# The "Lovely Cube" Headphone Amp (Lehmann Black Cube Linear Clone)



## francisdemarte

Someone was kind enough to provide a link to this amp on ebay in the Matrix M-Stage thread. I thought I would be a great amp around 1/2 the price of the M-Stage and an easy DIY project to pass the time.
  
  


*EDIT 04/13/2011:* You can now buy the Lovely Cube Premium fully assembled.







 For details: http://www.alicemagicbox.com/lasercollection/lovelycubepremium.html




*Hardware*
  
  
 The "Lovely Cube" is sold on ebay by Laser Collection. It runs about $100 shipped for a fully populated board, a pair of nice quality RCA jacks, some heat shrink, a few SIP connectors for the inputs, and a couple of LED's.
  
 The vendor also sells the rest of the components you need to complete the amp: 220v transformer and case as well as unpopulated boards.
  
 The Lovely Cube is an exact copy of the Lehmann BCL where the Matrix M-Stage is a slightly altered version. Here's some pictures I borrowed from the ebay auction:
  
  
  

 Bottom of the board with the Gain adjustment DIP switches.
  
  

  
 Alps volume pot
  


 Swappable opamps. I switched the SOP + adapter for the DIP8 version of the OPA2134 I had laying around.
  
  

  

  
 The amp arrived via normal HK Post about 2 weeks after I ordered it. All components look to be name brand and high quality.
  
 Be aware that it came with no instructions of any sort, so you'll have to be a little familiar with DIY. In the picture above I've labeled all the wiring points for everyone's reference. 
  
 On the far left is the primary input, grounds in the center and signals are the outer connectors.
 The center 3 connection points output 15V DC. It is used in the USB version of the Lehmann BCL to power the DAC and USB ports. Pretty nice addition since you can use it with a voltage regulator to power a DIY DAC.
  
 Next to that is the 2nd inputs, I believe these are muted if you plug a headphone into the 2nd headphone jack. I did not connect this in my installation.
  
 Lastly the power input with convenient screw terminals. The amp has an internal PSU so all you need to provide is a 15V AC transformer.
  
 Here's a internal picture of a real Lehmann to get an idea of how things look wired up.
  
  

  
  
*Sound*
  
 Going to reserve this space for further impressions. My current install in a old external CD-Rom chassis powered by the DY-1 power supply that came with the Head Direct EF-5 amp set at 16V AC.
  
 I have a minor grounding issue since my case does not have a faceplate. I hear buzzing on my low Z phones when I touch the volume pot, I think I need to ground it to the case. I'll update this section once I get a new case or get this issue resolved.
  
 Edit 07/07/2010: Buzz is now gone. I had to ground the Alps pot to the star ground in my case. The amp is now totally silent with no music playing and the volume turned all the way up with my 42 Ohm ATH-W1000X's.
  
  
*Initial Impressions*
  
 I'm not the best amp reviewer here but the review of the Matrix M-Stage's sound signature all applies here. This is a fantastic amp for the price! Fast, dynamic, and works well with all my headphones.
  
 Currently I have mine set at gain 0 and it really brings my ATH-W1000X to life. The bass goes low and hits effortlessly and the mids, while still forward are smooth. The HD650 also sounds great at gain 0!
  
  
*Initial Conclusion*
  
 This is a steal at around $100 shipped for a finished board. If you have a little DIY experience or want to get your feet wet without the complexities of putting together an entire amp this is a great start!
  

*Mods*

 Thanks to JiggaD369 for compiling a list of mods mention in this thread!

http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/915#post_7966068
  
  
 I basically went through the entire thread about three times in order to condense all of the info. This is basically my first complete DIY modding project and mostly out of curiosity. It was painful but worth it IMO!

 Below are the mods with Newark/Farnell part numbers (otherwise noted):


 PSU:
 Replaced the two 4700uf caps with United KMH caps (16M6799).
 Replaced the ADJ caps with Sprague10uf tantalums (30C8841).
 Replaced the R2 resistors with zener diodes as per BlaBla method (18C6023).
 Replaced the regulators with Fairchild (58K8936/58K8937).
 Replaced the four transistor 470uf caps with Panasonic FC (80K8337).

 Signal Path:
 Bypassed input caps with 6N copper wire.
 Replaced the stock opamp with OPA2111KP.
 Replaced the two opamp supply caps with Silmic II's.
 Replaced the two small 0.022uf caps bypassing the Silmics with Philips (.027uf) Polystyrene caps. (Ebay)
 Replaced the output 10 ohm resistors with Allen Bradley 1W carbon resistors (Ebay).
 Replaced the 100pf caps with LCR Polystyrene caps (64K0006)
  
  
  
  
  
  
*Thread Highlights & Updates*
  
 Edit 07/07/2010: Upped the gain to 10, which gives the HD650's a bit more oomph while still leaving some headroom for the W1000X's. 
  
 Edit 08/31/2010: The ebay seller now as an official site for the Lovely Cube: http://www.alicemagicbox.com/lasercollection/lovelycube.html
  
 Edit 09/24/2010: Sunneebear creates the first balanced Lovely Cube Amp! http://www.head-fi.org/forum/thread/501046/first-impressions-lovely-cube-semi-diy-amp-lehmann-black-cube-linear-clone/75#post_6948982
  
 Edit 10/01/2010: Comparison between Lovely Cube and Matrix M-Stage with the HE-5: http://www.head-fi.org/forum/thread/501046/first-impressions-lovely-cube-semi-diy-amp-lehmann-black-cube-linear-clone/105#post_6964362
  
 Edit 10/13/2010: ebay seller now has OPA627AU and Class A adapters available. Nichicon KG Gold Tune 4700uF 50V replaces the Elna for Audio 4700uF 35V caps on new units. Some pictures by aspenx http://www.head-fi.org/forum/thread/501046/first-impressions-lovely-cube-semi-diy-amp-lehmann-black-cube-linear-clone/105#post_6990039
  
 Edit 11/14/2010: Removed output caps replaced with solid core wire, opens up sound stage a bit and increases treble extension. 
  
 Edit 11/29/2010: Is your Lovely Cube case feeling very warm? Relax, it's suppose to be that way: http://www.alicemagicbox.com/lasercollection/lovelycubesecretofheat.html
  
 Edit 01/16/2015: Corrected and updated schematics. Thanks Habibelhabab! http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/1170#post_11021088
  

  
  

  
  

  

*06/10/2016:*
  
 More technical discussion from diyaudio.com:
  
http://www.diyaudio.com/forums/headphone-systems/285380-headamp-upgrading-lehmann-bcl-clone.html 
  
  
 Some board were found with manufacturing defects that caused persistent hum. This thread offers a solution:
  
http://www.diyaudio.com/forums/headphone-systems/271057-100hz-hum-lehmann-linear-clone.html


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## francisdemarte

Some pictures of the board in my temporary enclosure. Forgive my poor photography, it was late.
   
   

   
  Wired up and powered up for the first time
   

   

   
  Encased in a old SCSI cd rom enclosure. Still have to fix the stand off screw .
   

   
  Powered up and stacked up. Laptop > Gamma2 DAC > Lovely Cube powered by Hifiman DY-1 (From EF5 amp)


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## prospero21

Looks very promising. As im in the market for a new headamp (my Zero died on me after 2 yrs of faithful service) and I might try going the DIY route, this would fit the bill nicely.
  I'll most certainly will keep an eye on this topic for the days to come.
   
  What would be good dac companion for this board ? http://cgi.ebay.com/MUSE-HIFI-USB-S-PDIF-Converter-USB-DAC-PCM2704-/120576181155?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item1c12e683a3 maybe ?


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## francisdemarte

Quote: 





prospero21 said:


> Looks very promising. As im in the market for a new headamp (my Zero died on me after 2 yrs of faithful service) and I might try going the DIY route, this would fit the bill nicely.
> I'll most certainly will keep an eye on this topic for the days to come.
> 
> What would be good dac companion for this board ? http://cgi.ebay.com/MUSE-HIFI-USB-S-PDIF-Converter-USB-DAC-PCM2704-/120576181155?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item1c12e683a3 maybe ?


 

 It's a nice basic DAC but probably won't be on par with your Zero.


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## reiserFS

Got a link to the seller's shop? Can't seem to find anything under "Lovely Cube". For under 100$, this might become my first DIY amp.
   
  Edit: Nvm, found it.


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## aspenx

Thanks for the writeup!
   
  Looking forward to more information on this lovely cube.


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## francisdemarte

Ebay auction is here:
   
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200482693027&ssPageName=STRK:MEWAX:IT#ht_11841wt_1101
   
  Seller is: Lasercollection
   
  PM him directly for lower prices or the cost of other parts.


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## francisdemarte

Pictures added! Next up will be comparison between the Lovely Cube, EF-5, and Aune (Graham Slee Solo clone).


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## aspenx

Wow. You're right.
   
  The quote for the metal case is very high. This is my first time with DIY and I'm wondering how I'm going to get a case for this...


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## francisdemarte

I used an old external CD-ROM case cost me nothing.
   
  Cheapest route is to recycle some old electronics. Ask your friends, go to your local junk shop, garage sale, or your neighbors trash and look for old audio video equipment. They are nice because they will already have a power jack and RCA plugs built in, all you have to do is rip the rest of the stuff out.
   
  Even cheaper you can use a cookie tin, wooden craft box or even a cardboard box. Just have to watch that it doesn't catch fire 
   
  Or else theres the pricier DIY route. Find a vendor that sells cases and ships to your country. 
   
  Like this one:
http://www.diyfidelity.com.au/index.php?cPath=36&osCsid=4136e1b146c69d0a36722e803f5d5c3d


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## aspenx

Does that mean the RCA jacks are not provided in the "package"?
   
  Will I be correct to say that in addition to the board, I'll be needing a case, RCA jacks, power jack, a transformer (which I think I can get for $10 locally), some form of knob for the potentiometer and some jumpers?
   
  Yes, I've seen CMOY amps in Altoid cans (only online though). Very amusing...
   
  But something wooden and cherry wood like will be nice to match the W1000X.


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## SpudHarris

Looks great........
   
  I've asked him about the enclosure, I'm assuming it's expensive?


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## aspenx

I was quoted 30 GBP. Might not be expensive to most (?) people here.
  More details on the case:
   
  Quote: 





> [size=10pt]1) 6mm thick aluminum front panel
> 2) 2mm thick metal body
> 3) 2 ready holes on the bottom for 2 dB switch
> 4) IEC fused socket included
> 5) 30 mm Dia Full aluminum knob included[/size]


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## francisdemarte

It's $57 shipped, no too bad considering it has a pre-drilled front plate, but the added cost put you very close to a finished M-Stage.
   
  Here's what I was quoted.
   
  1) Finished Board : US$93  (if outside ebay, rebate all ebay charge : discount US$7 , i.e. US$86)
  2) Shipping of above board :  US$14
  3) Metal case : US$42
  4) Combined shipping (HK-USA) for Metal case : US$15
   
  Total amount for outside ebay : US$86 + 14 + 42 + 15 = US$157
   
  You'd still need a transformer that outputs 15V 1Amp transformer You can get one for around $30 from mouser/digi-key/farnell/parts-express etc.
   
  Assuming you have wires, soldering iron, wire stripper etc. your looking at about $200.
   
  Might I suggest someone put together a *group buy*! I would do it but I have a wedding in 1.4 months.


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## aspenx

Deleted post cause I realised I wasn't making any sense.


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## reiserFS

I might fit this baby inside a Hifi2000 Slim case, probably going to look sleek.


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## InFn-0

this might be a very stupid question, but does the seller provide the on/off button near power in thing? or will i have to source it from elsewhere? Im talking about the one in the picture below


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## francisdemarte

No, but I believe that comes with the case which I did not order. The board itself came with a pair of really nice quality RCA jacks.
   
  That thing is called and "IEC power jack", this particular one has a fuse and a power button built in. You can order them online or just rip them out of some old piece of electronics equipment.
   
  New pictures, I've decided the case I was using was too big and heavy. re-cased it in a $5 project box from Radio Shack. Now I have shorter cable runs with silver teflon cables.
   

   

   
  The brass knob is from Head Fi'er Vilts.


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## francisdemarte

Stumbled on more technical info for the Lovely Cube.
   

   

   

   
   
  BOM:
   
   
 The Kit Parts List :
 [size=medium]
 *Parts* *Parts no. on PCB (not on Schematic)* *Qty*       Resistor *VISHAY DALE*   100R 1/4W R305、307、314 8 10K 1/4W R101、201 5 15K 1/4W R313 3 1K1 1/4W R306、308 6 1K5 1/4W R106、108、206、208 10 2K2 1/4W R103、204 5 3R3 1/4W R301-304 10 47R 1/4W R105、107、109、205、207、209 15 4K7 1/4W R102、202、311、312 10 680R 1/4W R104、203 5 10R 1W R110、111、210、211 (Panasonic / Taiwan Resistor) * note 1 10 47R 1W R309、310、315、316 (R309 & 310 : 3W OHMITE -USA / DRALORIC) * note 1 10       Capacitor     250V/1.5u C101、201 (Simens) * note 1 2 63V/0.022 C102、202、315、316 (SPRAGUE 223 / ERO 223) * note 1 4 250V/0.1u C301-304 (BC / ERO) * note 1 4 63V/0.15u/154 C307-312 (Simens / ERO) * note 1 6 63V/100P C317、318 (Philips Tin Foil) * note 1 2 63V/102/1n/1000P  C319 1 35V/470uf  C103、104、203、204、313、314 (Philips BC / ELNA RE3 25V) * note 1 6 50V/4700uf C305、306 (ELNA) * note 1 2   * note 1 : Brand /Model depends on stock availability , or same grade         Transistor / Diode     BC560（TO-92） Q101、201 2 BC550（TO-92） Q102、202 2 BD140（TO126） Q103、203 2 BD139（TO126） Q104、204 2 LM317（TO-220） Q301 1 LM337（TO-220） Q302 1 BYV27-200 (Diode) D301-304 4 LED L301、302 3mm 2 LED L303 (Blue) 3mm 1       IC / OPAMP     OPA2134UA  SOIC to DIP8 1       Others     2 Way dB Switch/Selector SW101、201 2 Fuse (PPTC) 72V 0.9A F201、202 2 PCB Gold Plate 1 Heat Sink TO-220  Large for Rectifier /Small for BD139/140 6 TO-220 Silica Set Sheet+Plastic Ring+Screw 6 6.35mm Headphone Jack  NEUTRIK 2 5.0mm Connection Block 3PIN for AC Input 1 VR 50K*2  ALPS-27 (Half Round Shaft) 1 DIP-8P Socket Nextron 1 RCA Socket One Red, One Black 2 Transformer ( Optional) Input : 220V (Red - Red)   Output : 2x15V 30VA (Blue - Blue , Black - Black) Optional      
  
[/size]


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## kboe

Sweet option for the money, not to mention the ability to put it in any case one desires!


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## purrin

francisdemarte: Have you direct-coupled the inputs yet (removed caps)? Also do you think you will replace the diodes D301-D304 with HEXFREDs or other soft-recovery diodes?


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## francisdemarte

Quote: 





purrin said:


> francisdemarte: Have you direct-coupled the inputs yet (removed caps)? Also do you think you will replace the diodes D301-D304 with HEXFREDs or other soft-recovery diodes?


 

 Nope haven't done it yet. I'm leaving for vacation and my wedding Thursday and I'll get to it when I get back.
   
  I've always been dissuaded from using high speed soft recovery diodes/FREDs/Schottkys as I've been told they make very little to no audible difference over a traditional one. Do you have any experiences to the contrary?
   
  The next major mod I think I'll make is to replace the RK27 with a DACT or the Twisted Pear Joshua Tree  attenuator and a nicer wood case  over the $7 Rat Shack one I'm using now.


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## aspenx

After much consideration, I've finally placed an order over the weekend.
   
  I have no DIY experience at all so I'm hoping it wouldn't be too tough.
   
  Should I be looking for RCA jacks, some jumpers (if so, what types?) and a power cord now?
   
  I got the whole package with a nice-looking Talema transformer by the way.


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## francisdemarte

You'll do fine, just take your time.
   
  I recommend you start a thread on the DIY forum. If you get stuck you can ask for help there or in this thread.
   
  Post lots of pictures!


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## DaEMoNteNTAcLe

i believe he provides the RCA jacks as well..


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## aspenx

Alright. I'll make a thread if I do need more help with the DIY.
   
  I'm getting fidgety already (it's still not here!) and had forgotten that it's supposed to come with the jacks. While waiting, I did realise that the old iron is busted, the only solder I could find at home is too thick and a lot of equipment that I thought I had are missing. Going to have to do more shopping.
   
  Hmm, I'll be sure to post pics alright. Heh. What with nobody else doing so. We need more pics and feedback!
   
  And oh, congratulations on your wedding Francis!


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## francisdemarte

They send by regular post so it took a week and a half for mine to arrive and clear US customs.
   
  You'll need:
   
  * basic soldering iron and if you feel like it accessories like a stand and a sponge (I like Weller)
  * Electrical grade solder
  * Flux (I like the paste type that comes in a tube or jar, and a toothpick to spread it)
  * 22-26 gauge wires of your choice 
  * A nice pair of wire strippers that can handle small 22-26 gauge wire
  * small screwdrivers 
  * heat shrink tubing (They provide a couple of pieces in your order but its nice to have extra of various sizes)
  * lighter to small torch for the heat shrink tubes
   
  Not necessary for this project but nice to have is a digital multimeter if you want to do more DIY projects in the future. 
   
  Tanget has some nice video tutorials on soldering: http://www.tangentsoft.com/elec/movies/
   
  PS: Thanks for the wedding wishes  I take off for Costa Rica tomorrow! 
  PPS: Really nice to see all the Audio Technica woodie fans.


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## aspenx

Stephen, the seller, says it should take 4-6 days to reach me (Singapore) after he mails it later today. 
	

	
	
		
		

		
			




   
  Thanks for the comprehensive list! Do you think I should get wires too while I'm at it? How about a "3rd helping hand"? I came across tangent's site after following a link on the STEPS regulator here and I've been glued to it ever since (the "luxury" of unemployment). Great material and I'm already thinking of assembling the YJPS out of curiousity. haha
   
  Have a great wedding and come back to enjoy your AT woodies soon!


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## aspenx

Okay. It arrived on Monday. Very nicely packaged and bubble wrapped.
   
  After practising my soldering first, blowing a fuse (a spare one was provided! phew) and fumbling around, I managed to get it up and running with the seller's patient assistance through email.
   
  I read that the BCL sounds best at the highest gain setting, so I'm using that with W1000X. The headamp is basically noise-free for my listening and pretty transparent in my opinion. I'm actually sad that my source (Musiland Monitor 02 USD) is not that fabulous. Regardless, soundstage and bass are noticeably much better.
   
  It really brought a old CD player that I dug up back to life though. And here it is, the full package with the top removed:
   

   
  I noticed that there isn't a clear image of the opamp used in the output stage so...

   
  It's a BBOPA 2134UA. Burr Brown?
   
  Anyways, it was a great first experience with DIY. Seller provided basically everything to complete the amp. Very good workmanship, parts and service for the price point, in my newbie opinion.


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## komebudu

Aspenx,
   
  Very nice photos....  nice job.


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## francisdemarte

Great job! Glad to see you got it all up and running!


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## aspenx

Thanks kmoebudu for the compliment!
   
  Francis: Thanks! I'm lucky it wasn't as difficult as I thought it'd be... And welcome back. I hope you had a great wedding.
   
  Now, please let us know what you'd be modding soon. Do you think a YJPS or TREAD will really improve this? Will you still be proceeding with replacing the pot with the Joshua Tree? How about direct-coupling the inputs? Have you tried opamp-rolling with it yet?
   
  Sorry for all the questions. I blame the DIY bug. Which reminds me that I'm itching to build a DAC for this Lovely Cube.


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## DaEMoNteNTAcLe

i've just got my unit last friday,...
  after some extensive listening,
  i conclude that this amp is quite a value for its price,
  it is able to push my can (profile pic) very high.. not many headamps i've tried (maverick D1, hifiman EF5, crossroad Amp, Linearossa K3, etc) is able to do so.
  lasercollection was also prompt in replying my email and questions.
  since my order got delayed for about 10days coz of the talema toroid, he actually provided some extras along with the amp as compensation. very nice seller.
   
  the bottom line, i got my cans to a level im quite happy with.. now i can sleep


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## Bullseye

Anyone performed any RMAA on this amp? Looks quite good for the price!


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## sunneebear

I bought a pair with the intention of trying them balanced.  I just tried one out on the table top without any chassis.  I am quite surprised that there is no interference noise without a chassis to shield.  Also at max gain it is dead quiet.  I am using transformers from the same seller for power.  Running itunes to a Matrix Mini-i DAC and driving a SA5000.
   
  Have to agree that it sounds pretty sweet for $100.  Being a Lehmann linear clone, I guess it should sound good.  Not bad for fresh out of the box, workbench wired and no warm up or burn in.  All I have to do now is look for a case of some sort.


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## aspenx

Don't know if you guys are aware, but the seller made a webpage for the Lovely Cube:
   
http://www.alicemagicbox.com/lasercollection/lovelycube.html


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## purrin

Quote: 





sunneebear said:


> I bought a pair with the intention of trying them balanced...


 

 That's awesome - was thinking the same thing.


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## InFn-0

Anybody tried comparing this to the actual black cube linear or the m stage??


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## francisdemarte

Quote: 





purrin said:


> That's awesome - was thinking the same thing.


 

 x3 Same here! Race may be on to see who has the first balanced Lovely Cube...or should I say Lovely Cube^2


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## francisdemarte

Quote: 





aspenx said:


> Don't know if you guys are aware, but the seller made a webpage for the Lovely Cube:
> 
> http://www.alicemagicbox.com/lasercollection/lovelycube.html


 

 Thanks for the link! I've added it to the first post for everyone's reference.


  
  Quote: 





aspenx said:


> Thanks kmoebudu for the compliment!
> 
> Francis: Thanks! I'm lucky it wasn't as difficult as I thought it'd be... And welcome back. I hope you had a great wedding.
> 
> ...


 
   
  Thank you for the wedding wishes! I actually just got back from Costa Rica yesterday, the wedding and Honeymoon was quite an adventure!
   
  To answer your questions. With the amp being near silent as it is, I don't believe a better power supply will have a good cost/benefit. You'll probably need something much better than a simple Tangent THREAD, your definitely looking at either the YJPS or AMB's sigma 22 to improve on the on board.
   
  The wedding/honeymoon pretty much blew my budget for head fi for a while. I was going to try some opamp rolling (maybe pick up the OPA627 or Burson discrete op amp) and do the Class A biasing as detailed on headfonia.com and in the M-Stage thread. The next major mod would be to purchase another Lovely Cube board and create a balanced version of the amp for my HD650's.


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## DaEMoNteNTAcLe

haha..
  very proud i got my amp in the links..
  that one from malaysia is mine. 
   
  anyways, contrary to reviews, i found this amp to be quite neutral.
  btw, anyone modded or swapped op-amp on this one?


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## ninjikiran

Although I would say an alluminum or similar metal enclosure would be best you can buy one of those plastic food containers and easily cut a few holes into that for volume knob and the such.  Best yet you can take your amp to work with a cheese sammich on top of it.
   
  http://www.traderscity.com/board/products-1/offers-to-sell-and-export-1/plastic-take-away-food-container-900ml-rectangle-70399/
   
  Heck add an extra layer and you can cannibalize a dac and solder the output directly to your DIY amp eliminating the need for long external cables


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## sunneebear

Was at a liquor store today and saw that Ty-Ku white comes in a decent looking bamboo box with laser etched designs on the sides.  Could be a nice enclosure.  Might have to get drunk one weekend.


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## ninjikiran

Quote: 





sunneebear said:


> Was at a liquor store today and saw that Ty-Ku white comes in a decent looking bamboo box with laser etched designs on the sides.  Could be a nice enclosure.  Might have to get drunk one weekend.


 

 Don't know the properties of bamboo but might be a bit of a fire hazard in a worst case scenario.


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## aspenx

Quote: 





daemontentacle said:


> haha..
> very proud i got my amp in the links..
> that one from malaysia is mine.
> 
> ...


 
  Burning in with LT1364 now and 2 DIP sockets for fast class A biasing on standby.
   
  Oversized input bypass and decoupling .022uF caps just because I had to make up the sum to get free delivery.
   
  I don't know if transistor "rolling" because I shorted them accidentally counts though. ><
   
  EDIT: I just checked the M-Stage thread and purrin has done the multiple DIP socket for biasing thing first and has pics for it! My MM02 DAC has only 0.2mV of DC offset on both channels so I might try direct coupling sometime later too, but right now LT1364 is sounder MUCH better for the main kinda songs I listen to.


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## aspenx

Quote: 





francisdemarte said:


> Thank you for the wedding wishes! I actually just got back from Costa Rica yesterday, the wedding and Honeymoon was quite an adventure!
> 
> To answer your questions. With the amp being near silent as it is, I don't believe a better power supply will have a good cost/benefit. You'll probably need something much better than a simple Tangent THREAD, your definitely looking at either the YJPS or AMB's sigma 22 to improve on the on board.
> 
> The wedding/honeymoon pretty much blew my budget for head fi for a while. I was going to try some opamp rolling (maybe pick up the OPA627 or Burson discrete op amp) and do the Class A biasing as detailed on headfonia.com and in the M-Stage thread. The next major mod would be to purchase another Lovely Cube board and create a balanced version of the amp for my HD650's.


 
  Yea, I'm thinking of building the sigma22 but am really too bummed out and I really should be concentrating more on "real life issues". haha.
   
  If you're interested in the 627, Stephen (lasercollection) actually carries it: http://cgi.ebay.com/2-pcs-Dual-BB-OPA627-SOIC-DIP-Adaptor-/190433490176?pt=LH_DefaultDomain_0&hash=item2c56b87500 . It won't do your wallet that much of a damage and you get 2 of them, one for each Lovely Cube!


----------



## stau

Hi
 Question

 It is replaceable by hand?

 Original OPA2134 out

  and put the OPA227?

 yes?

 Thank you
   
   
   
  @aspenx
   
  thanks


----------



## aspenx

Yes, just replace the chip.


----------



## francisdemarte

Well yes and no. The OPA227 is a single channel chip, so you'll need 2 on an adapter. Are you sure you don't mean the OPA2227 which is a dual channel?
   
  Also look up the chip's max voltage on the manufacturer's datasheets. I think (althought I'm not sure) the Lovely Cube supplies 15V to the opamp. This should work with most chips, but its safer to check first.


----------



## aspenx

Oops. I misread.
   
  And yes, the Lovely Cube is designed to run at 15V for V+ and V-. Mine clocks in at 14.84V.
   
  The OPA227 will work with 15V supply but 2 of them will have to be mounted on an adapter (2x SOIC8 OPA227 on something like the "Brown Dog") to work for both right and left channels. If you don't already have the OPA227, the OPA2227 will be the easiest solution (http://sg.farnell.com/texas-instruments/opa2277p/op-amp-dual-precision-pdip8/dp/1459562) that you can directly replace the OPA2134 with.
   
  "DIP8" and "No. of Amplifiers:2" are the 2 main keywords to look out for. "Max Supply Voltage:18V" means that the 15V supplied by the Lovely Cube will work (http://focus.ti.com/lit/ds/symlink/opa2277.pdf).


----------



## stau

I ordered lovely cube  
 I'll write more later


----------



## francisdemarte

Awesome  Welcome to our exclusive club!


----------



## Cya|\|

How much for the assembled final version, plus shipping to europe?


----------



## francisdemarte

This is a DIY project and I don't believe there is a fully assembled version. You can try contacting the vendor on ebay.
  Otherwise if you need something completely built I would go with the Matrix M-Stage.


----------



## Cya|\|

On his site he said he assembled it for one of his customers. The price is quite low, maybe dac+this is a better alternative to the audio gd fun.


----------



## aspenx

It doesn't take much to hook it up but if the seller does offer an assembled headamp at this pricepoint, it'll really be a close competitor to the M-Stage.


----------



## Cya|\|

So, i'm still evaluating if to get this or the audio gd fun, for the same price (can't really spend more than a fun A version). I will get information about the m stage too, but in the meanwhile, here some questions:
  How does it work with low impedance cans?
  So this sound exactly like the 1000$ original black linear cube?
  What's the difference between m stage? This one also seems to have better components.


----------



## aspenx

1. I'm using it with the W1000X and I don't have much complaints because my DAC isn't exactly great. I can't tell if the qualms I have are with the amp or the DAC, but it was definitely quite a big upgrade from using the built-in amp on my DAC.
   
  2. The last time I heard the original BCL was thru a Marantz SACD player hooked up probably with some hi-end cables and power filtering etc while lying back on the leather recliner in dynaaudio5555 in Akihabara. I don't have any of that at home and as unreliable as acoustic memory goes, listening to the same CD (but FLAC-ripped and played through my computer setup instead) the Lovely Cube stock sounded a bit more congested. I've rolled to a LT1364 biased to class A and made some changes to the input and decoupling caps. It sounds more open now for a slight tradeoff in the bass impact.
   
  3. I think better components too.


----------



## BobbyGeneric

I'm guessing this amp isn't the exact sonic equal to the lehmann black cube linear but at about 1/5th the cost (for a fully built amp, including shipping), I ordered one. Looking forward to receiving it and providing my impressions.
   
  I ordered the fully built amp and he also is doing the class A biasing for me. I'm just hoping it's a decent step up from the years old PPA I've been using to drive my HD650's and ATH-A2000X


----------



## Cya|\|

With class A biasing, u mean that he's adjusting the bias?


----------



## BobbyGeneric

Quote: 





cya|\| said:


> With class A biasing, u mean that he's adjusting the bias?


 

 Here's the quote from the seller (note I also got the OPA627 from him):


> [size=10pt]I am now making sockets for Class A Bias (3mA & 5mA) .  If you have interest in this Class A Bias with OPA627 , I can give this socket Free of Charge when you buy OPA 627 together.  The method and MOD process will be updated in webpage within a week.
> [/size]


----------



## Cya|\|

He just answered me and said that audio gd earth opamp won't fit in, even with extension cable.
  What other opamps do you suggest? opa627 may be too warm for the audeze lcd-2. What about a LT1028?


----------



## francisdemarte

Quote: 





cya|\| said:


> So, i'm still evaluating if to get this or the audio gd fun, for the same price (can't really spend more than a fun A version). I will get information about the m stage too, but in the meanwhile, here some questions:
> How does it work with low impedance cans?
> So this sound exactly like the 1000$ original black linear cube?
> What's the difference between m stage? This one also seems to have better components.


 

 It works great with low impedance cans due to the fact that the gain is adjustable. I have mine set on 10 and I find that this works with my low impedance W1000x as well as my high impedance HD650's. 
   
  I don't believe very many people have heard both the Lehmann and this amp side by side so it's hard to say. Closest review I can find is on headfonia.com where the Lehmann and the M-Stage are both reviewed. They sound a little different due to the choice of components. All 3 amps use high quality components but since they are different components they will sound slightly different.
   
  While the Lovely Cube is an exact clone of the Lehmann Black Cube's circuit board the M-Stage is slightly modified version of it. Biggest difference is that the M-Stage has 2 switchable RCA inputs and one headphone out, the Lehmann and the Lovely Cube has 2 headphone outs. The majority of the circuit is identical amongst the three amps. 
   
  Between the M-Stage and the Lovely Cube I suggest if your not planning to do major modding and tinkering with the components get the M-Stage. The Lovely Cube is geared more toward people who want to do DIY mods.


----------



## francisdemarte

Quote: 





cya|\| said:


> He just answered me and said that audio gd earth opamp won't fit in, even with extension cable.
> What other opamps do you suggest? opa627 may be too warm for the audeze lcd-2. What about a LT1028?


 
   
  Try the OPA827 or even try the OPA627. If you don't like it you can easily sell them. 
   
  Just try the amp with the included op amp first. Op amps are relatively cheap and easy to swap.


----------



## ninjikiran

The general design looks the same, I would say the largest difference is parts.  Taking the design and hand picking parts~  I decided to get the M-Stage because I really don't have the experience or real will to make my own.  At the same time it is a solidly constructed amp and I have no real issue with it.  Probably the only thing I would really like to DIY one day is one of those spiffy gamma dacs with a good USB component.  Even with that most of the later dacs are coming with solid USB components/Jitter removal.
   
  According to the M-Stage review page, this design does and can sound like it.  From personal experience I couldn't tell you.
  Quote: 





cya|\| said:


> So, i'm still evaluating if to get this or the audio gd fun, for the same price (can't really spend more than a fun A version). I will get information about the m stage too, but in the meanwhile, here some questions:
> How does it work with low impedance cans?
> So this sound exactly like the 1000$ original black linear cube?
> What's the difference between m stage? This one also seems to have better components.


----------



## aspenx

Quote: 





cya|\| said:


> He just answered me and said that audio gd earth opamp won't fit in, even with extension cable.
> What other opamps do you suggest? opa627 may be too warm for the audeze lcd-2. What about a LT1028?


 

 My LT1028s are on their way. If it means anything at all, the similar LT1364 I'm using now with the Lovely Cube is less warm than the stock 2134. Also, in the Matrix M-Stage thread, they managed to place the Audio-Gd HDAM to lie in the same space with the RCA hookup wires. From what I see, it looks very possible.


----------



## francisdemarte

Looking at the pictures from the official website I think it maybe because they mount the transformer in the middle of the case. You can probably squeeze it in if the transformer was mounted closer to one side.


----------



## Cya|\|

I'm very impressed by the seller. He replied to my emails very fast, and here is his new answer:
   

 *Hi,*
   
*Yesterday I said there is no room to fit the earth opamp , but  today after  I made real measurement , I find it is possible to fit it.*
   
*I know there has some discussion in the forum , so I have updated my website to give clearer image for MOD. : http://www.alicemagicbox.com/lasercollection/lovelycube.html#8*
   
*But I am sorry I cannot do this for you because the effect of this MOD is unknown , e.g. whether it is better than ic  opamp , or is the sound your favorite , or any noise / hum would cause.*
   
*Thanks and Regards*
   
*Stephen*

   
  I was feeling a little disappointed that no discrete opamp could fit in, but if they can, this may be my amp for several years. I'm quite probably gonna buy this. I'll try to pay it within the 30th of september, so i get free full assemblage.
  Do you guys think the cheap stepped attenuator he sells would be a big AUDIBLE improvement over the alps27?


----------



## aspenx

Wow. Free assembly. I wouldn't have taken the trouble to do mine alone if I had known...
   
  About the stepped attenuator maybe you can try asking Stephen or just try it out and let us know?
   
  I'm also wondering how you guys will do this step: "relocate the two caps (red circle) towards potentiometer". Do we use longer leads?


----------



## livewire

aspenx, that's a cool avi. Who is she? The gal from 2NE1? Sorry for the threadjack.


----------



## aspenx

Quote: 





livewire said:


> aspenx, that's a cool avi. Who is she? The gal from 2NE1? Sorry for the threadjack.


 


 Minzy, the maknae of 2NE1. Shamelessly ripped from their new Can't Nobody music video cos she's so badass. The style with the doberman is really cool too but I decided that this image was more creative.
   
  Are you a 2NE1 fan too? Their new album sounds absolutely fantastic!


----------



## francisdemarte

Quote: 





aspenx said:


> Wow. Free assembly. I wouldn't have taken the trouble to do mine alone if I had known...
> 
> About the stepped attenuator maybe you can try asking Stephen or just try it out and let us know?
> 
> I'm also wondering how you guys will do this step: "relocate the two caps (red circle) towards potentiometer". Do we use longer leads?


 
   
  You'll need to remove the ones currently on the board, buy two new caps and bend the longer leads at an angle and solder them in.


----------



## livewire

Quote: 





aspenx said:


> Minzy, the maknae of 2NE1. Shamelessly ripped from their new Can't Nobody music video cos she's so badass. The style with the doberman is really cool too but I decided that this image was more creative.
> 
> Are you a 2NE1 fan too? Their new album sounds absolutely fantastic!


 

 Thanks for the reply. I thought so! Those eyes!.....
  Am I a fan? I am now! I have heard of and seen pics of 2NE1.
  Havent heard their music, I will soon.


----------



## sunneebear

Finally got some time to put the pair of amps together.  Only a mock-up to set the layout for the case.  I am running it with a pair of LM4562 in class A (Purrin
	

	
	
		
		

		
		
	


	




).  This thing sounds sweet.  Balance and SE.  All I have to do now is disassemble it and put the finally touches on the case and maybe some cosmetic work.  Thing is, it sounds so good I can't stop listening.  Next weekend I guess.


----------



## dlaloum

Very cool - where does one look up how to make a balanced amp?


----------



## purrin

Quote: 





sunneebear said:


> Finally got some time to put the pair of amps together.  Only a mock-up to set the layout for the case.  I am running it with a pair of LM4562 in class A (Purrin
> 
> 
> 
> ...


 

 That is freaking-licious-awesome!!!  What DAC are you using?


----------



## purrin

[size=medium]
 Quote: 





dlaloum said:


> Very cool - where does one look up how to make a balanced amp?




​[/size]


  You will need a balanced DAC. Get two amp boards. Feed DAC outputs L+ and L- into L and R channels on amp #1. Feed DAC outputs R+ and R- on L and R channels of amp #2. Instead of L, R, Ground on headphones, you wire L and R channel of amp #1 into Left headphone driver, and L and R channel of amp #2 into Right headphone driver.  You just leave ground unused.


----------



## francisdemarte

Quote: 





sunneebear said:


> Finally got some time to put the pair of amps together.  Only a mock-up to set the layout for the case.  I am running it with a pair of LM4562 in class A (Purrin
> 
> 
> 
> ...


 

 Beat me too it! 
	

	
	
		
		

		
		
	


	




 Looking forward to some pictures!


----------



## sunneebear

Quote: 





purrin said:


> That is freaking-licious-awesome!!!  What DAC are you using?


 

 Matrix Mini-i.
   
  I have a set of Burson opamps that is currently split up in halves and used in other DIY projects.  Guess I will be soldering it back together while I enjoy the music.


----------



## sunneebear

Quote: 





francisdemarte said:


> Beat me too it!
> 
> 
> 
> ...


----------



## francisdemarte

Awesome build! What are you using for the volume control?


----------



## sunneebear

The original pots driven in sequence by a geared counter shaft.


----------



## sunneebear

Just put the old Burson opamps back together and plugged them in.  Headroom, detail, extension and all ooohh sooo smooothhh.


----------



## Cya|\|

Quote: 





sunneebear said:


> Just put the old Burson opamps back together and plugged them in.  Headroom, detail, extension and all ooohh sooo smooothhh.


 

 What ic opamp were u using?


----------



## sunneebear

LM4562 in class A as suggested by purrin.


----------



## francisdemarte

Quote: 





sunneebear said:


> The original pots driven in sequence by a geared counter shaft.


 

 That's a ingenious solution and a great alternative to a pricey 4 gang pot. Did you make that or did you buy it where?


----------



## purrin

Quote: 





sunneebear said:


> The original pots driven in sequence by a geared counter shaft.


 
   
  /emote worship
   
  You are a mastermind!


----------



## sunneebear

Thanks for the kind praise guys but I'm pretty sure I'm not the first to do this.   The idea came to me out of necessity.  When I first started DIYing, I could only afford used or surplus parts.  I found two mono Noble pots for dirt cheap and came up with this idea to use them.


----------



## dlaloum

Necessity is the mother of invention
   
  The pots are brilliant!


----------



## sunneebear

Finally put the finishing touches on my balance Lovely Cube.  It's a cheap case but hey it works.
   



   
  The completed layout.  Sorry for the blurry phone pictures.
   



   
  I am running it with the Burson dual op amps.  I also put larger heat sinks in the two transistors in front of the two large capacitors because they get pretty hot.  Is this normal for this amp?  Even with the large heat sinks the case gets pretty hot when I put the cover on.  I will be putting holes or a grill of some sort on the cover when I get a chance.  I am pretty sure that the amount of heat generated is acceptable but I don't like hot amps so I will try to remedy this issue.
   



   
  Anyone with this amp or the M-Stage think it runs kind of hot?


----------



## sunneebear

Quick comparison with the Little Dot MK VII+. 
   
  At about $100 cheaper than the LD with shipping (complete cost of my build), the option of op amp rolling is what makes this amp so great.  Not just the cost.  With the two ICs, stock and the LM4562, this amp's sound quality is very close to the LD.  When biasing the LM4562 into class A, the Balance Lovely Cube "BLC" I think is quite equal to the LD.  There is some give and take.  Little differences between the two but I am very happy with either one.  With this quick comparison I won't be getting into the specifics of the sound but I can say that either one of these amps is easily worth more than what they cost.
   
  Running the BLC with the Burson dual op amps will put it's cost close the the LD but the sound is better.  It may not be apparent at first listen but then you begin to pick up things like better micro detail, sound stage, headroom, separation and placement.  From  what I'm hearing, the LD might end up on the for sale forum.


----------



## dlaloum

Quote: 





sunneebear said:


> Anyone with this amp or the M-Stage think it runs kind of hot?


 

 I agree - received my M-Stage early in the week, and have been doing burn in and preliminary listens...
   
  It definitely runs very warm - the buffer stage is a nice and toasty class A clearly!
   
  I have yet to fit Purrin's class A mod - and I have a collection of opamps to try out.... would love to bias them further into class A than the initial adapter (provided very handily by JTAM along with the M-Stage) - but I can now see why he was being conservative, given the warmth of the sealed case without the class A mod.
   
  I have spare heatsinks and such lying around - but given a sealed case, already running warm - benefit is likely to be limited
   
  I will be looking on to see what your cooling solution looks like - and am thinking about how to let air in and out of the M-Stage case without destructive alterations


----------



## francisdemarte

Quote: 





sunneebear said:


> Finally put the finishing touches on my balance Lovely Cube.  It's a cheap case but hey it works.


 
   
  Where did you get the case? Looks like the perfect size for my planned balanced LC and Opus DAC.
   
  My Lovely Cube doesn't get very hot at all, and it's running off the 18V AC power supply from my EF5 driving a pair of 300ohm HD650's...


----------



## sunneebear

Quote: 





francisdemarte said:


> Where did you get the case? Looks like the perfect size for my planned balanced LC and Opus DAC.
> 
> My Lovely Cube doesn't get very hot at all, and it's running off the 18V AC power supply from my EF5 driving a pair of 300ohm HD650's...


 
  http://www.customaluminumboxes.com/  Really great company to deal with.  Yes my case is custom made.  You select the type, size, thickness and some other things and you get a quote.  Mine only cost $32 shipped.  Much much better than those cheap project boxes that are quite expensive.  I chose the medium thickness option and it's very sturdy, no flex at all.  I may try the thickest option if I order again.  The face plate is a 3/8 acrylic scrap I had lying around.
   
  Could it the Burson op amps that's making it hot.  Let me try the stock ones tonight.


----------



## sunneebear

Quote: 





dlaloum said:


> I will be looking on to see what your cooling solution looks like - and am thinking about how to let air in and out of the M-Stage case without destructive alterations


 

 One option is to put holes in like http://www.head-fi.org/forum/thread/513379/diy-charity-raffle-twisted-pear-ventus but larger holes.  The other is to cut out the whole area and attach a grill of some sort inside.


----------



## sunneebear

I ran the stock IC and the LM4562 for about an hour.  The amp runs just as hot with them as the Burson.


----------



## Cya|\|

Anyone tried the bias mod? Wich one do you think is the best?


----------



## dlaloum

Lookup purrin's posts....
   
  I have the mod ready to go but am currently listening stock to get to know the base sound before I go changing it!


----------



## Cya|\|

I cannot find it.
  But is the 3.49 bias better than default? If so should i go for it to have a balance between performance/safety?


----------



## aspenx

The opamps I've tried so far sound better when biased to Class A. Albeit in varying degrees.


----------



## stau

Hello

 I greet all here in forum
 sorry for bad english I only had three years of the language at school and I was not the best 

 I have "lovely" before getting two days
 I bought everything including: alluminum box, connections, everything

 after 13 days, it was super na Germany

 the supplier as I said super packed, everything was great and so nice fast objectively

 I have connected it directly to NAD CD player, analog output

 12 hours I hear it and tell me everything is wonderful! The wide, airy, accuracy, better than Matrix M-Stage (I immediately sold)

 my headphones hifman HE5 works very well with "Lovely"

 I write more on this later


----------



## purrin

Quote: 





cya|\| said:


> I cannot find it.
> But is the 3.49 bias better than default? If so should i go for it to have a balance between performance/safety?


 

 Honestly, running with a 3.0mA or even 2.0mA bias is probably good enough to have the op-amp be in class A (and have its corresponding positive traits) considering its feeding a diamond buffer output stage.  The only reason to go above that is to tweak the sound balance, depending upon op-amp.  LM4562 / LME49720 get warmer with more current.  OPA2107 gets bright until 5mA, then it starts to get darker (6-7mA which is a lot).  I use the touch-test to check for how hot the chip gets, although I should mention it's not reliable since the transistors generator a lot more heat which tends to spread throughout.  The class A biasing only affects the chip, not the output stage (transistors).
   
  I'm am currently running 3.3k resistors with LM4562.  I'm now tending to run with higher value resistors (less current) because it seems going the other way tends to reduce dynamics and make things sound flat.  I'm seriously considering the use of 1N5xxx series CRDs instead of resistors - if I don't just grab the latest Burson's first.


----------



## dlaloum

Noooo - don't do that! I want a comparative report on the crd option!


----------



## sunneebear

Quote: 





stau said:


> 12 hours I hear it and tell me everything is wonderful! The wide, airy, accuracy, better than Matrix M-Stage (I immediately sold)


 

 Welcome to Head-Fi stau.  Good to hear a M-Stage and Lovely Cube comparison.


----------



## sunneebear

Quote: 





purrin said:


> if I don't just grab the latest Burson's first.


 

 I emailed Burson about the the safety of class A biasing.  The reply I got is that not only is it safe but I should get the same benefits as a IC.  Not so.  I am using 3.9 resistors on a adapter and the Bursons became extremely airy.  Focus and definition are lost.  I have not tried other values but direct seems to be more than good enough for now.


----------



## Cya|\|

Quote: 





stau said:


> Hello
> 
> I greet all here in forum
> sorry for bad english I only had three years of the language at school and I was not the best
> ...


 
   
  So you got it shipped to germany?
  How much did you pay for custom taxes?
  Also, what are the general custom taxes in Germany? Usually in Italy it's about 20%, but i'll live in Germany next year, and i'll receive several things from china and us 
	

	
	
		
		

		
			





.
  Did you prefer the lovely with default opamp to the matrix?


----------



## Bina

Hi, just one question. Stock opamps in lovely cube should be same as in Lehmann BLC?


----------



## stau

How much did you pay for custom taxes?


 >>>>>  19,95 %


 Did you prefer the lovely with default opamp to the matrix?

 Lovely standart OPA
 Matrix standart OPA


----------



## Cya|\|

Quote: 





bina said:


> Hi, just one question. Stock opamps in lovely cube should be same as in Lehmann BLC?


 

 If what i red on the web is correct, the answer is yes.


----------



## stau

I had possibility "Lovely" test them "Grado HP-1000"!

 great, wonderful recommendation!


----------



## francisdemarte

Stau:
   
  Since you've owned both the M-Stage and the Lovely Cube can you tell us how they compare?


----------



## ninjikiran

Quote: 





bina said:


> Hi, just one question. Stock opamps in lovely cube should be same as in Lehmann BLC?


 


  Yea OPA2134 the same stock opamp in the Lehmann BLC as it is  in the Lovely Cube, but it doesn't have to be.  There are better~


----------



## Bina

I know you can get better and I will probably get  one, but I would like to compare lovely cube directly to BLC.


----------



## stau

@fracisde....
   
   
  yes
 I had "Matrix M-Stage" is right! 1 weeks both

 and now I keep "Lovely"

 tested with headphones = Hifiman HE5, and borrowed HD800, Denon 7000, grado

 but he is my Hifiman 5


 - Low hum and noise at "M-Stage," "Lovely" is silent!
 - "Lovely" costs less, gold-plated RCA input, OPA easily replaceable
 - "M-Stage" has only 1 output for headphones
 - Bass in "M-Stage" little worse than "Lovely" but still good
 - Extremely wide stage "M - Stage" but "Lovely" has greater space
 - All instruments, can be separated and locatable wonderful, both the same
 - Both are proffesionel / better suited for ortho dynamic headphones
 - Exception HD800 headphones which were both very good!
 - Denon 7000 was not as good as HD800
 - "M Stage" and "Lovely" play a lot better with "Hifiman HE5" and "Grado HP-1000
 - Both processing, edge, screw, looks good
 - Both are warm but not hot after 3 hours, very good

 I have "Lovely" For me to keep slightly better
 End
  stau
   
  PS:  I had "The Matrix" mini-i "--- unfortunately, was very bad when I compare it with
 "Lovely"


----------



## aspenx

^ Good to know the LC is the winner!
   
  I'm odering another one! (not for balanced though)


----------



## LeonardS

I have the HLLY DMK-IV, which uses pretty much the same circuit for its headphone amp.  I love the DMK-IV's DAC, but the headphone amp is...just ok.  I'm really considering getting this "lovely" just to see if it sounds better than the built in version of it included with the HLLY unit.
   
  I could test any MOD work on the "lovely" before incorporating it into the HLLY unit.  I'd really rather have an DAC headamp combo, so my goal would be to get the HLLY sounding better.  All the talk on how good this "lovely" unit sounds has me wondering what could be done to get the HLLY unit to sound as good, considering it is the same design. 
   
  Is this a crazy idea?  Or should I just start the smd desoldering routine and start switching opamps in the HLLY?


----------



## dlaloum

First comment - the Lovelycube, Matrix M-Stage and Lehmann Black Cube Linear all use the same circuit design - there has already been one posting on here saying that the LC sounds better than the MS.... other reviews have compared BCL and MS and said they sound the same...
   
  Basically how the circuit is laid out and the quality of the parts will evidently change the sound - so although the design is well nigh identical - the implementation is not.
   
  If the LC sounds the same as the DMk-IV - then the same improvements via Opamps MIGHT (!) apply - differences in power supply regulation and current capability may change the sound as you play with opamps.... eg: OPA2604 has relatively poor power supply noise rejection - anything that comes through the power supply is likely to affect the sound far more than something like LT1028 (PSRR of 80dB vs 135dB - huge difference!)
  If Biasing in class A - you will need additional current capability - not a huge amount (say 10mA tops) - but it depends how close the PSU's design is to the units consumption - and whether it is stressed at peak times....
   
  In other words YMMV
   
  (But I am really enjoying the OPA637 class A in my M-Stage.....)


----------



## aspenx

Got myself another Lovely Cube and it came today. I got the Class A biasing adapters and the OPA627AUs from the seller too, so I'll be writing some impressions later after I burn in my capacitors.
   
  I've changed the Elna RE3 470uF 35V caps for equivalent Panasonic FM ones going to the buffer stage and Rubycon ZLH 680uF 35V caps going to the opamp. I don't see the need to bypass the 4 electrolytics to the buffer and my sources actually have some pretty bad DC offset so these re all the "mods" for now.
   
 Stephen had made some changes to the board, and here are pics of them:
  1. Nichicon KG Gold Tune 4700uF 50V replaces the Elna for Audio 4700uF 35V

   
  2. Different LEDs from the "first version"?

   
  More pics:
  3. Panasonic FM capacitors are taller and also fit into the same footprint

   
  4. So are the Rubycon capacitors seen here with the stock OPA2134

   
  5. OPA627AU with a Class A adapter

   
  6. LT1028ACN8s on DIY adapter

   
  7. And lastly the front with a naked pot shaft! (sorry for the colour cast, it was just a quick snap)


----------



## willaw

Aspenx, when did you place your order? I still haven't got mine yet.


----------



## aspenx

I ordered it a little more than a week back.
   
  Shipping from HK to here (Singapore) by registered mail has never exceeded more than 6 days for me. This particular package was at the local post office despatch centre already on Monday but I only got it on Wednesday. You might want to check with your local post office if you're having any unusual delays. If the seller has shipped it out, you should have received a tracking number from him.


----------



## myscoobysti

aspenx, are there any differences in the sound signature in stock form compared to your previous lovely cube that's using the Elna caps? Which is better, Elna or Nichicon?
   
  Btw, what camera are you using? Nice color.


----------



## aspenx

Quote: 





myscoobysti said:


> aspenx, are there any differences in the sound signature in stock form compared to your previous lovely cube that's using the Elna caps? Which is better, Elna or Nichicon?
> 
> Btw, what camera are you using? Nice color.


 

 There are 3 grades to the Nichicon KG if I'm not wrong. Their specs are slightly different. Seller claims that the Elna and the Nichicon he uses are of the same grade, but I believe the Nichicon could possibly be better.
   
  Hmm, it's hard to compare cos I don't have my first Lovely Cube anymore. My memory isn't very good. I haven't heard it stock with the Nichicon either because as I mentioned, I swapped out the Elna RE3 capacitors. Even with the OPA2134, it sounds verrrry good. I don't know if decoupling capacitors can have such big effects on the sound, but I think mine sounds more effortless and airy now. The OPA627 with the 3K ohm Class A bias adapter the seller also sells is great. I didn't think I'd like it this much. It's very engaging yet pretty detailed and non-fatiguing.
   
