# Modding the Bel Canto DAC2



## Edwood

Well, I'm feeling that itch. (and I feel like modding something too.) 
	

	
	
		
		

		
			





 I opened up my Bel Canto DAC2 and had a looksy at what could be modded.
 Took lots of pics and wrote down specs of as many things I could see. Particulary caps.

 DAC BOARD

























 Looks like it's soldered by hand. Lots of crooked SMD components.

















 So, does there look like there is anything worthwhile to mod here?

 Got pics of the PSU and Caps coming up next.

 -Ed


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## Edwood

DAC BOARD
 Electrolytic Caps





 (x5)Nichicon Muse 100uF 25V 10.19mm(diameter) x 16.26mm, 5mm pitch





 (x2) Generic? 1000uF 16V 10.24mm(diameter) x 16.26mm, 5mm pitch


 PSU BOARD

 Transformers 





 Amveco 
 115V 115V, 16VA + 16VA, 7V 7V
 115V 115V, 5.0VA = 5.0VA, 9V 9V





 Notice the switch for switching between 115V and 230V.







 Electrolytic Caps





 Generic? 2200uF(M) 25V
 NRSA CE85 degrees C 9722
 16.20mm(diameter)(18.25mm - 19.5mm max) x 26.17mm H (37.4mm Max height, 8mm Pitch

 Swapping out the PSU power resevoir caps looks like a no-brainer, but there isn't a whole lot of room in there.

 -Ed


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## dip16amp

Quote:


  Originally Posted by *Edwood* 
_Well, I'm feeling that itch. (and I feel like modding something too.) 
	

	
	
		
		

		
		
	


	




 I opened up my Bel Canto DAC2 and had a looksy at what could be modded.
 Took lots of pics and wrote down specs of as many things I could see. Particulary caps.

 ...

 So, does there look like there is anything worthwhile to mod here?

 Got pics of the PSU and Caps coming up next.

 -Ed_

 


 I assume you've read the modifications that Empirical Audio does on it? His web page explains alot of things wrong with it and what changes he made. That would be a good starting point.


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## Edwood

Quote:


 Mod Details:
 Rectifiers are replaced with FRED's 
 Main filter caps replaced with Nichicons 
 Bulk decoupling caps replaced with Black Gates 
 Improve Post-DAC analog filtering 
 Add high-frequency decoupling caps 
 Remove final analog filters 
 Eliminate the hum 
 Install high-performance pulse transformer 
 Tune transmission-lines 
 Optional high-performance power harnesses 
 Optional modded Superclock3 
 Optional modded SuperTurboclock3 
 

Holy Crap, his mods cost more than the Bel Canto DAC2 itself.

 Hmmm. Replacing the Recitifiers with Fast Recovery Diodes seems a bit trickier than just replacing caps. Would this mod be worthwhile? Certainly cheaper than replacing caps.

 Gonna have to study the board a bit more.

 High Performance Pulse Transformer? Will one fit in place of the Avemco's that are in there right now?

 Tune transmission lines? LOL, is he tweaking a car, or a DAC? SOme of these "tweaks" smell a bit of snake oil, well, motor oil at least.

 -Ed


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## Edwood

Quote:


  Originally Posted by *Edwood* 
_
 Electrolytic Caps
 Generic? 2200uF(M) 25V
 16.20mm(diameter)(18.25mm - 19.5mm max) x 26.17mm H (37.4mm Max height, 8mm Pitch

 Swapping out the PSU power resevoir caps looks like a no-brainer, but there isn't a whole lot of room in there.

 -Ed_

 

Looks like Blackgate FK Series 35V 2200uF 18x35mm will fit perfectly for the PSU. Good thing there are only three. 
	

	
	
		
		

		
		
	


	




 I'll have to check for the lead spacing, but it shouldn't be to difficult to bend them to fit.

  Quote:







 (x2) Generic? 1000uF 16V 10.24mm(diameter) x 16.26mm, 5mm pitch 
 

Are these (the light blue ones) the coupling caps?
 Looks like Blackgate FK Series 16V 1000uF 16x31.5mm won't fit.

 -Ed


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## lan

Quote:


  Originally Posted by *Edwood* 
_High Performance Pulse Transformer? Will one fit in place of the Avemco's that are in there right now?_

 

I believe that's the transformer for the digital input not the power transformer.


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## Edwood

Would it be worthwhile swapping out the Nichicon Muse caps with Blackgate FK's?

 -Ed


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## lan

Well it's your money and it's valuable experience to try various caps out. I wouldn't try it on such an expensive project though. I like to go one step at a time and appreciate the sound. It not valueable experience to me to mod everything all at once. I like to tailor the sound the way I like it.


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## Edwood

Would the PSU resevoir caps be better to swap out first, or the coupling? (the little blue ones 16V 1000uF) caps?

 -Ed


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## lan

For me it's always best to start from the very beginning so it's PSU caps first. But if those output coupling caps are for blocking DC and you have them in your amps, it's redundant to have them in both places, i'd remove them. But are you sure they are output caps?


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## Edwood

Quote:


  Originally Posted by *lan* 
_For me it's always best to start from the very beginning so it's PSU caps first. But if those output coupling caps are for blocking DC and you have them in your amps, it's redundant to have them in both places, i'd remove them. But are you sure they are output caps?_

 

They look more like input coupling caps to me. They're much closer to the inputs. But I could be wrong.

 Wouldn't be the first time. 
	

	
	
		
		

		
		
	


	




 Should I have posted this in the DIY forum? Not that I don't appreciate your company, Lan, but I'm sure there are many others (coughGlassmanWodgyetccough) that could chime in. 
	

	
	
		
		

		
		
	


	




 Of course there would be the Rickmonster laying down his usual smackdown when he finds out I don't know What I'm doing. 
	

	
	
		
		

		
		
	


	




 -Ed


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## lan

Input? 
	

	
	
		
		

		
		
	


	




 I don't know what's going on with that board. Just commenting on your comments 
	

	
	
		
		

		
		
	


	




 Havn't heard from the rickster in a while.

 BTW where's the multiwave board you're supposed to send me? 
	

	
	
		
		

		
		
	


	




 I'll be needed it since i'll be moving into a sketchy powered place. i have to rectify that.


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## Edwood

Quote:


  Originally Posted by *lan* 
_Input? 
	

	
	
		
		

		
		
	


	




 I don't know what's going on with that board. Just commenting on your comments 
	

	
	
		
		

		
		
	


	




 Havn't heard from the rickster in a while.

 BTW where's the multiwave board you're supposed to send me? 
	

	
	
		
		

		
		
	


	




 I'll be needed it since i'll be moving into a sketchy powered place. i have to rectify that._

 

LOL, I still can't find it. Funny you asked. I actually looked around for it today.

 I've still got a pile of crap to go through. Hopefully my wife didn't throw it away. But she knows better to throw away anything that looks electronic. 

 -Ed


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## lan

Quote:


  Originally Posted by *Edwood* 
_LOL, I still can't find it. Funny you asked. I actually looked around for it today._

 






 <- WIth my special antennae I know what you're doing 
	

	
	
		
		

		
		
	


	




 You should also convince somebody to mod the DAC1 and then compare again.


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## Edwood

Quote:


  Originally Posted by *lan* 
_





 <- WIth my special antennae I know what you're doing 
	

	
	
		
		

		
		
	


	




 You should also convince somebody to mod the DAC1 and then compare again. 
	

	
	
		
		

		
		
	


	


_

 

LOL, I'm listening to mine right now. 
	

	
	
		
		

		
		
	


	




 They must tune into each other over great distances. 
	

	
	
		
		

		
		
	


	




 OK, enough derailing this thread, YGPM. 
	

	
	
		
		

		
		
	


	




 -Ed


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## Iron_Dreamer

Quote:


  Originally Posted by *lan* 
_You should also convince somebody to mod the DAC1 and then compare again. 
	

