toothbrush. It usually takes 3-4 rounds with 97%, and a more with the more common 'rubbing' alcohol. Not sure anything else around the usual house will work.


----------



## dean0

I use 99% Isopropyl Alcohol, pore some in a small tray put the pcb in to soke for a couple of mins then use tooth brush, and then wash off with distilled water, and leave to dry. PCB always come's up looking great nice shiney joints and no water marks.


----------



## ujamerstand

Quote:


  Originally Posted by *pabbi1* /img/forum/go_quote.gif 
_Ping luvdunhill - he has a bit better solution with better impedence matching, from what I can tell - but, better hurry. Read some more about it here._

 

Thanks pabbi, I've seen that one, its quite interesting! But I'm not sure if I want to go into PGA solutions before I've tried out a relay based solution. On top of that, I've already placed orders for the boards from TPA already. 
	

	
	
		
		

		
			





 Perhaps another time?

 ps. your caps has arrived! Thanks a million!


----------



## Olli1324

What is the current cinsumption of an amplifier board?

 Also, what is the maximum current the PS board should be able to supply befoer the voltage drops below 250V?

 When I connect 1 amplifier board to the PS, the voltage drops from 250V to approx 165V.


----------



## adamus

something is wrong mate. 

 Either mosfet gone in the PS, or a short or wrong component in the amp board,


----------



## Olli1324

Further inspection and poking around by my dad with the multimeter suggests a blown mosfet.

 Gonna order some more tomorrow... 

 This confirms my fear/hatred of mosfets; they are so much more awkward to play with than nice resilient resisters/caps etc


----------



## adamus

typically it takes a short for the mosfet to blow, either a wriing mistake, a solder bridge somewhere, or a slip with a dmm.


----------



## Olli1324

I'll be sure to check all that before powering up with the new mosfets.


----------



## DemonicAngelz

I've decided to build a Bijou after reading this thread from start to end. I'm going to order the kit from GJA soon. But I have a question to start off with, if I'm building a balanced build, is there a recommended transformer to use? I know for the SE version, Hammond 270DAX is recommended but what about balanced? Is there the option of using only one transformer?

 FYI, my mains are 230 Volts at 50 Hertz


----------



## adamus

IF you are going to the lengths of a balanced build, then go with two tranformers. 

 Two of the Rcores would be fine


----------



## pabbi1

My balanced worked quite well with a single Hammond 270HX, so the 370HX should be good for universal voltage, though I did have to use some 10w resistors to bring the b+ down just a bit. It has been too long since I did that to remember exactly, but the recommendation is _somewhere_ in the thread.


----------



## simwells

Got my kit now, only thing I am unsure of is the orientation of the trimpot? I'm sure it's obvious but should the actual ajustment screw line up with the indicated circle or is it the reverse?


----------



## adamus

line it up, but in reality it doesnt matter.


----------



## ujamerstand

I've read in an old post on headwize that recommended 300 series transformers over 200 series transformers for better build quality, less heat and less buzz. Has anyone tried both and reached the same conclusion? Is the 30 dollars difference here justified? btw, a1parts.ca has both 270DAX and 370DAX in stock for Canadians.


----------



## adamus

you do often read that the 200 seeries like to buzz. personally i have the Rcore which is cheap and seems perfect for the application. it also lets you use the fantastic 8416 pq tube.


----------



## ujamerstand

I've considered using the Rcore before. But, well, one of the things I want to do in my particular build is that I want to do the regal mod. Also, I want to have enough current to go around regardless of the tube type I use. This is why I wanted to use the Current multiplier power supply mod. The Rcore seems to need a choke supply, and I am not sure whether that power supply mod will be able to supply as much current as the CMPS. That, coupled with the fact that a) having a choke takes up more space, b) the Rcore listed on vt4c's audio catalog is too fat and wide for the enclosure I have in mind, c) As good as vt4c's customer service is, their shipping is a bit on the expensive side, and takes a long time to arrive; means that I am probably going to stick with Hammond transformers. But thanks for the suggestion, I think I'll go with 370DAX for the assurance of less buzz.


----------



## Olli1324

New mosfets in and all is well in the world again. Better get started on that case soon...


----------



## regal

Quote:


  Originally Posted by *ujamerstand* /img/forum/go_quote.gif 
_I've considered using the Rcore before. But, well, one of the things I want to do in my particular build is that I want to do the regal mod. Also, I want to have enough current to go around regardless of the tube type I use. This is why I wanted to use the Current multiplier power supply mod. The Rcore seems to need a choke supply, and I am not sure whether that power supply mod will be able to supply as much current as the CMPS. That, coupled with the fact that a) having a choke takes up more space, b) the Rcore listed on vt4c's audio catalog is too fat and wide for the enclosure I have in mind, c) As good as vt4c's customer service is, their shipping is a bit on the expensive side, and takes a long time to arrive; means that I am probably going to stick with Hammond transformers. But thanks for the suggestion, I think I'll go with 370DAX for the assurance of less buzz. 
	

	
	
		
		

		
			



_

 



 I considered the R-core so I could use 8416 tubes but found that since they have been discovered they are just as expensive as their equivalent Amperex 6DJ8's. R-cores also have the disadvantage of passing more HF junk from the power company than the Hammond, I think you are making the right decision.


----------



## Olli1324

Is there a minimum distance the rectifier tube should be from the others? Also, does it matter how close the PCBs are? Am I likely to experience any hum/noise if the amp boards are relatively close to the PS board?

 I started drawing/marking up my case for drilling. The tube layout I'm going for is not dissimilar to Balderon's (although I don't think it will trump his for looks).

 I will also be damned if I know what I'm going to do with the transformer; only time will tell if it will fit in the case, let alone not cause hum. Are sticking it on the back (outside of the case) or in a little box with an umbilical chord (although that will look less neat) viable options?


----------



## ujamerstand

Eh, since you have everything running, why don't you just play around with the layout to see which one gives the least amount of hum? 
	

	
	
		
		

		
		
	


	




 Sticking the transformers out the back could work, but then you'll need to take care of all the wires that will need to be connected from the transformer box to the amp. Something like amphenol connector or 8 pole neutrik SpeakON could work? Personally, that's a lot of hassle to deal with, I'd want to avoid that!

 Edit: Actually, instead of putting the transformer in a separate box, you can always mount it on top of the enclosure. No need for an extra box, less cords to deal with, Its a better idea overall I think.


----------



## Olli1324

I was asking because I am doing the case in my grandad's workshop and the electronics stuff at my dad's little electronic 'workshop'. 

 I will continue to mark up the case ( but hold off on the drilling) today, and then tomorrow I should finish the electronics aspect. So after that, I will be able to lay it all out and see if I get any hum/noise.

 Which reminds me.. I better get in a pair of HD650s soon...


----------



## DemonicAngelz

I'm not good at electronics so I'm just going to throw this stupid question out. Does the wattage of resistors matter? I have access to relatively reasonable priced kiwame resistors. Was wondering if I can use them to replace those in the amp.


----------



## Volkum

Quote:


  Originally Posted by *DemonicAngelz* /img/forum/go_quote.gif 
_I'm not good at electronics so I'm just going to throw this stupid question out. Does the wattage of resistors matter? I have access to relatively reasonable priced kiwame resistors. Was wondering if I can use them to replace those in the amp._

 

I wouldn't recommend going under what the project calls for as they could burn out if you run them over spec, but going over on the recommended wattage rating won't hurt (but they may not fit on the board).


----------



## DemonicAngelz

Quote:


  Originally Posted by *Volkum* /img/forum/go_quote.gif 
_I wouldn't recommend going under what the project calls for as they could burn out if you run them over spec, but going over on the recommended wattage rating won't hurt (but they may not fit on the board)._

 

Thats what I thought. Kiwame only comes in 2W and 5W types.. 

 As for fitting on the board, they will not fit flush but should vertically. The bijou board aint really stingy on space given.


----------



## Olli1324

Are you sure the leads will fit? I can't get my spare 1/2 watt resistors to fit through the holes; only the 1/8th watt has leads thin enough to fit.


----------



## adamus

I used a couple of kiwames when i regal modded the bijou, and it was tighter than a....


----------



## bhjazz

Quote:


  Originally Posted by *Volkum* /img/forum/go_quote.gif 
_I wouldn't recommend going under what the project calls for as they could burn out if you run them over spec, but going over on the recommended wattage rating won't hurt (but they may not fit on the board)._

 

Exactly. If your resistor is at or above what is in the schematic, it will do fine. You can throw a lot of cash at resistors that are overspecced, so unless it's a great deal, you probably won't need to. 
 In the range that the Bijou calls for, you can certainly use some of "the good stuff": Vishay, Holco, etc.


----------



## Olli1324

What's that I hear? ...Oh, it's a Bijou!

 Electronics all a-ok.

 I will start drilling the case Monday/Tuesday/whenever I have the afternoon off. 

 And, dammit, I missed a good deal on HD650s this evening..


----------



## ujamerstand

Good deals on HD650s comes every 2 days or so on headfi. 
	

	
	
		
		

		
		
	


	




 Actually, its the first set of headphone I bought on headfi.


----------



## bhjazz

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_What's that I hear? ...Oh, it's a Bijou!

 Electronics all a-ok.

 I will start drilling the case Monday/Tuesday/whenever I have the afternoon off._

 

Fantastic! Wow, you really cruised through that. Have fun!


----------



## metreonfuture

hey, is it really that dangerous to build this amp? how so? (there's a warning on the glass jar site).

 and how much would it cost to do a 10milliamp version of this The Bijou Headphone Amplifier (price range?)


----------



## ujamerstand

In the worst case scenario you can kill yourself, or leave a nasty burn. It is not a safe toy to play with. It contains high voltage and must be treated with respect.

 Regal mod involves changing a couple of resistors. If you have an electronics parts shop in your area, I don't think it should cost over 5 dollars. If not, the resistors can be bought online. Digikey offers $8 dollars shipping. (next day? I think?). If you cannot regulate the power supply to 250V, ECC99 tubes can be found on the net, a new JJ ECC99 tube costs around 15- 17 dollars I think? Look around, they should be easy to find.


----------



## bhjazz

I'm currently looping round the intarweb searching for some C5 caps. I saw that Ferrari had some nice Audyn caps, but I am unsure where to find those in the states. The Rubycons...also not easy to find anywhere other than ebay. I'm kindof jonesin' for those.

 I did run across a few interesting things at audiokit.it. They have JJ TC caps, particularly the TC-309. Specs are 350uf/385V. Electrolytic.
 Also available is the Kendeil polarized electrolytic. There is a 470uf/450V. 

 Any guesses on these? Has anyone used them? 

 Thanks!


----------



## pabbi1

Just shoot me a PM, and I'll send you Rubycons - just tell me how many you need, and pay the requisite $4.95 for priority mail.

 For the record, I still have about 60 of these left.


----------



## Olli1324

Just to add a little update to my progress:

 I did a lot of the case work last week, but had no M4 studding/bolts to raise the boards up nice and high to stick out the case. So, I went with my grandad to the local hardware shop and bought the longest (50mm) M4 bolts there. Alas, they were not long enough! So i have put in an order at RS for a whole load of M4 studding and assorted M4 goodies (at a depressingly lower price than the brink 'n' mortar place...). Hopefully, I should get it Monday, probably Tuesday. Then I will be able to stick in it the case, sort out the holes on the top, wire it up and stick on on my desktop!!!

 Then wait for LCDuino to be released to I can have remote control volume 
	

	
	
		
		

		
			





 Then, probably when placing the Mouser LCDuino order, I will see if I can add any resistors/caps to my order to do the regal mod/other cap upgrades.

 So basically, damn the lack of availabilty of M4!


----------



## bhjazz

PM sent to pabbi1. Hey pabbi1: Thanks for the help. One step closer now!


----------



## amphead

^ Great to hear it!


----------



## vlb

Looking forward to this build, but Im having trouble finding some parts. Can I use Irf820a or irf820 instead of irf820b? Is there any eqvivalents for nte5013t?


----------



## Olli1324

Another update... It has been a while since I made any progress. But I have just done the wiring. I still have to:
 - Fix up proper connection to star ground.
 - Slot the holes in the bottom of the case the the boards can slide around to centre the tubes in the holes in the top of the case properly.
 - Spray paint the top to hide scratches.
 - Move transformer to another box and make up a whacking great cable to link it to the amp (from the limited listening test, I'm pretty sure I have transformer hum).
 - Drill and wire headphone socket (using a temp. solution at the moment; waiting for the postie to bring the proper one).
 - Decide what to do with NFB pot; I'm debating whether to stick it on the front, or just leave it flopping on the premise that I only have to set it once (second option being easier to implement 
	

	
	
		
		

		
		
	


	




).
 - Depending on quality of spray job, decide whether insulating bushings are necessary.

 Wow this goes on and on and on now that I've written it all down...!

 I anticipate it finished and in my bay window on Tuesday. Maybe. Hopefully.


----------



## bhjazz

Quote:


  Originally Posted by *regal* /img/forum/go_quote.gif 
_I completed the 5mA 6922 bias mod to my Bijou.

 Here are the changes:

 EZ81 tube
 JJ ECC99's for V2
 R2 - 487 ohm (1/4W)
 R3 - 30K ohm (2W)
 R5,R6,R7 - 10K ohm (1W)


 You can only use the ECC99+EZ81 combo with this mod, I think the 6N6P's use too much current. The EZ80 probably doesn't have enough power.

 I came up with this mod based on the fact that the 6N6P's use close to 10 mA more current than the ECC99's. This gave the extra power available for the 6922's which were running 1.5 mA's. _

 

So, I continue to rough out the mods and such for the Bijou. In regards to regal's mods, would it do me any good to use EZ81 with the 6N6P tubes that came with the Glass Jar kit? 
 And actually, would the EZ81 even work correctly with the 6N6P? After digging around, I think it would but I should ask first. 

 (I should probably just do the complete regal mod, right? haha)

 Thanks!


 EDIT: Gah! Just found the answer (leave it to me) from runeight: "...I have recommended to JRossel that any Bijou kit that goes out with 6N6Ps should also go out with EZ81s for the rectifiers."

 Good. Onward!


----------



## particleman14

yes I am saving up to buy the bijou kit from glassjar. it looks like he has updated the kit so the regal mod will be that much easier to do!


----------



## bhjazz

Welcome, particleman! I'm not sure if you've read through this thread, but you're getting involved in a really great amp. Have fun!


----------



## ujamerstand

After a few hundred dollars worth of parts and counting, I certainly hope so!


----------



## particleman14

ya, I actually had the pleasure to meet Jeff and hear his Bijou at the bay area head fi after i finish my gamma-2, the bijou will be up next..


----------



## ujamerstand

Oh yeah, particleman, did you get the pcm2707 in the mail?


----------



## particleman14

ya I did.. thanks a bunch for that. is ur gamma 2 100% now? mines almost there..


----------



## ujamerstand

Quote:


  Originally Posted by *particleman14* /img/forum/go_quote.gif 
_ya I did.. thanks a bunch for that. is ur gamma 2 100% now? mines almost there.._

 

Nope, I'm listening to the gamma-1 sections until I make the mouser order for the bijou. There are 3 possible parts that could've went wrong, its around what, 30 dollars worth of parts? -_- Anyways, I guessed I've learned never to finish a project late at night. I'm not going to do that with the bijou; especially with lethal voltage on this one!


----------



## particleman14

have you thought about glassjar audio kits? the price for the parts you get is pretty reasonable..


----------



## ujamerstand

Oh, I'm getting parts from Jeff alright, just handed over a bunch of monies to him. But I want to do some modding to the power supply. This thing here. I don't want to worry about not being able to regulate them to 250V with regal mod. I'm building my build with these mods in mind in the first place. That and the fact I'll need to place a mouser order for replacement gamma-2 parts anyways means that it'd be more economical if I just order everything in one go.

 Edit: runeight recommended changing the 4k7 ohm resistors in the mod to 10k ohm and use the EZ80 rectifier if things were getting too hot. personally I'm getting the beefiest heatsinks to handle the power dissipation. I hope it'll all workout.


----------



## particleman14

ahh i guess I don't have to worry about that since i'm usa power (still reading the thread though). ya making mistakes just gives me an excuse to order a different project along with my 1$ in replacement parts; i always cite shipping costs to justify this habit lol


----------



## ujamerstand

Yeah, I might just get some parts for the BantamDAC pcbs that I have left, the parts just keeps on accumulating. But the mistake I made on my gamma-2 ain't cheap. I think I f'd up the most expensive chips in there...

 Anyways, on the subject of the Bijou, anyone know of a cheap place to get ECC99 tubes? I'm not ready to spend 30 dollars on a pair of tubes just yet.


----------



## bhjazz

370DAX just arrived today. Thanks, Angela Instruments! I had an idea how big it was, but it turned out to be bigger...and heavier. This will change my direction for case size. I very much like the HIFi 2000 cases, and was initially thinking of a short, 12x11 and 3 inch high case, whith parts on top and wiring underneath. Now I see that is just too small for my, uh, style. No, this trafo means I need to step up to big boy cases. Yes, I think a HiFi 2000 "Heavy" case at 17x12 and either 4.72 or 6.5 high will be perfect. I want something to proportionally contain that kind of bulk!

 I've become quite inspired by antique radio designs. Art deco design cues are something I want to include in my case. One unit that seems particularly good for copying would be the EH Scott Full Range High Fidelity Receiver of 1936. 






 I'm going to try to include the simple stair-step look on the front, with fewer tweaky knobs. Somehow. A pilot light would be cool, but LEDs....well, you know I loves me LEDs. MIght be a way to do both, but I'm not sure just yet. I think a few evenings with Google SketchUp might clear it up in my head. At least I don't have to try to accommodate that many tubes. Sheesh.


----------



## Olli1324

Bijou up and running in its case. The transformer is in a nice wooden box I made. Considering it is made out of wooden drawers that are 1 billion years old and curved, it isn't too shabby. The NFB pot is giving a little bit of hum, but I am planning on ditching it anyway, so it's just flopping about. The lid also isn't on. Some bigger hole drills and some sexy aluminium washer type jobs to hide them will need to be made this coming week. 


 Oooh just noticed something. Norah Jones' voice is quite heavily to the left (a little coming from the right cup) and when she puts a little oomph into it, she distorts kind of into the right cup.. Because the amp is not warmed up (been on for 20 mins so far)? James Hetfield's voice is quite recessed in The Unforgiven... But the guitar at the beginning sounds pretty damn 'atmospheric'.


----------



## Olli1324

This is all through AKG K701s. Senn 650s should arrive tomorrow.

 Hmm. I just turned it up really loud, and got some horrendous PHHARRP sound. But I just carefully tried again and it didn't happen.. Odd, eh.


----------



## adamus

not odd..... not good at all!

 I would nto have expensive phones plugged in whilst its doing that.... although the large otput caps do offer some protection.

 first thing to do is swap the tubes and see if the problem follows.


----------



## bhjazz

I'm with adamus, you definitely want to use only throw-away headphones before you completely test out the amp. I'd vote for something small, white, that often comes free with another purchse...

 If you don't immediately find the problem, post some pics and we'll give you a hand with troubleshooting.


----------



## Olli1324

Hmm the PHHARRP sound seems to be quite nicely centred, so perhaps the tubes aren't screwed? Or perhaps just both channels are screwed 
	

	
	
		
		

		
		
	


	




 I'm listening now through my ms1000s and I just turned it all the way up and no PHARRRP (using the volume pot). However, turning NFB to the other side gives some more tasty phharrpness.

 I got it! It sounds like a fog horn. If that is any help...

 I did test it using cheaper earphones and it sounded fine. It also sounds fine (most of the time) through headphones, bar the hum from the poorly executed (on my part, not Mr. Cavalli's) NFB (I am chopping it out soon anyway). But yeah, I'll leave the proper 'phones out until I fix the problems 
	

	
	
		
		

		
		
	


	




 I have no idea what is going on (as may be evident).

 I'll post pics tomorrow when I find a camera.

 (I used too many brackets).


----------



## ujamerstand

Let us know what may have caused it if you do find out what happened. It may help the rest of us out greatly.


----------



## Olli1324

Cool. so this morning I am not getting the loud hum (pharp)by twiddling the volume pot, but I do get it if I turn NFB right up. Am I to assume that this is definitely not normal?

 One thing I do notice is that when the volume is turned right up, it sounds pretty congested, muddled and generally not-very-head-fi. Bass is also lacking. I am sure this amp shouldn't sound like that; my cmoy sounds better! Thus, I believe perhaps there is something, somewhere, wrong.

 My 650s arrived today btw 
	

	
	
		
		

		
		
	


	




 Currently have them plugged into the M3 - not the Bijou yet!

 Anyway, I'm about to go and get the camera, so hopefully you guys will be able to see something I can't!


----------



## Olli1324

Tucked away in there is star ground. It is connected to that stand between some washers. Excuse the crocodile clip holding NFB to ground 
	

	
	
		
		

		
		
	


	








 Tranny in a box.





 General shot.





 The right channel





 The left channel





 All 
	

	
	
		
		

		
		
	


	








 I like this photo. That is what it will vaguely look like when done. This photo is particularly good because you can't see how bad a fit the holes in the lid for the tubes are 
	

	
	
		
		

		
		
	


	




 And there is no headphone socket at that stage...


 If you want more photos, feel free to ask. If you really want me to take the boards out and show the undersides then fine, but bare in mind it took me ages to do the bloody wiring 
	

	
	
		
		

		
		
	


	




 I fiddled about with tubes; no effect on issue.

 To clarify, the issue appears to be general low quality of sound, and loud hum suddenly trips in as the NFB pot is turned up.


----------



## tamu

I would say check the suspicious looking solder joints first.


----------



## Olli1324

Could you specify which ones you think look suspicious? My inexperienced eye can't see many toooo shabby joints.. My dad (years of electronics experience) checked the solder joints when I finished them and he didn't point out anything which needed reflowing which hasn't already been done.


----------



## tamu

I was just saying thats a good place to start checking. There isnt much visible from the photos.


----------



## Olli1324

Yeah.. I dunno what you lot wanna see in the photos. So feel free to ask for a more detailed photo of something you need to see


----------



## bhjazz

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_Yeah.. I dunno what you lot wanna see in the photos. So feel free to ask for a more detailed photo of something you need to see 
	

	
	
		
		

		
		
	


	


_

 

Actually, just looking for suspicious joints, something that was wired in backwards...that sort of thing. I'll take a look myself tonight.


----------



## Olli1324

I just checked it and I cannot see any diodes/caps put in backwards. The only ones I don't trust are D7. I assume that the end with the solid black ring is supposed to line up with the picture on the silkscreen? Other than that... All fine.


----------



## Olli1324

I just played the sound down my mobile to my dad (lol) and he says it could just be instability.. oscillating.. other long words like that.


----------



## adamus

hmmmm. my first though was oscillation, but this is a pretty stable amp. 

 If it is oscillating, then it will much more likely do it when nfb is high - is that the case?


----------



## Olli1324

Yes, precisely. It seems fine when NFB is all the way one way (low), but as I increase NFB and volume increases, I reach a point where this very loud hum kicks in.

 I am also noticing that music definitely sounds odd. Extremely recessed vocals, very muddled and muddied sound. I am listening to some Megadeth and I know from my speakers (DIY ProAc Response 2.5 Clones) that this album should have very strong vocals, thunderous bass and be very cleanly recorded (well, as far as heavy metal goes
	

	
	
		
		

		
		
	


	




) I get none of this from the Bijou, which confuses me. ANd I listened to Katie Melua's Penguins and Cats; it sounded much different from M3/K701, but there was crazy echo going on which actually made teh song sound even more beautiful


----------



## Olli1324

Double trouble

 May as well use this to type something... My dad is suggesting perhaps the 250V is unstable for some reason.. I will check that with a DMM when I get one later this evening.


----------



## adamus

recessed vocals sound to me like you have some wiring wrong somewhere.

 Trace all your wiring, NFB and signal and output, sound a bit like you have a singal and ground mixed somewhere which could lead to instability


----------



## Olli1324

I have just checked over all the wiring, and all seems OK.

 The only thing I am not sure about is the headphone socket. I never checked whether I had it right; I just looked at the tabs and soldered on R/L/G where I though they logically should go.





 In this pic (top down, headphone jack would plug into the bottom of the picture, so to speak), we can see how I have done it. Is it wrong?? I don't think so, but...


----------



## Olli1324

LOL just remembered 'red=ring=right'. There is my first mistake XD! So stupid... I sat there chanting that phrase while wiring it up too!


----------



## tamu

File:Jack plug.png - Wikipedia, the free encyclopedia


----------



## adamus

you only have the left and right wrong though... that wouldnt cause the issue. 

 Check your nfb pot and input pot. 

 labelled pics if poss


----------



## mugdecoffee

Quote:


  Originally Posted by *Olli1324* /img/forum/go_quote.gif 
_Yes, precisely. It seems fine when NFB is all the way one way (low), but as I increase NFB and volume increases, I reach a point where this very loud hum kicks in.

 I am also noticing that music definitely sounds odd. Extremely recessed vocals, very muddled and muddied sound. I am listening to some Megadeth and I know from my speakers (DIY ProAc Response 2.5 Clones) that this album should have very strong vocals, thunderous bass and be very cleanly recorded (well, as far as heavy metal goes
	

	
	
		
		

		
		
	


	




) I get none of this from the Bijou, which confuses me. ANd I listened to Katie Melua's Penguins and Cats; it sounded much different from M3/K701, but there was crazy echo going on which actually made teh song sound even more beautiful 
	

	
	
		
		

		
		
	


	


_

 

One channel of my Bijou for the longest time sounded muddier and slightly quieter than the other. Turned out that I ripped a trace when switching caps and one of the interstage coupling caps was shorted to ground. I think this meant that the output stage was pushing but not pulling (or maybe the other way around). At any rate it might be worth checking the voltages across the coupling caps against the voltage diagram on the site.


----------



## Olli1324

Ok, let's talk inputs.

 I am using shielded cable; the inner core as signal and the shield as ground. Inner core is blue, the shield is obviously thus the pretty silver one.










 That shows the input terminal block. Note that blue is signal, and the silver shield is what I am using for ground.


----------



## adamus

that all looks good, and the joints look ok. 

 How about the star ground - does the continuity check out as it should? 

 If so then then next thing to check is the NFB pot

 Then check out the voltages against the labelled schemeatic on cavalli audio


----------



## Olli1324

NFB:






 The connections on the NFB pot.





 The connections to the board.

 The cool thing is that when I put my finger through that coiled loop, hum increases.


----------



## adamus

you sure that nfb pot is wired right, check the diagram... i cant work it out from the pic but you seem to have too many wires....

 it looks like you have it star grounded?


----------



## Olli1324

It is not star grounded so far as I can see..

 For the NFB pot: I have the Reds going to 1 tab of each gang, browns going going to the middle tab of each gang and teh purples are connected the final tabs of the gang to the middle (brown) tabs. Is this not correct? (and then The red from each gang and the brown from each gang head off to the NFB terminals on the amp boards, as can be shown in my last pic).


----------



## balderon

Definitely check the NFB wiring. Looking at the twisted brown and red wires in your picture, it seems both channels are crosswired. As adamus suggested, study the NFB wiring at the bottom of The Bijou Headphone Amplifier. I would expect only the wires from each channels NFB terminal to be soldered to each "gang" of the NFB pot.


----------



## adamus

shouldnt the purple just be ashort jumper? why the length?


----------



## Olli1324

The length because when I was tacking on wires in anticipation of wiring it up, I didn't realise that they were just jumpers; so I coiled it up and left it so. I just cut them down a bit though; now I can actually see what is going where.










 Those pics should clear up the wiring. Is this wrong?


----------



## balderon

Yes the NFB is wired incorrectly. The red pair (one channel) should be wired to the outer and center (jumpered) posts of one gang and the the brown pair (other channel) should be wired the same way on the second gang.

 When I used the same NFB pot I had significant problems with hum until the I grounded the outer frame of the NFB pot to the star ground.


----------



## adamus

yep, look cross wired to me. ' recessed vocals' gave it away. vocals are typically centred, so out of phase or cross wired cancels them. 

 why is the purple so long? where are the ends going?


----------



## ujamerstand

.


----------



## Olli1324

The purples are still that long for ease of stripping and tying together; I don't have any electronics tools here so I didn't want to make things to hard by cutting them down tiny.

 Anyway, the good news is....

 IT SOUNDS AWESOME!

 Thank you so much Adam and Balderon for spending your evenings helping; I'm very grateful. And slightly embarrassed it was such a small little thing!

 A pretty successful build! Hang on... Still got to sort out the lid...!


----------



## adamus

great stuff. 

 For the lid let me give you a small piece of advice... DO not use a hole saw, they dont play well with the steel. 

 Instead invest in chassis punch fro rapidonline. best £10 you will spend.


----------



## adamus

and one more thing, dont star ground the earth inlet, that should have its own very secure grounding point at nearer the inlet.


----------



## Olli1324

Thanks for the advice


----------



## balderon

This is great news Olli1324! Looking over your pictures you have done a great job on this build. I'm glad your Bijou is alive and well. Congrats and Enjoy!


----------



## Olli1324

Thanks


----------



## vlb

Ivé finaly found all the parts for this build, now I just have to wait 4 weeks for my 370daz. Im going to make this amp wired point to point and build the power suply in a separate box. I have some 20awg silver plated wire (600V) on the shelf, would it work in this amp or will it benefit from a heavier gauge? 

 Ivé also got some 3x0,75 (500V 10A) shielded cable that Im planing to use for heater wiring and PS to amp conection unless sombody tells me its a bad idea.


 Thanks!


----------



## ujamerstand

^^^Whatever works. The stuff you listed are all within specs, so don't stress yourself over them.


----------



## vlb

Im sure it will work, the question is it will affect the SQ. I have experimented a lot with speaker wire and i know that te right cable makes a big difference. But I´m to lazy to try the bijou p2p with different cables. About the shieldning, will the noise it provides to ground affect the sound? At least those wires are simple to change...


----------



## tamu

I received my galaxy today from hifi2000. (They managed to send it to a wrong address).

 Anyway so this is the layout Im going to use. I dont have the cad drawing skills so I used front panel designer.. the two knobs are going to be on the left and right ends, two round vu meters after them, one switch for power and another for crossfeed bypass and finally the jack output.

 I think its going to look very nice


----------



## regal

Quote:


  Originally Posted by *vlb* /img/forum/go_quote.gif 
_Im sure it will work, the question is it will affect the SQ. I have experimented a lot with speaker wire and i know that te right cable makes a big difference. But I´m to lazy to try the bijou p2p with different cables. About the shieldning, will the noise it provides to ground affect the sound? At least those wires are simple to change..._

 

I notice an improvement using 2 conductor shielded mic cable for signal wires, ground the shield on one end only.


----------



## mikey4

Gentlemen,
 I have all the parts to build the Bijou except the 250K dual linear feedback pot. I have not been able to locate anybody that has one. Does anybody have a source for the pot?
 Thanks...Mike


----------



## Olli1324

Are you in England?


----------



## tamu

I also saw the pot on ebay from a source in China/Far east


----------



## funch

1*ALPS 250K 'A' Log Potentiometer Attenuator Stereo New - eBay (item 280489533900 end time May-06-10 09:08:25 PDT)


----------



## ujamerstand

^^^ Are we suppose to use log or linear pot here? Does it matter?


----------



## bhjazz

Quote:


  Originally Posted by *tamu* /img/forum/go_quote.gif 
_I think its going to look very nice
	

	
	
		
		

		
		
	


	


_

 

Me too, tamu! That looks great!

  Quote:


  Originally Posted by *ujamerstand* /img/forum/go_quote.gif 
_^^^ Are we suppose to use log or linear pot here? Does it matter?_

 

The 
 original design calls for a linear, 250kΩ Dual Linear Taper, to be exact.


----------



## fishski13

i haven't chimed in a while. i just wanted to say that i'm really enjoying the Bijou/K702 combo fronted by the y-2.


----------



## ujamerstand

Hey fishski, glad to see you here, really want to thank you for ironing out the capacitance multiplier mod. Those data were very helpful. 
	

	
	
		
		

		
		
	


	




 Just wanted to ask: did you mount your modifications on a separate PCB? or did you simply P2P?


----------



## tamu

2 x 250K OHM Linear Dual Taper Rotary Potentiometers on eBay (end time 19-Apr-10 17:00:04 BST)


----------



## fishski13

Quote:


  Originally Posted by *ujamerstand* /img/forum/go_quote.gif 
_Hey fishski, glad to see you here, really want to thank you for ironing out the capacitance multiplier mod. Those data were very helpful. 
	

	
	
		
		

		
			





 Just wanted to ask: did you mount your modifications on a separate PCB? or did you simply P2P?_

 

thanks. i built the mods P2P on Vectorbord, similar to Chobint's lay-out. please note, Q2 in the pic doesn't have the larger heatsink mounted. i was only testing the mod when the pic was taken and did replace with a larger heatsink.


----------



## dean0

Quote:


  Originally Posted by *mikey4* /img/forum/go_quote.gif 
_Gentlemen,
 I have all the parts to build the Bijou except the 250K dual linear feedback pot. I have not been able to locate anybody that has one. Does anybody have a source for the pot?
 Thanks...Mike_

 

Alps "Blue Beauty" - Hifi Collective


----------



## ujamerstand

Quote:


  Originally Posted by *fishski13* /img/forum/go_quote.gif 
_thanks. i built the mods P2P on Vectorbord, similar to Chobint's lay-out. please note, Q2 in the pic doesn't have the larger heatsink mounted. i was only testing the mod when the pic was taken and did replace with a larger heatsink._

 

Thanks for the pointers, I plan on getting the largest avid heatsink of that series available at mouser. I think it's the 2.5" version? I'm also going to change the 4.7K resistor in there to 10K to spread the heat dissipation. I think it should be fine with plenty of ventilation.


----------



## mikey4

Thanks for the EBAY link. It appears that this part is impossible to obtain in the US.
 ....Mike


----------



## balderon

Hi Mike,

 This is what I used for NFB in my build.

ALPS 250K DUAL LINEAR CONTROL POT! - eBay (item 350269367149 end time Apr-22-10 06:24:43 PDT)


----------



## UKToecutter

Ooh,

 Bit pricey for NFB isn't it?


----------



## UKToecutter

Try....
alphapots

 Good luck


----------



## balderon

Quote:


  Originally Posted by *UKToecutter* /img/forum/go_quote.gif 
_Ooh,

 Bit pricey for NFB isn't it?_

 

No not really. I needed a reasonable quality pot with a shaft length of at least 20mm. The Alps was the only one I found.


----------



## mikey4

Balderon,
 Thanks for the EBAY link. I don't know how I missed that. I just ordered one.
 ....Mike


----------



## nattonrice

I swear this is answered or documented some where but I can't seem to find it in search...

 Does anyone (Alex?) know the exact positions of the four screw holes and the tube socket centers on the amp boards?

 I only want to trust my measurements so far.


----------



## balderon

The best way I know is to measure using the drill templates located on Alex's website. He has both the PS and Amp board layouts. Just make sure to print the images 1:1.


----------



## nattonrice

Hmmm I'll give it a shot tomorrow.
 Thanks!


----------



## bhjazz

I'm looking at the parts for the Regal mods, specifically R2. The original part is an 1/8w resistor. With the changes that occur for these mods (including adding in some 1W resistors) what rating should the Regal mod R2 be? 1W...still an 1/8w? I really didn't see it specced anywhere!

 Thanks!


----------



## balderon

Quote:


  Originally Posted by *bhjazz* /img/forum/go_quote.gif 
_I'm looking at the parts for the Regal mods, specifically R2. The original part is an 1/8w resistor. With the changes that occur for these mods (including adding in some 1W resistors) what rating should the Regal mod R2 be? 1W...still an 1/8w? I really didn't see it specced anywhere!

 Thanks!_

 

I believe the cathode voltage is ~3v@6ma (18mW). 1/8w resistor should be fine.


----------



## rolotube

I've just installed the biggest MCap (330uF/250V) for C5 & it seems to be an improvement over the 200uF Tubecap I've been using for some time. Anyone else tried the big MCap & would it be beneficial to bypass it with a small value HQ film cap. My current thinking is it sounds fantastic without so don't mess with it. I've also read about a so-called "time smear" that can be introduced by paralleling caps in signal circuits. Any thoughts on whether this may be an issue with the Bijou design?

 Thanks.


----------



## balderon

Quote:


  Originally Posted by *rolotube* /img/forum/go_quote.gif 
_I've just installed the biggest MCap (330uF/250V) for C5 & it seems to be an improvement over the 200uF Tubecap I've been using for some time. Anyone else tried the big MCap & would it be beneficial to bypass it with a small value HQ film cap. My current thinking is it sounds fantastic without so don't mess with it. I've also read about a so-called "time smear" that can be introduced by paralleling caps in signal circuits. Any thoughts on whether this may be an issue with the Bijou design?

 Thanks._

 

I see no need to bypass C5. I am using the 330uF MCap and have bypassed with 0.1uF MCap silver/oil. I love the sound and I did not hear any appreciable difference with or without the bypass. I decided to leave it installed because it helps me know where it is so I don't lose it. LOL Ferrari installed the same MCap and he reported the same observations without the bypass cap. fishski13 has installed a smaller MCap and enjoys the sound. I don't know if it was bypassed.


----------



## nattonrice

I have the same 330uf caps here for that reason... glad someone else did the same.
 I have some vcaps lying around that I want to try bypassing with.
 I hope (lol) to get time to actually put this together sometime in the next 2 months.


----------



## tamu

Well all my boards and other parts for the amp cannot be delivered as planes cannot fly in to UK.. Very annoying. I cant imagine how annoyed the people who got stuck overseas feel.


----------



## rolotube

balderon & nattonrice, thanks for comments. I'll continue listening without bypass for the present. I couldn't detect much difference with the 200uF Tubecap bypassed (1uF Jupiter) & I suspect the same would be true for the big MCap.

 0.1uF Supreme S/O's are real nice for C3 & 4.


----------



## mobayrasta

I have a bone stock Bijou, built by dBel84. There are absolutely no mods done, it is the original build. I have noticed quite a few mods have popped up since the original design. Should I consider these. Which one's should I have done? I love the sound and everything works great. Would I get a significant increase in sound quality with any of them?

 Thanks.

 Chris


----------



## mugdecoffee

Quote:


  Originally Posted by *mobayrasta* /img/forum/go_quote.gif 
_I have a bone stock Bijou, built by dBel84. There are absolutely no mods done, it is the original build. I have noticed quite a few mods have popped up since the original design. Should I consider these. Which one's should I have done? I love the sound and everything works great. Would I get a significant increase in sound quality with any of them?

 Thanks.

 Chris_

 

I noticed a big difference after doing Regal's mod. It's dirt cheap to do since you only change resistors. Its just a bit of a pain to pull out resistors of a populated board. I think most of the other mods are to get rid of noise and aren't necessary if your build is working well already.


----------



## mobayrasta

Yes build is totally silent. Don did an amazing job on this amp!


----------



## rolotube

Quote:


  Originally Posted by *mobayrasta* /img/forum/go_quote.gif 
_I have a bone stock Bijou, built by dBel84. There are absolutely no mods done, it is the original build. I have noticed quite a few mods have popped up since the original design. Should I consider these. Which one's should I have done? I love the sound and everything works great. Would I get a significant increase in sound quality with any of them?

 Thanks.

 Chris_

 

I have made all the mods suggested on the official Bijou website (regal, amphead, choke PS, tube rolling, etc) as well as some suggested by Bijou builders on this forum & many of my own. The end result is the best amp I've ever listened to. Whilst these changes have, IMO, been well worthwhile, its has been a lot of work & not come cheaply. No doubt others could also attest to this. But that's the beauty of DIY - you can do as much or as little as you like, whenever you like.

 As for improvements in sound quality, most have resulted in a detectable change or improvement. The sum of these is an amp that is, to my ears, significantly better sounding than the stock build. If you wish to pursue with changes, I'd suggest starting with the simple & cheap ones such as regal's & work your way up to things like expensive & exotic output caps (which can pose mounting problems - don't ask me how I know), choke & other PS mods & expensive resistors.


----------



## fishski13

Quote:


  Originally Posted by *balderon* /img/forum/go_quote.gif 
_I see no need to bypass C5. I am using the 330uF MCap and have bypassed with 0.1uF MCap silver/oil. I love the sound and I did not hear any appreciable difference with or without the bypass. I decided to leave it installed because it helps me know where it is so I don't lose it. LOL Ferrari installed the same MCap and he reported the same observations without the bypass cap. fishski13 has installed a smaller MCap and enjoys the sound. I don't know if it was bypassed._

 

i'm only using 150uF MCaps and bypassed with 0.47uF Sonicaps. the bypass caps could be more or less considered vestigials from an earlier evolutionary age when the output coupling caps were lytics. i probably wouldn't have placed them if using MCaps in the first place.

 i'm also not using any NFB. calculating the corner frequency with my K702 impedance of 62ohms, i get roughly a highish 17Hz. you can argue that bass attenuation isn't an issue, but rather it's the phase distortions that affect frequencies up to the mid bass. i can't say i care. for me, the Bijou gives a funky/chunky bass with guts and nuts that works really well with the K702. i think i've said this before, but the K702/Bijou pairing is very reminiscent of the very engaging Naim Audio sonic sig, but without the bright, dry, harshness that their speakers are known for. 

 i also ripped out my big Electroswitch D9-series attenuator with Dale RN60 resistors and Vishay T2352 nudes. i got sick and tired of trying to turn it - seriously, it was a beast to turn. i replaced it with a 100K PEC pot, shunted with a pair of 100K Vishay T2352. i can't geek-out with a before and after to A/B, but as far i can tell, it sounds just a good.

 i'm planning on bringing my Bijou/B22/y2 to CanJam this year.


----------



## tamu

An update on my progress..

 I havent received the amp parts from GJA yet but have everything else nearly done







 I have also finished building a stepped attenuator for my bijou and I was wondering is it possible to use a stepped attenuator for the NFB as well?
 thanks


----------



## adamus

You *need* to mount those dials on the back, it would look 10x better. 

 as for nfb, dont see why a stepped attenuator wouldnt work, would it make before break, if not you may get some juicy pops.


----------



## tamu

Yeah I will try that too. I thought it would look good with the jack output. Also I will paint the plate in black so it will look much better regardless of having the dials in or out.

 About the nfb; I bought a second hand one off ebay. How would I determine whether its make before break or not?


----------



## adamus

when turning see if you see spikes of resistance.


----------



## vlb

Is it a good idea to use one triode for left and one for right channel in the same tube? Pros cons? 
 I would like to thank you all for this tread, it has helped me a lot.


----------



## adamus

that doesnt happen in the bijou.... all tubes are for one channel. IT does however contain two phases per triode.


----------



## regal

Quote:


  Originally Posted by *vlb* /img/forum/go_quote.gif 
_Is it a good idea to use one triode for left and one for right channel in the same tube? Pros cons? 
 I would like to thank you all for this tread, it has helped me a lot._

 

No but the Bijou has different phases in the same tube so the same concern is somewhat revalent. This has been discussed and there is probably little loss in SQ doing this, the # I remember is 60dB stereo separation in a single tube. No one could prove that we should hear a difference between 60db and 100 db. So for budget it is fine, for all out no compromises don't do it. With the bijou you would have even less a problem because any cross-talk is just going to cancel. Sorry to take the thread off topic.


----------



## TimJo

Quote:


  Originally Posted by *vlb* /img/forum/go_quote.gif 
_Is it a good idea to use one triode for left and one for right channel in the same tube? Pros cons? 
 I would like to thank you all for this tread, it has helped me a lot._

 

I asked this question last year, and here is what Alex said...

  Quote:


  Originally Posted by *TimJo* /img/forum/go_quote.gif 
_Alex, I was wondering if you would mind talking about the pros and cons of using a dual triode as a 'stereo' two channel tube (ala CTH) versus using it as a 'two-stage' tube with one tube per channel (ala Bijou and SOHA II)?

 After building the CTH, I am impressed with the sound quality with both channels of the input stage being shared by a single tube. Is there such a thing as crosstalk within a dual triode?

 I bring this up here because I am contemplating doing the Bijou as a PTP build, and was considering a topology where one tube would handle both channels of the input stage, and one tube would handle the job of phase splitting.

 Any thoughts on this notion, or should I just stick to an equivalent topology of your single channel boards?

 Edit: Just to clarify my thoughts a bit, I got to thinking about this with the idea that you could roll input tubes (like on the CTH) independently of the phase splitter tube. I began to wonder if there could be an interesting level of control and 'boutique' tweaking by dividing the two tasks into separate tubes..._

 

 Quote:


  Originally Posted by *runeight* /img/forum/go_quote.gif 
_Interesting you should ask this. My proto PTP Bijou does exactly what you want to do. The input stages are in one tube and the phase splitters in another. I don't think this generates any significant crosstalk and is a much easier way to do the PTP._


----------



## particleman14

Hey all, i am getting ready to take a crack at a Bijou build.  after reading through tons of text, I had just a couple questions regarding mods and tweaks to the bijou. 
  I plan on getting the glassjar kit. however , I see some guys using fairly large poly caps on the amp boards.  i am just wondering if there is a big difference between those caps and caps i would receive in the glassjar kit. is it worth it to try out some "boutique" caps? any recommendations?


----------



## adamus

film caps are better for the outputs, but you have spend ALOT to get them big enough.


----------



## regal

Actually if you are using a headphone with an impedance of 300 ohms or more I had a huge improvement over the electrolytics by using 100uF ASC Oil Motor Run capacitors.   They sound great,  get decent reviews by some of the cap experts but you need a big chassis and cap ring holders. They were the best mod I did on my Bijou.  You theoretically add a little phase distortion below 50hz or so but it is well worth it in the improvement of sound.    Best thing is they only cost $15 bucks or so a piece.    For lower ohm phones you could put 3 or 4 of them in paralell per channel,   to my ears they actually sound better than most of the costlier film caps available in these sizes.  One caution is I did this on a NFB delete Bijou since it was intended for high impedance phones only,  I think the NFB would require larger caps since the output impedance drops,   but build a SOHA II or EHHA for low ohm phones anyway.
  Quote: 





adamus said:


> film caps are better for the outputs, but you have spend ALOT to get them big enough.