  Thanks. The pics were taken with Nikon D700 + Nikkor 60mm f/2.8 AF-D Micro + on-camera SB600 with cheapo cap diffuser.


----------



## willaw

Stephen saw this post and replied my email. Aspenx, I guess you ordered the finished board only. I OTOH paid for the fully assembled version. Oh well. 
	

	
	
		
		

		
			




  
  Quote: 





aspenx said:


> I ordered it a little more than a week back.
> 
> Shipping from HK to here (Singapore) by registered mail has never exceeded more than 6 days for me. This particular package was at the local post office despatch centre already on Monday but I only got it on Wednesday. You might want to check with your local post office if you're having any unusual delays. If the seller has shipped it out, you should have received a tracking number from him.


----------



## aspenx

Quote: 





willaw said:


> Stephen saw this post and replied my email. Aspenx, I guess you ordered the finished board only. I OTOH paid for the fully assembled version. Oh well.


 

 Oops. I should have been clearer. My bad.


----------



## myscoobysti

Quote: 





aspenx said:


> There are 3 grades to the Nichicon KG if I'm not wrong. Their specs are slightly different. Seller claims that the Elna and the Nichicon he uses are of the same grade, but I believe the Nichicon could possibly be better.
> 
> Hmm, it's hard to compare cos I don't have my first Lovely Cube anymore. My memory isn't very good. I haven't heard it stock with the Nichicon either because as I mentioned, I swapped out the Elna RE3 capacitors. Even with the OPA2134, it sounds verrrry good. I don't know if decoupling capacitors can have such big effects on the sound, but I think mine sounds more effortless and airy now. The OPA627 with the 3K ohm Class A bias adapter the seller also sells is great. I didn't think I'd like it this much. It's very engaging yet pretty detailed and non-fatiguing.
> 
> Thanks. The pics were taken with Nikon D700 + Nikkor 60mm f/2.8 AF-D Micro + on-camera SB600 with cheapo cap diffuser.


 

 Thanks for your reply. Does your Lovely Cube get hot running Class A like some of the Matrix M-Stage? I'm wondering if it'll affect the durability of the Nichicon caps since they are rated at 85C instead of Elna at 105C. They are very close to those heatsinks!
   
  One more question, if you don't mind (I'm a total noob), any particular reason for choosing Panasonic and Rubycon instead of other brands?


----------



## aspenx

Quote: 





myscoobysti said:


> Thanks for your reply. Does your Lovely Cube get hot running Class A like some of the Matrix M-Stage? I'm wondering if it'll affect the durability of the Nichicon caps since they are rated at 85C instead of Elna at 105C. They are very close to those heatsinks
> *Yes, it does get pretty warm. The big reservoir caps are nothing to worry about though. I can place a finger on it for as long as I want. It wouldn't even hit 50C.*
> 
> One more question, if you don't mind (I'm a total noob), any particular reason for choosing Panasonic and Rubycon instead of other brands?
> ...


----------



## myscoobysti

aspenx, thanks for the lesson on caps. I appreciate very much and glad to know that those Nichicon caps don't get that hot.


----------



## dlaloum

With regards to the question re: Heat and the Class A mod
   
  Although the opamps being modded do get hot, the major source of heat in there is the buffer stage which is unchanged.
   
  Overall impact of the class A mod in terms of heat is negligible.
   
  However - this amp does run warm (at least in standard M-Stage form) - but in Lovelycube form it would depend on the case design and construction - if you put it in a case with air circulation (ie one with slots/holes) this would reduce heat build up (and potentially allow a heatsink on the opamp and biasing deeper into class A - sonic benefits unknown)
   
  Or a closed case with larger surface area, (maybe a case designed for heatsinking)...
   
  In any case the pure class A buffer with discrete transistors is going to be generating more heat than the opamps.


----------



## DaEMoNteNTAcLe

i used to have a pure discrete class A amp on loan.
  it does a few things better than the lovely cube stock if properly heated up. if running cold it have very compressed dynamics, very harsh sounds, grainy, etc.. you name it.
  but heated up, it is simply marvelous. when i say heated up, the casing is very hot to the touch, easily said u can make a half cooked egg if u leave it on the case. now that is pure class A.
  i have a time i was listening, and i noticed the sound gradually becoming dull.. it really a What kinda moment.. until i realized it was raining that day..
  neways my lovely cube with lm49820na biased with 10.2kohm resistor actually sounded quite close to the discrete class A, minus some refinement, but without the need to heat them up.
  i wouldnt mind the heat actually, caps are made to withstand 300degree soldering iron heat anyways. im more concerned on the opamp limitation on heat.
  both amps are able to drive my cans close to what yamamoto ha-02 is capable (side by side comparison). yammy have an unbelievable background blackness on it that pops miniscule detail like bright star on the black skies tho. but for what i paid, lovely cube linear is really a damn good amp.
   
  i also seems to just receive a package from hk, would be from stephen. I have to say, he always replies prompt, and ship fast.. it reach my shore the next day, and stuck in customs for a week.. -_-.


----------



## T.IIZUKA

I ordered last night. 
	

	
	
		
		

		
		
	


	



   
  It introduced the amplifier with Blog. (Japanese text only)
http://tiiduka.blogspot.com/2010/10/lovely-cube-headamp-2.html


----------



## aspenx

Quote: 





daemontentacle said:


> i have a time i was listening, and i noticed the sound gradually becoming dull.. it really a What kinda moment.. until i realized it was raining that day..
> neways my lovely cube with lm49820na biased with 10.2kohm resistor actually sounded quite close to the discrete class A, minus some refinement, but without the need to heat them up.


 
   
  Wah. Too extreme lah. haha. And you're biasing with such a small bias current? Have you tried other values with the LM49820na and why did you settle with 10.2k?

  
  Quote: 





t.iizuka said:


> I ordered last night.
> 
> 
> 
> ...


 

 >部品代だけでも結構な金額になるんじゃないの？
   
  同感ですｗ
  あぁ、部品と言えばOPAMPはTIではなくて、BBのOPA2134ですよ。


----------



## DaEMoNteNTAcLe

well that's the only resistor i have atm..
  will try the new package from stephen this weekend. im hopin 627 and more bias will do some magic.. 
	

	
	
		
		

		
		
	


	



  for pure class A, its' not extreme, rather, it's typical. All class A performs only after warm-up. it happens on even the expensive lavry da-11 which also uses class A for its amp, this was tested at my friends house. the circuit needs some steady current running for it to work well, and it seems heat is one of the indication, as well as byproduct of it.
   
  tonikaku sore wa omoshiroi desu ga,
  ore wa zenzen yomenai yo. kanji ga shiranakute... xD


----------



## T.IIZUKA

Quote: 





aspenx said:


> >部品代だけでも結構な金額になるんじゃないの？
> 
> 同感ですｗ
> あぁ、部品と言えばOPAMPはTIではなくて、BBのOPA2134ですよ。


 
   
  BB=TI's Brand 
  
  TI acquisitions BB in 2000.  ($7.6 billion)


----------



## aspenx

I'm sure you'll like the OPA627 and the bias adapters. I'm really liking mine with the 3k adapters from Stephen. So much so that I haven't tried my LT1028s (and also because I think I toasted the adapter with bad soldering). I wanted to write my impressions on the OPA627 and the adapters but I'm stumped. What more is there to say but "gooooooooooooooood"? I'm definitely listening to my music more than worrying about gear now anyways.
   
  So, how do you suggest we listen to Class A gear on rainy days? There are no "cold" days here in Singapore nor in M'sia so it's a good thing? I still can't believe heat is an "indication" of performance really. >< I shorted the transistors on my previous LC once and the heat (and smell!) didn't do any good at all....... haha
   
  The M-Stage has its voltage regulators and transistors all mounted vertically. Maybe doing that might be able to ease my worries with using the amp with Class A biasing. I keep my amplifier switched on almost 24 hours a day by the way...

  
  Quote: 





t.iizuka said:


> BB=TI's Brand
> 
> TI acquisitions BB in 2000.  ($7.6 billion)


 

 Oops. I made yet another boo-boo. If it means anything, the opamp is marked with "BB". I also read that those marked as "BB" are more laidback in sound than the TI versions. Is this true?


----------



## T.IIZUKA

I own a lot of OPAMP. It looks forward to Lovely Cube's reaching and doing OPAMP Rolling. 
  
  Quote: 





aspenx said:


> Oops. I made yet another boo-boo. If it means anything, the opamp is marked with "BB". I also read that those marked as "BB" are more laidback in sound than the TI versions. Is this true?


 
   
  TI OPA2134
http://focus.ti.com/docs/prod/folders/print/opa2134.html
  
  It is a difference of the difference extent of Lot. 
   
   
  It seems that industrial OPA2132 is a base. 
  It varies in price from OPA2134. 
   
  OPA2132
http://focus.ti.com/docs/prod/folders/print/opa2132.html


----------



## DaEMoNteNTAcLe

well on that day, after i found out it was raining, i just wrap the amp in a wool cloth, after that i slowly regain the dynamics and smoothness.
   
  anyways, just plugged the opa627.. and DAMN it really DOES magic. probably on par with my lm49820 10kohm biased. The improvement from small current bias on the lm49820 was actually enough to make me really happy.. and opa627 is able to do that unbiased.. tonight seems to be a short night..
	

	
	
		
		

		
			





..
   
  btw.. forgot to add.. imho lovely cube is not an amp that needs warmup. i cant seem to find any difference between maintaining its heat and running cold.


----------



## aspenx

I assume you received the bias adapters too?
   
  Try them out with both the OPA627 and LM49820 and let us know what you think! One night is definitely not enough.


----------



## francisdemarte

Quote: 





aspenx said:


> Oops. I made yet another boo-boo. If it means anything, the opamp is marked with "BB". I also read that those marked as "BB" are more laidback in sound than the TI versions. Is this true?


 

  
  The BB I believe stands for Burr-Brown which was acquired by TI in 2000. BB's op amps and DAC's generally are known for their more laid back sound.


----------



## DaEMoNteNTAcLe

first of all..
  sry for the wrong info.. i kinda mixed up 49720 and 49860.. i was using 49860. and yes i got the adapter with it.
  anyways, comparison :-
   
  49860 w 10k - almost same separation and quality with 627, more depth than 627, very noticable. vocals are not as organic as 627.
  49860 w 5k - more bass thud, and slightly more quiteness in the background, but vocals are slightly dryer.
  49860 w 3.3k - similar improvement, but vocals are dryer as well.
  49860 unbiased - totally below 627, noisy and sibilant, otherwise extended upper and lower freq and more balanced sounding along frequency compard to stock 2134.
   
  627 w 5k - more depth, warmth, and bass weight and impact. i found it too warm and intrusive already, mids details are drowned.
  627 w 3.3k - more bass weight and impact, not sure whether its warm or not.. but i kinda feel i dont like it.
   
  627 is more pleasing on vocals with slightly better tone on the highs compared to 49860.
   
  im not sure whether the adapted will affect much, Also i might solder the resistor directly to the 627, but still deciding. As of now, i'll probably gonna go get some 7k resistor to try out instead. or if anyone have a better suggestion?
   
  one night might not be enough for full testing, but it is quite enough for me to favor the biased 627 minus warmth.


----------



## ninjikiran

Not a lovely cube question but is there any bodies or top halfs I can put on with vents for my M-Stage?  Mines runs hot, I assume its cause the case is acting as a bootleg heatsink.  It might lengthen the life of the unit.


----------



## dlaloum

Quote: 





ninjikiran said:


> Not a lovely cube question but is there any bodies or top halfs I can put on with vents for my M-Stage?  Mines runs hot, I assume its cause the case is acting as a bootleg heatsink.  It might lengthen the life of the unit.


 


  I think someone posted pictures of theirs with rows of holes drilled into the top for airflow..... so that is always an option...
   
  And I agree that it runs hot - but not dangerously so....


----------



## darknight670

WoW is the Lovely cube really BETTER than the M Stage?


----------



## seagrasser

I have pulled the trigger based on great review and personal expereince here. I can't wait to try this "Lovely" amp out.


----------



## aspenx

Quote: 





daemontentacle said:


> one night might not be enough for full testing, but it is quite enough for me to favor the biased 627 minus warmth.


 

 I find it a little too warm too. That's why I like my LTs but it's very hard to choose one over the other. Anyways, I've taken out the input coupling capacitors and it's not as warm now.


----------



## purrin

Quote: 





aspenx said:


> I find it a little too warm too. That's why I like my LTs but it's very hard to choose one over the other. Anyways, I've taken out the input coupling capacitors and it's not as warm now.


 

 yup - the input caps have a large impact on the overall warmness of the amp.


----------



## lyramax

Quote: 





> Originally Posted by *francisdemarte* /img/forum/go_quote.gif
> 
> ...
> 
> ...


 

 Are the two amps equally conducive & versatile in terms of simple swapping of op-amps?


----------



## francisdemarte

Yes they are. Swapping the op amp is exactly the same on both amps.


----------



## aspenx

Quote: 





dlaloum said:


> I think someone posted pictures of theirs with rows of holes drilled into the top for airflow..... so that is always an option...
> 
> And I agree that it runs hot - but not dangerously so....


 
   
  I'm not sure most of us will be willing to deal with case work actually. Or maybe I just belong to the minority...
  
  Anyways, Stephen the LC seller, mentioned that he's looking at ways to reduce this heat a little to address concerns.
   
  I'm looking forward to the mods and hope they'd be available to people who have already got their Lovely Cubes too.


----------



## dms

Quote: 





dlaloum said:


> And I agree that it runs hot - but not dangerously so....


 


 I don't have Lovely Cube but another Black Cube clone that looks exactly the same so I think I can share my findings here: I did some measurements with my IR thermometer and found out that after a few hours of playback the temperature near the output transistors goes up to 65C/149F (transistors themselves are a few degress cooler). The temperature around voltage regulators is also a litlle high, up to 55C/131F. Operational amplifier runs at around 50C/122F. As you say these are probably not critical temperatures. Transistors, resistors and diodes should probably take a lot more than that and electrolytic capacitors should probably take at least 85C/185F but more likely 105C/221F or even more.
   
  Don't worry, be happy, it's hot music coming out of your amp.


----------



## francisdemarte

All this heat talk worries me as my LC doesn't only gets warm. After leaving it on all day playing music I can still put my fingers on the heat sinks.
   
  Maybe it's less noticable for me because my LC is in a plastic case. I have holes drill on the sides close to the top was well as holes on the bottom of the unit. I think this creates a minor chimney effect where as heat rises and escapes through the hole on top, cooler air is drawn in on the bottom. 
   
  Are there any openings at all on the case supplied by Stephen?


----------



## aspenx

Quote: 





francisdemarte said:


> Are there any openings at all on the case supplied by Stephen?


 


  The only openings are for the DIP switches. I wouldn't even try putting my finger on any of the transistors or voltage regulators on mine.


----------



## DaEMoNteNTAcLe

just found out both sides (from front panel, left and right side) of the LCL needs to be on about same temp..
  it also needs some warm-up time to sound smoother and more controlled bass, typical class A, but not as much as true class A.
   
  u can try cooling just half side of the board, eg.. expose one side to air and cover the other half..
  u will notice channel imbalance, and also one side will sound brighter/harsher. this will go away once both are on about same temp.


----------



## stau

opa 267 3.49 mA from Stephen has been running for 3 days at me almost without pause
 opa is hot
 aluminum housing is also slightly hot

 sounded

 bass is much better with hifiman HE5


----------



## Nialpo

Is it ok for 4 output transistors on radiators to be burning hot? After about one minute, I can't just touch them for longer than 0.5 sec
  (However, it is not instantly burning my fingers, so i assume temperature is lower than 100 C )
  Two stabilizators are just warm.


----------



## lyramax

Does the "heat issue" exist with the regular stock amp or only with bias modded version?


----------



## dlaloum

Yes this is normal - the 4 transistors run in pure class A mode as stock.....
   
  The class A mod only moves the opamp from class AB to class A - so additional heat is only generated by the opamp itself.
   
  The lovelycube, mstage and Lehmann black cube all run very warm as the buffer stage is pure class A.


----------



## stau

opa627 5 mA  with hifiman he5 
   
  sounds hol, quietly, without life

 I have now is expanded in the drawer


----------



## francisdemarte

Must put in an order for some resistor so I can try this Class A mod. So everyone agrees 3.49 mA sounds the best?


----------



## dlaloum

Quote: 





stau said:


> opa627 5 mA  with hifiman he5
> 
> sounds hol, quietly, without life
> 
> I have now is expanded in the drawer


 
  5mA is at the high end ...
   
  You may not like the OPA627 sound - the OPA637 has more high end... you may want to read the opamp rolling threads .... an LT1028ACN8 might be more to your taste.... or an OPA2604 - there are A LOT of options


----------



## dlaloum

Quote: 





francisdemarte said:


> Must put in an order for some resistor so I can try this Class A mod. So everyone agrees 3.49 mA sounds the best?


 


  Have a chat to Purrin - and make sure you read the M-Stage thread as well as this one - Purrin experimented with various levels of biasing on the OPA627 and ended up settling around the 3.5mA level (more was too warm, less was not as open...)
   
  Theoretically the level that keeps the opamp in class A with the load you provide is what will sound best..... practically you play it by ear (including related psychoacoustics) and pick what sounds best.
   
  There's a lot of variables there though !! (just with Opamp choices and level of biasing)


----------



## stau

hi to my ears with hifiman HE5 +  lovely cube

 OPA627 3.49 mA -- super  instruments  and very good bass

 OPA627 5 mA --  instruments too flat bass is not good enough
   
  edit
   
  what do you think about

 AD8599 or OPA2228


----------



## dlaloum

Quote: 





stau said:


> what do you think about
> 
> AD8599 or OPA2228


 
  I have not listened to AD8599 (don't have one!)
   
  I had a short listen to 2x OPA228 on a dual adapter (in class A) it sounded good but not as good as the OPA627/637
   
  I decided on a longer term (weeks) listen to the OPA637 and just recently returned to the OPA627 - decided I prefer the 627 over the 637....
   
  I am now giving my ears time to re-aclimatize to the 627 before trying something else (maybe I'll give the 228 a serious listen)
  
  My list of OPAMPS
   
  OPA2132/2134 - baseline
  OPA627 much better
  OPA637 better than 2132 but ultimately fatiguing - prefer the 627
  OPA228
  AD797
  LME49860
  LME49720
  LTE1028ACN8
  H3-2525
  AD744
  OPA2604
   
  Can you tell why this is taking a LONG time....!
   
  So far I have had a brief listen to all of them in both Class A and standard mode.... nothing critical, and nothing really stood out (no real duds), only the stock 2132, 627 and 637 have had critical listening time - the OPA627 class A is very pleasing, and if it weren't for the fascination of exploring all these options, I would settle for this one in a flash - it has a well deserved reputation.
   
  I also tested all of them with RMAA - and there were some differences in noise profiles, as well as distortion and hash especially at low or unity gain levels. (several of these are happier at higher gain.... my headphones are DT880/600 so this is not an issue - I need the gain!)
   
  As an aside - the RMAA testing also allowed me to identify some interference that was being caused by cooling fans I had placed on top of my Receiver (which was acting as the DAC) - I have since removed the fans.... as well as done additional work on EMI/RFI proofing and properly grounding the entire rig.... this has made measurable differences to RMAA measurements, and slight but noticeable differences in sound. - Prime difference is that the sound is smoother and less fatigueing.


----------



## T.IIZUKA

Assembly ended in my Lovely Cube.
  After shipment only. 
   
  Photos from Stephen.
   

   
  Great!


----------



## francisdemarte

Congrates on joining the LC family!


----------



## Cya|\|

Just got it. Waiting for 1 week burn in at least. The bass is not very powerful, but i guess that´s due to the lack of burn in.


----------



## francisdemarte

Quote: 





cya|\| said:


> Just got it. Waiting for 1 week burn in at least. The bass is not very powerful, but i guess that´s due to the lack of burn in.


 


  What headphones and gain are you using?


----------



## Cya|\|

Quote: 





francisdemarte said:


> What headphones and gain are you using?


 

 What´s the gain sorry? My headphones are the audeze lcd-2.
  The bias is the soft one (3.something ampere). the opamp is the 627.


----------



## francisdemarte

If you turn the amp over you'll 4 switches with numbers on them like this:
   

   
  These are the gain switch that control the level of amplification that the amp is using. You may need to increase it, not sure what everyone else is using for the LCD-2's.


----------



## Cya|\|

Does it only increase the volume? So far, with the pot at half (it has a stepped pot) i can hear to imploding levels.


----------



## DaEMoNteNTAcLe

anyone tried less than 3.49mA?
  i found the vocals already too dry, and worse at 5mA.
  unbiased 627 still have best organic vocals.. but it really lacks depth. -_-
   
  btw.. if just retaining opamp, how does the gain affect the sound?
  my board is still on the acrylic, so i cant access the gain switch without unscrewing..


----------



## stau

I hifiman HE5 with lovely cobe opa267 and 3.49 mA
 To me it sounds very good (but very bad 5mA!)

 I Gain on MAX

 BASS - is with me too little. Everything else still well balanced


----------



## Cya|\|

Quote: 





stau said:


> I hifiman HE5 with lovely cobe opa267 and 3.49 mA
> To me it sounds very good (but very bad 5mA!)
> 
> I Gain on MAX
> ...


 

 The bass it too little with my lcd-2 too. I don´t know if it´s a burn in issue. What does the gain do? Does it only increase the volume or also do something else?


----------



## stau

Volume only


----------



## francisdemarte

I don't believe that your lack of bass is normal. Email Stephan and ask for some troubleshooting advice.
   
  Post your bass issue in the M-Stage thread to see if other LCD2 owners also experience the same level of bass.
  What other amp are you using?
   
   
  You can also try
   

 different gain settings
 Removing the Class A adapter
 using a different opamp
 
  
  Quote: 





cya|\| said:


> The bass it too little with my lcd-2 too. I don´t know if it´s a burn in issue. What does the gain do? Does it only increase the volume or also do something else?


----------



## stau

hi
 I have a problem with BASS in my hifiman HE5

 maybe it's normal?

 in M-Stage I had the same

 perhaps the ortho .. headsets are so! no BASS
   
   
  PS:    if you find solution please write me and mail


----------



## Cya|\|

Dunno, there is bass, but not like i would have expected from these headphones who can extend down to 10hz. But it´s not like there is no bass.
  By the way, what is the difference between the 2 plugs? Wich one do you use? Right now i´m using the left one (the furthest one from the pot).


----------



## aspenx

Quote: 





cya|\| said:


> Dunno, there is bass, but not like i would have expected from these headphones who can extend down to 10hz. But it´s not like there is no bass.
> By the way, what is the difference between the 2 plugs? Wich one do you use? Right now i´m using the left one (the furthest one from the pot).


 


 Are you using the stock opamp? IMO, there is quite a bit of bass in the OPA2134 but it's bloated, not precise and doesn't go very deep. There are many other better opamps for much deeper and better bass.


----------



## dlaloum

Quote: 





daemontentacle said:


> anyone tried less than 3.49mA?
> i found the vocals already too dry, and worse at 5mA.
> unbiased 627 still have best organic vocals.. but it really lacks depth. -_-
> 
> ...


 

 Look  for Purrin's posts in the M-Stage thread....
   
  Also the results are dependent on your HP's as the class A mod raises the voltages at which the opamp remains in class A - once the voltage passes a certain threshold, it reverts to class AB.
   
  600ohm HP's require more voltage - and are therefore more likely to push out of the envelope .... if you are running with 50ohm HP's or lower - the likelihood of being in class A is substantially increased.
   
  All opamps that I tested showed noise/distortion spikes when run at 0 gain - 10db gain is the minimum to get rid of this. I think this is telling us something about opamp stability at 0 gain - many opamps specifically state in their specs that they are unstable at 0 gain.... but even those that are supposed to be stable are showing this trait.
   
  So there you go - a few more variables to work through...


----------



## stau

Ports to amplifers  check

   test 1 --- back to chinch  at amp  ..   + lovely cube connected - no bass at hifiman HE5

   test 2 --- forward to the headphone output at amp ..  +  lovely cube connected - BASS on hifimann HE5 there !!!!!!!!!!!!!! BASS is here! super

 what does that mean?


----------



## francisdemarte

Quote: 





stau said:


> Ports to amplifers  check
> 
> test 1 --- back to chinch  at amp  ..   + lovely cube connected - no bass at hifiman HE5
> 
> ...


 

 Stau:
   
  Not sure if I understand what you mean.
   
  Did you try a different output on your source? Source headphone out ---> Lovely Cube? What is your source?


----------



## stau

I did test the hi-fi amplifier + lovely cube

 1 out of the amplifier chinch> lovely cube
 2 out headphone output <lovely cube

 and found that I had the headphone amplifier output of more bass than the chinch


----------



## francisdemarte

Okay I understand now, chinch = RCA connectors to us Americans. So the line out from your hi-fi has less bass then the headphone out of your hi-fi. 
   
  So there is bass roll off from the line out of the hi fi amplifier or else the hi fi's headphone amplifier is pumping up the bass. You probably do not want to use your hi fi's headphone out because then you will be amplifying the signal twice.
   
  Find out why there is less bass on your hi fi's line out when connected to the Lovely Cube. What is in front of the hi fi amplifier (CD/DVD/turntable/computer?) Can you connect the Lovely Cube directly to it?
   
  What brand / model is your hi fi?


----------



## Cya|\|

Quote: 





aspenx said:


> Are you using the stock opamp? IMO, there is quite a bit of bass in the OPA2134 but it's bloated, not precise and doesn't go very deep. There are many other better opamps for much deeper and better bass.


 

 627.
  Is there a difference between the 2 plugs?
  Unfortunately i don´t have a screw, so i cannot even change the gain to 10.


----------



## aspenx

Quote: 





cya|\| said:


> 627.
> Is there a difference between the 2 plugs?
> Unfortunately i don´t have a screw, so i cannot even change the gain to 10.


 

 You mean a difference between the 2 sockets? The 2 sockets produce the same output. The one nearer to the potentiometer goes directly to the "output" which I suppose you have left unconnected.
   
  Why would you need a screw to change the gain? You could just flip the unit over and use your fingers?
   
  I'm using 2x LT1363. The bass goes deeper and it's more precise. Although the quantity of the overall bass is less than the OPA627, the quality makes up for it. I don't know if that's what you're looking for but you could try out a LT1364 for pretty cheap if you need to.


----------



## Cya|\|

Quote: 





aspenx said:


> You mean a difference between the 2 sockets? The 2 sockets produce the same output. The one nearer to the potentiometer goes directly to the "output" which I suppose you have left unconnected.
> 
> Why would you need a screw to change the gain? You could just flip the unit over and use your fingers?
> 
> I'm using 2x LT1363. The bass goes deeper and it's more precise. Although the quantity of the overall bass is less than the OPA627, the quality makes up for it. I don't know if that's what you're looking for but you could try out a LT1364 for pretty cheap if you need to.


 

 I mean, how do i open the case to change the gain without screw?


----------



## DaEMoNteNTAcLe

@dlalom
  thx for the info.. didnt know headphone impedance affects.
   
  @aspenx
  2x LT1363 = less bass and better quality? how so? mind sharing more details coz i think the bass is still too much on the 627, biased or not.. kinda bloated in a sense, at least.. for my cans.


----------



## aspenx

Quote: 





daemontentacle said:


> @aspenx
> 2x LT1363 = less bass and better quality? how so? mind sharing more details coz i think the bass is still too much on the 627, biased or not.. kinda bloated in a sense, at least.. for my cans.


 
   
  Yea, I agree with you about the OPA627. I'm using the 2x LT1363 with no biasing. It is even better than the LT1364, biased or not. My JFETs just arrived yesterday. I'll be trying a more proper bias underboard when I get home. Will let you know more after I give the current setup a little more listening later.
   
  Have you tried the amp with LT1364?


----------



## DaEMoNteNTAcLe

Quote: 





aspenx said:


> Quote:
> 
> 
> 
> ...


 
   

 [size=medium]nope. gotta find one. i know where to find lt1361 here, but not lt1363 or 1364.
  isnt lt1363 just a single channel version of the lt1364? hm...
  i think im gonna try it later once i know where to find them.
  anyways good luck on ur mods.​[/size]


----------



## T.IIZUKA

Arrived!
   
  Talema 30VA Toroidal was printed with the name.
   

   
   
  RCA Connector
   

   
   
   

  [size=medium] First. [/size]
 [size=medium] The sound is good.  ＼(^o^)／[/size]
 [size=medium] It is happy to do barn-in. [/size]

   
  Right channel RCA connectors on the bottom.
  Channel had been left a red mark.
  Initially, the left and right a wrong connection.
   
   
   
  The screw that fixes a right side doesn't shut. 
  Right-side head of the screws on the metal case was burred.
  Recommended to increase the thickness or welded nut.
  It can be implemented cost is up slightly.
   
   
  Posted on Blog. (Sorry, Japanese-text only)
http://tiiduka.blogspot.com/2010/11/lovely-cube-headamp-5.html


----------



## Cya|\|

I´ve lowered the gain from 20db to 10db. Only change was the volume. But maybe the background is cleaner.


----------



## stau

"Initially, the left and right a wrong connection."
   
   
  have you re-soldered OUT


----------



## T.IIZUKA

Quote: 





cya|\| said:


> I´ve lowered the gain from 20db to 10db. Only change was the volume. But maybe the background is cleaner.


 


   
  I have a comfortable volume.
  What RK27 traded?


----------



## Cya|\|

Quote: 





t.iizuka said:


> Quote:
> 
> 
> 
> ...


 
   
  Sorry, I don´t understand what you said.
  I have a steppet potentiometer, one that the amp seller sells (you can find them in his ebay shop). I only paid +10$ for the stepped pot, and I´m happy I made that decision.


----------



## ViciousXUSMC

What do you guys think of the "economy edition"
   
  http://cgi.ebay.com/LOVELY-CUBE-Headphone-Amplifier-KIT-Economy-Edition-/200541739530?pt=LH_DefaultDomain_0&hash=item2eb1381a0a
   
  its not the same board and no opamp but other than that its the same right?
   
  looks like a good soldering project for me.


----------



## T.IIZUKA

Quote: 





cya|\| said:


> Quote:
> 
> 
> 
> ...


 
   
  Sorry, "volume" is potentiometer.
  RK27 is a potentiometer that has adhered to Lovely Cube. (ALPS RK27)


----------



## T.IIZUKA

Quote: 





viciousxusmc said:


> What do you guys think of the "economy edition"
> 
> http://cgi.ebay.com/LOVELY-CUBE-Headphone-Amplifier-KIT-Economy-Edition-/200541739530?pt=LH_DefaultDomain_0&hash=item2eb1381a0a
> 
> ...


 

 lower grade capacitors and resistors.
  Lovely Cube is being used more difficult to obtain parts.
   
  I think kit is $89 deal.
  (Deal of the Finished Board $99 more.)


----------



## ViciousXUSMC

Ahh with lower grade parts I would not be interested.  Plus only $10 for a finished board is a deal compared to the $89.00 kit.  Most people that do DIY for you charge way more than $10 for the labor.


----------



## DaEMoNteNTAcLe

after some brief tweaking...
  i end up changing from opa627 to lme49860na biased with 7.5kOhm.
  gain set to 20.
  i noticed that changing gain changes the sound quite a bit after biasing.
  im also using dual ground wire with both shield grounded at one end.. but havent finalized yet.. improves a bit of clarity, but also seemed to sound messy. will be tweaking more later after some burnin..
   
  currently only prefer using 627 unbiased.. but imho its too messy and lack depth. -_-
  biased have too much pounding bass and too dry on the vocals. seems like going below 3mA also isnt a good idea with 627, not clean sounding enough.
  dunno if i should go for 1361.. cant find 1364 where im staying now.


----------



## francisdemarte

Did some minor tweaks. Removed the output caps and moved those darn gain switches to the top of the board. I don't understand why there are two of them. Why would anyone want to have 2 difference gain settings on the left and right channels...going to replace them with 1 switch.
   
  Coming up: Ordering another board a going balanced!


----------



## ninjikiran

The rare chance one of your ears is damaged greatly  Though I doubt that was the reason why.
   
  The real reason might just be the way the circuit is designed.
  Quote: 





francisdemarte said:


> Did some minor tweaks. Removed the output caps and moved those darn gain switches to the top of the board. I don't understand why there are two of them. Why would anyone want to have 2 difference gain settings on the left and right channels...going to replace them with 1 switch.
> 
> Coming up: Ordering another board a going balanced!


----------



## VictoriaGuy

Just a general FYI-
  I ordered a Lovely Cube from Stephen a month ago. It arrived here in BC (Canada) yesterday, right on schedule.
  Very high quality assembly- everything fits perfectly, very neat wiring, nice touches like locking lacquer on board mounting screws, the switch access holes in the underside are properly located and finished, etc.
  It definitely doesn't have any DIY flavour at all!
  Sounds good as well.
  I'm happy.
  Total price including shipping was $231 Cdn.
  The support and communications from Stephen are first-class. There was a minor problem (wrong IEC cord) and Stephen replied via email almost immediately. Within a couple of hours I had a small refund back in my PayPal account. You really cannot ask for more that that!
   
  Cheers
  John


----------



## T.IIZUKA

Today's Lovely.
   

   
   
  Heat capacitor. Plans to measure heat.
  3-Terminal regulator's Heatsink touch with the capacitor. This seems to be the cause.


----------



## stau

hi
   
  I use OPA2134 original again - bigger room / stage little bass

 opa267 was somehow more bass but less room / stage


----------



## T.IIZUKA

Quote:


t.iizuka said:


> Heat capacitor. Plans to measure heat.
> 3-Terminal regulator's Heatsink touch with the capacitor. This seems to be the cause.


 
   
   
  Mr. Stephen did the answer to my question.
  Made a great page.
   
  http://www.alicemagicbox.com/lasercollection/lovelycubesecretofheat.html


----------



## stau

*super  !!! thanks for link*


----------



## francisdemarte

Thanks for the link! I think that will put a lot of people's minds at ease.


----------



## SP Wild

I've built up two of these silicon chip headphone amplifier boards and I own a Lehmann Black cube Linear.  The circuits have the same topology,  opamp input, same transistors for current gain and voltage regulation 
  (317/337)on a separate board.  The only major difference I can see is that the BCL has no feedback going back into the opamps and the silicon chip one does.
   

   
  I could not get the silicon chip board to equal the BCL in technicalities...there was always something that constrained the transparency and speed of the silicon chip boards - I removed the zobel network, the output inductors, replaced the diodes for ultra fast ones in the psu board, uprated all electrolytics to lower esr and higher capacity units...I got more detail out of it than the BCL...but still something was smothering the sound.
   
  Until I removed the input capacitor...that finally unleashed the silicon chip board to be as fast as the BCL amp...but the modified silicon chip board has lower sub bass extension and extra lower midrange detail because of this.  The kit cost Aus $37 for the amp board and $20 for the PSU board from Altronics or Jaycar in Australia ...all you need then is a toroidal for your country's AC voltage.  I will modify the second board and balance both boards.
   
  I thought I would post this up on this thread being an owner of the original $1000 BCL and this board sharing an almost identical topology.


----------



## aspenx

sp wild said:


> I've built up two of these silicon chip headphone amplifier boards ...




I don't think I follow you. Could you post a link to the board you're talking about? Is this your personal implementation?


----------



## SP Wild

Quote: 





aspenx said:


> Quote:
> 
> 
> 
> ...


 


http://www.altronics.com.au/index.asp?area=item&id=K5503
   
  Link to the amplifier kit from Altronics Australia - actually only $34 with the bits included
   
http://www.altronics.com.au/index.asp?area=item&id=K5501 
   
  The accompanying PSU board for $20
   
  By not installing some of the components that come with the kit...I guarantee it will meet the objective performance of the BCL.  Fitting higher capacity low esr capacitors will get more subbass extension and subjectively surpasses the BCL performance.  The caveat being you need to make sure that your source has very little DC offset, as the key for me was eliminating the input capacitor.  I goes to show that the BCL is a highly tuned device as it does what it does whilst being strangled by an input capacitor.  (I will not mod the $1K + BCL...but rather sell it)


----------



## francisdemarte

I've read quite a few positive reviews of this amp over at Rockgrotto. Seems like a good deal for a basic amp kit.
   
  Though the Lovely Cube seems to have an edge parts wise. For a bit more money you get bigger caps, a decent volume pot, selectable gain, and a beefier power supply that is integrated into the board. 
   
  Might pick a board up to experiment with!


----------



## sunneebear

Kind of looks like the economic lovely cube amp.
   
  http://cgi.ebay.com/LOVELY-CUBE-Headphone-Amplifier-KIT-Economy-Edition-/200541739530?pt=LH_DefaultDomain_0&hash=item2eb1381a0a


----------



## SP Wild

They do look remarkable similar.  The main advantages of the Jaycar Headamp (more commonly known as), is the offboard PSU board, whereas all the BCL and clones have the PSU integrated.  It just gives more flexibility for boxing.  I plan to have the transfomer and PSU (X2 for dual mono bridged) in a separate chassis from the audio circuits.  Also worth mentioning is that the Jaycar amps have a more symmetrical and cleaner layout for left and right channels - not that it would make any difference in sound quality.


----------



## Cya|\|

I have the gain set at 20db. Can i keep the volume at 14 o´ clock without risking to burn the amp?
  I use that volume when I don´t wear the headphones, and use them as a sort of speakers 
	

	
	
		
		

		
			





. The headphones do not have any problem, as they can sustain up to 15w, but I´m worried about the amp.


----------



## francisdemarte

Should be no problem. Just be careful you don't forget and put on the headphone on your ears and turn on the amp at that volume setting.

 Might considering getting actual speakers too


----------



## Cya|\|

Eheh, I only tried once wearing the headphones at that volume, and that was no fun experience 
	

	
	
		
		

		
		
	


	




. I live in a student dorm now. At my home I have speakers that are much better than the lcd-2. I would have bought a pair of adam a7x if noise wasn´t a problem...i must not disturb the other guys.


----------



## lyramax

Has anyone tried out one of the Audio-GD HDAM with the Lovely Cube?  Is there enough room near the RCA terminals at the back to fit one of these?


----------



## Cya|\|

Quote: 





lyramax said:


> Has anyone tried out one of the Audio-GD HDAM with the Lovely Cube?  Is there enough room near the RCA terminals at the back to fit one of these?


 


  He has to make special adjustments for you, wich costs +20$ I think.


----------



## avexdevil

which is the better opamp  recommended to couple a k701?
   
  opa earth or the opa 627?


----------



## T.IIZUKA

Quote: 





avexdevil said:


> which is the better opamp  recommended to couple a k701?
> 
> opa earth or the opa 627?


 


   
  Listening to music is what I found in the Profile.
  How sound while K701?
  I have never tried, "OPA Earth" to.
  In OPA627AU than OPA2134, I think that rich bass.


----------



## aspenx

Quote: 





avexdevil said:


> which is the better opamp  recommended to couple a k701?
> 
> opa earth or the opa 627?


 

 Depends on your preference? Why don't you try both?


----------



## avexdevil

Quote: 





aspenx said:


> Quote:
> 
> 
> 
> ...


 
   
  i would but i don't have the funds to get both at the moment, not to mention my complete lack of experience in amp modding even though it's just plug and play.
  anyway i've responded on the mstage thread too. though i wish i could try out the amp before getting it shipped all the way from china, seems like this mstage/lovely cube gets hardly any mention here in Singapore.


----------



## francisdemarte

I'll suggest you get the OPA627 if you don't have experience modding. It's a very well regarded opamp and is much less to worry about than the somewhat complicated and large discrete opa Earth.


----------



## aspenx

Quote: 





avexdevil said:


> Quote:
> 
> 
> 
> ...


 


 I'm from Singapore. If you're talking about the amp not being mentioned much on Jaben's forums, I guess I can't help cos I don't frequent it.
   
  And what Francis has mentioned, the OPA627AU is cheap if you get it through Stephen or JTam really. I don't like it though.


----------



## avexdevil

Quote: 





aspenx said:


> Quote:
> 
> 
> 
> ...


 

 yea no proper discussion on the m-stage/lovely cube or any for sale over on jaben, vr-zone and hwz.
   
  if you dislike the 627's, what opamp are you using then? i see you have an athw1000, which could explain why you feel the opa627 don't synergise as well as say the hd650 or k701?
   
  is your m-stage/lovely cube open for auditioning xD?


----------



## aspenx

HD650 and K701 AFAIK are very different headphones that shouldn't really be mentioned in the same sentence.
   
  What I have is the W1000X (more bass than W1000). I like my sound to be bright and more neutral than warm, hence my dislike of the OPA627. I'm using the LT1364 right now which gives me much better PRaT and bass extension.
   
  Auditioning? Hmm... Send me a PM if you're really interested I guess.


----------



## francisdemarte

Wanted to add on that I also own the W1000X and the HD650.
   
  Initially, I found the W1000X rather too bright and slightly simbilant. I feel the OPA627AU tames the top end well and adds a little warmth to the mids. But in contrast to aspenx, I like my sound a bit warmer than I do bright. I also like that the OPA627AU also doesn't muddy the HD650 which is already very warm.
   
  So I guess it all depends on your tastes.


----------



## francisdemarte

First page of this thread updated with recent changes/developments.


----------



## avexdevil

hey francis, i believe i have similar sonic preferences as you do. i own a m50 too, and everytime i listen to a track on my m50 (especially rock/pop), and swap around to my k701, the music seems to feel more laidback and incredibly cold in comparison. I understand these are 2 different pair of cans altogether, but I like how my m50s seem to add warmth and musicality to the vocals more so than my k701s. The OPA627AU + K701 seems like a combo made in audio heaven for me then .
  Quote: 





francisdemarte said:


> Wanted to add on that I also own the W1000X and the HD650.
> 
> Initially, I found the W1000X rather too bright and slightly simbilant. I feel the OPA627AU tames the top end well and adds a little warmth to the mids. But in contrast to aspenx, I like my sound a bit warmer than I do bright. I also like that the OPA627AU also doesn't muddy the HD650 which is already very warm.
> 
> So I guess it all depends on your tastes.


----------



## DaEMoNteNTAcLe

ditched lme49860, replaced with lme49720, biased with 6.2k resistors.
  end up i found the amp bright on opa627 and lme49860, both seems to have a shimmer at the upper end, really irritates my ears.
   
  will try using different cable from toroids to amp board later, using the same signal cable (white) used by stephen on just the ground connection (toroid to amp) gave slightly cleaner imaging.
   
  i believe i'll be on this setup for a long time..


----------



## aspenx

avexdevil said:


> hey francis, i believe i have similar sonic preferences as you do. i own a m50 too, and everytime i listen to a track on my m50 (especially rock/pop), and swap around to my k701, the music seems to feel more laidback and incredibly cold in comparison. I understand these are 2 different pair of cans altogether, but I like how my m50s seem to add warmth and musicality to the vocals more so than my k701s. The OPA627AU + K701 seems like a combo made in audio heaven for me then .
> Quote:
> 
> 
> ...




If you like your M50s, you'd like the W1000X. 

I've never heard the K701 personally to comment.


----------



## stau

hi
  I have ordered the OPA2111 am  for "lovely"

 later, I write as it sounds
   
  ciao
   
  edit
   
   
  I have ordered from Stephen


----------



## aspenx

stau said:


> hi
> I have ordered the OPA2111 am  for "lovely"
> 
> later, I write as it sounds
> ...




Stephen has already ran out of stock for the opamp. :blink:

Anyways, I've ordered mine too. I can't wait.


----------



## T.IIZUKA

Me too !
	

	
	
		
		

		
			




  
  Quote: 





aspenx said:


> Quote:
> 
> 
> 
> ...


----------



## francisdemarte

So many opamps, so little time!


----------



## T.IIZUKA

Quote: 





francisdemarte said:


> So many opamps, so little time!


 

  
   
  Lovely's Christmas gift.


----------



## lyramax

So, what is the verdict on the OPA2111AM, compared to, say, the OPA627?


----------



## stau

I'm waiting for OPA
 I have not yet


----------



## T.IIZUKA

Arrived!
   
  OPA2111AM(Made in U.K.) from Hong Kong.
   

   
   
   
  OPA2111KP + 3.49mA Bias Socket  changed to OPA2111AM.
    
  Started to burn.
  OPA2111 guess the soundscape, a sound resolution.


----------



## francisdemarte

Wow looks very nice! Let us know how it sounds compared to the OPA627!


----------



## T.IIZUKA

Listening to music since then.
   
  The richness of the bass, OPA627AU.
  Both the resolution is good.
  I think the sound stage is better OPA2111AM.
   
  A continued change and I think burn-in.


----------



## lyramax

Is the OPA2111AM noticeably better than its KP version?


----------



## T.IIZUKA

Quote: 





lyramax said:


> Is the OPA2111AM noticeably better than its KP version?


 

  
  Specs are different than in the KP and AM.
  AM is better on the numerical value of specs. 
   
  http://focus.tij.co.jp/jp/lit/ds/symlink/opa2111.pdf


----------



## lyramax

I meant "noticeably better" -- sound-quality wise.


----------



## T.IIZUKA

Quote: 





lyramax said:


> I meant "noticeably better" -- sound-quality wise.


 


   
  It is both the performance and the sound quality of OPAMP.


----------



## stau

and I'm still waiting for OPA2111am
 

 -  is Bass better in OPA2111 am  or  bass is in OPA267  better  ??????


----------



## aspenx

t.iizuka said:


> Listening to music since then.
> 
> The richness of the bass, OPA627AU.
> Both the resolution is good.
> ...




Sorry, I don't understand. Do you mean that the richness of the bass region is better with the OPA627AU? Is the soundstage of the OPA2111AM better than OPA627AU in your opinion?

Needless to say, I'm still waiting for my opamp...


----------



## T.IIZUKA

Quote: 





aspenx said:


> Sorry, I don't understand. Do you mean that the richness of the bass region is better with the OPA627AU? Is the soundstage of the OPA2111AM better than OPA627AU in your opinion?
> 
> Needless to say, I'm still waiting for my opamp...


 
   
   
  I am not accustomed to writing the sound in English. 
  What worrying adjective do I only have to use?
   I should have studied harder in school. (too late....)
   
   My impression is like this, Now.   (Results in Lovely Cube. No Bias Socket)
   

   Sound Stage (音場) is OPA2111 > OPA627 >= OPA2107
  Bass Ritch（低音の濃さ） is OPA627 > OPA2107 > OPA2111


----------



## T.IIZUKA

Quote: 





stau said:


> and I'm still waiting for OPA2111am
> 
> 
> -  is Bass better in OPA2111 am  or  bass is in OPA267  better  ??????


 

 a matter of personal preference.


----------



## DAi from TOKYO

Hello people 
   
  Thanks to T.IIZUKA's detailed explanation on his weblog,
  I was pushed to order the one too! (Arigato Gozaimsu!!)
   
  I'd like to use lovely cube for music production and listening purpose too.
   
  My DAC / Audio out to the cube is Apogee Ensemble(Via a Mac).
  I use HD650, K240 mkii, SRH840, Klipsch Image X10, and so on...
   
  I was in between m-stage, D100, etc first..
  I heard Lovely Cube is better than m-stage in quality,
  and original Lehmann BCL is neutral and clear enough for music production purpose too,
  so lovely cube it is! this time.
   
  According to Mr.Stephen the lovely box guy,
  it sounds neutral even when using the stock OPA 2134, its not high grade but true and real.
  I was recommended to go for OPA2111AM(UK) besides 627 MOD PACK for music production.
   
  according to him,
  OPA627 has warm tube sound (good performance in mid range vocal sound).  
  OPA2111 has greater stretch in High and low range and the sound image is clear.
   
  When burn-in finished and Im ready, I will write reviews and comparison to Apogee ensemble's headphone outs.
   
  (well, ensemble was not cheap, so I dont think its headphone outs are poor but
   I have to turn the knob almost to MAX when I listen to quiet classical music source,
  so I thought I would need a headphone amp to drive high-impedence phones well)
   
  last but not least, can you change the dip on the back of the box just like the original Lehmann BCL?
  And also though I asked Mr.Stephen on email a few mins ago, is that danger to set the different gains on each outs?
  (for the situation like I put 2 phones into each plug, and each has different impedence - high and low)


----------



## T.IIZUKA

Hi Dai,
  Head-Fi Enjoy.
  Thanks for the detailed review.
	

	
	
		
		

		
		
	


	




  
   
  >>OPA2111 has greater stretch in High and low range and the sound image is clear.
   
   
  I agree.
  And a wide soundstage.
   
   
   Please try by all means read the schematic.
  Independent output resistance. The possibility is high?


----------



## aspenx

dai from tokyo said:


> And also though I asked Mr.Stephen on email a few mins ago, is that danger to set the different gains on each outs?
> (for the situation like I put 2 phones into each plug, and each has different impedence - high and low)




There is no danger. In fact, you can even get a different sound signature from each channel if you want.


----------



## JiggaD369

Hey guys,
   
  Great thread on a nice looking amp. But I need help/advice from you LC owners!
   
  I have a a pair of Sextetts and decent balanced studio quality DAC (Kramer 6410N) coming in. It's nothing special but will get me into better sound territory (compared to M-Audio FastTrack Pro). I'm planning on recabling the Sextetts soon and rewire it to be balanced capable for future use, just incase. I'm not expecting the Kramer DAC to be very good soI don't plan on keeping the it for long and will upgrade it to another DAC next year.
   
  I'm not a DIYer and I feel comfortable enough to hook up a single ended LC but I see that the balanced version requires some mods (such as removing the Alps knobs and removing the headphone jacks). How much harder would it be to set up a balanced LC?
   
  I know I can always order another board later but then the fact that the LC boards use different type of parts due to availability worries me.
   
  What do you guys recommend I do? 
   
  Is a FULL balanced setup really worth it? I don't mind upgrading to a good balanced DAC since the Sextetts will be balanced-capable anyways.
   
  Should I look into getting two board and transformers or single ended LC?


----------



## stau

hi

  I test just three days opa2111(AM)  with lovely cube + hifiman HE5 + NAD 320

 that's my opinion

 scala max . - xxx

  ............... Bass              Stage / width          Jazz            Pop         Classik           hiphop             

  OPA2134   x                   xx                           xx                x           xxx                  x 

  OPA627     xx                 x                             xxx               xx          xx                   xx

  OPA2111    xx                xxx                          xx                 xxx        xx                  xxx


 --------


 opa2111(am) like very much
  thanks Stephen !


 ciao


----------



## aspenx

jiggad369 said:


> What do you guys recommend I do?
> 
> Is a FULL balanced setup really worth it? I don't mind upgrading to a good balanced DAC since the Sextetts will be balanced-capable anyways.
> 
> Should I look into getting two board and transformers or single ended LC?




I don't know if a balanced setup will be worth it for you or not, but I do know that there will be quite a bit of work to get a balanced LC to work nicely.

As far as I know, Stephen does assemble amps for buyers who don't want to DIY. Maybe you could ask him to make a custom balanced LC for you? I have no idea whether it's feasible or not though.


----------



## aspenx

Okay, so I got my OPA2111AM(UK) today.

At first listen, it was not engaging at all compared to the sound I was used to from my LC with LT1364 and Class A bias.

But the suddenly wider soundstage was really nice. After some biasing and EQ'ing, the OPA2111AM is now my new favourite. 

A short review after 2 hours of listening...

Bass: OPA2134 < OPA627 << OPA2111AM < LT1364

LT1364 still has the best bass bass to me. Accurate, deep and tight. The way I like it. The OPA627 is actually pretty disappointing compared to the OPA2111AM and LT1364 as it muddles the lower-mid regions too.

Trebles: OPA627 = OPA2134 < OPA2111AM < LT1364

LT1364 again.

Soundstage: OPA2134 << LT1364 < OPA627 < OPA2111AM

The OPA2111AM is just amazing...

Separation: OPA2134 < OPA627 < LT1364 << OPA2111AM

Once again, the OPA2111AM pulls itself ahead of the competition. I find the LT1364 and OPA627 more engaging than the OPA2111AM but I still like it best overall. It's not fatiguing at all. I love it!


----------



## stau

joooo

 because we are almost an opinion 

 1 ...... LT1364 I do not know  bass is good? hm
 2 ..... opa267 I'm disappointed
  3 ..... opa2111 my favorites bass oki  Treblle OK  stage OK  or just great

 sometimes I think that the stage / width is too wide and in opa2111am
 opa2111 is not as precise as OPA2134

 Today the best opa2111AM!!


----------



## DaEMoNteNTAcLe

just got my lt1361 today, couldnt find 1363 or 1364..
  but.. its kinda promising.. not as weighty on the bass as a bb2604 + 3ma bias.. but the mids r nice, and it sounds a wee bit cleaner than 627.
  627 probably have better extension.. i dunno.. i've been playing around with the power cable connector and mixing the solder on my board..
  im a bit closer to where i want, but still not satisfied.
  one problem i have is that i found this amp to be dry on the mids.. not sure whether its always that way or my tweakin gone wrong.
  any ideas on what i can do to make it more lush, wet, or smoother on the mids?


----------



## aspenx

I'm hearing plenty more extension with LT1364 than OPA627 on my system. I also like how the bass is not "overwhelming".

I find the mids a little dry too with some music. Maybe try a bigger film cap than the original 0.022uF ones? I don't know... Hmmm......