	
	
		
		

		
			



_

 

Hehe, cough, well it HAS been a while since I modded anything that didn't say EMU


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## Glassman

woohoo I'm commin' 
	

	
	
		
		

		
		
	


	




 what a delicious food you prepared for me!

 first of all, very nice piece of engineering! kudos to the guys at Bel Canto! I'm somewhat lost on the Spartan thingie, I have no idea why it's neccessary there, looks like the most basic Spartan in the family, so maybe it's really just controlling and routing, but why? those components can happily run on their own without any control, the ASRC has to be operating in asynchroneous mode, so whatever input samplerate the DIR1703 locks on will be input into the AD1896, which is slaved to clean 192kHz clock divided from that big oscillator.. well the clock has to be divided somewhere, but that could have been done by simple logic.. I'm really curious about the Spartan there..

 adding digital isulation transformer certainly a good idea, you can get one from Scientific Conversion for $15-16 in unit quantity, payed by PayPal.. the application circuit is simple.. I'm not shure how much will be gained by using it because all those jitter eliminating parts there like S/PDIF receiver with the best jitter attenuation and ASRC chip.. you can try that though.. I would also replace the caps in digital department with Sanyo OSCON SC/SH series if they're not already there, they look much like those light blue ones already there.. so far for the digital..

 in the analog part of the board, it's really a nice kindergarden 
	

	
	
		
		

		
		
	


	




 Empirical guy most likely tries to simplify analog lowpass filtering as much as possible, nothing against of course.. he also decided to skip the second opamps.. it depends.. anyway, you can play with the sonic signature of the Bel Canto easily by swaping the opamps, you can start with OPA627AU.. this part of the modding should have the most obvious impact on the final sound and you should be able to 'personalise' the sound of whole unit, will be fun! go fetch some browndogs Ed


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## Edwood

Is this the analog stage OP amps? I don't recognize it. I couldn't find info about it.

 4130C
 08T
 A69H

 Texas Instruments, obviously.

 -Ed


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## Edwood

Quote:


  Originally Posted by *Glassman* 
_I would also replace the caps in digital department with Sanyo OSCON SC/SH series if they're not already there, they look much like those light blue ones already there.. so far for the digital.._

 

Wow, can't seem to find Sanyo OSCON's for sale anywhere from the usual suspects (Mouser, Digikey, etc.). 

 Would Blackgates FK or NX series be better replacements?

 -Ed


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## Glassman

BG-NX also good..

 hey, what's that Motorola IC??


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## Edwood

Labeled pics:




































 -Ed


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## Edwood

Quote:


  Originally Posted by *Glassman* 
_hey, what's that Motorola IC??_

 


 Motorola
 MC68HC
 908GP32CFB
 3J20XHCX0007


 -Ed


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## dip16amp

The 4130C maybe a TI THS4130.
 The 88INA 134UA maybe a Burr Brown INA134.
 The BBOPA 2604AU maybe a Burr Brown OPA2604.


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## Glassman

I have to admit I don't get it really.. the Spartan there is fine, but what the hell is that microcontroller for!?

 three different opamps, looks like a mixture of three different flavours contributing to the final sound.. interesting..


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## Edwood

Gah!

 Figures. Kyoto Electric doesn't update their site. They barely have any Blackgates in stock.

 How long does it usually take Rod to backorder his stuff?

 Should I order from Partsconnexion instead?

 -Ed


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## dip16amp

Quote:


  Originally Posted by *Glassman* 
_I have to admit I don't get it really.. the Spartan there is fine, but what the hell is that microcontroller for!?

 three different opamps, looks like a mixture of three different flavours contributing to the final sound.. interesting.._

 

The PCM1738 is software controlled by the microcontroller.


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## Edwood

What do you suppose was supposed to go there J14 is?






 -Ed


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## PhilS

Quote:


  Originally Posted by *dip16amp* 
_I assume you've read the modifications that Empirical Audio does on it? His web page explains alot of things wrong with it and what changes he made. That would be a good starting point._

 

 Has anybody heard the Empirical Audio mods or seen any reviews of it? I am considering having this done, as I am not a DIY'er.


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## lan

Quote:


  Originally Posted by *Edwood* 
_Gah!

 Figures. Kyoto Electric doesn't update their site. They barely have any Blackgates in stock.

 How long does it usually take Rod to backorder his stuff?_

 

Are blackgates really gone or can he order more?


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## Glassman

Quote:


  Originally Posted by *dip16amp* 
_The PCM1738 is software controlled by the microcontroller._

 

why microcontroller, Spartan can handle that with ease, that's my question.. certainly not only PCM1738 can be and is software controlled..

 re: J14, maybe headphone output?


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## Edwood

Quote:


  Originally Posted by *PhilS* 
_Has anybody heard the Empirical Audio mods or seen any reviews of it? I am considering having this done, as I am not a DIY'er._

 

http://www.audiocircle.com/circles/v...ic.php?t=11299

  Quote:


  Originally Posted by *Emprical Audio* 
_Mods done to the following so far: 

 1) input pulse transformer added and impedance matched to 75 ohms - eliminated capacitive coupling - there was actually a 150 ohm matching resistor there. Does not make sense to me.... 
 2) some transmission-line terminations adjusted 
 3) Nichicons replaced generic caps on power supply board 
 4) FRED's replaced rectifiers on power supply board 
 5) Post-DAC filtering caps upgraded 
 6) bulk decoupling caps changed from Nichicon Muse to Black Gates 
 7) high-frequency decoupling caps added to analog stages 
 8 ) Digital input RCA isolated from ground 
 9) more Black Gate bulk decoupling caps added _

 


 Have the mods done, and we can compare. 
	

	
	
		
		

		
			





 -Ed


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## dip16amp

Quote:


  Originally Posted by *Glassman* 
_why microcontroller, Spartan can handle that with ease, that's my question.. certainly not only PCM1738 can be and is software controlled..

 re: J14, maybe headphone output?_

 

You're right, the Spartan does look to be controlling the DIR1703, ASRC, and PCM. The microcontroller looks like it's providing clocking functions.


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## Edwood

Quote:


  Originally Posted by *lan* 
_Are blackgates really gone or can he order more?_

 

Rod sure is slow to respond. Although not nearly as slow as THLaudio. They usually take 2-5 days to respond.

 Sounded like he could order more. Not sure though.

_"Hello Edwin,

 I have 4 of the 100uf 25V FK. The space is about 5mm. (I have tons of 
 100uf 50V FK if you wanted those instead.)
 I do have the two 1000uf 16V FK and the space is about 7mm.
 The 2200uf 35V FK have been very slow to come in, but am hoping for 
 more.

 Hope this helps.
 Rod"_

 -Ed


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## Zoide

You guys are EVIL. Stop this.

 I'm soooo satisfied with my precious Bel Canto and now you're talking about modding it.

 Shame on you, the devils of upgradeitis! I shall resist!


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## Edwood

Is it even remotely worthwhile swapping out the crystal oscillator with Audiocom's Superclock 3? I thought the Bel Canto DAC2 already had jitter reducing abilities.

 Don't know where it could fit. There looks like there was supposed to be a daughterboard near the little "tin can". Is that were it can be interfaced?

 Am I reading it correctly?
 9.83MHz?

 Don't think ReferenceAudioMods carries that frequency. 

 -Ed


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## lan

Quote:


  Originally Posted by *Edwood* 
_I thought the Bel Canto DAC2 already had jitter reducing abilities._

 

Well jitter reducinig in the sense that it reduces all incoming jitter to that of what it has internally. There's no such thing as zero jitter. So naturally if you enhance what's inside, it should be better.


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## PhilS

Quote:


  Originally Posted by *Zoide* 
_You guys are EVIL. Stop this.

 I'm soooo satisfied with my precious Bel Canto and now you're talking about modding it.