----------



## rolotube

I agree with adamus & regal re improvements brought by using large film caps.  I too am running high impedance phones (650's) & they work superbly with 330uF MCaps which, whilst providing better sound than the stock electros, come at high cost, both in terms of $'s & space required to mount them (they are BIG).  An alternative may be to use the stock electro but with a high quality bypass film cap.  There are quite a few previous posts on this subject.


----------



## dean0

Quote: 





regal said:


> Actually if you are using a headphone with an impedance of 300 ohms or more I had a huge improvement over the electrolytics by using 100uF ASC Oil Motor Run capacitors.   They sound great,  get decent reviews by some of the cap experts but you need a big chassis and cap ring holders. They were the best mod I did on my Bijou.  You theoretically add a little phase distortion below 50hz or so but it is well worth it in the improvement of sound.    Best thing is they only cost $15 bucks or so a piece.    For lower ohm phones you could put 3 or 4 of them in paralell per channel,   to my ears they actually sound better than most of the costlier film caps available in these sizes.  One caution is I did this on a NFB delete Bijou since it was intended for high impedance phones only,  I think the NFB would require larger caps since the output impedance drops,   but build a SOHA II or EHHA for low ohm phones anyway.


 
   
  Sounds interesting, have you got a source for the caps? By using these caps in C5 would I still need the bypass cap in C6?
  Thanks


----------



## adamus

whilst not necessary, you may still want to play with a bypass.
   
  With 300ohm phones, as regal says you can easily get away with 100uf. Drakvoice amps use 30uf film outputs.


----------



## particleman14

ya  been doing some more reading..my problem is I am debating whether to just use my high-z headphones.  or incorporate big enough caps to accommodate my k701..
  I would prefer no nfb, but maybe I'll just experiment with it.  but building an ehha or soha for low z phones seems like another fun project too!  So i am thinking maybe 2 of those motor run caps would be a reasonable mod for not too much extra $.   
  should I grab 2 of these?  http://cgi.ebay.com/New-100UF-100-UF-RUN-OIL-CAPACITORS-CAPACITOR-370V-/380229945477?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item5887788885
   
  also any other recommendations for caps for the other positions? or should i just worry about output caps?  about to empty my wallet for the parts on this build


----------



## adamus

no harm in trying!
   
  I didnt like lowZ phones with the bijou, Purely personal taste but the magic with phones such as the hd650 or the high z Beyers just seemed to go when i tried grados and akg k701. To be honest i was pretty repulsed by the grado bijou combo! However, it is my amp of choice with the senns, really nice sound.


----------



## ujamerstand

Increasing cap values in other position will help with frequency roll off too. But if you decide that you will be mainly driving high impedance cans, then I agree with others, you don't have to spend money on large value caps.

 Quote:


huskydawg9 said:


> Quote:
> 
> 
> Originally Posted by *runeight* /img/forum/go_quote.gif
> ...


----------



## regal

Those look like ASC's,  they are getting harder to find in 100uF that looks like a good deal to me.  Remember they are big.
  
  Quote: 





particleman14 said:


> ya  been doing some more reading..my problem is I am debating whether to just use my high-z headphones.  or incorporate big enough caps to accommodate my k701..
> I would prefer no nfb, but maybe I'll just experiment with it.  but building an ehha or soha for low z phones seems like another fun project too!  So i am thinking maybe 2 of those motor run caps would be a reasonable mod for not too much extra $.
> should I grab 2 of these?  http://cgi.ebay.com/New-100UF-100-UF-RUN-OIL-CAPACITORS-CAPACITOR-370V-/380229945477?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item5887788885
> 
> also any other recommendations for caps for the other positions? or should i just worry about output caps?  about to empty my wallet for the parts on this build


----------



## tamu

its Alive!


----------



## ujamerstand

Cool! Congratulations! I'm surprised you didn't go with a choke supply with that transformer though. Any problems with hum?


----------



## tamu

Havent listened yet. Im gonna leave it for a while as says in the instructions.
   
  Still thinking about painting the front plate in black
   
  what do you guys thk?


----------



## ujamerstand

Nah, I like the contrast that brings to the whole setup once you case it up.  Perhaps get some black knobs to suit! Like these. Actually, look at this. *drool*


----------



## balderon

Congrats on your new build! Are the tube completely enclosed or do you need to cut holes in the top? I would say a black front panel would blend nicely with the headphone jack and meters.


----------



## tamu

Thanks guys.
   
  The black knobs are very nice indeed.. and the black panel is just porn!
   
  listening to the amp now and its very nice airy and controlled. just having some problems with the meters.
   
  balderon i have to cut the top. need to get measurements first.. it is creating heaps of heat and i dont thk tubes in the enclosure is a good idea..
   
  also im getting a slight buzz in both channels when no music is playing and the volume is at max. its not doing it when its not connected to anythg so i thk its a earthing problem somewhere. any ideas anyone?


----------



## adamus

if nothing it connected then it will buzz. short intput to input ground and then see if it buzzes.


----------



## adamus

Tamu, looking good mate.
   
  I would be seriously tempted to get a front panel done by schaeffer  AG, you could make it look superb. pricey though...


----------



## balderon

Quote: 





tamu said:


> Thanks guys.
> 
> The black knobs are very nice indeed.. and the black panel is just porn!
> 
> ...


 
   
  I had the same problem with a slight buzz. I ensured the NFB and volume pots had a solid connection to earth ground. Secondly I had separated earth and signal grounds. The NFB and the volume pot was mounted on the faceplate, thus directly to the metal enclosure, and the ground path from the IEC connector (= earth ground) was also connected to the chassis directly... I had a ground loop problem which resulted in undesired noise or hum. The simplest solution was to use a ground loop breaker (which could be implemented one of many ways). I used a 10 ohm 1W wirewound resistor in parallel with a 0.1uF 250VAC capacitor rated for across-the-line use. I connected earth ground to signal ground through this RC network.


----------



## tamu

I will do a proper earthing when Im on the rewiring.. Its a bit messy inside.
   
  I need to visit the hardware store for some serrated washers. Ive got the Iec connected to chasis plus the star ground. maybe seperating them should solve it. If not Ill try balderons idea.
   
  The front panel by custom order sounds great. maybe Ill get it done in the future.
   
  So Ive been listening for couple of hours and now the soundstage is a bit closer. Still very nice though. Im sure another +100 hours and it will get even better.
   
  is there a limit for the NFB? How much should I turn it for hd600s? I guess it will be ok to have it at max and play with volume?


----------



## adamus

I use no NFB with senns.
   
  Now this is subjective, but i find no NFB = big soundstage + 3d presentation,  Lots of NFB = tight bass, reduced soundstage


----------



## tamu

Himm I might try removing the nfb and see but I have lower impedence hps so its not ideal.. But I agree with the soundstage. When I turn the pot to its max, soundstage is wider but when I turn it to half way it becomes less.
   
  Anyway I replaced the input valves with the siemens goldpins that I had and the mushyness is gone. Much much better now. Maybe I should have waited a while before doing so but it was dark and kind of muffled before..
   
  So far Im loving the amp.!


----------



## dean0

Iam trying to source some 100uF ASC Oil Motor Run capacitors, only ones I found don't deliver to UK. Any links would be much appreciated.
  Thanks


----------



## balderon

Quote: 





> Originally Posted by *tamu* /img/forum/go_quote.gif
> 
> I need to visit the hardware store for some serrated washers. Ive got the Iec connected to chasis plus the star ground. maybe seperating them should solve it. If not Ill try balderons idea.


 

 Separating earth and chassis ground will probably create even more noise. I eliminated the last of the noise by connecting the frame of my NFB and volume pots to star ground.


----------



## tamu

Himm I will try connecting the nfb pot directly to the ground (its body) with a jumper wire and see if it makes any difference.. When listening there is no noise coming anyway. I think its as adamus says..
   
  Thanks for the help guys.


----------



## dean0

Still no luck finding ASC 100uf caps to deliver to UK, any chance you guys have a couple lying around?


----------



## pabbi1

Well, I have 1. The ASC is 100uf, 370v. I also have two (not ASC) 370v 45uf, 1 47uf 500v Obblifgato, and 4 Aerovox 1500uf 350v.
   
  Any of that help?


----------



## dean0

thanks Pabbi, is the ASC the same as this one http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=380229945477&ssPageName=STRK:MEWAX:IT
  those are the ones im after, but they don't ship to UK


----------



## tamu

I cant remember the website but there was a company in states that would accept your parcels and forward it to you.. Very usefull in such times indeed..


----------



## tamu

http://myus2.myus.com/default.aspx
   
  There it is. I have no idea about prices but the idea is great!


----------



## dean0

thanks for the link, but I would much rather pay a fellow headfi member who is willing to purchase the caps and send to me.


----------



## vlb

Seems like I have more parts than I need. Would there be any benefits using one PS per channel? I should be able to push the tubes workingpoint beyoond regals mod?


----------



## adamus

i think you would have a lot of difficulties hearing the difference.


----------



## dean0

Still searching for 100uf motor run capacitors.
  Would these be suitable;
  http://cgi.ebay.co.uk/2-Very-low-ESR-long-life-high-voltage-film-capacitors-/260592043151?cmd=ViewItem&pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item3cac7f048f
  http://cgi.ebay.co.uk/MBGV-100uF-1000V-Paper-PIO-Capacitor-USED-/150442694490?cmd=ViewItem&pt=Vintage_Electronics_R2&hash=item230715575a
   
  Not motor-run but film
  Thanks


----------



## wwmhf

Here are the motor-run capacitors:
   
  http://cgi.ebay.com/New-100UF-100-UF-RUN-OIL-CAPACITORS-CAPACITOR-370V-/380236184432?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item5887d7bb70
   
  I am not sure the shipping to UK is free or not.


----------



## dean0

thanks , but he does not ship to UK.


----------



## regal

I wouldn't get humg up on them having to be ASC.  Just about any motor run 100uf oil cap should do.  I think ASC just got good press because they are the most readily available in the USA.  Also surplus sales of nevada has a nice 150uf oil motor run cap,  but don't know if they ship to the UK.
  
  Quote: 





dean0 said:


> thanks , but he does not ship to UK.


----------



## particleman14

Hey guys, so I'm looking to fill in my bijou with some good caps.  I have been looking at those oil run caps, but I just have one question.  if i parallel to say 300uf, I get a corner frequency of about 8.5 hz with my 62 ohm k701.  Do you think 300uf value will be adequate for lower end response?  I know you're not supposed to hear 8.5 hz but that's -3db corner freq,  I am just wondering if I will be missing any lower end by not using a higher value.  Btw I intend to use my 62ohm k701 and my 600ohm dt990s with this amp.  almost done buying all the parts for this baby..boutique caps are expensive!!


----------



## nikongod

Quote: 





particleman14 said:


> Hey guys, so I'm looking to fill in my bijou with some good caps.  I have been looking at those oil run caps, but I just have one question.  if i parallel to say 300uf, I get a corner frequency of about 8.5 hz with my 62 ohm k701.  Do you think 300uf value will be adequate for lower end response?  I know you're not supposed to hear 8.5 hz but that's -3db corner freq,  I am just wondering if I will be missing any lower end by not using a higher value.  Btw I intend to use my 62ohm k701 and my 600ohm dt990s with this amp.  almost done buying all the parts for this baby..boutique caps are expensive!!


 

 Why not experiment with cheap electrolytic caps to determine what value you need? try 100uf, 220, 330 etc. A bunch of caps should not be prohibitively expensive and with care they can be reused in other projects elsewhere.


----------



## particleman14

well I was hoping to be able to omit C6 bypass cap, but I would probably have to buy one if I used electros for c5.  I am looking to spend my $ on film caps for c5, was just wondering if 300uf would cut it for my headphones.  I think I'll go ahead and order the oils runs for now  as 13 dollars a pop is fairly cheap for 100uf.
   
  also can someone please clarify ampheads ps mod?  Should I go ahead and just do it even though I'm starting from scratch?  am kind of undecided if I should do this mod, as I intend to do regal, choke ps ,and no nfb.  Would amphead's mod be of any benefit?


----------



## xxbaker

Quote: 





particleman14 said:


> well I was hoping to be able to omit C6 bypass cap, but I would probably have to buy one if I used electros for c5.  I am looking to spend my $ on film caps for c5, was just wondering if 300uf would cut it for my headphones.  I think I'll go ahead and order the oils runs for now  as 13 dollars a pop is fairly cheap for 100uf.
> 
> also can someone please clarify ampheads ps mod?  Should I go ahead and just do it even though I'm starting from scratch?  am kind of undecided if I should do this mod, as I intend to do regal, choke ps ,and no nfb.  Would amphead's mod be of any benefit?


 

 nikon meant buy some different values and see at what value the bass becomes noticeably different to you and at what point it's worth it.  Since electros are very cheap you can grab these and test to figure out what value is the best compromise for you, then spend the $$$ on oil.  With that said, 300uf should be plenty for your K701


----------



## particleman14

indded, I was just trying to save my as much $ as I can. and i figure if the 300uf isnt adequate I can buy  additional oil caps.  for 6 100uf caps its about 80 dollars, vs 2x 430uf rubicon photoflash for 40.   I would prefer to spend the extra money on a quality potentiometer instead of additional caps.  its just my wallet is getting thin.  if i want to test caps it will have to be at a later stage because if I buy both now i wont have enough to get the additional parts to make a working bijou. ahh choices choices  Will hopefully get some build pics going here soon.


----------



## regal

I would build a CTH or SOHAII for the AKGs,  for the DT's delete the NFB and use the oil caps on the Bijou  No compomises that way..


----------



## particleman14

I actually bought a soha II board as well so I guess I will configure the bijou for high-z phones.  gives me an excuse to get some hd600s  just ordered almost all my parts; can't wait to build these amps.


----------



## vlb

Iv´e found some nos tessla and tungsram ez81 pretty cheap. Would there be any benefits them instead of new JJ or EH?
   
  Thanks!


----------



## particleman14

here are some pics I just started populating; waiting for my partsconnexion order to add the caps and stuff.    still trying to figure out what I'm going to use to case this.


----------



## moodyrn

I recently bought the balanced version originally built by pabbi. I replaced the two stereo potentiometers with a balanced stepped attenuator(which is working out great). The nfb pot wasn't originally installed. I would like to install it so it could better match my low z cans. I'm trying to decide what pots I could use. I would like to limit it to one pot but I can't find a 4 pole 250k pot. Could I use a balanced 250k stepped attenuator?


----------



## MoodySteve

Sure - you could even use a 4-gang switch with only a few positions, if you knew what value sounded good with your low Z cans.


----------



## moodyrn

Cool, how do you wire it. I'm a little confused by the diagram on the website.


----------



## moodyrn

nevermind, i just figured it out.


----------



## pabbi1

Ok, I am curious - all figured out - and, if so, how does it sound with the HE-5?
   
  Sorry, with the forum change I can't post from work, which really cuts down when I can...


----------



## moodyrn

Right now I'm only able to get low to medium volume out of the HE-5s. When I crank the volume up, it distorts. The nfb pot suppose to solve that problem(from what I've read). I have to wait about 10 days before I receive my pot to really test it out. But the sound I'm getting at the lower volumes is outstanding. I did a mod to reduce the sibilance on them, but with this amp, I was able to undo the mod. The sound is clean, transparent, and lush. I'm really looking forward to installing the nfb pot. This amp reminds me of what they sounded like out of a WA22 I listened to at a meet recently. It was on that amp when I noticed that I didn't need to mod them to reduce the sibilance. So I'm please that this amp matches the HE-5s sonically.


----------



## moodyrn

Pabbi 1 I have to say you did a great job on this amp. I think it's still the only balanced bijou that's out there. This amp is completely silent, even with my low impedance cans. That's a great feat for an OTL amp. One day I may recase it to show off the tubes outside the amp(the glow of 10 tubes at night with the top off is a wonderful sight), but I'm really happy with it. It makes my sextetts sound unlike any sextett I've ever listened to.


----------



## particleman14

hey guys just finished populating my bijou psu and had a quick question.  Do I need the 100k resistor in order to test the power supply? or can I just plug in my dmm and configure the voltage?    I don't have a 100k 1 watt resistor on hand so just wanted to see if I can get by without it. could I string some resistors together? does it have to be 100k?  if so its another order from mouser!


----------



## mugdecoffee

Quote: 





particleman14 said:


> hey guys just finished populating my bijou psu and had a quick question.  Do I need the 100k resistor in order to test the power supply? or can I just plug in my dmm and configure the voltage?    I don't have a 100k 1 watt resistor on hand so just wanted to see if I can get by without it. could I string some resistors together? does it have to be 100k?  if so its another order from mouser!


 

 You could string together 4 25k 1/4 watt  resistors in series which would be much easier to find in a parts box.


----------



## SBoy

Has anybody here tried pairing HE-5 or HE-5LE with bijou??
   
  I heard HE5/5LE is pretty power hungry. =)
   
  Sam.


----------



## pabbi1

I heard it with a balanced Bijou, which had plenty of power for the HE-5, Moodyrn has the unit now, and I know momomo was using it with his HE-5. No idea about SE, unfortunately.
   
  Oh, and it sounded really good BTW.


----------



## SBoy

Great! that was the reply i was hoping for =)


----------



## vlb

If someone is looking för big filmcaps in uk...
  http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260611560663&ssPageName=STRK:MEWNX:IT


----------



## vlb

A lite preview of my build.
  http://img689.imageshack.us/img689/5168/20100616838.jpg


----------



## nattonrice

Woah snap is that dual mono?
  Looks very slick!


----------



## IloveHP

Hello! I'm new here, from SE Asia.
   
  I have a chance to try out the Bijou amp build by my friend and its certainly blow my MKIII away.
   
  I have scrapped enough components to build the Bijou but to keep cost low, I decided to build a Point-to-Point wiring version of it.
   
  I was wondering what is the correct rating of the 10K pot used to adjust voltage on the Power Supply section, I have a number of 10K but they are all rated at .5W to 1W with a max AC rating of 100V. Is it safe to use these particulars batch of Pot?
   
  BTW, if you guy need help getting any components from Singapore, I can help out.


----------



## vlb

Yes it´s going to be a dual mono. I haven´t finished the second PS yet so im using it as a "standard" bijou. I think the second PS will make a big difference, I cant get more than 242V nice dc from my PS with regals mods.


----------



## gabriel-dan

Hi everyone,
  I bought a R-core R80-36 for a Bijou I'm building. The problem is I'm getting 6.99v for the heater. Is that voltage too high? I was thinking on adding resistors to drop the voltage a bit. Has anyone using R-core R80-36 experienced the same high volts for the heater? What wattage resistor should I use?
   
  One more thing, looking at the wiring diagram from the bijou site, the power supply PCB terminal block shows 6.3v x2. Please correct me if I am wrong, is that two times 6.3v with respect to ground(chassis) or across the terminal?
  Thanks in advance


----------



## adamus

i found the heater v a bit hot too.
   
  to work out the resistor value and wattage, you need to use ohms law
   
  Vdrop = I heater X Rdrop
  Vdrop = 0.6V
  Iheater = sum of heater currents
  work out R drop from there.
   
  Power = V I
   
  leave a margin of at least 50% for the resistor wattage, some prefer more.
   
  the two 6.3v are 6.3v wth respect to eachother


----------



## gabriel-dan

Thanks for the info Adamus, much appreciated.


----------



## Ant1Xr1st

Some updates of my DC coupled Bijou project. I think it's going to be a final version. The only one thing i want to try is to use a parallel 6N6P _(ECC99)_ I haven't find any notice about it in this huge thread.


----------



## ujamerstand

Interesting. So you added a dual power supply and separated the sections to accommodate the servo. I'm not an engineer, so I could be wrong, but wouldn't the difference in ground reference be a problem? And I see you eliminated the global feedback loop, any reason to the change? I hope to see more explanation to the changes applied. 
   
  Edit: Actually, never mind about the ground reference problem. I forgot that the phase splitter cathode returns to output instead of ground.


----------



## Ant1Xr1st

*ujamerstand*, the gain & phase splitter part is't dc coupled with buffer stage. there will be no problems with ground. we just will need a higher voltage caps (C107)
  i just don't use the feedback because of my high impedance headphones, but i think it should work


----------



## ujamerstand

Ah, right, you got 0.1u caps in there. Plus if anyone want global feedback in there for low-z cans should be easy enough.


----------



## pabbi1

Quote: 





ant1xr1st said:


> Some updates of my DC coupled Bijou project. I think it's going to be a final version. The only one thing i want to try is to use a parallel 6N6P _(ECC99)_ I haven't find any notice about it in this huge thread.


 


  
  I used 6n1p / 6n6p in my Bijou (no idea who has it now), but I did find it took several hundred hours to burn the static out of the tubes. I'd suggest 6n23-ev instead, as those should be almost as cheap for you there, and you _can_ use 6h30p... have a look at CA tweaks page .


----------



## clifwst

New member here, 
   
  I ordered a kit from Glass Jar Audio this week and collecting parts for an enclosure.
   
  I have a piece of aluminum diamond plate I want to use for a top plate.
   
  I have a question, can the amphead heater mod and cap multiplier mod be done on the same power section?
   
  If so would you remove the R9, instead of changing it's value like it shows here.
   
  Thanks.


----------



## TimJo

Welcome to Head-Fi and the wonderful world of Cavalli amps. 
	

	
	
		
		

		
			




   
  Yes I believe that would be the case since the goal of amphead's mod was to isolate the heater wiring from B+, but maybe someone more experienced than me can confirm as well...
  
  Quote: 





clifwst said:


> New member here,
> 
> I ordered a kit from Glass Jar Audio this week and collecting parts for an enclosure.
> 
> ...


----------



## ujamerstand

Hey, finally somebody else wants to combine the capacitance multiplier mod with amphead mod. Check out this post by adamus though, it elevates the CT and put it away from the heater cathode limit.


----------



## clifwst

In his diagram, he has two 64k resisters, and two 10u caps, shouldn't the set off one leg of the heater power be removed, because the set off the two 100 resisters replaces them?
   
  I can see what he is trying to do with the regal mod, however the way the diagram is posted it is a bit confusing.Amphead's mod removed them, however in the diagram then seem to return.
   
  I guess my new question becomes, can the adamus mod of amphead's mod be done with the capacitance multiplier mod?
   
  What would it look like the following diagram?
   
   

   
  Or would the R9 resister need to be a 348k resister as per adamus original mod?


----------



## TimJo

I don't have a lot of time right now, so I can't look at the values on your revised schematic, but as far as my understanding goes, yes you can add the adamus mod as well.
   
  The cap multiplier is really only effecting the way B+ is being produced.
   
  The goal of adamus' mod was to elevate the ac signal the heaters are seeing with a fixed dc offset. The reason for this is to ensure that the cathode to heater differential of the chosen tubes are not exceeded. The values for the max voltage differential can be found on the tube data sheets.
  
  Quote: 





clifwst said:


> In his diagram, he has two 64k resisters, and two 10u caps, shouldn't the set off one leg of the heater power be removed, because the set off the two 100 resisters replaces them?
> 
> I can see what he is trying to do with the regal mod, however the way the diagram is posted it is a bit confusing.Amphead's mod removed them, however in the diagram then seem to return.
> 
> ...


----------



## adamus

My original sketch up was indeed a little rushed, and the revised diagram above is correct (cap and resistor layout).
   
  question is though, can that be done on the boards... probably but i havent looked yet. It may require a trace to be cut.
   
  All we are doing is elevating the heater supply to 40ish voltages. 30 / 40 / 50 iit doesnt really matter. The 390k and 64k form a divider and having the high values reduced  current draw to something negligable.
   
  .... juts needs someone to test.


----------



## vlb

I just have to recommend the bijou as a preamp.. It´s sounds wonderfull together with my audio research d250 mkII (2*250w tube). Since the input impedance of a power amp is way higher than the headphones you can get away with a small filmcap for the output. Right now Im using 120uf filmcaps (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260627749981) for both headphone and line output, but Im thinking about trying some fancy small filmcaps for line output.
  How do I calculate the -3db freq? I know I have read it somewhere in this thread but I can´t find it.    
   
  Thanks


----------



## nattonrice

Corner frequency is  f_c  = 1 / 2*pi*R*C


----------



## clifwst

Thanks adamus, I am not real good at merging circuits with out smoke and flashes yet....  I am interested in building the kit with both mods and Regal's mod.  I plan on socketing R2, for more tube options.
   
  I also had an idea for an option way to wire the amp for both ECC99 and 6N6Pi options using two DPDT switches to make the changes.  This would allow more options for tubes and tube combo's 
   

   
  Two DPDT switches would be needed, and the throws should be ganged so they are thrown together.
  Probably best put on the rear away from signal paths also.


----------



## HiGHFLYiN9

I getting ready to start this build and have a few basic questions that I was hoping someone might be able to shed a little light onto.
   

 I've found a chassis I'd like to use and it comes in two sizes, 13W x 10D x 3H and 17W x 10D x 3H. I measured out the boards and it appears the 13W x 10D x 3H would fit, but it may be a little cramped. Anyone have a recommendation one way or the other? The transformer is going to be mounted on the top of the chassis FWIW.
 I saw that a few people here soldered the tube sockets upside-down on the PCBs and mounted the PCBs to the bottom of the top plate on the chassis. What size standoffs were you gents using? 1/2"?
 I'm ordering the Rubycons for the power supply at the moment. Newark has the HXC for high ripple current, MXC for standard purpose and MXG which is a miniaturized version, apparently for both. Any opinions on which would be ideal?
   
  TIA.


----------



## nikongod

Quote: 





highflyin9 said:


> I saw that a few people here soldered the tube sockets upside-down on the PCBs and mounted the PCBs to the bottom of the top plate on the chassis. What size standoffs were you gents using? 1/2"?


 
   
  If you want to do this, you MUST solder the sockets to the right side of the board, and all components to the wrong side. The pinouts will be wrong if you flip it.


----------



## HiGHFLYiN9

You're absolutely right.


----------



## runeight

Quote: 





adamus said:


> My original sketch up was indeed a little rushed, and the revised diagram above is correct (cap and resistor layout).
> 
> question is though, can that be done on the boards... probably but i havent looked yet. It may require a trace to be cut.
> 
> ...


 

 You know gents, the original Bijou PS already elevates the heaters to about 40V if you use the components in the BoM. Amphead's mod puts the heaters at 0VDC and this puts the ECC99s under some HK stress but not beyond their maximums.
   
  Or maybe I have missed something important to the conversation. In which case I apologize for the useless information.


----------



## HiGHFLYiN9

Quote: 





highflyin9 said:


> I getting ready to start this build and have a few basic questions that I was hoping someone might be able to shed a little light onto.
> 
> 
> I've found a chassis I'd like to use and it comes in two sizes, 13W x 10D x 3H and 17W x 10D x 3H. I measured out the boards and it appears the 13W x 10D x 3H would fit, but it may be a little cramped. Anyone have a recommendation one way or the other? The transformer is going to be mounted on the top of the chassis FWIW.


 
   
  Looks like I'm going to go with the larger chassis as I'll be mounting the large-ish 70uf Obbligato Film Oil caps in combination with Rubycon 410uf photoflashes on C5.


----------



## METhomas

Would anyone be willing to give their opinion on how this amp and the DT990 600 sound together. I understand that tubes will have a great influence on this symmetry. I am looking toward an amp for these cans and would prefer diy, also looking at the SOHA II, as I would prefer a tube amp.


----------



## gabriel-dan

[size=medium][size=small]Hi,[/size][/size]
  [size=medium][size=small]Here are a few pics of a Bijou I’ve just finished building today. [/size][/size]
  [size=medium] [/size]
  [size=medium][size=small]Only stock parts recommended by cavalliaudio site were used and no mods. I do not know if any of the mods will dramatically improve the sound, but as it is, this amp rocks. My HD650 never sounded so good, simply spectacular. I can't hear hiss or hum of any kind, the amp is dead quiet. [/size][/size]
  [size=medium] [/size]
  [size=medium][size=small]Credit goes to www.vt4c.com for providing the chassis, transformer and misc. at a very reasonable price. Also to Jeff R. from [/size][size=small][size=small]www.glassjaraudio.com[/size][/size][size=small] for offering the bijou and many other kits. It makes life easy for lazy people like me. [/size][/size]
  [size=medium] [/size]
  [size=medium][size=small]Finally many thanks to Mr. Cavalli for offering such a beautiful and high performance design.[/size][/size]
  [size=medium] [/size]


----------



## tamu

Very nice work gabriel!


----------



## pabbi1

That is very pretty - quite a nice aesthetic.


----------



## balderon

Nice job. IMO updating the 6DJ8's with Amperex Bugle Boy improves the mids and highs.
   
  Quote: 





gabriel-dan said:


> [size=medium][size=small]Hi,[/size][/size]
> [size=medium][size=small]Here are a few pics of a Bijou I’ve just finished building today. [/size][/size]
> [size=medium] [/size]
> [size=medium][size=small]Only stock parts recommended by cavalliaudio site were used and no mods. I do not know if any of the mods will dramatically improve the sound, but as it is, this amp rocks. My HD650 never sounded so good, simply spectacular. I can't hear hiss or hum of any kind, the amp is dead quiet. [/size][/size]


----------



## yiancar

Hey guys, 
   
  This is my first post , as also my first attempt on a tube build.
  Well everything is extremly clear to my, excpet one thing, Caps.
  After reading all 236 pages of this thread my initial questions still remain.
  1) are the wima caps so bad for sound?
  2) if yes which brand of caps would help out? (I have seen so many different caps here that my mind is gonna explode)
  3) shall i stick to the initial values or expreriment a bit?


----------



## balderon

Welcome yiancar! Let me be the first to say "sorry for your wallet".
   
  I recommend keeping with the original components and experimenting after your build is working. This would give your ears an opportunity to decide if a change was good or bad. Sometimes the simplest change has the greatest affect on the sound.
   
  You mentioned this is your first attempt building a tube amp. I trust you are versed in the dangers and safety precautions when working with high voltage circuits?
   
  Quote: 





yiancar said:


> Hey guys,
> 
> This is my first post , as also my first attempt on a tube build.
> Well everything is extremly clear to my, excpet one thing, Caps.
> ...


----------



## yiancar

Hey bald,
  Well yea this is my first tube amp but dont worry i have been around electronics for a long time in order to know the safety precautions for hv.  Also my wallet can take a small hit for a nicer sound 
   
  I will take your suggestion, build the amp in its defaults and ill take it from there.
   
  Btw am thinking of jumping into 6h30 as i heard they have a more worm sound. Also having the NFB vr to 0 ohms gives the same audiable results ( not humming or buzzing) as doing the removal mod?


----------



## balderon

It has been my experience humming or buzzing associated with the NFB pot may occur when the frame of the pot is not connected to circuit ground. I do not hear any noise regardless of the NFB setting.
   
  I have not tried 6h30. I rolled the 6n6p but I prefer the ECC99


----------



## yiancar

tnx  am gonna order my kit and will post some pics


----------



## Ant1Xr1st

New 6N1P bias circuit with dc heater.


----------



## nikongod

Why not use a LED or diode string to bias the gain tube? It would save you a lot of effort.


----------



## yiancar

guys ive been inspired by elektor of this month and am thinking of building a remote control for the amp,  is anyone interested so i can start designing?


----------



## fishski13

gabriel-dan,
  looks awesome!  enjoy. 
   
  after nearly 2 years, and a few iterations, i've finally decided it's time to "finish"  my Bijou.  my custom face-plate from FPE shipped today.  "final" tweaks include: regal mod, cap multiplier, amphead mod, shunted PEC pot with TX2352 100K resistors and 150uF M-caps for output caps.  since i've never rolled any tube in the Bijou, i'm looking at getting a pair of of Amperex orange globes to replace the 6N1P.  are these reasonable - NOS and balnced?: http://www.nostubestore.com/2010/04/amperex-orange-globe-6dj8ecc88-holland.html
   
  currently listening to some Jack Johnson with my Bijou and refurbished AKG K240 DF.  excellent stuff!


----------



## balderon

I would like to see some pictures of the finished product! Did you have troubles fitting in the M-Caps?
   
  IMO the best prices can be found elsewhere and often fairly strong and matched tubes. I have several pairs of Bugle Boy 6DJ8 purchased on e-bay or audiogon and have been very happy with the buys.
  
I think the buy now price is worth a try
  Quote: 





fishski13 said:


> gabriel-dan,
> looks awesome!  enjoy.
> 
> after nearly 2 years, and a few iterations, i've finally decided it's time to "finish"  my Bijou.  my custom face-plate from FPE shipped today.  "final" tweaks include: regal mod, cap multiplier, amphead mod, shunted PEC pot with TX2352 100K resistors and 150uF M-caps for output caps.  since i've never rolled any tube in the Bijou, i'm looking at getting a pair of of Amperex orange globes to replace the 6N1P.  are these reasonable - NOS and balnced?: http://www.nostubestore.com/2010/04/amperex-orange-globe-6dj8ecc88-holland.html
> ...


----------



## fishski13

Quote: 





balderon said:


> I would like to see some pictures of the finished product! Did you have troubles fitting in the M-Caps?
> 
> IMO the best prices can be found elsewhere and often fairly strong and matched tubes. I have several pairs of Bugle Boy 6DJ8 purchased on e-bay or audiogon and have been very happy with the buys.
> 
> I think the buy now price is worth a try


 


 will do.  the chassis is sized for a balanced configuration, so fitting the the M-caps wasn't a problem.


----------



## rolotube

fishski
   
  I've been running Bugle Boys for a quite while now & found them to give the best results of all the common front end tubes used in the Bijou.  Orange Globes or just about any of the NOS Amperex 6DJ8 variants should also be excellent.
   
  Big M-caps are WTG.  I'm running 330uF's, which pose some mounting issues, but sound is very, very smooth.


----------



## fishski13

Quote: 





rolotube said:


> fishski
> 
> I've been running Bugle Boys for a quite while now & found them to give the best results of all the common front end tubes used in the Bijou.  Orange Globes or just about any of the NOS Amperex 6DJ8 variants should also be excellent.
> 
> Big M-caps are WTG.  I'm running 330uF's, which pose some mounting issues, but sound is very, very smooth.


 

 thanks.  i'm going to order up some tubes tonight.


----------



## fishski13

i like to buy locally when possible and picked up a pair of these:http://tctubes.com/6DJ8-ECC88-Amperex-A-frame-dimpled-disc-getter-pair.aspx
   
  everything should be coming together by Thursday night!


----------



## fishski13

i got off work this am at 0730, had the tubes in my hands by 0900 and in situ by 0945 
	

	
	
		
		

		
			





.  in addition to the Amperex white print, i picked up a pair of matched Sylvania 6DJ8.  since i socketed cathode bias resistor R2, i was able to just plug in 475R from the parts bin to bias at 5ma with Regal's Mod.  the sonic differences are apparent with the Sylvania, so much so i'm wondering if the former 6N1P with R2=180 was clipping with my K702 and K240 DF?  sometimes i felt there was a "hardness" in the mid-range that i just chalked up to the HPs preferring sand - i never had an issue with my K271 though.  i'm hearing better transients, more treble detail, natural tone and dynamic shadings with my K240 DF.
   
  i took some readings with my DMM with the 6N1P last night and drew out a load line on the plate curves with B+ 253V.  i calculated and measured 0.9V on the cathode.  my y2 DAC puts out 1.4V rms.  my rectifier is EZ81 and i installed the cap multiplier mod (btw Alex, you should add this to the "Tweaks" on you site).  i'm measuring 2.4V on the cathode with 6DJ8 and R2=475.  any thoughts re: clipping?


----------



## fishski13

done...
   
   http://www.amb.org/forum/post3912.html#p3912


----------



## HiGHFLYiN9

I started putting together my kit last night and had a couple of questions.
   
*There's a through hole under V1 that connects to pin 4 on the amplifier boards. What is that used for? *
   
*If I flip the MOSFETs and mount them to the bottom of the board, won't that mess up the pin configuration? *
   
  TIA


----------



## balderon

Quote: 





highflyin9 said:


> I started putting together my kit last night and had a couple of questions.
> 
> *There's a through hole under V1 that connects to pin 4 on the amplifier boards. What is that used for? *


 
   
  This trace is connected to the power LED and it happens to be routed via a through hole under V1.
   
  Quote: 





> *If I flip the MOSFETs and mount them to the bottom of the board, won't that mess up the pin configuration? *
> 
> TIA


 
   
  The pin configuration will be fine as long as you maintain the correct orientation. The easiest way I ensure the correct orientation is to note where pin 1 is on the silkscreen side and on the backside of the board and where pin 1 is on the transistor. When I place the component on the opposite side I ensure that pin 1 is inserted into the correct through hole.


----------



## graematter

I just finished my Bijou tonight and I have some serious humming. This is my first tube amp so I'm sure I have many areas to correct, but I was wondering if you guys could give me some idea as to how to locate the hum. It changes when I unplug my laptop power cord, when I unplug my M2Tech HiFace and sometimes when I touch my NFB pot. I can turn the NFB all the way up to reduce it, but not eliminate it. I have a star grounding system. I have some wires crossing that maybe shouldn't be crossed... maybe? I can post some pictures soon, but I was hoping to get on top of it sooner...
   
  P.S. sounds GREAT besides!
   
  ...the hum is basically its own song though....
   
  grae
   
   
  EDIT: It also has a faint grinding sound when I use the trackpad on my computer....


----------



## johnwmclean

Graematter, I’d double check the input and output from you pot is not mixed.


----------



## fishski13

graematter,
  try shorting the input to ground on the boards of each channel.  if you still have noise, it's probably the amp/grounding/wire management.  if no noise, it's the pot back to the source causing problems.  i'm guessing that if you get a reduction in noise with the NFB turned all the way up, it's the pot to the source.


----------



## graematter

johnwmclean said:


> Graematter, I’d double check the input and output from you pot is not mixed.







 Mixed. As in I'm having shorts or I wired it incorrectly? And I used a jumper between 2 posts on my NFB pot... That's what I was supposed to do right?

 Some other areas of question:

 I have unshielded RCA input jacks... Problem?

 I built it in a wood enclosure - with a piece of aluminum sheet metal on the bottom to mimic a metal chassis to try and pick up any interference... Stupid? 

 The only thing connected to that piece of aluminum is my star ground and the transformer body... And lines ground at the star ground post... Was this a dumb thing to do?

 I have shielded wire running from my input jacks to my ALPS volume pot. I didn't connect the shield of the wire to star ground. The shield is only connected to the ground of the RCA jacks and thus whatever that's grounded to... Could this cause a "ground loop"?

 When I unplug everything (laptop, HiFace) the hum becomes more "pure"... It gets messier when everything is setup.


 I'm using the new Gigaworks DAC with Coax connection from my HiFace. 

 Blue Jeans Cables connecting it all.

 P.S. I also get a buzzing when I move my NFB wires around... But is very manageable... Any advice to completely eliminate?


----------



## fishski13

i would not connect the shield of the chassis wiring to the ground of the RCA - you're adding RFI noise.  just tie the shield to chassis ground, anywhere.


----------



## graematter

I'm at work - I'll try the shorting trick as soon as I get home.





 Some other points of question and maybe concern:





 I built it in a wood enclosure. I put an aluminum plate at the bottom. It's connected to star ground and transformer casing. Thought this would help reduce RF interference... Stupid?





 I have unshielded RCA input jacks. I used shielded wire to connect those to my ALPS volume pot. I grounded the shielding of this wire to the jack ground, but not the star ground... Should I connect it to star? Tried connecting with no reduction at all to hum.





 I'm using the new Gigaworks DAC (coax connect) with a HiFace. All hooked up with Blue Jeans Cables. 





 When I unplug everything from the amp, the hum becomes more "pure".





 My star ground wires cross a bunch of other wires - nothing under any boards or anything. There is a lot of room, so they aren't truly that close. No effect to hum at all when I mess with then though... I think they're fine.





 I'm thinking I will have results when I short the input. Is there a specific way that I have to do this? Can I damage anything by performing this?





 P.S. I get some buzzing when I mess around with the NFB wires - they are my longest hookup wires by far... That ok? The buzz is VERY manageable, but I'd like the "blackness" that I know is acheivable with the Bijou. 





 Hum = Goliath


 Buzz = David





 Graematter





 EDIT: sorry for the double post... Working with an iPhone and I thought my first post was lost... And now I can't delete my first one for some reason... And I like my second one. I'm eccentric - my apologies.


----------



## balderon

Ensure the frame of NFB pot is grounded to the chassis ground and none of the pins on the pot are touching the NFB frame. Also I found it helpful to use a ground loop breaker (simple R/C network) to connect earth ground to chassis ground. I used a 10 ohm 1W wirewound resistor in parallel with a 0.1uF 250VAC capacitor. For a test you could jumper earth and chassis ground but I wouldn't recommend making that permanent.


----------



## johnwmclean

Quote: 





graematter said:


> Mixed. As in I'm having shorts or I wired it incorrectly? And I used a jumper between 2 posts on my NFB pot... That's what I was supposed to do right?


 

 Wired incorrectly, check that you haven’t mixed up the input and output wires of your ALPS volume pot, mixing these up causes a hum that reduces when the volume is turned all the way up.


----------



## graematter

balderon said:


> Ensure the frame of NFB pot is grounded to the chassis ground and none of the pins on the pot are touching the NFB frame. Also I found it helpful to use a ground loop breaker (simple R/C network) to connect earth ground to chassis ground. I used a 10 ohm 1W wirewound resistor in parallel with a 0.1uF 250VAC capacitor. For a test you could jumper earth and chassis ground but I wouldn't recommend making that permanent.











 Very helpful thank you. I had connected earth to chassis without a ground loop breaker - guessing that is causing some big problems. 



 So... Earth ground to Ground Loop Breaker to Star Ground (or somewhere other than star?)



 I built it in wood remember... So almost every single ground I have is going to star. Any I should isolate?



 And when I connect the NFB and volume pot casings to ground, should it be star ground or does it not matter where?





 Still at work... Just wanted to pick up any materials I will need on the way home.


----------



## chobint

I'd wager you're using a USB source aren't you? It is typical for actions like typing or scrolling to cause audio noise when using a USB DAC. As others have mentioned, grounding the input and grounding the NFB pot are good places to start.
  p.s. Take it easy on the spacing. It makes your post more difficult to read.


----------



## fishski13

i wouldn't worry about the chassis - how many tube amps have you seen are built entirely within a grounded aluminum chassis?  lottsa wood my friend.  even my noise prone B22/o22 is wrapped in wood without issue.  
   
  -just take the input wiring signal shield to chassis ground (not input signal ground to the pot) and check for noise.  
  -if you still have noise, short the input to ground at the board.
  -if you still have noise, it's the amp/wiring.  if not, it's the pot wiring or your source.  check your pot wiring and hook up an AC powered dvd player to the input.
  -if you still have noise, try a ground loop breaker as already described.
   
  btw, the white print Amperex 6dj8 for input tubes are soooooper sweet.  the Bijou fronted with a y2, and K240 DF at the business end, is a serious bit of kit.


----------



## balderon

Quote: 





fishski13 said:


> btw, the white print Amperex 6dj8 for input tubes are soooooper sweet.  the Bijou fronted with a y2, and K240 DF at the business end, is a serious bit of kit.


 
   
  Did you get a pair of D-getter 6dj8's?


----------



## fishski13

Quote: 





balderon said:


> Did you get a pair of D-getter 6dj8's?


 

 they're A-getter.  does the D-getter = halo-getter?  i thought the A-getter were moar better ?


----------



## graematter

Quote: 





chobint said:


> I'd wager you're using a USB source aren't you? It is typical for actions like typing or scrolling to cause audio noise when using a USB DAC. As others have mentioned, grounding the input and grounding the NFB pot are good places to start.
> p.s. Take it easy on the spacing. It makes your post more difficult to read.


 


 Correct - USB source. M2Tech HiFace.
   
  And my apologies, the iPhone is a tricky device when it comes to formatting forum posts. On my end it looked like a very aesthetically pleasing and easy to read post; however, I soon found out that it was extremely annoying.
  
  Quote: 





johnwmclean said:


> Wired incorrectly, check that you haven’t mixed up the input and output wires of your ALPS volume pot, mixing these up causes a hum that reduces when the volume is turned all the way up.


 
   
  The hum gets louder as I turn up the ALPS - "equal" to the volume


----------



## balderon

Quote: 





> Originally Posted by *fishski13* /img/forum/go_quote.gif
> 
> they're A-getter.  does the D-getter = halo-getter?  i thought the A-getter were moar better ?


 

 Some say the D-getter is better and often priced much higher. They are more rare than some of the other styles. I was curious what you had purchased. Maybe the later A-frame, dimpled disc getter? If you had a pair of the D-getters I was thinking of asking where you got them and the cost. Someday I want to try a pair of D-getters just to see if it's worth all the hype. Personally I think everyone should try the purple poo whizzbang getter. 
	

	
	
		
		

		
		
	


	




 I doubt if it really matters what style the getter is.


----------



## regal

IMO if the front tubes come come from Holland they are good enough,  for this amp I do recommend 6DJ8's over 6922's due to the low current even with my mod.


----------



## balderon

Quote: 





regal said:


> IMO if the front tubes come come from Holland they are good enough,  for this amp I do recommend 6DJ8's over 6922's due to the low current even with my mod.


 

 I agree the 6dj8's from Holland are desirable but IMO the Bugle Boy or Orange Globe are superior.


----------



## graematter

All fixed - input jacks were not grounded properly. I also replaced all the NFB wires with shielded wires and that eliminated the buzz. The bijou sounds fantastic! The bass is lacking a little, but I hope that improves with more burning in. 



 I purchased VU meters and JLM's buffer kits. This should be placed at the input... Correct? Will this degrade my sound quality? I know the buffers should keep the sound unadulterated, but I'm weary... Any comments?