----------



## DaEMoNteNTAcLe

actually..
  after givin it about 100hr, the sound is quite good, extension is plenty. it is now totally preferable un-biased as of now, above all other opamp i have. hopefully will be gettin earth hdam later today and compare it out.
  but as of now, i'm already satisfied (finally?) with the amp. 
   
  next step would probably be direct solder the lt1361 on the board. im still thinking about it tho.


----------



## dxps26

Got the Amp from Stephen - Everything was all right for the first week or two, But today, the Power LED has started Flickering -  the two amber LED's inside the Amp are stable, but the power LED is going crazy - checked power connections, those seem okay too. Just Emailed Stephen about the issue, let's see what he has to say--otherwise the amp is working perfectly, a little ground hum when I touch the knob, but disappears when I short it by touching the body of the amp.
   
  EDIT - Stephen emailed back within the Hour. Sounds like a Bad LED. He very kindly offered to ship me a replacement LED - very reassuring to have that sort of Support. Kudos!!


----------



## francisdemarte

I had the same problem in my self built amp. Seems the Alps Blue is notoriously hard to ground. I solved by hum issue by putting another ground on the amp.
   
  Loosen on of the screws on the back of the amp and wrap a bare wire around it, hold the wire on by re-tightening the screw. Attach the other end of the wire somewhere on the case.
   
  See the instruction from the PIMETA amp: http://tangentsoft.net/audio/pimeta/steps.html


----------



## dxps26

Stephen recently updated his site with details on how to ground the ALPS pot. He was kind enough to mail me the links posted below -
   
http://www.alicemagicbox.com/lasercollection/lovelycubevrgrounding.html



http://www.alicemagicbox.com/lasercollection/lovelycube.html#05
    
  I think at the price paid for this excellent amplifier, this level of service and commitment is brilliant. Of course, many of us are experienced enough to work out small issues on our own, but then first-timers will be permanently turned away from the fun of DIY. A supplier as responsive as Stephen is what the DIY party needs to grow.
   
  Edit - Stephen mailed me again - there is an easy fix for those of us who find the Front LED too Bright - I shall Quote the mail Verbatim below -
   
  Quote: 





> About the LED, I agree with you some people want the LED not too bright. Last month I received an order and the buyer request to dim the LED.  I change the resistor that series with LED from 15K to 27K , and use sandpaper to sand the head of LED in order to diffuse the light.  The result is very good and that buyer likes the effect very much.


----------



## taiyoyuden

Has anyone compared this with the actual BCL yet? I saw it compared to the Matrix but not BCL yet. Also is it really an exact clone? The photos of the board look different. Is the toroidal the same?


----------



## T.IIZUKA

Quote: 





taiyoyuden said:


> Has anyone compared this with the actual BCL yet? I saw it compared to the Matrix but not BCL yet. Also is it really an exact clone? The photos of the board look different. Is the toroidal the same?


 

  
  I know people in Japan were compared.
  Similar in appearance. Just like the rear panel. A much indistinguishable. 
  He was saying the same sound. (OPA2134 in)
  Lovely Cube OPAMP interchangeable. This has the advantage.
   
   
  Toroidal transformer can be changed because there is a rank equivalent. (115V in case)
  The circuit is almost identical. (Which seems to be some differences)
  Lovely Cube is part of the same BCL, which is used or something higher.
   
  Please check to see the parts list.
http://www.alicemagicbox.com/lasercollection/lovelycube.html#02
http://www.alicemagicbox.com/lasercollection/talema30va.html
   
   
  BCL

   
  Lovely Cube
  with *Talema 25VA* Toroidal 

   
  Lovely Cube with *Talema 30VA *Toroidal.
http://www.alicemagicbox.com/lasercollection/talema30va.html
   
  Mine. 

   

   
   
  MATRIX m-stage


----------



## Cya|\|

The lovely cube has much better components. Especially if you mod it.


----------



## purrin

Quote: 





cya|\| said:


> The lovely cube has much better components.


 

 LOL "much" may be an overstatement. All use decent caps, none uses boutique. The LC depending on what's actually used maybe has an edge in the 470uF caps and the small input bypass caps for DC blocking. The other small caps are a wash (Siemens / ERO ~ WIMA / Philips.) The LC uses better resistors, particularly if they are the mil-spec variety which I think they are. Matrix has the best rectifier setup arrangement, but LC / BCL give you more options to tweak this section. BCL transformer is not encapsulated < Matrix / LC. BCL uses German sourced parts as much as possible for obvious reasons.
   
  Quote: 





cya|\| said:


> Especially if you mod it.





   
  Anything would have much better components (or at least I would hope so) after you mod it. 
	

	
	
		
		

		
			





 LC does however come at better price if you don't mind assembling, so it's more cost effective for those who wish to more seriously modify it. Obviously the BCL is a poor value.
   
  None of them has enough room to contemplate doing seriously re-constructive stuff to it.
   
  I never thought about it before, but I feel bad for Norbert. There would be a serious lawsuit if these clones were sold by retailers in the West where intellectual property rights are stronger and actually enforced. Everything is just _a bit_ too similar to the original.


----------



## VictoriaGuy

Quote: 





purrin said:


> LC does however come at better price if you don't mind assembling,


 

 It's a good value (IMO) even if you pay for the fully-assembled version. I  would have preferred to buy a Lehmann  BCL but the price differential was just too much.
   
  Of course, there's nothing preventing those of us with guilty consciences from sending some money to the designer as a form of 'royalty'.
   
  John


----------



## Cya|\|

Quote: 





purrin said:


> Quote:
> 
> 
> 
> ...


 


  The guy can sell it already modded. I do not have the skills, and I paid less than 200 euros to get a thoroughly modded one, with stepped pot, 627 opa instead of the cheap sounding default one, and with bias mod.


----------



## aspenx

cya|\| said:


> Quote: Originally Posted by *Cya|\|* /img/forum/go_quote.gif
> 
> The guy can sell it already modded. I do not have the skills, and I paid less than 200 euros to get a thoroughly modded one, with stepped pot, 627 opa instead of the cheap sounding default one, and with bias mod.
> 
> ...


----------



## Cya|\|

Quote: 





aspenx said:


> Quote:
> 
> 
> 
> ...


 
   
  Ok, but I'm just talking in terms of final sound.
 If these  things do not make it much better than the original, then you have to buy a totally different amp (like a phoenix or beta for instance) if you really want something more.


----------



## purrin

Quote: 





victoriaguy said:


> Of course, there's nothing preventing those of us with guilty consciences from sending some money to the designer as a form of 'royalty'.
> 
> John


 

 Actually, I'm probably going to do that with the proceeds of the M-Stage I just sold.


----------



## JiggaD369

My baby is on it's way..


----------



## Cya|\|

Good thing, you're the first person over me I see getting the amp with a stepped pot. Only 10 $ for a noticeable change.


----------



## francisdemarte

Let us know how the stepped attenuator performs!


----------



## lyramax

What are the op amps that work well on the LC and are best for music listening, mostly vocal/small ensemble jazz and folks music?


----------



## JiggaD369

Quote: 





cya|\| said:


> Good thing, you're the first person over me I see getting the amp with a stepped pot. Only 10 $ for a noticeable change.


 

 Yeah, I went for the whole nine yards! Ended up being $250 total (copper RCAs, 30VA Czech Transformer, stepped atten.) along with a 2111KP opamp.
   
  Should pair well with my Kramer DAC.
  
  Quote: 





francisdemarte said:


> Let us know how the stepped attenuator performs!


 

 To tell you the truth, this is my first "true" amp. SO I will let you know how the amp sounds as whole but from what I've read, a extra $10 makes a difference.


----------



## sunneebear

I've tried the Alps and Noble stepped pots before but never liked that I usually listen to what's in between the steps. SQ was not really noticable. I guess you need to use the DACT type with the array of resistors to hear a big difference.


----------



## Cya|\|

Quote: 





sunneebear said:


> I've tried the Alps and Noble stepped pots before but never liked that I usually listen to what's in between the steps. SQ was not really noticable. I guess you need to use the DACT type with the array of resistors to hear a big difference.


 


  Come on dude. In hifi people spend thousands of dollars, often to get little improvement. Here you just spend 10 dollar, why would people really think whether they should spend 10 more dollars or not?
  In hifi, people are too extreme. Some spend too much, some are happy when they spare 10 dollars because they get a normal pot instead of a stepped one.


----------



## sunneebear

I know what you mean but isn't this an act of faith?  Unless you buy the stock pot then latter swap it out for the stepped pot then you will never know how much of an improvement you got for that $10.   I don't have any boutique parts on any of my gear.  I cannot justify the price vs. SQ.  My point earlier was not meant to put down the sound quality but the physical aspect of stepped pots.  I just did not like having to be stuck with the steps when you really want the volume somewhere in between.


----------



## Cya|\|

Quote: 





sunneebear said:


> I know what you mean but isn't this an act of faith?  Unless you buy the stock pot then latter swap it out for the stepped pot then you will never know how much of an improvement you got for that $10.   I don't have any boutique parts on any of my gear.  I cannot justify the price vs. SQ.  My point earlier was not meant to put down the sound quality but the physical aspect of stepped pots.  I just did not like having to be stuck with the steps when you really want the volume somewhere in between.


 


  Yes, the seller told he he did a/b comparison, and he could hear the stepped one better than the alps one. And I have faith. You also have to consider that other people did such a comparison (with other amps) and could notice an improvement over the normal one. The stepped is theorically better. Practically, the difference is minimal.
  Ok if you want a volume between. But each step has a 6db difference. It's not very much. I don't think one would REALLY want to get a 3db difference. In that case, I could use the digital control of winamp, as -3db digitally don't ruin the quality at all.


----------



## T.IIZUKA

I get LT1364CN8.
   
   
  OPAMP exchanged.
   

   
  LT1364CN8
  Bias Socket = No
  Gain = +10dB
  Headphone = Ultrasone Edition8
   
   
  My ears are accustomed to the sound of Burr-Brown.
  LT1364 is a very comfortable feel. 
	

	
	
		
		

		
		
	


	



   
  Very beautiful female vocals.


----------



## lyramax

Thanks, I plan to try out the LT1364.  How is its sound compared to that of the OPA2111AM?


----------



## T.IIZUKA

Quote: 





lyramax said:


> Thanks, I plan to try out the LT1364.  How is its sound compared to that of the OPA2111AM?


 


   
  Yes.
  Burr-Brown OPA627 and OPA2111, OPA2107 is a comparison.
   
  LT1364 also OPA2111AM the different representations of the sound stage.


----------



## Knusperfisch

Alright !
  Placed and payed my order for a Lovely Cube. Seems to be the best option for about 200 bucks, and the seller is quite friendly too^^
  Hopefully it'll arrive soon.


----------



## T.IIZUKA

Quote: 





knusperfisch said:


> Alright !
> Placed and payed my order for a Lovely Cube. Seems to be the best option for about 200 bucks, and the seller is quite friendly too^^
> Hopefully it'll arrive soon.


 
   

   
   
  Lovely Cube, ±15V power supply.
  High voltage, be fulfilled in all dimensions.
   
  High voltage part of the OPAMP is useless so be careful.
  ex. AD8620 ( ±13 V)


----------



## lyramax

Can a Current-Feedback Op Amp, like the LME49713 (http://www.national.com/pf/LM/LME49713.html#Overview), be used in the LC?


----------



## T.IIZUKA

Quote: 





lyramax said:


> Can a Current-Feedback Op Amp, like the LME49713 (http://www.national.com/pf/LM/LME49713.html#Overview), be used in the LC?


 

  
   
  LME49713
   >>Key Specification
  >>Power Supply Voltage Range ±5V to ±18V
   

  Voltage corresponds.
   
   Is the cavity number LME49713MA?
  When it is MA, it is *SOIC*. 
   

  LME49713 is a Products of a single channel. 
   There is a need converted into a dual channel. 
   
   For instance, this Products. 
   
  Browndog
   

   
  Single-to-dual Op-Amp Adapter (p/n 020302A)
http://cimarrontechnology.com/single-to-dualop-ampadapterpn020302.aspx



*or*
   
  SO8 to 8-pin DIP Adapter (p/n 970601A)  *x2*
http://cimarrontechnology.com/so8to8-pindipadapterpn970601-3.aspx
   
*plus*
   
  Single-to-dual Op-AMP Adapter - DIP version (p/n 021001)  *x1*
http://cimarrontechnology.com/single-to-dualop-ampadapter-dipversionpn021001.aspx
   


   
  Other products (mine)


----------



## Knusperfisch

Can anyone tell me how the LC with it's standart OPAMP performs with a HD650 ?
  I heard that the LC has a warm sound signature. Just wondering how it pairs with the already warm sounding HD650.


----------



## T.IIZUKA

I think that compatibility with acoustic is good of LT1364. 
  It felt odd in Electronica. 
   
  I felt the music (Vampire Weekend and Beirut, etc.) to which it often listened OPA2111 was better than LT1364. 
   

  Quote: 





knusperfisch said:


> Can anyone tell me how the LC with it's standart OPAMP performs with a HD650 ?
> I heard that the LC has a warm sound signature. Just wondering how it pairs with the already warm sounding HD650.


 
   
   
  I do not own HD650. 
  I think that I can make it to the sound of the favor by changing OPAMP.


----------



## stau

hi

 ask


 opa LT1364   just stuck in lovelycube 

 and finished  ?
   
  or ?
   
  thans


----------



## francisdemarte

Quote: 





knusperfisch said:


> Can anyone tell me how the LC with it's standart OPAMP performs with a HD650 ?
> I heard that the LC has a warm sound signature. Just wondering how it pairs with the already warm sounding HD650.


 

 I own the HD650 with the newer silver screen drivers and I think it sounds fine with the stock opamp. I'm using it with the warmer OPA650 and sometimes I think it's a little on the thick side sound wise with some modern bass-y pop music.


----------



## Knusperfisch

Glad to hear that. Thanks for letting me know.
  I think I'm gonna figure that out on my own anyway. And if I really don't like th esound I still have the option to switch to another opamp.


----------



## Knusperfisch

By the way: how long did you guys had to wait before your LCs (assembled) got shipped?
  I paid already 10 days ago and although he said it would just take 7 days until the unit will be shipped my LC wasn't until now. (got no tracking number yet)
  I mailed him about that issue but I got nothing back so far.
  Sorry for double posting.


----------



## VictoriaGuy

Quote: 





knusperfisch said:


> By the way: how long did you guys had to wait before your LCs (assembled) got shipped?
> I paid already 10 days ago and although he said it would just take 7 days until the unit will be shipped my LC wasn't until now. (got no tracking number yet)
> I mailed him about that issue but I got nothing back so far.
> Sorry for double posting.


 
   
  As I recall, it took about 4 weeks from payment to get the parcel at my door in Canada. Fortunately, there weren't any delays in Customs here.
  Also, I think there is a Chinese holiday coming up, which could add further delays.
  John


----------



## Knusperfisch

Yea 4 days from payment to arrival at your door. But he didn't even shipped the parcel. He assured me that he's gonna send the parcel today but I neither received a tracking number nor a picture.


----------



## francisdemarte

My 2nd one was waiting on parts so it took longer than usual. Typically it takes about 2 weeks from HK to Chicago. Be aware that the Lunar New Year holiday is coming up and my delay your shipment. Shoot Stephen and email, he usually responds quickly.


----------



## lyramax

Quote: 





stau said:


> hi
> 
> ask
> 
> ...


 
  Of all op amps I've tried so far -- OPA2132, OPA2134, OP627AU, OPA2111KP, LT1364, LME49720HA, and LME49860 (all with 3.49 bias) -- I've come to like the LME49860 the best: very lush sound without loss of details.


----------



## Knusperfisch

Stephen told me that he's been sick which is why he couldn't make the way to the post office. But he also assured me that the unit will be shipped within 10 hours. And now indeed it is^^ Wow now thats what I'm calling service.


----------



## audiopc2000

Hi to all.
   
  Nice to meet you.
   
  I also bought an  assembled Lovely Cube standard configuration + stepped attenuator last week... I am in the sweet expectation....
   
  I read above that Stephen is sick. I wrote to him but I have not received further news from him...
   
  Knusperfisch do you have any news?
   
  Edgar Puglisi
  Maracaibo- Venezuela


----------



## Knusperfisch

You've got PM already. But again yes he told me that he's been sick. But I guess (well to be frankly I don't really know) that he's fit. And if you've been waiting longer than one week you should contact him, he answers really fast. (Well...its about 1 o' clock in H.K. now so he'll answer tomorrow)


----------



## DarkskyZ

OK, ordered mine today.
   
  I went for a fully assembled one with Talema 30VA Toroidal, stepped pot and Dual 627 Class A Bias MOD Pack (with Bias 3.49mA installed). I also asked for a dim blue power led  
	

	
	
		
		

		
			




  Now I have to wait and this is not the funniest part of the whole thing !
   
  I asked Stephen about his recommended settings for use with Grados (in fact Alessandro MS-1 at this time...), what would yours be regarding gain and opamp ?
   
  This will be my first amp and I need to be guided somewhat in the right direction.
   
  Thanks !
   
  -DarkskyZ


----------



## shrisha

Quote: 





darkskyz said:


> OK, ordered mine today.
> 
> I went for a fully assembled one with Talema 30VA Toroidal, stepped pot and Dual 627 Class A Bias MOD Pack (with Bias 3.49mA installed). I also asked for a dim blue power led
> 
> ...


 

 Sorry to be curious, but for how much total goes?


----------



## DarkskyZ

US$260 for the whole thing shipped to France.
   
  Stephen thinks about adding a logo to the faceplate. I might be the first one to get it


----------



## shrisha

Oh! Good price!


----------



## aspenx

darkskyz said:


> This will be my first amp and I need to be guided somewhat in the right direction.
> 
> Thanks !
> 
> -DarkskyZ




Be guided by your own ears. Seriously, there is no better way to make your own personal choice. Changing gains is definitely not difficult with the dip switches below. Neither should just simply swapping out opamps.


----------



## head-fidelity

Finished! The first tones come…
  Regards, Matthias


----------



## Knusperfisch

Congratulations!^^
  Looks pretty good.
  Now that you've done it, can you tell us how it sounds?


----------



## JiggaD369

Received mine yesterday!
   
  Burning it in right now but initial impression is money well spent!


----------



## BlaBlaBla

shrisha if you own Grados the best setting would be first below the highest - I think 18dB (second DIP switch ON, first OFF). I use that setting on SR 225. Maybe you will think that gain is too high, but it is not. OPA 627 likes high gain. (OPA 637 needs it.) I founded that bass is to weak for everything below 5. Stock OPA 3124 is just opposite.
   
  For ATH, I use 10dB (first ON, second OFF). They are easy to drive.
   
  - Because of regulator imbalance (LM317 = +14.8V and LM337 = -15.1) I had to use trimpot instead of 1.1K resistor. When the amplifier reaches operating temperature, DC offset is below 0.7mV. I lowered output voltage to +/- 14.2 V because this gives me the lowest DC offset, and I do not need big voltage swing for low impedance headphones.
  - replaced the stock BC-s (550 i 560) with BC109C and BC179C.
  - replaced Siemens/Epcos MKT input caps with ERO MKC 1862.
  - replaced stock ERO MKC bypass caps with ERO KP 1837.
  - replaced ELNA blue capacitors with Panasonic FM (same capacity).
  - replaced Nichicon imput caps (4700uF) with Mundorf Mlityc (same capacity)
  - replaced ADJ caps on LM317/337 with tantalum (10uF) for better load regulation
   
  Right now I am very satisfied. I owned Matrix M Stage six months ago, but this one is better. Especially if I compare DC offset that in M Stage was around 8mV, and in Lovely Cube it is below 1mV. Sound is more "in front" and less clinical, what I really like. It is pitty that there is no enough room for Cerafine because FM-s are sometimes too shrill and too rough. Cerafines are slow but sweeeeet... 
   
  Now I have plans to make another Lovely Cube... But with other rersistors (PRP, Mills/Kiwame, Takman), with new regulator (LT317A, LT337A) and rest will be the same (BC109/179, matched BD-s and ERO MKC/KP/polystyrene caps).


----------



## head-fidelity

I don't have yet much music belonged…
  altogether very highly detailed.
  For the old AKG K 340 the reinforcement is however nearly too small…


----------



## shrisha

Thanks so much for info BlaBlaBla! Cheers!


----------



## BlaBlaBla

Always welcome. And one big fact. Never save on transformer. Transformer has BIG influence on sound, especially if you are trying to run amp in A class. In that case, the bigger is always better. I think, for Lovely Cube, 25VA is minimum. Even 50VA is not to much. If transformer goes hot when you listening to music, that means that you have to replace it with bigger. Transformer must always have "a fair amount of reserves". Another Lovely Cube is in process of making. (Well, in the process of buying required parts...)


----------



## ringer

Quote: 





blablabla said:


> Always welcome. And one big fact. Never save on transformer. Transformer has BIG influence on sound, especially if you are trying to run amp in A class. In that case, the bigger is always better. I think, for Lovely Cube, 25VA is minimum. Even 50VA is not to much. If transformer goes hot when you listening to music, that means that you have to replace it with bigger. Transformer must always have "a fair amount of reserves". Another Lovely Cube is in process of making. (Well, in the process of buying required parts...)


 

  
  Why the same amp twice? Why not M3 for a change, or something else?


----------



## BlaBlaBla

With this amp I am totaly satisfied. (Right now.) Especially on Grado SR225. I am sure that there is a lot better amps on the market and in diy world...
  I like to stick with: "Keep it simple as possible, because you can save your money on quantity and spend on quality." (Buy two Takmans instead of 20 no name metal films, buy two ERO KP instead 20 ceramics, and so on...)
  M3 is not so simple, it has much more parts (with PSU). So, it costs a lot more...
   
  Excellent amplifier demands excellent source... Do I have flawless source at home? No. I don't. Do I listen to only uncompressed and FLAC music? No. I don't.
  So, having 50% better amp will cost me 150% more and will give me 2% better sound.


----------



## JiggaD369

For anyone looking to best the 627, you must try OPA2107AP. WOW! is all I can say.


----------



## evgark

Hi all, 
  I'm choosing between HLLY HIGH END SMK-III (where there are everything i want) and LC.
   
  If I buy LC,  what usb dac is better to buy for it? Almost all ebay and amazon DACs already have amps, it's a pity - i don't want to overpay for useless amp 
  It will be useful optical and coaxial input and usb2 support, and of cause enough sound quality for LC.
   
  May be something like that: 
  http://cgi.ebay.com/New-Hifi-USB-Sound-Card-w-Digital-Output-Monitor01-USD-/270696739823?pt=LH_DefaultDomain_0&hash=item3f06c873ef
  ?
   
  Please advise me.


----------



## BlaBlaBla

evgark  
   
  Most of DAC-s have an amp. But those amps always have weak spots. For example Matrix Mini I is enough good DAC but amp is slightly week. I don't say that it doesn't have resolution and dynamics. No. It just doesn't have power and energy to show full potential of headphones. Even for low impedance headphones.
   
  Separate DAC and AMP is good choice, but here we have another problem. Synergy. All DACs listed below are good enough for "driving" your LC. But you can't know if there will be good synergy between them. And you can't know which combination will suit you best. I tried few DACs and amps before I made conclusion. For example, E-MU 0404 is sterile, flat and boring, I think best for studio. Dr. DAC has sick resolution and aggressive interpretation and in many occasions listener starts to think about mistakes and bad recording and not about music. Matrix Mini I has the least resolution from those two before, and it is far from "technically excellent" DAC, but it is beautiful for listening because of warm, emotional and fluid interpretation. It shows you music, not the studio failures. Someone needs something else....
   
  Look for this...
   
http://cgi.ebay.com/CSG-STRAIGHT-USB-DAC-RCA-LINE-OUTS-based-PCM2702-/180519936280?pt=LH_DefaultDomain_0&hash=item2a07d3a118
   
  Or this...
   
http://cgi.ebay.com/AUNE-Nano-Top-quality-PCM2707-USB-DAC-Nice-Mini-DAC-/180562180223?pt=LH_DefaultDomain_0&hash=item2a0a58387f
   
  Or this...
   
http://cgi.ebay.com/Fubar-II-USB-DAC-Silver-Face-Plate-USB-Audio-/260724871787?pt=LH_DefaultDomain_2&hash=item3cb469d26b
   
  All this DACs will give you good results and run LC properly. All.
*The same topology* can be changed in many ways with small things... Resistors, capacitors, transistors... Even solder can give different signature... 
   
  Buy DAC, but amp - DIY.


----------



## evgark

*BlaBlaBla*
   
  Thanks for your comprehensive answer.
   
  Fubar II and CGS from your links have PCM2702, which supports only 16/44.1.
  Aune nano uses usb1 so i think there is the same situation.
   
  Is it useful to have 24 bit?
   
  I found this kit
  http://cgi.ebay.com/New-24-192-DAC-DA-CONVERTER-CS8416-CS8421-PCM1798-USB-/160518883450?pt=LH_DefaultDomain_0&hash=item255fabc87a
   it is rather expensive.
   
  Also there is 
  http://cgi.ebay.com/MOCHA-24-96-Stereo-DAC-USB-ster-digital-Sound-card-/120644872236?pt=LH_DefaultDomain_0&hash=item1c16fea82c#ht_2942wt_882
  but it hasn't optical input.


----------



## BlaBlaBla

I think that 24bit, over USB, does not have any sense. Most of USB ports on usual PCs do not have bandwidth for that. As far as I know, there is 44.1/16bit and 48/16bit. If you want 24bit (without problems) then you need optical, BNC or coaxial input.
   
  The best of all is optical input. It has no interference but it is very sensitive to way of handling.
   
  BNC and Coax inputs demad good shielded cable (interference). Good for rough handling.
   
  USB is less prone to interference than BNC and Coax, but it can pick noises from its own switch PSU unit (a lot of noises, cracks and other stuff - personally I do not like that).
   
  If you transport signal shortdistances and do not need 96kHz (only CD recordings), USB (44.1/16bit) will be sufficient for listening to music.
  If you need transport signals on short distances (but 96kHz, 24bit is a must), than shielded BNC/Coax.
  If you need transport signals on long distances (more than 5m, and it does not matter if it is 44.1 or 96kHz) optical audio cable is a must.
   
  I think, carefully built SATCH NOS DAC (44.1kHz/16bit) will destroy everything under 2000 USD (regardless 192kHz and 24bits). (subjective opinion)


----------



## T.IIZUKA

My system


----------



## evgark

*BlaBlaBla*
  Thank you.
   
  Quote: 





t.iizuka said:


> My system


 


  Splendid! And which headphone output on your diagramm do you like most of all?
   
  Added:
  Matrix mini-i also has headphone amp. Is there a great difference between it and Lovely Cube sound and musical quality?


----------



## BlaBlaBla

*T.IIZUKA*
   
  What is the difference between ATH AD2000 and ATH AD900? (sound stage, bass, mids, highs, clarity...)
   
  Thanks


----------



## T.IIZUKA

Hi evgark,
   
   
  My favorite combination, GRADO and Tokyo-Sound Valve-X.
  I have owned headphones GRADO HF-2, MS-2, MS-1, SR80 ...
  http://www.head-fi.org/forum/thread/438785/tokyo-sound-valve-x-se-tube-headphone-amp
    
  Currently, Lovely Cube and Edition8, AH-D5000 are used in combination.
  (OPAMP is a OPA2111AM)
  This combination "Vampire Weekend" has become a daily routine to listen to. 
	

	
	
		
		

		
			




   
   
   
  Hi BlaBlaBla,
   
   
  AD900 is for watching movies. (with JVC SU-DH1)
  It is a delicate than AD900 AD700. A lot of information.
  AD2000 is flat.
  http://www.head-fi.org/forum/thread/351231/ath-ad900-vs-ath-ad1000-vs-ath-ad2000


----------



## evgark

Hi T.IIZUKA, 
   
  Matrix mini-i also has headphone amp. Is there a great difference between it and Lovely Cube sound and musical quality?
   
  thanks.


----------



## T.IIZUKA

BlaBlaBla,
  You want the USB-DAC?
  USB-DAC is depending on the budget. 
   
   
   
  Quote:



evgark said:


> Matrix mini-i also has headphone amp. Is there a great difference between it and Lovely Cube sound and musical quality?


 
   
   
  I am not using the headphone out of MATRIX mini-i. 
  The output of Lovely Cube is good by several steps. 
   
  Lovely Cube >> MATRIX mini-i's HPA
   
   
  MATRIX mini-i is great as a *multi-input DAC*.
   
  I'm using MATRIX mini-i to "mod".
   HPA is not reworked.
   
  Please see this thread.
  http://www.head-fi.org/forum/thread/441960/matrix-mini-i-balanced-dac-hp-amp/600#post_7218464


----------



## BlaBlaBla

*New Matrix is out?!*
  I will wait 8-10 months to see upcoming reviews. Old Matrix Mini I was best buy, and hard to beat (for the price).
  A new one has difficult task. We will see... 
   
T.IIZUKA  
   
  Thanks for link!
   
 evgark do not think that Matrix Mini I does not have good headphone out. It has. And its headphone out is better than most PC sound cards on the market. Especially when stereo separation and musicality comes to play...... But...
   
  .... it is below LC.
   
   Changing capacitors is tricky work. I was changing capacitors in Matrix M Stage a lot. Tried Panasonic FC (deep, low but rounded), Panasonic FM (fast, wide and aggressive), Cerafines (warm, relaxed and emotional), Philips BC (dry, centered and hard), lower capacity of MUSE (king of female vocals and violins). In signal line I tried Vishay ERO MKC, ERO KP, Epcos MKT, Wima MKP, Philips Tin Foil, German Styroflex, Mylar, even old Russian K71-7.  All of them had good and bad points. The worst thing was when I replaced stock OPA with 2xOPA627. Then I had to try all again, because caps have bigger influence on sound when OPA627 was there. Sometimes more advanced and better classified capacitors can give you worse sound (Sound that you do not like.).Perfect combination, sometimes, involves caps with different signature. For example: big ERO MKC (warm, strong and centered) bypassed with German Styroflex (dynamic, relaxed and wide), or big WIMA MKP (deep and relaxed but bit fuzzy) bypassed with small ERO KP (open and excellent positioning), big Epcos MKT (dry, straight and bright) bypassed with small Mylar (liquid and emotional). It is all about trial and error... Until you find your "perfect combination". For your setup (source + DAC + cable + headphones)... )))
   
  What if you change headphones? Well... Start again... 
	

	
	
		
		

		
		
	


	



   
  What? I have not mentioned replacing and trying different resistors in a circuit, or even transistors???!!! Well...


----------



## evgark

*BlaBlaBla*
   
  Thank you for marvelous answer!


----------



## LeeC

Time to get one of this little cube


----------



## FlukeII

Hi francisdemarte,
  Laser Collection's clones are not bad, I compared their PCB with the original Lehmann Black Cube Linear PCB and you would think the PCB’s have come from the same Gerber (CAD) files.
  Two things though to watch with the clone, I was suspicious of the semiconductors shipped with the kit, we ended up replacing the diodes in the power supply with genuine PHILIPS (NXP) BYV27-200 as per the original, similarly, the LM337 and LM317 replaced with genuine NSC parts.
  (When I visited China last year there was a lot of talk in the industry of local backyard companies making inferior clone components and then trying to pass them off as genuine name brand parts - several large companies got stung buying nasty clone decoupling caps that cost a lot to recall product and rectify the situation....it's a real wild west there...)
   
  Again, replace the OPA2134 with the genuine thing from TI/BB. But the real catch is in the diamond buffer output stage: The clone comes with BC560 and BC550, replacing these with Fairchild’s BC560C and BC550C (hFE selection: C) and then replacing the output transistors also with FAIRCHILD BD139-16 and BD140-16 (hFE Selection: Group 16) this amp really comes to life!!! (The current gain of the transistors hFE is important here and what makes the difference between the Lehmann and the clone knock-off's from an audio point of view)
   
  The original Lehmann uses these high beta devices in the output stage - I wouldn't be surprised at all if they hand S.O.T. these parts before they stick them in the PCB: When you look at the genuine Lehmann PCB, the passive components, diodes and regulators look as though they've been wave soldered (e.g. Machine Soldered) while the BD139/140s and especially the BC550C/560C look as if they've been hand soldered - tell tail signs these parts have been Selected on Test (S.O.T.) before being mounted on the PCB, or they were faulty and the board was re-worked - doubt it some how! After all they're Germans, and it's inherent in their culture to measure and calculate everything! No doubt Lehmann will be matching for beta and may be VBE in the NPN and PNP driver stage in each channel - matching NPN and PNP devices is time consuming and expensive, especially with German labour rates...Or, as they sit so high off the PCB, it's just too hard to support them during Wave Soldering - this is going to be one of those unknowns...they'll probably read this and then proclaim that they measure eveything...
   
  (If you can get the original PHILIPS (NXP) versions of the BD139-16 and BD140-16 – this amp kicks arse. PHILIPS produced a superior fT rating of better than 150MHz (the ones I have measure better than the data sheet: ft=150MHz for the NPN and ft=220MHz for the PNP!!!) compared to around 50MHz for the ST parts –haven’t bothered to measure the ON SEMI parts; for some reason, probably embarrassed, neither ST nor FAIRCHILD will disclose the fT switching characteristics, we ended up measuring it on a test rig at work – things you do on a Friday afternoon waiting for the weekend!
  Also, the PHILIPS BD139-16 and BD140-16 seem to have hFE that measure on the high side and are very consistent amongst a production batch, so it is easier to get the left and right channels matched)
  ( I don’t know why NXP killed the BD139 and BD140 product line – unbeknown only to a bloody Dutchman! Their BC550C and BC560C were the best in the industry! The beta variation in batches of these devices was so small you could stick them into a differential stage of an amp without a care in the world as to their beta variation; on the other hand IMO On Semi devices are a nightmare – you have to measure every part for hFE and VBE variation to find two that come close (2%) when using them for a differential pair stage, but they are cheap, price wise! )
   
   
  We didn’t trust the input caps supplied with the clone kit either, 1,5uF Polyester and not sure about the 22nF. We ended putting in 1,5uF EPCOS Metallised PP B32654 and the BC KP462 (2222 462 .....) Polypropylene 22nF and things really got better.
   
  Also the 100pF (correction) cap across the non-inverting inputs of the OPAMP needs to be replaced with the genuine McCoy BC KP464 (2222 464 .....) F 630V PP 100pF.
  Lastly, we replaced the 4.700uF Electrolytics with genuine NICHICON parts from MOUSER, actually the FM Series PANASONIC turned out to be a better bet.
   
  IMO: The biggest issue with the knock-off’s from CHINA, such as the Lovely Cube, is that the people doing the cloning don’t pay enough attention to the subtleties in component selection used in the original circuit / product– they tend to build the stuff with whatever they can get their hands on without any real thought to the quality of what they are producing – shame really!
   
  Either way, I could never afford to buy the genuine Lehmann - just too pricy by the time it gets down to NZ! I saw it in a shop locally, listened to it and thought nice sound, but no way was it worth the money they were asking (NZD$1900) - I just had to walk away from it. When the kit came up on eBay I jumped at it.
   
  Then I got the chance to pull the lid off a friend's Lehmann and spotted all of the above...
   
  Stayed tuned for the next instalment...more to come,,,,


----------



## BlaBlaBla

I replaced all except BD-s, diodes and regulators. But not because I do not have confidence in LC seller but because I wanted to do something on my own.
  BD-s made by Philips is hard to find. BC-s even harder. Diodes are 3USD each. Input caps (Mundorf SI) are miles away from stock Nichicons but they also cost 3 times more. In Croatia it is equal which brand you use, because here we get stuff from China. Only way is to look abroad. I ordered something from Canada. Now I have to look for rest...
   
  In Lovely Cube I got Philips BD139 and BD140 (PH83 and PH87). In Matrix M Stage are ST DB139 and BD140. Philips is better (better gain).
   
  I can not say anything about BC-s because in Matrix M Stage is Philips BC550C/BC560C and in Lovely Cube I got something with Wxxx part number. I replaced that with BC109C (CSC) and BC179C (CDIL). And results are stunning. If you are lucky you will get Philips. If you are not, you can buy 20-30 parts BC-s and find the good one. (That is reason why I always have spare 109C/179C bought in a trusted store in Germany.)


----------



## francisdemarte

FlukeII:
   
  Thanks for the very detailed report of the LC components! What initially made you suspect of the power supply diodes?


----------



## BlaBlaBla

I think, you can not. At least without proper equipment. Instead of that it is better to invest in good coupling caps and good electrolytes before regulator.
   
  Well I want to explain something...
   
  Difference between XXX product and YYY product is only in quality control. You can buy 10 XXX caps, and all of them will last, for example, 6 years and in those 6 years will be within specifications (100% quality). You can buy 10 YYY caps and 4 of them will last 6 years (40%) within specification, 4 will last only 2 years (40%) within spec. and 2 will be out of specifications (which means BAD - 20%) right after production. *Only 40% are within specification*.
   
  Production (amount of products) is the same for XXX and for YYY. But XXX passes a lots of controls and its production is in constant upgrade and under supervision, and YYY has no quality control and everything what produces - sells on the market, and final users are people who represent "first quality control after production". XXX product is more expensive than YYY, for 5-10 times because more labor, and products that are returned back (recycled).
   
  But as we see, on the market is a lot of consumer parts that are replaced after year (because they became obsolete - good or bad it does not matter - cell phones, TV-s etc...)... Parts who will last 6 years are not needed anymore because they are replaced from user itself after 1 year. That means that those* 40% within spec. are now 80%*. And only one that are out of specification right after production are BAD (*20%*). And usual buyer will say:"Well, yes. Two caps were bad but, they were very cheap. I bought five more. At the end I am satisfied..." So YYY sells more than ever, and have bigger profit. XXX is struggling in a deficit, regards high quality, because such high quality is not needed anymore.
   
  It is not needed any more, because of *us*.
  Because of *our* demands for *new technology*. We buy new product every time when something comes out. We are buying because something is NEW, and not because it is QUALITY PRODUCT .
   
*Buyer is guilty*. Not the manufacturer.* WE are guilty*.
  It will happen, that people who want good parts, will have to disassemble 20 years old amplifiers, TVs, etc, and take parts from there.
   
  Cheers


----------



## FlukeII

Quote: 





francisdemarte said:


> FlukeII:
> 
> Thanks for the very detailed report of the LC components! What initially made you suspect of the power supply diodes?


 
  It wasn't so much the rectifier diodes on the board, it was the output transistors...the kit supplies black devices with the BD139 marking, PH and 91 presumably the counterfeiters idea of a date code...when I saw PH - only PHILIPS used to use this marking on it's on on TRIACs, SCRs and MOSFETs; with BJT's it always used to be PHxy - xy was the year - at least that's what i remember!
   
  The trouble is the PHILIPS BD139 and BD140 devices, to the best of my knowledge, were only fabed in the Nederland’s and Germany, then packaged in the Nederland’s and Belgium e.g. the silicon wafer was cut and the transistors glued to the Collector terminal and the molded SOT32 package applied.
   
  Having worked for PHILIPS at the time in 91 when we were using these parts, they only ever came in a light grey plastic housing with printed BD139 and the date code, say PH91 (yr 91), they were not using laser etching based markings until after the 90’s for devices and never on the BD139 and BD140s only made in EU. (Also, the factory would only do one production run per year and put excess into inventory - if you neded more, you had to wait to next year's production run - these were the days before the internet -- life was easy!!)
   
  (When the ELCOMA section was broken up within PHILIPS and they formed NXP, they kept the production of the BD140 and BD139 devices the same - according to the local distributor)
   
  So the dead give away was the packaging of these output transistors - they just don't look right.
   
  Attached is a photo of genuine PHILIPS devices, made in 1995 and 2001 of the BD139 and BD140 (I can’t show a photo of the BD139-16 or BD140-14 as the AMP is at a friends house and a I can’t find the last 10 pcs of each in the spare room – it’s a mess with boxes everywhere…)
   
  For the BD139-16 / BD140-16 the markings are identical except that there is the number 16 placed near the BD139/BD140 text, the same font size. e.g.BD139 16 or BD13916 - depending where the devices were packaged.
   
  That wasn't enough I thought, so at work we tested the fT and hFE of these parts (supplied with the Lovely Cube kit), and while close to the ST parts performance, they were nothing like the original PHILIPS parts, therefore they can only be counterfeit IMO?
   
  I suspect the kids putting these kits together were at primary school back in 91 when PHILIPS were making the BD139 and BD140s - so I suspect they have no idea what they are buying from their component suppliers, else they know exactly what they are doing and are too preoccupied chasing Deng Xiaopingi's vision: "...it's glorious to be rich..."!
   
  PS. I would be really amazed if the counterfeiters can clone the original PHILIPS / NXP packaging material (epoxy resin), at PHILIPS they used to make their own resins from raw materials - that's why I'm sure the black BD139s and BD140s supplied in the kit are fake....


----------



## BlaBlaBla

OMG... After this, I realize that 95% of electronic parts are not genuine. I remember the gray transistors. I think that last time, when I saw them, was in old Sabba TV (20 years old)! So if other parts are equally old (Toshiba) then we can expect nothing....
   
  Conclusion is: If someone is in the DIY bussiness, top priority is assembling amplifier that works properly (eg. does not make strange noises, hisses or blows headphones), and has parts that have passed basic quality control. We can forget about rest ("only genuine parts"). Only hope is to catch part that is within spec.
   
  I was worried until now, but too much concern about technical stuff can spoil the enjoyment in music, so:
  - headphones are working properly without cracks and hiss,
  - DC offset is below 3mV on both channels,
  - and amplifier is not overheating.
  - my ears are satisfied,
   
  Fair enough.


----------



## FlukeII

For the next installment, the Lovely Cube Kit comes with some electrolytics that don't look as though they are the original thing, the clues here are the quality of the shrink wrap labels around the capacitor's cans - it's possible they are genuine, but nonetheless I figured you could do better...
   
  For that matter, the copper pour of the Lovely Cube PCB doesn't look as heavy as the original Lehmann PCB, which looks as though it's using 2,0 oz copper. The  Lovely Cube PCB looks as though it's using 1,0 oz copper or less?
   
  For the main smoothing capacitors, the Lehmann Black Cube uses VISHAY / BC 4700uF 40V +105deg C, part number 058 57472, 30mm x 30mm case with a Ir(100Hz)=2,96A, 3,61A and Z(100Hz)=59m Ohm and 40m Ohm @ 10kHz.
  This part is not bad and is easily obtainable from the like of RS Components and Farnell.
   
  We thought about trying other capacitors in this position, but we found the biggest sonic signature change came with changing the 470uF 25V Electrolytics decoupling the op amp and the diamond buffer stages.
   
  The original Lehmann used 470uF 25V United Chemicon LXZ - this part seems to be LXZ25VB471M10X16LL, 10x16mm. The specs on this part are pretty good for a switchmode supply type application: Zmax(100kHz)=68m Ohm, and Ir(100kHz)=1,050A, but at audio frequencies (1kHz), you only get about 85%._UPDATE:  The LXZ caps have a different part number at Digi-Key, they stock the ELXZ250ELL471MJ16S 470uF 25V Part#: _565-1958-ND_, they say it is the same part but, different part number; no explanation why._
   
  Later I'll post up a table with a bunch of capacitors we tried, but to cut to the chase the best part that worked here for me was the PANASONIC FM Series (EEUFM1E821L) 820uF 25V _(Digi-Key: EEU-FM1E821LB-ND)_ - the issue is with the capacitors so close to the heatsinks you're limited to about 10mm diam. These were decoupled with 220nF EPCOS Stacked Film MKT capacitors B32520C224J - _(Mouser Part#: _871-B32520C224J) these had to be soldered underneath the PCB! These capacitors are in the output stages. This gave a fast tight presentation that wasn't in your face - mids not as warm as when using Nichicon PM Series - Extremely Low Impedance, High Reliability, 680uF 25V (UPM1E681MPD) _(Mouser Part# _647-UPM1E681MPD), but it's most pleasant when listening on my T1's, nice Bass on DT770's and fast with the AKG K271 MkII's.
   
  More to come...


----------



## ringer

Quote: 





flukeii said:


> We thought about trying other capacitors in this position, but we found the biggest sonic signature change came with changing the 470uF 25V Electrolytics decoupling the op amp and the diamond buffer stages.
> 
> The original Lehmann used 470uF 25V United Chemicon LXZ - this part seems to be LXZ25VB471M10X16LL, 10x16mm. The specs on this part are pretty good for a switchmode supply type application: Zmax(100kHz)=68m Ohm, and Ir(100kHz)=1,050A, but at audio frequencies (1kHz), you only get about 85%.


 
   
  What do you think about bipolar Mundorf E-cap 470uF?


----------



## BlaBlaBla

Is not 820uF too much?
  In the specification for LM317/337, they suggest that output cap is between 100uF and 1000uF. Two 820uF (per channel) are 1600uF.
  What about low impedance headphones? Do they need big caps on the output?


----------



## ringer

Quote: 





blablabla said:


> Is not 820uF too much?
> In the specification for LM317/337, they suggest that output cap is between 100uF and 1000uF. Two 820uF (per channel) are 1600uF.
> What about low impedance headphones? Do they need big caps on the output?


 

 In my first DIY I use 16000 uF in output of LM317. So I think 1600 uF is OK


----------



## Knusperfisch

Well I don't care if these parts are counterfeit products as long as the amp sounds good. I think the slogan "you get what you pay for" fits good in here. You should always consider that the seller wants to make profit, and you should also calculate that you could get fake parts especially if you're buying from China. But I really wonder why the Matrix M-Stage is considered to sound worse in comparison to LC. Does it mean that the M-Stage uses also counterfeit parts ?
  Maybe these transistors are just fake labeled if there on par with the STMicro BD139, BD140? Can't imagine that chinese fabs can produce transistors at STMicro quality which is definitaly not the worst in the industry.
  All I can say is that as long as the quality of the parts don't deceed a minimum level, sound good and live long I can live with ungenuine transistors. And if I want to upgrade I can still change them^^
  Does anybody tried the Infineon BD139, BD140 ?


----------



## ringer

I want to change 4700uF caps (that has dimansions 30x30 mm) on bigger caps 30x40 mm. Is it fit in Lovely Cube body?
   
  (Sory for my English. I have a little talking experience.)


----------



## francisdemarte

Quote: 





blablabla said:


> OMG... After this, I realize that 95% of electronic parts are not genuine. I remember the gray transistors. I think that last time, when I saw them, was in old Sabba TV (20 years old)! So if other parts are equally old (Toshiba) then we can expect nothing....
> 
> Conclusion is: If someone is in the DIY bussiness, top priority is assembling amplifier that works properly (eg. does not make strange noises, hisses or blows headphones), and has parts that have passed basic quality control. We can forget about rest ("only genuine parts"). Only hope is to catch part that is within spec.
> 
> ...


 

 BlaBlaBla has a great point. If amp works properly and sounds great why change anything? Just enjoy it.
   
  Those of us that insist on using genuine parts, name brand parts, Stephen sells the LC as an unpopulated board. You can hand select all the other parts from a trust worthy vendor and build it according to the parts list (or overbuild it) yourself. This is what makes the LC more attractive than the M-Stage for the technically inclined.


----------



## BlaBlaBla

Ringer, yes they will. For example Mundorf Mlytic SI/PI are 30x40mm. They fit in. After trying both of them, Mundorf eat Nichicon for starters.
   
  I was reading what Fliukell did, and because I really like to do experiments, and I can not help myself not to do that. 10 minutes ago I replaced Mundorf SI with stock Nichicon and right now I ask myself two things... First, where the low register has gone, second why I replaced good part with this crap (so the entire low register has gone). There is no punch, there is no grunt, everything is so mellow. Lower frequencies are so shy. When there is bass, it has less control. I mean, if you like mellow bass and huge sweetness - it is ok. But this is not for someone who like "stage in front of his face"...
   
  Probably that is reason why Mundorf cost 15 USD each, and Nichicons 6 USD each.
   
  Second tought. Do not use WIMA for coupling on output. You will think that someone is speaking from the bottom of his butt. They emphasize depth too much, and voices are artificial and metallic. With sibilance. Only if music is perfectly recorded, this setup will have benefits because richer space. Stock ERO is "in front", slightly flat, sometimes rough, warm, and has big separation from left to right (wide)... Good for old recordings. Even if it is not genuine...
   
  Now I have to re-solder those parts back.


----------



## BlaBlaBla

Re-soldered. Wima is out - ERO KP is back. Separation is, again, flawless.
   
  Probably, for three or four weeks it will arrive another Lovely Cube PCB.
  Also, I ordered PRP (signal), Takman (1W) and Kiwame (2W output) resistors (among with LT317/337 regulators) from Canada. When those parts arrive I will solder them on new LC PCB, and then I will be able to compare those two PCB-s (one with 50% stock parts - that I have right now, and LC that will only have stock Alps pot)...


----------



## ringer

Thank you. Already ordered Mundorf M-Lytic PI 63 VDC 10000 uF.


----------



## BlaBlaBla

ringer
   
*Not 10000uF 63V!*
*6800uF 63V is maximum. 10000uF 40V also fits.*
   
  But 10000uF 63V *does NOT!*
   
  I did not tell you exact dimensions that fit in a case.... 30x40mm is 4700uF 63V, 10000uF 63V is 35x50mm....
   
http://www.partsconnexion.com/capacitor_ele_mundorf_snapin.html
   
  Could you recall it, or change it for less? 4700uF is enough even for the most demanding headphones. Usually people say that 1A goes for every 2000uF max. 4700uF is enough for  2.2A on each channel. If you load output with 2A on each channel, you will probably burn LM317/337 before Mlytic falls down. They have sick discharging characteristic.


----------



## ringer

Quote: 





blablabla said:


> ringer
> 
> *Not 10000uF 63V!*
> *6800uF 63V is maximum. 10000uF 40V also fits.*
> ...


 

  
  This is strange. In this catalog http://www.mundorf.com/downloads/info-news/english/MUNDORF_Fidelity_Components_catalog.pdf they say that dimensions is 30x40mm.


----------



## BlaBlaBla

There is small problem. Mundorf M-Lytic has, actually, a few M-Lytics. "PI", "SI" and rest.
   
http://www.google.hr/imgres?imgurl=http://img.audiomania.ru/pics/goods/big/mundorf_m-lytic_pi_63_vdc_10000_uf1.jpg&imgrefurl=http://audio.i-mho.ru/category_65000000_page_11/&usg=__7uN-1p4Ts5rDSEQsUdVt2KyxiS8=&h=600&w=600&sz=173&hl=hr&start=0&sig2=qvnFXal6Bs6MAF_YrCE5DQ&zoom=1&tbnid=MAOu5veHvm7WDM:&tbnh=149&tbnw=134&ei=5-lFTaXUOIKxtAaYrdnuDQ&prev=/images%3Fq%3DM-lytic%2BPI%26um%3D1%26hl%3Dhr%26sa%3DG%26biw%3D1280%26bih%3D770%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=125&vpy=69&dur=1556&hovh=225&hovw=225&tx=97&ty=115&oei=5-lFTaXUOIKxtAaYrdnuDQ&esq=1&page=1&ndsp=24&ved=1t:429,r:0,s:0
  This one is "PI". 125°C.
   
   
http://www.hificollective.co.uk/components/mcap_mlytic_si.html
  This one is "SI". 85°C.
   
  Mine has "PI" mark on iself and is rated for 120°C. It is bigger than "SI" with equal capacitance and voltage. (Mine is 30x40mm) Problem is that, stores (usually) do not take care, because price is almost equal. But dimensions *are not*. So maybe you will get PI (10000uF, 63V is a real beast, and you will have to drill the enclosure to put it in) or you will have new version SI which is 1/3 smaler. And it will fit in, without problem.
   
  I bought Mundorf M-lytic in Germany (Banzai Music). They have good and fresh stuff (capacitors) but sometimes are very unprofessional and imprecise. Last month I had ordered BDs 139-16/140-16 for push-pull amp, and they sended me 139-16 and 140-10. They cost is same but I can not put them together in a balanced push-pull. (because different gain)
   
  Lesson learned - do not buy from Banzai Music if New Year is close, or in summer holidays. Student volunteers mess everything.


----------



## FlukeII

Quote: 





ringer said:


> What do you think about bipolar Mundorf E-cap 470uF?


 
   
  Hi ringer,
   
  Unfortunately I’ve never had the chance to try any of the Mundorf products; someone gave me some of those V-Cap OIMP series (Oil Impregnated Metallized Polypropylene) film capacitors, 4.7uF 250V when I was travelling through LA once.
   
  When I got them home, back in NZ, I stuck them in my Clone Beyerdynamic A1 and sat back and listened for a week. About two weeks later I put the EPCOS Polypropylenes, bypassed with original PHILIPS KP460 22nF Polypropylenes, back in and wondered what I had been listening too in the V-Cap. I came away really confused about what I should be getting from those V-Caps: IMO they seemed to cast their own veil over the music...
   
  I suspect the V-Caps work really well in Valve gear, especially SEPP Class A Triode and Tetrode based designs, awash with even order harmonics that do sound pleasing to the human ear – so I’m told. The problem I found with valve gear I had was that “everything” sounds sweet and warm…you get sick of it after a while…
   
  IMO, caps like the V-Caps assert their own timbre and character on the music, especially when you use them as AC coupling capacitors as I was.
  Also, I would be curious to know what the ESR, ESL and other parasitic characteristics are of the V-Cap, including the transfer function for the dielectric – I bet it’s non-linear, especially across the 0 axis.
  I found out latter that those V-Caps were about USD$90 each! I was really shocked at the price. IMO I can’t say that they were value for money or I would even consider them again….
   