 Shame on you, the devils of upgradeitis! I shall resist!




_

 

 I know what you mean. I love the Bel Canto in my setup and the thought that it could be even better is every enticing. I am going to do some more research and thinking about this.

 P.S. You know resistance is futile!


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## Edwood

Why is the middle lead not connected on the LM1117 regulator?

 This is the one pictured above, right?
http://www.national.com/pf/LM/LM1117.html


 Can it be replaced with an Audiocom Super Regulator? Or would it be a Super waste of money?






 -Ed


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## Glassman

no, of course that Motorola micro does have nothing to do with clocking, it's again Spartan's task to divide the 24.576MHz masterclock and send it towards the ASRC chip.. that 9+MHz crystal is just for running the Motorola IC itself.. you might try to replace that 24.576MHz oscillator though..


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## Edwood

Quote:


  Originally Posted by *PhilS* 
_I know what you mean. I love the Bel Canto in my setup and the thought that it could be even better is every enticing. I am going to do some more research and thinking about this.

 P.S. You know resistance is futile! 
	

	
	
		
		

		
		
	


	


_

 

LOL, I'm the guinea pi...... hamster, right? 
	

	
	
		
		

		
		
	


	




 Well, you guys are more than welcome to come over for a mini-meet to compare stock vs. modded if I am successful.

 -Ed


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## Edwood

Quote:


  Originally Posted by *Glassman* 
_no, of course that Motorola micro does have nothing to do with clocking, it's again Spartan's task to divide the 24.576MHz masterclock and send it towards the ASRC chip.. that 9+MHz crystal is just for running the Motorola IC itself.. you might try to replace that 24.576MHz oscillator though.._

 

So, just desolder the existing 24.576MHz oscillator and solder in the Super Clock? WIth some creative mounting to get it to fit and be secured? 

 What are all those empty areas to the left and top of the 9+MHz crystal? There is a row of pins to the top of it. And empty rows of holes for some kind of interface?

 -Ed


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## Edwood

Quote:


  Originally Posted by *dip16amp* 
_The 4130C maybe a TI THS4130.
 The 134UA maybe a generic OPA134.
 The BBOPA 2604AU maybe a Burr Brown OPA2604._

 

Looks like the BB OPA2604AU is my main target for OPAmp rolling? Plenty of space for a SOIC to DIP8 Browndog. 

 What about the others, like the TI THS4130's? (x2)

 -Ed


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## dip16amp

Quote:


  Originally Posted by *Edwood* 
_Looks like the BB OPA2604AU is my main target for OPAmp rolling? Plenty of space for a SOIC to DIP8 Browndog. 

 What about the others, like the TI THS4130's? (x2)

 -Ed_

 

Can you wire balanced outputs from those differential amp chips?


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## Edwood

Quote:


  Originally Posted by *dip16amp* 
_Can you wire balanced outputs from those differential amp chips?_

 


 That would be my next question. Is it possible to wire out balanced outputs?

 Perhaps right after the two TI THS4130's from J17 and J13? (see the three holes?)

 Maybe if the AD1896 has enough juice I could bypass the analog output stage altogether?

 -Ed


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## Glassman

heh AD1896 is ASRC, PCM1738 is DAC 
	

	
	
		
		

		
		
	


	




 and it's a current output DAC so no bypassing possible, you need to keep at least the opamps closest to it 
	

	
	
		
		

		
		
	


	




 but you can try whatever single channel opamp you like.. I'm not shure it the OPA2604 is actually used in signal path to the RCA jacks, check it first..


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## PhilS

Quote:


  Originally Posted by *Edwood* 
_LOL, I'm the guinea pi...... hamster, right? 
	

	
	
		
		

		
			





 -Ed_

 

The best part is that we get to live vicariously through you as you emark on this adventure. Please keep us up to speed as you go along. This should be very interesting.


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## dip16amp

The THS4130 seems to be the I/V conversion opamps and pin 4 is the positive output. Pin 5 is the negative output, so find out were it is going.


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## Edwood

Quote:


  Originally Posted by *Glassman* 
_heh AD1896 is ASRC, PCM1738 is DAC 
	

	
	
		
		

		
		
	


	




 and it's a current output DAC so no bypassing possible, you need to keep at least the opamps closest to it 
	

	
	
		
		

		
		
	


	




 but you can try whatever single channel opamp you like.. I'm not shure it the OPA2604 is actually used in signal path to the RCA jacks, check it first.._

 

LOL, duh. *smacks forehead*.

 Yeah, looks like the traces loop back at the least. They sure do look like they dead end. It might very well be that the OPA2604 was meant for a headphone output at J14.


 -Ed


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## Mr.Radar

You should keep in mind when reverse-engineering the PCB that it has 4 layers*, so not all the traces are visible.

 *See the bottom of Page 4 in the user manual.


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## Edwood

Quote:


  Originally Posted by *Mr.Radar* 
_You should keep in mind when reverse-engineering the PCB that it has 4 layers*, so not all the traces are visible.

 *See the bottom of Page 4 in the user manual._

 


 Guess I have to be careful if I start drilling holes or something.

 I'll hold the PCB up to the light to be sure.

 -Ed


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## Edwood

Pics of the Diodes on the PSU board.
















 As far as I can tell, they are all the same and have printed on them:

 TCI
 TSR150

 So what can I replace these with?

 Or should I leave them alone?

 -Ed


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## Edwood

I've heard of replacing diodes with soft recovery ones?

 Any idea what the specs are on those diodes pictured above?

 -Ed


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## audioengr

Quote:


  Originally Posted by *Edwood* 
_Holy Crap, his mods cost more than the Bel Canto DAC2 itself.

 Hmmm. Replacing the Recitifiers with Fast Recovery Diodes seems a bit trickier than just replacing caps. Would this mod be worthwhile? Certainly cheaper than replacing caps.

 Gonna have to study the board a bit more.

 High Performance Pulse Transformer? Will one fit in place of the Avemco's that are in there right now?

 Tune transmission lines? LOL, is he tweaking a car, or a DAC? SOme of these "tweaks" smell a bit of snake oil, well, motor oil at least.

 -Ed_

 

Snake-oil? I suggest you ask an experienced digital engineer about transmission-line effects.

 Steve N.
 Empirical Audio


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## audioengr

Quote:


  Originally Posted by *lan* 
_Are blackgates really gone or can he order more?_

 

Black Gates are gone. They are not manufacturing them since last year. Most of the modders that like them, including myself bought most of them up.


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## audioengr

Quote:


  Originally Posted by *Edwood* 
_





 Why is the middle lead not connected on the LM1117 regulator?

 This is the one pictured above, right?
http://www.national.com/pf/LM/LM1117.html

 Can it be replaced with an Audiocom Super Regulator? Or would it be a Super waste of money?






 -Ed_

 

LM117 is an adustable regulator. The modules from Audiocom are usually fixed voltages.

 The middle leg is not connected because it is the same as the tab, which is connected.


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## audioengr

Quote:


  Originally Posted by *Edwood* 
_LOL, duh. *smacks forehead*.

 Yeah, looks like the traces loop back at the least. They sure do look like they dead end. It might very well be that the OPA2604 was meant for a headphone output at J14.


 -Ed_

 

I've decided to give you some guidance: From what I recall, the OPA2604 is a DC-servo to eliminate DC-offset and allow DC-coupling. Changing it will not have much effect.


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## Edwood

Thanks for the advice. 
	

	
	
		
		

		
		
	


	









 Is it possible to wire out balanced outputs?

 Perhaps right after the two TI THS4130's from J17 and J13? (see the three holes?)


 -Ed


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## 00940

The THS4130 are there for I/V indeed. The only suitable alternative would be the OPA1632. And from some accounts, those chips could be only rebranded ths4130, figures are awfully similar. The bel canto I/V is as follow : 






 From : http://www.diyaudio.com/forums/showt...230&highlight=

 A nice way to perform I/V on differential current out dac. Something I'm strongly considering on my own dac.