 And what mods or tubes should I try for a little stronger bass? I have Jeff's kit from GlassJar.



 Graematter


----------



## balderon

^ I have not has an issue with the amount of bass. What headphones are you using?


----------



## gabriel-dan

Quote: 





graematter said:


> All fixed - input jacks were not grounded properly. I also replaced all the NFB wires with shielded wires and that eliminated the buzz. The bijou sounds fantastic! The bass is lacking a little, but I hope that improves with more burning in.
> 
> 
> 
> ...


 

  
  [size=10pt]I have no complains from Bijou's bass reproduction. I find the bass more than adequate and as balderon pointed out, what headphones are you using? I am using HD650 and the bass is perfect for my taste. [/size]
  [size=10pt]Me too I got the kit from glassjar which included ECC88, Try rolling 6DJ8's they might give a bit more punch. [/size]


----------



## fishski13

Quote: 





balderon said:


> Some say the D-getter is better and often priced much higher. They are more rare than some of the other styles. I was curious what you had purchased. Maybe the later A-frame, dimpled disc getter? If you had a pair of the D-getters I was thinking of asking where you got them and the cost. Someday I want to try a pair of D-getters just to see if it's worth all the hype. Personally I think everyone should try the purple poo whizzbang getter.
> 
> 
> 
> ...


 

 here's the tube, except mine have white printing: http://tctubes.com/6DJ8-ECC88-Amperex-A-frame-dimpled-disc-getter-pair.aspx
   
  see here https://www.tubeworld.com/6dj8.htm and scroll down to: [size=xx-large]*6DJ8 Amperex Holland 1970-1976 WHITE printing *[/size]
   
  the tube pictured has a Philips label though, mine has Amperex.  i assume this is similar to what i have.
   
  i think the Sylvania is a really nice sounding tube ( http://tctubes.com/6DJ8-Sylvania-JAN-matched-pairs.aspx ) , and one may prefer it with different HPs, but the Amperex wins out with it's 3D sound colorful tone with the K240 DF.  
   
  tctubes.com has a really nice selection of tubes and really nice people to deal with.


----------



## vlb

Would bigger caps at c3 and c4 lower the -3db freq? I have some spare 1uf auricaps...


----------



## bhjazz

There was some discussion about this a while back.  I found a post from husky...http://www.head-fi.org/forum/thread/277541/bijou-all-tube-futterman-headphone-amplifier/1620#post_4880479 as an example.


----------



## eertelppa

Sorry to butt in here and ask a noobish question. After reading for a while I have a question.
   
  So for DIY related areas of amplifiers (or preamps [not really sure of the difference still new to all of this]) I keep seeing the Beta22 recommended for Solid State, and the Bijou recommended for Tube.
   
  Do those seem to be the two highly respected DIY amps? I guess what I am wondering is what is the general consensus of the high end DIY amps? I am sure there could be a list of 5 or more and each one will have their strengths (and weaknesses) for various cans. I see more and more that an amp selection many times is based on headphone selection so this is a subjective question.
   
  I would be running Grado's (I read millet is suggested) although would prefer not to be limited to only Grados and would want hybrid or all tubes.
   
  Thanks for any advice. The amps yall are making are just superb work, congratulations to everyone doing this. I truly love some of the workmanship some people are putting out.
   
  Sorry for barging in here and asking a question you have seen before but just had to ask, although the smart thing to do is save my questions for a local meet but I am impatient (and maybe save them for a relevant thread).
   
  Thanks again,
   
  Austin


----------



## balderon

Quote: 





> Originally Posted by *fishski13* /img/forum/go_quote.gif
> 
> [snip]
> 
> ...


 
   
  X2. on the Amperex Holland.
   
  I didn't know about tctubes.com. I was hoping to find at least one pair of DuMont 6FD7's. No luck.


----------



## graematter

I have some minor NFB buzzing that reduces significantly when I touch the NFB pot. The pot casing is grounded very well. I have shielded wires for the NFB wiring. 880dt Beyers. I can reduce the buzzing to nothing with the NFB knob at 50%. Any ideas? Or is the only possibility that my ground is not satisfactory?


----------



## fishski13

Quote: 





graematter said:


> I have some minor NFB buzzing that reduces significantly when I touch the NFB pot. The pot casing is grounded very well. I have shielded wires for the NFB wiring. 880dt Beyers. I can reduce the buzzing to nothing with the NFB knob at 50%. Any ideas? Or is the only possibility that my ground is not satisfactory?


 

 is the shield tied to ground?


----------



## nikongod

Quote: 





graematter said:


> Or is the only possibility that my ground is not satisfactory?


 

 This would be my bet.


----------



## audionut

Can anyone suggest some good sources for the 6n6pi? I'd like to try some in place of my JJ ECC99's to see how they sound in comparison. My searches haven't turned up many places to get these from. Thanks, Tommy.


----------



## balderon

http://shop.ebay.com/?_from=R40&_trksid=p3907.m570.l1311&_nkw=6n6p&_sacat=See-All-Categories
   
http://www.tubes-store.com/product_info.php?products_id=15 $10 min order


----------



## funch

Quote: 





audionut said:


> Can anyone suggest some good sources for the 6n6pi? I'd like to try some in place of my JJ ECC99's to see how they sound in comparison. My searches haven't turned up many places to get these from. Thanks, Tommy.


 


      I have the two that came with my Glassjar kit, and four more that I got thru ebay from the Ukraine that I'm not using.
   
       I also have an EZ80. PM me if you're interested.


----------



## audionut

Gentlemen, Thanks for the offers and links for the 6n6pi's, but I just realized via the Bijou website that you're not supposed to use the 6n6pi's if you've done the Regal Mods, which I have. Can anyone recommend any other tubes to roll, either in the input or output stage, that I can try in place of the JJ 6922's and ECC99's that I have in there now? Just looking to experiment a little to see how different tubes (NOS versions maybe, instead of new production JJ's?) might give me a different sound. Thanks.


----------



## balderon

There are many posts, some recent, discussing this very subject.


----------



## kominak

So I've read through the first 70 pages of this thread and I think I'm really going to build this amp.
  Still want to be sure I understood everything right - please correct me if I'm wrong:
   
  1. If I only plan to use the amp with 600Ohm headphones, I suppose I can:
     1a. remove the NFB
     1b. decrease the value of C5 to around 30uF so that I could use quality film caps (the rolloff point would be under 10Hz)?
 2. I always used toroid power transformers in my guitar tube amps, I thought they're better for audio because of their smaller EMI field,
    but now I've read that EI core transformers are better for this amp because of their lower bandwidth
   (thus acting as a filter against radio interference?). Is it really so?
 3. I plan to use NOS Tesla E88CC in V1 position. As it is basically same tube as 6922 is it possible to make regal's mod
    without any other changes?
 4. I plan to use nos 6n6p in V2 position. Can I use either 6n6p or 6n6p-I? Which type is supposed to be better?
 5. How important (in this design ) is it for the V1 tubes to be matched and for V2 tubes to be both matched and balanced?
 (left V1a = right V1a;
  left V1b = right V1b;
  lV2a=lV2b=rV2a=rV2b)
 6. Suggestions for quality coupling/output caps? I know it's a personal thing but I'd still like to get some tips. I prefer detail over smoothness.
   
  Thanks a lot!


----------



## regal

I would recommend at least 50uf with the 600 ohm phones.  Definately remove the NFB,  yes use a EI core for tube amps, NOS Tesla 6922 work well with my mod but I preferred 6DJ8 Amperex tubes because the current is so low (6922 is for higher current applications but they still sound fine.)  I'm no expert on russian tubes but I think all 6n6p's are the same.  Obbligos may be a cap for you to look at but recommending caps is like recommending a flavor of icecream, but avoid electrolytics in all positions of the the amp board (not just the coupling caps).  Oh,  except the cathode bypass:  use a Slimic II 1000uF there.  Also dont forget to use an EZ81.
   
   
   
  Quote: 





kominak said:


> So I've read through the first 70 pages of this thread and I think I'm really going to build this amp.
> Still want to be sure I understood everything right - please correct me if I'm wrong:
> 
> 1. If I only plan to use the amp with 600Ohm headphones, I suppose I can:
> ...


----------



## kominak

Thanks a lot, regal. Do you know if it's important that the tubes are matched/balanced? Haven't found any info about this.


----------



## graematter

I'm now planning to remove my NFB. I will only be using 250ohm Beyer 880dts and think I should be alright. Are my assumptions correct? I bought the kit from Jeff at Glass Jar. As described on the Bijou site, I have to change R1 from 10k to 300. I don't have any more vishay resistors and was wondering if I could place a 300ohm resistor from radioshack. Would this greatly reduce my sound? I have no problem ordering a new resistor and doing this right; however, I'm leaving for college in 5 days and would like to do this now.
   
  Please advise.
   
  Graematter


----------



## regal

Quote: 





kominak said:


> Thanks a lot, regal. Do you know if it's important that the tubes are matched/balanced? Haven't found any info about this.


 

 I really don't think so unless you get a pair that are way off,  the 6N6P you buy are true NOS so that I wouldn't worry about at all.  For the 6DJ8's I suppose it would be possible to have a pair way off but I didn't have in trouble with several different used ebay pairs.


  
  Quote: 





graematter said:


> I'm now planning to remove my NFB. I will only be using 250ohm Beyer 880dts and think I should be alright. Are my assumptions correct? I bought the kit from Jeff at Glass Jar. As described on the Bijou site, I have to change R1 from 10k to 300. I don't have any more vishay resistors and was wondering if I could place a 300ohm resistor from radioshack. Would this greatly reduce my sound? I have no problem ordering a new resistor and doing this right; however, I'm leaving for college in 5 days and would like to do this now.
> 
> Please advise.
> 
> Graematter


 


 I used a ratshack resistor for R1,  no problems,  some think they sound better than metel films in those positions.


----------



## graematter

Thanks for the response. I ended up using a carbon resistor. It sounds great.


----------



## kominak

thanks, regal. So I guess I'll try bijou with some spare tubes I have around first.


----------



## vlb

My dual mono bijou have been running for a while now and it´s the best headphone amp I´ve ever heard. But it needs just a little more bottom end and dynamics before Im satisfied. It should also function as a preamp so it has to match the sq of an arc d250.  
  Im going to:
   
  Amp
  Replace c1 with 2x20uf film (done)
  Replace c3, c4 with 0.68uf film
   
  Ps
  Paralell c1 with another 470uf and a 20uf film.
   
  Im a newbie so please tell me if Im about to do something stupid.


----------



## runeight

This is not an unreasonable plan, although the extra electrolytics might be detrimental to the SQ. Hard to say.
   
  You might try changing in stages as you've already done with C1. Try C3/C4 next, then C5.


----------



## vlb

Im doing it step by step to se the improvements. C5 is already replaced with 120uf film and right now and I think it sounds best without the cathode bypas cap. So the amplifier is free of electrolytics.
   
  Could an extra electrolytic in the ps realy decrease the sq? I thought 2 in paralell would cut the esr in half.


----------



## nikongod

Quote: 





vlb said:


> Could an extra electrolytic in the ps realy decrease the sq? I thought 2 in paralell would cut the esr in half.


 

 When you look at signal current loops, which almost always go through a fat electrolytic cap, absolutely.
   
  From what I have read on the interweb  The issue is seldom ESR in audio-frequency applications. The issue is that capacitors have their own funky distortions which get into the signal through signal current loops. Lynn Olson OR Thorsten Loesch (I cant remember who! More than likely Thorsten, Lynn's style leans more towards push-pull amps to break signal current loops. Read as much as you can written by both of these guys anyways) briefly touched on the subject in his article on designing a SET 300B amp, and the hidden challenges that are easy to overlook and make your amp have "beautiful tone". 
   
  ESR is critical in digital applications, and switching power supplies, but is not really a significant factor at low frequencies. The difference in ESR of 2 different caps at 100khz will make a world of difference in a switchmode power supply, but means nothing at 1khz smack in the middle of the audio band.
   
  On the other hand, the output stage of the Bijou has some PSR, so the inclusion of the caps in the signal current loops is probably not as bad as on a SET amp.


----------



## SBoy

I don't know if this is the best way to post this but I didn't want to create a thread on this.

 I was wondering if anybody has heard LCD-2 on this amp? I am about to purchase a LCD-2 but i wonder if its gonna work wonders with the bijou.


----------



## vlb

2x 20uf film for C1 in the amp and 20uf paralell with C1 in the power supply right now.
   
  It´s a big improvement. The sound is more detailed and dynamic, but never get´s harsh. The bass has improved a little, but I gues it get´s better when i change c3 and c4.
  How do i calculate -3db for c3 and c4?
   
  Thanks


----------



## nikongod

Quote: 





vlb said:


> How do i calculate -3db for c3 and c4?
> 
> Thanks


 

 This is harder than it looks. 
   
  Most people will observe that the 2 caps, and their bleeder resistors are equally sized and apply the basic equation for a high pass filter without more thought.
   
  C3 (to the bottom triode) is calculated in the normal fashion with the -3db point given by the equation:
  f=1/(2piRC) 
  where R is the 470K resistor in this case, and C is the 100nf cap.
   
  However this is not 100% correct! It will get us close enough for most purposes, but dosnt tell the whole story....
   
  C4 is harder. Let me tell you a little story.
  You see that 470Kohm resistor there. yea, thats the one R9 sexxy little bit of DCR. m'hmmm. you look at her and say "hello MS. 470Kohms I would like to put you, my cousin the capacitor, and my buddy pi into a room and let them put their AC signals into you while I take pics to post on the web." but there is a problem with this. Not only are you being very disrespectful to the 470Kohm resistor by even thinking she would entertain an idea such as this but she is doing the deed with the triode brothers (you can see this by looking at the center of the output stage - the diodes are there because the top brother dosnt trust her and wants protection in case she tries to strip his cathode {OK, so these are not actually protection diodes, and I dont think cathode stripping will EVER be an issue with a circuit like this, nor would protection diodes do anything to help that but this would not be as fun of a story otherwise}) and trust me when I say that these guys will put up a fight with sparks and electricity to protect her. Since you are trying to apply signal into what ammounts to being another signal that is in the same phase the impedance of this resistor is actually several meg ohms. OOH SNAP! You were all ready to go and tell this resistor who is boss, and the resistor is like "I can resist much more than you initially thought you limp-leaded capacitor!"
   
link to article that actually explains this
   
  In the end it probably dosnt matter, and I'm just a little bit bored. As long as the high pass filter created by C3/R11 checks out you dont have much to worry about. Use the same cap for C4 so that the circuit looks pretty.


----------



## vlb

I tried swtiching + and - on my speakers and headphones so the sound wouldn´t be phase-inverted. Before I thougt that the soundsstage could become messy in some songs, especialy when preamping my magnepans. The instruments posiotions ar much clearer now and the bass is punchier .
   
  Nikongod:
  Thanks! I appreciate when people take their time to explain things. Now i have some reading to do.
   
  My pretty test setup:
  http://img413.imageshack.us/img413/148/201009041036.jpg


----------



## Coupe

So I am about 130 pages into this post.   Very interesting indeed and also very confusing to follow! 
	

	
	
		
		

		
			




   
  However, I am starting to get the idea.  Unfortunately, I ordered the kit from GJA on September 1st.  I have yet to receive it.  I e-mail this past Sunday and have yet to get a response.  Is Jeff ok? 
   
  Also, I have built a Millet MiniMax and done a lot of wiring in my life.  I am a mechanic and I've done work around the house.
   
  This will be the first time I am working on a HV complex circuit.  I have been reading about how the caps hold charge for long after, and the recommended waiting time is 15 minutes.  Is there anyway to discharge the entire circuit of stored energy after it has been unplugged?
   
  I also am curious about the acronyms and terms used.  It is making it difficult to understand some of the posts.  I'm assuming that O/P means output, but some of the others I am not understanding.  Would anyone mind breaking down some of the acronyms or giving a resource where I can learn them?
   
  I am also trying to understand what the whole nature of bypassing is.  After reading it seems that people use Caps to bypass.  Why?  What is this for?  What does the UF rating actually mean for audio?
   
  If there is any great resource to where I can study audio circuits and have them explained that would be greatly appreciated.  I would really like to understand AND enjoy rather than just the latter.
   
  Thank you so much for all your responses and thanks to Mr. Cavalli for this great schematic.
   
  -Steve


----------



## HiGHFLYiN9

Quote: 





coupe said:


> ...Unfortunately, I ordered the kit from GJA on September 1st.  I have yet to receive it.  I e-mail this past Sunday and have yet to get a response.  Is Jeff ok?
> 
> Also, I have built a Millet MiniMax and done a lot of wiring in my life.  I am a mechanic and I've done work around the house.
> 
> ...


 
   
  Jeff can take a few weeks to get your kit together, nothing to worry about. I found a nice easy tool for myself (a non-engineer) was the MAKEzine series (MAKE:Electronics). It's not as dry as a textbook. μF is a microfarad, μ meaning micro or 10-6 and farad is a unit of capacitance. 99% of capacitors I've seen use μF, occasionally you'll see nF or nanoFarad. There's some great articles online regarding bypassing so I recommend a google search rather than trying to explain it myself. Also for lots of info on audio circuits, check out http://www.pmillett.com/
   
  As I know it, bypassing an electrolytic with a film cap can have sonic benefits, and bypassing a large cheap film cap (e.g. Solen) with a nicer quality film cap can also be beneficial. Most people recommend 1% or less for a bypass cap value. I've seen bypassing in both coupling and power applications.


----------



## fishski13

Quote: 





coupe said:


> This will be the first time I am working on a HV complex circuit.  I have been reading about how the caps hold charge for long after, and the recommended waiting time is 15 minutes.  Is there anyway to discharge the entire circuit of stored energy after it has been unplugged?
> 
> 
> -Steve


 

 i would not dick around inside the Bijou without using a means to discharge the caps.  just get a 10K-30K 5W wirewound resistor and solder/insulate wire leads on the ends and terminate with insulated alligator clips.  i usually just keep one end clipped to safety/chassis ground and touch the other end to the caps i need to discharge.


----------



## funch

I just had an interesting experience with one of my Bijou boards. I had disassembled my amp a few days ago in order to replace the
  chassis. I was picking up several items, and placed one of the amp boards on top of my hand to hold it. I felt a slight stinging and
  thought it was probably a clipped lead on the bottom of the board, but it persisted. Turned out that it was the C5 cap, so I measured
  the voltage, and even after several days it still read 42 volts. I measured the other board, and C5 on that one read 52 volts. Guess next
  time I'll make sure to discharge things.


----------



## fishski13

Quote: 





funch said:


> I just had an interesting experience with one of my Bijou boards. I had disassembled my amp a few days ago in order to replace the
> chassis. I was picking up several items, and placed one of the amp boards on top of my hand to hold it. I felt a slight stinging and
> thought it was probably a clipped lead on the bottom of the board, but it persisted. Turned out that it was the C5 cap, so I measured
> the voltage, and even after several days it still read 42 volts. I measured the other board, and C5 on that one read 52 volts. Guess next
> time I'll make sure to discharge things.


 

 i had sparks fly when my crescent wrench touched C5 and chassis while trying to remount one of my boards.


----------



## yiancar

Hey guys, just a quick question on the Rcore transformer (r80-36). It has a 6.3v secondary with a CT. Each of the CT is equal to 3A right? so connecting only the gray wires(without the CT) will give me 6A or still 3 A?. If the above is not correct, parallel connection with the 2 6.3v secondaries will give me 6 A ?


----------



## PoulE

Hi 
  I new, and i have just got the Bijou from Jeff, and I'm gonna go for both Regals's and Ampheads Mod's
  I guess it will be good to do that in the  beginning.
   
  Im going for Ecc99 goldpins , ..... AND ,  >>>is it importend that these 2 tubes are matched balanced and so on ,
  or shall i just order 2 ?????
   
  Thanx
   
  Poul from 
  Danmark


----------



## adamus

just order two, they'll be near enough.
   
  Personally i wouldnt do ampheads mod straight away, but regal mod i would.


----------



## Coupe

About the Regal mod.  Can you still use Jeff's Kit and it will work?  or different tubes need to be used?


----------



## PoulE

Adamus , thank you , I'll guess I'll only do the Regal mode in beginning ..
   
  2 more Q 
   
  1 , is it importend what the box is made off .. alminium ,  stell, or another stoff  ??
   
  2 .  I want the tubes to be on top of box, and the ez81 , should then be wired up ..
        is there something I shall take care off , or speciall know ??
   
  ups 3 Q 
   3 , shall the solder be with silver in ??
   
  I know how to solder, but first time I do a  high voltage , And i'll be carefull
   
   
  Coupe , and Yes , as I understand you can still use it , but have to change R2 after what kind off tube you want 
   
  Poul  ( broken english ) 
   
  Danmark


----------



## PoulE

It aint easy , I have tried to buy the stuff for Regals mod ,
  ok with 10 k R at Mousers
  but the  30k 1% 2w R , they sell only minimum 2500, and I nedd 2 Resistors 
   
  Thank you !!!
   
  Some one who know where to buy ??
   
  Thanx
   
  Poul


----------



## particleman14

i got all my resistors for regal's mod at www.partsconnexion.com


----------



## Coupe

Ahh its cool man.  Thanks for the help.  Seems like Regal's mod is a no brainer.
  Perhaps purchase amphead's necessary parts and see how everything sounds first.
   
  Definitely can't wait to build this kit.  Take time and enjoy this one.


----------



## PoulE

Particleman , I have tried to look at the link, and I can easy find the R 5-6-7
  but I cant find the R2 , 30k 2w 1%
   
  Or maybe the 1% is not so importend ??
   
  Poul


----------



## fishski13

Quote: 





poule said:


> Particleman , I have tried to look at the link, and I can easy find the R 5-6-7
> but I cant find the R2 , 30k 2w 1%
> 
> Or maybe the 1% is not so importend ??
> ...


 

 for a plate/anode resistor, you don't need %1 tolerance; %5 is fine.  1% tolerance resistor at higher wattages will cost some $$$.


----------



## nattonrice

Kiwame ftw!
  http://www.partsconnexion.com/product11671.html


----------



## particleman14

love those little green guys


----------



## PoulE

Ok , the R3 in 5% I can get in Mouser , so I'll order them there ...
   
  Thank you , until now ..
   
  Im sure there will be more Q later ...but at moment Im collecting , and later on start building


----------



## bhjazz

Quote: 





nattonrice said:


> Kiwame ftw!
> http://www.partsconnexion.com/product11671.html


 

 I think those are the ones I bought as well.  Can't tell right at the moment...stuck at work!
   
  Have a great day, gentlemen!


----------



## mobayrasta

Quote: 





sboy said:


> I don't know if this is the best way to post this but I didn't want to create a thread on this.
> 
> I was wondering if anybody has heard LCD-2 on this amp? I am about to purchase a LCD-2 but i wonder if its gonna work wonders with the bijou.


 


  I have the LCD 2 and a Bijou made by dBel. I do not have any mods done just the straight Bijou. It sounds great with the Bijou, probably the best mids I have ever heard. Great highs and decent bass. Bass could be a little tighter, but is still really nice and goes LOW. I am using some really nice amprex tubes that I got from Don. Have no clue how it would sound with regals mod but I am sure it would be even better.


----------



## bhjazz

Quote:


poule said:


> but I cant find the R2 , 30k 2w 1%
> 
> Poul


 
  Poul - be careful: R2 is not the 30K 2W 1%.  R3 is the 30K 2W!


----------



## balderon

Quote: 





mobayrasta said:


> I have the LCD 2 and a Bijou made by dBel. I do not have any mods done just the straight Bijou. It sounds great with the Bijou, probably the best mids I have ever heard. Great highs and decent bass. Bass could be a little tighter, but is still really nice and goes LOW. I am using some really nice amprex tubes that I got from Don. Have no clue how it would sound with regals mod but I am sure it would be even better.


 

 I have considered getting a pair of LCD-2's and I am not convinced the Bijou has enough kahunas to drive them well. What output caps does your Bijou have?
   
  Thanks


----------



## PoulE

BHJazz , I know , it was a mistake i wrote R2 , not R3
  I looked , and i forgot the right number when Write  ..
	

	
	
		
		

		
			




   
  well , today i have got the ccr 99 - goldpins , form  > Tupe-town, and the resistors from  > Mouser  
  later on i'll maybe try a little tuperolling 
   
  so , one day start building the bijou , and in the end ill put my grado's on ..;O)


----------



## PoulE

Can someone plz tell me the right way to do the mosfet and the headsink conection ,
   
  I  understand that I connect them with a bolt ...
  and the grey paper is between mf/hs ???
  there is a litte brown dippedut also in the bag also  , for the mf/hs too ???
   
  PLZ tell me 
   
  Thanx 
   
  Poul


----------



## PoulE

If im right ,
  then a bolt > brown dippedut > Mosfet > grey 'paper' > heatsink , and then conected , Right
   
  Poul


----------



## balderon

The intent of the insulator ("grey paper") and shoulder washer ("brown dippedut") is to ensure the MOSFET and heatsink remain electrically separated.
   
  A picture is worth 1000 words.
http://www.aavidthermalloy.com/products/standard/access/kits.shtml


----------



## Coupe

Hello all!
   
    So I finished the entire thread!  However, I can barely remember it all. I have heard you guys mention navships.   Where can I purchase this?
  What capacitors have the most influence?  It seems the most recommended is C5 and C6.  Is that the amp board caps only, or the PS also?  I will be using predominantly high impedance headphones.  Which caps would you recommended and where can I buy them?  I also have K701s what caps would you recommend, if I wanted to use those also?
  Does anyone have a link for the resistor sockets for R2?
  What is the difference between the GJA kit pot and stepped attenuators I hear about often?
  If I wanted to air wire the tube sockets, what is a good practice?  Anyone have any tips to secure it to the top of the case so they stick out?
   
  Thank you so much for all your responses.  This thread was a really fun read!


----------



## particleman14

hah, I just ordered from him last night, here you go  http://stores.ebay.com/Johns-Silver-Teflon-Wire-Shop
   
   yes for amp boards, I am using 200uf oil run caps for my c5,  no c6 bypass,  .1uf teflon russian ft-3 caps C3-C4.    I also used elna silmics for the electrolytics. and mundorf mkps.  I got all this stuff from https://www.partsconnexion.com
   
   With k701 (62 ohms) 200uf this is about a 13hz -3db corner freq.   http://www.v-cap.com/coupling-capacitor-calculator.php    which is the limit I'd go as far as headphone impedance in my setup.    cap choice is up to personal taste and your wallet. 
   
  The GJ pot is an alps RK27 pot which is conductive plastic.  some say stepped attenuators sound better, check out dact, goldpoint,.   again this choice depends on taste and your wallet. 
   
  I've seen people air wire their tubes before, but I'm sure you'd want the wires to be as short as possible..  check partsconnexion link they have tube mounts for the top of your case..
   
  keep working that search button and happy building, the Bijou is a really nice amp. post pics!


----------



## Coupe

Wow, great information.  Thank you!
   
  I'm sorry, but I have no idea what 13 hz -3db corner freq means.  I will have to look that up. 
   
  So what does a bypass capacitor mean?  You mean you have no caps in c6?  Does this mean you jumper the connection?
  When you say electrolytics does that refer to capacitors also?  Where do these electros go?
   
  Which do you think would be the primary capacitor position to upgrade for sound quality?
   
  I tried to search under socket for the resistor sockets and I couldn't find any. 
	

	
	
		
		

		
		
	


	



   
  Are there any recommendations for audio adaptors (RCAs and Headphone out) that have a good balance of value and quality?
   
  I think I read that 24 awg wiring is proper?  Or should there be higher or lower awg for different parts of the circuit?
   
  Thank you.


----------



## particleman14

I suggest you read through the thread again there is lots of info i can't recall at the moment.  but c5 and c6 seem to be the ones most people mess with... try a search in this thread.


----------



## Coupe

Is there any input on recommended headphone and RCA connectors?


----------



## PoulE

Thank you Balderon 
  and Coupe, you just asked what I wanted to ask about, the airwiring the tubes to put on top of the box 
	

	
	
		
		

		
		
	


	



   
  when make the wiring , what kind of kabel shall I use , and is it the same I shall use to the Airwiring,
  and shall the kabel to the air be in and out eachother ??


----------



## particleman14

I use what connectors look good and don't cost an arm and a leg  again check partsconnexion, that is where i got all those things...


----------



## balderon

Quote: 





coupe said:


> Wow, great information.  Thank you!
> 
> I'm sorry, but I have no idea what 13 hz -3db corner freq means.  I will have to look that up.
> 
> ...


 
   
  I would suggest revisiting Cavalli Audio website as Alex recommends minimum wire size. My preference is to use 600v 20awg for B+ and 18awg for heaters.

 http://www.cavalliaudio.com/bijou/main.php?page=wiring


----------



## balderon

Quote: 





> Originally Posted by *Coupe* /img/forum/go_quote.gif
> 
> <snip>
> 
> If I wanted to air wire the tube sockets, what is a good practice?  Anyone have any tips to secure it to the top of the case so they stick out?


 
   
  There are two common methods to extend tubes out the top of the chassis. You can mount the components on the reverse side of the circuit boards and mount the boards below the chassis top. Or you can purchase "chassis" mount tube sockets and air wire to the circuit boards. Air wiring the the sockets will increase the risk of developing a hum from the close proximity of the AC heater and signal wiring. Twisting the heater wires and isolating from the signal wires should help reduce the risk. It's very important to use 600v insulated wires for the B+. Hopefully others will chime in with their suggestions.


----------



## Coupe

Quote: 





balderon said:


> I would suggest revisiting Cavalli Audio website as Alex recommends minimum wire size. My preference is to use 600v 20awg for B+ and 18awg for heaters.
> 
> http://www.cavalliaudio.com/bijou/main.php?page=wiring


 


 Durr, You think so much that you forget the obvious.  Thanks man.
  
  Quote: 





balderon said:


> There are two common methods to extend tubes out the top of the chassis. You can mount the components on the reverse side of the circuit boards and mount the boards below the chassis top. Or you can purchase "chassis" mount tube sockets and air wire to the circuit boards. Air wiring the the sockets will increase the risk of developing a hum from the close proximity of the AC heater and signal wiring. Twisting the heater wires and isolating from the signal wires should help reduce the risk. It's very important to use 600v insulated wires for the B+. Hopefully others will chime in with their suggestions.


 

 Well I guess I'll let the cat out the bag.  I want to have my tubes mounted like


----------



## jdkJake

Hmmm, so you expect the Bijou to bring you solitude huh?

 Not sure if that is ironic or wistful?


----------



## Coupe

HAHAHAH.  
	

	
	
		
		

		
			




   
  Was talking about mounting angle, but sure why not?
   
  *edit*  I ordered a nub turd of wire from navships!  Is that wire rated for 600v?  I couldn't find where it spoke of insulation rating.
  I might be a total noob, but I can't find where female headphone jacks are located on parts connex.
Good RCA?
  Also, where can you find resistor sockets and the mounting posts for the PCB (when doing inverted install)?


----------



## Coupe

Can anyone help?


----------



## stixx

Parts connexion doesn't seem to carry female headphone jacks...
  The best are from Neutrik (Switzerland), maybe Mouser carries them- Sure they carry other brands.
   
  Mounting posts are called stand offs...


----------



## Coupe

Thank you so much!  I was able to find the Neutriks!  I think i have the right sockets for R2.


----------



## adamus

hopefully over the next couple of weeks i will get time try a salas Hv shunt reg for the HV power supply. I'll report back with any observations. The current supply is pretty good, but the Salas shunt promises even better performance. With regal mods, 6n6p @ about 22ma + 5ma 6dj8 * 4 = 108ma.
   
  Giving a bit of extra room for the shunt supply i will aim for 120ma, 25 ma for the shunt...... this thing will need a big heatsink which may scupper my plans!


----------



## balderon

.


----------



## pabbi1

After shipping out a quad today, I have one quad of the Rubycons left, so one final lucky builder can claim them. This represents the last of 138 that I have supplied to Bijou builders. Hope they have worked well.


----------



## adamus

salas shunt is is in and working.
   
  it basically sounds like a different amp. tone is diffierent (less dark). its less dark but not overly bright.
   
  Give it a go, the salas circuit is easy to breadboard. the side p[anel of a hifi2000 case can just about cope with the heat, but its not ideal.


----------



## ujamerstand

Which version of the supply did you use? Was it this one? http://www.diyaudio.com/forums/power-supplies/134801-simplistic-mosfet-hv-shunt-regs-97.html#post2084348
   
  Also, did you kept the tube rectifiers? Any filters after rectifying?


----------



## adamus

http://www.diyaudio.com/forums/attachments/power-supplies/188092d1284634667-simplistic-mosfet-hv-shunt-regs-sshvopt.gif
   
  solid state recitified, crc filter then the salas shunt. I cant say if it improved anything, but it did sound different. the reg alex used is pretty good, but theoretically the salas is better. 
   
  the shunt is now out of the bijou. and the bijou is getting ready to be transported and sold.... served me well and i will miss it - great amp
   
  its being replaced with a c3g or d3a (testing both) parafeed amp. Salas shunt > CCS > c3g / d3a (led biased)


----------



## ujamerstand

Cool stuff. Makes me want to try them out!


----------



## herro

I'm considering trying this build. What are the smallest enclosure dimensions I could get away with while still having ideal spacing between components? I am considering the HWCHAS series (http://www.hammondmfg.com/HWCHAS.htm) or the 1441 (http://www.hammondmfg.com/dwg20CWW.htm). What sizes of these two would be appropriate. Any other similar recommendations would be appreciated (preferably <$150). I am wanting to internalise the transformer, but want the tubes external.


----------



## herro

I've been going through every post in this thread, I'm about 1/3 the way through. Could anyone else post/quote pics of their build and give me approximate measurements of their enclosure?


----------



## adamus

http://www.modushop.biz/ecommerce/cat154_l2.php?n=1
   
  the 1gx287 (300mm x 230mm) is ideal.


----------



## herro

Thanks a lot. I've been looking at those enclosures are they are nice. I may go with one of these. However it seems my original idea of using HWCHAS from hammond may have the appropriate dimensions (http://www.hammondmfg.com/HWCHAS.htm), minus ~1.5" from each side because of the thick wood. The height is similar to yours too, ~3". Do you think heat would be much of an issue with the wood? Only the top and bottom plates are metal.


----------



## adamus

with tubes top mounted, you wont have any heat issues.


----------



## herro

What are the approximate dimensions of the r-core vs. the 270? And are the modifications to use the r-core strenuous?
   
  I was going to get the r-core because it seemed that I could get away with getting a shorter enclosure, but if the enclosures I am looking at will fit both I would probably just go with the 270. What are the pros/cons of using each transformer?


----------



## balderon

The dimensions are available online for each transformer. I do not have experience with the r-core and I will limit my comments to the 270/370. I do know many have used the r-core without problems. It has been my experience the 270/370 become extremely hot after a couple hours use. The general consensus is the high heat is common and it is likely the 270 will continue to function without fault for a long time. In my case I decided to upgrade the transformer as I do not share that opinion.


----------



## particleman14

I experienced the same heat issue with my 270.  As a result I bought a 6.3V ac transformer (hammond 167Q6) to power the tube heaters.  this greatly reduced the heat on my 270dax.  I would recommend if you are worried about heat.
  here is my Bijou.. 

  the smaller transformer provides power to the heaters.


----------



## regal

Its always good practice to have a separate transformer for heaters for many reasons.


----------



## herro

I was thinking that because I do not have too much time on my hands I would start with an all-internal build, and then later get sockets which i could easily mount externally. I think I may be leaning towards the r-core though.


----------



## herro

Does anyone have a BOM for mouser/digikey for this build? Might consider sourcing the parts as it may be a bit cheaper over the kit


----------



## Region2

Quote: 





herro said:


> Does anyone have a BOM for mouser/digikey for this build? Might consider sourcing the parts as it may be a bit cheaper over the kit


 

 Try checking their website sometime:
   
http://www.cavalliaudio.com/bijou/main.php?page=ampparts
   
  It's fairly quick to order all the parts off of mouser.  It'll probably take you 30 minutes to do so.


----------



## herro

Quote: 





region2 said:


> Try checking their website sometime:
> 
> http://www.cavalliaudio.com/bijou/main.php?page=ampparts
> 
> It's fairly quick to order all the parts off of mouser.  It'll probably take you 30 minutes to do so.


 

 I've read it, I was just wondering because I don't have much experience with DIY audio projects (although I have experience with other electronics), I'm not sure if spending more for a better component that does the same thing (other than caps and such) is worth the extra cost.


----------



## holland

Quote: 





herro said:


> I've read it, I was just wondering because I don't have much experience with DIY audio projects (although I have experience with other electronics), I'm not sure if spending more for a better component that does the same thing (other than caps and such) is worth the extra cost.


 


 Which better components?  There's not much (component-wise) to an all tube amp like the Bijou.  Resistors?  Sure, order whatever strikes your fancy.  For the boutique stuff you may need to get it from a different source.  I just used the plain old Vishay-Dale resistors.  I splurged on the output caps (big film with no bypass).
   
  BTW, since you are a newbie, spend *alot* of time on layout and plan your build.  It will take as long as the build itself to measure and properly layout your build and to isolate (or separate) the power section from the audio side.  It is important to keep wires tight and separated and not throw everything into one big giant bundle.  One thing I do is to keep chassis and signal ground separate via a ground loop breaker...chassis ground is AC earth.


----------



## herro

I should be OK for size and spacing, I'm planning on getting on of the hifi2000 2U enclosures a few people have used here, and including a gamma-2 dac in the same unit as well.


----------



## ericj

Considering diving back into my Bijou for some tweaks. I need to repair my ladder attenuator and i hadn't done the input wiring correctly in the first place (I have shielded wire and didn't think to use it). I may also replace the NFB pot with a rotary switch and discrete resistors, and i think i hear a slight buzzing that the amphead mod may resolve.
   
  I also have a Stancor choke with almost exactly the same specifications as the Hammond 158L. Considering I'm running 6N6P and 6N1P-EV tubes (and EZ81 rectifier), are either of the choke supply mods likely to work well for me?


----------



## holland

Quote: 





ericj said:


> Considering diving back into my Bijou for some tweaks. I need to repair my ladder attenuator and i hadn't done the input wiring correctly in the first place (I have shielded wire and didn't think to use it). I may also replace the NFB pot with a rotary switch and discrete resistors, and i think i hear a slight buzzing that the amphead mod may resolve.
> 
> I also have a Stancor choke with almost exactly the same specifications as the Hammond 158L. Considering I'm running 6N6P and 6N1P-EV tubes (and EZ81 rectifier), are either of the choke supply mods likely to work well for me?


 

 The choke supply mods should be fine.  The CLC filters should be targeted at the ripple frequencies before regulation.  If you have issues with B+ you may even be able to use a larger choke with lower resistance to allow for more power, or rather the full range of the regulation section.


----------



## walangalam

balderon, in your bijou, what are those black washers that dress up the tube holes in the top panel?  Did you make those?  They look really cool and I like to have those too in my build.


----------



## balderon

Quote: 





walangalam said:


> balderon, in your bijou, what are those black washers that dress up the tube holes in the top panel?  Did you make those?  They look really cool and I like to have those too in my build.


 
   
  Thanks Walangalam. The socket covers are custom. They were cut from aluminum billet and then powder coated. The top drawing depicts the placement of three holes I used to mount the covers. I threaded each of the holes to mount small studs. I used a small nut on each stud to secure each cover to the top. All dimensions are in mm.


----------



## herro

Where can I get some of those knobs with the LED ring around them like the one Ferrari (?) had in his build?


----------



## balderon

The knobs are DIY. Ferrari and others described how to create the back lit illuminated knobs. Head-fi's search engine is your friend.


----------



## Avro_Arrow

Is this the one you mean?
  
  Quote: 





herro said:


> Where can I get some of those knobs with the LED ring around them like the one Ferrari (?) had in his build?


----------



## herro

Yes thank you, something like those. I think I may also be reconsidering the locking jacks, as I've been hearing from a few mates that do DIY audio projects that locking generally isn't the best idea for panel jacks. I might be also considering the switched m-series jacks by neutrik. If anyone could recommend something similar of high quality, that would be great too. The idea behind using a switching jack is to maybe use the amplifier as a pre-amp for a larger system in the future, but from reading this thread people have said it would have too much gain.


----------



## herro

Supposedly the height of the GALAXY Maggiorato (hifi2000) case is 80mm (although it states its a 2U, shouldn't that be closer to 90 mm?). I'm assuming the 80 might be internal useful height. The hammond 270 dax happens to be 79.5 mm tall. Does anyone happen to have experience with this case the the transformer? Is it fine to mount it in a horizontal position if it poses a problem, or am I better off getting the r-core?
   
  It seems as though Angela has the best price for the transformer ($47). However, shipping to my location is 20-40 dollars, so I'm just going with Mouser ($70) as I am doing an order with them for my accessories. So far, all my accessories/hardware (jacks/inputs, transformer, etc.) are about $125 shipped @ Mouser. I wanted to go with digikey but they do not seem to have a lot of the items I want. I've yet to choose a good switch/knobs, so the entire project is going to cost about ~$350-75 not including an enclosure. The hifi2000 case I'm aiming for is only about $40-50, but shipping from Italy brings it to about $100 extra, bringing it just shy of $500. I do plan on also incorperating a gamma-2 DAC into the build as stated before, so perhaps looking at about $610 for a finished Bijou+gamma2.
   
  Planning on buying my bijou kit tonight or tomorrow. Just bought my HD 650s tonight.


----------



## walangalam

Quote: 





> Originally Posted by *balderon* /img/forum/go_quote.gif
> 
> Thanks Walangalam. The socket covers are custom. They were cut from aluminum billet and then powder coated.


 
   
  Thanks.  I dont have the resources to do that, but at least I could use the dimensions for them.  Kit arrived today so I will be busy this weekend.


----------



## balderon

Quote: 





> Originally Posted by *herro* /img/forum/go_quote.gif
> Is it fine to mount it in a horizontal position if it poses a problem, or am I better off getting the r-core?


 
   
  Transformers may be mounted in any orientation however it's good practice to ensure any convection cooling is not obstructed.


----------



## graematter




----------



## herro

Ordered my kit last night, can't wait. My HD 650's are coming soon as well. I've been compiling my list of components I'm going to order soon. I don't mind spending a little bit on extra components to make the build look nice, that's why I enjoy DIY mostly. Hopefully it will end up looking as good as it sounds. Here goes:
   
  Mouser:
   

 IEC Socket [ fuses ]
 Hammond DAX270 Transformer
 Neutrik 1/4" Phone connector [ gasket ]
 - would appreciate other good phone jack recommendations
 Neutrik RCA Connectors with matching gaskets [ red | gasket ] [ white | gasket ].
 - edit: gasket picture here: http://www.neutrik.com/client/neutrik/media/view299/Media_1282449486.jpg . They come in various colours so I can match them with the RCA colour.
 - I also found these plastic hinged covers. I was thinking of maybe using these for the RCA at the back, since I'm thinking about building a DAC into the same chassis, and the ports won't be used as often if I do so. I'll get a few of these in case I change my mind.
   
  Modu.it:
   

 GALAXY MAGGIORATO (HiFi 2000) Chassis [ 1GX383 , 330x230 mm]
 - All black/black faceplate version (worth getting the 1 cm aluminum one? It's quite thick)
   
  vt4c.com:
   

 Brass/gold coloured tube protection frames (not sure of this yet, a bit pricey. can anyone recommend a cheaper source?)
   
  I suppose that's it for now. Essentially all I need now are my knobs and a nice switch for the front. One look I'm going for is an all black body with brass coloured/gold plated knobs (and tube frames if I decide on those). A similar coloured switch too, if I can get my hands on one. Alternatively, I'm also thinking about a more modern look (LED ring around knobs similar to some DIY found on the forums, LED power switch).
   
  If anyone could give me some component recommendations based on my selections, that would be great too. Hopefully I can place my order before the weekend is through.


----------



## bhjazz

Be sure to check their prices against audiokit.it as well.  Audiokit sells Galaxy chassis.  Seems a lot of Italian onlin-ers sell that.  Ha!
   
  Good luck!
  
  Quote: 





herro said:


> Modu.it:
> 
> 
> GALAXY MAGGIORATO (HiFi 2000) Chassis [ 1GX383 , 330x230 mm]
> - All black/black faceplate version (worth getting the 1 cm aluminum one? It's quite thick)


----------



## herro

Thanks. Modushop is a bit cheaper, especially for international orders (shipping is actually more than the case itself, I wish I could find something similar here).


----------



## graematter

Need some advice: My B+ is around 230v and then climbs up while I'm testing it. The C1 capacitors on the channel boards are puffed up. The power supply capacitors appear slightly puffed as well (should I be concerned?). I can replace the mosfets and the caps, but I want to get to the source of the problem. (Is it just that the mosfets blew and the B+ has been allowed to run too hot causing the caps to puff?) The amp sounds alright, but is definitely lacking. What has been going wrong? Please let me know any measurements or additional information you need.
   
  Graham


----------



## ujamerstand

I'd avoid turning the amp on till you isolate the issue. If its the large caps that's puffing up, handle them with care. You are probably running them over their specs and they might explode.


----------



## holland

it's hard to say what is causing the caps to blow.  it could be a couple of things, over spec on heat and/or voltage.  narrow down your voltage rise to determine if it's the current draw that is diminishing or if it is something else (transistors in the PS).  it's probably the transistors, but just a guess.  you can measure current draw via the voltage drop across R7 or R8 or both.  It should be fairly consistent.  while you're doing that, measure the voltage out of the rectifier and the heater voltages.


----------



## graematter

The voltage drop across R7 and R8 is 17v. Heater voltages are 66v. I'm so sorry, but how do I measure the voltage out of the rectifier?
   
  P.S. The B+ is reaching 268v now and trimpot has no effect.