  I gave them away to another friend and I heard he used them for a while in his own amp for a month and then pulled them out and switched back to using the PP Orange Drops bypassing and EPCOS MKP cap; he too was using a solid state amp design. He made similar comments to what I found...


----------



## FlukeII

Quote: 





blablabla said:


> Is not 820uF too much?
> In the specification for LM317/337, they suggest that output cap is between 100uF and 1000uF. Two 820uF (per channel) are 1600uF.
> What about low impedance headphones? Do they need big caps on the output?


 
  Hi BlaBlaBla,
   
  Don't get too concerned about overloading the LM317T/LM337T regulators in the amp, provided they are heatsinked adequately, they will go into current limiting mode, on switch-on, (Iinrush to the caps will be limited to about 1,5A to 3,4A (depending on device production spread) for the NSC LM317T, until the capacitors charge up, kind of a "soft start" function.
   
  In my amps I installed schottky diodes such as the 1N5819 across the +15V rail to ground and the -15V rail to ground, reverse biased; this measure will ensure that the supply rails are never reverse biased during power-up or if one of those caps fails and shorts; it protects the OPAMP primarily,
   
  The NSC LM317T regulator and it's negative counterpart, are pretty well protected thermally and seem to be able to take a real beating - I like them a lot, the only issue is that you need to make sure that you have a minimum load applied of at least 10mA (as per the data sheet) else they will goof you up in your circuit and can be a little unstable...other than that they are great. Also they like being decoupled well; see the Datasheet.
   
  On the Lovely Cube, I found bypassing the Adj pin with a 100uF 25V NICHICON PM Electrolytic in parallel with an EPCOS 470nF MKT (such as EPCOS B32529C474J) Stacked Film caps, they sound better IMO than just having the 150nF WIMAs - as per the original Lehmann design - you'll need to install a diode from the Adj Pin to the Vout Pin to avoid blowing them up when you turn off the amp -- see the National Data Sheet there's a lot of good info in there.
  This arrangement looks ugly with bits soldered underneath the PCB etc, but it sound's great IMO...


----------



## FlukeII

Quote: 





knusperfisch said:


> Well I don't care if these parts are counterfeit products as long as the amp sounds good. I think the slogan "you get what you pay for" fits good in here. You should always consider that the seller wants to make profit, and you should also calculate that you could get fake parts especially if you're buying from China. But I really wonder why the Matrix M-Stage is considered to sound worse in comparison to LC. Does it mean that the M-Stage uses also counterfeit parts ?
> Maybe these transistors are just fake labeled if there on par with the STMicro BD139, BD140? Can't imagine that chinese fabs can produce transistors at STMicro quality which is definitaly not the worst in the industry.
> All I can say is that as long as the quality of the parts don't deceed a minimum level, sound good and live long I can live with ungenuine transistors. And if I want to upgrade I can still change them^^
> Does anybody tried the Infineon BD139, BD140 ?


 

  Hi Knusperfisch,

   

  Fakes are important IMO: I once spent two weeks trying to figure out why a headphone amp that I was designing was unstable and then when I connected low impedance headphones (GRADO SR60s) would blow the output stage and then assert a DC offset on the output terminal and cooked both drivers – this really pissed me off. I spent ages screwing around with these fake devices until someone at work suggested that may be they were fake – that’s when the penny dropped…

   

  The amp used the fast and good HITACHI 2SD669A-D and 2SB649A-D, ft=140MHz, low Cob=14pF, and good Beta (Hfe) out to 150mA or so.

  During my hair pulling I even substituted inferior devices with the same Ic and Vce and the amp appeared to work fine, when I put the fake 2SD669A and 2SB649As in the circuit, it went crazy oscillating, bouncing around and then BANG when I loaded the output stage - no output stage and bad DC offset on the output.

   

  Recently someone I know quite well, was rubbishing how bad the BD139 and BD140 transistors were, he bought them off eBay – I gave him some of the PHILIPS devices and he couldn’t believe the difference he was hearing.

   

  So:

  1.     Fakes will always goof you up – you’ll spend ages pulling out your hair trying to figure out what’s wrong with your circuit; or it will blow up and burnout your precious headphones!

  2.     Fakes mean that you might unfairly criticize the performance of a part, as my friend did about the BD139 and BD140s.

  3.     Listening to Fakes might mean your missing out on true performance…

   

  Attached is a photo of the fake HITACHI’s I bought from some Chinese dude on eBay – I kept the 2SD669As but smashed the fake 2SB649As with a hammer...it felt good



   

  How did I know they were fakes? I got a friend in Tokyo to contact Renesas Electronics; When I emailed them I got ignored – probably because I didn’t write in Japanese!

  They came back and said: The markings are wrong, laser etching wasn’t used on this part, the silicon die is approximately 60% the correct size and mounted in the wrong location, and the HITACHI round logo is the wrong dimensions and shape, the packaging epoxy was wrong and the 2SD669A's were made with a green epoxy – gosh! All this from just looking at the part in a photo - it would have been good if they had been interested to test these fakes...


----------



## evgark

So, if Lovely Cube is full of fake parts, then other Chinese amps and DACs (eg. Audio-GD, Matrix, Hlly, Musiland etc.) contain them too. Otherwise, the sound quality between LC and them would be very different.
   
  I almost ready to buy components for the first step:
  usb -> Audio-GD NFB-12 ($200 promo) -> HD650 
   
  and then, second step, to buy Lovely Cube:
  usb -> Audio-GD NFB-12 ($200) -> LC (~$200) -> HD650
   
  After the second step Audio-GD NFB-12 will be used only as a DAC with dual WM8741 inside.
   
  Please criticize my choice )


----------



## BlaBlaBla

I have only low impedance headphones.  (Grado, ATH)  But...
   
  When I assemble (solder) something there is always FIRST test. In that test I use 5 USD headphones (IEMs usually) turn my assembled amp on and turn the pot to 12 o'clock. In that state I leave amplifier for 4 hours. After 4 hours, I check DC offset in loaded and unloaded state. I check temperature (with my finger - if I can hold for more than 10s it is below 60°C). After that I switch amplifier off and leave it for about half hour. Then I switch it on and check DC offset again. I also check noises through headphones (IEMs are good for that-very sensitive). It is good when I am able to hear noise that comes from transformer. That noise is equal trough entire range of amplification and it is not something to worry about. Besides, I like it. It reminds me on human nature. (Technical imperfection is equal to nature perfection.)
   
  If it blows IEM headphones that cost me 5 USD I do not care.
   
  After that test amplifier is ready to take ATH headphones. Then there is first listening that takes 1 hour. After 1 hour I check DC offset again. Every time when I replace capacitor or Opamp I check DC offset. That is the most important thing. DC signal (offset) will kill your headphones, not pure AC noise or AC oscillation. Or transformer hum. Because I tested it (15 hours) and DC offset is always below 3 mV, I have full trust in DIY LC.
   
  Be aware of DC offset in LC, because it will depend on your Opamp. (eg. in my setup OPA627 has 2.6mV on left and 0.3mV on right; OPA2107 (biased 3mA) has 2.3mV on each channel, OPA2134 has 4.2mV on left, 0.1mV on right) measured after 2 hours (warm amp).
   
  DC offset changes within temperature of your amp. When it is cold it shows (in my setup) 5mV on left and 4mV on right channel. After warming up offfset settles below 3mV.
   
  If something goes wrong accidentally (because unknown reason), and headphones blow off, well I can do nothing. )) In the same way, I can walk down the street and be killed because of careless truck driver ("because I was at the wrong time in wrong place"). ))
   
   
  I write long posts, because I want to improve my writing skills (english language)...


----------



## rayshader

We share in your predicament of buying fake hitachi items off ebay. Certainly it's been a nightmare. Should I be complaining i paid money for my cds and records while none of them sang live in front of me? To illustrate your experience with us here is far from edifying for the thread, especially no one is hinting for a cause of being cheated with the lovely cube. For some of us here who has placed good trust on the seller over the lovely cube. I doubt there is any complaints given the cost performance ratio. Surely its not engineered to be a BCL replacement or equivalent, it does however allows opamp switching with minimal fuss something the BCL can't. Common sense will dictate the similar overall design accounts for the common traits between the two amps at a rather large price gap. $200+ probably won't buy you an empty lehmann BCL case, let alone the workmanship and the "real" components involved.


----------



## BlaBlaBla

New LC kit is on the way... Parts bought in Canada also...


----------



## BlaBlaBla

New LC kit is on the way... Parts bought in Canada also...


----------



## Knusperfisch

Cool let us know how it'll perform! I'm really curious about it^^
   
   
  Quote: 





> Hi Knusperfisch,
> 
> 
> 
> ...


 
  Well thats surely a bummer.
  Therefore I would never buy such crucial parts from a chinese guy at ebay. Because you will certainly always get fake parts no matter how genuine these may look like. I think that this should be clear to everybody and thats truly a fault by the buyer to some extend. You just can't expect that you will get real quality parts at low price thats naive. (at least not in china)  Thats just the risk you should be aware of if you're buying things over there.
  But on the other hand fake parts allow poor guys like me to get a headamp which I can afford. I'm just not able to spend vast amounts of money for a headamp as a student.
  Also you throw every fake part in the same pot. There should be mentioned that fake parts also differ from quality. Those in the LC or M-Stage seem to be relatively good if you're considering that Headfonia mentioned the M-Stage playing at a satisfying level even in comparison to the HA-160. Also I've never heard that one of these amps caught fire or so. I'm not defending fake parts it's just my honest opinion.
  Well... that the M-Stage killed someones headphones is a real pity.
  Fortunately the LC is getting tested before shipping^^


----------



## FlukeII

Quote: 





knusperfisch said:


> Cool let us know how it'll perform! I'm really curious about it^^
> 
> Well that's surely a bummer.
> Therefore I would never buy such crucial parts from a chinese guy at ebay. Because you will certainly always get fake parts no matter how genuine these may look like. I think that this should be clear to everybody and thats truly a fault by the buyer to some extend. You just can't expect that you will get real quality parts at low price thats naive. (at least not in china)  Thats just the risk you should be aware of if you're buying things over there.
> ...


 
  Whoa! Sorry didn't mean to touch a raw nerve here...But, after a couple of friends re-worked their Lovely Cubes, one of them encouraged me to post this stuff up here..
  After all we buy these Kits because they are a lot cheaper than the USD$800 for the real McCoy...but to get fake parts on top of that - I guess you take it or leave it; I figured you could do better, as when I had the chance to listen to these two side by side, the gap was bigger than the Grand Cannon IMO...The genuine Lehmann kicked arse - no wonder Lehmann wasn't on EBay getting the Lovely Cube pulled under a breach of US copyright - which incidentally is probably one of the most draconian pieces of legislation ever devised by industry and passed off as a Government initiative IMO!
   
  In the mods we came up with, we started trying to make the Lovely Cube sound like the original, when we figured we'd got there we went out and tried to make it sound better...this is where this post will go...
   
  IMO the Lovely Cube PCB is about the best thing, buying it on it's own and putting your own parts into the PCB saved a friend around 50% on buying the finished thing from those guys on EBay selling the completed PBA. (PBA= PCB with parts installed - industry term).
   
  Fakes to me are like playing Russian Roulette, yet get lucky sometimes, sometimes you don't - that was my case...I don't see any point in justifying why fakes should be supported IMO, but neither am I telling you what to eat for lunch either...
   
  For me, it took me all of 20mins to cut out the fake BD139s and BD140s from the Lovely Cube PCB, unscrew the BJTs from the board clean out the holes with a soldering iron and some solder wick, then install some new Fairchild devices! Switched it back on and was really taken back by the sound. Replacing the BC550 and BC560 with the higher gain BC560C and BC550C really picked things up - it took away a harshness that I would get with some music listening with my T1s.
   
  The rest of the MODs were fine tuning...


----------



## FlukeII

Quote: 





ringer said:


> I want to change 4700uF caps (that has dimansions 30x30 mm) on bigger caps 30x40 mm. Is it fit in Lovely Cube body?
> 
> (Sory for my English. I have a little talking experience.)


 

 You need to be careful about the size of capacitance of the smoothing capacitor you use; this is complicated, as it depends on a number of factors as to whether or not you blow up or stress your rectifier diodes at switch-on, and / or burn out the series resistors inline with the smoothing capacitors...
   
  If you use, say 30VA 15-0-15, Toridial, (Lehmann used a 28VA with quite good regulation compared to what you can buy off the shelf), the 3.3 Ohm Carbon resistors will limit the inrush current to the 4700uF filter cap, as well as providing a basic first-order LPF. However, too bigger capacitor, you run the risk of stressing those resistors or even blowing them up.
   
  To work this out, you need to know the internal resistance of the transformer's secondary, you can figure this out from the no load and full load output voltage, the difference between these two values times the full-load current will give you the internal resistance of the windings (Ohms law)
   
  Then the next thing to factor is the ESR of the smoothing capacitors, this is the only thing that will limit the inrush current into the capacitor when it is fully discharged - this is given in the manufacturer's data sheet, use the lowest value for calculation purposes, as the production tolerances of Electrolytics are pretty big, typically as much as +80%!
   
  Then through a series circuit, you can estimate the inrush current seen by the capacitors and the diodes, you can neglect the intrinsic resistance of the diodes, as this will be small.
  From the current you calculate, you can then figure out whether the peak inrush current is within the repetitive ratings for the diodes (see the datasheet - there's lot's of useful information, but it's just in the form of numbers), within the I^2t characteristics of any fusing, especially on the secondary side, and within the peak power rating/ Imax of the 3.3 ohm resistors.
   
  If you're hell bent on using a certain capacitor, like my friend had this 47.000uF 50V Electrolytics, that he mounted the rectifier and caps on the chassis, with Tag Strips. Being a NAIM Audio owner, and a believer in over-sized transformers, he went out an purchased 300VA 15V-0-15V toroid.
  On power up he blew-up the T1A fuses, no surprises I guess, then we he wired out the fuses; switched on again he blew up the 3.3 Ohm resistors that he'd wired from the rectifier diodes, no surprises here I guess when you think about it. So after he replaced the resistors with wire links and switched on, all the rectifier diodes exploded into little bits - that was way cool!
   
  He ended up getting much bigger Schottky diodes, which was fine, after wiring it all up, he blew the mains fuse on the transformer. It's not a good idea to go overrating the mains fuse on the primary otherwise you risk all sorts of trouble like blowing the internal thermal fuse of the transformer; it's only good for scrap then, as this fuse is usually buried in the middle of the windings.
  So we built a soft-start circuit with a 20 Ohm 25W power resistor and a 250ms switch on delay circuit that shorts the 20 ohm fuse in series with the Active (Live) connection to the transformer - it all works fine now....it was a good learning experience if not a little expensive!


----------



## Knusperfisch

Well alright you convinced me..
	

	
	
		
		

		
			




  50%? Dang...
   
  Well see if I'll tweak my device. I never soldered anything so I guess I'm a total klutz at it.


----------



## FlukeII

It's good to have a go...it's only a $90.00 board compared to trying to mod a $800 genuine article. Someone asked me to MOD their Lehmann after they heard the moded Lovely Cube belonging to a mutual friend. I was seriously sweating when I was desoldering the parts on the board!! In NZ money, that things cost about twice what it's worth, in relative terms, in the US!!
   
  Only advice is to cut the legs of the transistors with a good pair of side-cutters, don't try and desolder them unless you can get hold of a machine; else you risk damaging the holes and the tracks. Use Solder Wick to soak up the solder out of the holes...don't force anything...
   
  Good Luck!


----------



## rayshader

Quote: 





flukeii said:


> Quote:
> 
> 
> 
> ...


 

 While you have advocated against "fake" items, you then highlighted mods with the "real" stuff based on the so called inferior fake? The saving of 50% on the finished item? Talk about being thick or grateful. The 50% mounts to be around $100 for the time and effort spent by the seller is fully justified IMHO. If you so firmly believes in the real item, get the real BCL instead. You should mail Lehmann  on your mod on how just a few tweaks to improve the real thing exponentially. You never know you may end up getting a free pass to a German factory and earn royalities from your expertise. A real plus for someone against fakes.


----------



## JiggaD369

Rayshader,
   
  Flukell is only trying to help out us trying to mod this amp out.


----------



## FlukeII

Quote: 





rayshader said:


> While you have advocated against "fake" items, you then highlighted mods with the "real" stuff based on the so called inferior fake? The saving of 50% on the finished item? Talk about being thick or grateful. The 50% mounts to be around $100 for the time and effort spent by the seller is fully justified IMHO. If you so firmly believes in the real item, get the real BCL instead. You should mail Lehmann  on your mod on how just a few tweaks to improve the real thing exponentially. You never know you may end up getting a free pass to a German factory and earn royalties from your expertise. A real plus for someone against fakes.


 


  Sorry I didn't get your line of reasoning, nor is this a place to get personal?
   
  What we were trying to do was get as close to the real thing for as cheaply as possible...nothing more or less...we then thought we'd try some ideas; why not?
   
  This isn't expertise, it's just the findings of some experimenters having fun - at the end of it all we learned a hell if a lot out of it and had a lot of fun...it brought a group of guys together who had a common interest and we shared a lot of fun and time together....
   
  I doubt very much if Lehmann could care less what we were up to;  they have their reputation to protect and the last thing they'd bow over to was a bunch of guys screwing round with clone inferior PCBs from China, trying out various parts that we could get our hands on and seeing if our ideas actually worked...
   
   
  Why not post you mods and ideas? After all this is a place to share ideas, concepts, experimentation results - sorry if I've got this wrong?


----------



## BlaBlaBla

Peolpe, calm down please...
   
  Make amplifiers, not war!


----------



## JiggaD369

Quote: 





flukeii said:


> Quote:
> 
> 
> 
> ...


 
   
  Your input is greatly appreciated. I'm getting into this DIY thing and beginning to get hold of soldering practices so I'll be shooting yo ua long PM soon on these mods. Hope you don't mind!


----------



## BlaBlaBla

Here is interesting link:
   
http://tangentsoft.net/audio/opamp-bias.html
   
  Class A biasing with transistor and resistor. It is very interesting. You should try this.
   
  I have tried it (2N5484 + resistor 1k) on OPA 2107, and it sounds better than OPA627 alone (or OPA627 with 3.6k resistor alone). Temerature goes up, slightly, because (max) 5mA through Opamp.


----------



## Knusperfisch

Quote: 





> It's good to have a go...it's only a $90.00 board compared to trying to mod a $800 genuine article. Someone asked me to MOD their Lehmann after they heard the moded Lovely Cube belonging to a mutual friend. I was seriously sweating when I was desoldering the parts on the board!! In NZ money, that things cost about twice what it's worth, in relative terms, in the US!!
> 
> Only advice is to cut the legs of the transistors with a good pair of side-cutters, don't try and desolder them unless you can get hold of a machine; else you risk damaging the holes and the tracks. Use Solder Wick to soak up the solder out of the holes...don't force anything...


 
  Thanks for you're encouraging words ^^
  Yeah to solder some transistors shoulnd't be that difficult. Thanks for sharing your knowledge!


----------



## Comfortable

Let me assure you, not many counter-feits dont come from Hong Kong and average citizens are educated with high standards. There are many high end companies based there(one example is Kef), Hong Kong is not part of China, also assuming a product coming from Hong Kong use fake parts just because it's sold by a "chinese guy" is offensive.
   
  China have electronic scrap yards, checked for working order before being sold cheaply, that would explain some resistors' external condition and low cost.
   
   
  EDIT: 40 minutes later.


----------



## ringer

Could somebody tell me which 470uF caps in original BCL? I mean brand and voltage.


----------



## Comfortable

E-mail Norbert Lehmann at lehmannaudio.com. They change slightly over time. 2006 BCL's capacitator might be different than a new BLC, but i'll assume it has same specifications.
   
  And remember, Cloning is not illegal, counter-feits are. Stephen will never print "Lehmann" or "Black Cube Linear" on the clone, but don't mention Lovely Cube to Norbert, I have a feeling he won't like it 
	

	
	
		
		

		
		
	


	




. The should-be concern is "theft" of Intellectual properties(non patented), but it happens everywhere, even companies here in North America.


----------



## Knusperfisch

Quote: 





> Let me assure you, most counter-feits dont come from Hong Kong and average citpizen are educated with high standards. There are many high end companies based there(one example is Kef), Hong Kong is not part of China, also assuming a product coming from Hong Kong use fake parts just because it's sold by a "chinese guy", that's offensive.
> 
> China have electronic scrap yards, checked for working order before being sold cheaply, that would explain the resistors' external condition.


 
   
  Oh man..
  I never said that people in H.K. are not educated or got low standarts. I'm defenitaly aware of what living in H.K. is like.
  I was not saying that you HAVE to get counterfeit products if you're buying in Hong Kong. Of course there are shops and companies with high-quality products but I'm sure that the price also won't differ that much from american, japanese, european stores.
  Surely, H.K. is not a part of China but they got easy access to those scrap yards you've mentioned. So why not use this source which gives you a competitive advantage in comparison to the other countries?
  I was just saying that if you'll see an item which is sold at a quarter of the price the original is sold you may should consider that you'll get an item with counterfeit products. And by the way that is applicable to all over the world not only to H.K. .


----------



## BlaBlaBla

Quote: 





comfortable said:


> E-mail Norbert Lehmann at lehmannaudio.com...


 
   
  Is it worth to write email and send it to Norbert Lehmann because you want to know if caps are genuine? Do you think that he knows about every capacitor, resitor or PNP/NPN soldered in Black Cube Linear amp?
  He has to be genious, and probalby hasn't been sleeping last 10 years...
   
  Today all parts are fakes (not genuine). Last genuine part was made 10 years ago. By company that died because of too much "quality", and not enough "quantity". 
   
  Chinese parts can be very good quality (Corsair PC PSU - 7 years guarantee, Antec PSU - 5 years guarantee, Enermax - 5 years).
  Your "excellent" Denon headphones are "Made in China", ATH below 9xx also. Are they "bad"? Well, some Denons are pure crap (D2000 and below), but ATH is not.
  Nikon lenses and Canon lenses are "Made in China". Do you think that 70-200L IS or 70-200VR are bad quality? I doubt.
   
  I will ask the president of BMW, is it xenon bulb in my car genuine or not. I am shure that he knows all about it...


----------



## Comfortable

My reply was to ringer. He wanted to know the capacitator's brand and voltage.............. Believe me, Norbert will quickly and personally reply to your e-mails, you don't have to ask for him either..
   
  Also, audiophile products are a niche market and Lehmann products are even more niche, you can't compare it to BMW.. Somebody needs a reality check.


----------



## ringer

Quote: 





comfortable said:


> My reply was to ringer. He wanted to know the capacitator's brand and voltage.............. Believe me, Norbert will quickly and personally reply to your e-mails, you don't have to ask for him either..
> 
> Also, audiophile products are a niche market and Lehmann products are even more niche, you can't compare it to BMW.. Somebody needs a reality check.


 

  
  Thanks for advice. But I slightly shy to ask producer just because I want to copy they product.


----------



## BlaBlaBla

Quote: 





flukeii said:


> Quote:
> 
> 
> 
> ...


 

 He blew everything because 47 000 uF capacitors. They sucked up BIG amount of current, in a short time. That was reason why I asked you if 4x820uF are too much for output. Because Panasonic FM have *very low *resistance and they can suck up big amount of current. So everything what is in a circuit before them, will suffer. Some people say that it is not good to to put capacitors in a circuit that have capacitance bigger than 30%.
   
  Only benefit is (some of them say) to put capacitor with bigger voltage. Because better dielectric insulation.
   
  About genuine VS counterfeits...
   
  I compared products on ebay, and in store in my town, and they are the same. "On Semi" there - "On semi" here. On Semi is the same crap on ebay and in store in my town. On ebay I can buy same thing, for less money.
  First. Some people on this planet, do not have chance to buy something "special and genuine". And they have to use parts that are able to buy. Here we all talk about genuine parts, but we do not ask ourselves, who of us is really able to have those "genuine" parts. It is not cheap, to pay 10 USD shipping costs for part that costs 10 USD alone and can be bought from Canada or SAD (if you do not live there).
   
  Second. I have not seen any old TO92 or TO220 Philips or Toshiba transistors for a long time. All charts are from the previous century. Only new are those made in SMD technology. The same BC550C (On Semi) are on ebay, and in my country. Would I give, for example, 4 USD to _"XYZ seller"_ for one BD140? (In Croatia BD140 costs 1 USD) There is no guarantee that _"XYZ seller" _sells genuine parts. Who are they to keep old "genuine" parts in their storage? Probably they have been keeping parts (since 1996.) only because they are waiting for us ("Real HiFi connoisseurs")?
   
  Yeah. Certainly.  
   
_"XYZ seller" is highly regarded seller from Great Britain._


----------



## BlaBlaBla

Quote: 





comfortable said:


> My reply was to ringer. He wanted to know the capacitator's brand and voltage.............. Believe me, Norbert will quickly and personally reply to your e-mails, you don't have to ask for him either..
> 
> Also, audiophile products are a niche market and Lehmann products are even more niche, you can't compare it to BMW.. Somebody needs a reality check.


 
  Sorry. No offense. (Btw what is wrong with BMW?) ))
   
  Hold on, take a break and think about once more... First reason. Would you ask someone if his product is genuine even if it costs a lots of money (twice than competition)? Does not sound it naive to you? I mean, I bought something (or I want to buy) that is not "mass market product", I spent over 1000 USD and suddenly I ask seller:"If this capacitor is genuine?" Honestly, I someone asked me that, I would think that he is trying to make a joke with me. Second reason. Because he is seller, he wants to sell his product. So what do you expect him to say? Something like: "No! They are not genuine! I like to sell counterfeits!"


----------



## BlaBlaBla

I am really pissed off because all this babbling about "not genuine" stuff. So, before half hour I finished testing hFE with multimeter.
   
  -Toshiba 2SA1015/2SC1815 (bought on ebay 50 PNP and NPN on same rail) - 245-250
  -MJE243/MJE253 (bought here in Croatia 10 PNP and NPN) - MJE253 - 139-145, MJE243 - 95-103
  -1x BC179C - 560
  -1x BC179C - 420
  -2 x BC109C - 470-475
   
  -10 x BD139 - 132-152
  -10 x BD140 - 125-163
   
Now interesting part comes...
   
  -2 x BC550 (*stock LC*) - 11 (Whatever that means...)
  -2 x BC560 (*stock LC*) - 20 (Whatever that means...)
   
  -10 x BC550 (bought in Germany) - 8 (Whatever that means...)
  -10 x BC560 (bought in Germany) - 9 (Whatever that means...)
   
  If we compare numbers only (I do not care about their meaning-not any more) it seems that "not genuine" Toshibas have good results (small deviation between PNP and NPN). BC-s supplied with LC have higher gain than those bought in Germany. (reputable dealer). BDs (also bought in Germany - reputable dealer) have big difference between hFE. Greater than MJE (bought here in Croatia).
   
  My setup (right now) is two BC109C and two BC179C (big hFE difference like stated above) with stock LC BDs (probably not genuine). I measured (after 2 hours listening to music) less than 3mV DC offset. And that offset is EQUAL ON BOTH CHANNELS. We were talking about genuine/counterfeits/good/bad/ugly transistors... My amp is made of counterfeit parts. Why then is DC offset so small? Why I do not hear cracking? Why my headphones working better than ever? Why I am not able to hear any strange noises? Why I haven't died in flames caused by my counterfeit amplifier?
   
  I thing all this about genuine/conterfeit parts is overemphasized. Too much. I think we should listen to music more and less care about fu--- equipment.


----------



## DaEMoNteNTAcLe

can i has pitcah plz~?
  i is not good at reading number >_<
   
  tq.


----------



## JiggaD369

I think counterfeit doesn't necessarily mean you'll be covered with flames but rather what you're listening with counterfeit parts is not what the amp's design is capable of outputing.
   
  You can buy a counterfeit Sony LCD television in NYC which will look like a real Sony and output a picture but the picture quality will be nowhere near the same.
   
  Basically, the BCL was engineered to sound a certain way however, with the clone not being the same quality and possibly filled with some counterfeit parts, it might not be upto the same par as the BCL (SQ wise). 
   
  Then there's the longevity issue, also.
   
  P.s. I think the LC sounds awesome but if it is indeed loaded with counterfeit parts, then I can't imagine how good a real BCL sounds. I just wish I knew how to solder/desolder and match all these parts.


----------



## FlukeII

The 470uF 25V Electrolytic used to decouple the Diamond Output Buffer stages and the Op-Amp in the Lehmann Black Cube is a United Chemicon part, LXZ family.
   
  This part seems to be LXZ25VB471M10X16LL, 10x16mm. The specs on this part are pretty good for a switchmode supply type application: Zmax(100kHz)=68m Ohm, and Ir(100kHz)=1,050A, but at audio frequencies (1kHz), you only get about 85%.
   
  See the data sheet: www.*chemi-con*.com/files/*LXZ*0703.pdf
   
  You can get this part from digi-key: 470µF Aluminum Capacitor United Chemi-Con Radial, Can 25V ELXZ250ELL471MJ16SCAP 470UF 25V ELECT LXZ RAD - ELXZ250ELL471MJ16S - Capacitors.
   
  See: http://parts.digikey.com/1/parts/44912-cap-470uf-25v-elect-lxz-rad-elxz250ell471mj16s.html
   
  They cost USD$0.7 or USD$0.5 for 10 pieces, around USD$5.00 - This is where we got ours...


----------



## FlukeII

Incidentally, the orange axial capacitors used Vishay BCcomponents Polypropylene Film Foil Capacitors
 KP Axial Epoxy Lacquered Type:

   

 22nF or 20nF, KP460 URdc = 63 V; URac = 40 V: Bypass the 470uF Electrolytics used around the OPAMP and also used to bypass the 1,5uF MKP EPCOS capacitors on the input.
 100p, KP464 URdc = 630 V; URac = 200 V: One used on each of the non-inverting inputs of the OPAMP, connected to ground
   
  I think these parts have been discontinued by VISHAY. Also I heard that some of the newer Lehmann Black Cubes have switched to using a 20nF KP460 rather than the 22nF KP460 that I've seen in older builds of the Lehmann.
   
  I'm guessing they have gone around looking to buy up the last remaining stocks of these parts and had to settle for the 20nF values rather than the 22nF - who knows?
   
  There are other parts that you can try...more to come...


----------



## FlukeII

Just to put things into perspective, when I was in Shanghai last year, I picked up 5 of the Lovely Cube clone PCBs at an Electronics Market that a work colleague took me too. They cost USD$5.00 each - USD$25.00 for the lot. I actually paid the guy in USD as I had ran out of Yuan!!
   
  I think those guys on EBay are doing well for themselves...selling the Lovely Cube at those prices...It's what the market will stand I guess...
   
  The great thing with the markets in Shanghai is you can buy almost anything Electronic; there are a lot of factories there that will dump their end of line stocks and people will sell them in these markets...I got what I think are genuine ELNA SILMIC RFS 16mm dia x 25mm L, Capacitors, the guy had them in the ELNA bags of 100pcs and what looked like factory original packaging. boxed etc, I bought a broken bag of 470uF 25V caps, 50 pcs for USD$8.00 - this was unbelievable Digi-Key sell them for way more at USD$3.45 each!!!!!!!: He wanted USD$15 for 100 pcs!
   
  http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=604-1058-ND
   
  This guy had literally hundreds of them - my colleague asked where he got them from and it was from a factory making amplifiers for some Japanese company and that they had finished production with a lot of left over parts...my colleague a local, thought this guy was genuine...I reckon I got lucky too!


----------



## rayshader

Quote: 





flukeii said:


> Just to put things into perspective, when I was in Shanghai last year, I picked up 5 of the Lovely Cube clone PCBs at an Electronics Market that a work colleague took me too. They cost USD$5.00 each - USD$25.00 for the lot. I actually paid the guy in USD as I had ran out of Yuan!!
> 
> I think those guys on EBay are doing well for themselves...selling the Lovely Cube at those prices...It's what the market will stand I guess...
> 
> ...


 

  
  This is interesting. I don't mean to start a war. While at post #329 you made mention:
   
  Quote: 





			
				FlukeII said:
			
		

> /img/forum/go_quote.gif
> 
> Hi francisdemarte,
> Laser Collection's clones are not bad, I compared their PCB with the original Lehmann Black Cube Linear PCB and you would think the PCB’s have come from the same Gerber (CAD) .....
> ...


 
   
  Now you claim you bought 5 from shanghai last year while you were there? I highly doubt those PCB are that common given the only 2 variants that we have seen so far here. Lasercollection is not located in Shanghai, he is in Hong Kong. For $100 for a populated circuit there are time and work involved. I will be interested to know if you can do any better at this price. To go as far as to claim they are doing real well, maybe you should consider the superior price of the Lehmann vs the real components in your own words you said its not worth the money. In short you have condemned the real item for being too expensive and the cheaper closer option as a fake and guys making them are making buckets? LOL What a joke.


----------



## FlukeII

hey



 rayshader 
   
   
  LOL...The clones of the Lehmann Black Cube Linear are widely available in China - Check out: Taobao's Auction site: For example: http://item.taobao.com/item.htm?id=170113383 for one....490 Yuan or USD$75 isn't bad for an amp in a box!!!
   
  Sounds like you need to get out and see the world more?


----------



## rayshader

Quote: 





flukeii said:


> hey
> 
> 
> 
> ...


 

 Sounds like u need to learn how to lie properly. Getting from shanghai and buying off email don't mix in your tale.


----------



## FlukeII

Quote: 





rayshader said:


> Sounds like u need to learn how to lie properly. Getting from shanghai and buying off email don't mix in your tale.


 


  Let's square this up once for all - I haven't been completely honest here... I got the eBay Lovely Cube back in early 2010; It actually belonged to a friend who managed to blow it up and he asked me to fix it...
  Then when visiting Shanghai late last year I got to buy the boards from the market; At the market they advertised them as Lehmann Black Cube Clone boards - quite bold actually.
   
  Sorry, my mistake, I should have referred to them as Lehmann Black Cube Clone boards, not Lovely Cube.
   
  I got the boards for a bunch of other guys who were interested in building the clone amp -- we had a lot of fun.
   
  Just out of curiosity do you work for Lehmann? Are you a Lehmann distributor or retailer? You must have a motive for wanting to challenge someone's credibility - please tell me it's not jealousy?
   
  While you're at it check out this Lehmann on Taobao: http://item.taobao.com/item.htm?id=5994481434 or this one perhaps: http://item.taobao.com/item.htm?id=977771881


----------



## rayshader

Quote: 





flukeii said:


> Quote:
> 
> 
> 
> ...


 


  Go on ...cook me a lovely tale.  We can just flip the pages.I wonder why you haven't bought from Taobao instead. Please do us a favour, do us a review when you have gotten one from Taobao. Looking forward for the never ending tale of fakes. LOL Thanks for the entertainment.I wouldn't trust you to fry an egg to be honest.


----------



## FlukeII

Quote: 





			
				rayshader said:
			
		

> Go on ...cook me a lovely tale.  We can just flip the pages.I wonder why you haven't bought from Taobao instead. Please do us a favour, do us a review when you have gotten one from Taobao. Looking forward for the never ending tale of fakes. LOL Thanks for the entertainment.I wouldn't trust you to fry an egg to be honest.


 
  Ray, Ray, Ray,...
   
  You're barking up the wrong tree...it occurred to me while I was in the Bathroom that your thinking the boards I bought were finished or fully populated. Sorry my mistake, again...
   
  I interchangably use the term board to mean a PCB or PBA depending on the context...sorry
	

	
	
		
		

		
		
	


	



   
  The boards were blank, just Printed Circuit Boards or PCBs, not PBA or Printed Board Assemblies as they're known in the industry...what this means is there were no, I mean, *no* parts (components) installed or soldered to the boards I bought...
   
  I'm glad you're moderating this thread, as I guess you were confused? Hell, everyone reading this thread must have been confused...
   
  Please be a little nicer about it. It costs you nothing to be civil...
	

	
	
		
		

		
		
	


	



   
  Heres' a photo of the boards:


----------



## FlukeII

Getting back to the main topic:
   
  This is a schematic of one channel of the amp. Please note the component designators (R1, C2 etc) are wrong, but the values, 47E, 1,5K, BC550C I believe are correct.
   
  The voltages are helpful if troubleshooting a faulty board or you want to get an idea; these voltages *will vary* from board to board, due to component tolerances etc.
   
  Also, the components themselves will change their characteristics slightly with temperature change, for example expect to see the voltages measured in the circuit to change from when the amp is first turned on, from being cold, to when the amp has been runing after an hour or so -- this is normal.
   
  As an example, the Metal Film resistors you get from the likes of Mouser or Digi-Key can have a temperature coefficient (TempCo) variation from 50ppm to over 300ppm depending on make, model and design. Resistors like the expensive VISHAY Bulk Metal® Foil Precision Resistors, are super stable and super precise, typically available in 0.1% and 0.5% tolerances with a TempCo ± 8 ppm/°C (– 55°C to + 125°C) and ± 4 ppm/°C (0°C to + 60°C). If you're interested check out the VISHAY website, look for: Bulk Metal® Foil Technology Industrial Precision Resistors, VSR Series - this is what one of my mates used in his amp; just to be different. (VSR4, 47E or 47 Ohm and VSR4, 1,5k Ohm, as well as all the other values in the circuit. For the 10 Ohm Emitter resistors of the output stage he used: two VSR6 20 Ohm resistors in parallel for each 10 Ohm resistor position) Along with the other parts in the amp, it sound pretty cool.
   
  These voltages were measured on an original Lehmann Black Cube Linear:
   

   
  If you stick in different transistors, the voltages will fluctuate and change with the gain of those devices etc, if the voltages you measure are way out, may be more than +/-50%; I seriously think something is wrong with the circuit.
   
  Avoid using an old Analogue Style Meter (Ones that have a needle that moves on a fixed display) when measuring voltages around the BC560C and BC550C transistors. The internal resistance of these types of meters will affect the operating point of the circuit, also known as "loading the circuit" and can give false readings, or readings that seem there might be a fault. I have a FLUKE 189 meter that I cherish, but a FLUKE 110 or 112 is just as good - I personally like FLUKE meters a lot, But any good DVM (Digital Volt Meter) is OK, like HP, SANWA etc...Please don't take this as a beat up on analogue meters - they have there place too...it's just sometimes some tools work better than others...
   
  For what it's worth, the transistors mounted on the Lehmann board were:

 ON SEMI Brand: BC550C
 ON SEMI Brand: BC560C
 FAIRCHILD: BD139-16
 ST: BD140-16
   
  I've used these voltages as a guide, kind of reference point with the mods we were doing. If you get really different voltages and think the amp is working fine, I would be really interested to know!


----------



## BlaBlaBla

Quote: 





flukeii said:


> Getting back to the main topic:
> 
> This is a schematic of one channel of the amp. Please note the component designators (R1, C2 etc) are wrong, but the values, 47E, 1,5K, BC550C I believe are correct.
> 
> ...


 

 Default Vout voltages were +14.8V and -15.13V. Then I used 1k resistor and trimpot (200R) to tune Vout. Now Vouts are +14.16V and -14.2V. I lowered values on Vout to achieve minimal and symmetrical DC offset on both channels, and also I took care about difference between + and - (ideal is +14.2 - 14.2 but that does not give me satisfied results - DC offset 0.2mV and 4.5mV).
   
  Without trimpots I had 0 and 8.5 mV offset. But I do not like such numbers. I like keeping the balance. 
   
  Lower Vout (compared to Vin) means bigger heat disipation on regulators, but they are enough tough to sustain 0.5A each. When I do something I always try to make my most expensive device satisfied. That means - headphones. Good one are expensive, need 50> hours to burn in, and are hard to find here in Croatia. If you are able to handle DC signal in a good way, then your long time expenses are kept to a minimum. If someone talks about amplifier, my first technical question is:"How high is DC offset in your amplifier?" And then goes rest.


----------



## FlukeII

I forgot to mention, the VISHAY Bulk Metal® Foil Technology Industrial Precision Resistors, VSR Series resistors are very expensive. $$$$
   
  Personally I favour the VISAHY Vishay Beyschlag MBA 0207, Professional Leaded Resistors for all the positions in the circuit:
   





   
  I used the VISHAY MBB 0414, 1W 10E Resistors as the Emitter Resistors in the output stage. 
  Latter I cahnged these to three (3) 30 Ohm MBB 0207 resistors wired in parallel (10 Ohm) to replace each of the 10 Ohm Resistors; to my ears and mind this improved the slew-rate of the amplifier - making a change in the speed and impact of the sound to be faster and a little more punchy. Putting a 1kHz square wave into the Amp and looking at the slope of the waveform on a Oscilloscope, there was about a 14% improvement in the Slew Rate, steeper angle of dV/dt, after making this mod. Kostas Metaxas takes this to the extreme, check out his website: http://www.metaxas.com  This is an example of what I mean:
   
  Excerpt from IKARUS User Manual (downloaded off website):
   

   
   
  My experience with the sound of VISHAY BC MBB 0207 resistors in the Lehman Amp circuit has been:

 Fast and rythmic
 Clean mids that are a little warm,
 Detailed imagery
 Sound that was alive, but to me natural
 I found every song I listened to to be independent in timbre and tonal characteristics
   
  I was using the Beyerdynamic T1's and using a varity of Jazz and Alternate, such as Zero 7 - I really like their music and the variations on a single CD or Album!
   
  I would be really interested to know what others have tried. One of my friends has used all 5% Carbon Resistors and likes the sound a lot - It wasn't to my taste.


----------



## Knusperfisch

Quote: 





> -2 x BC550 (*stock LC*) - 11 (Whatever that means...)
> -2 x BC560 (*stock LC*) - 20 (Whatever that means...)
> 
> -10 x BC550 (bought in Germany) - 8 (Whatever that means...)
> -10 x BC560 (bought in Germany) - 9 (Whatever that means...)


 
   
  Thats really interesting..
  Have you also measured the BD139 and BD140 from the stock LC compared to the BD139/140 you've bought ?


----------



## ringer

Quote: 





knusperfisch said:


> Quote:
> 
> 
> 
> ...


 

 As I know you can not measure hFE of low power transistors by average multimeter. Only BD139/140 could be properly measured in Lovely Cube KIT.


----------



## ringer

My ST BD140-16 transistors has hFE from 192 till 205.


----------



## BlaBlaBla

Quote: 





knusperfisch said:


> Quote:
> 
> 
> 
> ...


 

  
  Unfortunately, I have not measured stock LC BDs...
   
  My intention was not to get right values. I wanted only to compare transistors. If I get wrong result for LC BC, the same error I will get for another BC (because they are the same PNP and NPN). But difference between those two errors will represent exact value.
   
  Vishay is excellent brand. I use their products as much as I can. Their products are better and more reliable tham most hifi oriented companies.


----------



## francisdemarte

> Default Vout voltages were +14.8V and -15.13V. Then I used 1k resistor and trimpot (200R) to tune Vout. Now Vouts are +14.16V and -14.2V. I lowered values on Vout to achieve minimal and symmetrical DC offset on both channels, and also I took care about difference between + and - (ideal is +14.2 - 14.2 but that does not give me satisfied results - DC offset 0.2mV and 4.5mV).
> 
> Without trimpots I had 0 and 8.5 mV offset. But I do not like such numbers. I like keeping the balance.
> 
> Lower Vout (compared to Vin) means bigger heat disipation on regulators, but they are enough tough to sustain 0.5A each. When I do something I always try to make my most expensive device satisfied. That means - headphones. Good one are expensive, need 50> hours to burn in, and are hard to find here in Croatia. If you are able to handle DC signal in a good way, then your long time expenses are kept to a minimum. If someone talks about amplifier, my first technical question is:"How high is DC offset in your amplifier?" And then goes rest.


 

  
  I believe the M-Stage uses the same method. You can see the trim pots in this image. I wonder how the LCB can avoid the use of these trimpots?


----------



## BlaBlaBla

Quote: 





francisdemarte said:


> > Default Vout voltages were +14.8V and -15.13V. Then I used 1k resistor and trimpot (200R) to tune Vout. Now Vouts are +14.16V and -14.2V. I lowered values on Vout to achieve minimal and symmetrical DC offset on both channels, and also I took care about difference between + and - (ideal is +14.2 - 14.2 but that does not give me satisfied results - DC offset 0.2mV and 4.5mV).
> >
> > Without trimpots I had 0 and 8.5 mV offset. But I do not like such numbers. I like keeping the balance.
> >
> ...


 
  Yes. I did the same thing like in Martix M Stage.
   
  The main fact is that Vout imbalance of almost 1V is equal to 18-20mV DC offset on headphone output(I have measured that). And second fact is that you will never hear big difference if there is not balance between + and -, because the same imbalance is equal on both channels (left and right). That topology has also bad point that is "low channel separation" (but also previous mentioned strong point that is in equal supply less prone to imbalance). That is reason why is more important to match left PNP (or NPN) with right PNP (or NPN) than trying to find "left PNP" - "left NPN" combination with equal hFE.


----------



## ringer

Guys, what do you think about quality of resistors in LC? Which do you think will be better to replace?


----------



## BlaBlaBla

Quote: 





ringer said:


> Guys, what do you think about quality of resistors in LC? Which do you think will be better to replace?


 
  I think that they are (at least) 30% better than those in Matrix M Stage.
   
  If you want to replace resistors then start with resistors in signal path (around Opamp and BCs). Next are output 10R resistors (1W). 1W is too small. 2W will be better. All others (before and after regulator)  I will not replace. They do not affect the signal too much.


----------



## ringer

What do you think about Epcos LongLife electrolythic caps? Is it good enough for replacing 4700uF capacitor?


----------



## FlukeII

Quote: 





ringer said:


> What do you think about Epcos LongLife electrolythic caps? Is it good enough for replacing 4700uF capacitor?


 


  It our experiences, it's kind of like renovating a house - it's not complete until you've done everything. Yes you do get some gains replacing some parts, changing out the ELNA 4,700uF cap with a Low ESR type from VISHAY BC COMPONENTS - MAL205857472E3 - CAPACITOR, 4700UF, 40V we reckon you get quite an improvement in the bass and speed of the sound. The Low ESR caps seem to work best over the so-called audio caps from ELNA and NICHICON. (_The Lovely Cube board we got had ELNA 4,700uF fitted)_
   
  Replacing the 3,3E CF resistors between the diode with a 1 Ohm (BI Technologies, BPC 5 1,0E 5W 1%) Thick Film resistor that has very low ESR ESL we think added to improving the pace and timing, along with the 4,700uF upgrade to the VISHAY MAL205857472E3 (This resistor is expensive and the audible gain wasn't worth it - sorry this is something just pointed out to me). _Taking the resistors out all together seems to give the best sound - they seem necessary to prevent the 1A fuses on the original Lehmann Board from Blowing when you first turn on the power - the inrush current to charge the 4,700uF is quite high. _(Update)
   
  Probably the single biggest impact was going from a 30VA 15V-0-15V toroid to a 60VA 50VA or 100VA 120VA 15V-0-15V Toroid added a real increase in the presence of the mids, especially noticeable on vocals like Diana Krall; we found that one of biggest changes came with changing the Power Transformer:
  Step 1: MULTICOMP - MCFE030/15 - TRANSFORMER, 30VA, 2 X 15V (Farnell Order Code: 9531726) - Sound's like a Lehmann

 Step 2: MULTICOMP - MCFE050/15 - TRANSFORMER, 50VA, 2 X 15V (Farnell Order Code: 9531785) - Get more mids presence, timing seems to pick-up

 Step 3: MULTICOMP - MCFE120/15 - TRANSFORMER, 120VA, 2 X 15V  (Farnell Order Code: 9531874) - Faster paced sound with real dynamic range, emotional impact of the music.
   
  These are the best transformers we could find locally, you can get Nuvotem-Talema, these are really good but expensive...another guy uses: Nuvotem Transformer,toroidal,80VA,2x15V,2.67A (RS Stock No. 422-5269) (Nuvotem Manufacturer's part number 92422-P2S2).
   
  The 300VA Transformer did not seem to make any audible improvement over the 120VA model...at least to me. *(300VA Transformer mentioned in previous post)*
   
  One of my friends prefers the sound with 100nF rectifier diode capacitors removed from the board - says it gives a more in your face sound with rich PRaT; he used the AD823N Op Amp over the OPA and also uses a Super Better Transistor circuit to feed the V+ and V- to the Op Amp. I'll post a diagram of the Super Beta Filter if anyone is interested?


----------



## FlukeII

Quote: 





blablabla said:


> I think that they are (at least) 30% better than those in Matrix M Stage.
> 
> If you want to replace resistors then start with resistors in signal path (around Opamp and BCs). Next are output 10R resistors (1W). 1W is too small. 2W will be better. All others (before and after regulator)  I will not replace. They do not affect the signal too much.


 

 I've found that 1W Resistors work OK in the output stage as the 10 Ohm Emitter Resistors, it's just they look kind of small on the board. Getting the ESL (Effective Series Resistance Inductance) down by putting smaller resistors in parallel I found helps to improve the slew rate.

   
   
   
  Those Emitter resistors are only dissipating around 20mW in heat, 2W is really over kill from an Engineering standpoint. The BC MBB 0207 0,6W in parallel are fine.
   
  Changing the value of the 10E Emitter resistance changes the DC Operating point of the circuit, it also helps to degenerate some of the gain; Don't change 10E value - it screws up the operating point of the circuit...
   
  To get the offset as low as possible, I've found that BlaBlaBla is correct, by setting the supply rail voltages to have the same magnitude |-15.4V| = |+15.4V| - However, the other half of the story is to match the Beta and VBE of the BC560C and BC550C - we're pretty sure this is what Lehmann does and would explain the hand-soldering on their Wave Soldered boards.
   
  We used a *METEX Instruments H-5040D* DMM (belonging to a friend) with Transistor Gain Measurement to do this. Don't pick up the transistors with you bare hands, the heat dissipated will  change _affect _the readings. We ended up buying 250pcs of the FAIRCHILD BC560C and BC550C @NZD$0.04 each initially, before I switched to using the PHILIPS parts, we only managed to get hold of 100pcs of these.
  The other guys are quite happy with Fairchild parts. We found that there was no noticeable difference with using the PHILIPS / NXP BC546C / BC556C or BC557C / BC547C.
   
  We also found that the cheap no name brand DMM we had initially to measure Hfe wasn't very good, results drifted around, the meter only cost NZD$20 - the METEX gave much better results...
   
  Please let me know if you try the Emitter resistor MOD above and how you find the sound?


----------



## FlukeII

If you're interested, someone sent me this link on transistors matching:
   
  http://www.musicfromouterspace.com/analogsynth/TRANSISTORMATCHER/TRANSISTORMATCHER.php
   
  Happy experimenting...
   
  If someone is looking for a book that ( I think) gives a good introduction to Electronics, check out: Tab Electronics Guide to Understanding Electricity and Electronics [Paperback]
 G. Randy Slone. For more advanced ideas around troubleshooting and stuff that isn't taught in Engineering School or in the text books, check out: Bob Pease's books:

 Troubleshooting Analog Circuits (EDN Series for Design Engineers) [# ISBN-10: 0750694998 or # ISBN-13: 978-0750694995]
 Analog Circuits (World Class Designs) [# ISBN-10: 0750686278 or # ISBN-13: 978-0750686273]
   
  These aren't the only books on Earth, there are a lot of very good texts, the above is just a suggestion; I learned a lot from Pease's books.


----------



## FlukeII

Quote: 





> Originally Posted by *FlukeII* /img/forum/go_quote.gif
> 
> 
> Changing the value of the 10E Emitter resistance changes the DC Operating point of the circuit, it also helps to degenerate some of the gain; Don't change 10E value - it screws up the operating point of the circuit...
> ...


 

 Two extra clarifications to make here:
   
  1. The total resistance of the resistors in each BD139 / BD140 Emitter Resistor should remain 10 Ohms: You can use 3x 30E in parallel, or even 10x 100E --> The total resistance is 10E
   
  2. The Metex meters only measure Hfe (at a preset current, i think it is around a few milliamps(?)) - you can't measure VBE. You need another circuit for that - see the link above.
   
  In an ideal world it would be best to match the transistors under the identical conditions used in the circuit, e.g. same Ib and Ic, Ie etc. So even using the Metex doesn't mean that the transistors are matched as well as they could be - I guess it's a matter of how far do you go. This is to do with the shape of the Ib vs Ic vs V graphs for the transistors, you may get a match at one point of Ib, but get a gap at another Ib test current or operating value: Have a look at the data sheets for the BC560C and BC550C and compare the graphs for Transistor gain etc they vary a lot...
   
  Certainly, using the Metex meter and going through to get about 60-70 matched PNP and NPN transistors measuring and noting the values displayed, we managed to get pairs that where within 2% 20% of each other - this gave a DC offset on the output that was around +/-0.01V - in one case we managed to get the DC Offset to about -0.002V, almost a factor of 10 better -> took a lot transistors to get to, we ended up measuring all 250pcs - You could say this was a bit extreme...
   
The reason for doing 60-70 pairs, was we wanted to see if the gain ranges of the BC560C and BC550C transistors had much affect on the sound - we couldn't hear any difference in the transistors we tried - we didn't test all the devices, we picked 10 pairs across the sample we made: Probably it was a waste of time; but we wanted to see - why not? 
   