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## 00940

there's a typo on the schematic btw, INA130 should read INA134. And it has nothing to do with an OPA134, it is a balanced to unbalanced line driver. No substitute that I know of.

 The OPA2604 is indeed used to provide offset correction on the reference pin of the INA134.

 It would be difficult to alter the I/V stage. A radical mod would be to mount a small pcb, with a fully different outputstage, powered from the +/-9V supplies.

 Analog filter is really kept at the minimum (with the ad1896 and the OS on the dac, there's a minimal need for it), so it makes your life easier. You could take balanced out after the ths4130. It outputs some serious current 
	

	
	
		
		

		
		
	


	




 PS: so funny, this dac is so similar to what I'm considering building myself. I just exchange DIR1703 for CS8416 (dir1703 being sadly discontinued) and the PCM1738 for the PCM1794.


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## Edwood

So that means that balanced analog output is possible.

 So that would mean that J17 and J13 is where I can wire balanced outputs to?

 There is just enough room to fit two 3pin XLR's in the front panel. I will have a nice custom one made via FPE. But I have a aluminum sheet I can use in the meantime.

 -Ed


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## Edwood

Ordered some 2200uF 35V Blackgate FK's. Will be swapping out those PSU resevoir caps first.

 Balanced output addition next if it is possible. 

 -Ed


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## motherone

If you can't get a balanced output on board, you could always take the single ended output and run it through some opamps to create a balanced output.

 Your other option is to look at tapping pins 4 & 5 from THS1431's and running that to a small PCB to create a balanced out (maybe 2x BUF634's per channel or something). This is from my meager understanding of how this stuff works, and it's difficult without seeing a schematic on how it's being done


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## Edwood

Mods, could you please move this thread to the DIY forum?

 I have some troubleshooting that would be better served in that forum. Plus the poll from my question about modding threads would be that this thread does belong in the DIY forum.

 -Ed


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## Edwood

I have Blackgate FK's in the PSU. All the voltages are correct.

 The Signal Lock lights up green, but No Sound from analog outputs. 
	

	
	
		
		

		
		
	


	




 Crap. What went wrong? 





 -Ed


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## lan

Uh oh...

 Did you put it back together ok? Did you put the original caps back in?


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## Edwood

Blackgates





 Stock





 Yep, I double, triple, and quadruple checked polarity. 
	

	
	
		
		

		
		
	


	




 -Ed


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## Edwood

I'm running it outside it's case. Going to add a sheet of Teflon on the bottom of the DAC board just in case. The Caps have just a few millimeters of clearance as you can see.

 I'm running it outside it's case, to make sure there aren't any shorts. But nada.

 Put it in it's case. No difference.

 ARGH!

 -Ed


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## lan

Did you check with multimeter power supply is outputting something?


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## Edwood

The DAC board's LED lights up and turns green when it gets a signal lock. But still no analog output. 

 -Ed


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## Edwood

Here's a pic of the teflon sheet I added to the bottom of the DAC board's "tray".

 -Ed


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## Edwood

Well, I removed the Blackgates and soldered the stock caps in place. Still no analog output. So it's probably not those capacitors that are the problem.

 Here's some more symptoms:

 1. Noise level (hiss) is a bit louder than I remember when cranking the volume all the way up (at really dangerous levels, monitoring with MS-2's) At least the noise level is a bit louder than the Grace m902's DAC. 

 2. When the Bel Canto is hooked up to a Pimeta, I can hear audible static noise when turning the volume pot up. (Alps Blue Velvet). I don't notice any such static with the Grace m902. This static noise is not present with other sources hooked up to it or with no source hooked up.

 I'm thinking perhaps to try replacing the main analog output OP Amp. 

 Any idea which one(s) could be replaced? 
 Going to use Browndog adapter to allow OP Amp rolling, of course.

 -Ed


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## 00940

Did you read what I wrote above ? There is NO possible opamp rolling.

 The first opamps are THS4130, and are about the one and only of their kind (except the very similar OPA1632). They are fully differential opamps.

 The second soic8 chips are INA134, balanced to unbalanced receivers. Not compatible with opamps.

 The opa2604 is a reference/servo. No need to change it.


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## 00940

btw, what are the voltage at the pins 1 and 8 of the THS4130, at the pins 4 and 7 of the INA134 ?

 Your problem is clearly on the DAC board. I hope for you that you didn't fry a logic chip by touching it while being full of static.


----------



## Edwood

Quote:


  Originally Posted by *00940* 
_btw, what are the voltage at the pins 1 and 8 of the THS4130, at the pins 4 and 7 of the INA134 ?

 Your problem is clearly on the DAC board. I hope for you that you didn't fry a logic chip by touching it while being full of static._

 

Where should I measure the ground from?

 I was careful, wearing an antistatic wrist strap. 

 -Ed


----------



## dip16amp

Quote:


  Originally Posted by *Edwood* 
_Where should I measure the ground from?

 I was careful, wearing an antistatic wrist strap. 

 -Ed_

 

The analog ground is on the output RCA connectors.


----------



## Edwood

[size=xx-large]YEEEEEES! IT'S ALIIIIIIIIIVE! IT'S ALIVE!!!!!![/size]

 I took the voltage readings on the chips above, the numbers looked good, and then I decided, what the hell? I plugged in the digital inputs and the analog outputs, and voila! Music! Weird.
 Maybe it needed the night to cool off of something? Even though I didn't solder a thing on the DAC board. 
 How do those voltages look?

 Oh well. Won't peer into the jaws of the equestrian present given to me.

 Going to let the Blackgates burn in before proceeding to other mods. 

 Thanks everyone. 

 And thanks in advance for the further problems I'll probably encounter down the road.......
 -Ed


----------



## Edwood

For burning in the PSU resevoir caps, do I need a load on the Bel Canto's analog outputs? 

 Couldn't I just keep it powered up?

 Or do I at least need a signal fed into the digital input?

 -Ed


----------



## lan

That's good to hear it's working again 
	

	
	
		
		

		
			





 The PSU caps should burnin with no signal but you might as well just play some music as you go along. Sometimes I find things to be immediately better. Can you tell if it's better already?


----------



## Crazy_D

Quote:


  Originally Posted by *lan* 
_That's good to hear it's working again 
	

	
	
		
		

		
		
	


	




 The PSU caps should burnin with no signal but you might as well just play some music as you go along. Sometimes I find things to be immediately better. Can you tell if it's better already?_

 




 When we used to use blackgate FK's (almost 2 years ago) I noticed it took a couple hundred hours for burnin. so be prepared for changes in sound. The Fk series in power supply has better bass over the STD series. As long as there is a voltage and load for the caps they will breakin, so leave it on for a couple weeks.


----------



## Syzygies

Quote:


  Originally Posted by *RAM East* 
_When we used to use blackgate FK's (almost 2 years ago)..._

 

Doug, what do you use now?


----------



## Crazy_D

Quote:


  Originally Posted by *Syzygies* 
_Doug, what do you use now?_

 


 Hi,

 We use the Jensen 4-pole caps and/or Rubycon ZA/ZL for power supply applications now. The Rubycon ZA/ZL is my ultimate first pick for power supply cap replacements, if the circuit cannot physically fit the jensen 4-pole caps, however I still use them for additonal amounts of decoupling. It is not the specs that ultimately count here, but rather the materials and implemenations used within the cap to produce a faster and more open sound over all the caps we have directly compared them against. The issue with the Jensen 4-pole caps is they are not for the amatuer diy'er to install as they are not a direct "plug and play" replacement (cap swapping) and require modifications to the circuit, additional mounting (large size, may not be mountable in some unit and you have to resort to the Rubycons) and additional wiring into the circuit.