----------



## holland

Quote: 





graematter said:


> The voltage drop across R7 and R8 is 17v. Heater voltages are 66v. I'm so sorry, but how do I measure the voltage out of the rectifier? And the large caps in the PS aren't terribly puffed up, I might have been paranoid. It could just be the plastic casing rising a little due to heat expansion.
> 
> P.S. The B+ is reaching 268v now.


 


  66V heater?  do you mean 6.6v?
   
  The rectifier should be pin 3 as the DC output.  The other 2 pins are AC voltages from your transformer.  Measure those voltages too.  They should be reasonably close to the transformer rating, maybe a tad higher.  Assuming you are using the 270DAX, it should be approximately 260VAC (a tad higher as you shouldn't be fully loading your xformer, maybe 265VAC?).
   
  What are the voltages of your caps in the PS?  You should have 400-450V caps there.


----------



## holland

http://www.duncanamps.com/tdsl/show.php?des=EZ80
   
  EZ80 datasheet.  pin 1 and 7 are AC to be rectified.  pin 3 is DC.  pin 4 and 5 are heater voltages, probably AC unless you did a tweak for DC heaters.


----------



## graematter

Thank you for the assistance. My knowledge is not vast, but I'm trying hard to keep up. I have 450v caps in the PS. I'm using the 370DAX and the EZ81. Pin 4 is 8.1VAC and Pin 5 is <1VAC. Pin 3 on the EZ81 is 440V DC. Pin 1 and 7 are at 365VAC. I'm measuring all of these to the Star G. Is that the correct method? And why are these voltages so crazy high?
   
  P.S. I built it from Jeff's GJA Kit. The only tweak I have done from the kit is to remove the NFB.


----------



## holland

http://www.cavalliaudio.com/bijou/images/250VBijouPSVoltages.gif  A good reference for the voltages you should see.
   
  Pin 4 and Pin 5 should be relative to each other, but I'm not sure it matters here.  You should be getting ~6.3VAC.
   
  Pin 1 and 7 do seem high.  Of particular concern is Pin 1 and Pin 7, which drives everything high and running your PS out of spec, probably.  Double check your transformer is the 370 DAX and that your wiring to the transformer input is correct for where you live.
   
  Are you in the US?  My guess is you are in a place with 240VAC mains and you wired it for the US which is 120VAC.


----------



## graematter

I'm in the U.S. 120v mains. I checked the wiring again and it appears to be correct. I have been playing music through it for some time. I consistently get 8.1V for the heaters.


----------



## balderon

Quote: 





graematter said:


> I'm in the U.S. 120v mains. I'll check the wiring again, but the amp has been playing music. I consistently get 8.1V for the heaters.


 







 8.1v for the heaters will burn out ALL of the tubes!!! The maximum should be no higher than 6.5vac. Did you use blue/black wired together and brown/white for 120v mains? The HV output of the transformer and the heaters should be measured relative to the transformer. With the transformer disconnected from the amp you will likely read ~6.9vac for the heaters (both green wires) and the HV should be 260+ when measured red/yellow stripe to each red.


----------



## graematter

Correct, blue/black and brown/white. And it is for sure a 370DAX.


----------



## balderon

It does sound like something may be wrong with your transformer. I have a known good 370DAX once used in the Bijou. If it would help I could measure the resistance of the mains/outputs or power it up and measure the voltages. Let me know.


----------



## graematter

I disconnected the transformer. The voltage from each red wire to the red/yel is 390v. And each green wire to the grn/yel wire is 11v. What should I do?


----------



## graematter

Thanks balderon, whatever you think would help. I'm just at a complete loss. Would my amp be playing music with all of these high voltages? I ask because maybe i'm just getting faulty readings or something... Please advise


----------



## balderon

I would not be surprised the amp would work... for a little while. With the high readings the risk of smoke and fire is severe. My guess is something is seriously wrong with the transformer. I measured the resistances on the primary and secondary. Are yours similar to mine?
   

blue/black​brown/white​6.5 ohm​red/yellow​red1​121.7 ohm​red/yellow​red2​117 ohm​green/yellow​green1​0.2 ohm​green/yellow​green2​0.2 ohm​green​green​0.1 ohm​
   
  Just to be sure the problem isn't your multimeter. Do you get reasonable values if you check an voltage at an outlet, battery? A resister?


----------



## graematter

My DMM is getting 2.2V on a AAA and 150V at an outlet. It must be faulty... correct? I'll go buy a new multimeter and get back to you. Thank you for all of this help. I'll be back soon. 
   
   
  Edit: The ohm portion of the multimeter seems to be working though. And when I measure the transformer I get very similar values to you. Could it be that the voltage portion of my multimeter is simply on the fritz?


----------



## balderon

I would suspect a defective multimeter. There are different circuits to measure ac, dc voltages, and resistance. It's possible to have a problem on the voltage side.


----------



## holland

Yeah, get a new DMM.
   
  It almost sounds like it was reading peaks instead of rms for AC, but the battery test was all out of whack as DC has no peak or rms readings.


----------



## graematter

I purchased a new DMM. I am now reading 6.51V for the heaters. 330V for the rectifier. And adjusted the B+ to 250v (it was at 203v). 281v at pins 1 and 7. The amp sounds great. SO sorry for all of the confusion, I feel ridiculous. But the C1 caps on the channel boards are still a bit puffed up. Should I be concerned?


----------



## herro

Does anyone know of any switches similar to the Bulgin ones (http://ca.mouser.com/Electromechanical/Switches/_/N-5g2h?Keyword=Bulgin&No=25&FS=True) in black/led or gold? I'm currently looking at the MPI002 (white led ring) but mouser nor digikey has them in stock.
   
  EDIT: found these: http://www.frozencpu.com/cat/l3/g44/c341/s875/list/p1/DIYMod_Parts-22mm_Bulgin_Style_Switches-22mm-Latching_Bulgin_Style_Switches-Page1.html
   
  I doesn't look like they are real Bulgins but nearly 1/3rd the price and have black housing, too. The site also has some rocker switches as well.


----------



## holland

Quote: 





graematter said:


> I purchased a new DMM. I am now reading 6.51V for the heaters. 330V for the rectifier. And adjusted the B+ to 250v (it was at 203v). 281v at pins 1 and 7. The amp sounds great. SO sorry for all of the confusion, I feel ridiculous. But the C1 caps on the channel boards are still a bit puffed up. Should I be concerned?


 

 That's great.
   
  Yes, they should be flat.  Pictures would help though, and heat is no good.  If the caps are puffing from heat, that's no good, and means you need to vent really bad.  I have all my tubes above the case.


----------



## holland

Quote: 





herro said:


> Does anyone know of any switches similar to the Bulgin ones (http://ca.mouser.com/Electromechanical/Switches/_/N-5g2h?Keyword=Bulgin&No=25&FS=True) in black/led or gold? I'm currently looking at the MPI002 (white led ring) but mouser nor digikey has them in stock.
> 
> EDIT: found these: http://www.frozencpu.com/cat/l3/g44/c341/s875/list/p1/DIYMod_Parts-22mm_Bulgin_Style_Switches-22mm-Latching_Bulgin_Style_Switches-Page1.html
> 
> I doesn't look like they are real Bulgins but nearly 1/3rd the price and have black housing, too. The site also has some rocker switches as well.


 


  I use these.
  http://cgi.ebay.com/1-Locking-illuminated-DPDT-Light-Switch-110V-G22ZE-/300495849842?pt=LH_DefaultDomain_0&hash=item45f6f2c972


----------



## herro

I'm sort of leaning towards the hammond hwchas walnut enclosure again..sometimes I hate DIY because I can never decide how my presentation of my work should look like. I did a mockup of how everything could be configured inside to case with a 'symmetrical' display of the tubes. Of course I could get away with a much small enclosure if I didn't do this. the hifi2000 chassis has even -more- room than the hammond, now that I've laid it out (all to scale):
   



   
  Is the 2.78" internal height for the tubes enough if I decide on an all-internal build (and would the be okay with mostly wood)? I know the hifi2000 case is enough for a full internal build. With the setup in the mock-up above, Ill have -barely- enough room for a y2 dac to the left of the psu board, however I would be able to fit it by omitting the top left standoff on the left amp board.


----------



## holland

2.78 might be tight.  I'd go larger.  The tubes radiate quite a bit of heat, the transformer too.  I did the symmetric thing too, but lined it up with the front panel.  I flipped one board over so it was truly symmetric and air wired the tube socket.  Overall, it was very neat (IMO).


----------



## balderon

Quote: 





graematter said:


> I purchased a new DMM. I am now reading 6.51V for the heaters. 330V for the rectifier. And adjusted the B+ to 250v (it was at 203v). 281v at pins 1 and 7. The amp sounds great. SO sorry for all of the confusion, I feel ridiculous. But the C1 caps on the channel boards are still a bit puffed up. Should I be concerned?


 
   
  Good to hear progress being made! Any malformed component is always a concern. Did you verify C1 is installed with proper polarity and is the correct value (10uF 250v)? I would suggest measuring the voltage (referenced to the star ground) on each side of C1. The positive side should read ~125 vdc and the negative should be ~51vdc.


----------



## herro

What kind of switch/knob would i need for a good input selector? Looking for something I can get a matching knob for both the input selector and the volume pot.


----------



## jdkJake

http://www.goldpt.com/


----------



## herro

Thanks. looks really nice but a bit pricey..would cost over 80$ /w shipping. any other sources? Might consider it if i cannot find anything else i like.
  Quote: 





jdkjake said:


> http://www.goldpt.com/


----------



## jdkJake

There are 55,185 switches available from Mouser. I have a gut feel one will meet your needs in terms of price and performance.


----------



## herro

I'm not really sure what keyword/terminology I'm supposed to use to get exactly what I'm looking for?
   
  Quote: 





jdkjake said:


> There are 55,185 switches available from Mouser. I have a gut feel one will meet your needs in terms of price and performance.


----------



## ujamerstand

rotary switches are the type of switches you are looking for.  
http://ca.mouser.com/Electromechanical/Switches/Rotary-Switches/_/N-5g2i/


----------



## Fast3d

I bought the kit from Glass Jar. It came with 2x6922 and 2x6N6P tubes. Should I be replacing the 6N6P for a ECC99? or the better question is which is better?
   
  Thanks


----------



## Fast3d

I just found an error on Cavalli website. On this page http://www.cavalliaudio.com/bijou/main.php?page=wiring  The different wiring diagrams for ECC99 and 6N6P are different on that page, but when you click on the "Click to Enlarge" link they are both the same pic. Threw me off a bit. Both links point to the same page http://www.cavalliaudio.com/bijou/images/BijouBoardWiring.gif   :|


----------



## balderon

Quote: 





fast3d said:


> I bought the kit from Glass Jar. It came with 2x6922 and 2x6N6P tubes. Should I be replacing the 6N6P for a ECC99? or the better question is which is better?
> 
> Thanks


 

 Welcome to the group! Either tube has it merits and it is a personal preference which one you use. I personally like the sound signature of the ECC99. Others like the 6N6P. Initially I built the kit from Glass Jar using the stock parts. The Regal mod was the only update I applied when I stuffed the amp boards. Once everything was working I started adding tweaks and rolling different tubes. This way I know how the mod affects the sound signature.
   
  Quote: 





fast3d said:


> I just found an error on Cavalli website. On this page http://www.cavalliaudio.com/bijou/main.php?page=wiring  The different wiring diagrams for ECC99 and 6N6P are different on that page, but when you click on the "Click to Enlarge" link they are both the same pic. Threw me off a bit. Both links point to the same page http://www.cavalliaudio.com/bijou/images/BijouBoardWiring.gif   :|


 

 If you click on the image the correct picture comes up. You could send a message to runeight (Alex Cavalli) about the link problem.


----------



## Fast3d

Great thanks. I'll PM Runeight


----------



## holland

@herro, i hope you end up top mounting the tubes.  it's not viable in a sealed enclosure, imo.
   
  @Fast3D, I use Sovtek 6H30 and 6N6Pi in mine.  I like it.  I'm not a real fan of the 6922.  YMMV.  It should be easy to switch tubes around, so roll it a bit.  Socket the resistors that need to change (R2) with SIP pin sockets.


----------



## Fast3d

Do you have a mouser part number for the SIP socket? Also is the 6N6P the same as 6N6Pi?


----------



## holland

575-113120
   
  This is one of them, I buy different kinds and can't remember what I use.  Whatever works.  You have to cut it, I take the wire cutters and snip them and then solder them in the through-hole.


----------



## herro

Recommended I use any specific type of solder for this? Would appreciate mention of any other thing I've overlooked or suggestions for components welcome (mouser numbers appreciated too if applicable). I was going to confirm my mouser order now, but I'll wait for a few posts if anyone can be of help.


----------



## balderon

I am partial to Cardas Quad Eutectic Silver Solder. An entire roll is expensive but you can purchase small lengths on fleabay. If I recall correctly I used much less than 20 foot when I built a Bijou. It wouldn't hurt to have extra for other projects.


----------



## holland

i use kester.  any old solder will be fine.


----------



## balderon

Quote: 





holland said:


> i use kester.  any old solder will be fine.


 
   
  Yeah any solder will work but IMO an eutectic alloy solder is preferred no matter who makes it.


----------



## herro

Thanks guys. I went ahead and ordered 20 ft from ebay for ~$5 shipped (CARDAS Quad Eutectic Silver Solder).


----------



## holland

Quote: 





balderon said:


> Yeah any solder will work but IMO an eutectic alloy solder is preferred no matter who makes it.


 

 Yep.  I use Kester 44 63/37 .020 which is a good diameter for SMD as well.  I bought a large lot (~10lbs or so), which will probably last me a few decades.


----------



## walangalam

Finally fired up my Bijou  
	

	
	
		
		

		
			




   
  Its quite disconcerting for a tube noob like me to see 0.0 in the B+ line when I flicked the switch, and no glow in the PS tube.  So I panicked and powered down, must be the heater lines.  Nope.  Must be the tubes not seated.  Nope.
   
  Turned it on again, still zero.  As I stood there thinking, I noticed that the reading slowly started going up -- 10, 15 50, 100, 240.  Phhwew!!!  
   
  Its just the tubes needing time to heat up -- about 30 seconds or so.  This info was NOTin the 240 pages of this thread.
   
  So I finished up the wiring and fired it up, after a few hours idling I put in some cheap test phones and MP3 source.
   
  WOW.
   
  Even completely stock (except for the Rubycon photo caps from pabbi1 -- thanks), the magic is there, and with cheap phones, and a small mp3 player.  I couldnt beleive those phones could sound so well. These same phones on my dynalo sound like crap.


----------



## pabbi1

Be sure to listen to something classical recorded well in a good hall - that is where the Bijou will really show you something special... and spatial.
   
  Yes, waiting for the rectifier tube to warm up is a bit different...


----------



## walangalam

What's wrong with this picture?  Hint:  the amp is Dead.


----------



## balderon

First off the resistor on the PS HV outputs should not be installed. This is used to adjust the power supply without the amp boards.
  It's difficult to see how the wires on the transformer are connected to the PS. Are the yellow and white wires on the proper terminals?
  What is the B+ voltage with the amp boards (without the resistor)?
  Are ALL the tubes lighting up?


----------



## walangalam

The resistor is there intentionally to discharge the caps faster -- it only adds 2.5ma.  but nope, its  not that.  look carefully and you'll see...  
	

	
	
		
		

		
		
	


	



   
  Oh and I disconnected the transformer to see if its still functional -- it is. Thankfully.


----------



## balderon

^^ I see you took off the plastic on C1 and looks a little unhappy ....


----------



## walangalam

You got it.
   
  The amp has been running for about 4 hours, I left and came back 1 1/2 hours later to the smell of burnt electronics.
   
  The big cap (C1) blew.  The fuse blew, probably saving a lot of parts.
   
  Tested the transformer, its fine.  Tested the PS board after removing C1, its also fine -- giving me a B+ of 255 V.
   
  Next would be to see if the amp boards are damaged.
   
  I got the kit from Glass Jar, so its probably just a bad electrolytic.  Now, I'm also suspecting the other 2 big caps.  I wonder why it blew????


----------



## herro

Are there any equivalent/better transformers I could use for the build before I put in my mouser order? The 270dax is ~$70 at mouser (pointless sourcing it from somewhere else as I'm doing a mouser order already, and a cheaper price + shipping would add up to the $70 anyway.). What's this toroidal one?


----------



## walangalam

its this one: http://www.antekinc.com/details.php?p=47
   
  its 39.50 shipped.
   
  In my stock build, it gives 250 volts just barely, with only 5 volts headroom, and with 120 volts mains.
   
  If you do the regal mod, you might have to dial it down to 240volts.
   
  But its a bigger transformer, so you roll the tubes you like.


----------



## holland

Antek rates their transformers differently.  Other manufacturers rate their voltage loaded.  Antek rates theirs unloaded, and as such the voltage drops below what you expect when you put the load on.  This way they can claim higher voltage at a certain VA.  The reality is it's a lower voltage, at specific current ratings.  It's more of a 235V transformer than 260V.
   
  For Antek, you need to read the datasheet, and often times you need to up-spec the xformer.  That is you will need to go more current or more voltage.
   
  I use the RCore, r80-36 (i think that's the part).  I have no problems with it.  You may need to spend a bit more time, checking phase on the heater windings.  I parallel'd all the windings.  It's easy to do, once you tie the center taps together, phase is simple.


----------



## flao38

what a project, well done


----------



## walangalam

Here are voltages from my Antek transformer:
   
  Rating:  250v 200ma X2, 6.3V 3A X2   100VA
   
  with PS only:  265VAC, 6.6VAC
  with PS + Amps:  260VAC, 6.34VAC
   
  So it looks like its rated correctly, at least on this unit.  And its cool to the touch too.
   
   
  Quote: 





holland said:


> Antek rates their transformers differently.  Other manufacturers rate their voltage loaded.  Antek rates theirs unloaded, and as such the voltage drops below what you expect when you put the load on.  This way they can claim higher voltage at a certain VA.  The reality is it's a lower voltage, at specific current ratings.  It's more of a 235V transformer than 260V.


----------



## holland

Perhaps they changed.
   
  It also doesn't match the spec sheet for the xformer, which is odd as their other transformers matched it quite well (read the EHHA rev A thread for more recent measurements of the Antek xformers) and it matches my Antek experiences from years ago.
   
  Either way, tread carefully and read the spec sheet as it pertains to Antek transformers in particular.
   
http://www.antekinc.com/pdf/AN-1T250.pdf

   
  Note the unloaded voltage of 257VAC and the loaded voltage of 237VAC.  Of course the Bijou draws considerably less current than 500mA.
   
  It would be great if they start to rate as other manufacturers do.  I still use them either way, and would normally upspec.  Your measurements, however, could mean a crapshoot instead of a dependable way to deal with Antek.
   
  I'd measure the Antek 0532 that I'm using for my EHHA build, but I bought it about 2 years ago, so it's probably the older spec (32V unloaded, 30V loaded).


----------



## herro

What's the best way to mount tubes externally without using any screws through the top of my enclosure? Standoffs on the PCBs?


----------



## balderon

I mounted the components on the reverse side of the amp boards. Using standoffs allows the tube sockets to extend through the top panel without screws. The only concern was the MOSFET heat sinks on the PS. There is a fair amount of heat to dissipate and the PS board will heat up significantly if the heat sinks are mounted on the reverse side. Give it some thought. There are numerous ways to solve the PS heat dissipation issue without screws in the top.


----------



## herro

Yeah, I'm getting my kit tomorrow so just currently brainstorming how I'm going to achieve certain tasks. I've decided to go with the HWCHAS from Hammond, I like the look. Not sure if I want the black or natural aluminium finish for the top though. Since the bottom plate is sold separately, I'll get a bottom plate of the opposite colour from the top plate, so I can swap them if I decide, or even get the natural one anodised.
   
  Mouser is fresh out, however digikey has them for ~$108 shipped to me in Canada (a bit pricey, however I do not have the tools or want to bother with finding someone to make me something similar). This does not include the bottom panel which I found from a UK dealer for $12/$20 for natural/black respectively (digikey, mouser, newark etc. had absolutely nothing without me waiting for at least two months or more). The same UK dealer also sells the HWCHAS enclosures for $82, but shipping the heavy item might be a little pricey so I contacted them for a quote.
   
*Should I just go with the 270DAX then? I don't plan on doing any major modifications, but I may want to try some better tubes in the future. *


----------



## holland

Quote: 





herro said:


> *Should I just go with the 270DAX then? I don't plan on doing any major modifications, but I may want to try some better tubes in the future. *


 
   
  Perhaps a look at the BOM will help you decide.


----------



## pabbi1

370DAX is a better choice, and Angela has them at a good price... not sure about shipping to your location.
   
  I can recommend the 6n6p/6n1p for reasonably priced tubes, and might also look into the 6n23p-ev. In Russian tubes, always at least consider the 'ev' versions - better QC and spec compliance. And definitely socket the R2 cathode resistor so you can roll the tubes. If I had another shot at Bijou, the 6h30 would be my first stop, since I went 6n1p/6n6p... this is NOT a universal recommendation. 
   
  Anyone used the 6h30DR? Just curious.


----------



## holland

Quote: 





> Originally Posted by *pabbi1* /img/forum/go_quote.gif
> 
> If I had another shot at Bijou, the 6h30 would be my first stop, since I went 6n1p/6n6p... this is NOT a universal recommendation.
> 
> Anyone used the 6h30DR? Just curious.


 
   
  I don't use the DR, but I do use Sovtek 6H30 as the gain and 6N6Pi as the driver.  I like the 6H30 over the 6922 by a good margin.  It helps that the overall gain is lower too.


----------



## regal

Quote: 





holland said:


> Quote:
> 
> 
> 
> ...


 


 The 6n6p is a great driver tube for this amp,  they are very undervalued in my opinion.     For the gain it would be worth trying something other than the 6DJ8 as the only ones that sound great are expensive holland tubes from the 60's and you have to buy several to find a good pair,  so I would focus on substituting those.


----------



## regal

Quote: 





walangalam said:


> You got it.
> 
> The amp has been running for about 4 hours, I left and came back 1 1/2 hours later to the smell of burnt electronics.
> 
> ...


 


 Sure you got the polarity on the caps  right?   Its odd that your B+ is 255V and these blew up,  could it be heat?


----------



## walangalam

Yeah, I double triple checked my polarities before first power on.  I'm thinking now that the caps probably needed reforming.  After fixing C1, I noted that C4 was almost hot to the touch, and C5 and C6 were warm after about 2 hours.  So I decided just to replace all the caps just to have peace of mind.


----------



## adamus

something must be wrong... there is no chance that they all needed reforming...
   
  Check your mains wiring, check you voltage ratings, check the input voltage. Something must be wrong.


----------



## walangalam

When I get the new caps, I'll check again.  There is definitely something weird going on.  Of the original caps, I only have C6 and C5 in there.  Both are warm after a few hours.  Then the weirdness sets in.I initially get 313VDC at R8, then when the caps are warm, it dips to 303VDC.  I check the AC from the transformer, its 260VAC, did not change at all.  Then it climbs back to 313VDC.  I move the volume to max, with a low impedance phone, it climbs to 320VDC, check transformer again its still pegged at 260VAC!  
	

	
	
		
		

		
			




   
  If this behavior persists with the new caps, I might get a new EZ81.  It might have been damaged when the cap blew and tripped the fuse, which is a 3A fast blow.


----------



## adamus

hmmm.. i suggest checking out the voltages cafefully against Cavallis's troubleshooting diagram. Somthing is going on that is probably not cap related. Could you still adjust the voltage (a good indication the fet is still intact)?


----------



## walangalam

yes, I could adjust the voltage just fine.  But the weirdness is happening before the regulator.


----------



## runeight

If there is a large AC ripple current on the filter caps this could also damage them as it will cause them to heat up. If you have a scope just look at the voltage at the first cap to see what the AC component is.
   
  The only other thing that I can think of is that the caps (as already mentioned) are in backwards.


----------



## walangalam

well the caps arrived (all panasonics) and I installed them around lunchtime.  More stable voltages and about 3-4 volts higher too at 317 volts at the first cap.  The amp has been burning in since then.  Even at full volume I dont see the 320volt peak anymore. 
   
  I also found out why its the voltage sometimes dips -- its the microwave plugged into the same circuit in the kitchen.  I was heating up water and I just happened to measure, and I just caught it at 308vdc at the first cap and 253VAC at the tranny.  This sort of thing could drive anybody crazy.
	

	
	
		
		

		
		
	


	



   
  Now if could only get my case I could finish this project by new years -- its out of stock and the seller is ignoring my request for refund.  Oh well, at least I could start listening in earnest.
	

	
	
		
		

		
		
	


	




  Thanks runeight for this my first tubey project!


----------



## yiancar

I am close to finishing my balance bijou, but it seams i cant get everything to fit in a single case. Would it be better to have just the transformers in a separate enclosure or put the whole psu?


----------



## herro

Is it worth getting the 370dax over the 270 for ~$18 more?


Might actually consider it as I am living in N. America now but may be moving back to UK in the next year or so.


----------



## walangalam

in that case yes.


----------



## runeight

Quote: 





walangalam said:


> Thanks runeight for this my first tubey project!


 


 You're welcome.


----------



## herro

I went with the 370DAX. Finally got around to buying _everything_ (except knobs.... looking for black ones in similar style to the ones the bottom of this page, but closer to 40 mm so they are a bit more prominent on the chassis). Going to get started populating the boards over the next day or two. I expect to get the rest of my accessories within three days and the enclosure in under two weeks!


----------



## mikelikespie

Hi, pretty new to the DIY stuff here.  Anyways, I am almost finished with my bijou build.  Just waiting on a few jacks and the transformer and it should be good to go.  I've been thinking about an enclosure for it and I have a few q.
   
  Ideally, I'd like the tubes (at least on the amp part) to protrude through the top of the enclosure.would soldering the larger caps to the other side of the PCB to accomplish this be a bad idea, or are there easier solutions?  I saw one photo of somebody putting the tube sockets on the other side, but that looked like it required some extra custom wiring, which I'd rather not do, and also I don't think I want the entire tube sticking out.
   
  As far as cooling is concerned, which parts heat up the most that I should account for in the enclosure design?
   
  Also, does anybody know a good site that sells _small_ quantities of interesting metal meshes?
   
   
  Thanks,
  Mike


----------



## BebopMcJiggy

Small parts on amazon actually has quite a variety of metal meshes in 12x12 or 24x12 sheets (maybe bigger?) but they're pretty well priced like 10 to 30$ maybe depending on material / specifications and can get super saver shipping...
   
  I dunno if brass / stainless steel / aluminum and the like are not interesting enough though ;O.


----------



## walangalam

caps underneath is how its usually done.
  
  Quote: 





mikelikespie said:


> would soldering the larger caps to the other side of the PCB to accomplish this be a bad idea, or are there easier solutions?


----------



## funch

Can a log pot be used for the NFB, or must it be linear?


----------



## zzffnn

Hi Bijou experts, please kindly help me with the hum that my balanced Bijou consistently produces in one channel.
     
  I recently bought a balanced Bijou for my 600 ohm Beyer T1. The combo was very lovely (better than my AMB M3/Sigma11) until I did some thing stupid.

 I took off the transformer cover and tighten (I think no excessive tightening) some screws inside the amp. Then I have big hum (hmm kind of sound) consistently in one channel via the Beyer T1. Putting back the transformer cover and un-tightened the screws did not reduce the hum. My seller is very kind and nice and helping me to trouble shoot with photos. I am putting a post here just to get more help, as I think the problem may not be solved easily.

 So I tried the following things with no luck:
 1) burnt-in, warmed up the amp
 2) disconnected any input to the amp, just listened to the amp with headphone w/o input
 2) switched all tubes between the two sets of amp and power boards (as this is a balanced tube amp), still had same hum from same side (I am using the single end output btw).
 4) both of my headphones got the same hum from the same channel (600 ohm T1 and 80 ohm DT770).
 5) The hum does not change with volume adjusting.
 6) used a different outlet.
 7) used a two prong "cheater" outlet
 8) turned all the light dimmer to off all over my office (it was an old residential house, some dimmer are not working).
 9) Used chopsticks to push/tap tubes slightly when the amp is running. And slight pushed PCB boards. I did not hear much changes when I did these procedures.
 10)checked about wires and connections (note that I have no DIY or EE skills to do this extensively though).

 Big photos will high zoom from inside of the amp can be found in my photo album here:
 http://www.head-fi.org/gallery/image/view/id/81198/user_id/126562
   
  Please kindly advise me. keep in mind that I have multi-meter with me but can not solder and have almost no electrical or DIY skills.

 Since I swapped tubes between the 2 same sets of amp and power boards (this is a balanced tube amp), whatever noise from tubes should shift as well, correct?
 Unless  the join between PCB and certain tube is "cold"? I think I did not tighten the screw excessively to cause this........but I do not know.....
  
  Thanks a lot for reading.


----------



## holland

Quote: 





funch said:


> Can a log pot be used for the NFB, or must it be linear?


 


  You can use a log pot, but the amount of NFB won't exactly be easy to control since the resistance is now logarithmic instead of linear.


  Quote: 





> Originally Posted by *zzffnn* /img/forum/go_quote.gif
> 
> Please kindly advise me. keep in mind that I have multi-meter with me but can not solder and have almost no electrical or DIY skills.


 
   





   
  your pictures are too small.  bigger and high res.


----------



## jdkJake

funch said:


> Can a log pot be used for the NFB, or must it be linear?





 


It would certainly give you more adjustment resolution in the middle of the pot while sacrificing resolution at the ends.

Where do you normally set it at?


----------



## funch

I like to experiment around with it, but usually leave it 'off' for my HD600's. I guess I'll just leave the default pot in there.
  The only decent linear that I can find is to get a 'bare' Goldpoint SA and set it up linear. Thanks, guys, for your input.


----------



## zzffnn

Quote: 





holland said:


> You can use a log pot, but the amount of NFB won't exactly be easy to control since the resistance is now logarithmic instead of linear.
> 
> 
> 
> ...


 


  Please click on "URL to inbed", once the photo loads, please click on the displayed photo once more, that will give you big photo with high res. Thanks


----------



## mikelikespie

So I got everything working (or so I though) and it sounds amazing.  However, I started to see a little smoke.  My c4 on the PS board became extremely hot. it seems.  The top is just a touch round too.
   
  So 2 questions:
   
  Did I ruin the cap?  Should I replace it?
   
  How do I debug this problem?  Should I look for a short or something?  I'm pretty sure I have it in in the right direction, and there are no obvious shorts on the board.
   



   
  Cap on the right is C4
   
  Thanks,
  Mike


----------



## walangalam

You should replace it.  It might blow, just like it did in my build -- see post 3718.


----------



## balderon

Quote: 





funch said:


> I like to experiment around with it, but usually leave it 'off' for my HD600's. I guess I'll just leave the default pot in there.
> The only decent linear that I can find is to get a 'bare' Goldpoint SA and set it up linear. Thanks, guys, for your input.


 
   
  Hi Allen --
   
  This is what I used in my build. http://cgi.ebay.com/ALPS-250K-DUAL-LINEAR-CONTROL-POT-/150510750996?pt=LH_DefaultDomain_0&hash=item230b23cd14. It may be a little pricey but I have had no problems with it.


----------



## balderon

Quote: 





walangalam said:


> You should replace it.  It might blow, just like it did in my build -- see post 3718.


 

 Agreed. I find it very odd why there have been so many problems with these caps recently. Has anyone talked with Jeff Rossel @ Glass Jar Audio and given him a heads up?


----------



## mikelikespie

Quote: 





walangalam said:


> You should replace it.  It might blow, just like it did in my build -- see post 3718.


 


  Oh yeah, that doesn't look good.  I think I will remove it from my PS asap.  Would it be a bad idea to use the amp w/o the extra cap?  I ordered some replacements, but it will be a week or two.  I wonder if I could use a 450v 200 uf for the time being instead?


----------



## balderon

Quote: 





mikelikespie said:


> Quote:
> 
> 
> 
> ...


 

 IMO it is undesirable to use the amp without the proper RC filtering. If you have two 200uF@450v, you could parallel them together and get close enough.


----------



## funch

Quote: 





balderon said:


> Hi Allen --
> 
> This is what I used in my build. http://cgi.ebay.com/ALPS-250K-DUAL-LINEAR-CONTROL-POT-/150510750996?pt=LH_DefaultDomain_0&hash=item230b23cd14. It may be a little pricey but I have had no problems with it.


 


 Jeff,
   
  Thanks for the heads-up.


----------



## yiancar

If lets say i want to pass the heaters (ac) and the 250v(dc) through a single cable from my psu to amp, do i need a special cable with some twisted pairs and some not?
  In addition, will the R80 transformer be stressed too much if i put around 6.5 A in its 6.3 taps? (I am planning to use 4 6h30 and 4 ecc99)


----------



## holland

Quote: 





yiancar said:


> If lets say i want to pass the heaters (ac) and the 250v(dc) through a single cable from my psu to amp, do i need a special cable with some twisted pairs and some not?
> In addition, will the R80 transformer be stressed too much if i put around 6.5 A in its 6.3 taps? (I am planning to use 4 6h30 and 4 ecc99)


 
   
  I, personally, wouldn't use a single cable, but multiple cables.  I would add extra filtering in the primary amp case for the HVDC.
   
  Read the specs on the R80 transformer.  You're over.  You're also over on the HV.  You are building a balanced amp.  Double the PSU requirements.


----------



## yiancar

I just realized that. Ive bought a 6.3V 3A transformer to help me power the heaters. However the R80 cant handle the HV of both psu ?
  Btw with more filtering you mean use more caps at the end?


----------



## holland

It probably can, R80-36 right?  I'm not sure it can if you do the Regal mods though.  You'll likely need to PS boards though.  I'm not sure one can power 4 boards.  Add that to your heater requirements too.
   
  FWIW, I have the R80-36 in 2 channel configuration.  With Regal mods, I need to regulate to 245V after about an hour of warming up.  It starts off high, but then starts to sag.  I need to take a look at it again, as it's been over a year since I opened it up.


----------



## yiancar

I have 2 psu boards. I am thinking of buying a  second R80-36( yes that he one i already have) in order to just be sure for both the heaters and the hv. Also I didnt made the Ragel mod as it was too difficult to find the relatively high current resistors. Could you measure how many amps yous psu needs from the HV?


----------



## mikelikespie

While waiting for the replacement caps, I've been fiddling around with enclosure design.
   
  I was going to build a box, but I found this one I had that fits the components quite perfectly (perhaps a bit snug).
   
  I'm going to have the tubes protrude through the lid.  I have a socket saver coming for the EZ88 so that won't be an issue.
   
  For the transformer, am I going to want to have that protrude through the top, or will cutting some holes in the box be good enough?
   
  Also, should I be concerned about the amp boards being so close to the PS board as far as hum and the likes go?
   
  Thanks again.
  -Mike


----------



## yiancar

In may cause ham. If you cannot increase the distance, try a metal plate between them.
  Also have you put a metal "shield" on the bottom? the heater wiring will also hum if you didn't


----------



## holland

Quote: 





yiancar said:


> Could you measure how many amps yous psu needs from the HV?


 
   
  I will try to, but it's a bit hard for me now.  Everything is cased up and IIRC, the PSU section was a tight fit.  The easier solution would be to find someone who has done a balanced build.  I think Pabbi1 built a balanced version with a single 270DAX, but no regal mods, AFAIK.


----------



## yiancar

well now it doesn't matter , I ordered a second transformer just to be sure . Amphead warned me that if the transformer overloads it can dramatically heat up and even catch fire, so I don't leave it to luck. Thankyou holland for the info, I'll post pics and impressions as soon as i finish


----------



## mikelikespie

Quote: 





yiancar said:


> In may cause ham. If you cannot increase the distance, try a metal plate between them.
> Also have you put a metal "shield" on the bottom? the heater wiring will also hum if you didn't


 
   
  Nope, have not yet.  I will do it for sure.  Will any metal plate do?  Is it worthwhile looking into shielding for the sides as well?  Avoiding GSM noises would be preferable if that helps.
   
  Edit:
   
  Should I run the heater wiring underneath the metal plates where possible?


----------



## holland

Quote: 





mikelikespie said:


> Nope, have not yet.  I will do it for sure.  Will any metal plate do?  Is it worthwhile looking into shielding for the sides as well?  Avoiding GSM noises would be preferable if that helps.
> 
> Edit:
> 
> Should I run the heater wiring underneath the metal plates where possible?


 


  It wouldn't hurt.  Nothing beats distance and physical barriers.  Mind how you stacked your items.  The crossing points will be the terminal blocks.  You have the heater of one, right next to the output of the other.  Distance will help you get a quiet amp.


----------



## particleman14

if anyone wants I have 4 rubycon 410uf 300v caps for C5  and some panasonic polyester and shanling mkp 1ufs for C6 position on the bijou.  I swapped mine out for some motor run caps so these are just sitting., just pm me and I'll ship them to you.  courtesy of pabbi1.


----------



## Coupe

3 cheers for pabbi!


----------



## hakko

Hi! I had some plans to do this build but I have a major question at least for me.. Can I exchange the rectifi er tube by diodes without making hum? I question this coz my father are an old technician and he said that in his time they often replace this rectifier tubes by diodes and he said that's no noise was heard from radios,tvs etc.. Btw some one tested with diodes on this build on pw supply?


----------



## holland

i don't think hum is an issue.
   
  the difference is that diodes come on immediately.  you may want to read the design pages.  the soft start of the tube rectifier was a desired effect.  i don't think it'll be a problem, personally.
   
  I haven't experimented with it, but have thought of it, as it's a lighter load on the PS.


----------



## hakko

I thought that this problem of delay waiting the heaters top up their temperature are only necessary in tubes that work with h.v like transmiter tubes and other especial tubes but who knows...


----------



## holland

that's my understanding, but i don't know for sure.  i think it should be safe for the tubes.  i don't think it's an issue, particularly if you are using generally available tubes and not some ecclectic $1000/pair set...in which case, it's your money, so if you feel confident, then go for it.


----------



## diego

Diodes won´t produce hum but they might produce some high frequency noise depending on the design and the diodes. You would loose the soft start feature but the bass would be a little faster and harder. The voltage would be higher and the regulator would dissipate more heat keeping it at 250vdc (assuming you do it using the Bijou PS) . Finally, the heater voltage might increase due to a lighter load.
   
  If I were going to experiment with a SS supply on the Bijou, I would use a PS designed for SS rectification and I also would use a regulated dc heater supply. However, you would have to use a different transformer.


----------



## hakko

I see.. But why the voltage of the heater will get high since the transformer will leave 6.3 AC on heater line isn't? Btw I'am thinking to use the same  pw supply topology full wave but without rectifier bridge only changing the Ez80/1 with two silicon diodes(this tubes are aslo called diodes hehe).. Btw I'am E.E student so I can manage  problems with they happen


----------



## holland

Quote: 





hakko said:


> I see.. But why the voltage of the heater will get high since the transformer will leave 6.3 AC on heater line isn't? Btw I'am thinking to use the same  pw supply topology full wave but without rectifier bridge only changing the Ez80/1 with two silicon diodes(this tubes are aslo called diodes hehe).. Btw I'am E.E student so I can manage  problems with they happen


 

 transformer ratings are with load.  so if you don't have load, the voltage won't come down and it'll be higher up.  pull up a transformer datasheet and you will see loaded and unloaded voltages.
   
  it's not a big deal.  a couple of inline resistors and it's not a problem.  you need to do that anyway, regardless, to ensure your heater voltages are within spec.
   
  There's more voltage loss in a tube rectifier than a diode.  you can always increase the resistor in the CRC filter or add another RC stage, so again, not a problem.  Work with it and you'll be fine.


----------



## hakko

I will just remove the EZ80 the other tubes will be loaded with AC by the transformer so I think it will be not a big voltage difference isn't?


----------



## holland

Quote: 





hakko said:


> I will just remove the EZ80 the other tubes will be loaded with AC by the transformer so I think it will be not a big voltage difference isn't?


 


  It will rise a good bit as the EZ81 is a 1A load and the EZ80 is a .6A load.  You need to ensure you are within tolerances.  Like I said, measure it, and put a couple of resistors inline to drop it down.
   
  Load rating is based on the amount of current draw.


----------



## hakko

Ok! When I get the transformer I will do the messures and the necessary calcs


----------



## diego

That's right, when you take out the tube rectifier the transformer will have a significantly lower load. If you use a 270DAX the heaters will come up significantly. On the other hand, if you use the 370DAX which has better regulation the increase will be smaller. As Holland says, you could fix it with resistors.
   
  If you use diodes in the Bijou PS, try to use ultra fast, soft recovery diodes to avoid the noise.
   
  Personally, I think I would build it as it was designed.


----------



## diego

I also highly recommend  using the 370DAX transformer. The 200 series tend to run hotter.


----------



## holland

sounds good.  just get a resistor with the necessary wattage rating.  it's going to be a power resistor, because you could be putting upwards of 3-4A through it.


----------



## balderon

The slow start up of the B+ is believed to be easier on the tubes.
   
  EDIT: Good discussion at http://www.diyaudio.com/forums/tubes-valves/179760-correct-path-diodes-rectifier-tube.html


----------



## walangalam

Finally done!!!
   

   
  More pics at the post pics of your build thread.


----------



## gabriel-dan

Beautiful job Walangalam, well done!


----------



## balderon

Quote: 





walangalam said:


> Finally done!!!
> 
> 
> 
> More pics at the post pics of your build thread.


 
   
  Very nice build walangalam! What did you end up using for the socket covers?


----------



## bhjazz

Wow.  That is a beautiful build.  Super clean, super professional looking.  Well done!
  
  Quote: 





walangalam said:


> Finally done!!!
> 
> 
> 
> More pics at the post pics of your build thread.


----------



## walangalam

Thanks.  I enjoyed planning it.  Not so much drilling, though.  Those holes are a pain to line up.
  
  The aluminum  covers  I found in my local electronics shop.  Those are actually aluminum spacers from a hard drive -- I would guess from the platters.
  Quote: 





> Originally Posted by *balderon* /img/forum/go_quote.gif
> 
> Very nice build walangalam! What did you end up using for the socket covers?


----------



## Coupe

Quote: 





walangalam said:


> Finally done!!!
> 
> 
> 
> More pics at the post pics of your build thread.


 


  That is amazing!  What case is that!  I would love to model my case after that, with your permission!  Is there proper ventilation?


----------



## walangalam

Quote: 





> That is amazing!  What case is that!  I would love to model my case after that, with your permission!  Is there proper ventilation?


 


  no problem  
	

	
	
		
		

		
			





.  Its here: http://www.hllyaudio.com/diy-parts/headphone-amplifier-aluminium-chassis-01.html.  It took a long time to receive though (was out of stock when I ordered, but the website didnt say that), so you should be patient.  You could also find it in ebay.
   
  The completely closed case did get very warm after a couple of hours, so I drilled 4   .25"  holes at the back panel, the reasoning being that the five tube holes will be the air outlet, with back panel holes as the air inlet.  The case is 3mm aluminum so its also acting as a large heatsink.  You could drill more holes up top, if youre worried about heat.  I didnt want to mar the look with holes, so I didnt.


----------



## eertelppa

Something I have been wondering after going through countless pages of this thread is what exactly are the meters some people have included in there build. A few builds I remember seeing that had two or so meters with needles that measure something...
   
  Thinking about making a nice wooden case out of walnut and making the sides have a nice metal mesh. Trying to draw up a few rudimentary sketches and look over the bom to see how much everything will cost.
   
  Also want to investigate further on the "regal mod" I keep reading about along with learning a lot of the acronyms. I assume PS and PSU are power supply and power supply unit, respectfully. Need to educate myself on the electronics more in depth as I did not fair well in my electrical engineering course I had to take. I would like to make a few upgrades to the build wherever possible but it seems the most common is a "370DX", IIRC, along with the choosing of tubes. Other components and supplies seem to not really have upgrades but more personal users preferences. Please correct me if I am wrong.
   
  Sorry for throwing so many questions out there. My current project is my new turntable, but I can already see this will be fast approaching.


----------



## holland

Quote: 





eertelppa said:


> Something I have been wondering after going through countless pages of this thread is what exactly are the meters some people have included in there build. A few builds I remember seeing that had two or so meters with needles that measure something...
> 
> Thinking about making a nice wooden case out of walnut and making the sides have a nice metal mesh. Trying to draw up a few rudimentary sketches and look over the bom to see how much everything will cost.
> 
> ...


 
   
start here
   
  I'm not sure what meters you are talking about.


----------



## jdkJake

eertelppa said:


> Something I have been wondering after going through countless pages of this thread is what exactly are the meters some people have included in there build. A few builds I remember seeing that had two or so meters with needles that measure something...





I think you are talking about the VU meters that some folks have used to great effect. They measure an indication of volume based upon output power at a particular resistance and frequency. In this application, they are more for show than practical use (unlike recording), but they sure look fine!


----------



## eertelppa

Yes I looked at some builds from Ferrari and others over the years and had to spend the last 30 minutes trying to find the photos I had ran across over the past few months.
   
  I do believe they were all VU meters. It seems also they are "always" on balanced systems? I am so green to all of this but I would assume so one could ensure the same output levels are being seen in both the left and right channels?
   
   
  Thanks for the link as well I will do some reading over the coming days. Also I want to familiarize myself with balanced systems versus non-balanced. This is something I will leave out of this thread and read elsewhere (I assume it boils down to a preference thing and also would require separate amps and headphones for a balanced system) Anyway thanks again for the advice. I love looking through this thread. Hopefully in the coming weeks more and more of it will make sense to me.
   
  Austin


----------



## Joefish

I built a Bijou recently using ecc99 and a Hammond 370DAX transformer, I am very pleased with the result although the transfomer does run warm.
   
  I stumbled accross this Lundahl ll1683 Mains Transformer recenly and looking at the specs I thought it would be good for regions that use 240/120v
   
http://www.lundahl.se/pdfs/datash/1683.pdf
   
  I havn't bought one yet but may do in the future. I would be interested in hearing your thoughts.
   