We do think that the higher gain C Hfe ranking of the BC550 and BC560 sound better than the lower A or B Hfe ranked devices. (These parts are available from the manufacturer in different gain ranges)
   
UPDATE: We found that we could get consistently close values of Beta (2 -5% for transistors) for NPN Transistors, but there was always a gap of at least 10 - 20% between the gains (Hfe) of the PNPs - I guess with the ON SEMI devices and the more wider spread of gain values, with enough transistors tested, you could probably get very close matches between the PNP and NPN devices. With the 100 PHILIPS devices we ended up seeing very close gain values between the NPN or PNP devices, but a quite a gap when comparing the PNP and NPN gains - nevertheless we still ended up with a DC off-set better then 0.01V or 10mV  - I think this is good enough(?). I checked with a high-end manufacturer of one brand of headphone amplifiers and he said that they would let their kit go out of the factory provided the DC Offset was under 20mV or 0.02V.
   
  We set out an A3 piece of paper divided up into 1" x 1" squares (1" is easy to measure with an imperial ruler) and went through the NPN transistors writing down in pencil the value of the Metex meter, after we filled all the squares, we got out the PNP and started measuring the devices until we got readings that were identical to the NPN devices. This process took us about 3 days - you can only do so much in a day and you have to have beer and chill-out, it's boring as hell!
   
  A friend works for a local company who makes domestic audio equipment and this is similar to the process they follow when matching transistors for the differential input pair of their amplifiers. (For what it's worth, he mentioned you can get the ON Semi versions of the BC550C and BC560C cheaper than the Fairchild ones, but he made note that the processes ON Semi use seem to mean that they have seen a much wider range of spreads of transistor gains, in some cases they have needed as many as 1000 pcs to match up 300 or so pairs for the PNP diff pair.
(They also match the current mirror NPN transistors to the same gain as the PNP, and <-- This was incorrect). It was a similar story with the number of transistors to go through for the PNP NPN pair matching. In no way are the ON Semi devices inferior, they are just different from a production spread point of view. He reckons they'll spend up to two - three working days before a production run to sort this out.) These guys were trying to match up NPN pairs and PNP devices. Thinking about it, if DC Offset is _your _thing, the ON Semi devices may be the way to go?
   
Either way you end with a lot of transistors that aren't a lot of use in less you're going into production...
   
I still feel that the PHILIPS BC550C and BC560C have a better tonal characteristic than the Fairchild devices  - it's personal taste...
   
  The following gives an example; the NPNs under the Diff Pair form a Current Mirror and the PNPs are the Diff Pair - for more info see Doug Self or Bob Cordell's books:

   
   
   
  We're playing around with a Bob Moog circuit to see if we can make it work to be able to measure PNP and NPN transistors...so far the results aren't great. Here's the circuit construct:

   
UPDATE: The issue with the Moog Circuit for matching transistors is that it's fine for matching NPN or PNP transistors to one another, but requires trimming to make it so that you can use it to match the PNP to NPN transistors. The reasons for this are the component tolerances in each of the testing circuits. The reason for matching the gains in the first place is to get as best as possible symmetric amplification of the +ive and -ive cycles of the audio signal, as well as getting the DC offset as low as possible. However, the 47E resistors in the legs of Base connections in the BC560C and BC550C provide some degeneration so that the characteristics of the stage aren't completely dependent on the Hfe of the transistors: If you want to know more about this read Doug Self's book Audio Power Amplifier Design Handbook, 5th Edition for example.
   
While the buffers are a unity gain design, e.g. Av=1, if you inspect the output waveform with 1kHz sinewave going in to the input, you see that the +ive amplitude of the sinewave cycle will be slightly different than the -ive cycle (this is called Waveform Asymmetry) - the matching of transistors helps to deal with this. How far you go is up to you - But, you'll never get it perfect that's impossible there are too many other variables at play to achieve that. Even laser trimmed OPAMPs such as the OP627 still exhibit some waveform asymmetry in the few devices I have played with.
   
Having a DC offset in the first place isn't all that bad, but too much offset, say more than 100mV, will disturb the dynamic characteristics of the headphone drivers (speakers) and affect they way the music sounds; low impedance headphones seem to be more affected - e.g. less than 100 Ohm. Some manufacturers will, I understand, compensate for this in the magnetic design of their drivers; others don't - it's a cost thing.Personally, the lower the DC Offset, the better, if you can get it right down then go for it.(Too much DC Offset and you'll damage the voice coil windings of the driver - not a good look, my Grado's smelt real good after that circuit I was playing with failed - see previous posting about the 2SD669As).
   
one of the reasons I prefer AKG, Beyerdynamic and Sennheiser headphones is because they engineer their drivers from the ground-up e.g. raw materials to finished product. I understand that some other manufacturers buy-in their drivers and I personally don't think they have the level of control over the design quality and performance that AKG, Beyer and Senn can achieve. The trouble is, with these brands you get what you pay for, I own a Senn HD-25 II and HD-218 headphones, to me the HD-25s eat the HD-218. (I own 8 pairs of headphones, but I don't have a flash stereo system - why? They all sound different and I like to switch between them; there are things that sound better in the AKG K-240s I have than the T1']s for example...it's just life!)




   
I recently bought a pair of Chinese made AKG K-271 MkII, the other AKG headphones I own, K-141 and K-240 were Austrian made. I really feel that HARMAN have gone too far with their cost cutting and the new K-271MkII is a compromised design IMO. To my mind the older K-271, Austrian made sounds better - a friend owns these. 
Trouble is, Harman is run by lawyers and accountants (IMO) who seem to have one loyalty - the share holder IMO. I think this drives a culture of profit before quality while exploiting the reputation of a very good brand such as AKG. I understand that AKG no longer manufacturer in Austria their range of headphones. Shame, I think the Austrian build and quality was much superior to the Chinese cost improved models. This isn't a beat up on Chinese made - in China you get what you pay for...


----------



## BlaBlaBla

I think that we will have the best results if we make custom Lovely Cube. So far, we analized (almost) every part in the circuit. Design is simple enough to be very cheap but also good sounding if good parts are used.
   
  Maybe someone who has a small factory reads this, and after few weeks he will start to make modified PCB that includes free space for all modifications and upgrades. It would be great. I will buy one or two. 
   
  I am too lazy to do the PCB alone.


----------



## JiggaD369

Is there anyone who can match these parts for us?


----------



## BlaBlaBla

FlukeII, I was on internet page that you had sended to us...
  That workshop is better equipped than my university. Multimeter costs twice than Lovely Cube alone.... 
   
  Man, in that demand for perfection, you have gone too far.


----------



## FlukeII

Quote: 





blablabla said:


> FlukeII, I was on internet page that you had sended to us...
> That workshop is better equipped than my university. Multimeter costs twice than Lovely Cube alone....
> 
> Man, in that demand for perfection, you have gone too far.


 

 Hi BlaBlaBla,
  Electrical Engineering is my livelihood and I learnt early on having good test instruments can save a lot of hassle and bother – they don’t have to be new, just good and reliable.
   
  I guess if you want to make Electronics a long-term hobby, investment in a reasonably good Digital MultiMeter (DMM), for example, will always hold you in good stead.
   
  Sorry good test equipment isn’t that cheap; But it will last, the first Fluke DMM I bought (FLUKE 89) cost me a lot after 14 years I gave it away to relative when I bought the FLUEK 189, now 20 years on that FLUKE 89 is still going strong. Also, when you do something dumb when measuring a circuit, like trying to measure a voltage with the Amps range, you want to know that the only thing that has blown is the fuse in the DMM! I’ve done this a few times with my FLUKE, carelessly not thinking and/or tired, and was relieved when the internal fuse was replaced everything worked OK – One of my friends bought a much cheaper DMM and had the same misfortune, the only problem was that after he replaced the internal fuse in his DMM, the DMM still did not work!
   
  This isn't a sales promotion on FLUKE by the way, I've seen some great DMM's from DIGITECH and SANWA that cost half what a FLUKE110 would cost.
   
  Personally, I would really like an Audio Precision 2722 Analyzer for screwing around with with Audio Circuits: Check out: http://ap.com/products/2700 Only trouble is these cost around USD$20K! I know I'm dreaming, but it gives you and idea of the relative cost of a good DMM to an industry benchmark like the 2722 Audio Analyzer. I know someone who works in the US for a large corporate who makes Audio products and he mentioned to me once that at their factory in Texas they had several of these 2722 analyzers as well as about 6 of the older AP Two (This is a discontinued version: It's commercial names was "System Two" from Audio Precision: They do come up on Ebay from time to time; if you buy one be prepared to send if back to Audio Precision to get is aligned and tested - it will probably need updating. Also make sure you get the PC Card Interface - if the model you acquire needs it - these are not cheap from Audio Precision!!) versions, these still cost around USD$18K a piece. Where I work we have an AP Two - I use it from time to time for my projects.
   
  I'm just trying to set the scene - this is the kind of investment some manufacturers will go to.


----------



## JiggaD369

Hey Flukell,
   
  Are you still going to post the spreadsheet with the caps you tried around the opamp?


----------



## FlukeII

Quote: 





jiggad369 said:


> Hey Flukell,
> 
> Are you still going to post the spreadsheet with the caps you tried around the opamp?


 


 There is more to come, I've just been busy with other things i.e. work.
   
  Other things:

 User a Super Beta filter to fed the OpAmp
 OpAmp changes: I like the LME49720, but friends prefer the AD823, NE5532 even! Personally, I think the OPA2134P is a little dull sounding, it's polite, but to me lacks punch, on the other hand the AD823 is more in your face presentation...
 Power Supply mods
 Triming the LM337/LM317 voltage regulators to get the +ive and -ive voltages equal


----------



## FlukeII

And the different capacitors for the power supply stage; as well as alternatives to the United Chemicon LXZ 470uF 25V Electrolytic used to decouple the various stages in the amp...


----------



## BlaBlaBla

Yesterday I ordered LME49720HA... I will try it in combination with 2N5087/5088 and matched MJE243/MJE253.
   
  Hi FlukeII, what do you think about stock TO220 heatsinks (in LC)? I think that amplifier is too warm. I mean, I do not believe in sentence "it is A class so it has to be warm". Problem is there is not enough place for bigger heatsink...
  
  Quote: 





flukeii said:


> Quote:
> 
> 
> 
> ...


----------



## ringer

Quote: 





blablabla said:


> Yesterday I ordered LME49720HA... I will try it in combination with 2N5087/5088 and matched MJE243/MJE253.
> 
> Hi FlukeII, what do you think about stock TO220 heatsinks (in LC)? I think that amplifier is too warm. I mean, I do not believe in sentence "it is A class so it has to be warm". Problem is there is not enough place for bigger heatsink...
> 
> ...


 


  It has to be warm. Because in class A transistors are always open.


----------



## BlaBlaBla

Quote: 





ringer said:


> Quote:
> 
> 
> 
> ...


 


  But I really do not like when it becomes warm! I do not like when transistors are hot (over 60°C) and I do not care about commercial trick "it works best when it is warm". I am sure that class A amplifier can be cold and still operate in A class. Best amlifiers behave in that way, because designers are not trying to save money on the most important thing - cooling. But this minimalistic design just sucks. Small design involves high noise, too much heating and all components in it have shorter life.
   
  I bought a few of these heatsinks: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280498961521&ssPageName=STRK:MEWNX:IT I also bought a few heatsinks from local store that are higher than those supplied with LC. Because of mimimalistic design I will have to improvise (drill extra holes, etc)...
   
  Output resistors (1W) become brown (I do not like that because they were white as new) and also know that good resistors do not change color, unless they are overloaded), so I concluded that 1W is not enough. Besides, I can not find who made them. Maybe some "Middle of nowhere" company from China? Mills is too big (5W). Riken, Shinkoh are to expensive (5-10 USD each) Vishay is sick (10-15 USD each), Takman (2 USD each) I like more in the signal circuit, Alan Bradley I have never tried... Kiwame 2W are the best choice...


----------



## BlaBlaBla

Quote: 





ringer said:


> Quote:
> 
> 
> 
> ...


 


  But I really do not like when it becomes warm! I do not like when transistors are hot (over 60°C) and I do not care about commercial trick "it works best when it is warm". I am sure that class A amplifier can be cold and still operate in A class. Best amlifiers behave in that way, because designers are not trying to save money on the most important thing - cooling. But this minimalistic design just sucks. Small design involves high noise, too much heating and all components in it have shorter life.
   
  I bought a few of these heatsinks: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280498961521&ssPageName=STRK:MEWNX:IT I also bought a few heatsinks from local store that are higher than those supplied with LC. Because of mimimalistic design I will have to improvise (drill extra holes, etc)...
   
  Output resistors (1W) become brown (I do not like that because they were white as new) and also know that good resistors do not change color, unless they are overloaded), so I concluded that 1W is not enough. Besides, I can not find who made them. Maybe some "Middle of nowhere" company from China? Mills is too big (5W). Riken, Shinkoh are to expensive (5-10 USD each) Vishay is sick (10-15 USD each), Takman (2 USD each) I like in the signal circuit, Alan Bradley I have never tried... Kiwame 2W are the best choice...


----------



## ringer

Quote: 





blablabla said:


> But I really do not like when it becomes warm! I do not like when transistors are hot (over 60°C) and I do not care about commercial trick "it works best when it is warm". I am sure that class A amplifier can be cold and still operate in A class. Best amlifiers behave in that way, because designers are not trying to save money on the most important thing - cooling. But this minimalistic design just sucks. Small design involves high noise, too much heating and all components in it have shorter life.
> 
> I bought a few of these heatsinks: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280498961521&ssPageName=STRK:MEWNX:IT I also bought a few heatsinks from local store that are higher than those supplied with LC. Because of mimimalistic design I will have to improvise (drill extra holes, etc)...
> 
> Output resistors (1W) become brown (I do not like that because they were white as new) and also know that good resistors do not change color, unless they are overloaded), so I concluded that 1W is not enough. Besides, I can not find who made them. Maybe some "Middle of nowhere" company from China? Mills is too big (5W). Riken, Shinkoh are to expensive (5-10 USD each) Vishay is sick (10-15 USD each), Takman (2 USD each) I like more in the signal circuit, Alan Bradley I have never tried... Kiwame 2W are the best choice...


 

  
  That radiators will conduct worm from transistors. But the case will not cool down while radiators inside. If you want to cool down all stuff in the case there are two options:
  1. Make active cooling
  2. Pull out radiators from the case


----------



## BlaBlaBla

I found old Riken Ohm RM resistors. But... Very expensive.


----------



## JiggaD369

Quote: 





blablabla said:


> I found old Riken Ohm RM resistors. But... Very expensive.


 


  How would Kiwame 2W resistors work for the 1W resistors?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Quote:
> 
> 
> 
> ...


 

 I heard that there is something written like P=U2/R and P=I2*R where I - current through resistor, U - voltage across resistor, R - resistance
   
  When I calculate few things I get something close to 1W for 10R resistance.
   
  But to be honest, I give a crap about books.
   
  I always use my intuition. My sixth sense. First I take part into my hands, and then I decide what to do. I have never decided wrong. Probably because I do not waste time calculating too much (because nothing is ideal like it is stated in book) and because I like to exaggerate ("old school way of thinking" where everything was twice as big and oversized, but has lasted few decades). So I will put there 2W. And if I could I would put there 5W Mills.
   
  Moreover, I like green color of Kiwame resistor and also like how word Kiwame" (Ki-Wa-Me) sounds. It is simple word (name) and easier to remember than phrase "*some crappy no-name metal film, made in Middle of nowhere*".
   
  Same goes for next brands:
   
  Word _Riken_ (Ri-ken) reminds me on car plates in my town (RI-xxx-xx). 
   
_PRP_ reminds me on something strong, effective. P - R - P
   
_Mills_ has mellow "M" and beautiful "sssss".
   
_Caddock_ has big "D" (in croatian language). Something "Deep", "Dark", "Dreadful". Wow.
   
  Shinkoh has heavenly "Shhhh" and it is beautifully crafted. So simple and so styli*sh* (you see - "sh").
   
There is some art, in those words above... 
   
   
*People, please no offense... I was joking!   *
   
  JiggaD369, use ohms law and do not bother with small digits. Everything abowe 1W (2W and more) will be ok. It depends only about free space in your amplifier. It is very uncommon using 1W resistors in output stage. I mean, output stage is not place for saving money...


----------



## Whitefox

Quote: 





ringer said:


> That radiators will conduct worm from transistors. But the case will not cool down while radiators inside. If you want to cool down all stuff in the case there are two options:
> 1. Make active cooling
> 2. Pull out radiators from the case


 
  There are still way use the enclosure as a radiator.
 But it's best if the aluminum case...


----------



## oliverws

Removed


----------



## oliverws

Removed


----------



## oliverws

Removed


----------



## FlukeII

Quote: 





blablabla said:


> But I really do not like when it becomes warm! I do not like when transistors are hot (over 60°C) and I do not care about commercial trick "it works best when it is warm". I am sure that class A amplifier can be cold and still operate in A class. Best amlifiers behave in that way, because designers are not trying to save money on the most important thing - cooling. But this minimalistic design just sucks. Small design involves high noise, too much heating and all components in it have shorter life.
> 
> I bought a few of these heatsinks: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=280498961521&ssPageName=STRK:MEWNX:IT I also bought a few heatsinks from local store that are higher than those supplied with LC. Because of mimimalistic design I will have to improvise (drill extra holes, etc)...
> 
> Output resistors (1W) become brown (I do not like that because they were white as new) and also know that good resistors do not change color, unless they are overloaded), so I concluded that 1W is not enough. Besides, I can not find who made them. Maybe some "Middle of nowhere" company from China? Mills is too big (5W). Riken, Shinkoh are to expensive (5-10 USD each) Vishay is sick (10-15 USD each), Takman (2 USD each) I like more in the signal circuit, Alan Bradley I have never tried... Kiwame 2W are the best choice...


 

 What you're saying here sounds like something is wrong with the circuit - probably those fake components goofing things up - joke
	

	
	
		
		

		
			




   
  What are the voltages across the 10E Emitter reistors in the output stage - from the designs we've played around with, it should be about 0.4V DC +/-0.05V DC; the range we measured across 6 amplifiers. The voltage will change when ac signal is fed into the input. These voltages were measured with the volume turned down to min and no input signal i.e. idle condition...
   
  From a power / heat dissipation point of view the dissipation in those resistors is P=V^2/R or (0.4x0.4)/10 = 0.016W, If that resistor is getting warm, something is wrong - way wrong. You shouldn't be able to feel that heat in a reistor of that size (with your finger) until the heat dissipation gets around 0.25W - 0.3W - Some people are more sensitive - it just depends on how much skin is on your finger...


----------



## FlukeII

Quote: 





blablabla said:


> Yesterday I ordered LME49720HA... I will try it in combination with 2N5087/5088 and matched MJE243/MJE253.
> 
> Hi FlukeII, what do you think about stock TO220 heatsinks (in LC)? I think that amplifier is too warm. I mean, I do not believe in sentence "it is A class so it has to be warm". Problem is there is not enough place for bigger heatsink...


 
   
  How hot those transistors get depends on a few things, other than the DC operating point that they have been set to with the values of the resistors, namely the 1,5k resistors in the output stage.
   
  Provided the Tjmax of the BD139/BD140s is not exceeded, you can run those transistors pretty hot to the touch - i.e. 50 deg C is not uncommon. (See the Datasheet for details of operating temp)
   
  Personally I don't like 50degC as there is little margin if things go wrong or you stick the amplifier on a table in the Sun and the Sun cooks the enclosure and the BD139/BD140s get way hotter. When I've designed circuits with power transistors or just heat dissipating parts, I try to avoid getting the device hotter than 35degC under ambient temp conditions (e.g. 20degC Air Temp) - measured using a thermal imaging sensor.
   
  Sometimes you just have to design it in to run hotter because of cost and / or design constraints, or use a fan: I don't like fans as they eventually break down and you have to put thermal protection circuits in to guard your circuit on the day the fan(s) fails else you might end up with a Fire in your box! _Update: Actually fans are bad (IMO) generally, they're noisy, without filtering they will suck dirt and dust into your equipment, the new modern ones tend to create some electrical noise, especially conducted noise on the DC supply running the fan, Actually, on one design this was how we measured when the fan failed by sensing the ripple voltage noise created on the DC supply rail when the fan was running. Sometimes they are a necessary evil - you have no choice but to use one._
   
  Remember the hotter you run those parts, the lower the MTBF: As a rule of thumb, for every 10 deg C hotter you run a device with a specific MTBF figure over the stated temp for that MTBF, you end up halving the MTBF figure. As an example, let's say a specific manufacturer quotes the MTBF for an OPAMP with 100,000 Hrs before failure at an operating temp of 25 deg C. If you now operate that OPAMP at 50 35 deg C, (_correction_) you can expect that OPAMP to fail after 50,000Hrs - whether it does actually fail or not depends on a lot other factors...
   
  The Heatsinks in the original Lehmann I think were picked on a cost vs performance basis: As a manufacturer you try to *avoid* over-doing things, i.e. put more heatsinking in than you really need or can get away with; you're just wasting money and chewing into your profit margin if you do! (Don't forget Lehmann and any other manufacturer is in business to make money, the fact they do audio, is just the conduit they've decided to pursue to make money)
   
  You can stand the transistors vertically on the board, as per the M-Stage, and use a heatsink that has a better dissipation capability e.g. One of the guys I know used this heatsink style vertically mounted on the board:

  I don't have access to his gear to show you a photo, but the heatsinks stand vertically as per the M-Stage design, side by side, in the same position as the heatsinks that were lying flat on the board. He pulled out the pins and just used a PK Self-Tapping screw through the PCB to hold the heatsink down. He also earthed the heatsinks via the Self-Tapping screws to the ground plane.
   
  Another guy wants to use a special heatsink similar to the following:
   

   
  Again the transistors are mounted vertically, and the heatsink would be secured to the board via the holes in the PCB for the old heatsinks. I don't know where he's got with this - he was trying to find someone to mill the heatsink to fit the board last time we chatted about it. _UPDATE: The reason for this is the design being used increased the current through the output transistors by replacing the 1,5k resistors with 1k Resistors ; I don't know if this works or not, we were talking about replacing the output devices with some SANKEN 2SC4883 and 2SA1859:_
   
  Personally, I used a slightly bigger version of the heatsinks used in Lehmann's original design, I bought them from RS Components: AAVID THERMALLOY TV4G:
   

   
   
   
  I never actually thought about the heat dissipation being an issue with the Lehmann design: It's seems warm to the touch but, OK I guess. I focused my attention to the electrical performance and operation of the design more...


----------



## BlaBlaBla

FlukeII, you were right about resistors and voltage across them. Mine have also 0.45-0.5V. Even 0.5W will be enough. But resistors are not expensive. 2W or 1W it does not matter... Usually, people look at bigger resistors with greater respect.
	

	
	
		
		

		
		
	


	




  
   
  Unfortunately TV4G will not fit in this small piece of sh--/box. Maybe, only in a place for regulator (LM) but not in a place for BD. When I see such a small space for heat sinks (in today's amplifiers and similar stuff), I become sick. But I found solution...
  I buy the drugs. A lot of them. Word "optimization" makes me sick.
   
  Recently, friend told me that adequate (working) temperature for regulators is 35-45°C. For output stage 40-50°C. That means 15-30°C above room temperature. This amp goes 30-45°C above. I always ask myself why all amplifier designers trying to spare money on few metal parts.  And I still can not find a good answer. Especially when "that something" comes from "not so cheap" and respectable company. Is the same situation in Burson HA160? I do not know. It seems that housing is the most expensive part of an amplifier.
   
  On the other hand there are amplifiers that have excellent cooling. For example,Shiit Asgard (that has been my first choice, but then I decided to buy LC). In it transistors are connected directly to housing. But it is so hot that lots of users have found it good in a kitchen and have used it as a stove. (Maybe that is reason why Shiit Asgard is more prefered by women than men...) Unfortunately, I do not cook very often.


----------



## FlukeII

Quote: 





blablabla said:


> FlukeII, you were right about resistors and voltage across them. Mine have also 0.45-0.5V. Even 0.5W will be enough. But resistors are not expensive. 2W or 1W it does not matter... Usually, people look at bigger resistors with greater respect.
> 
> 
> 
> ...


----------



## BlaBlaBla

Quote: 





oliverws said:


> There is still very little impressions and comparisons being made regarding this amp, would be great if those of you who got it can send in some of your thoughts about the amp?


 
   
*Hi, oliverws!*

 My subjective view... Compared to Matrix M Stage, Lovely Cube is less sterile and more involving. My Lovely Cube has 20% better sound stage (more wide and better positioning). Sound is more "into your face" than "laid back" as is in Matrix M Stage. DC offset is less (almost two times) and it is less warm. Matrix M Stage, compared to stock Matrix Mini I, compress sound stage. Lovely Cube represents stage as it is in Matrix Mini I amp.
   
  Because sound stage, imaging and etc. depends on opamp, capacitors and everything in your circuit, and LC is tunable, you will not find exact comparation...
  In my case there are ERO MKC and KP on input, KP is in opamp bypass, and *stock* Philips Tin Foil in a circuit connected with ground. Input caps are *stock* Nichicon Gold Tune 4700uF, output caps are Panasonic FM 470uF, regulator caps are* stock* ERO MKT (input and output) and tantalum 10uF on Vadj. Buffer transistors are BC109C and BC179C (CDIL and NXP), output transistors are* stock* BD139 and BD140. Others have something else. 
   
  If you want more data, you should ask FlukeII. Technically, he is more involved in LC project than others, and he has right equipment to measure it and take out a conclusion.
   
  But the fact is that you should not take our measurements too serious because, as I said before, *one component* can change entire picture... My opinion is that LC is worth money, and sound wise, it will be better than Matrix M Stage. If you want try DIY, lovely Cube is "a must". 
  Here we have lots of advices. Sometimes fight is very close 
	

	
	
		
		

		
		
	


	




 and that is because all people have different opinions. But after all, it is all about DIY. 
	

	
	
		
		

		
		
	


	



   
_*Oliverws*__*, do not bother with data. Just DIY! *_


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## oliverws

Removed


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## oliverws

Removed


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## BlaBlaBla

Quote: 





oliverws said:


> And one more thing, about the things being said that it gets quite hot. It won't keep me from not having to place the musiland with rubber feet on top off the amp will it?


 

 Lovely Cube goes hot but does not melt rubber... 
   
  Quote: 





			
				oliverws said:
			
		

> /img/forum/go_quote.gif
> I listen to mainly Genesis and songs in general you'llwant to hear every nuance off every instrument. Will use it along side Musiland 02 US and a pair of AKG K701. Have had Audio-gd DAC19+C2 before but am now looking for something a little bit slimmer. And hoping im not downgrading myself too much with this purchase in comparison to the audio-gd setup.


 
   
  Why you did not say earlier what headphones do you want to drive...
   
  I will try to be as simple as possible. I think that AKG K701 are not good match for Matrix M Stage, Audio GD C2 or Lovely Cube. Those are cheap amplifiers. You should look above 1000 USD. WAY ABOVE.
   
  People think that AKG K701 is best buy, and that they will have "ultimate sound" on every amplifier that has "enough power" to drive them. Well, that is not true. Because if you want to drive them properly, you will have to spend a lot on amplifier. A LOT. I had Matrix M Stage. A lot of people here were talking that "M Stage is match from heaven for AKG K701". Well it is my ass. It had power but for what? For moving drivers? I can do that with my finger... K701 sounded artificial, sterile and lifeless. But when my friend paired K701 with Leben, that was different world. Sound was warm, fast and full of life. There was SOMETHING.
   
  If you want to try different amp and DIY, that is excellent. But do not expect wonders. No offense but you have not heard 30% of your K701 headphones (Like all others with cheap amplifiers (below 1500 USD) who believe in fairy tales written in well paid reviews) ... Lovely Cube will not help you in that. Asgard will not help you. Audio Gd will not help you. What will help you are VERY EXPENSIVE tube amps, because they will give K701 warmth and life. And they will use in a good way K701s ultimate precision, extra sound stage and flawless feeling for details.


----------



## purrin

^ You forgot to add that if you are going to get a very expensive tube amp (> $1,500 USD), you may as well throw the K701s in the trash and get something better. 
	

	
	
		
		

		
		
	


	




 But ya, I agree with you - the K701s need the right amp. Although it's possible that folks like the K701+LC combo for it's bass control and speed.
   
  @oliverws: you may be going in the wrong direction moving from away from the AGD DAC19 + C2 to the Musiland + LC setup, at least for the K701s.


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## taiyoyuden

I thought this amp is supposed to be good with the k701. If it's not, at a reasonable price, what is?


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## BlaBlaBla

Quote: 





taiyoyuden said:


> I thought this amp is supposed to be good with the k701. If it's not, at a reasonable price, what is?


 

 It is good, but not outstanding...


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## purrin

It's probably the cheapest amp I can think of that can power the K701 properly. K701 is a tough one to amp properly. It needs two things:
   

 Enough power (which is hard but possible to find cheap, but LC fits the bill. Asgard, A-GD too for a bit more.)
 The right kind of sound while not taking away the K701 strengths (which is not possible to find cheap.)
   
  Personally, I wouldn't touch the K701 with the LC/M-Stage/LBCBCL. But the LC+K701 setup at ~$500? would be hard to beat if you are into that kind of sound (detailed, fast, and controlled.)


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## Knusperfisch

Did you mean with BLC the Lehmann BCL ?
  If yes, you really think that this combo wouldn't work well ?


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## purrin

Quote: 





knusperfisch said:


> Did you mean with BLC the Lehmann BCL ?
> If yes, you really think that this combo wouldn't work well ?






   
  Yeah, that's what I meant. Here is where I'm coming from:
   
  A couple of years ago, I actually had the K701 for a month and ran it with a fairly pricey balanced SS amp. I even tried burning the K701 in for 300 hours. I really tried to like it. My problem with the K701 was that it sounded cold, dry, and sterile. One way to compensate is with a tube amp. However, "reasonably" priced tubed amps just don't control bass well or have good treble extension, thereby they limit the potential of the K701, which have the capacity to provide very controlled bass and extended treble.
   
  For something that may not break the bank, I would consider maybe a hybrid like the Schitt Lyr for the K701 instead of the BCL/M-Stage/LC. I've yet to hear the Lyr, but I'll get a chance in a week at the NorCal meet.
   
  But that's just me. YMMV.


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## JiggaD369

Agreed.
   
  K701 is a fine piece of gear but just not my cup of tea. And a M^3 is more than enough to power it.
   
  And $1000+ for a amp? Are you kidding me? That is just rediculous.
   
  Please spend that money on something more meaningful in life.


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## BlaBlaBla

Quote: 





jiggad369 said:


> Agreed.
> 
> K701 is a fine piece of gear but just not my cup of tea. And a M^3 is more than enough to power it.
> 
> ...


----------



## purrin




----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Agreed.
> 
> K701 is a fine piece of gear but just not my cup of tea. And a M^3 is more than enough to power it.
> 
> ...


 
   
  What will be meaning of our lives when third world war is in front of our doors? I could spare money for ticket to Mars...
   
  Live when you still can.


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## JiggaD369

Not everyone is rich.


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## BlaBlaBla

Quote: 





jiggad369 said:


> Not everyone is rich.


 
   
  Well it depends what you like to do, in your life.. I like visiting bordels and spend all my money on whores and cheap whiskey. 
	

	
	
		
		

		
		
	


	



  Sometimes I put some money into amplifier or headphones. But that is only when my wife stays at home, because I forgot to give her money for shopping. 
	

	
	
		
		

		
		
	


	



   
  For God's sake, I have to neutralize her babbling with something (whiskey does not help in that)...


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## Knusperfisch

Just heard my LC the first time. It is my first headphone amp and until now I've also never listened through an amp. The improvement is not thaaat big but what I've experience until now is that the sound gets really more detailed, the harshness is reduced to a fair amount  and a much better location of the instruments. (Just heard for about 30min so thats my very first impression)
  So the LC seems to do it's work quite well.
  By the way the DC Offset of my stock LC lies at 2.5mV and 0,09mV which is pretty good!


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## BlaBlaBla

Quote: 





knusperfisch said:


> Just heard my LC the first time. It is my first headphone amp and until now I've also never listened through an amp. The improvement is not thaaat big but what I've experience until now is that the sound gets really more detailed, the harshness is reduced to a fair amount  and a much better location of the instruments. (Just heard for about 30min so thats my very first impression)
> So the LC seems to do it's work quite well.
> By the way the DC Offset of my stock LC lies at 2.5mV and 0,09mV which is pretty good!


 
   
  DC offset is good. Measure DC offset after 30 hours of listening to music... If it is the same, everything is ok. Your headphones will be happy and last  for a long time.
   
  You have to wait for 20-30 hours. After that, bass will go deeper and mid frequencies (vocals) will become more "in front". Sound stage will become slightly wider. Today I was listening to music on laptop from my brother. Then I saw what really means "crappy sound".
  Now, LC shines again. 
	

	
	
		
		

		
		
	


	



   
  So if you think that your equipment is not "up to standards", try to listen to music on something that is "usually sold" (mainstream) on the market. Then you will run to your old equipment and suddenly feel heavenly revelation.


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## Knusperfisch

I've got a question. Is it normal that I've got a DC offset of max. 5mV at a gain of 20dB while I've got 11mV at a gain of 0 ?
  Should the DC offset stay constant within the burn in time ? Is it normal when it rises or is this a bad sign ?


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## BlaBlaBla

Quote: 





knusperfisch said:


> I've got a question. Is it normal that I've got a DC offset of max. 5mV at a gain of 20dB while I've got 11mV at a gain of 0 ?
> Should the DC offset stay constant within the burn in time ? Is it normal when it rises or is this a bad sign ?


 
   
  Hi, Knusperfisch!
   
  I will answer to you, but first I would like to try to explain something.
   
  Let say in this way. DC offset depends (mostly) on your transistors.  But let say that you cannot change your transistors (because that demands soldernig another transistors and "guess and error" game play),  you can replace regulator resistors with potentiometer (trim pot).  That is easier. And you can change an opamp. Without any tool.
   
  DC offset depends (mainly) on those two things mentioned before. (regulators and opamp). I tried five (5) opamps. OPA2134, 2132, 2107, 2x627, 2xAD797. All this opamps had different DC offset. Some of them had (AD797) very high offset (11mV), and some of them too god to be true (OPA 2107 - 1mV).  Situation becomes more complicated if you try to put opamp into A class. And it changes if you change gain (0, 10, 18, 20 dB).
   
  So it depends on lots of things.
   
  You can improve DC offset if you do fine tuning of regulator voltages. Because LC have exactly the same voltage on both channels you can raise or lover positive or negative voltage on LM317 or LM337 regulators. That will make small "drift" (push pull) but only what matters is situation on headphone output. So it does not matter if you have for example +15.1V and -14.95V after regulators . DC gain (as I said before) changes with gain, so you will have to choose gain that suits your headphones the best, and then tune DC offset.
   
*DC offset of 11 mV only matters if you have low impedance headphones like Denon, Grado, ATH. In that case 5 mV or below*, will be better because two things. First is that low impedance headphones need small voltage to be driven, and *small DC offset involved in entire signal will make sound bad*. Second is rule U2/R=P. U - DC offset, R - impedance, P - power dissipated into your headphones because DC offset.
   
  I*f you have high impedance headphones like Sennhesier (300 Ohm) or Beyerdinamic (600 Ohm) then DC offset can be as high as 20-30 mV*.  The reason is the same, like stated before. High impedance headphones need more voltage to be driven, so *DC offset is less involved into entire signal*. And power dissipated into headphone coil is less, because bigger resistance.
   
  Also, you have to look at technical specification of you headphones, especially in stated power (in mW) where you have to divide that stated power with number two (2) (because of some other things...).
  But power does not tells you all. Some headphones are easy to drive, and some not. For example ATH W1000X is rated about 500-1000 mW AND EASLY DRIVEN. AKG K701, for example, is rated to 100 mW and *NOT EASLY DRIVEN*. So, with AKG you have to be very careful and have* flawless* amplifier - if you want to raise your volume. You will need a good amount of power (closer to headphones rated power, than with ATH, for the same amount of volume)* WITHOUT DC offset*. AKG K701 coils do not forgive if they are overpowered with wasted power (DC), but in the same time they need a lot of power. ATH forgive much more wasted power (DC), and need less power to be properly driven.
   
  That is reason why I always talk about  *VERY GOOD* amplifier, when someone says:  "AKG K701".  You should try different amplifiers. You would be amazed how power sensitive (quality dependent) AKG K701 are.
   
  Sorry for bad english. I tried to explain as much as I could.


----------



## taiyoyuden

A related question, does the maker measure the DC offset during testing as well?


----------



## BlaBlaBla

Quote: 





taiyoyuden said:


> A related question, does the maker measure the DC offset during testing as well?


 
   
  You can not know that. If we talk about mass market amplifiers, so if there is a lot amplifiers to make and sold, probably someone turns amplifier for 5 min on,  and sees if there is going something wrong (overheating, oscillation, bad sound). But I do not think that someone is trying to measure DC offset. Especially if he is making 100 amps per day. And has to sold them out.
   
  But if we talk about small market products, (for example LC, CK3, M3, Lehmann, etc) then seller might be the person who is checking DC offset before the amplifier goes away. (If you want LC assembled, seller will try amplifier before sending it to you.) Also, I know that  LC is sold in very small quantities ... Smaller quantity, in most cases means - better quality control. Probably.
   
  But, again, what is the meaning of  "to check DC offset"? It depends... Maybe that person considers that value* "under" 20 mV is satisfied* or maybe that *10 mV is "not good enough"*?
   
  In first case, as a buyer, you might be disappointed with quality control because 20 mV is quite high for "low impedance headphones" (just my opinion)...
  But in second case, maybe you will be stunned with a value of a few mV... 
   
  Because too many sentences that start with "it always depends.....", I trust only to myself. 
	

	
	
		
		

		
		
	


	



   
  You should check DC offset, always when you buy an amplifier, or after you bought an amplifier.  At least, your headphones will be happy and serve you for a long time. I think that is not good to rely on seller's words, when you might kill headphones that cost 200+ USD alone...


----------



## JiggaD369

Hmm, I think I learning what all this DC offset is all about, now. Thanks bla.
   
  But what confuses me is one channel is 14.3 mV and the other is 4.2mV. Is something wrong? I tried every gain setting but it's always about ~10mV apart. 
   
  P.s. I use 2107.


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Hmm, I think I learning what all this DC offset is all about, now. Thanks bla.
> 
> But what confuses me is one channel is 14.3 mV and the other is 4.2mV. Is something wrong? I tried every gain setting but it's always about ~10mV apart.
> 
> P.s. I use 2107.


 

 Nothing is wrong. Because of transistor mismatch, you have DC offset. In a circuit of regulators (LM317 and LM337), instead 1.1k resistor, you can put 1k resistor, and in series with that new 1k resistor - 200R trimpot. Then you should lower the Vout voltage of both regulators for about 0.5 volts and tune it to the lowest possible offset. "Sweet spot" in my setup is +14.2V and -14.25V. But I have BC109C and 179C regulators. You have to find "sweet spot" in your setup. It really does not matter if supply voltage is 15V or 14.5V or 14.2V.
   
  But do not go under 14V because regulators could start dissipate too much wasted power (*21V*-*14V* = *7V*, lets say *7Vx0.3A* = *2.1W*, *2.1W*27C°/W* = *57C° above room temp*)
  Usually, for high demanding loads (headphones are not that kind of load) Vin - Vout is around 3V. In Lovely Cube Vin-Vout is 6V (21V-15V = 6V) that means better stability on Vout, but also bigger heat dissipation. Bigger Vin-Vout difference menans better stability but needs bigger heatsink. Smaller difference means lower stability but also smaller heatsink.


----------



## Knusperfisch

Thanks Bla !
  That really brought some light in the dark.
  But one thing I'd really like to know is whether it i normal that DC offset goes up with more play time? I used the LC for maybe 10 hours or so and the DC offset rises slowly every with every time I'd put it on.


----------



## JiggaD369

Quote: 





blablabla said:


> Nothing is wrong. Because of transistor mismatch, you have DC offset. In a circuit of regulators (LM317 and LM337), instead 1.1k resistor, you can put 1k resistor, and in series with that new 1k resistor - 200R trimpot. Then you should lower the Vout voltage of both regulators for about 0.5 volts and tune it to the lowest possible offset. "Sweet spot" in my setup is +14.2V and -14.25V. But I have BC109C and 179C regulators. You have to find "sweet spot" in your setup. It really does not matter if supply voltage is 15V or 14.5V or 14.2V.
> 
> But do not go under 14V because regulators could start dissipate too much wasted power (*21V*-*14V* = *7V*, lets say *7Vx0.3A* = *2.1W*, *2.1W*27C°/W* = *57C° above room temp*)
> Usually, for high demanding loads (headphones are not that kind of load) Vin - Vout is around 3V. In Lovely Cube Vin-Vout is 6V (21V-15V = 6V) that means better stability on Vout, but also bigger heat dissipation. Bigger Vin-Vout difference menans better stability but needs bigger heatsink. Smaller difference means lower stability but also smaller heatsink.


 


  Bla, thanks for the insight!
   
  Excuse my lack of knowledge as I'm a newwbie but would you mid posting a picture of the trimpot setup you have? I looked inside of the LC but the space is so small I don't know how I can achieve this.
   
  Also, any perticular reason why did you replace the regulators? How do they desipate heat since they seem like metal cans?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Bla, thanks for the insight!
> 
> Excuse my lack of knowledge as I'm a newwbie but would you mid posting a picture of the trimpot setup you have? I looked inside of the LC but the space is so small I don't know how I can achieve this.
> 
> Also, any perticular reason why did you replace the regulators? How do they desipate heat since they seem like metal cans?


 

 No problem. I will post pictures tomorrow.


----------



## JiggaD369

Hey bla,
   
  I found a matched pair of Philips BC109C (rare) but I can't seem to find the BC179C anywhere! Do you know any place where I can buy them or is there a substitute for it?


----------



## fhkhan109

Is there any way to get these green PCBs for Lehmann clone? The quality seems to be pretty nice. I am planning to build one with components from digikey or mouser. Thanks.


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Hey bla,
> 
> I found a matched pair of Philips BC109C (rare) but I can't seem to find the BC179C anywhere! Do you know any place where I can buy them or is there a substitute for it?


 

 http://www.banzaimusic.com/BC179C.html
   
  Here I bought BC109C and BC179C. BC179C is made by CDIL. Today, it seems that CDIL is the only one who makes old BC transistors. In my amp, transistors work fine, and have big hFE. According to my measurements, BC109Cs have 600-650, BC179Cs have 700-740. If you can, buy them 4 or 5 and try to find the closest pair.
   
  Closest component that I found was BC550C with hFE around 560, and BC560C with hFE mostly below 600 (a few of them have hFE 600-620).
   
  But BC transistors are hard to match. Their hFE is high, but vary a lot (150). Also I found that american 2N (2N5087/5088) has lower hFE (450) but also less fluctuation accross the range (50). The most tight variations have 2SA1015/2SC1815 (20), but hFE arround 400.


----------



## BlaBlaBla

Quote: 





fhkhan109 said:


> Is there any way to get these green PCBs for Lehmann clone? The quality seems to be pretty nice. I am planning to build one with components from digikey or mouser. Thanks.


 

 I am also interested and if someone finds PCB, I will buy a pair...


----------



## JiggaD369

So would you recommend going with the matched Philips BC109C i found and the BC179C from Banzai (hard to obtain) or something else like the BC5XX (easily available from USA)?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> So would you recommend going with the matched Philips BC109C i found and the BC179C from Banzai (hard to obtain) or something else like the BC5XX (easily available from USA)?


 

 It is really a metter of personal taste. I think BC109C/179 and 2N5087/88 will work perfectly. When you want to replace european transitor (BC) with american (2N) or japan (2SA/2SC), you have to pay attention on pins. They have different orientation. I would not suggest you to use japan transistor (in european or american topology) because their base pin is not centered like on american or european transistors... Always read technical documentation about transistor that you want to buy.
   
  With BC109C and BC179C, you have to take care about voltages. They are not rated as high as BC550/560... Supply of LC is +15V/-15V. BC109C VCEO is rated for 20V. There are resistors that reduce voltage, but  always measure to be 100% sure.
   
  BC5xx will do the job but you will have to buy them 20 and find good match. If you can choose (and find) use the one that have hFE above 500.


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Bla, thanks for the insight!
> 
> Excuse my lack of knowledge as I'm a newwbie but would you mid posting a picture of the trimpot setup you have? I looked inside of the LC but the space is so small I don't know how I can achieve this.
> 
> Also, any perticular reason why did you replace the regulators? How do they desipate heat since they seem like metal cans?


 
   
  Picture is here...
   

  
  I do not have Lovely Cube at work. So I made a drawing.
   
http://img228.imageshack.us/i/94348873.jpg/


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Bla, thanks for the insight!
> 
> Excuse my lack of knowledge as I'm a newwbie but would you mid posting a picture of the trimpot setup you have? I looked inside of the LC but the space is so small I don't know how I can achieve this.
> 
> Also, any perticular reason why did you replace the regulators? How do they desipate heat since they seem like metal cans?


 
   
  Pictures are here:
   
http://www.freeuploadimages.org/images/77fd8d139u5gp9lcpbet.jpg
   
http://www.freeuploadimages.org/images/8izqfkmnx6534me8n4v6.jpg


----------



## JiggaD369

Thanks bla!
   
  Great clean job!
   
  I will add two trimpots to my mouser order! 
	

	
	
		
		

		
		
	


	



   
  BUT, I have a question regarding the buffer stage.
   
  I also want to replace the 2 BLUE tinfoil and 2 RED MKC caps around the Opamp. The statesd values are 100pF and .022uF, respectively. DO I have to replace them with the ame values or can I go up? If so, how much?


----------



## francisdemarte

Awesome job fitting those trim pots in! How did the yellow tantalums you have in there affect the sound?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Thanks bla!
> 
> Great clean job!
> 
> ...


 
   
  If you want to replace blue tinfoil capacitors I would suggest you to replace them only with polystyrene (Styroflex).  Stock Philips Tinfoil is not up to date capacitor, but has its own strength. It gives you more "in front" sound presentation.  If you replace Tinfoil with WIMA MKP (I would not do that at all costs) you will have more rounded sound. Too rounded. Personally I do not like WIMA capacitors and I avoid them.  ERO MKC is (maybe) slow and old but it has "something". (But it is up to you.) Polystyrene is excellent choice here. It gives very wide (and almost magically "air") sound stage. And they have excellent precision and dynamic over entire frequency range. I would not change capacity because if you put there bigger cap then you might have high frequency roll off. If you put there lower capacity then OPAMP will amplify very high frequencies that  might put transistors in to oscillation. 100pF represents frequency filter that does not let to high frequencies to pass through OPAMP. If you do not notice any roll off, then 100pF is good.
   
  Capacitors for OPAMP coupling is just another story. 22nF is optimum between too slow and to too little. If you want to change something then you should choose better cap. Personally I do not know if MKC are good caps for coupling, because I put there blue ERO KP 1830 - 1% (some people say that they are "the best" for coupling). Also tried WIMA, but that crap I will avoid for a long time. As I said before - too round and artificial. If you put bigger cap that means bigger capacity (reserve for OPAMP) but also means slower reaction. Philosophy always goes toward this: "If you have two capacitors in parallel connection, then bigger one always represents "power tank", and smaller one always represents "speed". " I tried bigger and slower cap. Smaller cap (10nF) polystyrene has more impact on sound that bigger (47nF). But in my case, 10nF polystyrene gave me too much sound stage and too weak vocals. It was not good combination with quite fast Panasonic FM. 47nF polystyrene was better in vocals but it was like entire frequency range went up. Too bright. Again not good with Panasonic FM.
   
  ERO KP capacitor has flawless positioning and precision. It is good for opamp coupling. For DC blocking ERO MKC is better. MKC has sparkle and posses power in mid range (vocals) that KP and polystyrene do not have. MKC has in front presentation. KP has better separation and positioning (slightly back than MKC) but less power in vocals. Polystyrene is wide, laid back and "air" and has the least power in the mid range.
   
  I think that for small caps, polystyrene are excellent. Polystyrene is also good for DC blocking but it has to be in a combination with something that has strong mid frequency range. ERO KP is good for coupling, and MKC is very good for DC blocking. (In my case.)
   
  But it all depends on your headphones, and type of music that you like.


----------



## BlaBlaBla

Quote: 





francisdemarte said:


> Awesome job fitting those trim pots in! How did the yellow tantalums you have in there affect the sound?


 

 Usually, capacitors in supply region also affects the sound.  Polystyrene has more air and mild presentation, very fast and has precision. MKC has strong mids and "in your face" presentation but tends to mild things. Good MKP posses precision and bigger and (very clean) power than polystyrene but it is not so wide. MKT has power like MKP but harsh and sterile presentation (MKP is better). Tantalum capacitors? It is pure power cap, with direct presentation and it demands something in parallel....
   
  It is good to put 10uF or even 22uF in Vadj circuit of regulator. It gives better noise rejection and stability. In regulator output (Vout) circuit it is good to put the smallest cap (that you can without putting circuit into oscillation).
   
  BUT HERE we have 470uF electrolytic capacitors after regulator and close before transistors. So capacitors mentioned before (story about MKP, MKT, MKC etc...) do not affect sound too much in this case...
   
   
  Electrolytic 470uF capacitors represent main power reservoir for output. They collect (suck) power directly from regulators much faster that headphones can spend. They collect already "cleaned" power (small voltage jumps are cleaned with Vout caps). Bypassing 470uF capacitor will mean that you "clean" power once again. Too much voltage "cleaning" leads to artificial and "boring" sound.
   
  If you remove Vout capacitors and put them in parallel with 470uF capacitors then you can have bigger influence on sound. But also might put circuit into oscillation. Without oscilloscope this is not worth doing. It is not safe.
   
  Removing 470uF capacitors will give you (according to some people) the best sound, in a way of sound stage, dynamic and speed. I tried that, and it is true (for driving ATH).
   
  But this involves weak bass and total absence of  "punch and grunt" for "more demanding" headphones like AKG...


----------



## JiggaD369

Bla, what voltage rating is that tantalum? Because those things are priceyyyyy!
   
  Perhaps we should start a new thread: "Modding your Lovely Cube!". 
	

	
	
		
		

		
			




   
  I can't even keep up with all of this info. being thrown around.


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Bla, what voltage rating is that tantalum? Because those things are priceyyyyy!
> 
> Perhaps we should start a new thread: "Modding your Lovely Cube!".
> 
> ...


 

 10uF, 25V
   
  Pricey but not like other capacitors... 
   
http://cgi.ebay.com/12pcs-Kemet-Tantalum-Radial-Capacitor-10uf-35v-/120558841969?pt=LH_DefaultDomain_0&hash=item1c11ddf071
   
   
  For the same price, two MKC or MKP would have 10 times lower capacitance.


----------



## DarkskyZ

Hi all,
   
  I got my preassembled LC from Stephen 2 days ago with dual OPA627 class A 3.49mA bias option. It sound really good and I really like it.
   
  I have had a problem though. I asked for a stepped pot in place of the typical Alps 50k pot. When I received the LC, the pot looked warped, i.e. not perpendicular to the front panel and when turning it you could see it did not "turn round". Quite odd and annoying for the meticulous guy that I am while dealing with my gear.
   
  So as I asked to get the 50k Alps anyway in the package, I went on desoldering the odd pot and soldered the proper Alps in place. I am not skilled at soldering and it took me a few tries not to get cold solderings but I finally got them acceptable and continuity check was OK. So I powered it, and tried it (with my Apple iPod earbuds just to be safe) and my problem is that it seems that the pot it now fully up all the time. It has no action at all, sound is loud full time.
  So in place of a pot with warped nut I now have a nice looking pot with no action... Talk about a good move !
   
  So I yet checked the pot it self and I get good resistance readings (0 to 50k Ohms) on both channel just like on the stepped one. I am clueless now, what do you think I should check next ?
  My tools are as follows : digital multimeter, soldering iron and my eyes...
   
  Help very much appreciated as my now 2 days old LC is just waiting for an intervention right next to me with its guts out... 
   
  Thanks for reading.


----------



## BlaBlaBla

Quote: 





darkskyz said:


> Hi all,
> 
> I got my preassembled LC from Stephen 2 days ago with dual OPA627 class A 3.49mA bias option. It sound really good and I really like it.
> 
> ...


 

 Are soldering pins on your pot clean?
   
  You have to measure resistance between connections like stated on the picture. Also with a few different pot positions. If resistance does not exist or it is always the same value:
   
  1. Pot has been shorted.
   
  2. Solder suddenly connected two pins (pot - IN and pot - OUT) and now, pot is bypassed.
   
http://img248.imageshack.us/i/lovelycubepcb02.jpg/


----------



## DarkskyZ

Thanks for answering with clear instructions !
   
  The pot pins were not that clean but I put some solder on it before soldering to the board (don't know the English term when you apply a thin solder layer on metal).
   
  I measured resistance from the exact points you describe on the picture and I get varying values as it should be. Approx same value on both channels I should say.
   
  I know I messed up my solderings at first but now the readings are OK and resistance is varying depending on the pot rotation so it means that the solderings are right ? Right ?
   