----------



## Syzygies

Thanks!

 Let me note for others that your company sellsl these: Rubycon ZA, ZL Capacitors.

 I see recs for these elsewhere on the web; they're certainly priced better than Black Gates. However, I couldn't find a datasheet anywhere, and you don't give dimensions. Could you entice your web guy to give dimensions and/or a datasheet link! Thanks.

 Edit: Found the ZL, but it took some spelunking, I nearly gave up. Couldn't find the ZC series:
Rubycon ZL datasheet


----------



## Edwood

Send an email or call up Kyle at Reference Audio Mods West and ask which ones you want the dimensions for. 
	

	
	
		
		

		
		
	


	




 -Ed


----------



## Edwood

When upgrading the clock in this DAC, does this mean that I need to upgrade the clock in my source as well? 

 Would the PLL circuitry help much? Or is it still a garbage in, garbage out scenario?

 I am using an RME digi96/8 PAD sound card as my source.

 Would I need to upgrade my sound card as well? 

 -Ed


----------



## MisterX

Quote:


  Originally Posted by *Edwood* 
_
 TCI
 TSR150

 So what can I replace these with?

 Or should I leave them alone?

 -Ed_

 

TCI= TAITRON Components Incorporated 
 TSR150 = RECTIFIER - SCHOTTKY - 1A 50V IN D0-41 PKG


 That explains why they didn't bypass them.... 

 I would replace them.


----------



## lan

Well if your DAC is reclocking, a better clock would help. Although clocking the transport and DAC to same clock would be better, I'm not sure how you'd implement that here or if it's even feasible.


----------



## Edwood

What about slaving the clock? Would that be possible?

 -Ed


----------



## Glassman

of course, but it would be a major rework, you will basicaly bypass what's worth at least $1000 from the value of the whole Bel Canto.. but it would be absolute solution..


----------



## Edwood

OK, what about them diodes there in the PSU?

 -Ed


----------



## Edwood

Will any of these work:

http://www.partsconnexion.com/catalo...onductors.html

 Particulary, the IXYS 15A 1200V Ultrafast, Soft Recovery (HiPerFRED) Epitaxial Diode (trr = 40 ns; TO-220AC package) 

 -Ed


----------



## individual6891

You're probably sacrificing too much in terms of ampere rating compared to Trr..

 I use BYW29 (datasheet from STmicro) range of recovery diodes. Trr 25ns rated at 8A TO220AC packaged. They cost less than $1 each


----------



## 00940

replacing a schottky, you will probably will get a (very slightly) different sound. But probably not a net improvement. Change and see what you prefer.


----------



## Edwood

Whaddya suppose was supposed to go where those holes are?






 Some kind of filtering caps?

 Looks like they come from the AC input, right after the Voltage selection switch?







 -Ed


----------



## NotoriousBIG_PJ

Quote:


  Originally Posted by *RAM East* 
_Hi,
 ...._

 

Hi Doug,

 I purchased some capacitors from RAM and received the wrong parts. I sent the parts back at my expense. My requests for a partial shipping refund have been ignored and I would like an explanation why.

 Biggie.


----------



## Crazy_D

Quote:


  Originally Posted by *NotoriousBIG_PJ* 
_Hi Doug,

 I purchased some capacitors from RAM and received the wrong parts. I sent the parts back at my expense. My requests for a partial shipping refund have been ignored and I would like an explanation why.

 Biggie._

 


 Hi Biggie,

 I do not sell and send off any parts order from my location, I only do all the installs/R&D/website here, so I do not know whats going on. However, please send me a PM with the information (your name, order number, parts sent back and amount of shipping adjustment owed backed) and I will make sure this get corrected. I deeply apologize for the inconveinence and lack of communications from RAM West on this situation.


----------



## Edwood

OK, back on topic.......

 Here's a pic of the clocks on my transport (RME digi96/8 PAD).






 One clock is 24.5760 MHz. (which is the same frequency as the Bel Canto's Clock)
 The other is 11.2896 MHz.

 Which clock is used for digital output?

 *crossing fingers for 24.5760 MHz........*

 -Ed


----------



## Glassman

both of course! whenever you play something at 44.1/88.2 it is the 11.2896 MHz but when you play 48/96 it's the 24.5760 MHz one.. do the math yourself, it's as simple as dividing the frequency by either 44.1 or 48.. you Bel Canto resamples any input it gets to 48 multiple, in that particular case 4x48=192kHz, that's why there's just one fixed frequency..


----------



## Edwood

Quote:


  Originally Posted by *Glassman* 
_both of course! whenever you play something at 44.1/88.2 it is the 11.2896 MHz but when you play 48/96 it's the 24.5760 MHz one.. do the math yourself, it's as simple as dividing the frequency by either 44.1 or 48.. you Bel Canto resamples any input it gets to 48 multiple, in that particular case 4x48=192kHz, that's why there's just one fixed frequency.._

 

Jitter wise, does it matter whether or not the frequency is the same on both the DAC and transport?

 -Ed


----------



## Glassman

it will never be the same even if the nominal frequency will be the same, thats it.. unless you sync them together.. I dont know if its better for the ASRC to run with two almost same frequencies or if its better when the ratio is clearly different, but at least from the graphs in AD1896 datasheet its better when both clocks are almost the same, so yes you would likely get better results if you replaced the oscillator in your Bel Canto with 44.1 related clock.. the best approach though is to have the best clock available (superclock3?) in your DAC, feeding it back to your soundcard so that the card will run off it and thus be synced.. this way you will completely skip any jitter related problems between the data stored on your harddrive and your Bel Canto.. if ultimate is what you seek..


----------



## Edwood

Quote:


  Originally Posted by *Glassman* 
_it will never be the same even if the nominal frequency will be the same, thats it.. unless you sync them together.. I dont know if its better for the ASRC to run with two almost same frequencies or if its better when the ratio is clearly different, but at least from the graphs in AD1896 datasheet its better when both clocks are almost the same, so yes you would likely get better results if you replaced the oscillator in your Bel Canto with 44.1 related clock.. the best approach though is to have the best clock available (superclock3?) in your DAC, feeding it back to your soundcard so that the card will run off it and thus be synced.. this way you will completely skip any jitter related problems between the data stored on your harddrive and your Bel Canto.. if ultimate is what you seek.._

 

How would this be accomplished? Probably not easily since the Bel Canto DAC2 only has a digital input and not output?

 -Ed


----------



## Glassman

simply add S/PDIF output, that's the easiest part, you will also have to run the outputs from S/PDIF receiver directly to the DAC, that means skipping the ASRC and Spartan..


----------



## Edwood

Quote:


  Originally Posted by *Glassman* 
_simply add S/PDIF output, that's the easiest part, you will also have to run the outputs from S/PDIF receiver directly to the DAC, that means skipping the ASRC and Spartan.._

 

Would this "basicaly bypass what's worth at least $1000 from the value of the whole Bel Canto.. "?

 Or is there a way I can add perhaps a toggle switch to switch between "syncing" the clocks and using all of the Bel Canto standalone?

 -Ed


----------



## Glassman

yes it would, but that $1000 shout was just to stress that this is one significant part of the Bel Canto design and why is this DAC so popular.. nevertheless, it's not the last word in jitter battle, but there's really not much to do when you want to have a product that will work in standard consumer enviroment that means S/PDIF connection, no external clock syncing.. however since you're going the modding route, you can deal with it much effectively, in fact there's nothing that could be better than what I've described..

 it probably can be made switchable somehow, you basicaly need to switch four signals, that's most likely all you have to do..


----------



## Edwood

Kewl.

 I'm going to mod one step at a time. If I don't hear a significant improvement, or am still itching to improve it after the Clock upgrade, I may try a switchable clock syncing method you described.