  Joe


----------



## Coupe

Hello,
   
    It's time to continue the build.  I am trying to find a suitable outlet power entry socket.  Do you guys have any recommendations?  Should I fuse the power before the transformer?  What rating should this fuse be?
   
  I am also looking for a cool power toggle switch.  Perhaps a white illumination ring with chrome style.  Where can I purchase this?
   
  Thank you!


----------



## balderon

The mains power should be fused and filtered. I like using an IEC inlet filter with a power switch. My Bijou works well with 1a fast acting fuse.


----------



## Coupe

Would this work?  A fuse/switch/power filter in one?


----------



## balderon

double post


----------



## balderon

Quote: 





coupe said:


> Would this work?  A fuse/switch/power filter in one?


 
   
  The IEC link you posted is not fused. Any IEC will work if it is rated for your mains voltage and current. You should allow some overhead for power-on surges. I prefer to pick an IEC rated at least 10A.


----------



## Coupe

So if the main switch is listed as 20 amps, I'll need a 20 amp rated IEC @ the bijou?


----------



## bcg27

20 amps seems like extreme overkill, considering that most household circuits are only 15 amps other than ones that are expected to have major appliances on them. Most of the IECs I have looked at are rated at 10 amps, which should be way more than enough for a headphone amp. However, this rating is just the maximum current that the connector can handle. You will most likely want to get one with a fuse with a much lower rating, such as 1-2 amps (slow blow, to avoid power spikes to burn out your fuse).


----------



## balderon

Quote: 





coupe said:


> So if the main switch is listed as 20 amps, I'll need a 20 amp rated IEC @ the bijou?


 

 The capacity of the power switch and IEC should be sized in proportion of the amount of current you expect to flow through the parts. The Bijou typically draws less than 1 amp continuous. My personal preference is to use higher rated components as long as it wouldn't break the bank. I decided to use a 5A IEC in my build.
   
  Quote: 





bcg27 said:


> 20 amps seems like extreme overkill, considering that most household circuits are only 15 amps other than ones that are expected to have major appliances on them. Most of the IECs I have looked at are rated at 10 amps, which should be way more than enough for a headphone amp. However, this rating is just the maximum current that the connector can handle. You will most likely want to get one with a fuse with a much lower rating, such as 1-2 amps (slow blow, to avoid power spikes to burn out your fuse).


 
   
  I disagree with using a slow blow fuse as the risk of severe damage is greater especially with HV circuits. I would rather have the power interrupted immediately rather than the problem persisting if something did go wrong. I use HXP ceramic fuses for that very reason.


----------



## V-DiV

I'm back!  I had my Bijou build well on its way a year ago.  Boards were completed (Regal's and Amphead's Mods, Sonicaps at C2 & C6, Rubicon at C5, DACT, auxiliary heater transformer for tube rolling).  All parts on hand (I think).  I was in the process of building my case.  Wasn't happy with the case.  My wife wasn't happy with the time I was spending on it.  The whole thing got put aside.  Now I've built a new, better case and I'm trying to remember everything about the stray bits and pieces as I try to put it all together.
   
  The question for today is - is navships' silver teflon wire rated for 600v?  I can't find an answer anywhere.
  I have some 20 AWG shielded silver teflon coax and 22 AWG silver teflon.
   
  Thanks,
  Vic


----------



## V-DiV

Hey Balderon, how does your Bijou compare to your maxxed WA6?  Which headphones does each sound best with?


----------



## balderon

Generally navships' silver _*"plated"*_ teflon wire is rated at 600v or higher.
   
  Look at the specs section at http://www.logwell.com/tech/shdwe/teflon_wire.html


----------



## V-DiV

Quote: 





balderon said:


> Generally navships' silver _*"plated"*_ teflon wire is rated at 600v or higher.
> 
> Look at the specs section at http://www.logwell.com/tech/shdwe/teflon_wire.html


 


  Awesome!  Thanks.


----------



## m461c14n

Hi all,
   
  Aftfer reading all this thread, I ordered PCB from Jeff, February last year, and finally finished my Bijou.
   
  I'm using Rikken and Shinkoh Resistor, 820uF BHC Aerovox C1 at PS, and BHC Aerovox 470uF at C5 Amp, bypass by Mundorf SO 1uF (C6).
  Regal Mod and running with No NFB, 
  have few question about this:
  -  if I don't use NFB, should I add Feedback resistor, I read somewhere in this thread that I should install 125k R?
  -  Should I change C5 (470uF) at Amp PCB with Film Cap (ie: 200uf Tubecap) instead of e'lyt, b'cos I don't get the sound that I want,
     I want it sound Dark/Mellow, thick Mid and good detail. Currently using Valvo EZ81, Mullard 6DJ8 A-frame and ECC99. and sound is not "majestic voice"
   
  Few pic of my build:
   

   

   
   

   
  Rgds,
  Anton


----------



## V-DiV

Quote: 





m461c14n said:


> -  Should I change C5 (470uF) at Amp PCB with Film Cap (ie: 200uf Tubecap) instead of e'lyt, b'cos I don't get the sound that I want,
> I want it sound Dark/Mellow, thick Mid and good detail. Currently using Valvo EZ81, Mullard 6DJ8 A-frame and ECC99. and sound is not "majestic voice"
> 
> Rgds,
> Anton


 

 Anton, if you use the Bijou only with high impedance headphones like HD 650 then you won't need as large a capacitor (470 uF) at C5.  I believe even 100 uF or so will be ok, if I remember past discussions (Holland gave the relevant math).  To give your Bijou a fair chance make sure that your source is also good.  In your profile you appear to only have iPod sources, so you rely on the iPod's DAC, regardless of how good your LOD is.  Also, make sure your music files are lossless, and hopefully well-recorded stuff.  
   
  I'll be interested to hear what you think of the sound difference if you replace the electrolytics with film capacitors.


----------



## walangalam

Quote: 





m461c14n said:


> Hi all,
> 
> 
> -  if I don't use NFB, should I add Feedback resistor, I read somewhere in this thread that I should install 125k R?


 
   
  If no nfb, dont connect the feedback pot, and change R1 to 300 ohm, as specified in the tweaks section.  There is no need for a feedback resistor and I dont recall reading that anywhere in this thread  -- could be wrong though, as this is a very long thread


----------



## V-DiV

Just lit up my PS for the first time.  Went without a hitch.  Started to glow immediately.  Adjusted to 250V no problem.  Ran PS for about 10 minutes.  Maybe this weekend another Bijou will make music!
   
  What gauge wire should be used to ground power receptacle, PS board, and amp boards to star ground?  Is navships' silver-coated teflon AWG 22 good?


----------



## V-DiV

Wired up the heaters.  Amp board tube heaters burning brightly!  Tomorrow, if I have the time, its wire up the input & output and then make some music.


----------



## Coupe

Grats man!
   
  Got some trouble.  Has anyone ordered their kit from Glass Jar?  Did it come with the hardware to mount the mosfet to the sink and mount the sinks to the PCB?


----------



## balderon

double post


----------



## balderon

Quote: 





v-div said:


> Wired up the heaters.  Amp board tube heaters burning brightly!  Tomorrow, if I have the time, its wire up the input & output and then make some music.


 
   
  I am surprised you could stop there and not go and wire up the audio signals!
   
   Quote:


coupe said:


> Grats man!
> 
> Got some trouble.  Has anyone ordered their kit from Glass Jar?  Did it come with the hardware to mount the mosfet to the sink and mount the sinks to the PCB?


 
   
  Long ago my kit came with a insulator+thermal compound, shoulder washer, and screw although I decided to go old school and use my own mica insulator and arctic silver 5. I soldered the pins on the heat sinks to the PCB pads.


----------



## Coupe

Quote: 





balderon said:


> Long ago my kit came with a insulator+thermal compound, shoulder washer, and screw although I decided to go old school and use my own mica insulator and arctic silver 5. I soldered the pins on the heat sinks to the PCB pads.


 


  My kit came with the shoulder washer and the thermal compound film, but I don't seem to have the bolt and nut to mount the Mosfet to the heatsinks.  Also, I don't have the bolts/standoffs/posts (what are they?) to mount the heatsink to the PCB.  I don't know what to do now...


----------



## holland

Quote: 





coupe said:


> Quote:
> 
> 
> 
> ...


 


  4-40 or M3 screw for the transistor mounting.  The heatsinks have pins pressed into them.  If you don't have pins, your heatsinks are the screw in type.  You need a self-tapping screw, to screw it into the heatsink and attach it to the PCB.
   
  get these at a hardware store.  I'm not sure what size, but think a 4-40 self-tapping screw would probably work.  Measure the holes in the heatsink and get a screw that has a smaller inner diameter than that.  The threads will dig into the heatsink and clamp it to the PCB, when you put the screw through the bottom of the PCB into the heatsink.


----------



## V-DiV

Quote: 





balderon said:


> Quote:
> 
> 
> 
> ...


 


  Wired up and singing - Now!  I still have to clean up some things, but it fired up and played on the first try.  Sounding good.  Nice sense of air even fed by an iPod.  I have a signal ground issue though.  I get a little buzz when I touch the volume or NFB knob.  I may upgrade the signal wire too.  I'll get some hours on it and then evaluate the sound with my DAC and best NFB settings.  But at least for now...
   
  Another Bijou Sings!


----------



## holland

nice job.  you need to ground the nfb pot, for the buzzing while touching issue.


----------



## V-DiV

Quote: 





holland said:


> nice job.  you need to ground the nfb pot, for the buzzing while touching issue.


 


  Thanks you Holland.  That did the trick.
   
  Voltage seems to be settling in nicely.  
   
  I'll post pictures when I get it finished up and ready to close.  I need to finish drilling a few holes for the top.  I'm waiting on new RCA input jacks before.  My original jacks are not insulated because I was going to mount them directly on wood with my first case.
   
  I need to get a pair of knobs.  Anybody have a favorite North American source.  I previously ordered some from Hong Kong and received the wrong ones, expensive shipping charges and all. 
   
  In the meantime I'm enjoying listening.
   
  Thanks Alex.


----------



## funch

Check out Goldpoint knobs, or the Kilo knobs at Digikey. Goldpoint even has a store on ebay.


----------



## balderon

A while ago I recall finding some threads discussing sources for knobs. It may be worthwhile to try the Head-Fi search engine.


----------



## V-DiV

Thanks.  I ordered a couple of Kilo knobs from Digi-Key (and threw in a transformer for a noodle DAC kit that I've had in a box for a while).  My Bijou is dead quiet at full volume at any NFB setting.  I forgot which NFB is max and which is minimum.  Which way maximizes the volume?


----------



## holland

Quote: 





v-div said:


> Thanks.  I ordered a couple of Kilo knobs from Digi-Key (and threw in a transformer for a noodle DAC kit that I've had in a box for a while).  My Bijou is dead quiet at full volume at any NFB setting.  I forgot which NFB is max and which is minimum.  Which way maximizes the volume?


 


  Depends on your wiring.  The least amount of NFB is the loudest.  On my wiring, and probably the standard wiring though I haven't checked, I set it so that minimum volume is the least amount of NFB, and hence the loudest.


----------



## V-DiV

Quote: 





holland said:


> Quote:
> 
> 
> 
> ...


 


  Thanks.  I had pretty well figured that that's the way it worked.  And I did have mine wired the way I thought, with minimum NFB at most counterclockwise rotation.
   
  I've ordered some 100 uF motor run oil caps for C6 per Regal.  I will most likely only be listening with HD 800s.  I originally planned the Bijou for my K701s, but they are probably going to go away now that the 800s are in the house.  I'm planning to order some 6H30's as well.


----------



## V-DiV

[size=medium]My Bijou is all cleaned up now.  Here are some pictures.
   
    - Regal's and Amphead's Mods
    - Sonicaps at C2 & C6
   - Rubicons (Thanks Pabbi) at C5 (waiting for motor run oil caps)
    - DACT stepped attenuator
    - auxiliary heater transformer for tube rolling (not connected yet)
    - shielded wiring for signal, heaters, grounds
   
  The amp is dead quiet at all NFB settings at max volume.  Sounds great too.
  My casework is not up to Holland/zkool standards, but the design is reasonably nice, I think.
  Thanks again to Alex, Regal, Pabbi, and all who helped out with my many questions.
   
 
​[/size]


----------



## walangalam

Nice, clean look.


----------



## V-DiV

Quote: 





walangalam said:


> Nice, clean look.


 

 Thanks.  Your recent Bijou build is really professional looking, modern compared to my creation that looks like something out of the 1950s.
   
  It's been quiet around here in Bijou land.  I guess the crowds have moved on to EHHA land.


----------



## yiancar

Guys , where can i find resistors for regels mod but with 1% tolerance ?


----------



## funch

These http://www.partsconnexion.com/resistors_prp_one_watt.html are what I used.


----------



## holland

Quote: 





yiancar said:


> Guys , where can i find resistors for regels mod but with 1% tolerance ?


 


  Digikey as well.


----------



## WyldRage

Quote: 





v-div said:


> It's been quiet around here in Bijou land.  I guess the crowds have moved on to EHHA land.


 

  
  Well, that "Super Bijou" being teased on the Cavalli website might have ade a few potential builders wait. That, and the Bottlehead Crack stealing all the OTL thunder.
   
  I just built an eXStatA Revision A for my orthos, and I have a CTH in construction for travels, but the Bijou might be my next project (that or a phono stage).


----------



## Coupe

I'm here.  I need mounting screws for the mosfets.  I am also at a holding point because of the case.  I'm not sure i'd have time to build it.  I wonder if someone would be willing to build a case for me.  I'd be willing to pay, obviously.


----------



## balderon

Quote: 





v-div said:


> My Bijou is all cleaned up now.  Here are some pictures.
> 
> - Regal's and Amphead's Mods
> - Sonicaps at C2 & C6
> ...


 

 Nice build V-DiV. The sound will only get better as the components settle in during the breakin period.


----------



## V-DiV

Thanks Balderon.  The sound is noticeably improving.  I'm very happy listening to my HD800s through my Bijou.  How does your Bijou compare to your WA6.  I've always been intrigued by the Woo amps and wonder how the transformer coupled amps sound compared to the Bijou with its output caps.


----------



## holland

nice build m46c149 and V-DiV.  V-DiV, where did you get the case, or did you make the case yourself?  It reminds me of the Decware Zen amps.  I could have sworn I posted this before, but I guess not since I can't find this, lol.


----------



## V-DiV

Quote: 





holland said:


> nice build m46c149 and V-DiV.  V-DiV, where did you get the case, or did you make the case yourself?  It reminds me of the Decware Zen amps.  I could have sworn I posted this before, but I guess not since I can't find this, lol.


 

 Thanks Holland.  The case is completely hand-made by me.  I cut and drilled the top and bottom aluminum plates from a sheet I got from an online supplier.  The grid in the top plate is aluminum sheeting for radiator (heater) covers from the local home/building supply center (Home Depot).  The front and back steel plates are also cut from a larger sheet I bought from Home Depot.  The wood sides are pre-finished maple baseboard that I had left over from some work I did in my kitchen.


----------



## pabbi1

Quote: 





coupe said:


> I'm here.  I need mounting screws for the mosfets.  I am also at a holding point because of the case.  I'm not sure i'd have time to build it.  I wonder if someone would be willing to build a case for me.  I'd be willing to pay, obviously.


 


 What type case do you want, and what size?


----------



## balderon

Quote: 





v-div said:


> Thanks Balderon.  The sound is noticeably improving.  I'm very happy listening to my HD800s through my Bijou.  How does your Bijou compare to your WA6.  I've always been intrigued by the Woo amps and wonder how the transformer coupled amps sound compared to the Bijou with its output caps.


 
   
  The WA6 has greater detail, deeper bass, and wider sound stage. I am not saying by any means the Bijou is a slouch! Much of the differences can be attributed to the expensive glass (EML 274b rectifier and TungSol 6SN7GT Round Plate driver tubes) I have in the WA6. Many agree, as I do, this combination is superb. I built my Bijou using the huge 330uF output film caps. Using these film caps has improved the sound but due to the smaller capacitance the bass is slightly rolled off as compared to the WA6. I often listen to the Bijou with my Denon D7000's or LCD-1's. Both are a great pairings. As expected the HD-800's sound wonderful on either the Bijou or WA6. Of course this is my opinion and results may vary.


----------



## V-DiV

Quote: 





balderon said:


> The WA6 has greater detail, deeper bass, and wider sound stage. I am not saying by any means the Bijou is a slouch! Much of the differences can be attributed to the expensive glass (EML 274b rectifier and TungSol 6SN7GT Round Plate driver tubes) I have in the WA6. Many agree, as I do, this combination is superb. I built my Bijou using the huge 330uF output film caps. Using these film caps has improved the sound but due to the smaller capacitance the bass is slightly rolled off as compared to the WA6. I often listen to the Bijou with my Denon D7000's or LCD-1's. Both are a great pairings. As expected the HD-800's sound wonderful on either the Bijou or WA6. Of course this is my opinion and results may vary.


 

 Thanks for the comments on the WA6.  Now I want a Woo even more.  I could see that the Bijou bass would roll off with the low impedance Denon and Audeze.  But it shouldn't with the HD800.  I have some 100uF motor run oil caps coming that I want to try with my HD800.  I want to install with a switch or binding post so I can swap the 410uF Rubicons or the motor run caps in and out depending on whether I want to listen with low or high impedance headphones.


----------



## Coupe

Quote: 





pabbi1 said:


> What type case do you want, and what size?


 

 Hey pabbi!  Great to talk to you again.  Sorry for the delay.  I will have time this weekend and I hope to take your suggestions!  I have been thinking about building a case ready to fit the balanced Bijou!  Your build in this thread has had much influence.


----------



## yiancar

finally, the amp is done 
  sorry for the fuzzy pics, ill upload some better ones when the psu is also done


----------



## nikongod

You should untwist the wires going to the tube sockets. It may look untidy but with the wires twisted together like they are you are coupling any noise on the heater wires with the signal and all the other junk and increasing parasitic capacitances.


----------



## yiancar

i thought of that but i was not actually sure. just untwisting the wires would do the trick ?


----------



## MrClean

Hi
  Just finished my Bijou, love the sound. Been reading this thread for over a month, got the kit from Glass about 3 weeks ago. Thank you for a great design and all the info.  I'm new to the world of headphones so I'm using ATH-M50  32ohm. The amp is mostly stock (for now). I would love to hear it on some different - better phones but one thing at a time.


----------



## particleman14

I see extra tubes in there...what are they for?


----------



## PoulE

Hi
  Will someone plz tell me a good place/shop to order a case for this Bijou amp ,
  I live in Denmark, so will be good a place in EU,
  and maybe also an pic/number oa
   
  Thanx
  ( one day my is ready too


----------



## SBoy

Hello,
  To all that had modified or maxxed out this lovely amp. i was wondering if you can give me some advice on maxing out my bijou as well.
  I built this amp 2 years back (stock) and am loving it with DT990/600 and i want to max it out.
  I've been reading this form occasionally and had came across some of the options like changing the coupling cap, tubes, amphead's mod.

 I don't mind spending some cash on the upgrades cause this amp is a keeper. what i have in mind is:
  changing tubes to amperex bugle boy 6DJ8
  and some bad ass caps. 
   
  Also, will these upgrades justify the sound improvement?
   
  I need some guidance here. Thanks alot.


----------



## yiancar

some good bypass caps (C6) is the best change ivemade , replaced the wima with some silver in oil Mcaps


----------



## vlb

Hi fellow bijouers!
   
   
  This is my Mods so far, Im happy to tell more about them if anyones interested. But this is my first serious build so my knowledge is limited.
   
  One Ps per chanel
  Replaced c1 with 40uf film
  Replaced c5 with 120uf film
  One 20uf film paralell with incomming 250V
  Regals mod
   
  All of theese mods have improved the sound 
   
  Ive just installed negative feedback and its a big improvement, without feedback the soundstage was a litle messy. With feedback applied the sound is much more relaxed and the freq response seems more linear.
  How do I calculate how many dbs of feedback Im applying?
   
  Is it possible to replace R3 and R7 with a constant current source ( Im not sure of the english name).
  This would give me lover distortion and the possibility to apply more bias current without changing b+, am I right?
   
  Does the choke med affect the sound or will it "only" give me more available power? If so, how much more?
   
  Thanks!


----------



## Coupe

Hello all,

 I have the board mostly populated. I was wondering if anyone would be willing to build and cut a case for me. I would obviously be willing to pay. Thank you for reading.

-Steve


----------



## particleman14

You should try what most people here do.. buy a case (par-metal, hifi2000 etc.) and then use http://www.frontpanelexpress.com/ for all your milling needs...


----------



## pabbi1

If you want to go cheap and quick, NABU is the answer. Then, take your time figuring out a permanent solution. It is almost perfect for adding a wood front panel,


----------



## S3TUP

Hi, tomorrow is the day.
  I have already powered it up, but it smoked a bit, so i'm asking for your advice:
  Should i let him smoke for a hour?
  By "smoke" i mean the scent of something getting hot. Burning oil on the tube's surface, paint on power supply resistors e.t.c?
  Probably i should clean the tubes prior to letting it run...
   
  Case from WonderCo: http://stores.ebay.com/wonderco-buy79/Metal-/_i.html?_fsub=2037457011
  Trafo from Antek.
   
  That wasn't an easy task to
   - Put everything inside such small enclosure
   - Do "symmetrical" look with asymmetrical boards 
   
  Have anyone tried Nichicon KX caps in the C5?
   
  Anyway, see the pics:


----------



## balderon

Quote: 





s3tup said:


> Hi, tomorrow is the day.
> I have already powered it up, *but it smoked a bit,* so i'm asking for your advice:
> Should i let him smoke for a hour?


 

 You have a nice, clean, and compact build S3TUP! I think it unlikely anything good would become of keeping it powered on for any duration. Something is probably wrong. Did you power up the PS by itself (with the 100k resistor across the B+ terminals) and measure/adjust the voltage? Were you able to easily set the voltage at 250v? Did you smell or see anything at that time?


----------



## walangalam

Nice build.  But smoke is not good. You should power off and check.
   
  I hope you got the orientation of your mosfets right, because you mounted them at the bottom, then you should have mounted them facing the other way.


----------



## S3TUP

The mosfets are right, caps too...
   
   
  Cleaned-up the tubes, removed thermal insulation tubes off PS CRCRC resistors - the amp quit smoking 
	

	
	
		
		

		
			




   
  Hm...
  The behavior of +250v of mine:
  Slowly rises during startup (10-15 sec), up to 252v. (it stays at zero for 5-7sec , then rapidly rises, reaches maximum and stays there for 3-5sec, and then start to drift down)
  Then slowly decreases (30-60 sec) to 248v.
   
  I'm unable to "easily" change the +B voltage, as i don't have isolated screwdriver 
  Otherwise, it has tendency to change when i turn the trimmer between startups/shutdowns.
   
  Everything is with all the tubes in place, no 100k load resistor.
   
  Tubes:
  EZ81
  6n6pi
  6n1p
   
  The transformer outputs 510v unloaded, before rectifier. could this be an issue?
  I'm running it off 220v mains.
   
   
   
  I feel myself really silly with this amp 
  When i first powered the PS section, i haven't seen any glow nor the voltage won't rise - i turned it down and rechecked everything.
  Then again and again i did this procedure, swapping EZ81, cleaning contacts etc. In the end i have figured, that it won't start up in the moment you push the power button - it needs time to heat-up, and then you'll get everything working (or smoking).


----------



## S3TUP

Ok, it seems i'vefigured out what's the problem.
  The transformer seems to be weak.
   
  The trimpot regulates well the 240-246v, but it won't let me rise the voltage up to 250v - nothing happens when i turn it futher.
   
  I've got pretty high load with these russian tubes, so maybe CRCRC resistors drop too much voltage with such current demand - i'll have to investigate it futher right now.
   
  Are there any other solutions? I don't really want to recalculate the resistors in the amplifier for 220v B+ neither want the power dissipation of 25v difference between 246 and 220v... Maybe someone already did it for 240v B+ operation?
   
  C6 300v
  C5 277v
  C4 255v
  C1 247v
   
   
  UPD:
  I've found in this thread that there is no much difference between 240v and 250v operation, as long as i have enough voltage on regulator's input. So i'll stick with 243v setting, having marginable control (up to 246v) and not much power wasted on regs.
  Now it's time for the listening session 
   
  I've got some caps to roll:
  Jamicon LP 470u 400v
  Mundorf M-Lytic 560u 400v
  Nippon Chemicon KMH 330u 200v
  Phillips 159 43221 220u 250v
  ROE EYF 470u 200v


----------



## vlb

Yes, I used those both in PS and as C5 in the amp. I later changed c5  to 120uf film wich was much better. Using hd-650.
  
  Quote: 





s3tup said:


> Have anyone tried Nichicon KX caps in the C5?


----------



## balderon

Quote: 





s3tup said:


> Ok, it seems i'vefigured out what's the problem.
> The transformer seems to be weak.
> 
> The trimpot regulates well the 240-246v, but it won't let me rise the voltage up to 250v - nothing happens when i turn it futher.
> ...


 
  Glad you discovered the source of the smoke! The low B+ is not uncommon especially with the Regal mod and russian tubes. I recall a post from Alex Cavalli stating B+ at 240v or greater should be ok.


----------



## S3TUP

Yay, it's working  On my ol' 565 sens - just for testing.
  Weirdly enough, it doesn't produce any hum although the power transformer is so close to the circuit.
	

	
	
		
		

		
		
	


	



  Probably star grounding and shielding signal wires helped a bit...
   
  The thing which worries me - are the clicking/popping noises when you take out/plug in the headphones.
  They sound unhealthy for my hd650s...


----------



## zzffnn

Can a Bijou builder kindly tell me the minimum part cost for a balanced bijou? I am selling mine and want to provide my buyer some accurate info. Thanks so much.


----------



## pabbi1

This one was about $600, with all the tubes, IIRC.


----------



## zzffnn

pabbi1 said:


> This one was about $600, with all the tubes, IIRC.




Thanks pabbi1. So indeed I am selling this amp at way below part cost.


----------



## S3TUP

What are limitations of B+ supply? I think of rolling-up the currents...
  My trafo is rated for 200ma, and i use just ~66ma.
   
  The issue i try to deal with:
  There is some threshold in the amplifier. It sounds like "noise gate" - i hear the large-signal music and it's low-signal counterparts (echoes e.t.c.). But when i try on a record which have some silence, with music rolling off the silence (volume growing) i hear some "step":
  Instead of smooth ____.......---------'''''''''''' i get __________----------''''''''''''. where "_____" is silence.
   
  I have tried the same records on other amp (chip based) and haven't heard this issue.
  By the way, it seems my Bijou lack some details against my other amp...
   
  Maybe that's what 6N1P tubes do  (i have 6N23P ordered).
  Should i address the issue to output capacitors first?
   
   
*UPD:*
  Seems i can get 100ma from the PS. The heatsink, as said, has 10C/W rating. With minimum input/output voltage difference of 10v on the regulator FET i get 1w power lost - 10c degrees temperature rise is on the heatsink.
  My 250v windings are a bit lower than on recommended 370/270 transformers, therefore i should use lower (240v) B+ voltage.
  Ok, regal mods to follow 
	

	
	
		
		

		
			





 after i fix the heatsink cooling (large hole in the case underneath the PS).
   
   
*UPD2:*
  Ok, regal mod is up and running, B+ at 238v, C4 at 249v. 73ma current draw.
  Now it's time to upgrade the convection.


----------



## vlb

I found a bouch of theese filters:
  http://img25.imageshack.us/f/20110418188.jpg/
   
  They have been used för 5-10 years, would they do any good in my bijou?


----------



## yiancar

If u plan to add both ur psu and ur amp in the same case, by adding one of those filters before the transformer, it would remove all emf caused buy the power grid  So simply yes it would help


----------



## IloveHP

Hi!
   
     I have some questions on the Bijou Amp. I have read thru the thread but my technical knowledge is very limited.
   
  A. I am very happy with the bijou amp. I have all the 0.1uf and 1uf cap replaced with Mundorf Silver Gold. This is by far the best amp I have listened too. I wonder if it is possible to increase its performance further like, replacing the huge electrolytic cap with a cap similar to the Mundorf???
   
  B. The transformer runs especially hot (370DAZ, input 230V), Should I be running a seperate filament transformer?? I have JJ EZ81, JJ ECC99 Gold Pin and Siemens E88CCA installed.
   
  C. Will building it as a monoblock include the performance of the amp?
   
     Thank in advance!


----------



## vlb

A Yes, replaceing electrolytics in the signal path with film improves SQ. If you have senns you can get away with roughly 120uf cap for output coupling.
   
  B Those hammonds get pretty hot, even within specs. Your setup skouldn´t be a problem.
   
  C Ivé built mine as dual mono. It improved SQ for me, since I couldn´t do regals mod with one PS other than that I dont know. The extra power is hans when rolling tubes too.
   
  I recomend you to try this too:
  Regals mod
  Remove cathode bypas caps
   
  I dont think Ivé heard anyone who dont like regals mod, the bypass cap is moore a matter of taste. In theory its better without it.


----------



## SBoy

Quote: 





vlb said:


> A Yes, replaceing electrolytics in the signal path with film improves SQ. If you have senns you can get away with roughly 120uf cap for output coupling.
> 
> B Those hammonds get pretty hot, even within specs. Your setup skouldn´t be a problem.
> 
> ...


 

 How do you know what amount of uf to put in the output? i pair bijou with a DT990/600 ohm and was planning to upgrade the output caps. Everything in my bijou is stock


----------



## yiancar

i guess experimenting but am not sure, if u replace the huge electrolytic with a plastic one u'll no need a bypass cap then so just remove it 
  Also i havent done regals mod as i am obsessed with resistor accuracy and cnt find that high W with 1% offset, if anyone can show me a shop it i would appreciate


----------



## vlb

SBoy:
  I only know the calculation the other way around, how to calc -3db freq with a given resistance and capacitance.
  fc  = 1 / (2*pi*R*C)
  Just remeber to enter the capacitance in F and not uF.
   
  If you have a texas ti 82 or similar you can enter this to get a graph on the cutoff.
  319/sqr(319^2+(1/2pi*X*120e-6))^2  319 is the headphones impedance and 120 is the capacitor size in uf.
   
  I tried some values, signal level @ 20hz into 600ohm
  60uf - 97,6%
  40uf - 94,9%
  30uf - 91,5%
  20uf - 83,3%
   
  yiancar:
  Regals mod will improve sq much more than perfectly matched resistors.You can buy a couple extra resistors and measure them yourself. If your really picky you can heat them in the oven first so the resistance settles.
   
  I have a question too:
  Will the choke mod improve the sound of the amp?


----------



## SBoy

Quote: 





vlb said:


> SBoy:
> I only know the calculation the other way around, how to calc -3db freq with a given resistance and capacitance.
> fc  = 1 / 2*pi*R*C
> Just remeber to enter the capacitance in F and not uF.
> ...


 

 well, i do know how to calculate the value of the cap from the given db freq, but how much is of a drop is sufficient? is it totally up to our preference and we just play around with the value? 
   
  Heat them up in the oven? wow, i didn't know that! lol. let us know how it goes yiancar.


----------



## pabbi1

WRT 6n1p, I found that they take 50-100 hours to get rid of the static.


----------



## vlb

Quote: 





sboy said:


> well, i do know how to calculate the value of the cap from the given db freq, but how much is of a drop is sufficient? is it totally up to our preference and we just play around with the value?
> 
> Heat them up in the oven? wow, i didn't know that! lol. let us know how it goes yiancar.


 
   
  I want the amp to be "totaly" linear 20hz-20khz so I use a 120uf cap with 330ohm senns. It gives me -3db @ 4hz and 97.9% at 20hz. But of course its a matter of taste. I recommend a little NFB if you go big with this cap, the lowest bass feels slow and slobby without it, at least in my setup..
  
   
   
  Edit:
  Found this page: http://my.hrw.com/math06_07/nsmedia/tools/Graph_Calculator/graphCalc.html
  Just enter 319/√(319^2+(1/(2π*x*0.000120))^2)
  Replace 319 with you phones impedance at both positions, and replace 120 with you capacitor size in uf. This gives you a graph on the lower limit of the bandwidht.


----------



## SBoy

Quote: 





vlb said:


> I want the amp to be "totaly" linear 20hz-20khz so I use a 120uf cap with 330ohm senns. It gives me -3db @ 4hz and 97.9% at 20hz. But of course its a matter of taste. I recommend a little NFB if you go big with this cap, the lowest bass feels slow and slobby without it, at least in my setup..
> 
> 
> 
> ...


 


  Thanks vlb, i will still have my NFB as im driving a wide range of headphones.


----------



## vlb

Quote: 





yiancar said:


> If u plan to add both ur psu and ur amp in the same case, by adding one of those filters before the transformer, it would remove all emf caused buy the power grid  So simply yes it would help


 


  So it won´t do any good as long as the ps is in a separate box?


----------



## funch

Has anyone here ever found what the actual output in watts is, with ECC99's?


----------



## wdahm519

Just finished my Bijou!
   
  I would say the output wattage is about 1/2W.  
   
  I didn't measure the wattage though.


----------



## nikongod

Quote: 





funch said:


> Has anyone here ever found what the actual output in watts is, with ECC99's?


 
   
  Do watts equal sound quality? the proliferation of truly horrid sounding 500-1KW speaker amps and the small but obvious army of amps that actually sound quite nice putting out only 10-75W brings the value of the watt into question. Its almost worth looking for LESS power considering the trends. Perhaps exactly as much as you need? like for example if you only need 1W to drive your speakers you give yourself a healthy 20db of headroom and buy a 10W amp. Or if you only need 10mW to drive your headphones you build a 100mW amp (1/10<1/8)
   
  On that note you will be lucky to get 1/8W out of the bijou (are you lucky to subject yourself to SPL in the 110db+ range? I guess its a matter of perspective). This is conditional on the amount of feedback used, and the load impedance and will usually be LESS! heh. Its a good thing that for conventional dynamic headphones not even 1/8W will get your headphones singing loud enough for all but the most hardcore.


----------



## funch

Thanks for all the info.
   
  I ask because I'm thinking real hard of getting a pair of LCD 2's, and they seem to need a few watts to properly power them.
  At the AZ meet last weekend, we had a member bring his Leben 600, which has just under a watt output at the headphone
  jack. The LCD's sounded OK out of it, but much better when he hooked them up directly to his speaker outputs.
   
  I tried his LCD's on my Bijou, and it seemed to drive them fine, but after hearing the differences on the Leben, I'm wondering
  if my Bijou really has enough to drive them with authority.


----------



## wdahm519

How does the power consumption compare with the LCD 2's versus HD800's and T1's?


----------



## nikongod

Im 50/50 on the whole driving orthos thing. 
   
  I generally take a very minimalist/low power approach to headphones, and IME it sort of works with orthos although I do generally prefer orthos when driven from an amp that can put several watts or more into 8ohms.
   
  I should also note that I prefer my HD800 from an OTL amp to orthos from pretty much anything. I prefer the soundstage-width on the HD800, and Frequency response between them is close enough to EQ.


----------



## yiancar

Quote: 





vlb said:


> So it won´t do any good as long as the ps is in a separate box?


 


  Theoretically if the ps is in a separate box, the emf caused by it would will not affect the amp box(and therefor its components) so no. But if u have some lying around just use them, remove as much variables from the equation as u can


----------



## milosz

I have a Bijou and LCD 2's.  It does not drive them to my full satisfaction.  It's close but not quite a cigar.  See http://abtests.org/ns/hpamps/8.html
   
  My Bijou
   

   
   
   
  Here's how I fit it in that small case


----------



## vlb

Im finaly doing the last work on the case, but I want to be done with all mods (for now) before I close the lid.
  Im going to try 6n30p and 6n6p.
  Ive got some spare power since Im using 2 hammond 370daz.
   
  Would the 6n30ps benefit from higher bias than regals mod?
  If so, can you recomend resistor values?
   
  Edit:
  Would it be possible use 6n6p as input tubes?


----------



## vlb

Does anyone know how much current the ecc99 and 6n6p output draws?
  How much current does the power supply with ez81 offer?


----------



## yiancar

u mean heater current? if yes both need 800mA
  Y is it important how much the psu will offer?
   
  PS u cannot use 6n6p as input tube


----------



## vlb

No I mean HT current. I built my bijou as dual mono with one 370daz per channel so Ive got some spare power.
  Im reading "valve amplifiers" by M.Jones and I think Ive "mastered" the calculations to bias the input tubes, so I want to know how much current B+ will deliver.
  But I gues Im being lazy, some power resistors a osciloscope and some spare time will give me the answear.


----------



## yiancar

Oh i see  would love to make some measurements for u but currently i dnt own an oscilloscope


----------



## funch

My Bijou has a new face.
   

   
  I also added a three-way power switch with front panel acces. The old, blue faceplate is still there, with the controls
  still mounted to it. The new one mounts over the old one.


----------



## jdkJake

Sweet!
   
  Did you farm that out or did you do that yourself?
   
  Lot's of personality!


----------



## funch

Thanks. It's from FPE.


----------



## Coupe

Pabbi's amp has a new home!


----------



## yiancar

Sweet post some pics


----------



## pabbi1

It needs to be recased... seriously... but, how does it sound? I haven't heard it for about 2.5 years. I would love for someone to step it up from 6n1p/6n6p, to at least some 6n23 or 6h30. She is a beautiful thing with Senn or LCD-2.


----------



## funch

So your Bijou worked well with the LCD's? I tried a pair with mine at our AZ meet recently, but it seems that they really work better with a couple of watts.


----------



## pabbi1

Ah, the one I built was balanced, with a wee bit of extra gain... it would even drive k1k pretty well.


----------



## Coupe

I decided to bring it down. I noticed one of the caps on the output has a hump on top. I remember reading that there is a chance of a slimer  

I checked voltages at the output of the PS and there is 250 VDC and it adjusts fine.
The other PS is 260 VDC and won't adjust.

O well I guess its time to re-read the thread again and try to find solutions.
Knew I should of taken notes :mad:


----------



## Coupe

Durr maybe I should just ask you guys!
   
  What are voltages I should check? What should the values be?  All the tubes light.  I have a fluke multi.
   
   6.3v AC at the heaters I use both leads on both wire inputs
  290v AC at the PSU inputs at each of the 4 260V AC inputs using star as ground
   
  250v DC output on 1 PSU
  265v DC output on the other PSU.
   
  Should I measure something else?


----------



## jdkJake

I would start here as all of the expected voltages are nicely documented:
   
  http://www.cavalliaudio.com/diy/bijou/main.php?page=troubleshooting


----------



## Coupe

Quote: 





jdkjake said:


> I would start here as all of the expected voltages are nicely documented:
> 
> http://www.cavalliaudio.com/diy/bijou/main.php?page=troubleshooting


 


  Ahh nice TY I forgot about that


----------



## Coupe

Sorry for the post spam.
   
  I wasn't sure what side of the resistor to measure.  Does voltage increase after going through the resistor?  Is that a constant?
   
  PSU #1
   
  Input #1 : 290 V AC 
  Input #2 : 290 V AC
  Output  :  248 V DC
  R7        : 288 V DC and 252 V DC out
  R8        : 324 V DC and  288 V DC out
   
   
   
   
  PSU #2
  Input #1 : 290 V AC
  Input #2 : 290 V AC
  Output  : 265 V DC
  R7        : 300 V DC and 270 V DC
  R8        : 332 V DC  and 300 V DC


----------



## jdkJake

Voltage does not increase going through a resistor. In fact, just the opposite is true.

In order to determine which side to measure, you need to follow the schematic and actual board layout and see the next part in the sequence. That will indicate the proper side to make the measurement.


----------



## yiancar

Just guessing but check that the Z1 diode is correctly oriented ( i did put it the wrong way the i was stuck at about 260V)


----------



## Coupe

Quote: 





yiancar said:


> Just guessing but check that the Z1 diode is correctly oriented ( i did put it the wrong way the i was stuck at about 260V)


 


  Thank you for the suggestion.  However, this amp was pabbi's and although it has gone through a few owners; I doubt anyone would change the diode from a working amp.


----------



## zibra

hello
  can you confirm that bijou kit could be an upgrade from ss matrix m stage? that budget ss got great opinions but I think theres some lack of power and general I feel that cans have even more potential to discover. I use vintage beyerdynamic dt880S/600ohm. anyone went such path from great budget ss to bijou?


----------



## Coupe

So been reading the thread and judging from the symptoms of the non adjustable voltage I should change the mosfets.
  Does that seem right?
   
  Checked the BOM on Runeight's site and the mosfets are not available on mouser.  Can anyone recommend mosfets to buy?  What are the important specs for future reference?
   
  Thank you much!


----------



## krtzer

I've been thinking about building this amp for a while, and was wondering how would it pair with the HD600s? I haven't found too many people who talk about how they compare. To be fair, I didn't go through all the pages of this thread, but I did use the search function with minimal results.


----------



## yiancar

this
http://uk.mouser.com/ProductDetail/Vishay-Siliconix/IRF820APBF/?qs=sGAEpiMZZMutXGli8Ay4kCPNvF3z2Oenq%252bUEjnm6bBk%3d
or this 
http://uk.mouser.com/ProductDetail/Vishay-Siliconix/IRF820PBF/?qs=sGAEpiMZZMutXGli8Ay4kCPNvF3z2OenC%252bhoAYP2w2M%3d

can also be used


----------



## vlb

Im about to order parts from mouser to upgrade my bijou but Im having trouble finding a good 250k 2 channel pot for NFB, any suggestions?
   
  Im Also looking for a soloution to remote control the volume, but I have very limited space inside the casing.
   
  Krtzer, Bijou is great with my hd650 and they arent so different from hd600.


----------



## funch

Balderon used this one: http://cgi.ebay.com/ALPS-250K-DUAL-LINEAR-CONTROL-POT-/150510750996?pt=LH_DefaultDomain_0&hash=item230b23cd14 
   
  Make sure that whichever one you choose is linear, not logarithmic.


----------



## vlb

Thanks
   
  Ive been thinking about ebay, but how do I tell a real alps from a copy?


----------



## jdkJake

Always a legitimate concern with eBay. Pay close attention to the feedback.

Mouser has them, but, with a 14 week lead time and minimum 100 quantity order, that is somewhat impractical.

Seller familygate has them as well. They are recommended by a few folks around here:

 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=260778161321


----------



## vlb

Ill think I have to take a shot at the first one, familygate only  have 250k log. The 250 lin seems to be rare.
   
  Can you recommend a good source for nobs? I think I want big metal nobs.


----------



## funch

These are nice:http://cgi.ebay.com/GOLDPOINT-1-4-ALUMINUM-KNOB-/150511351780?pt=LH_DefaultDomain_0&hash=item230b2cf7e4 .


----------



## Coupe

Thank you so much for the MOSFET parts!  Both PSUs are alive @250Vs and the amp lives!  Thank god for that Hakko Desoldering gun!  Incredible investment.  
	

	
	
		
		

		
			





  Friday night...
   




   
   
  Saturday 
   
   
    There is a ticking sound with a computer source plugged in. Also there is a buzz that changes with volume, not as noticeable.  Let's tackle the tick first.  The tick disappears when the input is unplugged. The tick increases with the Bijou volume, but does not change with the source/computer volume.  The noise was interfering with listening enjoyment, so I switched back to the FiiO E9.  *Interestingly enough, I heard it on the E9 for the first time.* 
	

	
	
		
		

		
		
	


	




    What could this be?  I noticed one of the input shield grounds was broken and fixed that.  So, After re-soldering all the input shield grounds and trying again on the Bijou, the tick was still there.  It didn't change with volume... ARGH!  Well after many trips to the 10k resistor I decided to put this down and sleep on it.  Wake up refreshed and continue today.
   
    Went to bed, 5 AM.
   
    Woke up 10 AM to... Why wasn't this here before, when the amp was received and had bad MOSFETs?  More importantly why was there a tick on the E9?
   
    I asked myself, what changed?  Why didn't I notice this with the E9 before?  It was VERY noticeable.  The first guess was my motherboard.  The motherboard southbridge fried (meh on that one) after the Bijou was taken offline because of the bad MOSFETs. Changed from a 5850 to a 6950 and then CF the 6950s  However, I have been using the E9 every day since then.
   
  The source...?  So I started unplugging all peripherals.  Video, mouse, keyboard, other USB pl.... wait.  It's gone on the E9.  Where did this USB go to.....?   Ahh it's the DAC connect for when the E7 is plugged in.  I plugged it in to make using the E7 easier (so much for streamlining)!  Plugged in some low resistance D2000s and tested with Line in.  Turned the volume way up and there is static and the tick at max volume, with gain on, nothing noticeable at all, given that I would never put the E9 with that volume.
   
    So I decided to plug in the E7 to test a digital signal for interference.  I put it in and it didn't mount.  
	

	
	
		
		

		
		
	


	




  Jeez what could it be now.  Took the E7 out and I noticed the dock connector on the E7 is now broken.....  Now poor Micca is involved in this saga.
   
    So the movie continues.  It's funny because I always try and be careful with devices that could be fragile.  The E7 dock connector is not the highest quality.  This isn't a knock on FiiO.  Either you can't think of everything, or there is only so much awesomeness you can squeeze out of a sub $100 portable DAC/AMP.  As you can see, from the video I treat my audio components well.....  What can I say I like resting with solder beads and wire wrappings. 
	

	
	
		
		

		
		
	


	



   
  So, I then plugged in the USB connector on the E7 and 1/8th it to the E9.  No tick just normal hiss at ultra high volumes.  This must be an issue with the common factor of two plugs!  The PCI-e bridge is common to the USB and the sound card.  How to test?  Hmm.  Let's try USB E7 -> 1/8th E9 and leave the USB connector in the E9.   The hiss is increased, but no tick.  The USB for the E7 is a top connection.  Let's move the E9 USB to the top connection with it.  Hiss the same.  OK, So the tick isn't passing through the PCI-e bridge.   Now let's plug the 1/8th from the soundcard into the E9.  We will leave the USB connector to the E9 @  the top connector of the PC Case.  The tick is back!
   