  Any other reading I could take ?
   
  Thanks a million for helping me out


----------



## DarkskyZ

So here I am with a fixed LC 
   
  I got back to Stephen and he provided tremendous support with descriptive tests to do and all. Unbelievable at past 1:00AM for him !!!
   
  My problem was that for some reason I had broken the Alps common ground connection so it was just a matter of bridging 2 pins to a ground point and voilà ! Back up and running.
   
  I now have a nice LC with engraved aluminum front plate (first one or only one ?), sounding great and with a nice and smooth pot.
   
  Thank you BlaBlaBla for your help too !


----------



## BlaBlaBla

Quote: 





darkskyz said:


> So here I am with a fixed LC
> 
> I got back to Stephen and he provided tremendous support with descriptive tests to do and all. Unbelievable at past 1:00AM for him !!!
> 
> ...


 
   
  You are welcome!
  I am glad that the problem is solved! 
   
  Soon, another Lovely Cube PCB (with transformer) will arrive, and I will be able to assemble another Lovely Cube. (Package is at the customs office it should be here tomorrow. I can not wait...)
   
  Also, I have ordered matched MJE power, 2N5087/88 small signal transistors and PRP/Kiwame/Riken Ohm resistors. A lot of polystyrene and MKC stuff that I bought earlier for something else, but now I am going to use them for good. Only what I have missed is to find matched small signal transistors... But I will figure out something (probably find the closest pair with digital multimeter). I wonder how it will work (sound) when I put all this... 
   
  But I think that Stephen (if he is the person who was choosing all this parts for LC) made a good job.  It is hard to find other parts that will give you better synergy.


----------



## JiggaD369

Thanks!
   
  I think I'm ready to go ahead and place a order for my "GNARLY Mod Package!!!"  
	

	
	
		
		

		
		
	


	




 
	

	
	
		
		

		
		
	


	




 
	

	
	
		
		

		
		
	


	



   
  I have read almost all of the posts in this thread but I'm trying to consolidate it by basing all of the following by memory. This amp has impressed me so I think I'm going to keep it for a while and go ahead and mod it throughout. I want to keep it long term and want it to serve as a preamp for my active monitors also, so why not get the best sound out of it as possible?
   
  I'm also a newbie and this is my first time truly modding a PCB but I'm confident I can do it. Here we go...
   
  Bypass Input caps (C101, 102, 201, 202) with solid wire.
  Replace four PSU electrolytics with Panasonic FM (470uf/35v).
  Replace two electrolytics coupling the opamp with Elna Silmic II (470uf/25v - mounted horizontally).
  Replace two bypass caps for the above with K40Y Russian PIO (0.033uF/200V).
  Replace two 100pf caps by the opamp with polystyrene (same value).
  Replace four transistors in the buffer (BC550 & BC560) with Fairchild BC550C & BC560C (hfe >500).
  Replace four transistors in the buffer (BD139 & BD140) with Fairchild BD14016 & BD14016.
  Replace LM317 & LM337 with Fairchild LM317T &  LM337T.
  Replace ADJ caps with tantalum caps (10uf/25v)
  blablabla trimpot mod.
   
  Please feel free to comment.


----------



## francisdemarte

Let us know how the changes work out! 

If you don't own a set of precision tweezers, you might want to add it to your order. They help tremendously in pulling out some of the tighter packed parts!

Post some pictures when your done!


----------



## CrucifixationOfFaith

*JiggaD369* you should also think about :
- using ultrafast soft recovery rectifier diodes,
- bypassing the low pass band just after the pot,


----------



## JiggaD369

Quote: 





francisdemarte said:


> Let us know how the changes work out!
> 
> If you don't own a set of precision tweezers, you might want to add it to your order. They help tremendously in pulling out some of the tighter packed parts!
> 
> Post some pictures when your done!


 
   
  francis,
   
  I already have some and they came in handy trying to pull out those MKC bypass caps when I was trying to bypass the big blue caps. I usually avoid touching the leads of any components.
  
   
  Quote: 





crucifixationoffaith said:


> *JiggaD369* you should also think about :
> - using ultrafast soft recovery rectifier diodes,
> - bypassing the low pass band just after the pot,


 

 Cru,
   
  Would you mind pointing me towards which diodes (part numbers)? 
   
  And if you don't mind, what do you mean by "- bypassing the low pass band just after the pot,"?


----------



## BlaBlaBla

I have never thought about rectifier.
   
  I think, cheap BYV will be sufficient. Something with small reverse recovery time, and low forward voltage drop.
   
  I use BYV28-200.  (30ns, 0.6V - 0.8V)


----------



## CrucifixationOfFaith

*JiggaD369* desolder the C317 and C318 parts, bypass the R101 and R201 resistors.


----------



## BlaBlaBla

Quote: 





crucifixationoffaith said:


> *JiggaD369* desolder the C317 and C318 parts, bypass the R101 and R201 resistors.


 

 Why would you do that?
   
  Philips Tin Foil is almost like "Teflon", and polystyrene is a matter of taste. Tin Foil is more in front and slower, polystyrene is more wide and faster. If you remove 100pF capacitor you will allow very high frequency to pass into OPAMP that is useless (because we do not need frequency above 20 kHz)
   
  I do not see why would someone bypass only R101 and R201. For improvement I would remove ALPS POT and R101/R102 and put there high quality resistor (20 - 30k). But then I could not change the volume anymore.


----------



## JiggaD369

Sounds interesting but pushing the transistors into oscillation doesn't sound like a good idea.


----------



## CrucifixationOfFaith

... and that is why you should directly "back up" the op-amp with caps (low esr + foil).


----------



## Bacci

How do these layman Black Cube Linears (Chinese pcb but with mouser parts) compare to e.g. AMB M^3? Looking for my next DIY project with +/- 200$ to burn


----------



## ringer

My amp


----------



## Knusperfisch

Nice
	

	
	
		
		

		
			




   
  And you replaced the 4700µF and 470µF caps with what kind of caps? 
  Can you hear an improvement?


----------



## JiggaD369

When replacing the BD13916/14016 and LM317/337, does there need to be any matching done (as in the case of BC550C/560C)?


----------



## ringer

Quote: 





knusperfisch said:


> Nice
> 
> 
> 
> ...


 
   
  Thanks 
	

	
	
		
		

		
		
	


	



   
  The big caps is Epcos LongLife 4700uF 50V 105C. It is good caps I think. I didn't try Nichicon Gold Tune 5600uF 50V, because I doubt that it's real Nichicon (maybe I'm paranoid 
	

	
	
		
		

		
		
	


	




).

   
  The 470uF caps is Epcos 35V 105C. I've change them because of heating. I think that 85C is not enough. It is not the best choice, but I didn't find any better in local stores. I didn't notice difference in sound compared to Elna.

   
  Also I've used another BD transistors.


----------



## ringer

Quote: 





jiggad369 said:


> When replacing the BD13916/14016 and LM317/337, does there need to be any matching done (as in the case of BC550C/560C)?


 

 There is no need to replace LM317/337 I think.
   
  For BD139-16/140-16 it is better to find with 5% hFE deviation.


----------



## DarkskyZ

Here are other pictures : http://tinyurl.com/5wtyqbs
   
  Got it last week, fully assembled. This is my very first amp but I really love the sound I get !
   
  Thanks Stephen


----------



## TheKisho

I'm just about to order the kit for this amp.  I want an op-amp better than the one that comes with the amp and better then the class-A mod dual OPA627.  I'm new to op-amps.  Currently I'm using a Indeed headphone amp (same as bravo hybrid) with a clear, flat, uncolored and transparent Siemens ECC88 A-frame tube (with IRF 630 output MOSFET).  [I'm sure nobody here has ever mess with that sort of stuff.  (That tube should probably sound similar in another device)].  I love to keep this sound, but I want something that is solid state that I can through in my bag and take with me without worrying about damaging tubes.  I'm thinking about the LT1364 and I want to know if it fit the bill for what I'm looking for, and how do I make it class-A biased?
   
  The ideal sound I want from an op-amp:
  -A nice big soundstage that matches my headphones nicely
  -A nice flat balanced frequency response that has good extension on both the high end and on the low end
  -Very detailed and analytical
  -A tad bit weighty
  -Transparent and clear
  -Good amount of low level detail (sensitive)
  -Good Imaging
  -Sibilance is alright only if it's in the source file and it's being true to the source
  -Keep music feeling natural & musical while being accurate to source
  -Fast, but not too fast to seem unnatural or too slow to be muddy
  -NOT boomy, bloated, bassy, colored, congested, gentle, grungy, honky, mellow, layed back, muddy, muffled, smeared, warm, veiled, or tubby.
   
   
  If this op-amp doesn't match ^, do you know any one that will work better for the task.
   
  P.S.  I'm into AKG headphones, so I'd really enjoy the input from fellow AKG people (all opinion welcome, but don't be shy AKG people (and if you are one, please say so in your post)).
   
  P.P.S.  What is the common basic mods and upgrades that most people here do to their amp these days.


----------



## ringer

Quote: 





thekisho said:


> I'm just about to order the kit for this amp.  I want an op-amp better than the one that comes with the amp and better then the class-A mod dual OPA627.  I'm new to op-amps.  Currently I'm using a Indeed headphone amp (same as bravo hybrid) with a clear, flat, uncolored and transparent Siemens ECC88 A-frame tube (with IRF 630 output MOSFET).  [I'm sure nobody here has ever mess with that sort of stuff.  (That tube should probably sound similar in another device)].  I love to keep this sound, but I want something that is solid state that I can through in my bag and take with me without worrying about damaging tubes.  I'm thinking about the LT1364 and I want to know if it fit the bill for what I'm looking for, and how do I make it class-A biased?
> 
> The ideal sound I want from an op-amp:
> -A nice big soundstage that matches my headphones nicely
> ...


 

 I'm listen LC with MBQuart 450 PRO. Don't know how the sound would be with AKG. But MBQuart has the best sound with the 2134 (stock OPAMP). The most comfort and slightly more dark sound with 627 class A mod. I also have tube amplifier Laconic HA-02, and I think LC with stock OPAMP sounds more naturally. But tubes is tubes, your favorite songs which gives you maximum pleasure with your tube amp will never sounds exactly the same way with transistor amp.


----------



## BlaBlaBla

Quote: 





thekisho said:


> I'm just about to order the kit for this amp.  I want an op-amp better than the one that comes with the amp and better then the class-A mod dual OPA627.  I'm new to op-amps.  Currently I'm using a Indeed headphone amp (same as bravo hybrid) with a clear, flat, uncolored and transparent Siemens ECC88 A-frame tube (with IRF 630 output MOSFET).  [I'm sure nobody here has ever mess with that sort of stuff.  (That tube should probably sound similar in another device)].  I love to keep this sound, but I want something that is solid state that I can through in my bag and take with me without worrying about damaging tubes.  I'm thinking about the LT1364 and I want to know if it fit the bill for what I'm looking for, and how do I make it class-A biased?
> 
> The ideal sound I want from an op-amp:
> -A nice big soundstage that matches my headphones nicely
> ...


 
   
  Maybe you need too much. 

 You should try OPA2107. If it is too bright and wide then you can put it into A class and get stronger mid range. OPA627 is too expensive.


----------



## BlaBlaBla

Quote: 





ringer said:


> Thanks
> 
> 
> 
> ...


 

 Agree. I also think that stock capacitor is far from genuine nichicon. But it works. At least for now.  You do not need 85°C on input because capacitors are large and have good heat dissipation.  After 2 hours of playing they are warm because rest equipment, but I think below 45°C.
   
  Those capacitors between regulators and transistors are something else. I think that stock Elna (85°C) are far from "optimal choice". After 2 hours of playing on easy headphones temperature raises above 50°C which is close to their (85°C) rated temperature. And now, it is winter in my country. What will be when summer comes?
  I put there Panasonic FM/FC.
   
  Epcos (genuine) makes are excellent capacitors. Long life and very robust. If they are made by genuine Epcos,  they will last much longer than other parts in your amplifier.
   
  But beware! Maybe you have problems with rectifier? If input capacitors are too warm after few minutes of work, then you should check rectifier diodes. Maybe they are leaking too much and your capacitors are negatively polarised for a short time. I always check diode resistance in both ways. (I know this is not good enough but it tells me if diode is a bad product or not). In open direction It has to be in miliohm range, and in a close direction in a megaohm range. Input capacitors have to be cold for a long time, after turn on. And became warm only because of heat of rest equipment (pick up the heat - not making it).


----------



## BlaBlaBla

PRPs are soldered.
  Now I am waiting for MJE, 10k signal resistors (I am so stupid. I forgot to buy them when I was buying the rest...), Vout capacitors (on regulator), input capacitors (signal) and 10R carbon resistors for output.
   
  I also bought bigger heatsinks because I do not believe in the fairytale about "it has to be warm because it sounds better". My ass. I just do not believe in that audiophile crap. In a power network, usually, when something becomes too hot and close to the limit, it dies. In a very short time. Why would Lovely Cube be an exception? 
   
  Picture of soldered parts on PCB will be here, when I come home.


----------



## JiggaD369

Will a 35MM height cap fit for the big PSU caps?


----------



## TheKisho

Quote: 





ringer said:


> I'm listen LC with MBQuart 450 PRO. Don't know how the sound would be with AKG. But MBQuart has the best sound with the 2134 (stock OPAMP). The most comfort and slightly more dark sound with 627 class A mod. I also have tube amplifier Laconic HA-02, and I think LC with stock OPAMP sounds more naturally. But tubes is tubes, your favorite songs which gives you maximum pleasure with your tube amp will never sounds exactly the same way with transistor amp.


 

 I hear they [OPA2134] are muddy, bloated and have limited sound stage, I rather avoid it [The OPA627 I hear kind has a muddled mid range at times as well].  The AKGs would make the flaws dead obvious as well.
  It's a hybrid.  Beside the tube doesn't add much to the sound (unlike the cheap chinese 6N11).  While I cannot get the exact same sound I can achieve something similar with a good op-amp and a much better amp (the original indeed circuit isn't perfect).
   
   
   


  Quote: 





> Originally Posted by *BlaBlaBla* /img/forum/go_quote.gif
> Maybe you need too much.
> 
> You should try OPA2107. If it is too bright and wide then you can put it into A class and get stronger mid range. OPA627 is too expensive.


 

 Maybe.  But I would like to get close to that on my first few attempts.  Playing it picky usually helps to get the majority of the way there.
   
  I'm fine if it's bright.  Does it have good extension of highs and lows?  Can you describe it any farther?  Is it drop in able without pin rerouting or biasing to preventing being unstable oscillating?  I don't like the OPA627 or most BB op-amps how they are described, they all seem to be described as sounding layed back, slow, bloated, and colored.
   
   
  I might get a LT1364 and OPA2107 for starters.  Can somebody tell me how to bias the LT1364 for class-A with bias that is just right for it (or my likes).  Sorry, I'm new...
   
  Any more suggestions before I start buying? [Post #490]


----------



## ringer

Quote: 





blablabla said:


> But beware! Maybe you have problems with rectifier? If input capacitors are too warm after few minutes of work, then you should check rectifier diodes. Maybe they are leaking too much and your capacitors are negatively polarised for a short time. I always check diode resistance in both ways. (I know this is not good enough but it tells me if diode is a bad product or not). In open direction It has to be in miliohm range, and in a close direction in a megaohm range. Input capacitors have to be cold for a long time, after turn on. And became warm only because of heat of rest equipment (pick up the heat - not making it).


 

 No, there is no heating problem with input capacitors. They are slightly warm.


----------



## CrucifixationOfFaith

Is there any justification in using BD140/BD139 and not their equivalents with lower voltage ratings ?


----------



## BlaBlaBla

Quote: 





thekisho said:


> I hear they [OPA2134] are muddy, bloated and have limited sound stage, I rather avoid it [The OPA627 I hear kind has a muddled mid range at times as well].  The AKGs would make the flaws dead obvious as well.
> It's a hybrid.  Beside the tube doesn't add much to the sound (unlike the cheap chinese 6N11).  While I cannot get the exact same sound I can achieve something similar with a good op-amp and a much better amp (the original indeed circuit isn't perfect).
> 
> 
> ...


 

 I think that BB opamps are the most stable and easiest to drive in the class A. I tried five of them and never had any problem. AD opamps are just opposite they are very sensitive to power supply and capacitors.
  OPA 2107 is more wide than OPA 627 but has less pronounced vocals. Laid back? Depends. On your entire setup and on type of music that you like to listen to. With AKG K701, OPA2107 has less synergy than with ATH or Grado. That is because AKG K701 have enormous soundstage and it becomes too wide. With Grado, situation is opposite.
 I will say (with ATH) that OPA2107 is excellent for listening to music genre like Enya, soundtracks made by Jablonsky and something that needs big and spacey soundstage. Here OPA627 does not come even close.
  But... If someone wants to listen to rock, violin concerts, guitar concerts where there is need for concentration on one instrument and where "magic warmth" must exist - OPA627 wins.
  Also I tried AD797 and was driving it successfully (without oscillation), but it is not worth time and effort. Too sterile and to plain (without soul). This opamp is not good for amplifiers, but for DAC (where high precision is most important fact). After disappointment with AD797 I did not try another AD. I heard that all ADs behave the same. They sound clinically (too much). Not my type...
   
  Right now I have plans for using a new LME49720HA (to put into new amplifier). But I do not have big expectation. This opamp has good technical specification. But quality of sound does not relly only on pure technicall spec. All opamps today are far above that we need for listening to music. Sometimes, very slow opamp can be better, than ultra fast one. Do not judge the opamp on technical spec. It depends where you want to put it, and what do you want from it.


----------



## francisdemarte

My advice is to stop reading all these opinions and listen to the amp with stock op amp first then decided for yourself. The sound of an amp is more than the just the opamp.


----------



## ringer

Quote: 





francisdemarte said:


> My advice is to stop reading all these opinions and listen to the amp with stock op amp first then decided for yourself. The sound of an amp is more than the just the opamp.


 

  
  Agree.


----------



## BlaBlaBla

Quote: 





ringer said:


> Agree.


 

 I do not agree.  Stock opamp is mainstream crap.
  Avoid at all costs.


----------



## TheKisho

Quote: 





francisdemarte said:


> My advice is to stop reading all these opinions and listen to the amp with stock op amp first then decided for yourself. The sound of an amp is more than the just the opamp.


 

 True.  An amp adds it's own sound and character but a tube or an op-amp is still 1/3th of the sound.  If you have a poor sounding op-amp or tube your going to hear it.  Knowing my own tastes I most likely will not like the stock sound.


----------



## gwikse

There are too many opinions on these things but I`m going to start with the stock parts since there are no "only op-amp" sound. The Op-amp has a large impact on sound yes but the sound will vary from one type of amp to another. Having a swappable op-amp socket makes it easy to swap out and more often than not I have been surprised at wich op-amps have led to the best sound in different equipment. A piece of tape covering the top of the op-amp makes a blind test easy. And op-amps we can afford having lying around 
   
  Ordered my lovely cube today. Will make a balanced amp with two boards and a stepped attenuator. The amp will also be used as a pre-amp in my main rig. Will be paired with: BuffaloII DAC, IcePower1000ASP mono`s, Audiophysic Virgo V speakers. 3dmodel of the lovely cube will be posted when done hopefully later today.


----------



## ringer

Quote: 





blablabla said:


> I do not agree.  Stock opamp is mainstream crap.
> Avoid at all costs.


 

 I like stock op amp. Beautiful sound with my headphones. Besides, I doubt that Lehmann Audio think about saving money on op amps when they made Black Cube. They made one of the most famous headphone amplifier...


----------



## ringer

Quote: 





gwikse said:


> There are too many opinions on these things but I`m going to start with the stock parts since there are no "only op-amp" sound. The Op-amp has a large impact on sound yes but the sound will vary from one type of amp to another. Having a swappable op-amp socket makes it easy to swap out and more often than not I have been surprised at wich op-amps have led to the best sound in different equipment. A piece of tape covering the top of the op-amp makes a blind test easy. And op-amps we can afford having lying around
> 
> Ordered my lovely cube today. Will make a balanced amp with two boards and a stepped attenuator. The amp will also be used as a pre-amp in my main rig. Will be paired with: BuffaloII DAC, IcePower1000ASP mono`s, Audiophysic Virgo V speakers. 3dmodel of the lovely cube will be posted when done hopefully later today.


 

 Оne thing I'm absolutely certain  - sound signature of op amps is nothing depends on sound signature of headphones.
  If headphones is bassy, then you probably like OPA2111. If it is bright, then you might prefer OPA627... But the stock one is good


----------



## JiggaD369

I think the end result of the sound signature is the sum of ALL parts.
   
  Sextetts are known to have the best midrange known to man kind and my setup does a fine job of doing everything else right.


----------



## ringer

Quote: 





jiggad369 said:


> I think the end result of the sound signature is the sum of ALL parts.
> 
> Sextetts are known to have the best midrange known to man kind and my setup does a fine job of doing everything else right.


 


  Noob question from Russia - what is Sextetts?


----------



## BlaBlaBla

Quote: 





ringer said:


> Noob question from Russia - what is Sextetts?


 
   
  AKG Sextett. Famous headphones from AKG. Almost like AKG K1000.
   
   
  Lehmann Cube linear is the most famous headphone amplifier because:
   
  - it is German (quality)
  - it has simple circuit (low losses)
  - it can handle AKG (people think that it is the best)
  - it can be easily bought (Yamamoto can not)
   
  - and its opamp sucks


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> I think the end result of the sound signature is the sum of ALL parts.
> 
> Sextetts are known to have the best midrange known to man kind and my setup does a fine job of doing everything else right.


 

 Agree. Even signal resistor can change sound signature...
   
   
  But stock OPA 2134 is crap...


----------



## ringer

Quote: 





blablabla said:


> Agree. Even signal resistor can change sound signature...
> 
> 
> But stock OPA 2134 is crap...


 

 What is the best OPA in your opinion?


----------



## gwikse

getting there... pheu. Loads of layors...


----------



## BlaBlaBla

Quote: 





gwikse said:


> getting there... pheu. Loads of layors...


 
   
  I do not see stock BB OPA2134! This is excellent work!
   
  Now we need someone who has good CNC machine to make a PCB board. I will buy two PCBs.


----------



## JiggaD369

Quote: 





blablabla said:


> Agree. Even signal resistor can change sound signature...
> 
> 
> But stock OPA 2134 is crap...





   
  That's why I swapped it for 2107 (until I get a Burson in the far future)!


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> That's why I swapped it for 2107 (until I get a Burson in the far future)!


 

 Burson is excellent.
   
  Here is my PCB... http://www3.picturepush.com/photo/a/5133076/img/5133076.jpg
   
  I started with red resistors. Now it is time to put there a few pink one, and then some big green made in last decade. I like the old school carbon resistors in output. Also I was not satisfied with voltage drop over diodes, and with their quality (one felt apart), so I found a better solution. It was pity that this diodes could not fit in the holes so I had to improvise. And that is my strong point. See it - improvise - conquer.
   
  I left few resistors from the stock package, just to remind me how stock resistors look like.


----------



## gwikse

Nice 
   
  I have to be a little creative myself. First and foremost around the opa socket. But I think the easy solution to this is to mount the capacitors angled underneath the pcb.


----------



## CrucifixationOfFaith

op-amp rolling ? Sounds lame.
Let's take it to another level - transisotr rolling. 

http://www.diamondstar.de/jisbos/jisbos_partslist.html


----------



## JiggaD369

Quote: 





crucifixationoffaith said:


> op-amp rolling ? Sounds lame.
> Let's take it to another level - transisotr rolling.
> 
> 
> ...


 
   
  Sorry I'm new to transistors so still trying to learn. Are those all compatible replacements in the LC?


----------



## BlaBlaBla

Quote: 





gwikse said:


> Nice
> 
> I have to be a little creative myself. First and foremost around the opa socket. But I think the easy solution to this is to mount the capacitors angled underneath the pcb.


 

 Tried before. Was not successful. It is hard to place some capacitors underneath PCB. Especially some MKP caps. I have big problems with ERO caps. They are like small boxes.


----------



## gwikse

Quote: 





blablabla said:


> Tried before. Was not successful. It is hard to place some capacitors underneath PCB. Especially some MKP caps. I have big problems with ERO caps. They are like small boxes.


 


  I`ll design the case around the finished (in 3d first) board. So as long as it is possible to get to the solder joints (wich are on both top and bottom of the pcb) it should not be a problem unless I am missing something?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Sorry I'm new to transistors so still trying to learn. Are those all compatible replacements in the LC?


 

 Almost everything that has similar technical data. Or bigger. Most important things are VCBO, VCEO, VEBO, IC because they will prevent you from burning things right after "turn on".
  Next are VCB, VCE etc... "saturation" if you want to do fine tuning on your amp (I do not have enough patience to do that and just use transistor with similar specification.) And for sound important are hFE gain and linearity, frequency and noise figure. After that important are drawings that tell you where goes gain within heat and collector current. (Probably, I forgot something...)
   
  As far as I know, BC109C and BC179C work flawlessly. But have to be careful because they have lower VCBO, VBEO, VCEO.
   
  2SA1015 and 2SC1815 also work (they have bigger specs so you will not fry anything), but it is pain in the ass to solder them properly because different pin out. And also pain in the ass to find good (should I say "genuine") parts. Well, at least within specification...
   
  2N5087 and 2N5088 I did not try and I would avoid them because low VEBO (3V). I mean I did not make any measurements to be shure that VEBO will not go above 3V... Besides you have to watch over Ic current because they are small signal transistors with Ic maximum 20 mA. So you will have to put in a circuit resistors with bigger value to limit current.
   
  And... If you fail with BC transistors, your headphones will get almost 1.5V DC signal. Which is, if you do not have Sextetts or something with 600ohm resistance, quite high and will roast your headphone coils like chicken. You have to be sure, and do a lot of testing, before listening. Same thing goes with opamp. If opamp fails, then only what you can do, is to call nearest seller and ask him if he has another headphones in stock. I did that half year ago. But I am not eager to do that again... :/
   
  Matrix M Stage had relay that was able to limit incoming signal. But that relay was on input, not on output... Again barbecue... LOL. Probably someone was not sure if people would plug amplifier (RCA) into wall socket instead sound card or mp3 player...


----------



## BlaBlaBla

Quote: 





gwikse said:


> I`ll design the case around the finished (in 3d first) board. So as long as it is possible to get to the solder joints (wich are on both top and bottom of the pcb) it should not be a problem unless I am missing something?


 

 Forgot to say, I use stock case...
   
  But you gave me good idea. I have some metal boxes in the cellar... Maybe I could use them an put there bigger transformer (100VA) instead stock one (30VA)... Interesting.


----------



## JiggaD369

Ok the more I read about transistors, the more I'm getting confused.
  I decided to go with MJE243/MJE253 then read that it will not go well with high impedence phones like the Sextett (600). 
	

	
	
		
		

		
		
	


	



   
  What is the best option for the replacing the BD139/140?


----------



## ringer

Quote: 





jiggad369 said:


> Ok the more I read about transistors, the more I'm getting confused.
> I decided to go with MJE243/MJE253 then read that it will not go well with high impedence phones like the Sextett (600).
> 
> 
> ...


 

 You can try old Soviet germanium transistors GT402-GT404 (ГТ402-ГТ404 in Russian) instead BD140-BD139. I don't know how they change the sound, but they change for sure. I guess that sound will be smoother, more like tubes. But max temperature has to be 50...55°С.


----------



## gwikse

The model is uploaded and can be downloaded through google sketchup 8`s model finder. Search for "Lovely cube".
  Some components are not in the model as I will not use them.


----------



## BlaBlaBla

Quote: 





ringer said:


> You can try old Soviet germanium transistors GT402-GT404 (ГТ402-ГТ404 in Russian) instead BD140-BD139. I don't know how they change the sound, but they change for sure. I guess that sound will be smoother, more like tubes. But max temperature has to be 50...55°С.


 


  Too big.


----------



## BlaBlaBla

Quote: 





gwikse said:


> The model is uploaded and can be downloaded through google sketchup 8`s model finder. Search for "Lovely cube".
> Some components are not in the model as I will not use them.


 
   
  I downloaded schematic. Excellent work.
   
  You should remove input capacitors (ERO MKC 22nF) because you have replaced Siemens 1.5uF (big blue one) capacitors with wire. Entire signal goes through wire. 22nF caps are useless then.


----------



## JiggaD369

Is anyone selling the PCB just by itself?


----------



## gwikse

Quote: 





blablabla said:


> I downloaded schematic. Excellent work.
> 
> You should remove input capacitors (ERO MKC 22nF) because you have replaced Siemens 1.5uF (big blue one) capacitors with wire. Entire signal goes through wire. 22nF caps are useless then.


 
  Thank you.
   
  All the input caps will be removed or all inserted in my project. However I think the better solution to using wire to bypass them is to solder the wire directly from the input rca. I just stopped half way through making the cap itself 
   
  Edit: I`m going doal mono balanced


----------



## francisdemarte

jiggad369 said:


> Is anyone selling the PCB just by itself?




Stephan the seller of the LC also sells the unpopulated board for $15 or $18.


----------



## francisdemarte

gwikse said:


> Thank you.
> 
> All the input caps will be removed or all inserted in my project. However I think the better solution to using wire to bypass them is to solder the wire directly from the input rca. I just stopped half way through making the cap itself
> 
> Edit: I`m going doal mono balanced




Great idea flipping the 2nd board over. What are you thinking of using for a 4 ch attenuator?


----------



## gwikse

I have a DACT CT2 and a CT3 input selector.


----------



## JiggaD369

Quote: 





francisdemarte said:


> Quote:
> 
> 
> 
> ...


 

 Francis,
   
  I don't know if he did but he does not anymore.


----------



## CrucifixationOfFaith

jiggad369 said:


> Is anyone selling the PCB just by itself?




You only need to redraw the schematics and pcb layout that are already given, the rest is easy. 
Will do it with a little bit of free time (probably next week).


----------



## BlaBlaBla

Quote: 





crucifixationoffaith said:


> Quote:
> 
> 
> 
> ...


 
   
  Well it is not so easy and cheap. If you want good PCB (machine-made) then you have to pay a lot money. Manufacturer will have the same costs if he does one PCB or many PCBs (because of mold that has to be done before printing).
   
  In my country, for good quality, machine made PCB, that you have drawn on your own, and size 10x10 cm, you have to pay 300 HRK (55 USD). For exact same type, but 20 PCBs, you have to pay 1000 HRK (190 USD)...


----------



## CrucifixationOfFaith

It is not easy if you are building a circut from scratch, the optimizaton process can go on and on..
If you are looking for a company that will do e.g. 10 mil traces then the prices will be high.
You have to be insane or at least have to be testing a prototype to order a single pcb.


----------



## JiggaD369

I just want two.


----------



## ringer

Has anyone try discrete op-amps with LC? What do you think about http://www.partsconnexion.com/DEXA-73728.html ?


----------



## gwikse

I plan to use audio gd opa sun v2 in mine. I have used some regulators from NewclassD (Dexa) with good results so I would think they are good.
  From what I can see on the pictures it may fit into the slot between the caps since it is narrower than the sun V2. You will have to make a hole in the cover for it though. Otherwise you could use an extention cord as with the sun V2.
   
  How well it will work in the amp is another matter though. Since the amp runs so hot I have my doubts. My chassis will be different as well as the placement of the TO220`s
   
  edit: as I suspected. the dexa opa fits in between the caps. The height is lower, the width is 15mm vs 24mm and power consumption is also only 1/5th of the audio gd unit.


----------



## ringer

DEXA is 32mm height. It may fits well without extention chord... Why do you want to use audio gd? What is the reason of your good expectations?


----------



## gwikse

I use what I allready have. The smd based solutions came later. I may well buy dexa`s as well later on, but they cost more than double that of the audio-gd`s.
   
  What is the internal height of the standard chassis?


----------



## JiggaD369

Quote: 





gwikse said:


> I plan to use audio gd opa sun v2 in mine. I have used some regulators from NewclassD (Dexa) with good results so I would think they are good.
> From what I can see on the pictures it may fit into the slot between the caps since it is narrower than the sun V2. You will have to make a hole in the cover for it though. Otherwise you could use an extention cord as with the sun V2.
> 
> How well it will work in the amp is another matter though. Since the amp runs so hot I have my doubts. My chassis will be different as well as the placement of the TO220`s
> ...


 

 Gwiske,
   
  What kind of setup are you going for (resistors, caps, volume pot., transistors, etc)?


----------



## gwikse

I will have to see what I get in the kit when it arrives but I allready have some changes in mind.
   
  C305 - Vishay BC 2200uF 63V x 3 custom mounting
  C306 - Vishay BC 2200uF 63V x 3 custom mounting
  Wima MKS02 bypass caps all around (I have a lot of them).
  Rectifier diodes will be BYV27-150 (I have a lot of them).
  I have a few LT317AT and LT337AT for this project as well.
  The project is wip so any suggestions will be appreciated.
  At this moment though I have just bought the kits (not yet recieved them).
   
  "iPimped" is my starting point.
   
  Quote: 





> Bypass Input caps (C101, 102, 201, 202) with solid wire.
> Replace four PSU electrolytics with Panasonic FM (470uf/35v).
> Replace two electrolytics coupling the opamp with Elna Silmic II (470uf/25v - mounted horizontally).
> Replace two bypass caps for the above with K40Y Russian PIO (0.033uF/200V).
> ...


 
   
  I had hoped I could use my DACT CT2-4-10K to replace the alps 50K pots but not sure if this is possible. Again the DACT is already in my system, but is currently passive together with a DACT CT3-5-4 input selector wich will also be used.
  Two Audio GD OPA Sun V2 will proborably be used, but opa rolling with a lot of contenders will happen at some point.
   
  Chassis will be custom made with the main difference from the norm will be that the orientation of the boards will be vertical so that they will not block natural airflow.
   
  WIP
   
  The uploaded sketchup model is updated as I go


----------



## JiggaD369

Awesome!
   
  Where did you big the kit? Is it assembled?
   
  Also, mind sharing that custom mounting for the big two caps? 
   
  As for the pot, what do you think about this?
   
http://cgi.ebay.com/TKD-50K-2CP-601-Riken-Elma-Noble-2A3-Tango-300B-EL84-AB-/220742911787?pt=LH_DefaultDomain_0&hash=item33654d872b#ht_3812wt_1143


----------



## CrucifixationOfFaith

gwike said:
			
		

> *Replace two electrolytics coupling the opamp with Elna Silmic II (470uf/25v - mounted horizontally).*



I wouldn't bother with Silmica especially with the II, the 'first' one is quite nice and what you want to put is quite flashy ( low and high tones are dominant). Stick with something secure like BG STD, you can also try Panasonic Pureism.

Guys, where can I get the BD139 made by Philips ?
Didn't have any problems in obtaining BD137/138/140 and the BC's from this manufacturer.


----------



## LingLing1337

I saw a few posts early in this thread about driving Head-Direct orthos (HE-5 to be specific) with a Lovely/Black Cube. Any thoughts on this subject? Does this little design really have enough juice to do the HE-5 or HE-4 justice?


----------



## gwikse

Has anyone tested without the rectifier smoothing caps and resistors?
  My experience with the byv27-150 is that it is better without caps at least as this does not bring AC past the diode. I think I`ll rather use the mounting holes for more byv27`s
  
  Quote: 





jiggad369 said:


> Awesome!
> 
> Where did you big the kit? Is it assembled?
> 
> ...


 

 Thanks still working on it.
   
  The cap mounting will be uploaded when I have gotten a little further along in the model.
   
  I have not tested that pot, but Audio Note usually know what they are doing...
   
   
  Quote: 





			
				CrucifixationOfFaith said:
			
		

> /img/forum/go_quote.gif
> 
> 
> 
> ...


 


  Thanks for the input. I`ll see if I can find some of your suggestions.


----------



## francisdemarte

> I saw a few posts early in this thread about driving Head-Direct orthos (HE-5 to be specific) with a Lovely/Black Cube. Any thoughts on this subject? Does this little design really have enough juice to do the HE-5 or HE-4 justice?




headfonia.com reviewed the HE-6 on the Matrix M-Stage and it powered them with no problem, so the Lovely Cube should also no issues powering the Head Direct orthos either.

http://www.headfonia.com/hifiman-he-6-first-impression/2/


----------



## LingLing1337

That's pretty cool. Good to know there's a cheap backup plan if my Peachtree doesn't have the guts for it.
   
  EDIT: Has anyone asked lasercollection about the case and transformer he offers with the completed kit? What price might I be looking at?


----------



## gwikse

The kit was bought from lasercollection`s site. It has case, transformers, op-amps and completed amps.
   
  Edit: forgot the link... http://www.alicemagicbox.com/lasercollection/lovelycube.html#02
  
  Quote: 





jiggad369 said:


> Awesome!
> 
> Where did you big the kit? Is it assembled?
> 
> ...


 
    


  
  Quote: 





			
				LingLing1337 said:
			
		

> /img/forum/go_quote.gif
> 
> That's pretty cool. Good to know there's a cheap backup plan if my Peachtree doesn't have the guts for it.
> 
> EDIT: Has anyone asked lasercollection about the case and transformer he offers with the completed kit? What price might I be looking at?


----------



## JiggaD369

OH so you bought the assembled kit and your desoldering/soldering parts on it?


----------



## gwikse

The kit comes as a kit. All parts need to be soldered onto the pcb. The finished board is a finished board with all components soldered.
   
  Stephen?


----------



## TheKisho

Does anyone know if the seller, will sell any of his "Signal Wire (White)" [Thermax M27500-22RC2S09] as seen on his site for a price?


----------



## BlaBlaBla

I tried DALE carbon resistors on output. And Allen Bradley... Allen Bradley really kicks ass! They give interesting sound. More laid back. On good recorded songs they are able to give warmth and mellow sound. So relaxing, so sweet... I could listen to music all day... )) I think in a signal path good metal film is a must, but in power path (output - 10R) carbon resistors have "something". At least on ATH AD900...  I think, I am going to buy tube amplifier...


----------



## BlaBlaBla

Quote: 





lingling1337 said:


> That's pretty cool. Good to know there's a cheap backup plan if my Peachtree doesn't have the guts for it.
> 
> EDIT: Has anyone asked lasercollection about the case and transformer he offers with the completed kit? What price might I be looking at?


 


  Talema 30VA - about 40 USD
   
  Case - about 42 USD.


----------



## gwikse

Quote: 





blablabla said:


> I tried DALE carbon resistors on output. And Allen Bradley... Allen Bradley really kicks ass! They give interesting sound. More laid back. On good recorded songs they are able to give warmth and mellow sound. So relaxing, so sweet... I could listen to music all day... )) I think in a signal path good metal film is a must, but in power path (output - 10R) carbon resistors have "something". At least on ATH AD900...  I think, I am going to buy tube amplifier...


 


  Sounds nice.
 Have been thinking about allen bradley resistors. Think I`ll order some.
   
  Have you tested a tube buffer? I love having the option of splitting the signal from my dac through a tube buffer for those "roomy live recordings". While most of the time I feel the tubes become a filter.


----------



## BlaBlaBla

Quote: 





thekisho said:


> Does anyone know if the seller, will sell any of his "Signal Wire (White)" [Thermax M27500-22RC2S09] as seen on his site for a price?


 

 I think he would not. But wire is not so expensive (0.5m length that you need in your amp).
   
http://cgi.ebay.com/99-999-0-4mm-Solid-Silver-Wire-Teflon-PTFE-Insulation-/280578389276?pt=UK_Computing_CablesConnectors_RL&hash=item4153c6751c
   
  It does not have to be MIL spec. wire.


----------



## gwikse

http://cgi.ebay.com/26-AWG-Solid-Silver-wire-unbleached-cotton-insulation-/160322322873?pt=LH_DefaultDomain_0&hash=item2553f481b9


----------



## BlaBlaBla

Quote: 





gwikse said:


> Sounds nice.
> Have been thinking about allen bradley resistors. Think I`ll order some.
> 
> Have you tested a tube buffer? I love having the option of splitting the signal from my dac through a tube buffer for those "roomy live recordings". While most of the time I feel the tubes become a filter.


 
   
  I have not tested tube buffer. But I think that I have to think about good tube amplifier... Or hybrid (tubes and transistors).
   
  I would like to know if someone has good advice. I would like to buy PCB, and rest, do it on my own... 
  
  Allen Bradley are excellent resistors, but with carbon resistors there is always problem that they might give "too soft and slow" sound signature. But that depends on all components in the amplifier.
  Now I know what to do if amplifier sounds too bright or sterile. Just put a few carbon resistors on output and magic appears.. ))


----------



## BlaBlaBla

Quote: 





gwikse said:


> http://cgi.ebay.com/26-AWG-Solid-Silver-wire-unbleached-cotton-insulation-/160322322873?pt=LH_DefaultDomain_0&hash=item2553f481b9


 

 Shipping costs are almost 40 USD.


----------



## JiggaD369

Quote: 





blablabla said:


> I have not tested tube buffer. But I think that I have to think about good tube amplifier... Or hybrid (tubes and transistors).
> 
> I would like to know if someone has good advice. I would like to buy PCB, and rest, do it on my own...
> 
> ...


 

 Which AB resistors are you referring to?
   
  I plan to use the FlukeLL method where you wire multiple resistors in parallel to equal 10 ohm.
   
  For a tube amp, I've always wanted to build a Aikido amp.
   
http://glass-ware.stores.yahoo.net/newhardware.html


----------



## lyramax

The LC seller now offers a LC premium version, but its extra is not worth the price premium he's charging.


----------



## JiggaD369

FINALLY!
   
  Ok after two days of fussing and trying to translate CHinese, I finally convinced a seller in China to sell me couple LC PCBs.
   
  If anyone is interested in a group buy, please let me know so I can find out the price for you. MIght as well order them together instead of paying the crazy shipping cost for each PCB. I'm thinking about placing a order next week so ya'll have plenty of time to think.


----------



## BlaBlaBla

Quote: 





lyramax said:


> The LC seller now offers a LC premium version, but its extra is not worth the price premium he's charging.


 

 Agree. Now I am waiting a few things more, and when they come, I will be able to complete my second Lovely Cube.


----------



## gwikse

Thats it for today. Preview. Good night.


----------



## francisdemarte

You guys might also want to consider the Jay car or Silicon Chip amp. 

http://www.head-fi.org/forum/thread/501046/first-impressions-lovely-cube-semi-diy-amp-lehmann-black-cube-linear-clone/195

Very similar to the LC topology but the opamp has feedback and the power supply is on a separate board.


----------



## lyramax

Quote: 





t.iizuka said:


> ...
> 
> RCA Connector
> 
> ...


 

 In running a stereo system setup test CD I just discovered the L+R RCA on my LC are also reversed (the red connector is actually the left channel).  It might be a recurrent mistake in the initial bunch of LCs sold fully pre-assembled.


----------



## T.IIZUKA

Quote: 





lyramax said:


> In running a stereo system setup test CD I just discovered the L+R RCA on my LC are also reversed (the red connector is actually the left channel).  It might be a recurrent mistake in the initial bunch of LCs sold fully pre-assembled.


 
   

  The initial product that seems to have been reversed.
  Recent finished product there is no problem. (confirmed with my friend to buy)
   
   I just use it without processing.
  If I knew then that the opposite problem.


----------



## T.IIZUKA

Quote: 





lyramax said:


> In running a stereo system setup test CD I just discovered the L+R RCA on my LC are also reversed (the red connector is actually the left channel).  It might be a recurrent mistake in the initial bunch of LCs sold fully pre-assembled.


 
   

  The initial product that seems to have been reversed.
  Recent finished product there is no problem. (confirmed with my friend to buy)
   
   I just use it without processing.
  If I knew then that the opposite problem.


----------



## Scytus

How does this compare with the M-Stage Matrix? I haven't been able to find any in-depth comparison between the two.
   
  I was leaning toward the Matrix as I was looking for a more warm/bass-friendly amp, giving full body/volume bass presence, and unsure if the Lovely cube provides similar traits.
   
  http://www.head-fi.org/forum/thread/501046/first-impressions-lovely-cube-semi-diy-amp-lehmann-black-cube-linear-clone/105#post_6964362
  ^That review didn't really explain too well..
   
  They're both based off the BCL, so they can't be that different from one another?


----------



## BlaBlaBla

Quote: 





scytus said:


> How does this compare with the M-Stage Matrix? I haven't been able to find any in-depth comparison between the two.
> 
> I was leaning toward the Matrix as I was looking for a more warm/bass-friendly amp, giving full body/volume bass presence, and unsure if the Lovely cube provides similar traits.
> 
> ...


 
   
  They are different because of internal parts. If you change capacitors and resistors it will sound different. If you change opamp it will sound different. If you use different soldering iron it will sound different. If you use different cable it will sound different.


----------



## BlaBlaBla

Quote: 





t.iizuka said:


> The initial product that seems to have been reversed.
> Recent finished product there is no problem. (confirmed with my friend to buy)
> 
> I just use it without processing.
> If I knew then that the opposite problem.


 

 I have had the same problem. But when I changed digital source from Audiotrak Prodigy to M-Audio Revolution, that problem is gone.
  Because M-Audio twists left and right channel.


----------



## T.IIZUKA

Quote: 





blablabla said:


> I have had the same problem. But when I changed digital source from Audiotrak Prodigy to M-Audio Revolution, that problem is gone.
> Because M-Audio twists left and right channel.


 

 On the other hand can simply insert the cable?


----------



## JiggaD369

Can something like this help the LC?
   
http://circulator.bravehost.com/Gminireg.htm


----------



## Scytus

blablabla said:


> They are different because of internal parts. If you change capacitors and resistors it will sound different. If you change opamp it will sound different. If you use different soldering iron it will sound different. If you use different cable it will sound different.




Oh I see,

These DIY's are awesome, feel more personalized. Is it possible to modify it to add more low end to the amp, without sacrificing soundstage? And if so how would you do it, replace the opamp?


----------



## BlaBlaBla

Quote: 





scytus said:


> Quote:
> 
> 
> 
> ...


 

 That is just what I wanted to say.
   
  OPAMP is probably the best solution. But you have to find right OPAMP that will give you exactly what you want. Try to search over internet. Some people say that OPA2111 is good choice. As it depends on rest of setup, in every setup "the best choice" will be different. I mean, something what suits good to me, does not necessary mean that it will be good for you.
   
  The final result mostly depends on your headphones.
   
  What headphones do you have?


----------



## JiggaD369

Hey guys,
   
  Please let me know if anyone needs any PCBs as I plan to order them this week. I can also order parts for the LC if you need them.


----------



## Scytus

Quote: 





blablabla said:


> That is just what I wanted to say.
> 
> OPAMP is probably the best solution. But you have to find right OPAMP that will give you exactly what you want. Try to search over internet. Some people say that OPA2111 is good choice. As it depends on rest of setup, in every setup "the best choice" will be different. I mean, something what suits good to me, does not necessary mean that it will be good for you.
> 
> ...


 


  Still deciding on that as well, was leaning toward the Pro900s?


----------



## francisdemarte

jiggad369 said:


> Hey guys,
> 
> Please let me know if anyone needs any PCBs as I plan to order them this week. I can also order parts for the LC if you need them.




How much is a board?


----------



## Comfortable

Sorry for interupting, but is Lovely Cube worth the $250 or would money be better spent on Meier Concerto? How does LC compare to others?


----------



## BlaBlaBla

Quote: 





comfortable said:


> Sorry for interupting, but is Lovely Cube worth the $250 or would money be better spent on Meier Concerto? How does LC compare to others?


 


 Are you trying to compare amplifier that costs 800 USD (Meyer Corda) with amplifier that costs 250 USD (Lovely Cube)?
   
  Lovely Cube is not worth the 250 USD, in the same way as the Meyer Corda is not worth 800 USD.


----------



## BlaBlaBla

Quote: 





scytus said:


> Still deciding on that as well, was leaning toward the Pro900s?


 

 Ultrasone Pro 900? I think you should have enough bass...
   
=933&graphID[]=2661&graphID[]=373]http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=933&graphID[]=2661&graphID[]=373
   
  My brother has AD700 and there is enough bass. But sometimes I feel that highs are not good enough. On AD900, highs and lows are even better than on AD700. But still I have to level up 4kHz - 10kHz range. My opinion is that, the best amplifier is the one on which you do not have to mess with your equalizer (leave flat characteristic). Every other amplifier that needs help from equalizer is "not good enough". And can be better.
   
  Grado SR225 has something. Entire range is excellent. I do not need to use equalizer. Everething is like it should be. Only drawback is that sound stage is smaller compared to ATH...But I have not known what is the real meaning of a term "listening to music" until I bought Grado. My wish is to have Grado RS2i. 
	

	
	
		
		

		
			




   
  On Sennheiser HD415 there is too much bass. On Sennheiser HD485 there is enough bass for entire neighborhood. There is no reason to use equalizer, because sound that comes from bad headphones, can not be improved.


----------



## Comfortable

double post


----------



## Comfortable

It IS a DIY amp, I expect on par with $500 amps or greater, I know Corda will sound better, for sure. Is it worth the feeling of "upgraditus" or buy Meier's and be done with it? What can LC be evenly compared to?


----------



## Knusperfisch

Why don't you just read some reviews of the M-stage ? LC and M-Stage should be comparable even though the LC should be slightly better.
  All that I can say so far that the amp sound quality is good and improved within the burn-in time. But I don't want to say too much for now since I've listened to it for 50 hours now. The break in is done within 100 hours. (according to Stephen) I'm really curious about if there will be a further improvement.
  Don't bother, your money will be well spend^^


----------



## BlaBlaBla

http://imageupload.org/?di=412991004552


----------



## JiggaD369

Bla, do you think the gain switches underneath the board are required if a permanent opamp is used (Burson in my case)?


----------



## sunneebear

If all your headphones ae of the same impedance then you can set and forget.  Also if you only have one headphone... but this is head-fi.


----------



## JiggaD369

Well I'm pretty set on my 600ohm Sextetts. 
	

	
	
		
		

		
			




   
  But how would I determine what I have to substitute in place of the switches?


----------



## gwikse

Seems pretty straight forward to play around with the power supply. By not mounting the regulators the output at the rear can be used as an input.
  The pot can be bypassed if used with an external passive pre-amp or variable output dac. Hmmm lots to play with


----------



## sunneebear

Quote: 





jiggad369 said:


> Well I'm pretty set on my 600ohm Sextetts.
> 
> 
> 
> ...


 


  Nothing.  The switches just select some resistors on the board.  I believe the two sets on both sides of the opamps.  If you want to take the switches out of the signal path just find the value setting that sounds best with your AKGs and hardwire it in.


----------



## gwikse

The simple discrete op-amp mod. Just tilt the caps.


----------



## francisdemarte

gwikse said:


> Seems pretty straight forward to play around with the power supply. By not mounting the regulators the output at the rear can be used as an input.
> The pot can be bypassed if used with an external passive pre-amp or variable output dac. Hmmm lots to play with




Replace the 4 switches with 2 switches mounted in the case! I don't see a need at any time to set two different gains for L+R


----------



## JiggaD369

Quote: 





sunneebear said:


> Nothing.  The switches just select some resistors on the board.  I believe the two sets on both sides of the opamps.  If you want to take the switches out of the signal path just find the value setting that sounds best with your AKGs and hardwire it in.


 

 BY value, do you mean resistance?


----------



## sunneebear

Yes.


----------



## JiggaD369

Now a stupid question: how to I find out the right resistance?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Now a stupid question: how to I find out the right resistance?


 
   
  In Lovely Cube you have four choices (from low gain to high). First is both switches off (gain 1), second is 2.2k on, third is 680R on, fourth is two resistors in parallel connection - that means 520R.
   
  You should try two resistors - 680R and 520R.


----------



## ringer

Is it OK to use opamp 2111 with class A bias mod? It sounds good, but I worry about heating. I don't have thermometer, but I think it rises up to 50-55 degree Celsius when the case is closed. And there is winter today, what will be on summer...


----------



## francisdemarte

blablabla said:


> In Lovely Cube you have four choices (from low gain to high). First is both switches off (gain 1), second is 2.2k on, third is 680R on, fourth is two resistors in parallel connection - that means 520R.
> 
> You should try two resistors - 680R and 520R.





Pick up one of these cheap solderless breadboards and try different resistor values:

http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_primer-simplecircuit.shtml


----------



## BlaBlaBla

Quote: 





ringer said:


> Is it OK to use opamp 2111 with class A bias mod? It sounds good, but I worry about heating. I don't have thermometer, but I think it rises up to 50-55 degree Celsius when the case is closed. And there is winter today, what will be on summer...


 


  On summer, it will be like hell. You should make another amp, just for back up... 
   
  I just can't swallow that statement "has to be warm to have good sound". I am trying, but I can't... 
   
  When it is cold it has bright signature. When it is hot, it has warmer signature... But it DOES NOT SOUND BETTER. 
   
   
  Has anyone tried to remove ALPS in a Lovely Cube and put there resistor or wire? I have Matrix Mini I and I can change volume on its RCA output when it is in power mode (headphone out is on)... I was thinking to remove ALPS in Lovely Cube and use it as a pure amplifier (without pot)...


----------



## ringer

Quote: 





blablabla said:


> On summer, it will be like hell. You should make another amp, just for back up...
> 
> I just can't swallow that statement "has to be warm to have good sound". I am trying, but I can't...
> 
> ...