 Thanks!
 -Ed


----------



## Iron_Dreamer

Well it's good to see that your beast came back to life there Ed. I'll be interested to see how it sounds now.


----------



## Edwood

I've ordered some HEXFRED Ultrafast soft recovery diodes and some small ceramic caps for snubbers/bypass. (not sure whether to filter for High or Low frequency noise) That will finish up the mods for the PSU board. 
 Then I'll move onto the DAC board. I'm still waiting on the 100uF 25V FK Blackgates. I may end up getting impatient and trying to fit the 100uF 50V FK's as they are much easier to find. They are the same height as the 25V ones, but are 2.5mm larger in diameter.
 The caps over by the digital section will be replaced by 1000uF 25V NX Blackgates (unless I can find something better?)







 I'll also add balanced outputs too. Probably before the Blackgates are in stock. I have a nice pair of Vampire XLR jacks on their way to me. 

 Last upgrade will be the Superclock 3 (probably). That is, if I haven't killed the Bel Canto by then...... 
	

	
	
		
		

		
		
	


	




 And a few more tweaks after that. Perhaps upgrade the voltage regulator(s?) on the DAC board. (Probably just the LM1117)

 -Ed


----------



## MisterX

I am wondering what the results of the first capacitor upgrade are..... 
 Comments?


----------



## Edwood

Well, having left it powered up with a signal lock nearly nonstop since, it's not a night and day improvement (what single mod is?). So far, the bass seems to have tightened up a bit. And everything sounds clearer, like the veil has been lifted a bit. Oh, wait. Isn't that the default thing to say? 
	

	
	
		
		

		
		
	


	




 Seriously, I am pretty skeptical, and the placebo effect is just too real. I'll have to listen to a stock Bel Canto DAC2 side by side with mine to really hear for sure.

 I just got the HEFREDs and snubber caps in from Digikey. So I will adding those shortly.

 -Ed


----------



## Edwood

Before HEXFRED Diodes:





 After HEXFRED Diodes:





 Because of the problems I had last time, I discharged the power supply and caps before plugging in the DAC board. (left less than 2VDC)

 Plugged in, and SUCCESS! 
	

	
	
		
		

		
		
	


	




 -Ed


----------



## Edwood

Pics of the Fully Completed PSU Mods.
















 HEXFRED with Snubber/bypass Ceramic Cap. 





 -Ed


----------



## lan

so? what did you think of it? inquiring minds want to know!


----------



## Edwood

Unless the Blackgates have suddenly broken in, I'd say the HEXFRED diodes and Snubbers have made a more noticeable difference.

 Particulary in high frequency response. Bass is tighter too. I have always liked the Bel Canto's stronger bass output, but it was a bit on the boomy side. Sounds like I can pick out more details and instrument separation better too.

 Of course this could all be a placebo effect. I'll have to compare to a stock Bel Canto DAC2 to be absolutely sure.

 *edit* Just listening to Iron_Dreamer and mine's favorite percussion test song, Dream Theater "6:00" (the drummer sounds like he has 1000ft arms, LOL). Definitely makes my Bel Canto sound more different than the Grace m902's DAC. The m902 is quite lifeless in comparison now.

 -Ed


----------



## MisterX

What's next on the list?


----------



## Edwood

Going to move onto the DAC board

http://img.photobucket.com/albums/v7...ntoDAC2_15.jpg

 1. Add balanced output.
 2. Upgrade DAC board caps to Blackgates (100uF 25V FK's and 1000uF 25V NX's)
 3. Upgrade Voltage Regulator (just the LM1117 ?)
 4. Upgrade clock to Superclock 3.


 Leaving the most expensive upgrade for last.


----------



## skyskraper

what are u planning on using for the balanced out?


----------



## Edwood

Quote:


  Originally Posted by *skyskraper* 
_what are u planning on using for the balanced out?_

 

99.99% 24awg Telfon insulated Solid Silver braid to Vampire XLR panel mount jacks. 
	

	
	
		
		

		
		
	


	




 There is just enough room in the front panel. Such a weird layout the DAC2 has. I may end up recasing the entire thing.

 -Ed


----------



## skyskraper

oh so you're not actually adding a cold signal to the positive and ground?


----------



## Edwood

See J17 there?

 That's where one of the balanced outputs will be coming from.

 There is signal, inverted signal, and ground.

 -Ed


----------



## skyskraper

awesome 
	

	
	
		
		

		
		
	


	




 so easy. i thought u were adding an op amp stage to invert the signal at one point hehehe


----------



## Edwood

Yup. It's already there. 

 This mod is a no brainer. 




 -Ed


----------



## 00940

why would you change the LM117 ? It looks like it only feeds the digital section. 

 What are U16 and U27 near the DAC chip ?

 You could probably try to trace the voltage going out of the chips at the top, no1a and no2a, they look like the regulators for the analog output stage.


----------



## Edwood

Quote:


  Originally Posted by *00940* 
_why would you change the LM117 ? It looks like it only feeds the digital section. 

 What are U16 and U27 near the DAC chip ?

 You could probably try to trace the voltage going out of the chips at the top, no1a and no2a, they look like the regulators for the analog output stage._

 












 So it would be better to upgrade the regulators for the analog ouput stage rather than the digital section?

 -Ed


----------



## MisterX

Quote:


 What are U16 and U27 near the DAC chip ? 
 



http://www.national.com/pf/LP/LP2951.html


----------



## 00940

Thanks 
	

	
	
		
		

		
		
	


	




 Allright, Edwood, could you give us the voltages for the pins of those chips inside the red circles ? 











 Your best regulator should be on the pins 28, 24, 23 of the dac chip (the one inside the rectangle), since those feed the actual DAC. Can you track to which regulator they're going ?


----------



## Edwood

Where should I measure the Ground from? Analog output ground, or power input ground?

 -Ed


----------



## 00940

there's no virtual ground in here, just take it where the 0V wire from the power supply connects on the DAC board. The ground on the RCA should be ok too.


----------



## Edwood

About to solder the wires in for balanced outputs at J13 and J17.

 How does this look?
 A1, C1 = Negative balanced signal
 B1, D1 = Positive balanced signal

 Looking at the top one, which is the Left Channel, do I need to add an SMD capacitor(tantalum?) to *C84* and *C82* ? 

 -Ed


----------



## Edwood

OK, I figured it out, here are the pin outs for balanced output.





 Soldered 99.99% 22AWG Solid Silver wire braid underneath the PCB.





 Testing. It works!!! 
	

	
	
		
		

		
		
	


	








 Balanced output works perfectly, but there is some attenuation. A good amount. But I still have enough gain with my Grace m902 to listen to the quietest of songs. But I'm maxed out at 90-99. 

 So far it sound like balanced output has a bit more treble extension. And everything sounds a little bit clearer. It is really difficult to do rapid A/B switching on my Grace m902 because of the volume difference.

 I will hopefully be getting in the Vampire XLR jacks tomorrow.

 And all the other Blackgates from THLaudio, whothehellknowswhen. 

 -Ed


----------



## skyskraper

did you try switching positive and negative signals to see if that stopped the attenuation? its been a while but i think i experienced that when i had hot and cold mixe up once....


----------



## Edwood

Quote:


  Originally Posted by *skyskraper* 
_did you try switching positive and negative signals to see if that stopped the attenuation? its been a while but i think i experienced that when i had hot and cold mixe up once...._

 

OK, I tried reversing positive and negative, and the volume difference is still there. I'm pretty sure I had it correct the first time, since when reversing it sounds a bit thin.

 Thanks for the suggestion though. At least we ruled that one out. I think the unbalanced stage just has some extra amplification I guess.

 -Ed


----------



## Edwood

OK, I took continuity reads for figuring out which regulator(s) to possibly upgrade.
 I color coded which parts had continuity with each other.






 What do you guys think?

 Looks like two are possible candidates.