    So this isn't a PCI-e interference.  Don't think its location issue (USB wise). The USB  front panel connector is on the bottom; however, it's shielded and runs through the back of the case.  The case is aluminum.
   
   It wasn't present on the old MB with the Auzentech/Bijou before it was taken down.  However, I don't remember if I added the second 6950 after the Bijou was taken down.
   
  Recap:
   
  Auzentech 1/8th (amp out or front out makes no different) -> Bijou - tick increases with amp volume / no change with source volume. **note* Computer activity also provides interference.*
  Auzentech 1/8th -> E9 - unnoticeable tick
  Auzentech 1/8th -> E9 w/ USB plugged in any location - tick
  Docked E7 -> E9 w/ USB Plugged in -> 
	

	
	
		
		

		
		
	


	



  USB any location E7 1/8th -> E9 - 
	

	
	
		
		

		
		
	


	



  USB any location E7 1/8th -> E9 w/ USB plugged in any location -> Amplifies hiss
  USB any location E7 1/8th -> Bijou - Hiss, no tick **note* Computer activity also provides interference.  Even w/ E7 turned off, but USB plugged in/charging.*
   
  What would you guys suggest as the next steps, for either the tick or the buzz?


----------



## yiancar

After a long time i completed my first tests,
   
  One of the caps was smoking like the case in the previous 3 pages and also i got a rather high heaters v, ~7 to be exact, any way to lower it? shall i add a resistor?


----------



## MrClean

Quote: 





yiancar said:


> After a long time i completed my first tests,
> 
> One of the caps was smoking like the case in the previous 3 pages and also i got a rather high heaters v, ~7 to be exact, any way to lower it? shall i add a resistor?


 
   
  I been running my amp with 7.4vac heaters for 2 months, tubes are ok but decided to lower it to safe level. here is advice I followed :
   
  http://www.head-fi.org/forum/thread/560333/please-help-to-lower-ac-heather-voltage
   
   
  my latest upgrade was to add 250v switch, choke, change power supply to film caps and add 2 transformers for l and r channel heathers so I decided to build transformer box that doubles as rolling tube holder
	

	
	
		
		

		
		
	


	



  after removing feedback pot I decided to get switch for cathode resistors. now tube rolling takes 2 minutes at the most.


----------



## yiancar

nice casing , also tnx for the link ill do some current measurements 

 Btw if i measure correctly , i see 7 tubes on ur amp , what are those extra 2 used for?


----------



## yiancar

Here are some pics 
  Its a balanced setup , with a separate housing for the psu.

   
  A closer shot

   
  Closeup of the tubes

   
  The back

   
  And the inside of the psu

   
  Its rather difficult for me to open the amp case now but i think I've posted some pics in earlier posts 
   
  Comments are welcome


----------



## jdkJake

Nice build!

Are you running with or without the negative feedback?


----------



## Jrossel

Has anyone driven low impedance cans with their Bijou? 
  I would like to know if the amp can drive  24 Ohm  headphones?
   
  Thanks for your help.
   
  Jeff


----------



## yiancar

without, less interference and less things to cross out when things dont sound correct  however i need to mention that i use HD650 so my phones have rather high independence


----------



## yiancar

Quote: 





jrossel said:


> Has anyone driven low impedance cans with their Bijou?
> I would like to know if the amp can drive  24 Ohm  headphones?
> 
> Thanks for your help.
> ...


 

 There are some good opinions in very early posts, try searching the thread a bit . Overall though most people use high impedance phones with the amp


----------



## Coupe

Amazingly beautiful and humbling builds!  You guys are incredible!


----------



## balderon

Quote: 





jrossel said:


> Has anyone driven low impedance cans with their Bijou?
> I would like to know if the amp can drive  24 Ohm  headphones?
> 
> Thanks for your help.
> ...


 

 I have had no issues driving 40Ω LCD-1 or 25Ω Denons with JJ ECC99 drivers.


----------



## vlb

Wow, you guys really master the art of casing.
   
  I hate casework and since I decided to go p2p and dual mono with separate chassis power supplys I have to suffer through a lot of it. And now I have to add an extra section to the amp chassi to house film capacitors and remote controll unit...
   
  Anyway, a have o few problem and hope you can help.
   
  Is there any solvent I can use to get superglue of aluminium?
  Where do I find those "rings" you put around the tube sockets to cover the screws?


----------



## balderon

Try acetone based nail remover to dissolve the superglue.
   
  Take a look at the accessories at vt4c. http://www.vt4c.com/shop/program/main.php?group_id=2


----------



## mugdecoffee

Quote: 





jrossel said:


> Has anyone driven low impedance cans with their Bijou?
> I would like to know if the amp can drive  24 Ohm  headphones?
> 
> Thanks for your help.
> ...


 

 I tried mine with a pair of 32ohm Grados and thought it sounded pretty bad, very flat and bland sounding.  Not sure if that was a problem of impedance or just pairing.


----------



## yiancar

Quote: 





vlb said:


> Wow, you guys really master the art of casing.
> 
> I hate casework and since I decided to go p2p and dual mono with separate chassis power supplys I have to suffer through a lot of it. And now I have to add an extra section to the amp chassi to house film capacitors and remote controll unit...
> 
> ...


 


   


  Quote: 





balderon said:


> Try acetone based nail remover to dissolve the superglue.
> 
> Take a look at the accessories at vt4c. http://www.vt4c.com/shop/program/main.php?group_id=2


 

  
  As Balderon told vt4c has some amazing stuff  My rc sockets, tube sockets and transformers  are also from there. It has some awesome cases too  My casework was done by hifi2000 and some of my noobish autocad skills 
   
  Also can you guys point me to some good rotary switches? I need to make a passive xlr source selector and i dnt really see the point of using relays


----------



## jdkJake

yiancar said:


> Also can you guys point me to some good rotary switches? I need to make a passive xlr source selector and i dnt really see the point of using relays




I am fond of these:

http://www.goldpt.com/selector.html


----------



## vlb

My bijou is up and running again after a few mods. Now using 6n6p as output, I was really dissapointed as first, the sound was lifeless and sharp to the ears. After 20 hours burn its much better but still not sure if its better than ecc99. 
   
  Im going to run it without chassi for a few weeks at least to try more mods. I have to rebuild the chassi to fit my huge output caps...
  Running dual mono so Ive got some spare power right now.
   
  The next mod will be to try 6n30p as input and bias it at around 15-20 mA. Im not 100% on how to do it yet, but Im working my way through Morgan Jones books.
   
  Im thinking about the possibillity to use 6n30p as output, do you think it would be worth a shot?
   
  Il need to determine how much current I can draw from the PS to. Im thinking about monitoring B+ with a scope while applying an increasing load with resistors, would this be a good method?
   
  My half finished build, currently runnings as preamp for Magnepan 3.5s:
  http://imageshack.us/photo/my-images/88/20110712404.jpg/


----------



## yiancar

Ur psus are pretty nice  in my trial with 6n6p i didnt really like it even after some days of listening ecc99 for me, What caps are u using?
  About a dummy load you can try this http://www.youtube.com/watch?v=8xX2SVcItOA or this http://www.hlektronika.gr/forum/showthread.php?t=45738&highlight=dummy+load second link is in greek but if u use google translate ull get some nice info. both are active dummy loads therefor the max value will be mode accurate than using resistors 
   
  U may need to change the fet though to be able to survive 250v


----------



## vlb

Thanks, Im pretty sure it will look good when its all done...
   
  Im Using 120uf 900v film caps, Ive lso removed the cathode bypass caps and replaced c1 with 40uf film. Theese mods made the sound very controlled and dynamic. Next Im going to try if bigger caps at c3 and c4 will make a difference.
   
  Regals mod was a big improvement to, and in my taste NFB makes the sound smother and more detailed.
   
  Thanks for the tips on the load!
   
  Have you compared your balanced build to an unbalanced?


----------



## yiancar

As i have a balance/unbalanced switch (similar to the b22 circuit) the comparison was done (with both unbalanced and balanced sources).
  The balanced mode seems more full and dynamic than the unbalanced one. I want to describe it as powerful but without the meaning of more volume. As most balanced setup bijou is improved .
   
  In my setup i changed the coupling caps with film  and the bypass caps with mundorf silver in oil. Ur 120uf is the c5 cap? if so isnt it small in contract to the 470uf of the electrolytic that was there?


----------



## vlb

Im sorry to hear that
  Of course I want it to be even more full and dynamic. But I dont want to build all this one more time. It would be pretty riddiculess too, some kind of dual mono, dual mono and a total of 6 chassis...
   
  Yes my 120uf is in C5 position.
  Since Im using Hd650 (330ohm) 120uf gives -3db at 4hz and 98% signal level at 20hz. 470uf -3db at 1hz and 99,8% at 20hz. I dont think you can hear that difference, but you surely will hear better clarity in the sound with films.
   
   
  Post explaining how to get a graph on it. Both online and on a texas ti.
   
  http://www.head-fi.org/forum/thread/277541/bijou-all-tube-futterman-headphone-amplifier/3870#post_7431430
  http://www.head-fi.org/forum/thread/277541/bijou-all-tube-futterman-headphone-amplifier/3870#post_7433127
   
  Have you tried your bijou as a preamp?
  I think it brings a nice tube touch to the sound espially in the summer when I cant use my 250w tubeamp, I can´t stand the heat and the amp eats 16 6550s every 2000hours.


----------



## yiancar

no not really, But i figure it would be a nice preamp ivegot a grate problem though , both my psus without load they give a nice 250V output however one of them today magicly decided that when it sees load it should drop to 150v. I am so confused i tried everything with no result, any ideas?


----------



## vlb

I would suspect the fets since they seem to be most likely to fail.
   
  You can try to measure resistance at different places in the circut and compare to your working PS,  I think thats a pretty good way when you don´t know what to do.
   
  Im thinking about the possibillity to dubble up the ecc99s and use them in paralell with the original ecc99s, would it be woth a shot?
   
  http://imageshack.us/photo/my-images/546/ijoudualver2.gif/
   
  In my head this would lower the output impedance and distortion, am I right?
  Or would all benefits be lost because of the increased load on the phase splitter?
  Do I need to change R9,11 and C3,4?
   
  Edit: Im done with my listening test, 6n6p vs ecc99 and I prefer ecc99. They seem more detailed and dynamic.


----------



## yiancar

oh boy bad fets. just replaced them with some irf840 to be fair they run hotter but who cares ? they work


----------



## _Snoopy_

I recently got hold of a perfectly matched pair of 12AU7WA's. Has anybody tried these as a replacement for the ECC99 output stage tubes?
   
  Regards,
  Snoopy


----------



## funch

I don't believe they will work, as they use 12.6V heaters.


----------



## balderon

Quote: 





_snoopy_ said:


> I recently got hold of a perfectly matched pair of 12AU7WA's. Has anybody tried these as a replacement for the ECC99 output stage tubes?
> Regards,
> Snoopy


 
   
  The pinouts are the same and many of the specifications are close enough but there are some differences. The maximum cathode current of the ECC99 is 60mA verses 22mA for the 12AU7WA. Also the maximum plate dissipation for the ECC99 is 5W verses 3W for the 12AU7WA. I don't know what the Bijou is drawing and I am not 100% confident (yet!) in the proper equations to compute said values. As such, I would be hesitant to try the 12AU7WA.


----------



## Navyblue

We use 230V mains here. I wonder if it is desirable/possible to build a version of Bijou that runs without a transformer?


----------



## nikongod

The output impedance with a 12au7 will be much higher than with the ecc99. The operating points will also need to be changed to fit the tube. 
   
  I dont think that matched tubes will make a difference in a Bijou anyways, save them for somewhere where they might.
   
  Quote: 





navyblue said:


> We use 230V mains here. I wonder if it is desirable/possible to build a version of Bijou that runs without a transformer?


 

 It is possible to build all sorts of mains-coupled amps. Dont. It was common practice in older table-top radios to try to save money. They stopped production really quick when they realized how easy it was to electrocute yourself - without opening the case.


----------



## _Snoopy_

Thanks for the input, folks. So I think I'll stick to the ECC99s.


----------



## yiancar

Guys any shop which sells perfectlu matched tubes?


----------



## jdkJake

What is your definition of "perfectly matched"? With tubes, "close enough" is probably a better target. 

Lot's of places will match tubes within a few percentage points. Realize, there is no guarantee they will actually perform identically at your operating point. Matching just means they tested close at a particular test point which is generally not representative of the actual operating conditions the tube will be used at.


----------



## yiancar

so matching them myself would be the best way right? any easy way of doing it no scope or signal generator here :/


----------



## nikongod

Quote: 





yiancar said:


> so matching them myself would be the best way right?


 

 Forgetting about matched tubes would be the best way.
   
  It may sound somewhat generic at first glance, but is the quest for matched tubes on an amp that does not require them any less generic? Its really a generic quest in many amps... something people do for no reason other then that's what they generally do.


----------



## jdkJake

yiancar said:


> so matching them myself would be the best way right? any easy way of doing it no scope or signal generator here :/




So, to pull on the comments from Nikongod a bit farther, why do you believe perfectly matched tubes are important?

You could certainly test with a tube tester. You could also test them in circuit if you want to go through the effort. That would probably be more accurate. One could argue you should also modify the circuit appropriately to find the "sweet spot" for a particular tube or set of tubes rather than search for the perfect tubes for the circuit.

It really depends upon how much work you want to put towards it.


----------



## Coupe

On a balanced bijou, should the left and right channels be in phase or out of phase? What are the benefits and repercussions of each?
   
  Thank you!


----------



## nikongod

Unless you have a very good reason* to do it any other way the left and right channels should always be in phase.
   
  *There is a technique of wiring single ended amps and speakers with one channel "double out of phase" as an effort to improve the performance of the amp. The end result is that the sound is in phase, but the electronics are out of phase. Nobody does it because they can sell monoblocks for what a stereo amp costs and its tricky to explain. This technique has basically no effect on amplifiers with balanced power stages, so dont worry about the Bijou, just posting because maybe someone will use it to their advantage someday.


----------



## Coupe

Hey Ari!  how are you doing?  Is there a way with a DMM to test the phase on each amp channel so it's notw ired wrong?


----------



## nikongod

If your using the RCA inputs Im pretty sure that the 2 outputs will both be in phase on your amp. You run into trouble with balanced amps and amps with transformers: OTL's are usually pretty tame for phase. The bijou does invert phase, but since it does the same to both channels its not important. You run into real trouble when one channel is in phase, and one is out. 
   
  Since both channels are probably in phase by default when using the single ended inputs, Just check that the right XLRs are hooked up to the right boards. plug in only one XLR, if sound comes out of only one channel your good. 
   
  If you realllllly want to check it out there is a way, but its probably easier to just listen. 
   
  I would start by just tracing the signal from the jacks through the amp boards and out with the amp off, and after discharging the caps... Use a DMM set to ohms for this - nice and quick. 
   
  After that, or with an amp with transformers:
  Connect 2 100 ohm resistors together. Love the alligator jumpers. 
  Connect the ends of the resistors to the SE outputs of the amp. 
  Play a mono sine wave into the RCA jacks. Best way is to just use one output from your source and use a y-spliter to both inputs. I have 440hz saved on a CD just for this.
  Turn up the volume until you have about 0.5vac from either (both!) end of the resistors to ground. 
  Measure ac volts from the CENTER of the resistors to ground. If its about 0.5vac, your good. if its ~0vac your out of phase.


----------



## yiancar

wow nikon very clever technique 
   
  as for my tube balancing quest, it seems more "correct" for the tubes to be balanced but as u guys explained lots of trouble with minimal gain


----------



## MrClean

Hi
  I've been using my heavily modded  Bijou with LCD-2 which are  50 ohm  and love the combination, bass is superb,
  my output caps are 3 x 150uf of solen film bypass by 1uf mundorf silver oil, I've been wondering, would the amp get damaged if I connected it to
  8 ohm speakers?
  Fostex 207e driver 95db/w that I use with 2a3 set.
  Any answer other than "try it and let us know what happens" would be helpful.


----------



## ericj

So i just bought qty3 Voskhod 6n23p on ebay. 
   
  I searched the thread and saw some favorable impressions of them, but does anyone have a fully formed, over-the-novelty opinion on them? I bought the trio because i need a 6dj8 type for a completely different project (a chip amp with a tube buffer) but since I got three of 'em . . . . 
   
  I am of course currently running 6n1p-ev and 6n6p-i and find the sound signature to be warm, syrupy smooth, engaging, etc. relaxing as all getout, which is why the bijou is next to my bed. 
   
  So, anyone who listened to the 6n23p in this amp long enough to get tired of it - what do you think? 
   
  Especially interested if you have compared them to 6n1p.


----------



## ericj

Quote: 





mrclean said:


> Hi
> I've been using my heavily modded  Bijou with LCD-2 which are  50 ohm  and love the combination, bass is superb,
> my output caps are 3 x 150uf of solen film bypass by 1uf mundorf silver oil, I've been wondering, would the amp get damaged if I connected it to
> 8 ohm speakers?
> ...


 

 This amp doesn't have that kind of power. 
   
  At best there will be almost no bass. 
   
  Try the bijou as a preamp hooked up to your favorite solid state power amp instead.


----------



## pabbi1

Quote: 





ericj said:


> This amp doesn't have that kind of power.
> 
> At best there will be almost no bass.


 
   
  Balanced it does...    


 Quote:


ericj said:


> So i just bought qty3 Voskhod 6n23p on ebay.
> 
> I searched the thread and saw some favorable impressions of them, but does anyone have a fully formed, over-the-novelty opinion on them? I bought the trio because i need a 6dj8 type for a completely different project (a chip amp with a tube buffer) but since I got three of 'em . . . . I am of course currently running 6n1p-ev and 6n6p-i and find the sound signature to be warm, syrupy smooth, engaging, etc. relaxing as all getout, which is why the bijou is next to my bed.
> 
> ...


 

 I am a big fan of the 6n23p, and think they are a serious upgrade over the 6n1p, especially the -ev. I also liked them in my source far better than the stock EH 6922 (iirc), but not as well as the CCa (the eventual winner), which is teamed with some 1980 date code 6H30-DR, which might well be masking everything else. Sadly, the amp I targeted the 6n23 for (Raven) is now in other, more capable, hands. I was also wanting to hear some feedback on the 6n23 in the LF, and dedicated my remaining tubes for someone to roll these in, but haven't heard yet... but, didn't find the 6n23 until after I'd sold the Bijou.


----------



## IloveHP

How do I use it as a Preamp? Any special modification needed?


----------



## wdahm519

When I built my Bijou I added phono L/R outputs in the rear to use the Bijou as a preamp.  Basically you just wire the outputs in parallel (I think, its been a while) to the headphone output.


----------



## ericj

Quote: 





wdahm519 said:


> When I built my Bijou I added phono L/R outputs in the rear to use the Bijou as a preamp.  Basically you just wire the outputs in parallel (I think, its been a while) to the headphone output.


 


  Yes, just wire them in parallel or use a switched jack such as the neutrik jacks.


----------



## wdahm519

Quote: 





ericj said:


> Yes, just wire them in parallel or use a switched jack such as the neutrik jacks.


 


  What he said..


----------



## bhjazz

Quote: 





ericj said:


> Yes, just wire them in parallel or use a switched jack such as the neutrik jacks.


 

 Good information.  I'll do that once I get back to building this.  
  Picked up a Goldpoint 50K miniV for my Bijou build just last week.  All I really need now is a case design I can work towards, and TIME!  Geez.


----------



## glenda

If I look at the output stage we have the 6n6p biased with 3 diodes =2.3V,  am I correct the the max output of this amp is 2.3Vx2=4.6V ?


----------



## getintechtom

Hi guys,
   
  I'm purchasing a Bijou from a fellow member and would like to know what needs to be done to be able to switch from ECC99's to 12BH7 power tubes.
   
  There's more of a variety of 12BH7's (as well as other models) to go through some tube rolling. I know some rewiring needs to be done on the heater elements.
   
  Any info would be appreciated.
   
  Thanks
  Thomas


----------



## bhjazz

Quote: 





getintechtom said:


> Hi guys,
> I'm purchasing a Bijou from a fellow member and would like to know what needs to be done to be able to switch from ECC99's to 12BH7 power tubes.
> There's more of a variety of 12BH7's (as well as other models) to go through some tube rolling. I know some rewiring needs to be done on the heater elements.
> 
> ...


 

 Hey there, Thomas, 
   
  For starters, you should read up at the designer's site about the Bijou if you haven't already.  That is here.  
   
  However, regarding moving to 12XXX tubes Alex says, 
   
  "...WARNING: Do not use tubes which have a heater tap on pin 9. This includes all of the popular 12XXX series tubes. The Bijou amplifier board has pin 9, the internal shield in the 6922, grounded to reduce noise. Using tubes with a heater tap at pin 9 will damage the heater biasing circuit and, possibly, cause other problems."
   
  Might be more work that you are expecting.  Good luck.  Be safe!


----------



## Kirnupiima

Oh noes! I have pretty much all of the parts ordered already an now i get to know the amp doesn't do that well with Grados :[
   
  What do I do now? Should have gone with EHHA?
   
  The new HD700s look nice, how would Bijou do with 150ohm phones?
   
  Edit: Solution; get Beyerdynamic Tesla1 and finish the project like a boss! Pictures when it's ready! Could take months though


----------



## vlb

Ivé built my bijou as dual mono with 2 hammond 370 daz.
  Ive done regals mods, increased size of caps in the audio circut and replaced elyts with film caps.
  Ivé also removed the cathode bypas caps and done regals mod.
   
  I know Im only using half of the aviable current from the PS, so the question  is what I should du with the remaining power. I thought of using paralell ecc99s in the output stage to lower zout, but I dont think it makes sense since Im using it as a preamp most of the time, or does it?
   
  Right know Im considering a pretty hot biased 6n30p input stage, but I know  that I will loose gain, and right now I like the amp with full nfb wich barely gives me any gain. Maybe an extra gain stage would do the trick? But I gues I have to add 2 stages if I want to keep the global nfb(?).
   
  Maybe its a better idea to increase gain på loading the 6n30p with a constant current source?
   
  Is there any other tubes I could try as output tubes? Already tried 6n6p but didn´t like it.
   
   
  Im thankfull for any comments on my thoughts and suggestions for mods.


----------



## SBoy

Hi all, i dont have much experience with electrical stuff although I DIY my own bijou. I have a lcd-2 with me and i understand OTL would not drive low imp to full potential.
   
  But i'd like to know whats the power output of bijou at its default configuration? I've tried searching on this forum but did not find anything on output power.


----------



## bryfox86

Hello everyone!! It took me 2 days but I have finished lurking all 266 pages of this thread. 

Let me give you some background on me... I am in the navy and have gone through school for micro miniature electronic repair (m2) I am savvy as far as building one of these goes... 

I am very new to the hifi world. I was completely content with an iPod and Bose headphones till my friend decided it would be a good idea to ruin it all by showing me a Cowon d2 with a fiio e11 on ath-m50... Ruined me forever! Now I want to build one of these!

Can you tell me if this kit is going to be good enough right out of the box or will I want to upgrade it as soon as I turn it on... Can you give me a list of the easiest and most affordable upgrades. I am already planning on using a 370dax and still looking for everything please help this newb to hifi with some advise! Thanks in advance!


----------



## Navyblue

I understand that you are new in this. Nobody can tell you if something sounds good enough for you. If someone is really sure something is good enough for you, be very skeptical. HiFi is not like computers where someone can objectively tells you that this processor is better than the other one. Let your ears lead you, not some random dude's random opinion. But ironically in youth dominated forums like this it is the newbies who have the most to say.
   
  My advice is try to have a listen at the gears yourself if you can, even if you can't listen to everything out there, by referencing with those that you have heard, you *might* be able to guess how the others sound like.


----------



## Fred_com

Hi guys, don't know if this thread is dead or not, but I'll give it a try.
   
  I've read through all the pages, and although I've found answers to most of my questions, I still have some:
   
  1. Is it possible to use Bijou without volume pot? (I'm going to attenuate digitally via Buffalo II).
  2. Earlier in the thread someone was saying that one should turn on\off the amp with the headphones unplugged. Is it just an extra precaution, and not really necessary?
  3. I'm going to use Thunderpants with the Bijou, has anyone tried them or T50rp's? They're 50 Ohm, and it seems that low Z headphones are less preferred, but I can attenuate the NFB to better suit them, right?
   
  Thanks,
  Fedor


----------



## walangalam

I can answer #2 because I recently had a bad experience with it.
   
  During power up, the output capacitor is not charged, and during the 30 seconds or so before it stabilizes, there is DC in the output approx. 60 volts.  This is bad.  If you have headphones connected, they might not immediately burn, but eventually, it will.  
   
  At power down, the same thing happens again - but now the cap is discharging.
   
  Note that this happens on all equipment with an output cap, but this is specially noticeable with high voltage tubes.  I tried it with only an MKP film output cap by removing the electrolytic output cap, it still registers the DC at power up.
   
  In my case, I connected the Bijou to a Pass F5 clone amp, and I noticed at power up a wailing hum from the speakers.  Thats when I found out about the DC when I measured it.  Before I found this out, I always had my HD650s connected during power up/down.
   
  So if you have expensive cans, dont do it!


----------



## Fred_com

Thanks for sharing Walangalam, that's pretty bad indeed. I'll need to remember to unplug the phones then.


----------



## funch

I can speak to your last question, as I have a Bijou (much modified) and mod'ed T50RP's. Bottom line is that the Bijou really does its best work with high-impedence 'phones like the Senn. HD6XX. It will
  drive the T50's, but there are other DIY amps that will sound better with them. The Cavalli EHHA to name one.


----------



## Fred_com

Hi Funch, thanks for reply. Yes, I know now that Senns are the best match for the Bijou, but I have ordered the kit and trafos just after reading first few pages of this thread, not knowing about which HP's is better matched. And now it's too late to go for another build as trafos and kit (thanks Jeff!) just arrived.
  Looks like I will have to buy myself HD650 sooner or later  But EHHA is on the list too.
   
  So I guess only Runeight can answer my first question


----------



## Oberst Oswald

Do not regret buying & building the Bijou.  It is an excellent amp and my favorite among the amps I have built or owned.


----------



## Fred_com

Oberst, I've always wanted to build an all tube amp, and I'm sure I won't regret building the Bijou, I'll just have to do a little headphone rolling


----------



## preproman

Can someone point me to the page on this thread where the Bijou and the EHHA are compared?  Thx.


----------



## Fred_com

preproman, you can use this wonderful tool for searching - http://headfi.qix.it/, this thread is at the bottom.


----------



## Kirnupiima

I thought I'd ask to clarify; on the PSU, C2 does not have a polarity so I can just solder it in place?
   
  I today got all the resistors, diodes and some capacitors in place. Still missing the biggest caps and accidentally bought tube sockets that don't fit the PCBs so have to replace those. ;[
  Finally taking shape, though. I had so much fun today, this is my first DIY project so I propably have to be super careful before introducing it to a power socket.


----------



## Fred_com

That is correct, C2 orientation doesn't matter.


----------



## Kirnupiima

Bought wrong kind of the biggest capacitors ;[ What do you suggest I do if I wanted to still try to mount them on the board? Cut or bend the excess legs and find something to lenghten the + and - to reach the holes? Mosfets are meant to be tightened to the heatsink with a bolt, amiright?


----------



## Fred_com

Yes, mosfets are tightened with a bolt and a nut, but don't forget insulating pad and a plastic washer for bolt (like these). As for the caps - I'd cut out excess legs, insulate the pads, and use some 22 awg cable to connect to the board. And also insulate the connections between caps legs, wire and board with some heatshrink tubing.


----------



## Kirnupiima

Finally got the last remaining parts and connectors. Got everything running today with all tubes glowing nice. The voltage is very low after connecting the amp boards (210VDC) and doesn't get any higher. I'm using EZ80 on the PS and 6n6p-i & 6n11 on amps. Also have a massive hum while trying it with headphones. I suppose the low voltage is to blame and atm messy wiring within the pizza box.
	

	
	
		
		

		
			




   
  I have no additional mods. Pretty much just gathered everything according to the list. Should I try the EZ81 for additional juice?
   
  PS; when are the leds supposed to glow? They don't.


----------



## Fred_com

Sorry for the late reply. 
  Let's try to troubleshoot a little: 
  1. Did you try to load PS with 100K 1W resistor prior to connecting amp boards?
  2. What trafo are you using? Are the ratings correct?
  3. Check mosfet legs for shorts, if there's any, they have to be replaced.
  4. Pictures of fully populated PS and amp boards would help to further investigate the issue 
   
  As for the leds - I myself omitted them (was too lazy to calculate led resistor), so can't help you on this one, maybe double-check the orientation.


----------



## Navyblue

You can not just ignore the other 2 poles of a 4 pole capacitor. 4 pole capacitor has separate input and output leads, 2 inputs and 2 outputs. Do read about them, you most likely won't be able to use them without modification to the PCB.


----------



## Kirnupiima

Quote: 





navyblue said:


> You can not just ignore the other 2 poles of a 4 pole capacitor. 4 pole capacitor has separate input and output leads, 2 inputs and 2 outputs. Do read about them, you most likely won't be able to use them without modification to the PCB.


 
  It says "do not connect" on the two other poles. I humbly obeyed. (at work atm, will check and make sure after.)
   
  @Fred_com,
  1. I did. Got a solid 250V.
  2. R-core  R0080-036B-EU from www.vt4c.com:
   
  100W power transformer Recommend for Single Ended tube power AMP or Mono power AMP.
  Primary 0-220-230-240V
  260-230-0-230-260V 100mA
  0-6.3 3A with CT (I have 6,6V for some reason, measured yesterday. Maybe should try the alternative windings for more accurate V?)
   
  3. Not really sure how to do that if there's some trickery involved.
  4. Will take pictures! After work or tomorrow.
   
  Thanks for the help guys, it was quite a let-down when it didn't function properly. The whole pile is in shambles atm (parts intact on the PCBs ofc, took off the wires). I have to get some more wire to do the wiring properly and neatly to minimize it's effects on the hum.


----------



## Fred_com

Yes, it seems that those additional poles are just for mechanical stability ( panasonic ce tha capacitor datasheet )


----------



## Navyblue

I see, those aren't 4 poles electrolytic.


----------



## Fred_com

Well, transformer is fine then. Did you measure 6.6V with or without the load (i.e. with PS connected)?
   
  As for measuring mosfets for shorts: make sure that capacitors on PS boards are fully discharged (wait 5 minutes after disconnecting power, or check PS output voltage with your multimeter so its 0 volts), then check each of three mosfet legs for continuity between them (if there's any continuity - mosfet is dead).
   
  On the other hand, you've said that PS gave 250V with resistor, so mosfets are probably fine, but check them anyway just to be sure.


----------



## Kirnupiima

Got the EZ81 today and it works! Sorry for not taking the time to take and upload the pictures for troubleshooting. The heater voltage is only 6V (not 6,6V anymore) for some reason and B+ doesn't get higher than 246VDC but it works! No hums of any sort. Leds don't work either but that's not a big deal.
   
  The sound is a bit soft after few hours of uptime and a bit dark compared to what I've used to. This is an experiment with tubes of course so everything is new/old to me. Does is get brighter or more open with time and are there positive effects if the voltages reached the optimals? Any tips achieving those?
   
   

   
  edit: B+ went up to 250 by itself<3


----------



## Kirnupiima

After looking at the wiring diagram again I noticed that I had soldered the volume pot right before the headphone jack and NOT right after the line inputs. Can this cause damage and does it make how big of a difference? I inted to fix it asap but just to learn something for the future I'd like to know. 
	

	
	
		
		

		
		
	


	



   
  edit: I changed the volume pot to it's rightful place and got a huge hum as a reward. It seems to come from the NFB pot and disappears if I connect all the pins from the same channel. Need to investigate and propably get rid of the pot anyway.


----------



## Kirnupiima

I removed the NFB pot and tidied up the star grounds into one shared point as in the wiring diagrams. I also located the source of the hum. It's the transformer and the hum can be heard from half a meter away. I noticed this because of the wooden chess board on which I've kept the pizza box but now the transmormer slipped off the cardboard and began to sing the song of it's people aloud. Is there something I could do about it or is it a lost cause and time for a new one? Please help, I'm so close to finishing the whole project and this pains me so much.


----------



## Koningkip

Hello all,
   
  I'm new to this headphone enthousiasts forum. This is also  my first post here, however i have read this entire thread before and during my own build of the Bijou amp.
  SInce i am new to the DIY scene, i did my homework first. I had already build a phone preamp (from boozehound lab). But a tube amp is something else for sure.
   
  The build wasnt to difficult though, most of my time went into the casing (all wood). And the wiring, since i by mistake ordered and installed the wrong pot for volume. 
  It worked the first time i fired it up, however with to much noise. So when i ordered the new pot i also decided to upgrade the C6 of the amps and do the amphead mod, and upgrade the signal wiring. What a difference!!!
   
  I am now listening to the amp, what a joy!
   
  I am using a Grado 325I headphone (32ohm), i am looking for something that might match better with this amp, maybe the Beyer dt990 (600 ohm).
  My source is a media pc via an arcam Rdac. 
   
  I am using rather standard tubes now, so maybe ill see if i can find some nicer models to upgrade this amp further.
   
  Thanks everyone on this thread to share their knowledge and experience with this amp.


----------



## m11a1

Hello, I am looking to build a balanced Bijou and I was wondering what does everyone use for their balanced volume control? 
   
  I'm thinking the joshua tree attenuator. Does anyone have any insights to which I should really use?
   
  Thanks!


----------



## yiancar

Personally I used an alps attenuator which also has a motor on it. there is also a more audiophile grade model without the motor. Dact is also another choice. This attenuator from part connexion can be taken into consideration. The reason I used the alps one was because it was easier to source and I consider Alps products to be trusted.


----------



## Kirnupiima

Now it's finished! The case is a rather large CO-meter previously used in a power plant. Almost the size of a regular computer case. The buttons on the front panel are pretty and still funcional (they do nothing) and the two displays are just for show.
  The transformer still resonates but it doesn't get mixed into the signal anymore. For some reason I get a hum when connected to the phono pre-amp but not when there's a Nuforce Icon HDP in between.
   
  I did a left-handed solder work to a Regal's mod after the pictures were taken and the change from Chinese tubes to 6DJ8 Bugle boys is quite remarkable! So impactful and not shrouded like it used to be.
   
  Twice when powering it off it's messed up the Nuforce dac for some reason. They share the power socket so maybe there's a spike of some sort that messes up the circuits, dunno.
   
  Now to get some sort of a router or switch to control all the sources and outputs so I don't have to change cables every time I use the Bijou instead of my monitors. Cheers!


----------



## yiancar

nice build  try routing your wires a bit better though


----------



## yuujin

I almost tried to recase my Bijou in an old Sun server. Pity my boss didn't allow me to bring it home.


----------



## Kirnupiima

Quote: 





yiancar said:


> nice build  try routing your wires a bit better though


 
  No need, it's quiet:] There is a bit of extra on the black signal wires but I'm too lazy to even consider opening it again since it's very operational as it is.


----------



## vlb

Im finaly getting around to learn more about tube amplification  Im tying to analyze my bijou but there is one thing (so far) I don´t understand.
   
  How does the value of c1 affect the amp?

 Thanks!


----------



## nikongod

Quote: 





vlb said:


> Im finaly getting around to learn more about tube amplification  Im tying to analyze my bijou but there is one thing (so far) I don´t understand.
> 
> How does the value of c1 affect the amp?
> 
> Thanks!


 
   
  In a "proper" Futterman C1 is part of the positive feedback loop around the cathodyne and output stage. It allows ac at the output to go back into the junction of R5&R6 to create the loop while blocking the DC present at the output of the amp from getting back to the junction.  
   
  In the Bijou R6 and R5 are not sized properly to allow positive feedback to happen (in any meaningful amount anyways) so C1 does basically nothing except block DC. Since the cap does basically nothing, its size is not critical with the part values on the Cavalli site. 
   
  For proper "futterman action" R6 should be much smaller than it is and the global negative feedback resistors should be soldered to the PCB and never removed. No, I don't know how much smaller R6 should be. Yes, there is the very real possibility that you blow up your gear if you go mucking about with R6 and do it wrong BUT this possibility of failure is balanced against the possibility of finding something interesting. 
   
  If the amp had R5&R6 sized properly the cap would need to be large enough (enough capacitance) to pass the lowest frequency you cared about into what may be a lowish impedance. My gut instinct is that 10uF is large enough for preliminary experimentation by anyone inclined to experiment with different values of R6. Since you should not even think about tweaking R6 without measurement tools to verify stability you can very easily measure frequency response and figure out if 10uF is in fact large enough in the end.


----------



## jhawk1729v2

I just finished my Bijou build.
   
Album (with comments) is here.
   
  It sounds great with my HD650s. Better soundstage, detail (it's very crisp) and bass than my Project Sunrise II or O2.


----------



## funch

Very nice build. I also use Auricaps and enjoy the sound quite a bit using HD600/800's.


----------



## yiancar

Experiencing hum in only one channel, balanced setup, psu in separate box. When the amp is on top of the psu i get hum in the left channel (right its fine) when i move them further away the hum disappears, any idea what to do?


----------



## bhjazz

yiancar said:


> Experiencing hum in only one channel, balanced setup, psu in separate box. When the amp is on top of the psu i get hum in the left channel (right its fine) when i move them further away the hum disappears, any idea what to do?


 
 Can you post a few pics?  That might help rule some things out. 
 I'd vote that some ground connection on your left channel has a cold soldered joint somewhere, but it could easily be something else.


----------



## yiancar

the tubes sit on top of the board that's why the extension wires. Also just tried the J1 connection and it didnt work. after the amp is left to complete cool down also the right channel experiences hum, 1-2 minutes powered up and the right channel hum dissapears


----------



## holland

yiancar said:


> Experiencing hum in only one channel, balanced setup, psu in separate box. When the amp is on top of the psu i get hum in the left channel (right its fine) when i move them further away the hum disappears, any idea what to do?


 
  
 Are you using a toroidal, and is it located under the left channel?
  
 Also is your amp chassis grounded to safety ground (earth)?


----------



## yiancar

the trabsformers are r core, there is one under the left channel and one under the right , no the star g is not connected to earth. should i try ampheads mod?


----------



## holland

yiancar said:


> the trabsformers are r core, there is one under the left channel and one under the right , no the star g is not connected to earth. should i try ampheads mod?


 
  
 well, you're clearly getting noise from proximity to the transformers.
  
 you should earth the amp chassis for safety reasons.  what is it connected to, since you're doing star grounding?  the chassis is connected to the source's shield?  and if your amp faults with nothing plugged in, what happens?
  
 you can try ampheads mod.  i use dc heaters only, but i don't think this is relevant.  worth a try any way.


----------



## yiancar

ive connected earth to chassis , noise still there. amohead mod tomorow since i need the resistors, anything else i can try? or my only chance is moving the amp further appart from the psu?


----------



## holland

yiancar said:


> ive connected earth to chassis , noise still there. amohead mod tomorow since i need the resistors, anything else i can try? or my only chance is moving the amp further appart from the psu?


 
  
 earthing the chassis is for safety and grounding issues.  neither is the noise you are talking about.
  
 distance, more or less, if that's what you have it isolated down to.  it's unlikely you'll be able to do anything else except shield your enclosures with mu-metal.  you can try to put a carbon steel enclosure around the transformers to see if it helps.
  
 psu in a separate chassis is generally a sucky idea.  people always try to stack, and some transformers radiate in height more than they do on a parallel plane.


----------



## yiancar

tried everything i could thing of, even a steel sheet (3mm thick) on top of the transformer did not help. any other suggestions ?


----------



## nikongod

Have you moved the tubes from one channel to the other? 
  
 If the hum follows the tubes you have a microphonic tube. Get a different tube to test that it is in fact the problem, then crush the bad tube with a brick. 
  
 While DC heaters will not (usually) set off microphonic tubes they are really just a bandaid for the real problem of microphonic tubes... Fixing the real cause of the issue (the tube) is so much moar better than changing the heater. 
  
 I guess both is sort of nice, but usually so far overkill as to be relegated to commercial amps where its better to have a happy customer with a dodgy tube than an amp that hums out of the box, but only when your customer uses the best tube he owns... Whats wrong with your amp anyways? 
  
 Quote:


holland said:


> psu in a separate chassis is generally a sucky idea.


 
  
 Tubes on long leads is another.


----------



## balderon

Unlikely but wanted to ask. Is it possible some of the hum is from the proximity of the transformer to the power supply umbilical cord? Is it shielded?


----------



## yiancar

nikongod said:


> Tubes on long leads is another.




will check the tubes as soon as i go home, i thought that the extention cable of the tubes may picking up noise i moved the tubes around and i get no difference so i guess i can rule that out. 

i get noise / hum on the left channel ( balanced amp btw) which is not affected by changing the volume. when i move the amp case off the psu case the noise dissapears . i use r core transformers and the transformers are directly below one of the two amp bored of each channel



balderon said:


> Unlikely but wanted to ask. Is it possible some of the hum is from the proximity to the transformer power supply umbilical cord? Is it shielded?





no its not shielded. i cannot understand how noise is picked up only from the right channel, i mean both the psu and amp are symmetrical.


----------



## nikongod

After seeing the quoted passage below I dont think that the long leads are the cause of the issue. 
  
 Quote:


yiancar said:


> i get noise / hum on the left channel ( balanced amp btw) which is not affected by changing the volume. when i move the amp case off the psu case the noise dissapears . i use r core transformers and the transformers are directly below one of the two amp bored of each channel
> no its not shielded. i cannot understand how noise is picked up only from the right channel, i mean both the psu and amp are symmetrical.


 
  
 So when you move the amp away from a device that one could safely assume radiates EMF the noise goes down.
  
 Not much question what is wrong.
  
 Build a long umbilical, like you should have as the only real reason to build an external PSU, and put the PSU 6ft from anything you care about.
 Alternately you could try lining the lid of the PSU with mu-metal foil, but for the cost I would not bother. 
  
 Why one channel and not the other: one of your transformers leaks more flux than the other.


----------



## duncan1

You have certainly tried out a variety of suggestions . In my own design 15W RMS class A  mono-block stereo amp with separate -outboard power supplies[two off] with separate umbilical cords . I have NO hum and thats using standard transformers. In a letter to Electronics World I said that [by experiment] I found that if I lifted the centre tap of the mains transformers so that they werent terminated in the power supply boxes but ran [floated] through   each cord to the star earthing that I had located directly underneath each amps  PCB [for a very short run to star earth for each component requiring a star earth] on the PCB. This worked amazingly well for me and got approval from some EEs in the mag.I do not agree with the point of -external PSs are not as good as internal . That conflicts with my own findings into them as I have found a PS that is not near a power amp is much better for lower noise  / by induction/radiation. You could  if needed separate the star earth return wires from the sensitive input to output by a 10 ohm resistor but they still both go back to the main star earth. I didnt need to do that. I proved this works and up to now nobody has challenged that. But knowing Head-Fi somebody will --as long as they understand/realise it WORKS! I did not need to screen the cable.


----------



## holland

duncan1 said:


> external PSs are not as good as internal . That conflicts with my own findings into them as I have found a PS that is not near a power amp is much better for lower noise  / by induction/radiation. You could  if needed separate the star earth return wires from the sensitive input to output by a 10 ohm resistor but they still both go back to the main star earth. I didnt need to do that. I proved this works and up to now nobody has challenged that. But knowing Head-Fi somebody will --as long as they understand/realise it WORKS! I did not need to screen the cable.


 
  
 They are sucky because people try to stack, which is a really bad reason to do it.  I run external supplies now and then, not PSUs, just the transformer over a longish distance from the amp.  I always have regulation very close to the amp itself.  I run the secondaries in an umbilical.  If you run regulation over long distances, it generally defeats the purpose because the longer the leads the more "stuff" it can pick up along the way, higher resistances, etc. etc.
  
 His problems are not ground loop related.  I always use a ground loop breaker, some say it's due to bad practice, but I like nodes/zones of ground "planes" or loops.  i.e., star ground nodes.


----------



## duncan1

People try to stack them ? If you mean  put them straight on top of the amp. I would have though after posters had been on Head-fi a while they would know that -that is one sure way of causing trouble. You would then be as well without an outboard PS due to closeness of the transformers.and the heat would cause components to overheat and cause instability. Anybody with a bit of common sense would put them on a lower shelf with a foot spacing.  And thats what I did. As far as putting the regulators  on the PCBs all the amps I built had heavy smoothing at the point where the outboard PS contacted the PCB. I am not alone in this some very up market UK designs do the same.If you extend the secondary coil side of the mains transformers via the umbilical cord you then have  a coil circuit that can pick up interference. Whereas if all the rectifiers and regulators  are on the transformer box then the output impedance is much lower with less likely hood of induced/ radiated  pick up >If his problem is not ground related then why have the previous suggestions not worked?  and have you the answer?


----------



## holland

duncan1 said:


> And thats what I did.


 
  
 And that's not what the other poster did (he stacked), and hence the comment, and your reference to it....which is completely tangential.  Read it again.  His problem is that he stacked and is having flux induced noise.  He noted moving the PS section away, the noise went away.  There's not much to discuss.
  
 BTW, white space will make your posts more readable.


----------



## AnakChan

Chaps, I've just cleared up a bunch of off-topic bickering. Honestly if you chaps just can't conduct a mature conversation, please just block each other.


----------



## bhjazz

look at (and reheat, if necessary) Quote: 





yiancar said:


> after the amp is left to complete cool down also the right channel experiences hum, 1-2 minutes powered up and the right channel hum disappears.


 
  
 That's a cold solder joint, pure and simple.  I know I've done it myself.  While you're working through some of the other proximity tests, take some time to look at (and reheat, if necessary) as many solder joints as possible.  Do you have a magnifier?  10x would do it.  Check them all.  
  