 

 I was thinking about DACT. But the price bites. Besides, I don't know if it really change sound quality significantly or not.


----------



## BlaBlaBla

Quote: 





ringer said:


> I was thinking about DACT. But the price bites. Besides, I don't know if it really change sound quality significantly or not.


 

 $165 plus shipping costs... 
	

	
	
		
		

		
			




   
http://www.diycable.com/main/product_info.php?cPath=35_145&products_id=635
   
  They have cheap polyprophylene capacitors...


----------



## sunneebear

I removed two ALPS to gear them in together so I could run two LC amps as balance.


----------



## ringer

I have tested 2134, 2111 and 627 opamps on RMAA program. The winner is 2111 with class A bias mod pack 4.3K resistors.


----------



## ringer

This is how my LC looks like now.
   

   
  For opamp power supply I've used Elna Cerafine 100uF + 1000uF. 100uF for very fast charging/discharging cycles that has to improve micro dynamic. 1000uF for better noise filtration, macro dynamic and bass control. Don't know if it really works the way I think, cause I don't know radio engineering science 
	

	
	
		
		

		
		
	


	



   
  1.5uF and 22nF in signal part I've simply throw away.
   
  It sounds better now. Very clean and deep.


----------



## BlaBlaBla

Quote: 





ringer said:


> I have tested 2134, 2111 and 627 opamps on RMAA program. The winner is 2111 with class A bias mod pack 4.3K resistors.


 

 Unfortunately RMAA does not tell you all.
  My old M-Audio Revolution has better S/N ratio than Matrix Mini I. But when I listen to music and compare M-Audio DAC vs Matrix DAC, Matrix Mini I kicks M-Audio butt. The same goes with amplifier in Matrix Mini I and M-Audio.
   
  I do not believe in RMAA because it will not tell you the whole story. RMAA can't tell you how wide and deep will be sound stage, it can't tell you in which way sound card handles with sound. If it has warm or cold signature... Especially it can't tell you how sound will be when you connect headphones to your amplifier. Sound is not made only by numbers.


----------



## BlaBlaBla

Quote: 





ringer said:


> This is how my LC looks like now.
> 
> 
> 
> ...


 
   
  I am glad that you are satisfied! 
   
  I were you, I would not remove input capacitors... If you get DC signal on input, you can call your headphone supplier for another pair.


----------



## ringer

Quote: 





blablabla said:


> Unfortunately RMAA does not tell you all.
> My old M-Audio Revolution has better S/N ratio than Matrix Mini I. But when I listen to music and compare M-Audio DAC vs Matrix DAC, Matrix Mini I kicks M-Audio butt. The same goes with amplifier in Matrix Mini I and M-Audio.
> 
> I do not believe in RMAA because it will not tell you the whole story. RMAA can't tell you how wide and deep will be sound stage, it can't tell you in which way sound card handles with sound. If it has warm or cold signature... Especially it can't tell you how sound will be when you connect headphones to your amplifier. Sound is not made only by numbers.


 

 I agree with you. But I felt that 2111 in class A sounded better that is why I decided to make measurements. And according to RMAA my feelings were right.


----------



## ringer

Quote: 





blablabla said:


> I am glad that you are satisfied!
> 
> I were you, I would not remove input capacitors... If you get DC signal on input, you can call your headphone supplier for another pair.


 

 Yes, and now I can't use my amp with any music source. Before plugging headphones I have checked DC on input and output of Lovely Cube.


----------



## ringer

If I find very good 1.5uF caps which fit in LC case I will use them for sure.


----------



## gwikse

I have put together most of the first LC. I regret that I ordered kits as I desided that I need to listen intensively on the cube before making alterations.
   
  I can not see much at the moment either so I must say that I am very nervous and will keep my distanse away from the amp on first startup... (expecting it to blow up in my face otherwise...).
   
  The model has been useful and the op-amp was easy to fit with tilted caps.
   

   
  If the amp lives up to my expectations with no or only small alterations then the project will be taken to the next level (original philips trans, BG caps, better resistors and a custom chassis wich I currently am working on in 3d.
   
  More to come. Now I must get some sleep so that I can finish the stock amps to get an impression.


----------



## gwikse

Quote: 





francisdemarte said:


> Quote:
> 
> 
> 
> ...


 


   


  Quote: 





blablabla said:


> On summer, it will be like hell. You should make another amp, just for back up...
> 
> I just can't swallow that statement "has to be warm to have good sound". I am trying, but I can't...
> 
> ...


 

 I also have a Matrix Mini-i and this would be the way I would do it if it had not been for the fact that I need analog inputs as well as digital.


----------



## francisdemarte

I am also going to remove the Alps pot and use the digital volume control from my DAC. Can someone give me some instructions on which pins to jumper?



Do I just jumper input1 and wiper1 then input2 and wiper2?


----------



## VictoriaGuy

Quote: 





francisdemarte said:


> I am also going to remove the Alps pot and use the digital volume control from my DAC. Can someone give me some instructions on which pins to jumper?
> 
> 
> 
> Do I just jumper input1 and wiper1 then input2 and wiper2?


 
  No need to remove the pot - just get some fine (solid core preferred) wire and jumper .......
  If you remove the pot, you should put 50k resistors between input and ground.
   
  Do you think you will hear a difference between jumpered and just 'pot wide open'.....??
  I don't see the point....


----------



## gwikse

Edit: Added resistors as VictoriaGuy suggested.


----------



## francisdemarte

A picture speaks a 1000 words! Thanks VictoriaGuy and gwikse!

I want to remove the pot so I can get more clearance in my new case.


----------



## ringer

I don't think digital volume control is the better solution than using ALPS. Lower signal comes in amp - worse signal/noise ratio you get. Stapped attenuators will be much better. Stephen selling some on the eBay page.


----------



## VictoriaGuy

Quote: 





ringer said:


> I don't think digital volume control is the better solution than using ALPS. Lower signal comes in amp - worse signal/noise ratio you get. Stapped attenuators will be much better. Stephen selling some on the eBay page.


 
  Stepped attenuators can be tricky to use if you have easy-to-drive /efficient headphones. If 'maximum' is 10 o'clock, there aren't a lot of steps to use. So make sure you get plenty of steps in your attenuator.......
   
  In an amp with the volume control at the input, I don't see how the s/n ratio will be affected by using source volume control, unless you have long and noisy interconnects.


----------



## ringer

Try to remove capacitors in signal part instead of removing ALPS. It gives you more benefits. But before plug headphones check DC on input and output, it must be less than 10mV. If you remove that caps and your DAC for some reasons has direct current on output it will be amplified and headphones will be died. So after this mod you have to connect LC only to trusted source of signal.
   
  Hope I have not make many mistakes and you understand me


----------



## ringer

Quote: 





victoriaguy said:


> In an amp with the volume control at the input, I don't see how the s/n ratio will be affected by using source volume control, unless you have long and noisy interconnects.


 
   
  If I set 100% volume on LC I can hear noise.


----------



## gwikse

Quote: 





ringer said:


> If I set 100% volume on LC I can hear noise.


 


  Have you tested without the pot. I would think that the pot itself is a large reciever of noice. Should be a lot less without it.


----------



## Scytus

I know that this is first and foremost a DIY thread, but I was considering buying the "Premium" Lovely Cube..
   
  and was hoping someone knows of how this compares to the Matrix M-stage? From what I've been reading, the M-stage has the exact sound signature I'm looking for, and can even be modified to class A biasing (as shown here: http://www.headfonia.com/matrix-m-stage-class-a-biasing/)
   
  I just wanted to know how their sound characteristics are similar/different. The actual Black Cube Linear was described to me as more on the analytical side, and less energetic, and was told it's not what I'm looking for.


----------



## gwikse

Quote: 





scytus said:


> I know that this is first and foremost a DIY thread, but I was considering buying the "Premium" Lovely Cube..
> 
> and was hoping someone knows of how this compares to the Matrix M-stage? From what I've been reading, the M-stage has the exact sound signature I'm looking for, and can even be modified to class A biasing (as shown here: http://www.headfonia.com/matrix-m-stage-class-a-biasing/)
> 
> I just wanted to know how their sound characteristics are similar/different. The actual Black Cube Linear was described to me as more on the analytical side, and less energetic, and was told it's not what I'm looking for.


 

 Not sure how they compare. Lovely cube can also be "modified" (the modification is done to the op-amp) into class A. lasercollection offers a kit at his page.


----------



## francisdemarte

scytus said:


> I know that this is first and foremost a DIY thread, but I was considering buying the "Premium" Lovely Cube..
> 
> and was hoping someone knows of how this compares to the Matrix M-stage? From what I've been reading, the M-stage has the exact sound signature I'm looking for, and can even be modified to class A biasing (as shown here: http://www.headfonia.com/matrix-m-stage-class-a-biasing/)
> 
> I just wanted to know how their sound characteristics are similar/different. The actual Black Cube Linear was described to me as more on the analytical side, and less energetic, and was told it's not what I'm looking for.




Someone owned both and compared the two a few pages back in this thread. They preferred the LC and ended up keeping it. From my perspective they are both nearly the same price and very close (if not identical) performance wise. My experience with both Tam (Coolfungadget) who sells the M-Stage and Stephen who sells the LC have both been favorable. 

The only difference I see is that the LC is more DIY modding friendly, and by modding I mean with a soldering iron. If you'd like to mod and tinker with your amps then I'd definitely go with a LC, if you have no plans beyond op amp rolling then you okay with either amp.


----------



## ringer

Guys, what do you think about adding 2x10000uF in output of power supply?
   
  http://www.alicemagicbox.com/lasercollection/lovelycube/lovelycubecircuit02a.jpg


----------



## Scytus

Quote: 





francisdemarte said:


> Quote:
> 
> 
> 
> ...


 

 I've been reading though that the Lovely Cube is almost a direct duplication of the black cube linear, while the M-stage is a slightly altered version. Someone also told me that the Black Cube wouldn't fit my tastes..while everything I've read of the M-Stage fits wonderfully, hence my fear (as I somewhat prefer the look, and price of the Lovely Cube).
   
  I came up with a better idea, a good way to find out is to ask you Lovely Cube owners if it has the qualities I'm looking for. Does it have a warm signature, prominent low end and incorporates a wide soundstage?


----------



## francisdemarte

My LC is pretty warm with the OPA627 op amp has excellent low end (as well as highs) and wide sound stage. For a warmer presentation I think most people in the thread lean toward Burr Brown op amps. 

If you want really lush mids and warm presentation I'd suggest looking into tube or tube hybrid amps. No matter what what op amp I try the LC is no way as warm and lush as my tube hybrid EF-5. It sound great with jazz and vocals. It gives up some speed and a bit of the high end over the LC but I don't miss it.

Get one used and if you don't like it re-sell it. It's very hard to describe sound you've never heard before.

I also found out recently that a quality source makes a high difference too. Bought a fellow members Dual Mono Opus DAC and the sound stage is HUGE compared to any sub $300 DAC and sound card I've owned.


----------



## Scytus

Quote: 





francisdemarte said:


> My LC is pretty warm with the OPA627 op amp has excellent low end (as well as highs) and wide sound stage. For a warmer presentation I think most people in the thread lean toward Burr Brown op amps.
> 
> If you want really lush mids and warm presentation I'd suggest looking into tube or tube hybrid amps. *No matter what what op amp I try the LC is no way as warm and lush as my tube hybrid EF-5*. It sound great with jazz and vocals. It gives up some speed and a bit of the high end over the LC but I don't miss it.
> 
> ...


 
   
  I was told that tube amps don't work well with Ultrasones (what I have) or Denons, and that you should use SS amps instead. Shouldn't tube amps be used rather with Sennheisers/Audio-Technica's?


----------



## gwikse

I would try a tube buffer between the source and an LC or M-stage if you want more warmth.
   
  I`d rather "mold" the sound at the source.


----------



## TheKisho

Quote: 





gwikse said:


> I would try a tube buffer between the source and an LC or M-stage if you want more warmth.


 

 Do you have one in mind?  Tubes aren't always warm (it's circuit for the most part that makes them warm).
   
   
*@Scytus *Maybe they just mean it doesn't work with other people's tastes.  Just because someone here says it doesn't work doesn't mean it won't work for you and you wouldn't enjoy it.  Try a hybrid, if you don't enjoy the sound you could always sell it.


----------



## gwikse

Oops I was a bit quick with that reply.
   
  I (would) use the following.
   
  Source (computer, cd player, turntable, ipod....)
  DAC (when needed)
   
  1. Into LC or M-stage via a input selector
  2. Into a tube buffer and then into LC or M-stage via input selector
   
  Headphones.
   
  Why?
   
  Well I like to have the flexability and "moodability".
   
  I would not run a pure valve amp and I will not get rid of my tube buffer (M.F. clone).


----------



## francisdemarte

Here's is my tube buffer, currently in use on my speaker setup.

Yaqin SD-CD3 with NOS RCA 6F8G tubes on an adapter. $160USD shipped from ebay.





This is how it looks with the stock tubes and tube guard.



Gives the sound a nice boost in warmth and soundstage and a bit of gain.


----------



## gwikse

That looks very nice. Have you tried it with LC?
   
  Edit: spelling...


----------



## gwikse

Here (red arrow) is a possible reason for the heat issue.
   
  The washer needs to be flush or lower than the regulator. Otherwise the thermal resistance between the regulator and the HS will be extremely high.


----------



## BlaBlaBla

Has anyone tried to use silver grease for CPU-s instead pads?
   
  Quote: 





gwikse said:


> Here (red arrow) is a possible reason for the heat issue.
> 
> The washer needs to be flush or lower than the regulator. Otherwise the thermal resistance between the regulator and the HS will be extremely high.


----------



## gwikse

I will proborably use Arctic Silver 5 or thermal pads, but I am not sure if it will work well on the stock faces. They may be a bit too rough. Lapping them will proborably help a lot, but the thermal difference will proborably not be worth the effort. Thermal pads are typically better with rough faces.
   
  My initial impression of this amp are good. So next step is to integrate it into my main rig. I will use "high-end" caps, resistors and other parts. The regulators may also be replaced by some sort of "super regulator".
  The idea was originally to make a chassis to be mounted at the rear of my computer screen, but I want to make use of it in my speaker setup as well. Due to the pre-out mute function on one of the headphone outputs this will be easy. The cables to my headphones will have to be long though. I am thinking about making a fixed cable run with connectors at the two places I use headphones; in front of my computer screen and next to my evening chair. The attenuator has a remote system (that large lump at the rear of the attenuator is a motor, and the print at the upper left corner is a controller for the motor).
   
  This is how it will be inside the chassis (aluminium 3mm bottom plate, 8mm front, rear and side and 5mm top plate). The regulators are mounted directly to the bottom plate wich will make the entire chassis an hs.
  Holes will be drilled in the front of the bottom plate and at the rear of the top.
   
  So now I just have to deside on wich parts to use. This is what I am thinking atm.
   
  Shinkoh Tantalum resistors in signal path, Allen bradley Carbon in power supply path. The power resistors will be 1W instead of 0,5W

 Nichicon Muse KZ elec, Russian PIO K40Y paper in oil  and Mundorf Supreme at the input (signal path).
   
  Anyways. Here is a picture.


----------



## gwikse

Audeze LCD-2 are the cans to be driven.    
First impressions of replacing the alps with dact are better soundstage and what seems like a more controlled and relaxed soundstage. This amp has great potential. It sounds great right out of the box but there are a lot of possible upgrades that will bring it past most amps I`ve heard. I hope I get the caps soon so that the testing can begin. The Nichicon Muse KZ are a "cheap" option but from what I`ve heard they might be a killer in this amp. Input caps will have to be something more extreme though. Jensen Alu 1,5uF + Jensen AG 0,0015uF may be the way to go. They are the closest to a wire I`ve heard so far.
   
  Since I am also going to use "super-regulators" the 470uF`s may be replaced with smaller film types as well. The noice from the regulators are much less than with 317/337`s.
   
  The regulators I`m going to use:
   
  http://www.teddypardo.com/DIY/SuperTeddyReg.html


----------



## BlaBlaBla

This is what I need...
   
http://tech.juaneda.com/en/articles/lm317.html
  
  Last time, FM capacitors ****ed up everything and I thought that I did something wrong with transistors. Pulled out all transistors and messed up the board. To hell with Panasonic FM and their low impedance... I had luck because PRP resistors and other stuff is tough built, so only PCB was wasted. Now I think to drive headphones without capacitors. Only small 22nF-100nF on out. Too much crap is just too much. I have to find a value that is enough for circuit to be stable.
   
   
  Quote: 





gwikse said:


> Audeze LCD-2 are the cans to be driven.
> First impressions of replacing the alps with dact are better soundstage and what seems like a more controlled and relaxed soundstage. This amp has great potential. It sounds great right out of the box but there are a lot of possible upgrades that will bring it past most amps I`ve heard. I hope I get the caps soon so that the testing can begin. The Nichicon Muse KZ are a "cheap" option but from what I`ve heard they might be a killer in this amp. Input caps will have to be something more extreme though. Jensen Alu 1,5uF + Jensen AG 0,0015uF may be the way to go. They are the closest to a wire I`ve heard so far.
> 
> Since I am also going to use "super-regulators" the 470uF`s may be replaced with smaller film types as well. The noice from the regulators are much less than with 317/337`s.
> ...


----------



## gwikse

These may also work well.
   
  http://paulhynesdesign.com/page6.html


----------



## ringer

I've added a few output capacitors. 8 pieces 1000uF each.


----------



## JiggaD369

Quote: 





gwikse said:


> These may also work well.
> 
> http://paulhynesdesign.com/page6.html


 


  Are these regulators just plug in replacements for the LM3xx? Or do you have a add/subtract parts from rest of the board?


----------



## ringer

Quote: 





jiggad369 said:


> Are these regulators just plug in replacements for the LM3xx? Or do you have a add/subtract parts from rest of the board?


 
  I think this is for direct replacement.


----------



## JiggaD369

What about using something like this?
   
http://circulator.bravehost.com/Gminireg.htm


----------



## gwikse

Quote: 





jiggad369 said:


> Are these regulators just plug in replacements for the LM3xx? Or do you have a add/subtract parts from rest of the board?


 


  I am not sure. At first I thought these were drop in replacements but now I see that they are spesified for different voltages.
   
   
  Quote: Paul Hynes


> ......[size=x-small]Contact for applications advice......[/size]


----------



## Heidegger

Quote: 





scytus said:


> I've been reading though that the Lovely Cube is almost a direct duplication of the black cube linear, while the M-stage is a slightly altered version. Someone also told me that the Black Cube wouldn't fit my tastes... Does it have a warm signature, prominent low end and incorporates a wide soundstage?


 

 The authentic BCL's sound signtature is not on the warm, tubey side. I was looking for an amp to dissipate the "dark veil" that I heard on my Sennheiser HD650. The BCL did just that. My formerly dark-sounding 650 now sounds bright and clear. At first, the BCL sounded too bright, and the highs seemed to be a little grainy and to crowd out the mids a little bit. Either I got used to it or the amp really needed a few months to break in because it no longer sounds too bright, and I don't hear the grain. The clarity of this amp astounds me. Also, the first few days the amp sounded a slow and hazy (sluggish), but again: that was then; this is now. I never believed in break-in until I purchased this amp.
   
  Compared to my last amp (a $350 HeadRoom Micro Amp), the BCL didn't add much by way of horizontal soundstage, but it did add _depth_. The headroom isn't much wider, but yes it's more three dimensional. The vertical space also seems to have grown. All the instruments sound larger and fuller than they did before. I will say that with the 650 I sometimes felt like I was sitting a few rows back; the music seemed to be out there somewhere. The phones sounded a little unengaging. But with the BCL, the sound is immediate and enveloping. I often hear instruments and voices not only right inside of me with this amp-headphone combo, but _behind_ and all around. Still, I would have liked the soundstage to be a little wider particularly with orchestral music. That's my only beef with it, but it might be the fault of the headphone rather than the amp.
   
  As for the bass, I definitely _feel_ it more than I did with the HeadRoom amp, but only when the BCL-650 combo is called upon to provide it. In general, the sound is neutral to slightly on the bright side rather than warm, dark, or boomy. What has impressed me most of all about the BCL is how textured it makes my 650 sound. With a lot of music, I can literally feel the air pressure change around my ears. I do not exagerate when I say that my ears and brain often feel tickled and massaged. It's a real physical delight.
   
  Music with a lot of percussion and drumming impresses me most of all with this amp. Wow! This is because the BCL drives my 650 with lots of speed. The BCL can be very forceful, even aggressive. My headphones used to sound a little slow and polite. Not any more. Instead of warm, if anything sometimes the music sounds _red hot_ -- that is, juiced up with lots of energy. If I turn the BCL off while the music is still playing, it literally takes a second or two _after I flip the switch_ for the music to stop. This amp is _pumped _and ready for action. But I don't think I could recommend the BCL in your case because generally the sound isn't warm. It's bright, even if very energetic. 
   
  I find that reports that the BCL gets too hot are totally exagerated. The amp gets pleasantly warm, and it doesn't affect the ALPS pot.
   
  Anyhow, this thread is a virtual workshop. Fascinating. In fact, it was this thread that convinced me to buy the BCL. After reading you guys a few months ago, I decided that I'm not a DIYer, so I shelled out the bucks for the real deal. Not that the LC is "less real" than the BCL; it's just that it seems to me that the standard lovely cube -- and correct me if I'm wrong -- is _not _comparable to the BCL. In order to get it up to the quality of the BCL, it seems to take a lot of changes and modifications, which I was not willing to do myself.


----------



## khatch

Quote:


heidegger said:


> After reading you guys a few months ago, I decided that I'm not a DIYer, so I shelled out the bucks for the real deal. Not that the LC is "less real" than the BCL; it's just that it seems to me that the standard lovely cube -- and correct me if I'm wrong -- is _not _comparable to the BCL. In order to get it up to the quality of the BCL, it seems to take a lot of changes and modifications, which I was not willing to do myself.


 

 I really couldn't agree more.  X2


----------



## tyoung8

Quote: 





khatch said:


> Quote:
> 
> I really couldn't agree more.  X2


 

 You don't have to be a DIYer to buy the Lovely Cube.  Can also be bought assembled.
   
  Lovely Cube Premium
http://www.alicemagicbox.com/lasercollection/lovelycubepremium.html


----------



## BlaBlaBla

If someone has a lot of money, he can spend it on BCL or whatever he wants... 
  I do not have a lot of money and usual use common sense... My common sense tells me that BCL is not worth $1000. Also I think that it goes too warm (and LC also). I do not care about temperature measured on metal box. I care about temperature measured on BD transistors. There temperature goes above 80°C. And that is too much if I want to use amplifier for more than one year. I know the first rule of every maker or seller: "It must work until new version comes out."  All are the same.
   
  A class does not means "high temperature". It means "better sound" if it is implemented in a good way. $200 amplifier, that has transistors "on fire" - is just OK. But for something over 1K, I expect better A class implementation *(cooling)* and not just "a brand" or "the name".
   
  30 years ago, all electric equipment was working for 10-15 years. I have 15 years old Sony TV. And it works flawlessly. I have old Zeiss and Takumar lenses that have over 20 years. They do not have auto focus ability, but they are built like a tank, and work flawlessly. Even Zeiss Jena lenses are optically better than 90% plastic lenses that people today usually get in a "kit" package. They can be repaired because they are made of simple METAL parts. Today, you are able to buy 18 mpix camera but lenses that you get with that camera are not capable to fill up 8 mpix sensor. So,every time when something new comes out, you have to buy new lenses, because those old one where for old cameras... Just another trick.
   
  All things made in last 10 years *aren't worth crap*. Because technology improves too fast, and nobody wants to make something that will last more than 2-3 years. The more you sell - the more you will have to produce. You will not sell too much, if you make products that are able to work 20 years without hitch.


----------



## Majestyk

BlaBlaBla:  I totally agree!  When I buy a headphone amp, I want it to last for years and still be working for years more, when I sell it to the next owner.  If 80 degrees is correct, than well, it's not going to have a long life.  I don't know why I'm not seeing vents or fans on many headphone amps or at least an optional cover with ventilation.  Even when I buy TV's, I always check the back of the demo sets, to see how hot/cool they are running.
   
  Does anyone know if the Lovely Cube Premium runs just as hot?  Also, sound wise, how similar is it to the BCL and what is the warranty?  I'm trying to decide whether to buy this or the M-Stage.


----------



## tyoung8

This is what the seller says about heat issue:
   
http://www.alicemagicbox.com/lasercollection/lovelycubesecretofheat.html
   
  I am not sure why the Lovely Cube don't get as much hype as the Matrix M-Stage when it is suppose to be more similar than the BCL.  I think it might be that at one stage you can only get it for DIY and not fully assembled.


----------



## francisdemarte

A headphone amplifier is a very simple device. Outside of the volume pot and switches there are no moving parts to wear out, unlike speaker amplifiers or tube amplifiers they do have to deal with high voltages. 

Even with power amplifiers, my 1979 made Marantz receiver is still going strong to this day on it's original components. The only type of maintenance I had to do was clean some scratchy pots, replace some lightbulbs, and do a very minor adjustments to the amplifier bias.

Even running at over 80C, which for solid state components really isn't that hot, I suspect the amplifier will out live most of us. I suspect in this hobby we'll move on to the next big thing way sooner than reaching component failure.

For the paranoid it helps if can move your LC into a larger case. Keep in mind that if your case is warm, that just means it's doing it's job and sinking interior heat to the outside air. Relax.



tyoung8 said:


> I am not sure why the Lovely Cube don't get as much hype as the Matrix M-Stage when it is suppose to be more similar than the BCL.  I think it might be that at one stage you can only get it for DIY and not fully assembled.




That's correct up until recently the LC wasn't offered as a completed amp. When I first started the thread you can get it as a populated board, just the PCB, or all the case parts separately. When you added up all the parts and shipping it cost about the same as a M-Stage and you had to put it together yourself. This is more a DIY'ers amp. 

The cool thing is there a few exoticly modded LC's out there, even a couple of balanced ones. The most I've seen done with the M-Stage are some component swaps.


----------



## tyoung8

I think you should change the title of the thread from 
   
   
 First Impressions: Lovely Cube semi-DIY Amp (Lehmann Black Cube Linear Clone)   
  To 
   
   
 Lovely Cube Premium (Lehmann Black Cube Linear Clone and better than the Matrix M Stage!!!)   




   
  Hopefully, it can than get more hyped and I can read more peoples impression of the Lovely Cube.


----------



## Majestyk

I was reading on another forum that the Sennheiser HD800's don't sound very good with the M-Stage but do with the Black Cube.  I'm wondering if anyone is using these headphones with the Lovely Cube and if it's handling them well.  If so, I think it could be a good testament to how similar the LC and BCL are.
   
  Link:
   
http://www.headfonia.com/lehmann-black-cube-linear/
   
  (With comments below)


----------



## francisdemarte

Thread Title updated! I think we're way past First Impressions


----------



## francisdemarte

majestyk said:


> I was reading on another forum that the Sennheiser HD800's don't sound very good with the M-Stage but do with the Black Cube.  I'm wondering if anyone is using these headphones with the Lovely Cube and if it's handling them well.  If so, I think it could be a good testament to how similar the LC and BCL are.
> 
> Link:
> 
> ...




Only review with an HD800 for the Lovely Cube was from Stau

http://www.head-fi.org/forum/thread/501046/the-lovely-cube-semi-diy-headphone-amp-lehmann-black-cube-linear-clone/105#post_6964362


----------



## tyoung8

I think it is the 'Semi DIY' bit that needs to be taken out.


----------



## Majestyk

Can anyone recommend me a good pair of closed headphones, under $300, for this the LC?


----------



## francisdemarte

Majestyk

What headphones do you currently own? You should really figure out what headphone you like then build the rest of the system around them.


----------



## Majestyk

Well I didn't mean to turn this in to a 'help Majestyk find headphones' thread. But since you asked...And hey it is dead here lately.  
	

	
	
		
		

		
		
	


	




  I currently have the Sony MDR-7506 headphones.  They are definitely not perfect but they have served me well over the years.  I'm only interested in closed headphones since my place is rather noisy with construction outside.  I've thought about the Shure SRH840's and maybe the AKG K240MKII's, which I believe are not fully closed headphones but I think they would be good enough for noise cancelling.


----------



## Mad Max

HD25 has the most noise cancellation right before _active_ noise-canceling headphones.  K240 is listed as semi-open.
  There's also HFI580/680/780 and PRO-550 around that price, I don't know how good their isolation is.


----------



## panda-R

does this pair well with the DT880 / 600 ohms? I figure if it can power the HD650/HD800 it should be pretty good for the beyers too.


----------



## BlaBlaBla

Hm... I do not know about headphones for LC. I am happy owner of Grado and ATH. They both have strengths and weaknesses. Mostly it depends on type of music that listener wants (or likes) to listen to. I figured out that ATH is excellent for movies and games (I do not play PC games but like to watch movies...). Grado, on the other hand is excellent with guitar and drums and puts magic warmth in music (especially female vocals). I think that high impedance one, have to be avoided. SS amplifiers are good where a lot of current is needed. Tube amps are (generally) better for big voltage swing. Some people say that hybrid amps (tube with SS on output) are the best. Because they have preamplifier that has voltage swing "borrowed" from tube amps and output current "borrowed" from SS amps...
   
  Lots of people have habit to spend 1000 USD on headphones in a hope that sound will be better if the price of headphones is higher... But it does not go in that way. It is like buying a Porsche 911 (because it is expensive and sports car) and driving it through overcrowded city. In the same way, good headphones need good amplifier. The best one need the best amplifier. I tried a few low cost amps with DAC (below 500 USD) and I have feeling that, in that price range, everything over 200-300 USD for headphones, is just like "throwing money through window". Even worse, high class headphones will reveal every flaw of amplifier (and entire setup), but low cost one - will not. In that case, you will listen more to the music as it is, and less thinking about flaws.
   
  Also, there are two approaches. First is "music in the studio", and second is "music at home". In the studio, people need technically the best equipment, that will show every possible flaw - technical flaw. It is important for recording. But at home, people need something that will have "something more than pure technical data".


----------



## Mad Max

Quote: 





blablabla said:


> ...  Also, there are two approaches. First is "music in the studio", and second is "music at home". In the studio, people need technically the best equipment, that will show every possible flaw - technical flaw. It is important for recording. But at home, people need something that will have "something more than pure technical data".


 

 Indeed.  However, also consider that most of us don't have the trained ears of a good orchestra director/conductor or recording engineer and such.  So a high analytical ability is still okay, I think, for home listening as it makes music sound even more eye-popping when it is _relatively_ well-recorded.
  Of course we may or may not hear flaws but not quite to the extent of a trained pro.


----------



## DjAmTraX

I like the BCL so much I bought two. One in black and one in silver. I would love to do a side by side with the LC on HD800, but I'm not ready to throw away $300 yet. Maybe someone can send me on for review.


----------



## DjAmTraX

The LC:
   

   
  Lehmann BCL:


----------



## Majestyk

The first page of this thread needs a photo of the Lovely Cube Premium, to show newcomers that they can buy an assembled one.
   
  The photo on the alicemagicbox site is too small, however.


----------



## tyoung8

Quote: 





djamtrax said:


> The LC:
> 
> 
> 
> Lehmann BCL:


 

 oooo  The layout look exactly the same.


----------



## francisdemarte

majestyk said:


> The first page of this thread needs a photo of the Lovely Cube Premium, to show newcomers that they can buy an assembled one.
> 
> The photo on the alicemagicbox site is too small, however.




First Page updated!



djamtrax said:


> I like the BCL so much I bought two. One in black and one in silver. I would love to do a side by side with the LC on HD800, but I'm not ready to throw away $300 yet. Maybe someone can send me on for review.




You might want to try emailing Stephen and try to convince him to send you a review unit.


----------



## panda-R

the lovely cube is so inexpensive u should just buy it and try it out!


----------



## tyoung8

Quote: 





francisdemarte said:


> Quote:
> 
> 
> 
> ...


 

 Great stuff.  Hopefully, it'll get more attention now so I can read more reviews.  Especially LCP vs Matrix M Stage.  Most likely to get the LCP when I decide to buy a proper amp.


----------



## DjAmTraX

I sent an email request for a review sample. Hope to hear back soon. 

_I am a huge headphones guy and I love the sound of my Lehmann Audio Black Cube Linear. I like it so much I bought two. One in black for the bedroom and one in silver for the hi-Fi room.  I recently came across your site and I am very interested.  I do a lot of video unboxings and product impressions posted on Head-Fi.org and many other audio forums. I would love to have the opportunity to sample/review/compare the Lovey Cube. I will do an honest comparison of the LC against the Lehmann BCL and email you my findings prior to posting on the web. If I like the LC, I will buy it. If I don't, I will send it back. 
I can email you some of my write up samples and unboxing videos. Would you be interested in sending me a review sample? _


----------



## Majestyk

Just out of curiosity, would you guys prefer having the input switch and one headphone jack on the LC, like the M-Stage has?  I'm not sure what the point of having the two headphone jacks is...Aside from cloning the BCL.


----------



## DjAmTraX

majestyk said:


> Just out of curiosity, would you guys prefer having the input switch and one headphone jack on the LC, like the M-Stage has?  I'm not sure what the point of having the two headphone jacks is...Aside from cloning the BCL.



I much prefer two inputs over two headphones out.


----------



## panda-R

my lovely cube just arrived. So far it sounds great with HD650. Have the class A bias and dual opa627 for later use also.


----------



## DjAmTraX

How's the build quality? Sharp edges? Solid knob and jacks? How many days to arrive?


----------



## Majestyk

panda-R: That photo is perfect for page 1.   Any chance the OP can use it and sub it for the current one?


----------



## panda-R

sure as long as I get royalties for each view of the photo I'm cool with that.


----------



## DjAmTraX

Someone please school me. Is the "premium" version even better than the Lehmann BCL?


----------



## panda-R

Quote: 





djamtrax said:


> How's the build quality? Sharp edges? Solid knob and jacks? How many days to arrive?


 


  3+ weeks. Solid Knob and Jacks. Crappy supplied power cable and/or receptacle. Will try another cable later. Edges are fine and the build inside is clean and detailed. So far I really like the sound with the HD650s. It has taken some of the darkness away from them.


----------



## tyoung8

Quote: 





djamtrax said:


> Someone please school me. Is the "premium" version even better than the Lehmann BCL?


 

 No.  Premium is just the assembled name of the LC.  LC is a clone of BCL at a 1/3 of the price.  I expect the BCL will beat the LC and the question is by how much.


----------



## kn19h7

Quote: 





djamtrax said:


> The LC:
> 
> 
> 
> Lehmann BCL:


 
  The transformer and volume control part looks so different, plus BCL is fully discrete (if I'm correct..) while LC is using OPA627, they may sound quite different.


----------



## Mad Max

BCL uses OPA2134.


----------



## sunneebear

Quote: 





kn19h7 said:


> The transformer and volume control part looks so different, plus_ BCL is fully discrete_ (if I'm correct..) while LC is using OPA627, they may sound quite different.


 


 You are mistaken.  That is just some wordsmithing used by Lehmann in their adds.  It uses an opamp also, just soldered to the board so you can't swap opamps.


----------



## kn19h7

^ aha, was suspecting that too by looking at the pic, actually the 'fully discrete' is seen somewhere else during google-ing but not on the official site.
   
  ..and oops, the LC is also using OPA2134, OPA627 is the upgrade kit.. my bad


----------



## sunneebear

Your info is correct.  I think Lehmann changed the wording on their site after a few audio sites including HF made note that with the use of a opamp, the circuit could not be "fully discrete".


----------



## Majestyk

Quote: 





> The transformer and volume control part looks so different, plus BCL is fully discrete (if I'm correct..) while LC is using OPA627, they may sound quite different.


 
   
   
  There is a different transformer option for the LC:
   
http://www.alicemagicbox.com/lasercollection/talema30va.html


----------



## panda-R

Here's the inside of my Lovely Cube premium. The premium version comes with the 30VA Toroid, the higher quality gold plated neutrik jacks, and higher quality RCA jacks. I opted to upgrade the RCA's to all copper units like some other guy here because they look so cool! Stephen also sells stepped attenuators but since I hate clickies I didn't bother but for $10 dollars it's a pretty good deal.


----------



## Majestyk

Does anyone know if the LC is suitable for driving AKG K-240 600 ohm headphones?


----------



## spidey

panda-r said:


> Here's the inside of my Lovely Cube premium. The premium version comes with the 30VA Toroid, the higher quality gold plated neutrik jacks, and higher quality RCA jacks. I opted to upgrade the RCA's to all copper units like some other guy here because they look so cool! Stephen also sells stepped attenuators but since I hate clickies I didn't bother but for $10 dollars it's a pretty good deal.




Very nice!


----------



## DjAmTraX

Got a response from Stephen. No review sample for me.  maybe I'll buy one.


----------



## panda-R

Quote: 





djamtrax said:


> Got a response from Stephen. No review sample for me.
> 
> 
> 
> ...


 


  that's a good idea! I'm sure you will like it if u like the BCL


----------



## BlaBlaBla

BCL and LC have same topology. As I tried to explain (more than 10 times), they have the same circuit topology, and that will (usually) give you similar sound. What I see on pictures is that BCL uses "audiophile" connectors (RCA and headphone out) that costs a lot. Also has better transformer. BUT IF YOU buy transformer on your own, and choose other parts on your own, YOU ARE ABLE *to make* EXACTLY THE SAME *amplifier* as BCL is, and *spend* LESS MONEY (THIRD - to be correct).
   
  "Darkness", "lightness", "slow", "fast" etc... depend on all internal parts in your BCL/BC,  INCLUDED EXTERNAL EQUIPMENT like cable, DAC and how well is sound recorded. For example, BAD recorded music will sound like CRAP on good system, and GOOD recorded music will sound GOOD on cheap system.
   
  I would like to see a person, in this world, who has approved explanation that two same topology, with same parts, on the same system, *with different name* (Black Cube Linear and Home Made Amplifier ) - could sound different.
   
  In this case, difference is because of few different components! Put on the paper the list of all BCL parts and I bet that, on Farnell or silimar site, you can assemble the same BCL for 300 USD!!!
   
  BCL and LC sound different because their components are different (said before). But difference is, maybe, 50 USD (not 600 USD!!!). What I am trying to say is that you can "tune" your sound to be the same as is in BCL - for less money (a lot)!!!
   
   
  LC Premium? It is LC "Normal" with high quality connectors. Two gold platet jacks will not change sound too much. Better spend money on mil. spec transformer, or transformer used in medical equipment - If you want to "hear" the difference...
   
   
  Sorry for bad english.


----------



## BlaBlaBla

I made parts list for LC, just as an example.
   
  1.   30 (0.25W) resistors - Takman REY - 20 USD
  2.   8 (1W) resistors - Takman REC - 10 USD
  3.   8 capacitors (Vishay ERO MKP) - 16 USD
  4.   2 capacitors (Mundorf MKP) - 7 USD
  5.   2 bulk capacitors (Mundorf SI/PI) - 30 USD
  6.   1 Alps POT - 20 USD
  7.   2 regulators - 7 USD
  8.   10 BC 550/560 - 5 USD
  9.   10 BD 139/140 - 10 USD
  10. 1 Transformer - 50 USD
  11. 1 Metal box - 50 USD
  12. Neutrik and RCA jacks - 20 USD
  13. Wire - 10 USD
  14. PCB board - 20 USD
  15. 6 heat sinks - 10 USD
  16. Other stuff - 50 USD
  -------------------------------------------------------
  = 335 USD
   
  335 USD << 1100 USD


----------



## Loevhagen

Just out of curiosity; why does the LC Premium cost USD 225 + shipping? Are the parts listed reflecting the de facto Premium version sold, or is it the fact that buying these parts 1-by-1 makes the total price 50% above the already assembled LC Premium?


----------



## BlaBlaBla

Quote: 





loevhagen said:


> Just out of curiosity; why does the LC Premium cost USD 225 + shipping? Are the parts listed reflecting the de facto Premium version sold, or is it the fact that buying these parts 1-by-1 makes the total price 50% above the already assembled LC Premium?


 

 Parts listed above are just for comparison for people who do not know how much BCL will cost them if they want make it at home. And use quality parts.
   
  There is no connection between LC Premium and parts stated above.
  Or if you want it simple: "Mundorf, Takman and ERO MKP, you will not find in LC." And, yes. They are expensive. Do you really need them? In 200 USD amp - no. In 1000 USD amp - YES.


----------



## Loevhagen

Ah. Thanks.
   
  So in order to spoonfeed: If someone wants to make a BCL *clone*, in the most stringent way, the price would be USD335. And; the difference in components in the LC Premium and BCL will not have an audible effect (if we interpret the LC to be a 95% replica of the BCL).
   
  It is the latter that I´m struggling with, since my initial impressions from reading this thread, is that the LC and BCL sounds the same, or lack of posted comparisons that is...


----------



## DjAmTraX

When I see the word "clone" I assume that every parts are the same. Otherwise, it would be a copy. Am I wrong?


----------



## BlaBlaBla

Quote: 





djamtrax said:


> When I see the word "clone" I assume that every parts are the same. Otherwise, it would be a copy. Am I wrong?


 

 No. They are not "clones". If you look closely you will see difference. But as I said before, 80% of amplifier is the same.
   
  Just do not be scared about amplifier. Buy it if you want it. Probably, you will not make wrong decision. And if you do, you will spend 700 USD less.


----------



## ringer

Second stage for my LC is on it's way 
	

	
	
		
		

		
		
	


	



   

   
  LC will be used as preamp. And this 5 W per channel amp will be used for speakers and headphones which is hard to drive.
  There's original schematic http://diyaudioprojects.com/Solid/ZCA/index.htm I simply throw away potentiometer, and will make more powerful and clean power supply.


----------



## gwikse

Spoonfeed: no the LC premium is closer to the BCL than the part list that BlaBlaBla listed (those parts would improve an original BCL).
 The closest you get atm to a clone is the LC premium at USD225
  
  If you then change the caps to Philips BC 4700, 470`s and wima MKS2 in the power section you would have a clone. But then again I would go beyond the bcl with better caps and resistors like BlaBlaBla listed. No matter how you look at it, the LC is a bargain.
  Quote: 





loevhagen said:


> Ah. Thanks.
> 
> So in order to spoonfeed: If someone wants to make a BCL *clone*, in the most stringent way, the price would be USD335. And; the difference in components in the LC Premium and BCL will not have an audible effect (if we interpret the LC to be a 95% replica of the BCL).
> 
> It is the latter that I´m struggling with, since my initial impressions from reading this thread, is that the LC and BCL sounds the same, or lack of posted comparisons that is...


----------



## tyoung8

Which of those parts would require upgrading most - sound wise?


----------



## BlaBlaBla

Quote: 





tyoung8 said:


> Which of those parts would require upgrading most - sound wise?


 

 I think you should try to remove 470uF capacitors and lower Cout capacitors (after regulator) as much as you can (without oscillation). Cout = 22nF. I heard that big capacitors tend to smear signal, (make them more slow than usual).
   
  But I suggest that you use electrolytic capacitors (fast one) on OPAMP and bypass them with good MKP. OPAMP does not like supply ripple. It has to have steady +/-14V.
   
  That is what I am going to do next. But I have to wait PCB-s...
   
  If you want to tune your sound then big influence have bypass capacitors and electrolytic capacitors on output (near BD transistors).
  Also big influence on sound have DC blocking capacitors, and there I suggest you to use the best one that you can put there. Or none. But be aware of DC signal that might send your headphones "to meet their maker".


----------



## khatch

I've owned both the BCL and the LC.  They didn't sound the same.  What am I to infer from that?


----------



## ringer

Quote: 





tyoung8 said:


> Which of those parts would require upgrading most - sound wise?


 
  Four caps in the input of signal part.
   
  The best choice is paper with oil 1.5uF caps (Jensen for instance). As for 22nF, I think it's not useful.
   
  Or you can throw away all this caps and use the wire instead. It gives you the most transparent and wide sound, and it costs you nothing. But you have to be sure that DAC which you used with LC don't produce DC in the output.


----------



## aspenx

Quote: 





khatch said:


> I've owned both the BCL and the LC.  They didn't sound the same.  What am I to infer from that?


 


  That you probably have very good ears and other gear (and music) that can resolve very well?
   
  I wished I have both too to try it out with my gear myself...
   
  Oh well.


----------



## tyoung8

oops is kinda gone way over my head.    I thought when I get to buy, I'll just email the guy and tell him to upgrade x parts with y parts and install it for me.  Like the OPA 627 upgrade for $12 option.


----------



## tyoung8

Quote: 





ringer said:


> But you have to be sure that DAC which you used with LC don't produce DC in the output.


 

 Would the matrix mini i or the little dot DAC 2 be a good fit with the LC?


----------



## DjAmTraX

tyoung8 said:


> oops is kinda gone way over my head.    I thought when I get to buy, I'll just email the guy and tell him to upgrade x parts with y parts and install it for me.  Like the OPA 627 upgrade for $12 option.



+1
this is way I think too much choices is not good. Way over my head on all the options one can get.


----------



## BlaBlaBla

Quote: 





tyoung8 said:


> Would the matrix mini i or the little dot DAC 2 be a good fit with the LC?


 

 I have Matrix Mini I and it is good choice unless you have something better. For example, Matrix Mini I is better than USB EMU 0404. EMU is too sterile.


----------



## panda-R

Quote: 





tyoung8 said:


> Would the matrix mini i or the little dot DAC 2 be a good fit with the LC?


 


  I am using Matrix Mini-I to the lovely cube with OPA627 and I really like this combo. You wont' be disappointed.


----------



## panda-R

Just received my Beyer DT880/600s and so far they just make my love my HD650/LC comobo even more. They're brand new so I still have hope they will open up more with use.


----------



## Heidegger

Quote: 





majestyk said:


> I was reading on another forum that the Sennheiser HD800's don't sound very good with the M-Stage but do with the Black Cube.  I'm wondering if anyone is using these headphones with the Lovely Cube and if it's handling them well.  If so, I think it could be a good testament to how similar the LC and BCL are.
> 
> Link:
> 
> ...


 

 I have exactly the same experience with the BCL as the guy who wrote the article. Fast transients and an amazing job with percussion.


----------



## BlaBlaBla

Sennheiser? LOOOOL! 
   
  Usually they were able to give "some kind of noise", and "from the bottom of the well" voices - as something extra.
   
  And now I read that they can do more. Good for Sennheiser... For almost 1k USD, advancement is obvious.


----------



## Heidegger

Quote: 





blablabla said:


> Sennheiser? LOOOOL!
> 
> Usually they were able to give "some kind of noise", and "from the bottom of the well" voices - as something extra.
> 
> And now I read that they can do more. Good for Sennheiser... For almost 1k USD, advancement is obvious.


 

 This seems to have been lost in translation. I don't understand what you're saying here.


----------



## Mad Max

Quote: 





heidegger said:


> Quote:
> 
> 
> 
> ...


----------



## aspenx

I think he means to say that he's not a big fan of Sennheiser.

  
  Quote: 





heidegger said:


> This seems to have been lost in translation. I don't understand what you're saying here.


----------



## panda-R

Quote: 





aspenx said:


> I think he means to say that he's not a big fan of Sennheiser.


 

  
  thats unfortunate because Sennheiser is awesome and the combo with LC is awesome!


----------



## BlaBlaBla

Quote: 





panda-r said:


> thats unfortunate because Sennheiser is awesome and the combo with LC is awesome!


 
   
  Sennheiser are great headphones.
   
  ATH is king of sound stage.
   
  But Grado...
   
   
  ...It rules!!!!


----------



## panda-R

Which grado should i buy? RS1i?


----------



## BlaBlaBla

Quote: 





panda-r said:


> Which grado should i buy? RS1i?


 

 No. Why? You should try SR 60 or SR 225 or RS2. People say that those three tend to color the sound slightly what gives "the unique Grado sound".
   
  Sennheiser are very good but I do not like two things. First, they are close to AKG K701, that are kings of technical perfection (I call that "sterility"). Sometimes, imperfection is good because it is something like a unique character of sound. You might not love it. But I do.
  Second what I do not like is that AKG 7xx and Sennheiser 6xx need BIG amplifier. That means that if you do not have strong and good amp you will not hear a "true potential of your headphones". Without a good amplifiication, Grado or ATH might give you better results and better clarity than Senn or AKG.
   
  I was able to hear and compare AKG K701 with Grado SR225 on Matrix M Stage. AKG had superior sound stage but I used to have feeling that something was missing... In very demanding concerts with many instruments AKG muffled a lot. But not because itself, but because Matrix M Stage was "not enough good amplifier" and Matrix DAC too.. The same thing goes with Lovely Cube. With Grado things are different. Grado is not able to achieve such a big sound stage, and it is not so wide. But degradation is very low or almost close to none!  Also, dynamic is better on more demanding music, because Grado is driven more easily. The same goes for ATH.
   
  I always say, if someone has enough money for hand made (>2000 USD) amplifier (Not Lehmann or similar stuf, but REAL DIY amplifier) then AKG K7xx or Senn 6xx will reveal more details. But here we are talking about hand made amps that cost less than 300 USD!!! I know people (here in Croatia) who were making preamplifiers, DAC-s and cables on their own, and they say that headphones over 500-600 USD are so good that true potential can be revealed, only when entire system is carefully built (with carefully choosen parts - here we are talking about sky high 5 000 USD and more...) Also, recordings have to be the best. Not some Mp3 crap, or 100 times burned CDs.
   
  Usually, the difference that we hear is only because the coloration made by our systems. There is no ideal system. And when I read something: "This headphones have flat characteristic. So sound must be perfect!" it reminds me how blind (deaf) can someone be. Because there is no flat characteristic. It does not exist! Especially when in that story are involved lots of components. It is not a point to have headphones with flat characteristic. It is a point to know what kind of characteristic will give you headphones with DAC, cables and amplifier together. And that information is reserved for people who have proper measuring equipment, witch price has many zeroes.


----------



## panda-R

thanks buddy for your opinion... i think I will try Grado sr225is one of these days, but now i need to enjoy my HD650 and LC combo.


----------



## Mad Max

Quote: 





blablabla said:


> ...  Usually, the difference that we hear is only because the coloration made by our systems. There is no ideal system. And when I read something: "This headphones have flat characteristic. So sound must be perfect!" it reminds me how blind (deaf) can someone be. Because there is no flat characteristic. It does not exist! Especially when in that story are involved lots of components. It is not a point to have headphones with flat characteristic. It is a point to know what kind of characteristic will give you headphones with DAC, cables and amplifier together. And that information is reserved for people who have proper measuring equipment, witch price has many zeroes.


 

 Indeed, but you're not listening to your system as a whole if you are rolling opamps, cables, headphones, and so forth and listening to the changes to deduce a component's _relative_ individual character.
  Much cheaper than using expensive measuring equipment that can hear things that our flawed ears cannot.  =p


----------



## tyoung8

I really love the Grado 225 for rock as it makes the music so in your face and fun sounding.  The only problem is that I think maybe with 'forward' headphones, I would find it v fatiguing to listen for time... at least that is the case with my Superlux 662.  Wonder if that is true for Grado headphones as well?
   
  Quote: 





panda-r said:


> I am using Matrix Mini-I to the lovely cube with OPA627 and I really like this combo. You wont' be disappointed.


 

 yep, that is deffo the combo I am angling for at the moment.


----------



## BlaBlaBla

endas
  
  Quote: 





tyoung8 said:


> I really love the Grado 225 for rock as it makes the music so in your face and fun sounding.  The only problem is that I think maybe with 'forward' headphones, I would find it v fatiguing to listen for time... at least that is the case with my Superlux 662.  Wonder if that is true for Grado headphones as well?
> 
> 
> yep, that is deffo the combo I am angling for at the moment.


 

 True. OPA627 is good opamp. It has warmth and deep soundstage. I tried it with ATH AD900 and it is better match than with Grado SR225. ATHAD900 do not have deep sound stage, but wide. And they have good synergy (space wise) with OPA627.
   
  Grado SR225 do not have wide sound stage and they sound (on OPA627), deep but closed. For Grado, better match is OPA2107.
   
  I think that Matrix Mini I has warm sound stage, and lack of details. I feel that Matrix with OPA627 tends to behave in the same way (if we compare it to more bright OPA2107). So I go towards OPA2107 because I am always trying to find good combination between "bright and detailed" and "warm and mellow" components. I also think that OPA627 shines in old school amplifiers paired with very detailed DACs, because it gives to the sound more warmth and sweetness and masks harsh and sterile approach straight from the DAC output.
   
  Sorry for my bad english.
  I do not have time to recheck what I have allready written.


----------



## BlaBlaBla

I changed OPA627 with LME49720HA. Metal case.
  That opamp is good. Very good.. Maybe too bright in combination with Grado SR225, but shows a lot more details than OPA627AU and OPA2107. Drawback is total absence of warmth, that have all BB opamps. Sound stage is between OPA2107 and OPA627. Positioning is good.
   
  I have to wait 10 or 20 hours of playing to see more...
   
   
  What comes first on my mind is that LME could be great with "dark headphones". So people who have Sennheisers or something like that they should try LME47920HA. It is totally different world than all Burr Brown OPAMPS...


----------



## tyoung8

Yeah, I am looking for warmer dac because ultrasones are kinda cold.  Does anyone know what the little dot dac 2 sounds like?