 -Ed


----------



## 00940

can you give us voltage readings at the pins of U27 ?


----------



## Edwood

Voltage reads.











 -Ed


----------



## 00940

not an easy per datasheet circuit 
	

	
	
		
		

		
		
	


	




 Anyway, I think I could have identified the U27 : http://www.toko.com.hk/Catalog/semi/...ata70xxx-E.pdf . It could be a toko LDO regulator, 4.4V output. But I cannot get its use here. Seems like it's activated by the VCOM but it should give 4.4V, not the reading you got. 

 It would be interesting to trace back the "purple 5V" to its origin


----------



## Edwood

Can't figure out where the "purple 5V" goes. It does not have any continuity with any other regulators or the power inputs from the power supply.

 -Ed


----------



## Edwood

http://img.photobucket.com/albums/v7...ancdOutput.jpg

 What about the surface mount Caps?

 9D2
 10
 35E


 Should I replace them with better caps? Film caps maybe? What's their values? 10uF 35V? 35uF 10V? 

 Or should I just leave them alone?

 They are in the analog output stage.

 -Ed


----------



## Edwood

Finally got the Vampire XLR jacks in. 







 Here is a concept of what I'd like the new bezel to look like. I could make it with FPE, but I don't like the engraved/milled lettering. Anyone know of a place that can do one off Laser Etching from an image file?

 And yeah, I didn't match the Bel Canto logo font yet...... I can't figure out which font it is, I may have to make it from scratch in Photoshop.

 -Ed


----------



## Edwood

Rest of the Caps replaced with Blackgates.





















 Very very tight fit. There is literally less than one milimeter of clearance for the smaller black 100uf 25V caps. Should I insulate the tops of the caps from the inside of the case? Is there any risk of shorting from the top of the caps touching the metal inside of the case? Doesn't look like it would be a problem.

 -Ed


----------



## Edwood

First pass at new front panel prototype.
 This is all done with hand tools, a power drill, and jewelers files.





 All screws are stainless steel and countersunk now. 






 Not too happy with how some of the holes turned out. Particulary the Balanced output holes. They look like @ss. Going to need to have this CNC'd or laser cut for the final. Definitely thicker stock, maybe stainless steel if possible. Some tweaking to do on the layout, some of the holes don't line up perfectly as well.

 Other than that, it's working perfectly.

 -Ed


----------



## Edwood

Aluminum with brushed finish.











 Nice and purdy. 
	

	
	
		
		

		
		
	


	




 This aluminum is waaaay too soft to ever have it be a final product. But it is much easier to work with that's for sure. I'd like to use thicker metal for the next version. 

 Now I have to find a place to laser etch some graphics. 

 Oh, and there's still a few internal upgrades left, but I think I'll be letting this little guy burn in for now. (have been feeding music into it 24/7 )

 -Ed


----------



## Edwood

I replaced the crappy Vampire RCA jacks with Cardas monsters. More trouble that it's worth in retrospect. But at least they turned out nice.





 The signal wire is curled like that to allow some play since the center socket of the Cardas RCA jack rotates if you twist the RCA connector when it's in the jack. And I drilled a tiny hole in the Jack to solder the ground wire to.





 The two solder blobs closest to the end of the RCA jack are just there to hold the tabs in the holes I drilled. The only time I use solder as "glue".

 I ran into trouble when swapping out the SPDIF RCA jack. The extra mounting holes I drilled into the PCB were apparently touching the ground plane, so it was causing a short. So it wouldn't turn on. I removed the connector and I cut one too many of the tabs off, so it's barely hanging on now. But no more short and it works fine now.

 Man, I need to get a replacement for that Cardas BNC Jack, I ruined it. 
	

	
	
		
		

		
		
	


	




 Well, at least the rear RCA's work nicely. They look nice too. The stock Vampire jacks have a pretty thin plating, it was already coming off. 
	

	
	
		
		

		
		
	


	




 The Cardas jacks are much beefier. PITA to work with, of course. 

 -Ed


----------



## dsavitsk

Quote:


  Originally Posted by *Edwood* 
_Anyone know of a place that can do one off Laser Etching from an image file?_

 

I think this place can http://andersengraving.com/.


----------



## Edwood

Quote:


  Originally Posted by *dsavitsk* 
_I think this place can http://andersengraving.com/._

 


 Thanks!

 -Ed


----------



## Edwood

Right after replacing the caps with Blackgates my first impression was "Where's the Bass?"

 Without the benefit of a stock DAC2 to compare to, I did at least feel that the bass was pretty weak compared to what I remembered. Particularly the lowest octaves with my R10's.

 Of course a couple hundred hours later, sounds like it's back! Woah. Not bass head levels, but that's because of my headphones.

 But it was so weird. I did not like how my R10's sounded like with these mods at first. The K1000's were great though. Some more sibliance was further removed. Mid bass was the main improvement sound frequency wise.

 But now, it's a different story. I'm liking my Bel Canto DAC2+ much much better with my R10's now.

 I still need to do an A/B comparison with a stock DAC2 though. I'm just too skeptical of the Placebo Effect.

 How many SoCal Head-fiers have a Bel Canto DAC2? 

 -Ed


----------



## 1UP

Does anyone know if it is possible to convert the DAC2 to use balanced outputs? 

 edit - sorry seen it now on page 7, nice


----------



## Jwinslow

Sorry to bring this up from the dead, but was curious if you had a chance to compare to a stock DAC2 and a Benchmark DAC1. I have both the Benchmark and the Bel Canto, and after reading this thread, I really got the itch to mod the Bel Canto.

 A few other questions- what value of caps did you use for the bypass on the FREDS? And did you ever do any further mods to the DAC?

 Also, your lack of gain when going balanced was probably due to lossing one stage of amplification.

 Thanks,

 Jason


----------



## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Sorry to bring this up from the dead, but was curious if you had a chance to compare to a stock DAC2 and a Benchmark DAC1. I have both the Benchmark and the Bel Canto, and after reading this thread, I really got the itch to mod the Bel Canto.

 A few other questions- what value of caps did you use for the bypass on the FREDS? And did you ever do any further mods to the DAC?

 Also, your lack of gain when going balanced was probably due to lossing one stage of amplification.

 Thanks,

 Jason_

 

They were quite close to each other with the balanced outputs from the DAC2+ as a reference. The unbalanced out is a little bit warmer. But the volume output loss with the balanced outputs on my DAC2+ makes it difficult to use where high gain is needed. i.e. I nearly have my Grace m902 maxed in volume with my K1000's.

 I found the bass to be a little bit more powerful with the DAC2+, and the treble decay to be a little bit more resolving on the Benchmark. The smooth quality of the Bel Canto is still there, but some of the previously slightly perceived muddiness is cleared up.

 Mainly the balanced output mod is the most effective as it really adds more versatility to this DAC, and is a little bit cleaner/clearer output than the unbalanced ones. I really don't know why Bel Canto did not include balanced outputs, there is clearly room for it, and it is in fact present in the circuit. (it just seems to be missing a small amplification stage.) It may have been a cost cutting measure, but the addition would not have added to the cost significantly. And it's not like they are trying to defeature it to not eat into sales of a higher end DAC, since they do not currently have one.

 -Ed


----------



## Jwinslow

Panasonic FC and FM caps, FREDs, bypass caps, Cardas solder, new soldering station all ordered and should be here by friday. Going to probably change the wiring harness from 22ga to 16ga or 18ga though it would probably not make one single difference.

 Only thing I need is a darned female board mounted BNC connector. I mean, come on, you would think some company out there would stock such a thing.

 This is going to be fun.


----------



## Edwood

The Bel Canto DAC2 uses Vampire PCB jacks.