 There are multiple things going on with your build.  My suggestion is only a small part of the fix for your original problem, but you'll need it eventually and it will certainly fix your right channel issues.  You've got to start with solid connections before you can get to these other fixes.


----------



## RAZRr1275

Would someone build one of these for me? I'm not looking for one right now but closer to Christmas I'd like to work something out. Feel free to pm me if interested. I will pay of course.


----------



## yiancar

noticed that on one of my psus under load the maximum voltage i can get is ~245v  the other runs fine at 250v sharp. checked input capacitors they are fine
  
 any idea what maybe causing this? can it be the transformer?


----------



## holland

yiancar said:


> noticed that on one of my psus under load the maximum voltage i can get is ~245v  the other runs fine at 250v sharp. checked input capacitors they are fine
> 
> any idea what maybe causing this? can it be the transformer?


 
  
 It might be normal and within tolerance.  Mine is like that too, but I have Regal's mod in it and running 6H30 and 6N6P tubes.  You can reduce the R in the CRCRC filter, and increase C to compensate.  On the other hand, I have thought of using a diode bridge instead and increasing R and C.
  
 I think when I noticed the most drop, my rectifier tube was dropping too much, so I changed it to a fresh tube and it was happy.  That was a few years ago, haven't opened it up since.


----------



## yiancar

got another problem again. i left the amp for quite some time on and one of the channels stop working, i feared it was the tubes so i interchanged them and still got no sound. i measured pin 1 - 2 -3 of the 6dj8 and they were all the same voltage , 184v i panicked . any idea whats causing this


----------



## duncan1

Yiancar- Could only find the original -2007 circuit diagram. If you have 184 V on -1+2+3 then  thats the -plate- grid-cathode- all with the same high voltage. If you have swapped them around  and you still have that fault.It must be the circuit rather than  an internal S/C in the tube. You did try your MM across pins  1+2+3 just to be sure did you? If so then it sounds like the coupling caps have failed[looking at the circuit]  Thats just ONE possibility. There are more.  Check that first.


----------



## yiancar

duncan1 said:


> Yiancar- Could only find the original -2007 circuit diagram. If you have 184 V on -1+2+3 then  thats the -plate- grid-cathode- all with the same high voltage. If you have swapped them around  and you still have that fault.It must be the circuit rather than  an internal S/C in the tube. You did try your MM across pins  1+2+3 just to be sure did you? If so then it sounds like the coupling caps have failed[looking at the circuit]  Thats just ONE possibility. There are more.  Check that first.


 
 measured the the coupling caps (c3 c4) they are fine. also checked pin 1-2-3 and they are not shorted, any other thoughts?
  
 also tried changing tubes. same problem


----------



## yiancar

stupid me... cold connection on the heater pins. thanks for the idea


----------



## duncan1

When my AVO VCM -tube tester went faulty till I fixed it I thought that was a temporary test   Many people have tubes that  are S/C internally its a common problem even with good make tubes. Instead of throwing then all away you could try a high voltage pulse across the S/C this sometimes "blows" the short off. You cant keep doing it as eventually it destroys the elements inside but it is always worth a try. Circuits can be seen on old tube radio repair sites. But due to high voltage can be dangerous to use.


----------



## DutchGFX

Quick question, I just finished my first amp, and was looking for another project. The bijou, having PSU in kit from glassjar, seams like a good option, as I don't have to source a transformer and test for correct voltages and etc. How easy, 1-10 would you rate this build. It looks pretty easy in my opinion, but I wanna get some inout, thanks!

Correction, I would need to buy a $80 transformer, so that's put the build at around $300, would it be worth it at that point as well? I would be driving T1's. Would the Crack be a better option?


----------



## nikongod

dutchgfx said:


> Quick question, I just finished my first amp, and was looking for another project. The bijou, having PSU in kit from glassjar, seams like a good option, as I don't have to source a transformer and test for correct voltages and etc. How easy, 1-10 would you rate this build. It looks pretty easy in my opinion, but I wanna get some inout, thanks!
> 
> Correction, I would need to buy a $80 transformer, so that's put the build at around $300, would it be worth it at that point as well? I would be driving T1's. Would the Crack be a better option?


 
  
 I would lean towards the CRACK - it is better documented and the fact that Bottlehead does all the casework is pretty attractive.
 Plus the CRACK is point to point so you can start to learn how to do that and liberate yourself from the slavery of stuffing a PCB of another person's design. Building your own point-to-point amp is a very rewarding experience.


----------



## funch

I second nikongod in recommending the Crack. Although I've not built or heard one, the build looks to be easy and from what I've read, should sound
 excellent with your high-impedence T1's. Tyll over at Inner Fidelity documented his Crack build on video. Check it out. I have built a Bottlehead Eros
 phono amp, and the documentation/instructions (on CD) are excellent.
  
 As a personal aside, my first kit build (many moons ago) was a Dynaco PAT-4 preamp. Even though it used circuit boards, they were already assembled/
 tested, so it was essentially a point-to-point build. It had very detailed, step-by-step build instructions (like the Eros), that I like to call 'electronic kit building
 for the complete idiot' because it was my first, and it worked first try. 
	

	
	
		
		

		
			





 The trick is is go slowly; read each instruction twice, solder once.


----------



## bhjazz

Three-fer.  Start with a Crack.  My own comments after hearing one a few years back:
  
 "...Dan Schmalle and Queen Eileen: The Crack is amazing.  I'm sure someone would have tackled me at the door, but I really wanted to just run out the door with it and keep it for my own.  I'm sure your mega tape system had a lot to do with the great sounds I was hearing.  Never mind.  The Crack is seriously good for not serious money.  Well done!"
  
 I built a Bottlehead Foreplay in 2001 or thereabouts and can attest to the great instructions.  All the parts are available, everything is ready from the start.  If you get lost, there is a great community supporting just their products.  And if you get stuck after _that_, give Doc B. a shout out.  He'll be able to get you up and running one way or another.


----------



## masesico

hello I want to build a otl amplifier, but I'm undecided between bijou and another amp like this http://www.hificollective.co.uk/pdf/otl_head.pdf
 have different typology but, less high voltage, more choise boutique outputcaps and PS caps, work hell wiht low Z phone, good power and i love the 6080 look, but not have a PS slow start and need a CCS for better stage.
 can someone tell if it is a good alternative or bijou is definitely better??


----------



## ady1989

So I put my amplifier together last night and was powering up the PS as explained by the Cavalli website. The tube lit up but there was heavy arcing/sparking inside the EZ81 tube for a few seconds until it heated up (and then it went away). I was able to adjust the voltage to 250 VDC and it was stable. After a few more tries it seems like the tube finally burned out and I saw smoke. I have yet to take everything apart and look but I should find the evidence. I double checked and triple checked everything, I don't think I made a mistake. Faulty tube perhaps? If anyone knows what this may be please jump in. Needless to say that didn't make me very happy and I had to walk away. The tube heaters for the rest of the tubes worked fine and they lit up. I didn't use the PS to power the amp boards yet.


----------



## yiancar

if you got any high voltage diodes around you can use them instead of the ps tube


----------



## ady1989

I don't have any unfortunately. I guess I will need a new rectifier tube. I think the smoke was the fuse but I can't say for sure until I take everything apart. Would it make sense that if the tube was bad and shorting it would blow the 4A fuse for the transformer? I don't think there is anything wrong with the PS circuitry and I very carefully checked for shorts before powering up.


----------



## ady1989

I took a look at everything and the fuse is intact and nothing seems burnt. It didn't smell like burning components before I powered it off. Resistance in the transformer seems to be the same as before. Something got hot though, probably just rosin burning off. I hope the capacitors are OK but I don't have any way to check. I guess I just need a new rectifier tube. Anyone dealt with a bad tube that's arcing and sparking and popping inside? I'd love any input!


----------



## bhjazz

Do you have a multimeter?  That would be the best way to check the caps, although remember when you do this that:
 a) they may still have significant charge left
 b) the rest of the circuit can affect the results you see.  
  
 First, is your zener installed in the right direction?  
  
 Also, I know you've double checked more than once, but walk through the circuit diagram and review all your resistors: their locations are important.  For instance, there is a 30.1k and a 301 ohm.  They're easy to misplace on the board!  Likewise, review your caps, too.  There is a 470u and a 47u.    
  
 The answer is in there somewhere.  Good luck and stick with it!


----------



## ady1989

Thanks for the tips, but it's fixed and running! It was a bad rectifier tube after all. Too much triple-checking went on to install something wrong. I'll update the DIY log thread if you want to have a look. I'm pretty darn happy except the case gets way too hot with the top cover on. I'll have to figure something out in the future. Now, for some classic rock and that beer


----------



## vlb

My power supplie's (almost) finished 
 http://s13.postimg.org/etvcepmp3/2013_12_27_082.jpg
  
  
 There's a power switch in the electrical inlet connector, but do you think it would look better with a power switch in the front? If so any suggestions?


----------



## funch

I use this one, which allows you to switch the heaters on first, then the B+.
  
 http://glass-ware.stores.yahoo.net/acswitch.html


----------



## bhjazz

vlb said:


> My power supplie's (almost) finished
> http://s13.postimg.org/etvcepmp3/2013_12_27_082.jpg
> 
> 
> There's a power switch in the electrical inlet connector, but do you think it would look better with a power switch in the front? If so any suggestions?


 
  
 Probably depends on how often you would use it.  For my own builds, I like the switch on the back.  Your own visual design will probably be different!  
  


funch said:


> I use this one, which allows you to switch the heaters on first, then the B+.
> 
> http://glass-ware.stores.yahoo.net/acswitch.html


 
  
 I like that very much.  What a great find!


----------



## vlb

Can anyone explain how the pase splitter (V1B) is biased?
 Is the plate voltage of V1A a few volts lower than the cathode of V1B?


----------



## vlb

Time for another question.
 Im using my bijou both as preamp and headphone amp. I dont think the 120uf cap should be used for a line load because of the low cutoff point.
  
 Is this circut a good solution? Can I feel safe operating the red switch with the amp turned on?


----------



## yiancar

Suddenly one channel stopped working:S
  
 The problem is around the ecc99 circuit. Pin 1,2,3 of the ecc99 measure ~220v were pin 3 should have been ~120v. Pin 8 of the tube is at 0v instead of 2.2v. I changed the tube with a working one and still the same. Any idea which component might have failed?


----------



## vlb

yiancar: I would start checking d1-d6. Use the dvm:s diode test function to test each diode for connection/correct voltage drop, with the amp turned off


----------



## yiancar

Stupid me one of the heaters of the ecc99 was not connected...


----------



## LV26

Hi,
 Could you advice me what fuse I should use for powering from 220 VAC?
 I think 0.3A will be good...
 Like this
 http://www.digikey.com/product-detail/en/5TT%20300-R/507-1287-ND/1009059
  
 Or need I use fuse with lower current limit to be on the safe side?
  
 -- Thanks
 Victor


----------



## vixr

I used .250A on mine with 110 mains. It will blow if you havent turned the amp on for awhile...I guess the big caps are hungry after sitting...


----------



## LV26

Hi
 Thank you for the answer.
  


> It will blow if you haven`t turned the amp on for awhile


 
 I think you use fast fuse.
 I specially choose slow (time lag) fuse.
  
 -- Regards,
 Victor


----------



## LV26

Hello all
 I`m starting my Bijou build.
 Now waiting for kit from Glass Jar, custom power transformer (Hammond with delivery to Ukraine is very expensive for me), spare tubes, etc.
  
 Meantime I`m reading 138 of 271 page of discussion. I not read so much before on forums....
 Need lot of beer 
  
 My BIG thanks to all
  
 -- Regards,
 Victor
  
 P.S.
 Sorry for my English (English isn`t my native language)


----------



## LV26

Hi
  
 What about using guitar/instrumentation cables for IN and OUT wiring (I have some Sommers SC-SPIRIT XXL)?
 Or twisted wires better?
 I decide place IN (RCA) and OUT (1/4") at rear panel for aesthetics "look and feel".
 Black steel case (closed style, all inside) with walnut left and right panels. Only Volume, NFB and power LED on front.
 So input wiring can be relatively long.
 I`ll be glad to read yours comments.
  
 -- Regards,
 Victor
  
 P.S.
 I can show my board`s placement idea at monday.


----------



## bhjazz

Victor, 
  
 You wiring will be fine, but you will want to run pairs of that single-strand wire from one location to the other, so just twist two together.  That will help reduce crosstalk and induction.  
  
 And don't worry about your English - it's just fine!  
  
 Brian


----------



## LV26

bhjazz said:


> ...
> You wiring will be fine, but you will want to run pairs of that single-strand wire from one location to the other, so just twist two together.  That will help reduce crosstalk and induction.
> 
> ...
> ...


 

 Hello,
 Thank you for the answer.
 I would like to notice that I`m going to use shielded (coax) cable for signal wiring (RCA --> ALPS --> PCB, PCB --> 1/4" Headphone Con.).
  
_SOMMER CABLE - SC-SPIRIT XXL_ http://sommercable.com/2__produkte/2__030_meterware/2__300_0071.html
  
 IMO coax provide better shielding than twisted pair. (I`m electronics engineer, but design digital devices)
 But probably some voodoo stuff there in Analog World..... 
 Am I correct? I`m about shielding, not magic 
  
 -- Regards,
 Victor


----------



## bhjazz

lv26 said:


> Hello,
> Thank you for the answer.
> I would like to notice that I`m going to use shielded (coax) cable for signal wiring (RCA --> ALPS --> PCB, PCB --> 1/4" Headphone Con.).
> 
> ...


 
  

  
 I really like your comment: I'm about shielding, not magic!  That was great!
  
 OK, I see what you are saying.  I did not look hard enough at the description of the cable.  You should be fine with that cable.


----------



## LV26

Hi
  
 Thanks Bhjazz
 Sometimes I`m ironic. 
	

	
	
		
		

		
			




  
 My preliminary placement. (Only B+ and Heater wiring shown)

  
  
 -- Regards,
 Victor
  
*P.S.*
_Just arrived 6x 6N6P (NOS, 1978 year, Made in USSR)_
_Need some work with ink eraser for cleaning pins._
  
*P.P.S.*
_What Vishay/Roederstein capacitors better - MKT1822, MKP1839 or MKT1813?_
_I read that `1813 very good for audio application... Better than WIMA._
_Is this true? What you can recommend?_
  
*P.P.P.S*
_Sorry I`m not correct (I must indicate WIMA part number)._
_Really,  WIMA MKP 10 have the best __tan__





 comparing VISHAY part`s listed above._


----------



## bhjazz

Victor, 
  
 In your reading of this thread, you'll find some information about noise that might come from the transformer.  Keep this in mind when designing your layout.  I don't think this particular transformer is much of a problem, though, so you should be fine with your current layout.  Just make sure you leave enough room for the output wiring, and also draw in where you want your headphone output on the front panel so you don't forget it!
  
 I don't know a lot about the MKT1813, so it is difficult to help you with that.  They don't appear to be available here in the US.  I have heard that the MKT1822 is quite nice.  I think Google will have to help you!
  
 When you get to wiring the tube sockets for your 6N6P tubes, just make sure you look at the correct diagram on the Cavalli Audio website.  There are different schematics for 6N6P (ECC99) and 6N6Pi tubes.  We don't want you to blow anything up!
  
 Have fun!

 Brian


----------



## LV26

Hi,
 Yeah, I study all Cavalli web and read ALL thread from post #1 
 It was really hard pleasure (but pleasure )
  
 Thank you for precautions!
  
 -- Regards,
 Victor
  
 P.S.
  


> bhjazz
> ... Just make sure you leave enough room for the output wiring, and also draw in where you want your headphone output on the front panel so you don't forget it!...


 
 Output (1/4" Neutrik) will be placed on Rear. Yes... on rear 
	

	
	
		
		

		
		
	


	



 Only Volume + NFB + Power Led on front.


> bhjazz
> 
> ...There are different schematics for 6N6P (ECC99) and 6N6Pi tubes....


 
 Not sure ... I think* "There are different schematics for ECC99 and 6N6P (6N6PI) tubes"* is correct.
 Because different heater pinout/wiring.


----------



## LV26

Hello,
 I have possibilities to buy some tubes for V1 rolling.
 Any positive info about using this tubes with Bijou?
  
 1) E88CC Tesla GOLD pins
 2) E88CC Tungsram
 3) E88CC Philips GOLD pins
 4) E88CC Telefunken GOLD pins
 5) 6DJ8 Sylvania Military JAN
 6) PCC88 Tungsram (not sure - need 7V heater voltage)
  
 -- Regards,
 Victor
  
*P.S.*
 From Regal's Mods
 http://www.cavalliaudio.com/diy/bijou/main.php?page=regalmods
_"Regal's mods requires using ECC99s (not 6N6Ps) and the EZ81 Power Supply."_
  
*Sorry, I can`t understand why 6N6P tube can`t be used with Regal`s Mod.*


----------



## bhjazz

I believe the 6N6P and ECC99 are closely related, but have different heaters, although...don't they have the same pinouts?  I will have to look in to this tonight at home!  Wait - I just saw this on the cavalliaudio site:
  
 "The ECC99 is based on the Russian 6N6Pi. The tubes are similar except that the 6N6Pi has sligtly lower plate resistance (higher current for a given operating point) and ECC99 uses pins 4,5 and 9 for its heater while the 6N6Pi uses only 4 and 5. Nevertheless, these tubes are close enough in performance to substitute the 6N6Pi for the ECC99. The Bijou amplifier board is equipped with configurable heater connections for the ECC99 socket so that 6N6Pi can be used."
  
 So I was actually pretty close.  Yay!
  
 Anyway, back on that site, I just wanted to point out that there is different wiring for the ECC99 and 6N6Pi even though I suggested otherwise.  
 https://www.cavalliaudio.com/diy/bijou/main.php?page=wiring 
  
 Be safe!!


----------



## LV26

Hello,
 My custom-made power transformer arrived today... 20 Eu only 
	

	
	
		
		

		
		
	


	



  

  
  
 Some tech. info
  
 OD: 115 mm.
 ID: 40 mm.
 H: 40 mm.
  
 ~ 80 VA nom.
 Primary: 220 VAC
 Secondary_1: 260 VAC 0.1 A (used AWG 28 equivalent)
 Secondary_2: 260 VAC 0.1 A (used AWG 28 equivalent)
 Secondary_3: 6.3 VAC 4.0 A (used AWG 17 equivalent)
 Electrostatic Shield
  
 Some test measurements:
 DCR(pri) = 16.21 R
 DCR(sec1) = 34.764 R
 DCR(sec2) = 33.564 R
 DCR(sec3) = 0.07 R
  
 I will test under load later. (It is necessary to find appropriate resistors)
 Bingo! 
	

	
	
		
		

		
		
	


	



 Will use light bulb`s for 260 V testing (20-25W, 220V rated - two in series)
  
 To be continued....
  
 -- Regards,
 Victor


----------



## bhjazz

Wow, custom transformer.  Cool!  Great price as well.  Good job!  How did the load testing go?


----------



## LV26

Hello,
 Thank you for the answer.
 Testing under full load not performed at this moment.
 I have some life outside Bijou (work, family, kids, etc.) 
	

	
	
		
		

		
		
	


	



 I hope I`ll have some time at Monday....
  
 -- Regards,
 Victor
  
 P.S.
_I purchase two NOS (from spare part kit from old medical equipment) TUNGSRAM E88CC for tube rolling. _
_It is interesting to me to compare with modern JJ E_CC88.
  
 P.P.S.
_I use GRADO SR80i and I really like this HF._
_And today I findout that Bijou is not best choice for GRADO`s._
_I am a little bit afflicted that SR80i and Bijou are not "best friends".
	

	
	
		
		

		
		
	


	


_
_But I will continue with my Bijou in any case. I promise. 
	

	
	
		
		

		
		
	


	


_


----------



## bhjazz

Victor, no, Grados do not seem to be a great match for this amp.  I just noticed that they were listed in your profile.  You may be able to adjust the feedback a bit to coax some better sound out of them, but this does seem to have better synergy with high impedance phones.  Might be time to consider the HD650!  
  
 Also to note: I built a Cavalli Kan Kumisa III amp a few years back and it seems to do really well balancing between high and low impedance phones.  Maybe you could build that one once your Bijou is complete.  (Yes, I know, DIY is an endless journey)
  
 Cheers!
  
 Brian


----------



## Kirnupiima

> P.P.S.
> _I use GRADO SR80i and I really like this HF._
> _And today I findout that Bijou is not best choice for GRADO`s._
> _I am a little bit afflicted that SR80i and Bijou are not "best friends".
> ...


 
 I had the exact same realization  Went and bought some Beyerdynamic phones right after.


----------



## LV26

Hello,
 Yes, Bijou should be much better with Hi-Z Headphones...
 But I read good response about Grados+Bijou


> adamus
> 
> _I didnt like lowZ phones with the bijou, Purely personal taste but the magic with phones such as the hd650 or the high z Beyers just seemed to go when i tried grados and akg k701. To be honest i was pretty repulsed by the grado bijou combo! However, it is my amp of choice with the senns, really nice sound._


 
 // post #3445
 http://www.head-fi.org/t/277541/bijou-all-tube-futterman-headphone-amplifier/3435
  
 But I think to start collecting money for HIZ Headphones (HD-650 or other with open cans) 
	

	
	
		
		

		
		
	


	



 (I hope that my wife is not reading this forum. 
	

	
	
		
		

		
		
	


	




)
  
 -- WBR
 Victor


----------



## LV26

kirnupiima said:


> I had the exact same realization  Went and bought some Beyerdynamic phones right after.


 

 Hello,
 Thanks for the answer.
 What Beyer`s can you recommend?
  
 -- Regards,
 Victor
  
 P.S.
*Very BIG discount for AKG Q701 at amazon.com*
  

List Price:$479.00Price:$199.99  & *FREE Shipping*. You Save:$279.01 (58%)


----------



## Kirnupiima

To accomodate Bijou's high output impedance you'll basically want 250ohm or 600ohm variant from either DT880, DT770 or DT990 models based on sound preference. My personal pick would be DT880.
  
 Or go with Tesla 1 (always 600ohm) like I did because I do stuff like that on a whim 
	

	
	
		
		

		
			





 
  
 Have fun with the project!


----------



## LV26

What DT`s you use (600 Ohm)?
 Tesla very cheap for me, OMG 
	

	
	
		
		

		
		
	


	



 I joke... I want more $$$ from my boss! Or change company where I work...
  
 -- Regards,
 Victor


----------



## bhjazz

lv26 said:


> (I hope that my wife is not reading this forum.
> 
> 
> 
> ...


 
  
  


lv26 said:


> I joke... I want more $$$ from my boss! Or change company where I work...
> 
> -- Regards,
> Victor


 
  
 LOL!
  
 It seems you are in the same world as us in the states.  These things are all too familiar!


----------



## LV26

Yeah...
 All humans are similar.
  
 I was in USA year ago. Boston - Detroit - LA - SF - (around Bay Area)
 Nice country, nice peoples!
	

	
	
		
		

		
		
	


	



  
 -- Regards,
 Victor


----------



## bhjazz

Victor!
  
 Did we lose you to the shopping bug?  Hope your build is going well.  Let me know if you are getting all the parts you need!
  
 Brian


----------



## LV26

Hello,
 I`m OK. Just collect all parts (from tubes to screws).
 Heatsinks was missed and reordered at Digi
 + some MOSFETS ordered too.
  
 STM STP7NM50N, much better IRF820 - very low Rds 0.78 Ohm.
 IRF820`s Rds is 2.6 Ohm. BTW IRF820 is a obsolete (as I know).
  
 Case drawing done (basically modification for semi-custom case).
 I`m totally rethinking about chassis. Will do "open tube" design 210 x 290 mm. only (A4 paper format)
  
 I will finish with transformer testing today.
  
Preliminary:
  
*Without Loads:*
  
_U(sec1) = 274-276 VAC
 U(sec2) = 275-278 VAC
 U(sec3) = 6.78 VAC_
  
*With Loads:*
  
_U(sec1) = T.B.D.
 U(sec2) = T.B.D.
 U(sec3) = 6.33 VAC @ 4.22A (Rload = 1R5)_
  
 -- Best Regards,
 Victor
  
P.S.
  
*Transformer test result:*
  
 Tested with HP 3457A bench multimeter
  
*Under full load`s (simultaneously):*
  
  
_U(sec1) = 267.3 VAC @ 108.4 mA (Rl = 2.4664 kOhm)
 U(sec2) = 263.6 VAC @ 106.7 mA (Rl = 2.4688 kOhm)
 U(sec3) = 6.23 VAC @ 4.22A (Rl = 1R5_)
  
 I think 3.7 V delta between HV channels is not a problem 
	

	
	
		
		

		
		
	


	



  
*6.3V Load*
 3x 0.5 Ohm 25W resistors (serially connected)
  
 Photo:
  

  
*HV load`s*
  
 12x 3.3 kOhm, 2W (NOS USSR OMLT-2 type 
	

	
	
		
		

		
		
	


	




) resistors "cluster"
 Each "cell" combined from 4x 3.3 kOhm resistors in parallel connection.
 3x "cells" connected serially.
  
 Photo:


----------



## bhjazz

Homemade test loads - Very DIY!  I like it.
  
 I can't find the STP7NM50N in a quick google search, I think the part is not available here.  Have fun with that one.  The IRF820B is what was listed at Cavalliaudio.com, but the major suppliers seems to have many other variations of that one.  Confusion!
  
 I'm glad to hear things are coming along well.   Have fun and enjoy the journey!


----------



## LV26

Hello,
 I`m going to assemble power supply today. All components delivered.
 STP7NM50N available at Digi-Key
 http://www.digikey.com/product-search/en?lang=en&site=us&vendor=0&WT.z_cid=ref_findchips0311_dkc_buynow&mpart=STP7NM50N
  
 Regards, Victor


----------



## LV26

Hi.
 1-st step complete 
	

	
	
		
		

		
		
	


	



  
 Power supply done.
 Now will test with 100 kOm load for some hours.
STP7NM50N`s work well.
 Will continue Monday. Need wait for case.
  
 -- Regards, Victor


----------



## bhjazz

Many thanks for the link to the STP7NM50N.  I'll grab a few!


----------



## LV26

Hi,
 Some additional info:
  
 Some P/N for MOSFET-N with lowest Rds
 (but cost more)
  
 1) IXYS IXKP24N60C5M (not on stock)
 2) Fairchild FCPF9N60NT (available)
 3) STMicro STP11NM50N (available)
  
  
 -- Regards, Victor
  
*P.S.*
_Use www.findchips.com for part search._
_Very nice search engin_e.


----------



## LV26

Hello,
 All board stuffed.
 Some pictures (sorry for quality), will upload better photos soon.
 Still waiting for case. I think all will be finished next week.
  
 Regal`s mod used, R2 socketed with machined golden contacts from disassembled DIP-16 chip socket (SAMTEC).
 http://www.digikey.com/product-detail/en/110-93-316-41-001000/ED3316-ND/14041
  
 Also Mill-Max have a lot of nice sockets (but DIP sockets cheaper)
 http://www.digikey.com/product-detail/en/0255-0-15-80-30-84-04-0/ED1121-ND/3516731
  
 AMP boards LED circuits not used (I`m try avoid additional noise from rectifying diode 
	

	
	
		
		

		
		
	


	




)
  
 All parts soldered using STANNOL 0.5 mm. (Pb free)
 Sn 95.5
 Ag 3.3
 Cu 0.7
  
  

  
  
  

  
 == Best Regards,
 Victor


----------



## Kirnupiima

Beautiful soldering! I should also flip the components to the others side so I could then display the tubes in the open air, regret not doing that in the first place.


----------



## LV26

Thanks, Kirnupiima
 I like solder 
	

	
	
		
		

		
		
	


	



  
 My first idea was place boards into closed case (more safe).
 But my friends recommend me use open air style.
 After some hard thinking I agreed with it 
	

	
	
		
		

		
		
	


	



  
 -- Regards,
 Victor


----------



## LV26

Hello
 Some useful info.
  
 Just receive ALPS RK27 Terminal PCB Board for Bijou volume control.
  
 http://www.ebay.com/itm/171258426056?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649
  
 Nice price, quality and fast delivery.
  
 Photo with RK27 (I solder RK27 on opposite PCB side for some reason)

  
  
 -- Regards, Victor
  
*P.S.*
*Be carefully!*
*This PCB adapter have a common ground between L and R.*
*So ground loop available! Probably I will do some works with Dremel tool for splitting ground on this PCB.*
  
_*After some thinking I decide NOT use this adapter for Bijou.*_


----------



## LV26

Hello,
  
 Any noise issues with LED`s mounted on AMP boards?
  
_Or better to use separate full-wave rectifier (with 100-1000 uF capacitor) conne__cted with heater 6.__3V?_
  
 -- Regards, Victor


----------



## bhjazz

Victor, I haven't seen anything specific about having the LEDs on the amp boards.  That would be a good question for runeight (Alex), however.  Most builds, if done correctly, seem to be very quiet.


----------



## LV26

Hello,
 Thank you for the answer.
 Will test with on-board LED circuit first.
  
 Some photos with good quality
 http://postimg.org/gallery/akdzaesm/
  
 Case arrived, but my case mfg. make some mistakes.
 Need rework 
 I hope new case will be at my bench next week.
  
 -- Regards,
 Victor


----------



## balderon

Victor, FWIW I chose to install LED's under the power supply and amp tube sockets using the heater for power. No issues whatsoever.


----------



## LV26

Hello,
 Thank you Balderon.
 As I understand you place LED`s in central hole of tube socket`s for illumination.
  
 -- Regards,
 Victor


----------



## bhjazz

Victor - nice photos.  Good, clean work!  I see you socketed R2.  You must be thinking about the Regal mods 
  
 Yes, many people do put LEDs under their tubes for illumination.  Just don't use the LEDs that automatically scroll through the colors: Someone did that a few years back - he said it made him crazy in under five minutes!


----------



## LV26

bhjazz said:


> Victor - nice photos.  Good, clean work!  I see you socketed R2.  You must be thinking about the Regal mods
> 
> Yes, many people do put LEDs under their tubes for illumination.  Just don't use the LEDs that automatically scroll through the colors: Someone did that a few years back - he said it made him crazy in under five minutes!


 

 Hello,
 Regal mods was used from beginning.
 No, no...
 I`m very old for using multicolor LED`s.
	

	
	
		
		

		
			




 Only one orange LED will be used on front panel.
  
 Just receive Bijou labels.
 2 layer plastic (black+silver) laser engraved
  

  
 No idea which label place on the case ... I like all 
  
 Funny "warning" stickers (hand painted - DIY) 
	

	
	
		
		

		
		
	


	



  

  
  
 -- Regards, Victor


----------



## bhjazz

Cool labels, Victor!  You wont know which one to use until you get the front panel mostly done (if you ask me).  Where did you get them done?
  
 Where do you plan to place the high voltage warnings?    Fun stuff.


----------



## LV26

bhjazz said:


> Cool labels, Victor!  You wont know which one to use until you get the front panel mostly done (if you ask me).  Where did you get them done?
> 
> Where do you plan to place the high voltage warnings?    Fun stuff.


 

 Thanks Bhjazz.
 I order "Bijou" labels at local company that provide laser cutting.
 Like that http://www.ponoko.com/laser-cutting
 I think google can help you find company near you.
  
 But really my labels have a "cheap" appearance (I spent only 3$ for 5 labels)
 Probably I will do experiment with Dremel tools and aluminum plate (engraving)
  
 Skulls labels.... I think will be inside case. 
	

	
	
		
		

		
		
	


	



  
 -- Regards,
 Victor


----------



## vixr

...


----------



## LV26

vixr said:


>


 

 ???


----------



## nikongod

vixr said:


>


 
  
 +1
  


lv26 said:


> ???


 
  
 !!!


----------



## vixr

nikongod said:


> +1
> 
> 
> !!!


 
 Better to remain silent and be thought a fool than to speak and to remove all doubt... I just removed another dumb post.


----------



## LV26

In progress


----------



## bhjazz

Victor - you're really moving along.  Neat!


----------



## bhjazz

Just ran across a decent site for stranded, cloth-covered 600v wire.  They sell 10', 50' and 100' lengths of 20awg and 18awg.  It looks like 50' of 20awg is only $16.  At least that's what ends up in the cart.  
  
 Anyway, if anyone is looking for MORE WIRE, this looks like a nice deal. 
  
 http://www.radiodaze.com/category/397.aspx


----------



## LV26

Hi
 Nice wires...
 But I can`t wait for delivery.
 I want to finish Bijou ASAP 
	

	
	
		
		

		
			




  
 For B+ I use custom cable (acoustic cable + fiberglass isolating tube)
 1st on photo
 2nd - heater wires (2x twisted AWG -20 in shield)
 3rd - chassis ground (Like 1st without white fiberglass tube)
  

  
  
 -- Regards,
 Victor


----------



## funch

bhjazz said:


> Just ran across a decent site for stranded, cloth-covered 600v wire.  They sell 10', 50' and 100' lengths of 20awg and 18awg.  It looks like 50' of 20awg is only $16.  At least that's what ends up in the cart.
> 
> Anyway, if anyone is looking for MORE WIRE, this looks like a nice deal.
> 
> http://www.radiodaze.com/category/397.aspx


 
  
 That's the wire I used for the B+ on my Bijou. I used shielded SPC for the heaters, FWIW.


----------



## bhjazz

I was thinking about the shielding long after I had shut off my machine last night.  Where did you get your shielded SPC? 
  
Thanks!


----------



## funch

John's Teflon shop on ebay.


----------



## LV26

Hello,
  
 I use two wires cutted from old PC power supply unit (AKA "silver box)".
 I twist 2 wires and place into shield (removed from other cable - coaxial or shielded RG45)
 Finally I place twisted wires with shield into fiberglass tube.
 (2nd cable on my photo from post #4113)
  
 Now I have a nice cable without waithing and $$$.
  
 I think Funch talk about:
http://www.ebay.com/itm/Audiophile-Cable-Mil-Spec-Silver-Shielded-M27500-20SC2S014Teflon-/331178088669?pt=US_Audio_Cables_Adapters&hash=item4d1bc098dd
  
 Regards,
 Victor
  
 P.S.
 I decide to use shielded heater cables starting my Bijou build.
_*Only one end of cable must be connected with chassis ground.*_
  
 All case work DONE 
	

	
	
		
		

		
		
	


	



 I`m on finish. But short timeout because holidays.


----------



## funch

Actually, it's this.
 http://www.ebay.com/itm/10-20-AWG-Shielded-Silver-Teflon-Wire-Coax-/380885022546?pt=US_Audio_Cables_Adapters&hash=item58ae843752#ht_139wt_1242
  
 The wire you linked to should work just fine.
  
 I didn't connect the shielding on mine, and it's still dead quiet.
  
 Here's an underhood pic of mine. I had to use a separate heater transformer, since the 6H30 input tubes heaters draw more current than
 the stock transformer could handle. The two thick twisted green wires coming from the left are the heater wires. The heater transformer I chose
 is 6A. I probably should have used a 4A, as I had to use a 10W resistor to bring the voltage down to 6.3V.  
  
 http://www.head-fi.org/g/i/1014036/a/39075/bijou-highly-modified/


----------



## LV26

Hello, Funch
 Very interesting and original build.
 I hope the sound is a simply perfect!
  
 -- Regards,
  
 Victor


----------



## nikongod

When are you going to put it in an enclosure? 
  
 Why use a 6H30 for input tube? 6DJ8 has lower input capacitance by a factor of about 4.
  
 How many volts is that 10W resistor?


----------



## funch

Are your questions for LV26 or me?


----------



## nikongod

funch


----------



## funch

In order:
  
 It's in an enclosure. Hammond base w/cage.
  
 Early in the Bijou thread, one of the builders (can't remember whom) tried and liked the 6H30 as an input tube. I tried
 it and like it also better than the stock Russian one from Glassjar. It's listed on Alex's site as an alternative. I've tried
 a 6DJ8 but still like the 6H30 better.
  
 The big resistor was neededd to bring down the heater voltage. I selected a 6.3V/6A Hammond transformer, but probably
 should have gone with one rated at 4A.


----------



## Johnthurston

I'm thinking about casing options for a Bijou, specifically the power supply, and even more specifically heat management. It looks to me like the big-power items are the rectifier tube, mosfets, and a couple of power resistors.  I'm expecting to place the EZ81 in open air, but want to make sure I'm providing sufficient sinking and dissipation for the rest of the components.
  
 With 6922 and 6N6P tubes, can anyone give me an idea of how many watts I should expect to be dissipated by:
  R7 and R8
  Q1 and Q2


----------



## LV26

Hello
 There are many Bijou builds with "close case" style.
 I think without any problem`s.
  
 -- Regards, Victor.
  
P.S.
 You can use different MOSFET with lowest Rds(on)
 and bigger heatsinks
  
 See link for MOSFET`s replacement
 http://www.head-fi.org/t/277541/bijou-all-tube-futterman-headphone-amplifier/4080#post_10375065
  
P.P.S
 If you really need this
 Use
http://www.cavalliaudio.com/diy/bijou/images/250VBijouPSVoltages.gif
 and calculate power P=Ur^2/R for resistors. For MOSFETS similar, but you need measure current with load (AMP boards) attached.
 (simplest way). Or use MOSFET datasheet and findout Rds for given "operation point" of MOSFET. Or use SPICE simulator.


----------



## LV26

Hi
  
 My Bijou done!
 Amazing sound.
 Need listen more... need some tube burning (50 hours I think)
  
 Will inform later.
  
   


  

  

  
*THANK TO ALL WHO HELP ME WITH THIS AMP!!!*
  
 Bulk photos:
 http://postimg.org/gallery/4b4au5w6/
  
 == With Best Wishes
 Victor


----------



## ev13wt

Very nice work!!!! Looks really nice!


----------



## LV26

ev13wt said:


> Very nice work!!!! Looks really nice!


 
 Thanks
 BTW - open design for my build was your idea!
	

	
	
		
		

		
			




  
 -- Regards
 Victor


----------



## bhjazz

Victor - That's a nice-looking build - Congratulations!  Hope it sounds great.  Keep us informed as it gets burned in. 
  
 Brian


----------



## ev13wt

lv26 said:


> Thanks
> BTW - open design for my build was your idea!
> 
> -- Regards
> Victor






It looks very nice, I like being able to see the tubes when it gets dark it will glow nicely.


----------



## hey-cameron

Anyone ever try the Bijou with AKG K1000s? Have any comparisons to other K1000-friendly amps?
  
 Cameron


----------



## Johnthurston

I'm making progress on my Bijou 
  
 The power supply was finished a few days ago and is comfortably driving a test load. I had a few hours of depression when all of the AC input was perfect but I wasn't able to detect any output from the power supply. But after stepping away from the bench for a bit, I realized I had neglected to switch to DC when measuring the output 
	

	
	
		
		

		
		
	


	



  
 The amplifier boards are built and have received a quick cleaning. Next up is wrapping them in a basic case and wiring them up for a smoke-test.
  
 I'm currently thinking about a bleed resistor for the power supply. I know that some folks will permanently install a high-value bleed resistor and accept the steady power-loss during normal operation. Is there a reason not to incorporate a bleed using a DPDT mains-switch? If the switch is rated for +250v, use one pole to switch the hot line of the mains to the power supply and the other pole to connect the bleed resistor to ground (on the opposite throw, of course). My thinking is I can achieve both a fast bleed and low power loss with a minor complication in wiring.
  
 Now that I've written that, it dawns on me that I may not be able to find a switch rated for +250vDC (even at the low current it would be seeing).


----------



## LV26

johnthurston said:


> I'm making progress on my Bijou
> 
> The power supply was finished a few days ago and is comfortably driving a test load. I had a few hours of depression when all of the AC input was perfect but I wasn't able to detect any output from the power supply. But after stepping away from the bench for a bit, I realized I had neglected to switch to DC when measuring the output
> 
> ...


 
 Hello, *Johnthurston*
  
 My congrats with progress on Bijou.
 I just finished my build way 
 I think you will be happy with buid and sound 
	

	
	
		
		

		
		
	


	



  
 I can`t understand why you need bleed resistor. For safety reason?
 With 100k resistor you need some minutes for discharge PSU.
 250/100k = 2.5 mA.
 If you choose 10k for fast discharge (for example) you will have extra 25 mA load for PSU.
 And you can have a problem with Regal Mods.
  
 +
  
 Good engineering practice is using DP mains-switch for break *two* AC lines.
 I think some safety standards request this as mandatory.
  
 I not sure that bleed resistor is a good idea.
  
_Everything should be made as simple as possible, but not simpler._ _//_ _Albert Einstein_



 So.. don`t complicate 
	

	
	
		
		

		
		
	


	



  
 -- Regards,
 Victor


----------



## Johnthurston

> ... I can`t understand why you need bleed resistor. For safety reason?


 
 It isn't so much a question of 'need' as of 'want'. I can't see any reason to leave those caps charged if it is simple to discharge them.
 Sure, I can look around for a suitable resistor every time I open the case, but it seems simpler to just build it in and be done with it.
  


> With 100k resistor you need some minutes for discharge PSU. 250/100k = 2.5 mA.
> If you choose 10k for fast discharge (for example) you will have extra 25 mA load for PSU.
> And you can have a problem with Regal Mods.


 
  
 Which is why I was hoping to have the bleed connected only when the amp was switched off.
  


> Good engineering practice is using DP mains-switch for break *two* AC lines. I think some safety standards request this as mandatory.


 
 Can you offer any of those safety standards for reference?
  
 I'm in North America where I'm working with single-phase 120VAC. In my polarized, grounded, NEMA-15 outlets, the ground lead is at the same potential as the 'neutral' lead. Using a double-pole switch on the mains (to disconnect both the 'hot' and the 'neutral') is going to leave exactly the same potential exposed on the ground lead as using a single-pole switch would leave on the 'neutral' lead. I'm not seeing any significant danger here. What am I missing?
  
 But the whole question may be moot. In studying the Mouser catalog, I'm having trouble identifying a switch I like which is also rated at 250vDC


----------



## LV26

johnthurston said:


> I'm in North America where I'm working with single-phase 120VAC. In my polarized, grounded, NEMA-15 outlets, the ground lead is at the same potential as the 'neutral' lead. Using a double-pole switch on the mains (to disconnect both the 'hot' and the 'neutral') is going to leave exactly the same potential exposed on the ground lead as using a single-pole switch would leave on the 'neutral' lead. I'm not seeing any significant danger here. What am I missing?
> 
> But the whole question may be moot. In studying the Mouser catalog, I'm having trouble identifying a switch I like which is also rated at 250vDC


 
 Hello.
 1) Not all outlets polarized
 2) There are many outlets in Europe, Asia, Africa, etc. which Not polarized. 
	

	
	
		
		

		
		
	


	



  
 3) I think you can findout in UL and CSA standard. I haven`t direct info, but you can see Delta 06AB2D Power entry module datasheet.
 (http://www.digikey.com/product-detail/en/06AB2D/1144-1009-ND/3830632)
  
  
 -- Regards,
 Victor
  
 P.S.
 Discharging caps require only few minuts.
 How often you need to do this? And why?
 I just finish with my Bijou and never has such issue.


----------



## flatbroker

Some Bijou porn for a Monday night.

 1st Bijou build.  Regal's mod w/ 6N6P's and 6922's.  1/8" aluminum plate on Cherry chassis.  Allied 6K56VG Xformer.  Paralleled 80mfd ASC poly output caps.  Sounds good.

 2nd Build.  Paralleled 80mfd GE motor run caps.  270FX Xformer.

 Unbelievable dynamics.  
  
 Only noise on either build with HD600's or DT880's(600) starts at 4/5 volume with no NFB.  Build 2 is the best I have ever heard with HD600's.  DT880's bass is great, but they are still a little too bright for me.  Build 1 is good, but the ASC caps are a little grainy on the top end.  Yea that's a Sansa Clip Zip as the source.  It's dac is good enough to leave the USB dac in the drawer.  24/96 with rockbox.  Meier crossfeed.  No netbook.  Everything fits in the DT880 softcase.


----------



## LV26

Hello,
 Nice build. 
	

	
	
		
		

		
		
	


	



  


> Only noise on either build with HD600's or DT880's(600) starts at 4/5 volume with no NFB


 
 Uniform noise? 50/100 (60/120) Hz?
 New tubes? If yes you need 50-100 hour for "preheating".
 Try connect Volume and NFB shafts to star ground point.
 On my build noise disapear after some time (was very very low level at max volume)
 Shafts are not connected with star ground.
  
 -- Good Luck.
  
 P.S.
 I need wait for this week for finish heating my Bijou.
 Then need check PSU voltage and internals.
 Will inform ASAP.


----------



## flatbroker

No 60Hz or 120Hz hum at all, just some soft 12-14kHz hiss.  Very faint, but noticeable.
  
 I probably had 30 hours on build 1.  I stole its base and tubes for build 2.


----------



## LV26

No switching electronics near Bijou?
 LED lamps, etc.


----------



## flatbroker

No. I keep it in a quiet corner away from everything. Mobile phone, within range, messes with it though.


----------



## LV26

Flatbroker,
  
 Try connect Volume and NFB shafts to star ground point.
 This *can* help.


----------



## flatbroker

lv26 said:


> Try connect Volume and NFB shafts to star ground point.
> This *can* help.




The hiss is only audible with source paused and volume cranked way above listening level. With a little NFB it is gone. The HD600's sound better with about a 1/4 turn of NFB. Tightens the bass up and seems to exert a little control over everything else. I am completely blown away by the silence of this amp as it is.

That's a nice looking Bijou you built. What headphones are you using? I like the HD600's and HD580's with mine. DT880 is good. HD650 not so much. DT990's suck with this and every other amp I've ever tried them with, so no surprise there.


----------



## LV26

I`m curently use Grado SR80i... Yeah... not a good choice for Bijou.
 But with low impedance headphone Bijou great too...
  