 Use this one as a direct replacement
 :
 Part #PCBNC - PCB Mount Connector






http://vampirewire.com/mcart/index.c...3&page=2&cat=5

 -Ed


----------



## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Panasonic FC and FM caps, FREDs, bypass caps, Cardas solder, new soldering station all ordered and should be here by friday. Going to probably change the wiring harness from 22ga to 16ga or 18ga though it would probably not make one single difference.

 Only thing I need is a darned female board mounted BNC connector. I mean, come on, you would think some company out there would stock such a thing.

 This is going to be fun._

 

As for the wiring harness the best thing to do would be to remove the socket and plugs, and just solder directly into the board. But do this last, as it will make working on either board more difficult if you do this earlier.

 -Ed


----------



## Jwinslow

Thanks Ed. I must have been too sleep deprived when I was looking in the Digikey catalog...cause I finally found them today and ordered a couple- never know if I'm going to have an accident with one or two of them.

 The more I think about the wire harness, the more I really wonder exactly HOW much it would help, if any at all...one thing is for sure, it will make working on it a PITA if I ever had to take it all apart later on.


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Thanks Ed. I must have been too sleep deprived when I was looking in the Digikey catalog...cause I finally found them today and ordered a couple- never know if I'm going to have an accident with one or two of them.

 The more I think about the wire harness, the more I really wonder exactly HOW much it would help, if any at all...one thing is for sure, it will make working on it a PITA if I ever had to take it all apart later on._

 

Just use some more wire length, so that you have more slack so that you can separate the DAC board from the rear face plate. We're only talking a couple inches here, won't be a problem.

 -Ed


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## Jwinslow

Ed, was looking at the board and every cap has a + indication labeled on the board except for C69 down on the LED end of the board. Which way did you face that cap?

 Also, just curious if you had taken any kind of voltage readings on the balanced outputs you did? Roughly how many volts of output did you have since bypassing that last opamp section?

 Yeah, I think I'll end up making the harness...going through all of this trouble, might as well make the harness.


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Ed, was looking at the board and every cap has a + indication labeled on the board except for C69 down on the LED end of the board. Which way did you face that cap?

 Also, just curious if you had taken any kind of voltage readings on the balanced outputs you did? Roughly how many volts of output did you have since bypassing that last opamp section?

 Yeah, I think I'll end up making the harness...going through all of this trouble, might as well make the harness._

 

It is in the same orientation as the rest, take a look at this pic in this post.
http://www6.head-fi.org/forums/showp...&postcount=131

 I don't remember what the balanced outputs voltage reads were, I think I labelled them in a pic in this thread, go back a page of so, should be labeled there.

 -Ed


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## Jwinslow

Still not following...there is no indication on the board for that cap as to which one is positive.

 But it'll be tomorrow night or sunday before I get to her.


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Still not following...there is no indication on the board for that cap as to which one is positive.

 But it'll be tomorrow night or sunday before I get to her._

 

Have you removed the caps already? 

 Have a closer look at a pic here. It should be very very obvious which way the polarity is.

http://www6.head-fi.org/forums/showp...&postcount=138

 -Ed


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## Jwinslow

I think the near 100 degree 18 hour days had caught up to me...


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## Jwinslow

Just got finished with mine, plugged her up and turned on, but light stayed red.

 I did a whole slew of mods- from the BNC to bypassing the last stage of opamps by jumping from where Ed got balanced out and ran V+ and ground to the RCA terminals which I sut from the board and soldered to remaining leads.

 I wonder if that's where I messed up at?

 Anyways, long day of building and having a migrane at the same time...


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Just got finished with mine, plugged her up and turned on, but light stayed red.

 I did a whole slew of mods- from the BNC to bypassing the last stage of opamps by jumping from where Ed got balanced out and ran V+ and ground to the RCA terminals which I sut from the board and soldered to remaining leads.

 I wonder if that's where I messed up at?

 Anyways, long day of building and having a migrane at the same time..._

 

Did you make sure to press the front selector switch to the right of the SPDIF (BNC) input?

 I remember forgetting to do that a few times and wondering why it wasn't getting a signal lock, LOL.

 -Ed


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## Jwinslow

Yeah, I did that...wish it were only that.

 I'm thinking something happened when I soldered the 150 ohm resistor in parallel to the 150 on the board...so I could get a true 75 ohms at the termination point.


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## Jwinslow

Urh...only .3 volts output on the power supply when it's seperated from the board. Dunno what is wrong- I kept the cap orientation correct, have the FREDs positioned right, and have the bypass caps mounted on the bottom of the board.

 Geez.


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Yeah, I did that...wish it were only that.

 I'm thinking something happened when I soldered the 150 ohm resistor in parallel to the 150 on the board...so I could get a true 75 ohms at the termination point._

 

Have you tried the Toslink input, does that one work at all?

 Can you post pics of where you soldered the 150 ohm resistor, and any potential problem areas.

 -Ed


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Urh...only .3 volts output on the power supply when it's seperated from the board. Dunno what is wrong- I kept the cap orientation correct, have the FREDs positioned right, and have the bypass caps mounted on the bottom of the board.

 Geez. 
	

	
	
		
		

		
		
	


	


_

 

You did remember to discharge the caps BEFORE plugging the PSU board back into the DAC board, right?

 Again, post pics or link to some pics, we can help you better.
 It helps for you to label what voltages you are reading from specific areas, like I did a few pages back in this thread.

 0.3V is too low, obviously. Keep in mind that there are two main power sections in the PSU (note the two toroids and where the circuit goes, look underneath the board). One is for the Analog section of the DAC board, the other is for the Digital section.

 -Ed


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## Jwinslow

I sent her off to an Electrical Engineer buddy of mine in Atlanta today...had a trace on the board lift off, and he's going to fix that for me and double check my work. He is involved with cell phones by day and hot rodding audio equipment at night. I think I'm going to have him do the surface mount stuff in the Benchmark DAC1 I have.

 I'll keep everyone up dated.


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_I sent her off to an Electrical Engineer buddy of mine in Atlanta today...had a trace on the board lift off, and he's going to fix that for me and double check my work. He is involved with cell phones by day and hot rodding audio equipment at night. I think I'm going to have him do the surface mount stuff in the Benchmark DAC1 I have.

 I'll keep everyone up dated._

 


 Wuss. 

 Giving up so easily, eh? 
	

	
	
		
		

		
		
	


	




 Heheh, just kidding.

 -Ed


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## Jwinslow

Nah, I'd probably keep fixing it until it's broke for good...lol.


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Nah, I'd probably keep fixing it until it's broke for good...lol._

 

That's the spirit!

 If it ain't broke, BREAK IT!

 Uh, I mean, MOD IT!

 -Ed


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## Edwood

Finished a FPE file.







 Hoping FPE doesn't fuxor it up.

 -Ed


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## Edwood

Finally got the FPE part today.











 Aside from a few holes being too small, it fits perfectly.

 Will post a pic with it installed later. Since this panel is much thicker than the temporary one I made, I need to get a few longer screws since they no longer reach.

 -Ed


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## Edwood

-Ed


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## MisterX

Looks pretty good Ed.


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## Jwinslow

Now that is HOT.

 Ed, know if the RCAs work at the same time the balanced outs are connected?


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## Edwood

Quote:


  Originally Posted by *Jwinslow* 
_Now that is HOT.

 Ed, know if the RCAs work at the same time the balanced outs are connected?_

 

Yep, no problems, they both output simultaneously. The unbalanced stage gets amplified a bit, so the balanced output has less gain.

 -Ed


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## mustang

Wow that looks pretty. Great job Ed!


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## Bails

Well, having read this thread I sent my Bel Canto DAC2 off to have Black Gates and FREDs installed. I should get it back in a couple of days.

 I'm wondering what sort of a difference adding a Superclock would make. I know Edwood was originally planning it but I don't think he got around to it. Does anyone have a view on what sort of difference a new clock makes to dacs in general, or to the Bel Canto in particular?

 Thanks


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## chenzhengbin

Amazing job!


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