 Will collect money for DT880 600 Ohm.
 and newest (not designed yet) γ3 DAC form AMB Labs.


----------



## flatbroker

Unless you've lost more of your high frequency hearing than me, you ought to consider HD600 too. 600ohm DT880 bass is better, but I get burned out on them after an hour. HD600 are good for hours. Laid back but the detail is there.


----------



## balderon

flatbroker said:


> lv26 said:
> 
> 
> > Try connect Volume and NFB shafts to star ground point.
> ...


 

 Did you isolate the source of the hiss? Do you still hear hiss if you ground the inputs to the Bijou?


----------



## flatbroker

I haven't tried to isolate or eliminate it. It's great the way it is. Noise is imperceptible at even loud listening levels. Only get subtle hiss at near max volume with no NFB. Actually, I only mentioned it as a technical observation about how quiet these amps are. I surely didn't mean to disparage this great design, but if you are telling me I can get this thing dead black at max gain, I'm listening.


----------



## Johnthurston

My Bijou has passed its smoke-test and is currently making music 
	

	
	
		
		

		
		
	


	



  
 I have it encased in a plastic toolbox. The boards are screwed to the under side of the lift-out tray. There is space to store the transformer under the tray, but I need to lift it out to kill the hum while it is playing. I'm still dreaming up the 'real' case for it. Right now, I'm leaning towards bamboo and brass.


----------



## LV26

Hello,
  
 Some Bijou builders use Motor Run Capacitors
 for output DC-blocking caps.
  
 What is a best choice for Motor Run Capacitors?
 Could you recommend some part numbers, please?
  
 -- Regards, Victor


----------



## nikongod

Most people using motor-run caps do so using surplus parts. At which point, part numbers are kind of pointless. What one guy could get 3 months ago is no longer available, but something else surely is.


----------



## flatbroker

> What is a best choice for Motor Run Capacitors?
> Could you recommend some part numbers, please?
> 
> -- Regards, Victor


 
 Look at ebay auction #251157598293.
 100 mfd, 5 for $50.  They are Temco brand.  I have no idea if they are any good, but at $10 a pop they may be worth a shot.
  
 Ebay #111355934421
 80 mfd Dayton.  These should be good to go as far as construction quality goes.  No idea how they sound. $9 each.
  
 A lot of the caps described as run caps have 3 terminals.  These are dual start/run caps and are not what you need.


----------



## LV26

flatbroker said:


> Look at ebay auction #251157598293.
> 100 mfd, 5 for $50.  They are Temco brand.  I have no idea if they are any good, but at $10 a pop they may be worth a shot.
> 
> Ebay #111355934421
> ...


 

 Thanks
 1st lot 65$ for delivery
 2nd not available for delivery to my country.
  
 Oil caps are not critical for me.
 Also I can try to find them near my location.
  
 -- Regards,
 Victor


----------



## 00940

New motor run caps are difficult to find in values above 40uF (they exist but aren't stocked by major suppliers). The arcotronics/kemet C274AC35400AA0J is probably the most widely available.
  
 In Europe, the audyn mkp-qs are probably your best bet for high value mkp caps.


----------



## LV26

Thank you.
 I think Audyn a good choice (and available)
 I think WIMA MKP10 available with 47 uF/400VDC... Need check stock.
  
 BTW
 What is a difference between Audyn QS and Q4 and Q6?
 I compare tech. spec. I think they all provide very close parameters (DF, for example)


----------



## 00940

lv26 said:


> Thank you.
> I think Audyn a good choice (and available)
> I think WIMA MKP10 available with 47 uF/400VDC... Need check stock.
> 
> ...


 
  
 From the datasheet, the wima mkp10 stops at 22uF for 400Vdc.
  
 I've no experience about audyn qs vs q4/q6. I've used some mkp-qs in the past, they seemed ok to me. There are some discussions on French forums, mostly about caps in speakers crossovers... some say that the qs are a bit better than the q4, some say that they sound the same. Many say that the ones rated for higher voltage sound better; it could thus be interesting to compare the qs vs the q6 (the 100uF exists in Q6 but not in qs-630).
  
 As far as I'm concerned, pretty much any mkp will do for output coupling. It's not a position where specs are critical.


----------



## LV26

00940,
 Thank you for the answer.
 I decide to roll caps not now...
 First I need change my headphones to high impedance (DT880 600 Ohm I think)
 No chance to get more performance with Bijou and Grado SR80i.
  
 -- With best Wishes,
 Victor
  
 P.S.
 For info:
 Bijou output capacitor (C5) rated for 250V.
 WIMA MKP 10 series have a 33 uF/250V caps.
 But I really like Audyn for highest available capacitance.


----------



## 00940

lv26 said:


> First I need change my headphones to high impedance (DT880 600 Ohm I think)
> No chance to get more performance with Bijou and Grado SR80i.
> ... For info: Bijou output capacitor (C5) rated for 250V.


 
   
That seems reasonable ; it is already a very nice amp you have there. Better spend money on better headphones.

  
 Yes, I know for the bijou.... I'm a bit paranoid however and prefer to use output caps rated for the full unregulated voltage.


----------



## LV26

Just find very interesting parts
 http://www.digikey.com/product-detail/en/C4ATDBW5600A30J/399-6223-ND/2783185
 http://www.digikey.com/product-detail/en/C4ATFBW5400A3NJ/399-5949-ND/2704603
  
 Probably will be usefull for you. Look at datasheet (VERY low ESR and DF)
  
 + "100 USD" Champion 
 http://www.digikey.com/product-detail/en/C44AFGR6200ZE0J/399-6265-ND/2783746


----------



## Johnthurston

Detaching the mosfets (Q1 and Q2) from the power supply board will let me relocate them in my case and provide better heat sinking. There are significant voltages present on the legs, but if they are adequately insulated, should I expect any bad behavior by adding 3" of pig-tail to them?


----------



## yiancar

You should not really be worried abt the mosfet being cooled. I have mine on the original position next to the tubes in an enclosure with little airflow and well they work fine. Stability is more abt "constant" heat than being cool ( assuming ur in the working temp range).
  
 Any way, no if u use insulated wire ull not run into any problems. However if you really are looking into lowering the temps I would advice ditching the heat source (aka tube) and replacing it with 2 high voltage.


----------



## hrolfur

Hi, I just finished putting my Bijou together last Saturday evening and was able to listen to it and everything sounded just fine, the PS was giving out steady 250V. Then The day after I plug it in when I get home from work and just let it sit there for around 2 hours, when I get back to it I decide to measure the output of the PS again. This time it shows 276V and then the R4 resistor on the board burst into flames. I replaced it with a new one this morning and readjusted the trimpot to lower the Voltage, the R4 blew up again as soon as I put power on the board. I don’t even have time to check the Voltage before it blows. So now I’m thinking something else must be wrong.
 I bought this from glassjaraudio.com, and I’m using Hammond 370DAX.
 Does anyone have any idea what I’m doing wrong here?


----------



## yiancar

hrolfur said:


> Hi, I just finished putting my Bijou together last Saturday evening and was able to listen to it and everything sounded just fine, the PS was giving out steady 250V. Then The day after I plug it in when I get home from work and just let it sit there for around 2 hours, when I get back to it I decide to measure the output of the PS again. This time it shows 276V and then the R4 resistor on the board burst into flames. I replaced it with a new one this morning and readjusted the trimpot to lower the Voltage, the R4 blew up again as soon as I put power on the board. I don’t even have time to check the Voltage before it blows. So now I’m thinking something else must be wrong.
> I bought this from glassjaraudio.com, and I’m using Hammond 370DAX.
> Does anyone have any idea what I’m doing wrong here?



 
 can u put tome quality pics of both the back and the front of the psu boards?


----------



## hrolfur

Sorry I can't upload picture strait to this page with my account (it's new). 
 Here is a Imgur link http://imgur.com/a/S7Uph
  
 Thanks.


----------



## yiancar

hrolfur said:


> Sorry I can't upload picture strait to this page with my account (it's new).
> Here is a Imgur link http://imgur.com/a/S7Uph
> 
> Thanks.


 

 only thing i cn suspect is faulty mosfets , however just to be sure can you also mesure the ac output voltage of the transformer as well as dc voltage between tube pin 3 and ground. just have ur meter ready, turn on get a mesurement turn off. dont replace the burned resistor, it doesnt matter for this test


----------



## ady1989

Maybe someone here can help me. I've been searching around online and I have been unable to find out the power output of the Bijou. Does anyone know what it measures? I think it's unable to drive the HE500's to very high volume due to bad bass distortion when the volume pot is at around 60% and no negative feedback. It could also be the headphones and their limitation. Anyone have experience with HE500's and their Bijou amp?


----------



## LV26

Hello, all
  
 Any activity with Bijou? Or summer time...
 My Bijou finally "pre-burned".
 I`m waiting for DT800 600 Ohm. Will compare with Grado 32 Ohm.
  
 Good Luck to all
 -- WBR, Victor


----------



## yiancar

lv26 said:


> Hello, all
> 
> Any activity with Bijou? Or summer time...
> My Bijou finally "pre-burned".
> ...


 

 meaning construction or improvement ?


----------



## LV26

yiancar said:


> meaning construction or improvement ?


 

 I mean sound improvement with DT880. 
 At least I would be surprised if Grado SR80i better then Beyerdinamic DT 880 (600 Ohm) with Bijou.


----------



## yiancar

lv26 said:


> I mean sound improvement with DT880.
> At least I would be surprised if Grado SR80i better then Beyerdinamic DT 880 (600 Ohm) with Bijou.


 

 I assume u removed nfb?


----------



## LV26

No yet.
 I haven`t DT880 at this moment
 I`m waiting for delivery.
  
 You wrote about totally removed NFB (and NFB potentiometer too) or using minimum NFB with DT 880.
 Are any sound difference really BIG?
 No NFB vs Minimum NFB


----------



## yiancar

lv26 said:


> No yet.
> I haven`t DT880 at this moment
> I`m waiting for delivery.
> 
> ...


 

 there is some, just an "extra" bit, you should try it out, u can leave it on minimum on one channel and remove it completely on the other.
  
 have u rolled any tubes?


----------



## LV26

> have u rolled any tubes?


 
 Yes
 I use Tungsram E88CC (red label, mil/industrial, 1965, 1968 years) and USSR 6N6P (1978 year)
 Regal mod (for 6922/6DJ8) applied.
  
 Also I modify heater wiring (like "star" topology) with each tube heater wires shielded. All heater shields connected with main star ground bolt.


----------



## yiancar

lv26 said:


> Yes
> I use Tungsram E88CC (red label, mil/industrial, 1965, 1968 years) and USSR 6N6P (1978 year)
> Regal mod (for 6922/6DJ8) applied.
> 
> Also I modify heater wiring (like "star" topology) with each tube heater wires shielded. All heater shields connected with main star ground bolt.


 
 I use 6H30 which i find to be more dominant(powerful) than the 6DJ8.
 Can we have a picture of or heater shielding?


----------



## LV26

Yes
 Lot of photos
 http://postimg.org/gallery/4b4au5w6/
  
 especcially
 http://postimg.org/image/cwjob0ggl/
 huge white DIY cables (twisted wires + shield + fiber tube)


----------



## AudioCats

(I know it is probably somewhere in this giant thread, but somehow I can not find it.......)
  
 which  electrolytic caps are good for using as output caps? Is there a particular brand/model that is noticeably better than the others?


----------



## nailbunny7

I used standard audio nichicon snap in caps (~$4 each). Or, if you have a large budget, you could use Black Gate 150uf 350V ones (they have them on sale at Parts Connexion for 60 each, down from 180 each) which are good if you don't intend to use anything lower than 250 ohm impedance (lower than that, and you might experience a bit of bass cut off, I think). I personally use 100 uf Obbligato Film and Oil caps, whitch are good for my 600 ohm Beyers.


audiocats said:


> (I know it is probably somewhere in this giant thread, but somehow I can not find it.......)
> 
> which  electrolytic caps are good for using as output caps? Is there a particular brand/model that is noticeably better than the others?


----------



## bhjazz

Hey AudioCats!  Been a long time!
  
 To find the discussions in this thread for the output caps, just search for C5.  Certainly lots of options.
 The stock one, for reference, is the 470u with a 1u bypass (C6).


----------



## ericj

audiocats said:


> (I know it is probably somewhere in this giant thread, but somehow I can not find it.......)
> 
> which  electrolytic caps are good for using as output caps? Is there a particular brand/model that is noticeably better than the others?


 
  
 There was a big deal about photo-flash caps but IMHO some of that was based on the idea that they are somehow magical pixie dust because they were revolutionary 40 years ago. but today they are just slightly more robust than good switching power supply caps. 
  
 I am using CDE LX380 470uf bypassed by a 1uf wima. I like it, but I'm weird.


----------



## ericj

ady1989 said:


> Maybe someone here can help me. I've been searching around online and I have been unable to find out the power output of the Bijou. Does anyone know what it measures? I think it's unable to drive the HE500's to very high volume due to bad bass distortion when the volume pot is at around 60% and no negative feedback. It could also be the headphones and their limitation. Anyone have experience with HE500's and their Bijou amp?


 
  
 huh, that was months ago, but, the maximum power output of both halves of a 6n6p is about 8 watts. 
  
 the bijou is probably not pushing that much since it is an OTL design for headphones but you'd have to ask Alex.


----------



## 00940

The output stage iddles at 20ma. That means the max current (peak) is 40ma at best. Into a 38r load, peak power is thus 38*0.04*0.04= 60mW peak, about 30mWrms.
  
 Into the HE500, with its 89db/mW rating, it means you can at best get up to roughly 104dB before distortion gets crazy. But without feedback, distortion will already be quite high at that point. With feedback, it could be a bit better.


----------



## AudioCats

bhjazz said:


> Hey AudioCats!  Been a long time!
> 
> To find the discussions in this thread for the output caps, just search for C5.  Certainly lots of options.
> The stock one, for reference, is the 470u with a 1u bypass (C6).


 
  
 Thanks!
  
 I will search C5 see what has been said and done.


----------



## Gustave G

I just completed the power supply and on of the channels.
 The output tube, V2,  on my board are idles at *30ma*, and V1 at 10ma (I changed the resistors to run each side of V1 at 5ma).
 The 6n6p with a bios voltage at 2.3v @125v plate voltage = 30 ma.
  
 R3 = 30k
 R3 = 487
 R5-7 = 10.2k (Regal's mod shows 10k. but if you do the math, it should be 10.2k).


----------



## Gustave G

Since you did the Regal's mod, you might want to change R7 & R8 in the power supply.
 The Mod increases the idle current from 32ma to 40ma per channel ( @250V ).
  
 Depending on which power transformer, you want to decrease them to keep at least 30V across Q2.
 I used the R80-36 R-core, so I changed R7 & R8 to two 75R 3W in series (150R).
 -Putting 2-75R together fits very nicely into the PBC-
  
 Also note that if you us the Hammond 270DAX, its plate resistance is too low (177R Plate to Plate, 88R5 from center tap) for the EZ81,
 You should add a plate resistor to match the specs of the EZ81.


----------



## orson56

*BIJOU ON STEROIDS*
  
 I have already built two Bijou in past years, a really good headphone amplifier; the first was an original version with all components as shown in the schematic, the second in the first time I had recalculated with Multisim and Spice models to use russian 6N1P-EV and 6N6B-I with no NFB and was already a bit better than the original.
  
 This year I wanted to go one step further and design a pumped Bijou! Since I have many russian tubes 6N23P and 6S19P  I wanted to redesign it to use these great tubes. After a few weeks of study and trials with Spice models and Multisim I built this new version of Bijou: *Bijou on Steroids*.

 The scheme remained the original, only the values ​​of the components are obviously changed, I have used resistors in place of the diodes, no NFB. Even the power supply is changed, I went back to a classic diodes and RC filters.

 The first time I turned it on I was very impressed: no noise, no hiss and no buzz. And the sound... WOOOW !!!!! really spectacular with my headphones (Beyerdynamic DT 990 Pro and the Sennheiser HD590).
 This is confirmation that the Alex Cavalli Bijou circuit is really a great project where there is room to do even mods.
  I have built and designed many headphone amps: transistors, hybrids, tubes but this is the best headphone amplifier that I made.


----------



## FallenAngel

What do you guys think of C5/C6 being replaced by 2x 100uF giant oil caps in series?


----------



## ericj

fallenangel said:


> What do you guys think of C5/C6 being replaced by 2x 100uF giant oil caps in series?


 
  
 The maximum 1st capacitor size after the rectifier tube is 50uf. So if you mean two 100uf in series, resulting in an effective capacitance of 50uf, that should work.


----------



## FallenAngel

ericj said:


> The maximum 1st capacitor size after the rectifier tube is 50uf. So if you mean two 100uf in series, resulting in an effective capacitance of 50uf, that should work.




I was talking about the amplifier board, output caps. I also meant in parallel.


----------



## ericj

Sure. Go nuts.


----------



## FallenAngel

Still trying to figure out the layout.


----------



## FallenAngel

Hey tube amp guys,

Layout design help please if you could spare the time.


----------



## Johnthurston

Is this going to be a fully enclosed chassis? That is, front-mounted controls with everything inside the case and nothing protruding? If so, those caps are going to make it pretty tall, aren't they?


----------



## FallenAngel

johnthurston said:


> Is this going to be a fully enclosed chassis? That is, front-mounted controls with everything inside the case and nothing protruding? If so, those caps are going to make it pretty tall, aren't they?


 
  
 Yep, fully enclosed. The chassis is 6" tall.
  
 I'm kind of sticking to the layout in the photo.


----------



## FallenAngel

Wiring layout. What do you guys think?


----------



## FallenAngel

Just a quick and simple question : 6N6P-i or 6N6P?
  
 Looks like 6N6P is fine.


----------



## FallenAngel

Another question : C5/C6 - can I drop it down to 200V?
  
 Looks like it's possible, but highly not recommended.


----------



## FallenAngel

Bizarre initial setup...
  
 Left channel LED is on, but the sound is nothing but buzz.
 Right channel LED is off, but the sound is good.
  
 I'm looking into what's going on. Change of 6N6P tubes does nothing.
  
 3 tequila drinks at lunch isn't helping my concentration and I can't see anything wrong with the board...


----------



## FallenAngel

"Progress" - one step forward one step back.
  
 I had a solder joint between R1 and pins 6 and 7 on V1 (6922 tube) by a little solder splatter when I was doing the wiring in the chassis. No more LED light issues, heaters all work - around 6.9VAC.
  
 The amp plays music and sounds "OK, I guess", but here's the issue. The PSU is set to 250VDC output without the amp boards connected. When I plug in the amp boards though, it drops down to around 130V.
  
 With such a huge drop in B+, it's not realistic to check the voltage points on the amp board because it would all be skewed.
  
 I'll look around closer today and update. Any initial thoughts would be appreciated though.
  
 I'm using EZ81 rectifier, 6922 input and 6N6P output tubes.
  
 Thanks!


----------



## FallenAngel

It looks like it takes a few seconds to stabilize at 250V on the PSU. It holds voltage consistently.

Once I connect either board, B+ drops to 140-150v and with both amp boards connected it shows 115v.

Resistor values on both boards should be correct. Before I start checking every component by hand separately, sent ideas?

Thanks

UPDATE : After many hours of reading through about half of this entire thread, I've answered a lot of my questions (as above).

Next up is to check if I fried my MOSFETs with a 100KOhm test load and confirm that they can just be replaced.

One thing I'm still not clear on is what characteristics of a MOSFET I should look for when selecting one for this application. After pouring through datasheets of the two recommended ones, I don't see why I can't just throw an IRF820 in there instead of the IRF820B.


----------



## FallenAngel

Update:
  
 Tested the PSU with a 100K load resistor and after a bit of back and forth for about 30 seconds, it stabilized at 250V. Still the same issue exists when connecting the amp boards.
  
 I'll try to replace the IRF820B with some IRF840 tomorrow and see what happens, but other than that, I'm out of ideas.


----------



## FallenAngel

Just as I thought thanks to the copious amounts of knowledge in this thread, blown IRF820. Replaced with IRF840 and she sings like an angel.


----------



## dBel84

Home sick today and browsing all sorts of fun things - glad to hear you got this sorted. Looks like an impressive iteration of an old favourite..dB


----------



## FallenAngel

Yeah, it was a very fun build. A few issues, but there's lots of knowledge in this tread. Too bad it's not too active anymore.
  
 I had it at my meet this weekend and it really was the HD800 killer. Lots of wonderful syrupy tube fun.


----------



## dBel84

good to hear . Post a pic of the completed amp. I didn't check but did you include all the mods too?
  
 ..dB


----------



## FallenAngel

It's actually listed for sale with pics there. Selling for parts costs of course. 
 http://www.head-fi.org/t/796973/fs-high-end-pure-tube-amp-bijou


----------



## yaboin

Cavalli's website has been updated and most of the images for the bijou will not display anymore.
  
 Does anyone have the schematic for amphead's mod?  And the drill templates would be nice also...  
  
 thank you!


----------



## bluemonkeyflyer

yaboin said:


> Cavalli's website has been updated and most of the images for the bijou will not display anymore.
> 
> Does anyone have the schematic for amphead's mod?  And the drill templates would be nice also...
> 
> thank you!


 
  
 I second that.
  
 I have a kit from glassjar/Jeff ready to go. I can determine most of the caps but not the resistors. I've searched this thread and with Google but no joy.
  
 If anyone has the v2.0 BOMs for the amp boards and PSU board, parts designations, and schematics, I will be grateful and in your debt.
  
 ~ BMF


----------



## bluemonkeyflyer

Google waybackmachine. 
Type cavallaudio.com into search window. 
Try various dates between 2007 and Feb 2016. Most of the information is there but I cannot find a saved page for PSU schematic and a few others. Better than nothing.


----------



## dBel84

I have alerted Alex to this problem. He is at CanJam so it may take a little longer to get fixed.

Now would be a good time to dream up the amazing chassis to house the amp in 
..dB


----------



## bluemonkeyflyer

dbel84 said:


> I have alerted Alex to this problem. He is at CanJam so it may take a little longer to get fixed.
> 
> Now would be a good time to dream up the amazing chassis to house the amp in
> 
> ...


 
  
 Thanks dB, and thanks to Alex. 
  
 Hmm, maybe a Bijou UFO Double Decker.


----------



## yaboin

Yep, thanks!
 Thinking Padauk wood and green tinted glass


----------



## bluemonkeyflyer

Bijou sounds fantastic!
  
 Major kudos and many thanks to dBel84 for guidance on this and other projects...EHHA Rev A, CK2III, and more...and to Dr. Alex for the DIY designs, all of which sound great!!
  
 ~ BMF
  
 PS: thanks to Jeff at glassjaraudio for the excellent kits that makes DIY easier and more fun.


----------



## pepe8086

pabbi1 said:


> Balanced it does...
> 
> 
> Quote:
> ...


 
@pabbi1 i know it's been a while since someone got the idea of hooking Bijou to speakers, can you or anyone share the word here - is it really worth the effort of doubling the Bijou circuitry just to run the speakers?
  
 I have full range Audio Nirvana AN10, inside EZ-10 back-loaded horns enclosure. So far I was running them from my old restored sansui au-4900, and after todays trial (speakers connected via tiny cellphone-handsfree-cable) they sounded wider and deeper when fed from Bijou, but with higher volume the bass got distorted, I wonder whether this was due to high wire resistance, poor connection or i've simply hit amp limits.
  
 So basically i'm deciding whether i'm starting new project or upgrading Bijou. But I like the idea of OTL
 If upgrading - I should protect speakers with relay, right?
 Do I need to change feedback, somehow?
 What output power Bijou provides per channel?
  
 As this is probably my first post here - I'd like to say *THANK YOU* to all of you who share it's knowledge - thanks to that I was able to stay unnoticed for years


----------



## giraz

Hi to all.
 It's about a month I'm looking around to build a DIY tube amp for headphones, and I'm studing about Cavalli Audio Bijou amp.
 I'm trying to recover all images and files from the Cavalli Audio website, using Wayback Machine, but seems that something is unrecoverable.
 I'm also trying to read the most part of the 280 pages of the thread..
  
 I'd like to know, in the occasion I really start to build this project, if there is still some user in the thread that can follow me in the occasion I have some problem to troubleshot. In particular, living in Italy, I would interested in some one that can help me on finding european articles (for example 220V power transformer, capacitors, ecc.).
 In addition, I'd like to know if there is some sort of brief along the thread,  with the last and known precautions, tweak and optimisations for this amp (being that the original project goes back to 2007)
  
 Moreover, I would like to know if this amp would well fit my planar magnetic Audeze Sine with 20 ohms impedence.
 Here the full datasheet:
  

StyleOn-ear, closed-backTransducer typePlanar magneticMagnetic structureSingle-sided FluxorMagnet typeNeodymiumDiaphragm typeUniforceTransducer size80 x 70mmMaximum power handling6WMaximum SPL>120dBFrequency response10Hz – 50kHzTotal harmonic distortion<1% full spectrum @ 100dBImpedance20 ohmsOptimal power requirement500mW – 1WWeight230g
  
 Thank you in adance, bye!


----------



## pepe8086

@giraz Despite fact I'm from EU, the best option for me was to order from http://glassjaraudio.com/product.sc?productId=12&categoryId=6, it ships from US. I've got all the parts, which are picked in great quality/price ratio. I believe this is Jeff's side hobby to run such an eshop, so be prepared he is not super responsive, all the time (i've got his response within 1-2days - which is excellent). But patience might save you a lot by getting all the circuitry parts at once.
  
 Then go over mods and pick one you intend to apply, this might need some more additional parts.
  
 For transformer, there is multiple options how to source Hammond in EU(at least mouser). For me the shipping costs for hammond covered expenses for custom made transformer by local manufacturer. 
  
 Also I remember there was an option to use ~240VAC directly from power cord, so there was need get just transformer for heaters (6.3V)
  
 I'm not that experienced to tell you for sure how exactly Bijou will handle 20Zohm Audeze.


----------



## giraz

Thank you @pepe8086 for the extensive reply. I contacted Glass Jar Audio and I'm waiting for an evaluation about shipping costs.
 For transofmers, I will search about toroidal transformes too..
  
 Thank you for now, any other reply would be very appreciated.


----------



## funch

The Bijou does not have the current output to properly drive the Audeze's. I tried an LCD-2 with a Bijou I used to have, and although it produced sound, it didn't really do the  job.


----------



## bluemonkeyflyer

I deleted my post because Cavalliaudio dot com > Projects > Bijou has detailed build information.


----------



## giraz

Quote:
  


funch said:


> The Bijou does not have the current output to properly drive the Audeze's. I tried an LCD-2 with a Bijou I used to have, and although it produced sound, it didn't really do the  job.


 
 Are you sure this would be the case with Sine too? Comparing specs I see Sine needs less current than LCD-2 to be properly powered and also impedence of LCD-2 is 3x and more than Sine:
  
*LCD-2*

StyleOpen circumauralTransducer typePlanar magneticMagnetic structureProprietary push-pull designMagnet typeNeodymiumTransducer size106 mmMaximum power handling15W (for 200ms)Sound pressure level>130dB with 15WFrequency response5Hz – 20kHz extended out to 50kHzTotal harmonic distortion<1% through entire frequency rangeImpedance*70 ohms*Efficiency101dB / 1mWOptimal power requirement*1 – 4W*
  
  
*Sine*

StyleOn-ear, closed-backTransducer typePlanar magneticMagnetic structureSingle-sided FluxorMagnet typeNeodymiumDiaphragm typeUniforceTransducer size80 x 70mmMaximum power handling6WMaximum SPL>120dBFrequency response10Hz – 50kHzTotal harmonic distortion<1% full spectrum @ 100dBImpedance*20 ohms*Optimal power requirement*500mW – 1W*Weight230g
  
  
  


bluemonkeyflyer said:


> I deleted my post because Cavalliaudio dot com > Projects > Bijou has detailed build information.


 
 Thank you, but Cavalli Audio web site has a problem at the moment, and almost all links to image are broken, so your post was really useful. I contacted Cavalli Audio and they said that they would fix the problem, but in the mean time your post was very useful I think.


----------



## bluemonkeyflyer

giraz said:


> Are you sure this would be the case with Sine too? Comparing specs I see Sine needs less current than LCD-2 to be properly powered and also impedence of LCD-2 is 3x and more than Sine:
> 
> *LCD-2*
> 
> ...


 
 OK. I'm glad you were able to retrieve the copy/paste files before I deleted them. I did not try the Cavalli files to see if they would open. I saw them listed on Alex's website and assumed they were active...and then deleted my post.
  
 Let me know if you need anything else.


----------



## bhjazz

fallenangel said:


> Yeah, it was a very fun build. A few issues, but there's lots of knowledge in this thread. Too bad it's not too active anymore.


 
  
 I totally agree.  And oddly enough, I never completed my own Bijou build, which is why I am back!  I'm going back through my parts boxes and such and trying to determine just what I still need to get this one going.  So a few questions:
  
 1) For V2, we have the option of 6N6P (as included in the kit) or ECC99.  I know these have different heater configs.  6N6P tubes seem to be mostly available through ebay.  Is it worth it to stick with those, or should I build with the ECC99 in mind?
  
 2) Regal Mods: yes or no?!  (I do know I would need the ECC99 for Regal mods)
  
 3) C1/C3/C4 confusion: I see that the original versions of C3 and C4 are 100uf/400V.  I have also read that increasing these to 220uf/400V (and C1 to 22uf) would lower the bass cutoff.  Does this change the NFB, and would it narrow the range of usable headphones (say, if I had a pair of HD600 and a pair of PS500e)?  That one confuses me a bit.  
  
 4) EDIT: On the heels of question 3, I still have some pabbi Rubycons (410uf/300V).  Is there a calculation to get this working correctly if I make changes to C3/C4?  What if I want to use a 120uf?
  
  
 Thanks for any assistance!
  
 Brian


----------



## FallenAngel

bhjazz said:


> I totally agree.  And oddly enough, I never completed my own Bijou build, which is why I am back!  I'm going back through my parts boxes and such and trying to determine just what I still need to get this one going.  So a few questions:
> 
> 1) For V2, we have the option of 6N6P (as included in the kit) or ECC99.  I know these have different heater configs.  6N6P tubes seem to be mostly available through ebay.  Is it worth it to stick with those, or should I build with the ECC99 in mind?
> 
> ...


 
  
 1) I used 6N6P as they are inexpensive and very good. I have 4 extras, so just PM me if you want a pair for like $20. I figure that's a decent price with shipping (without the month long wait from eastern Europe).
 2) I didn't, so I can't comment.
 3) C1 - I used an oil cap but later learned that it really doesn't matter much. Just use anything "decent" quality as it's for the feedback loop. C3/4 - these are 100nF (not uF - they're 0.1uF) and should be as good of a cap as you can find. These are signal path caps between the stages.
 4) Read #3.
 I think you're thinking of C5 instead, which is a large cap (specified 470uF). I actually used a pair of 100uF oil caps in parallel, making it 200uF total instead, but I had the space for it and these are BIG (soda can size each). Easy way to make your build hundreds of dollars more expensive. You can go with a "good" electrolytic cap at like $10, or go for some film or oil caps at $200.


----------



## bhjazz

fallenangel said:


> 1) I used 6N6P as they are inexpensive and very good. I have 4 extras, so just PM me if you want a pair for like $20. I figure that's a decent price with shipping (without the month long wait from eastern Europe).
> 2) I didn't, so I can't comment.
> 3) C1 - I used an oil cap but later learned that it really doesn't matter much. Just use anything "decent" quality as it's for the feedback loop. C3/4 - these are 100nF (not uF - they're 0.1uF) and should be as good of a cap as you can find. These are signal path caps between the stages.
> 4) Read #3.
> I think you're thinking of C5 instead, which is a large cap (specified 470uF). I actually used a pair of 100uF oil caps in parallel, making it 200uF total instead, but I had the space for it and these are BIG (soda can size each). Easy way to make your build hundreds of dollars more expensive. You can go with a "good" electrolytic cap at like $10, or go for some film or oil caps at $200.


 
  
 1) Thanks for the offer.  That definitely sounds like a decent price.
  
  
 3) Thanks for the clarification on uf vs nf.  Yow!  I would have conjured the magic smoke for sure.  
  
 4) Yes, you are correct: I mean C5.  Is there any relation between the value of C5 and the values of C3/C4?  In the discussions, I am not seeing that there is.
  
 Thanks!  Much appreciated.


----------



## FallenAngel

bhjazz said:


> 1) Thanks for the offer.  That definitely sounds like a decent price.
> 
> 
> 3) Thanks for the clarification on uf vs nf.  Yow!  I would have conjured the magic smoke for sure.
> ...




1) I figure that's what I paid so I'll pass it on if you want.
3) No smoke, but they'll be oversized.
4) Not that I know of. Input of second stage allows for such a small C3 cap so I don't know if a reason to go higher. I'm sure it wouldn't hurt but it's not necessary. As for C5, you can go up to 1000uF but quality is more important than quantity, just match it to your headphones. 200uF is enough for 300 ohm headphones, 470uF is good for 120, and you might want higher for 32/50 ohms


----------



## bhjazz

Excellent.  Thanks for the tips, I appreciate it.  I'm off to shop!


----------



## bhjazz

In reference to the Regal mods, the Cavalli site reads:
 "...Regal's mods requires using ECC99s (not 6N6Ps) and the EZ81 Power Supply."
  
 However, in this thread there seem to be plenty of folks who have the Regal mods using a 6N6P.  
  
 I have the EZ81, so am I good for using the Regal mods with a 6N6P?
  
 ALSO! Does anybody know what Glass Jar Jeff originally sent out with the kits?  The tubes are marked 6N6П, which, depending on the site you read, can mean either 6N6P or 6N6Pi.  
	

	
	
		
		

		
			




  
 Thanks as always!


----------



## ericj

bhjazz said:


> In reference to the Regal mods, the Cavalli site reads:
> "...Regal's mods requires using ECC99s (not 6N6Ps) and the EZ81 Power Supply."
> 
> However, in this thread there seem to be plenty of folks who have the Regal mods using a 6N6P.
> ...


 
  
 The site is a little confusing. What it means by that is that Regal's values are correct for the ECC99 but not for other tubes.
  
 When i was digging around six months or so back i found resistor values to increase the plate current on 6n6p tubes. And 6n1p - which is the combo i am using. I don't think i implemented it yet, and i am not sure where i found those values, but I will look again because i am revamping my beloved old ToasterAmp(tm) Bijou lately. 
  
 Listening to it right now actually, with a pair of modded yamaha YH-1.
  
 I'm working on a board design for a c1237 based output protection module for it (and other OTL tube amps) that will run off the heater supply. Turn-on delay and DC protection, and disconnects the output immediately when AC power is cut. No idea when it will be complete but I'll mention it in this thread when it is. 
  
 As for the kits i suggest you contact Jeff Rossel directly. I believe i have his personal email address here somewhere if you are unable to reach him through the Glass Jar website. I didn't buy a kit - probably should have. His kits were absolutely cheaper than buying parts separately.


----------



## ericj

Wait, now i see what you mean. It does say that you should do it only with the ECC99. 
  
 I don't understand why that is. Could be due to the lower plate resistance on the 6n6p. 
  
 I vaguely recall Alex telling me to make some tweaks in my 6n1p/6n6p build. But that was a long time ago, and I don't even remember if that was here, at headwize, or in email.


----------



## ericj

It's about the available power supply current. The 6n6p draws more current from B+ than the ECC99 does. 
  
 http://www.head-fi.org/t/277541/bijou-all-tube-futterman-headphone-amplifier/3855#post_7407744
  
 If you search this thread, a lot of people have done it anyway. Keep an eye on your B+.


----------



## bhjazz

ericj said:


> It's about the available power supply current. The 6n6p draws more current from B+ than the ECC99 does.
> 
> http://www.head-fi.org/t/277541/bijou-all-tube-futterman-headphone-amplifier/3855#post_7407744
> 
> If you search this thread, a lot of people have done it anyway. Keep an eye on your B+.


 
 Cool!  Thanks!  And thanks for your insights above, as well.


----------



## ericj

bhjazz said:


> Cool!  Thanks!  And thanks for your insights above, as well.


 
  
 You do need the EZ81 rectifier. You want to make sure there's enough voltage drop across the regulator in the power supply. I'm unsure of the test points off the top of my head. I need to look into it too - not sure how many volts I'm losing across the choke here.


----------



## bhjazz

ericj said:


> It's about the available power supply current. The 6n6p draws more current from B+ than the ECC99 does.


 
  
 That's good to know, then.  I still need to get a hold of Jeff Rossel and see what tubes I actually have.  The wiring differences are my final concern for this issue.  I'm wishing there were an easier way to tell (which tubes I actually have). 
  


ericj said:


> You do need the EZ81 rectifier. You want to make sure there's enough voltage drop across the regulator in the power supply. I'm unsure of the test points off the top of my head. I need to look into it too - not sure how many volts I'm losing across the choke here.


 
 Yes, I have an EZ81, as well as the 370DAX, so I should be good to go for a power supply.


----------



## ericj

bhjazz said:


> That's good to know, then.  I still need to get a hold of Jeff Rossel and see what tubes I actually have.  The wiring differences are my final concern for this issue.  I'm wishing there were an easier way to tell (which tubes I actually have).
> 
> Yes, I have an EZ81, as well as the 370DAX, so I should be good to go for a power supply.


 
  
 You should be fine on the power supply front. 
  
 The ECC99 is a modern tube from JJ. It would have a big red JJ logo on it. It's based on the 6n6p, but has higher plate resistance. 
  
 If there's no JJ logo, it's probably 6n6p-i or 6n6p-ev, and the only difference there is the heater current iirc. My heater supply is doing just fine with a pair of 6n6p-i at almost an amp each and a pair of 6n1p at 600ma each along with the EZ81. 
  
 6h30-pi was a premium option and i doubt glassjar ever sold any. You would have noticed at $30/tube. 
  
 Your preamp tubes should be clearly marked too, but i don't recall any wiring differences between 6dj8, 6922, 6n1p, or 6n23p -- the 6n23p being the real 6922 clone from russia. CEI even sold them labeled as 6DJ8. The 6n1p just has slightly lower gm and a much hotter filament.


----------



## bhjazz

Thanks for all the help, Eric. I do appreciate it!
  
 First, the input tubes are JAN Philips 6922.  I have another pair of EH 6922s (matched), and another matched pair of JAN Philips 6DJ8.  
  
 AND - I just heard back from Jeff Rossel.  Looks like the variant I have is what I suspected: Russian 6N6P.  They are marked with partial Cyrillic characters, and one is labeled CCCP.  Gotta love that.  From what I have read, these do not really need to be a matched pair.  
  
 Anyway, now I know for sure that the wiring will be using pins 4, 5 and 9 for the heater arrangement. This also means I can use the ECC99 tube as well.  Cool!  I'll have to get a pair of ECC99 for fun.
  
 The rectifier tube I have, is definitely a JJ - red logo and all.


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## bhjazz

Edit: Just noticed my Glass Jar kit includes R6 and R9 at 332k, instead of the specified at 348k.  Does this lower resistance help address the issues with using 6N6P tubes and it's affect on the B+ (as noted in this thread)?
  
 Thanks!
  
 Another Edit:  I am assuming it is related to this:
  


ericj said:


> When i was digging around six months or so back i found resistor values to increase the plate current on 6n6p tubes. And 6n1p - which is the combo i am using. I don't think i implemented it yet, and i am not sure where i found those values, but I will look again because i am revamping my beloved old ToasterAmp(tm) Bijou lately.


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## bhjazz

The Mundorf Silver In Oil caps arrived today for C3 and C4 on the amplifier boards.  Also, a pair of Mundorf MLytic AG caps for the output on my Ventus, which I hope to rebuild once the Bijou is done.  
  
 Per my previous message I sent a quick email to Jeff, and he confirmed that he does, in fact, have different values than the original BOM.  So the slight change is expected.  I also noticed that he sent 450V 680uF caps for the power supply, too.  Excellent.
  
 Things are coming together.


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## bhjazz

Edit: Never mind.  I found what I was looking for in these 283 pages...! RE: power supply and available current using Regal mods.


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## tori81

Hi,

I have found Bijou a few months ago. I have found the building instructions on cavalliaudio.com. Unfortunately the site has been closed meanwhile, and the instructions were removed. I managed to get the texts from web archives, but I couldn't get the schemantics.
Can someone send me the schemantics, tweaks, anything that can help me build the amp?

Thank you!


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## funch

You might check with Jeff here:http://www.glassjaraudio.com/   He sells Bijou kits and may be able to provide the doc's.


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## Jrossel

check here for Bijou schematics:

https://web.archive.org/web/2015110...audio.com:80/diy/bijou/main.php?page=overview


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## tori81

Thank you! I have managed to download most of the schematics.


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## bhjazz

Getting all the items out of the archive is pretty difficult.  I actually had to hit several site captures to get everything.  
In the mean time, here are a few more for you. 

Regal mods
Schematic 
Parts List

Good luck tori81!


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## ndndjsiew

Hi everybody,

Looks like we have quite a few electronic gurus here on this forum. I didn't have serious contact with electronic theory/design for about 30 years, therefore I have some problems regarding Bijou design.

I have just ordered parts from Jeff. The kit includes 6N6P tubes (those are cheaper than ECC99). But I noticed, that tube characteristics of 6N6P are a little bit diffrerent than those of ECC99.
With the same grid voltage and the same plate voltage, anode current of 6N6P will be higher. At -2.1V at cathode (determined by three diodes in series), and 120V anode voltage, the current of 6N6P will be about 28mA. At the same conditions, the current of ECC99 will be around 24mA. This is still well within those tubes max specifications, but in case of 6N6P, dissipated power (almost 7W) will be dangerously close to the max power specification of 8W, which may affect lifespan of 6N6P in negative way. Is this a reason, why most people are using ECC99? I am planning to increase cathode bias of my 6N6Ps to 2.9V by adding another diode in series. This should lower the current to 24mA, as I see on the chart.

My second question is why the Regal's mod specifies using only ECC99 in output stage. The output stage is completely separated from input stage, the only connection is for audio signal via capacitors 100nF. Since the modifications are made in input stage, how it can affect working point (DC) of output stage? Does it have something to do with gain?

My last question is what is the role of that electrolytic capacitor C1 10uF? Looks like fixed negative feedback, but I'm not sure. Does it make sense to replace it with film cap?

Maybe these questions were answered already on the forum, so I'd be sorry about duplicating them, but going through those >200 pages is a problem indeed.


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## vlb

Straight from memory so I might be off... I think the reason to use ecc99 together with regals mod is to keep the total current within the PS limits. C1 is futterman feedback, but Im not clear on its purpose.


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## funch

In case anyone wants to build the Bijou, here is the home page from the Wayback Machine.

https://web.archive.org/web/20160624185944/http://www.cavalliaudio.com:80/pages/bijou


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## ndndjsiew

Yes, I am currently building Bijou. I have already found that page after some long search.
Not quite sure yet if it was worth to start that project though. I'll see (or I should say hear) when it's finished. Certainly, there's some fun in working on a project like that.
But on the other side, you can buy ready made tube headphone amps (on Massdrop for example), which have great reviews, for a price comparable with the price of parts needed to build Bijou. 
How those Chinese are able to do this so cheaply, I don't know. Even considering lower cost per unit when something is made in big quantities an low labour cost, It"s still amazing.


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## fernan

ericj said:


> The ECC99 is a modern tube from JJ. It would have a big red JJ logo on it. It's based on the 6n6p, but has higher plate resistance.
> 
> If there's no JJ logo, it's probably 6n6p-i or 6n6p-ev, and the only difference there is the heater current iirc. My heater supply is doing just fine with a pair of 6n6p-i at almost an amp each and a pair of 6n1p at 600ma each along with the EZ81.
> 
> 6h30-pi was a premium option and i doubt glassjar ever sold any. You would have noticed at $30/tube.



K501 Respecting the values R katodo, original circuit wiht nos 6n6p 70s (FOTON It has slight improvement. and shooting the price,
6n6p-i or -ir I like less) 
6H30p-dr NOS year 76 (now they cost fortunes), for me it is magical and crystal clear (for some perhaps, very analytical, fast ....) 30 $ 6h30p-EB sowtec (EH I read it's the same just gifted pins)  they sound just like garbage in this circuit ...... and I can not recommend. (russky 6h30p and  -DR 90s or modern ????? but not 30$

6n1p-EB also 70 years, more than all ECC88, E88CC, CCa, 6922 (BOY amperes I have not tried) 
heaters I have reserve and Brimar CV5072 ez81, (any EZ81 NOS, I do not perceive differences)

The Regal MOD, did not give me as good sound as my configuration, possibly for the 6N6P, I would prefer to spend my scarce resources in better caps than in ECC99s.
I'll look for a better operating point by testing a diode more than they suggest for 6H6. If I do not go to the limit, or go down to the 220V circuit, they really run very hot!


Best regards


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## fernan (Mar 10, 2019)

En esta PSU Mod Adamus, ¿debería funcionar con EZ81 y disipadores más grandes para TIP50?

¿O mantener el + HT original para los filamentos? Para 6,3V 4A tengo CT, desaparecen las resistencias 100R, 64K y 10uF ... ¿Alguna sugerencia?


y / o doble fuente de alimentación, estoy preparando el amplificador balanceado?

 Me alegra ver este hilo abierto después de la desaparición de la web anterior Cavalli

Muchas gracias


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## Zulkr9

Anybody know how to contact glassjar audio, seems to be unresponsive


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## bhjazz

Zulkr9 said:


> Anybody know how to contact glassjar audio, seems to be unresponsive


That is, unfortunately, common.  I have not checked in with him in a number of years but his site still appears active.  Give him another try or two.


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## Zulkr9

also would ike to know is it worth it buidling the bijou, or is the crack better


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## Martinrm

Who's still enjoying their Bijou? Was getting ready to sell mine since I had switched to SS for the past few months. Plugged it in and forgot why I loved my Bijou so much. Now it's my daily driver again.


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