----------



## BlaBlaBla

Quote: 





blablabla said:


> I changed OPA627 with LME49720HA. Metal case.
> That opamp is good. Very good.. Maybe too bright in combination with Grado SR225, but shows a lot more details than OPA627AU and OPA2107. Drawback is total absence of warmth, that have all BB opamps. Sound stage is between OPA2107 and OPA627. Positioning is good.
> 
> I have to wait 10 or 20 hours of playing to see more...
> ...


 

 I just do not get it... Maybe my OPA627 was "a lemon", or something, but difference is more than huge... LME really shows details. And it has excellent freqency range when music is well recorded!
   
  I do not know... LME was from Great Britain. OPA627 was from China... Is the difference that big?


----------



## Mad Max

Quote: 





blablabla said:


> ...OPA627 was from China...


 






  Grab a real pair next time.  However, try OPA209, OPA1611, THS4081, and OPA827 before that, tells us what you think of them.


----------



## BlaBlaBla

All these are SOIC type. I do not want SOIC opamps.


----------



## Mad Max

But the best opamps are mostly SOIC type.  =\
"It can't be helped."
  I would like it if they were DIP, then I wouldn't have to solder them to adapters.


----------



## BlaBlaBla

Quote: 





mad max said:


> But the best opamps are mostly SOIC type.  =\
> "It can't be helped."
> I would like it if they were DIP, then I wouldn't have to solder them to adapters.


 

 You see, problem is that SOIC type opamps are very sensitive to heat. If you use solder wire and solder them in usual way, there is great chance to break them (overheating). Usually my soldering tool has temperature over 300/350 °C. I use "warm and fast" technique. And if I solder with lower temperature (more safety approach) then I have to wait too much.
   
  With DIP 8 type I have never had a problem, because I solder DIP 8 socket, and then I insert opamp into socket. Also SMD resistors, capacitors and other fancy stuff is prone to failure because overheating. But old fashion capacitors, carbon resistors, metal can opamps and transistors can work in very harsh environment. I can almost weld them onto PCB!!! 
   
   
  The best way to solder SOIC on the PCB (or adapter) is to use flux and heater. Spread the flux over contacts on PCB, put SOIC on PCB (on spreaded flux) and heat up all that. SOIC pins will be "glued" to PCB.  But I do not have that kind of equipment. And it is not cost wise for me, buying equipment that cost 250 USD, for soldering (once in a year) two SOIC opamps that cost 5 USD each.


----------



## Mad Max

I don't use temperatures that high with my Hakko 936, Cardas quad eutectic melts very fast, and together with liquid solder, I can work very quickly without damaging opamps.
  I damaged soic chips in the past with overheating, but that was a long time ago.  Practice makes perfect.  =]


----------



## BlaBlaBla

An hour ago I was trying to figure out why DC offset likes to oscillate (1-2mV) when LC is not warm. Now I know why. 
   
  I tried to touch metal cap of BC139C with a cold screw driver (it acted like a cooler), and when I did that - DC offset jumped from 2mV to 6 mV.  At first point it looks like extra cooling is not good for BC-s. But it is not true. Cooling is good, but not when you are trying to cool only one transistor.
   
  Important thing is how good is temperature spread over entire case over all transistors.All transistors must have the same temperature. So, when one BC139 (in my case) works on 100°C (and it does - working temperature for BC109/139 is 80-125°C), that means that all other BC-s must have the same temperature. Otherwise DC offset will raise sky high. It does not matter if your amplifier case is warm like stove, or it barely shows that is turned on. Important is that all transistors in it, must be equally heated/cooled! Also, I noticed that transistors with high gain are more dependent on temperature than transistors with lower gain...


----------



## Majestyk

I recently bought the LC Premium and I'm just getting around to it today.  I can't get any sound.  Is there anything I'm missing?  The blue light is on, the L&R lights, on the board, are on.  I have the CD player hooked to the input jacks.  (The outer most left ones, correct?).    Is there anything else I'm missing?  Nothing on the headphone/CD player end is the problem.
   
*Never mind, user error on my part.  All is working 100%.*


----------



## Majestyk

Does anyone know how difficult a fix this is?  As you can see the little round metal 'fixture', on the board, is completely out.
   
  UPDATE...Yes this can be easily soldered underneath.


----------



## Majestyk

http://cgi.ebay.com/LME49720HA-LME49720-TO99-DIP8-/190523359451?pt=LH_DefaultDomain_0&hash=item2c5c13c0db#ht_792wt_1144
   
  Can anyone tell me if this LME49720 works with the LC?   If so, do I need one of those little heat sinks for it?


----------



## Mad Max

Totally. Heat sink?  I doubt it.


----------



## Majestyk

If you go to this link and scroll down just a tiny bit, you'll see the heat sink.  Maybe it's for something different...Dunno.
   
http://www.alicemagicbox.com/lasercollection/lovelycube.html
   
  BTW, too bad the OPA-Earth doesn't easily fit in the LC.  A lot of people in the M-Stage thread are raving about it.


----------



## ninjikiran

If only plastic was a good conductor of heat , than again if I recall aluminum is cheaper...  Those are socket adapters not heat sinks.  The standard LME49720-HE has a TO99 pin arrangement, where the standard for most op-amps used in audio are Dip8 or SOIP.  What you see there is a TO99 seated in a Dip8 adapter.
   
  Best results would be to create your own circuit board so you could natively solder it directly onto the board but that is not a weekend project.
  Quote: 





majestyk said:


> If you go to this link and scroll down just a tiny bit, you'll see the heat sink.  Maybe it's for something different...Dunno.
> 
> http://www.alicemagicbox.com/lasercollection/lovelycube.html
> 
> BTW, too bad the OPA-Earth doesn't easily fit in the LC.  A lot of people in the M-Stage thread are raving about it.


----------



## BlaBlaBla

Quote: 





majestyk said:


> http://cgi.ebay.com/LME49720HA-LME49720-TO99-DIP8-/190523359451?pt=LH_DefaultDomain_0&hash=item2c5c13c0db#ht_792wt_1144
> 
> Can anyone tell me if this LME49720 works with the LC?   If so, do I need one of those little heat sinks for it?


 

 LME49720HA is excellent choice.It is very fast (I mean VERY FAST) and wide band opamp, and more prone to oscillations. It needs good coupling capacitors and demands good source (DAC) - without crap in signal.  If you want to compare to OPA2107 or OPA627 - don't. It does not forgive...  It demands the best signal on input or it will show you every crap in your recordings.
   
  It goes hot (metal version) so TO-5 heat sinks are recommended.
   
  Do not worry. It will sit in your DIP8 socket. I have LME49720 HA and there is no problem. You should use good socket (Nextron or similar stuff - not some "gold plate" fancy stuff).


----------



## ringer

*Majestyk *
  You can solder in this wire at the bottom.


----------



## Majestyk

Regarding the 'heat sink'..Ok my bad.  HAHA.
   
  As for the wire, that's what I was thinking.  I'll still have to get someone to do this.  Everything has to come out to do it and my soldering skills aren't perfect.
   
  Quote: 





> LME49720HA is excellent choice.It is very fast (I mean VERY FAST) and wide band opamp, and more prone to oscillations. It needs good coupling capacitors and demands good source (DAC) - without crap in signal.  If you want to compare to OPA2107 or OPA627 - don't. It does not forgive...  It demands the best signal on input or it will show you every crap in your recordings.
> 
> 
> 
> ...


 
   
  Since I'm at novice at this stuff, I'm not following this 100%...So can I use the LME49720 without doing any other modes to the LC Premium?  In other words, can I just drop it in the socket?  Thanks!


----------



## BlaBlaBla

Of course! 
  
  Quote: 





majestyk said:


> Regarding the 'heat sink'..Ok my bad.  HAHA.
> 
> As for the wire, that's what I was thinking.  I'll still have to get someone to do this.  Everything has to come out to do it and my soldering skills aren't perfect.
> 
> ...


----------



## panda-R

this amp is not appreciated enough!
   
  I am still enjoying mine with the OPA627!


----------



## ringer

I'm appreciated  I even made single ended pure class A amp for using LC as a preamp.
  But I don't very much like OPA627 with LC. I think 2134 and 2111 are better.


----------



## BlaBlaBla

Quote: 





ringer said:


> I'm appreciated  I even made single ended pure class A amp for using LC as a preamp.
> But I don't very much like OPA627 with LC. I think 2134 and 2111 are better.


 

 Tried OPA2111 (bought in USA). Maybe slightly too dark and thin.  But man, vocals are *stunning*!


----------



## panda-R

Quote: 





blablabla said:


> Tried OPA2111 (bought in USA). Maybe slightly too dark and thin.  But man, vocals are *stunning*!


 

 NICE,
   
  where did u find it?


----------



## Heidegger

I want to buy one of these Lovely Cubes so I can compare it with my BCL. I'm not a DIYer, but I understand I can buy it assembled. Does the guy who sells this offer different opamps or will I have to do it myself?


----------



## panda-R

it comes with the 2134, you can get the dual 627 and the 2111AM(UK) from him.


----------



## BlaBlaBla

On e-bay. USA seller.
   
  Quote: 





panda-r said:


> NICE,
> 
> where did u find it?


----------



## BlaBlaBla

My second LC is finished. Pictures of the board - tomorrow.
   
  It took ten hours until everything settled in, and until it started to sing like I expect...


----------



## ringer

This is the best mode I have made for LC.
   

   
  I don't know why they put 1.5uF in the input. If you put more capacitance you will fill the difference. The frequency response will not change, but bass will be better. And there will be less noise when attenuator on height position. I've used 8.2uF, but I think 22uF will be even better.


----------



## BlaBlaBla

Quote: 





ringer said:


> This is the best mode I have made for LC.
> 
> 
> 
> I don't know why they put 1.5uF in the input. If you put more capacitance you will fill the difference. The frequency response will not change, but bass will be better. And there will be less noise when attenuator on height position. I've used 8.2uF, but I think 22uF will be even better.


 


  Nice work!
   
  Mine looks like this...
   

   
   
  I agree that bigger capacitors in input, are better. Bass is much better.
   
  I made something unusual. All resistors are PRP, except those in output. I do not know but I think that output resistors are something like Riken Ohm RM or Allen Bradley. I bought 50 pcs and all of them have exactly 10.1 Ohm resistance, which is impressive for such an old product.
   
  There are two ERO KP 1837 (0.1uF) after regulators, four Panasonic FC (680uF) on output, two Nichicon Muse (22uF) and two polystyrene as coupling (10 nF).
   
  In input there are two ERO MKC 1862 (4,7uF) and two AEL polystyrene (31 nF),  as input filter I use two FSC Styroflex (100pF).
   
   
  Transistors are stock BC550/560 and matched BD139/140 (believe me I do not see any improvement over unmatched trensistors).
   
   
  First few hours amplifier was mellow and restricted on highs. But now things are different. It is unforgiving for bad recordings.


----------



## ringer

Thanks 
	

	
	
		
		

		
			





 Yours looking good to 
   
  I'm not sure, but I think unmatched transistors could be cause of rising DC in the output and some increase of distortion, but it might be not noticeable because it less then headphones distortion.
   
  Why you use 31nF caps in the input? I think it will be batter to use only one as good as possible then two (IMHO).
   
  Also try to move transformer as far as possible from signal wires and board. Even half centimeter will reduce noise significantly.


----------



## gwikse

Looks very nice. You should try to change all the fixings and screws to brass. Start with the transformer mounting. This little tweak has so far allways led to better sq in all my components. I am waiting for larger trannies as well (80VA).  I still have a lot of work to do before I mount it all in its final chassis.


----------



## BlaBlaBla

Quote: 





ringer said:


> Thanks
> 
> 
> 
> ...


 
   
  Thanks! 
	

	
	
		
		

		
		
	


	



  I will try that when I find better (bigger) box for amp. (I think that I have a few metal boxes somewhere in the house...) Bigger transformer is my next goal. 80 - 100VA is way to go. This enclosure is too small, tight, and heats too much. That is not good for polystyrene-s and MKP-s. 
   
  I tuned DC offset with Radj on LM regulators. I always use Radj because it is hard to find good regulators which have the same heating "offset". Also it is hard to find PNP and NPN that have the same hFE. On this setup (550/560C) I achieved 2-3 mV offset when I tuned LM317 on + 14.8V, and LME337 on - 14.1V.
   
  I have another LC amplifier with different transistors 139/109C. And there, offset is smaller (1-2 mV) when voltage is - 14.3V and + 14.25V. I have feeling that those old metal transistors have better temperature characteristic than this new, made of plastic... Well, who knows...
   
  It is true. Less capacitors in a circuit is better. I will try two big MKP-s when I get them. I put polystyrene caps because I tried to make sound more colored in a way that I like. Without polystyrene sound was, slightly, too bassy and mids too dark. Polystyrene caps brightened up sound stage. I like trying different components (capacitors, opamps, transistors). It is interesting how they change final picture of the sound. But it takes time because every component needs burn in time (that is usually 10 hours of playing).
   
  I connected cable coatings directly to ground. On Grado and ATH headphones, at max volume, I barely hear transformer hum. But that would blow my ears anyway. Grounding is very interesting and important in audio circuits. I was reading something about different resistor values in the ground loop and how they can direct parasitic current to bypass crucial circuits and components... I am interested in grounding technique, but do not have time to study it. Too much to do, and too little time.


----------



## ringer

Quote: 





blablabla said:


> Thanks!
> 
> 
> 
> ...


 
  Try to move transformer in this box. It's not necessary to screw it symmetrically. Take a look on my photo.
  
  2-3mV is an excellent result! Even ten times more is OK 
   
  Look at my addition for LC 
	

	
	
		
		

		
		
	


	



  This is heavy duty 5W single ended class A amp. With 200W transformer on board. The circuit by Mark Houston http://diyaudioprojects.com/Solid/ZCA/ZCA.htm
  I'm using LC as preamp for listening MBQuart 450 headphones. The sound starts to be more natural and balanced. Sound signature no more bright. The mid-low and low range are very good and precise. It seams that MBQuart 450 likes to be driving by height power. Compare to this thing LC is cold as snow in winter ))


   
  Trying to make some dinner


----------



## francisdemarte

Quote: 





ringer said:


> This is the best mode I have made for LC.
> 
> 
> 
> I don't know why they put 1.5uF in the input. If you put more capacitance you will fill the difference. The frequency response will not change, but bass will be better. And there will be less noise when attenuator on height position. I've used 8.2uF, but I think 22uF will be even better.


 


  Nice! Reminds me that I have a couple of old Vitamin Q Oil and Paper caps I want to try in this position! Will report back with pictures


----------



## T.IIZUKA

Quote: 





blablabla said:


> Mine looks like this...


 

 What does the output resistance use?
   

   
  I switched to DALE CW-2B.
   
   
  A former pic.


----------



## francisdemarte

I heard it was bad to use the center screw of your torodial transformer as a ground point.


----------



## gwikse

My "stock" lovely cube has been running for a long time now. Used two in a balanced config but screw up one when trying to remove some parts. So next step (if I deside to stay with the lc) is to max out two with better parts (matched and so on) or just tweak a little on the one I allready have (change the input caps). I used mundorf supreme solder, fairchild voltage regulators and 139/140 as well as BYV27-150`s and a 80VA transformer on the one I`m using now. Audio-GD opa earth is also great in my system. I`m using a hifi2000 [size=x-small]1NGXA288N case [/size]so space is not an issue. Have not drilled out the front plate yet though so it all looks a little diy`ish atm...
   
  Been running it with a TPA Buffalo II - legato 2 DAC the last few days and I am as close to audio nirvana as I have been for quite some time (must go back to during my crazy Burmester + Audiophysic days).
  Bought a set of T1`s and the last few days the system has stopped being a system, and started to do its job well enough to make me fokus on the music, movie, sports or whatever. Lovely cube indeed


----------



## gwikse

After this experience I pulled the trigger on a fully balanced beta22 with sigma22 psu. Should be ready sometime this summer. The lovely cube will be mated with my Matrix mini-i on the rear of my computer screen (I`m making a chassis to be mounted to the screen`s vesa holes).
   
  I have to do something with my dc offset though. the 10mV - 3mV I have now is "ok" with my 600ohm T1`s but will be too much on my DT770-80. Oh well trimpots on the way I guess


----------



## hifienthusiast

The headphone output of my Blackcube Linear clone is silent but when I use the line output to my Quad 306 power amp, there is a constant hum through the speakers. What is the cause of this hum through the line output? Could it be the body of the Alps pot not being grounded properly?


----------



## gwikse

Cable to the pre-out too close to the transformer will cause hum. If it were the alps pot you would also hear it when using headphones.


----------



## BlaBlaBla

I have three ground poins. First is metal case, second is ground on PCB, and third is central screw of transformer. No problems at all. With ATH and Grado, there is no hum.
  
  Quote: 





francisdemarte said:


> I heard it was bad to use the center screw of your torodial transformer as a ground point.


----------



## BlaBlaBla

Shielded cables. Both sides of shield have to be grounded, or both sides must not be grounded. If you ground only one side, you will have hum.
  
  Quote: 





gwikse said:


> Cable to the pre-out too close to the transformer will cause hum. If it were the alps pot you would also hear it when using headphones.


----------



## hifienthusiast

There is no hum through the headphone outputs.
   
  The signal cable is a good quality one made by Linn. Using the Linn signal cable, there is no hum from a Creek passive pre amp to the Quad 306 power amp.
   
  My Blackcube clone was not made by myself, I will need to open the cover to find out the grounding scheme.


----------



## francisdemarte

Does the hum change to go away when you wiggle the RCA cables? Does it go away when you touch the volume pot or change the volume?


----------



## hifienthusiast

The hum does not go away when I wiggle the signal cable, I have even changed the cable to make sure. The volume pot does not affect the hum, the level of hum is constant through the Quad 306 power amp and speakers.


----------



## BlaBlaBla

Quote: 





hifienthusiast said:


> The hum does not go away when I wiggle the signal cable, I have even changed the cable to make sure. The volume pot does not affect the hum, the level of hum is constant through the Quad 306 power amp and speakers.


 
   
  Does your Quad 306 power has power cord with three wires (separated ground) or with two (without ground)?
   
  Because if it has two wires and your Lovely Cube has three (ground) - then hum will be always there. You can ground your Quad, or you can remove out third wire from Lovely Cube.


----------



## BlaBlaBla

I replaced resistor R2 in regulators circuit (LM317/337) with two zener diodes (13V, 1.3W). First I was against that, because I did not know how high DC offset would be. Some people say that in their Lovely Cube offset goes above 10 mV... But now, I am satisfied.
   
  Here, DC offset is low enough.


----------



## taiyoyuden

There are two headphone jacks. Is there a difference between them? Can they be used simultaneously? If so, is there a sound quality tradeoff?


----------



## francisdemarte

Yes there are 2 headphone jack on the pre-built model. There is no difference between them except one of them mutes the line-out and the other one does not.


----------



## alanbeeb

OK - bottom line folks - is this as good as a real Lehmann BCL? 
  Thanks.


----------



## francisdemarte

A couple of people did a comparison in this thread. I believe generally they sound a little different because of differences in parts such as the caps and opamps. Some preferred the BCL others liked the LC.


----------



## alanbeeb

Is switching Opamps easy - are they socketed or are desoldering/soldering skills required?


----------



## Wingstrike

Quote: 





alanbeeb said:


> Is switching Opamps easy - are they socketed or are desoldering/soldering skills required?


 


  I have a pre-built Lovely Cube Premium and it's socketed. Switching opamps is super easy


----------



## Nescafe

Deleted


----------



## alanbeeb

Just my 2 cents worth on the lovely cube.... I bought a 2nd hand one to try instead of the genuine Lehmann BCL (which I know well from being a previous owner and rate highly) and I have to say I am disappointed.
   
  Into the Sennheiser HD565 I am currently using (waiting for Denon AD5000 to arrive) the sound is hard, tizzy, lacking air and space and soundstage is compressed.  The headphone socket on my Sony SACD player does a much better job and is far preferable!
   
  I'll have a scan through here to find out about Opamp changes but at moment looks like I will not be keeping it.


----------



## francisdemarte

Quote: 





alanbeeb said:


> Just my 2 cents worth on the lovely cube.... I bought a 2nd hand one to try instead of the genuine Lehmann BCL (which I know well from being a previous owner and rate highly) and I have to say I am disappointed.
> 
> Into the Sennheiser HD565 I am currently using (waiting for Denon AD5000 to arrive) the sound is hard, tizzy, lacking air and space and soundstage is compressed.  The headphone socket on my Sony SACD player does a much better job and is far preferable!
> 
> I'll have a scan through here to find out about Opamp changes but at moment looks like I will not be keeping it.


 
   
  Let's see if it's possible to resolve some of these issues. Find out which opamp is in your LC. What gain setting are you using?


----------



## alanbeeb

Ok - thanks for the offer to help - I'll get back shortly with what I find.  I'm using highest gain setting +20db


----------



## alanbeeb

Quote: 





francisdemarte said:


> Let's see if it's possible to resolve some of these issues. Find out which opamp is in your LC. What gain setting are you using?


 

 Hi,  highest gain setting. The opamp appears to have been scraped or rubbed to remove markings - but I can see 45EXY on it. Here is a photo.
   

   
  any recommendations? thanks.


----------



## francisdemarte

Maybe someone else can chime in but I've never seen that opamp before. The fact that the makers markings are rubbed off also makes it suspect. I'd try picking up one of the ones suggested in this thread (lots of discussion in the first 10-15 pages) or the M-Stage thread from a trusted source.
   
  I think the one in the original Lehmann was the OPA2134. Here in the States this opamp runs about $3. A lot of people like the more expensive darker bassier OPA627. 
   
  Post up the type of music you like to listen to and hopefully other will also jump in with suggestions.
   
  In the meantime, you might also want to try playing with the gain settings a little to see if you get any improvements. Some opamps like a certain min/max level of gain to work at their best.


----------



## alanbeeb

Mainly classical orchestral and heavy rock for me.
   
  I have insignificant soldering skills. OK on a big wire but couldn't solder one of these things.... where can I get the opamp already mounted on an adapter? Thanks


----------



## francisdemarte

I'm not familiar with electronic vendors over in the UK. You might try RS.
   
  OPA2134PA in 8 pin PDIP format; which is drop in, no soldering:
   
http://uk.rs-online.com/web/p/op-amp/2858069/
   
  If you want to try some other drop in replacements:
   
http://uk.rs-online.com/web/c/semiconductors/amplifiers-comparators/op-amp/?sort-by=default&sort-order=default&view-type=List&applied-dimensions=4294884083,4294884089,4294883363&lastAttributeSelectedBlock=Supplier%20Package
   
   
  Tam's audio sells the a couple of opamps on adapters and with class A mods. You can get more reviews of this from the M-Stage thread:
   
http://tamaudio.com/store/index.php?route=product/product&product_id=82

  Personally, I'd try the OPA2134 opamp first, give your self some time to get used to the sound. If you still don't like what you hear then the LC just isn't a good match for you. You can probably resell it for close to what you paid.
   
  Good Luck!


----------



## Mad Max

Quote: 





alanbeeb said:


> Hi,  highest gain setting. The opamp appears to have been scraped or rubbed to remove markings - but I can see 45EXY on it. Here is a photo.
> 
> 
> 
> any recommendations? thanks.


 

 Let me help you, sir.
   
   





   
   




   
  OPA2134.  It's a jellybean, skip it and get a pair of AD797ANZ or OPA602BP and a socketed adapter to go with them.  These will give you more significant overall improvement in sound over most others.  OPA627 is very colored, and some people like it.


----------



## alanbeeb

Ah..... OK, in that case I've got another 2134 arriving tomorrow but also a 627 and 637. Will see how these go before trying more....
   
  P.S. Halle Berry Ha Ha - I've just been RickRoll'd! 
	

	
	
		
		

		
		
	


	




  (see vido link in Mad Max's sig)   25 years ago, people were telling me I was Rick Astley's twin brother. However I am a MUCH better dancer.


----------



## alanbeeb

Ok - the new 2134 that arrived today seems much better than the old one, no spitty grainyness that I was suffering before.   Overall its now slightly better listening experience than the headphone socket on my Sony CD..... which is still a disappointment tbh.  Or maybe the headphone out on that Sony is something special - but the real Lehmann BCL I used to own was clearly superior.
   
  I've tried the 627 and 637 - are these straight drop-in replacements?  Because I can't get them to work, sound is there but get almost no volume at all with them?  Am I missing a trick somewhere?


----------



## francisdemarte

The OPA627 and 637 are single channel so you'll need two of them on the adapter that Mad Max posted.


----------



## Zsubbo

What kinds of skills does one need to complete a lovely cube headphone amplifier kit? Is it enough if I can solder and understand basic electronics ?
   
  I'd like to get into DIY Headphone amp building, and this would be my first project.


----------



## francisdemarte

The Lovely Cube is semi-DIY. All you need is basic soldering and some knowledge on how to properly wire up a transformer.
   
  The board is completely populated, all you have to do is add the RCA inputs/outputs, transformer, and case it.


----------



## Zsubbo

I'd like to populate the board too, so I can get some practise, before building AMBs M^3, wiring the transformer and the rest should be no problem.


----------



## francisdemarte

Check out the kits at glassjaraudio.com. They have complete kits of the AMB amps, saves you the hassle of ordering from AMB,mouser,digikey etc.
  The Mini M^3 would make a great first amp project.
   
  Ebay has the "Panda" Amp, which is very close to the Lovely Cube, as a complete kit as well:
   
http://www.ebay.com/itm/HIEND-design-panda-headphone-amp-kit-/320743105306?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item4aadc7631a#ht_5817wt_905


----------



## Zsubbo

Thanks for the tips, I'm familiar with them, but I choose the lovely cube because it's the one I would really use out of this three, but I was thinking about http://www.ebay.com/itm/Headphone-Amplifier-kit-Diy-Base-Lehmann-AMP-Circuit-/120764992343?pt=LH_DefaultDomain_0&hash=item1c1e278b57 this one, it looks like an inexpensive firs project for practise soldering.


----------



## francisdemarte

Quote: 





zsubbo said:


> Thanks for the tips, I'm familiar with them, but I choose the lovely cube because it's the one I would really use out of this three, but I was thinking about http://www.ebay.com/itm/Headphone-Amplifier-kit-Diy-Base-Lehmann-AMP-Circuit-/120764992343?pt=LH_DefaultDomain_0&hash=item1c1e278b57 this one, it looks like an inexpensive firs project for practise soldering.


 


  Looks okay, the components are not as nice as the LC but it's certainly inexpensive. I would definately invest in a better volume pot.


----------



## Zsubbo

I tough so too about the volume pot, or maybe I'll just use matched resistors. I should get a transformer like this http://www.ebay.com/itm/220V-115v-30W-R-Core-Transformer-preamp-9V-2-15V-2-/120658545276?pt=BI_Circuit_Breakers_Transformers&hash=item1c17cf4a7c too for the project, and maybe some Hammond case too (but than I'd have to get a nice potentiometer too, to look nicely) - it's getting expensive, with the added extras


----------



## BlaBlaBla

Usually I do not buy opamps from Chinese market. I am not trying to say that there aren't trusted sellers... I just want to say that is better to make deals with USA, Canada or Japan stores because you do not have to buy 10 opamps to get one genuine... I bought 6 opamps from China sellers (AD, Burr Brown) and 4 of them were fakes (2xAD OPA979, BB OPA627 and even cheap OPA2134). Also bought 7 opamps in Canada, UK and USA and all of them were genuine (BB OPA2111, 2xBB OPA2017, BB OPA2132, LME49720HA, 2xLM4562). Off course, price was higher but who cares when you know that IF YOUR OPAMP DIES - YOUR HEADPHONES WILL DIE WITH IT (if opamp goes off - headphones will get 5V DC voltage, and that means death after one second).
   
  So, you should choose your opamp carefully.
   
   
   
  Quote: 





mad max said:


> Let me help you, sir.
> 
> 
> 
> ...


----------



## BlaBlaBla

Quote:


alanbeeb said:


> Ok - thanks for the offer to help - I'll get back shortly with what I find.  I'm using highest gain setting +20db


 

 High gain is more prone to oscillation. So if you change your opamp and use the highest gain in your LC, you should check DC offset on its headphone output. You should check DC offset with volume pot turned on to minimum, and also on to maximum. There is possibility that fast opamps like BB OPA2604, AD xxx, and especially LM xxx might start oscillating. For example AD797 is one of them. So if that happens (I tried that with AD797), your DC offset will raise from 5 mV (when volume pot is 7 o'clock) to even 60 mV (volume pot is 3 o'clock).  
   
  Opamps like OPA627, OPA 2111 and especially OPA2107 are excellent choice because they are slow - and will not oscillate. Well, OPA627 is not so slow, but it can forgive mistakes in circuit topology. AD-s and LM-s will not. For something unique (blazing fast) LC is not good enough. Its topology is limited.
   
  Stock OPA2134 is known as very stable opamp and you can put it everywhere (amplifiers, supplies, etc...) Because it is SLOW. So BCL (and LC) power supply and output (without feedback) are designed for slower opamps (slow if we compare them with those in medical equipment, measuring equipment, radars, sonars, TV-s...). If you trying to put fast opamp in LC without feedback, you should be careful, and always measure voltages on output. And before using expensive headphones - test 4 or 6 hours with cheap/crappy low impedance headphones.


----------



## alanbeeb

currently got pairs of 627, 637, AD797 and OPA602 all sourced from RS components in UK and waiting to roll.... but still waiting for that double adapter from China!


----------



## Monago

deleted.


----------



## alanbeeb

Anyone know a source for the double op-amp adapter?  I've been waiting too long for the one on ebay from china.


----------



## Mad Max

Here's a couple of others that may be good.
  http://www.ebay.com/itm/2x-DIP-DIP-Dual-Mono-Opamp-PCB-Adapter-OPA627BP-/220788700790?pt=LH_DefaultDomain_0&hash=item3368083676
  http://www.ebay.com/itm/2x-DIP-DIP-Dual-Mono-Opamp-PCB-Adapter-OPA128SM-/120757524873?pt=LH_DefaultDomain_0&hash=item1c1db59989
  http://www.ebay.com/itm/2x-Dual-Mono-Opamp-PCB-OPA2604-NE5532-LM358-OPA627-/220828096718?pt=LH_DefaultDomain_0&hash=item336a6158ce  <== I have this one.  Sturdy, well-made adapter that has lasted nearly two years of frequent use so far and still looks new.
   
  You could try contacting this guy, see if he can make any, if you don't want any from China.


----------



## taiyoyuden

I recently bought one second hand from someone on this forum. I noticed the left and right channels are mixed up so I had to plug Red into White, White into Red as a temp. solution. Is there an easy way to fix this?
   
  Edit: What gain setting would be best for k701?


----------



## francisdemarte

Quote: 





taiyoyuden said:


> I recently bought one second hand from someone on this forum. I noticed the left and right channels are mixed up so I had to plug Red into White, White into Red as a temp. solution. Is there an easy way to fix this?
> 
> Edit: What gain setting would be best for k701?


 

  
  You'll have to open up the box and resolder the wires in the correct plug. Really easier if you know how to solder or know someone who does.


----------



## Mad Max

Use gain of 10 for K701.


----------



## Syik

Hello Lovely Cube owners,
   
  Any idea if Lovely Cube would pair well with HD600s? 
   
  Yik


----------



## Mad Max

Yes, it does.


----------



## BlaBlaBla

Quote: 





taiyoyuden said:


> I recently bought one second hand from someone on this forum. I noticed the left and right channels are mixed up so I had to plug Red into White, White into Red as a temp. solution. Is there an easy way to fix this?
> 
> Edit: What gain setting would be best for k701?


 

 Cool!
   
  The best gain for k701 would be to make better cooling first, and then to check DC offset - because stock BC550/560 are crap. Now I know that those PH transistors are not made by Philips and nothing but low cost fakes that like to burn very often.
   
  I would like to se someone who will be able to listen to music more than 4 hours when outside temperature is >30C. _"Do not drill/remove top plate, because it has to keep components warm. They sound better."_ - So big pile of **** I have never seen. Maybe someone likes the sound of barbecue!


----------



## nsk1

Does anyone know how much power Lovely Cube puts out at 600 Ohm?


----------



## BlaBlaBla

Quote: 





nsk1 said:


> Does anyone know how much power Lovely Cube puts out at 600 Ohm?


 


http://www.ebay.com/itm/Matrix-M-stage-Headphone-Amplifier-Amp-LATEST-VERSION-S-/330454610560?pt=LH_DefaultDomain_0&hash=item4cf0a13280#ht_6749wt_952
   
  400mW into 600Ohm


----------



## nsk1

I don't think it's possible. I've read comparisions between LC and Matrix M-Stage and they said that LC is more power efficient, don't know why would it since it's a clone, but I know a couple of people who confirmed it.


----------



## BlaBlaBla

Quote: 





nsk1 said:


> I don't think it's possible. I've read comparisions between LC and Matrix M-Stage and they said that LC is more power efficient, don't know why would it since it's a clone, but I know a couple of people who confirmed it.


 

 LC has stronger transformer (30VA) and more biased BC550/560C transistors. It is 1.2K resistor in LC, instead of 1.5K resistor in Matrix M Stage. (More current is allowed to pass through BC-s.) 
   
  But that has impact only on low impedance headphones. I think, high impedance one will have advantage with higher voltage PSU.


----------



## taiyoyuden

Quote: 





blablabla said:


> Cool!
> 
> The best gain for k701 would be to make better cooling first, and then to check DC offset - because stock BC550/560 are crap. Now I know that those PH transistors are not made by Philips and nothing but low cost fakes that like to burn very often.
> 
> I would like to se someone who will be able to listen to music more than 4 hours when outside temperature is >30C. _"Do not drill/remove top plate, because it has to keep components warm. They sound better."_ - So big pile of **** I have never seen. Maybe someone likes the sound of barbecue!


 
   
  http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/315#post_7236719
   
  Does it have anything to do with this post here^? I want to make the same changes but I have zero experience. If someone can give me some very clear, detailed and hand-holding instructions, I'll go for it! I think I can google for the parts on my own.
   

 Quote:


francisdemarte said:


> You'll have to open up the box and resolder the wires in the correct plug. Really easier if you know how to solder or know someone who does.


 
  Quote: 





mad max said:


> Use gain of 10 for K701.


 
   
  Thanks thanks thanks


----------



## BlaBlaBla

Yes it has. You can replace a few parts, but the crucial is to buy genuine parts available on the market..  Flukell is extremely experienced old school DIY-er but you can't find genuine Philips any more. Also, he mentioned that in the post. Transistors that are supplied in Lovely Cube kit are Philips copy. So when you know that searching for genuine parts is like Don Quijote story, the best that you can do is to buy genuine Fairchild/On Semi/NXP or similar. Do not search for Philips or Toshiba because they do not exist any more (as far as I know - the type that can be implemented in Lovely Cube). Matching transistors (especially BC550/560) will give you great advance in the sound and lower your DC offset. In this case it is better to have matched On Semi transistors than to have non matched NXP.
   
  Next that you can do, is to find better capacitors. Stock Elna are good enough if they are new. That means that 5 years old electrolytic capacitor (from old stock) is worse than a new one. Because electrolytic capacitors are prone to dry out. I think that in Lovely Cube you should try Panasonic FC or Philips BC. Both are excellent. Panasonic FC have deeper sound stage, Philips BC have better dynamic. Do not use Panasonic FM because those capacitors have TOO LOW RESISTANCE and regulators will start to oscillate. They are not recommended after LM317/337 regulators. If you want something more audiophile you can try Elna Cerafine or Tonerex. Elna Silmic won't fit into Lovely Cube because it is too big. But be aware because Lovely Cube goes very hot and Elna won't last too long.
   
  Also, you can replace (in LM317/337 circuit) resistor 1.2K with zener diode (13V, 1.3W). On some sites I heard that this can reduce noises from regulators. I did that and it is ok. But when you do that, be shure to put two zener diodes (parallel) because of safety reasons.  You can play with ADJ and OUT capacitors on LM 317/337 circuit and find capacity that suits you the best. Personally, I found that tantalum alone (by the book for LM regulators) as ADJ capacitors give the best punch and response. Be aware that tantalum capacitors must have voltage twice as much than voltage across them.
   
  Good resistors are not important if there are only a few in a circuit. But if you change resistors on lots of places then you will see improvement. Here I think on cheap but good resistors like PRP, Holco, Kiwame or Vishay Dale (which is one step below first two and represents industrial long life resistor). Using high class (Takman, Shinkoh, AMRG etc...) is total nonsense because circuit alone is not capable to give enough to make those resistors worth. I tried cheap Riken OHM (carbon film) as output resistors (10 Ohm, 2W) and found out that they are excellent. Allen Bradley is excellent too, if you can find them cheap. They have clarity and sound is more relaxed (not too aggressive). In signal path I always use metal film because I don't want any coloration in the sound.
   
  Quote: 





taiyoyuden said:


> http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/315#post_7236719
> 
> Does it have anything to do with this post here^? I want to make the same changes but I have zero experience. If someone can give me some very clear, detailed and hand-holding instructions, I'll go for it! I think I can google for the parts on my own.
> 
> ...


----------



## alanbeeb

Quote: 





nsk1 said:


> Does anyone know how much power Lovely Cube puts out at 600 Ohm?


 

 And anyone know how much power it puts into 50 ohms?
  I finally received the double opamp adapter a couple of weeks ago and have not really heard too much difference between 627,637 and others.  
  However am now driving a pair of Hifiman HE-6 from it.... and it seems to have enough power for the job, but quite dark sounding, not too bright treble at all.


----------



## BlaBlaBla

Maybe you should try OPA2111 (v shape - bright high, hard middle high, weaker middle low and good low) or OPA2604 (mellow high, excellent middle, weak low). They are opposite to OPA2107 and OPA627...

  
  Quote: 





alanbeeb said:


> And anyone know how much power it puts into 50 ohms?
> I finally received the double opamp adapter a couple of weeks ago and have not really heard too much difference between 627,637 and others.
> However am now driving a pair of Hifiman HE-6 from it.... and it seems to have enough power for the job, but quite dark sounding, not too bright treble at all.


----------



## chetlanin

The lazy way to correct for voltage offset independently in L or R channel.(there are other ways, of course!)
   
  (In my case the offset was rather high in one channel, 17mV, while very acceptable in the other. A little trying and failing, and I ended up with less than 1mV offset by reducing the resistance in (what I call) R3 in the drawing to ca. 1.4k by  (from 1.5k) by adding an Rx=18k in parallel. The Idle current was accordingly increased by less than 2mA (of 57mA originally), a totally insignificant change IMO. I don't know if this could be of interest to any of you. You can see the added resistor in the photo).
   
  I must not forget to say thanks to all for an interesting thread, Olaf
   
  (this is also a kind of test posting, since it is my first)
  .


----------



## BlaBlaBla

You could use trimpot (50K or 20K).
  
  Quote: 





chetlanin said:


> The lazy way to correct for voltage offset independently in L or R channel.(there are other ways, of course!)
> 
> (In my case the offset was rather high in one channel, 17mV, while very acceptable in the other. A little trying and failing, and I ended up with less than 1mV offset by reducing the resistance in (what I call) R3 in the drawing to ca. 1.4k by  (from 1.5k) by adding an Rx=18k in parallel. The Idle current was accordingly increased by less than 2mA (of 57mA originally), a totally insignificant change IMO. I don't know if this could be of interest to any of you. You can see the added resistor in the photo).
> 
> ...


----------



## chetlanin

Quote: 





blablabla said:


> You could use trimpot (50K or 20K).


 

 I think you are right, esp in principle (so to speak): It would make it much easier to find the right setting. Personally i think that a resistor has advantages in this case, however. I will be easier to solder on, after that legs have been bended and cut to a suiteable form. Also it is less bulky, cheaper, more often at hand I suppose, and (in principle) more stable...

 (I made only three attempts with higher values, by holding a resistor against the legs of "R3" on the component side of the board , before I landed on the right value. But one needs a steady hand for that, true).

 The main point was -in any case-  that this was a convenient place in the cirquit to make such an individual adjustment, since you don't need to de-solder any component (or come close to the rather tiny solder joints by the BC transistors and surrounding resistors. Cheers, Olaf


----------



## miky2011

I received the kit of the "Lovely". I am making a request to replace some components with others with higher confidence.
   
  My main concern is in the transfomer. In this post http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/390#post_7247740 the user Flukell  claims that with more (VA) the sound is greatly improved.
   
  The original "Lehmann" features a 30VA transformer?
  It is true that, for example, a 60VA transformer will improve the sound compared to 30VA Talema of the seller? Why?
   
  Sorry for my english.


----------



## BlaBlaBla

You should try transformer with EI core (if you can find one very cheap) because toroidal transformers are very sensitive to noise in the power grid. Also they tend to pass through high frequency noise that are sometimes in power grid, and saturate very fast. EI core transformers are not prone to noises from grid and with them in a circuit you do not need capacitors over recitfier. Furthermore you do not need ultra fast rectifier at all because high noises will not pass through.
   
  If you are able to separate transformer from rest of the circuit or you can make faradays cage for transformer, you should pick up as big transformer as you can put into your case. 60VA > will be enough. When you want to choose transformer, always have on your mind that real power is 80% of its max power. In the case for the 60VA transformer, it would have 40-50W real power (and sometime less). Because this is stereo and push pull topology it will give you 25VA per channel (1,5 A). This is not important when you want to drive high impedance headphones, but for low one - it is.
   
  Originally Posted by *miky2011* /img/forum/go_quote.gif


> I received the kit of the "Lovely". I am making a request to replace some components with others with higher confidence.
> 
> My main concern is in the transfomer. In this post http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/390#post_7247740 the user Flukell  claims that with more (VA) the sound is greatly improved.
> 
> ...


----------



## nsk1

Interesting. What about R-Core BlaBla?


----------



## BlaBlaBla

Excellent choice, but hard to get a good one with good crafted core and windings. Personally, I think that difference is not as much as price is. Because we talk about power transformers, you actually need a transformer that primary goal is to suppress noises from power grid, and have enough power (current). Superior transformers (like toroidal - better efficiency, less weight, less magnetic field, etc. etc) are better in most departments - especially magnetic field and efficiency, but the last in suppressing noises. They pass through entire spectrum (garbage from grid). EI transformers don't. Actually, if you can isolate magnetic field of EI core, you do not need toroidal transformer at all. But if you want to save space in your enclosure (metal box) then toroidal is way to go.
   
  Keep in mind, if you use toroidal transformer, you will have to use fery fast diodes in rectifier, and capacitors over diodes. Input caps must not be too big because toroidal transformer has huge starting current so with too big capacitor current will be even bigger - and fuse will blow. This is case when 200 VA > transformer is used...
   
  When you use EI core, noises will be lower frequency but not from grid, but from transformer itself. Very good EI transformers have very low hum that is easy to handle and suppress, but they always have low hum. Some people do not want that, some do not care. I do not care too much, because it is audibile when you trying to listen to silence and not music. Also you can use bigger input capacitors because cold start current is much lower. EI transformers do not need ultra fast diodes in rectifier because less garbage passes through (high frequency). With slow diodes you do not have problems with noises made from rectifier itself. Fast recitfiers do not have any sense when they are used for 50/60 HZ frequency.
   
  Quote: 





nsk1 said:


> Interesting. What about R-Core BlaBla?


----------



## chetlanin

Quote: 





miky2011 said:


> I received the kit of the "Lovely". I am making a request to replace some components with others with higher confidence.
> 
> My main concern is in the transfomer. In this post http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/390#post_7247740 the user Flukell  claims that with more (VA) the sound is greatly improved.
> 
> ...


----------



## miky2011

Great thread !!! Thanks for your answers ...
   
    I bought the "LovelyCube" for the fun of being able a "exact" copy of Lehmann BCL. That's my goal. 
	

	
	
		
		

		
			




   
    That is the reason why I like to know what type of components is mounted in the Lehmann Original. Some are named along the wire. It would be useful put them together in one post.
    It may be interesting that we all make a list. There are not many components and can be very useful for those who want to change this or that component.
   
    For example, I would like to know what type of resistance used in the original Lehmann (tolerance, VA, brand, etc ...). what kind of resistance are 10R (four) in output? 
    
    About transformer. In the previous post Chetlanin say that is more than enough with 30VA. Flukell http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/390#post_7247740  claims that with more (VA) the sound is GREATLY improved. 
   
    its true? not its true? can anyone clarify this?
    more "¿unnnecesary?" power = better sound    why??????
   
  Sorry again for my english.


----------



## chetlanin

Difficult to go further about the transformer, miky. Personally I do not believe that it is the way to go to improve the amp, as I said.
   
  Listen, why copy the Lehmann? Funny idea, but you can make this amp much, much better than the Lehmann by concentrating on a few important things, the weak spots so to speak, rather than changing resistor types and capacitors which are highly unlikely to make any significant difference. First: You can simply put in a better op-amp, and it is highly likely that you already have surpassed the Lehmann, sonically speaking. Second: You must concentrate on the the non-linear components, and that means the transistors. The Chinese stuff (and the recently made Western stuff in general) is not considered the best. Find the best of the older types you can (for example old stock Philips or Siemens made in Europe in the second half of the last century). If necessary pull it from old equipment. Match the transistors in pairs before soldering it into the amp. That is all, in my opinion. No wait, I would add a couple of minor mods which to me has some meaning: Find the right setting of the sensitivity switch and solder the resistor(s) in place. In addition -and here I am w Lehmann - solder the chosen opamp into the board. Really secure connections are of great importance, esp in the long run. Olaf


----------



## BlaBlaBla

Improvement you can achieve in two ways. In most cases cooling is of great importance, second is the power supply. On both companies trying to save money. If you want to make something unique, you should try to make LC on your own. Lovely Cube is simple and effective amplifier. Start with power supply. First that might improve things is to separate power supply for transistors and for opamp. Opamp is very sensitive part and demands the best psu that you can built. Also opamp does not like to share power with other fast devices (transistors, oscillators etc...) Second, power stage might be better if channels are separated, which means, capacitors for left and for right channels could be independent, regulators also. There is enormous things that can downgrade or improve results. Zener diode instead R2 resistors? Why not. It work perfectly for LMs. Double bridge rectifier? Why not. They are very cheap. If you don't try you won't know.
   
  Right now I am building something like that. My philosophy is not to search for the best amplifier or project arround and work on it next four years- But pull out the best from simple topology (schematic) that I currently own, and that can be easily built.
   
  If you are buying new transformer, buy a big one. One day you might fintd it useful in another amplifier/DAC/DIY project. Transformers can last forever if you do not kick them around or smash them with hammer.
   
  30VA is not 30W. This depends on your load. It can be 25W but also 15W. If we look for the worst scenario then 15W is 7W/channel or 0.5A/channel... Bigger transformer will have more energy in reserve. Especially during cold start, or when driving your equipment on limit. It is not the same if your transformer has lower value arround 15W (30VA) or arround 30W (60VA).
   
  Lots of people say that if you need 10VA  for B class amplifier, for pure A class you need 3x more. (A/B class is arround 2x). The same goes for cooling and heatsinks. 
   
   
  Quote: 





miky2011 said:


> Great thread !!! Thanks for your answers ...
> 
> I bought the "LovelyCube" for the fun of being able a "exact" copy of Lehmann BCL. That's my goal.
> 
> ...


----------



## chetlanin

I agree with blablabla (and others) when it comes to the need for good cooling. I would never put this into an unventilated box (madness!).
  At this point I have chosen the easy way out, and reduced the idle current by replacing the 1.2k resistor in the output section with 1.5k (reducing the idle current from ca 57mA to 41. At the same time I replaced the original BD's with some well-matched Fairchild BD's i had laying about,  so I can't say which of these mods has influenced it the most, but the amp sounds at least as nice as it did before, and runs cooler. (I still would use a vented box, though).


----------



## miky2011

Ok,
   
       I followed the thread from beginning to end.
   
      I have some doubts about some components:
   
      a) The four output resistors 10R/1W 1%. Is it better to be "Metal Film Resistors" or "Wirewound Resistors"? . I have both (Vishay) types and I have no idea what to ride.
   
      b) The four 0.1uF capacitors. ¿250V.? . In the list of components of the "Lovely Cube" indicates 250V. but the PCB is shown in the images that mounted 400V. (also in the original BCL?) Is it possible to mount 250V/0.1uF capacitors. no problem? Is it required to be 400V.? At home i have EPCOS Polyester Film 0.1uF/250v 5%. (smaller in size that 400v. capacitors)
   
      c) The two capacitors 100pF/63V. associated with the OPAMP. At home I have this Kemet 100pF/63V/5% http://www.kemet.com/kemet/web/homepage/kechome.nsf/vapubfiles/F3294_PFR.pdf/$file/F3294_PFR.pdf
  But in the original BCL and Lovely, I think, mounted this type http://www.farnell.com/datasheets/28681.pdf
  Are there differences between both? Both are Polypropylene. But they are different format (cylindrical vs capsule).
   
      d) The four capacitors 0.022 (22nF) / 63V. I have at home EPCOS Polyester Film 22nF/100v. 5%. They have different format. In the Lehmann and "Lovely" they are cylindricals  and EPCOS are capsule format. Better or Worse that the original capacitors in "LovelyCube"??.
   
  These are my doubts ... I hope your opinions .... A greeting.


----------



## francisdemarte

b) Which image is this? I don't think that any component on the LC would require a 400v rating.


----------



## miky2011

For example, this image. Make zoom. You will see 400v.
http://www.alicemagicbox.com/image/lovelycubenichicon01.jpg


----------



## BlaBlaBla

a) It depends where you want to put those resistors. Wirewound resistors are the best when you must isolate something. For example, opamp is isolated with 47ohm wirewound resistors (green one) from the rest of the circuit in Lovely Cube. That is made because wirewound resistors does not have (or make) parasitic noise. But they have big inductance. Bigger than any other type of resistor. When you want to put resistor in highly precise circuit with fast response, wirewound resistor is the least that you would choose. Metal film is way to go. But there is a lot of metal film resistors. Some of them are less inductive like PRP, Holco, Shinkoh, and some of them are more inductive like cheap no name brands made in the backyard.
   
  b) There are two the most common places where capacitors are used: like energy tanks and like a part of filter. Capacitors as energy tank with bigger nominal voltage have always better dielectric isolation because they are bigger. And last longer because they are bigger - better heat dissipation. That means if you have two capacitors with same technical spec (voltage and capacity) the bigger one would last longer and have better sound characteristic. Capacitor as a part of filter has the same advantage than smaller one and is able to handle bigger signal amplitude. For example, MKP 0.1uF,  63VAC would handle 2V peak to peak on 20 kHz, but MKP 0.1uF,  250VAC would handle 6V peak to peak on 20 kHz. Also 4.7 uF, 250VAC would handle 3V peak to peak on 20 kHz which means that bigger capacitor with high voltage would handle less than smaller capacitor with the same rated voltage. So, you have to check charts and see if your 0.1uF, 250VDC is able to handle voltage that is within your requirements and within audible range (20 kHz is max). In this case it is important to make compromise because you do not need nothing above 20 Khz and x volts. So if  0.1uF, 63V capacitor satisfies both requirements you can put it in. 250V is better but you will not see improvements.
   
  c) In signal path there are two crucial capacitors - input (big blue) and this one. Big blue does not allow DC signal to pass further and this one does not allow high frequency to pass through opamp. Here you have to place the best (and fastest) capacitor that you have. This capacitor blocks non audible frequency (above 30 kHz) to pass through opamp because of two reasons. First is noise in output signal and second is possibility that transistors might start to oscillate. In this case - MKP (for higher temperature, average linearity, good filtration) or Polystyrene (lower temperature but best linearity and the best filtration).
   
  d) The shape of capacitor is not important if you know technical specification. Usually old cylindrical capacitors (like ERO) have bigger inductance than the new (block/capsule) one. It depends when you want to put them. If you put them into signal path you might notice that sound is less aggressive and "slower". Sometimes this is good characteristic because you need something like that to achieve better synergy with other components. A lots of people mix two type of capacitors in a parallel connection - old and huge ERO (>10 uF) and small polystyrene (30nF). If you put them into power supply it might be good because some supplies does not like ultra fast capacitors with high response (peaks and high frequency oscillations). Also, capacitors have characteristic that depends on temperature. It is different if you put MKP instead of MKC in place where high temperature is expected. In warm places (90C) MKC would be better than MKP (that would start to melt down) and Polystyrene (that would burn out completely). In cold places (25-40C) Polystyrene would be miles ahead from MKC nad MKP. (It will kick their butts.)
   
   
  Quote: 





miky2011 said:


> Ok,
> 
> I followed the thread from beginning to end.
> 
> ...


----------



## miky2011

Blablabla, beautiful answer and very useful for me. Thanks.
   
  a) I think "Lovely Cube" use 10R/1W *Wirebound Resistors* and "Original BCL" use *Metal Films Resistors*. Its that true?
   
  b) This green capacitors are 0.1uF/400V. in the Lovely Cube http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone.
      I think, by the size, wich are 400v. in the original BCL too. Do you think too much 400V.???? I have EPCOS 0.1uF/250V. at home... Do you ride to the PCB "Lovely Stock 400v. capacitors" or my originals EPCOS 250V? Do you think that affect something in the sound profile?
   
  c)  I decided to use the stock 100pF capacitors included with "Lovely Kit". Bad idea? .  I dont found in electronics stores of my country this component in its original BCL format.
   
  d)  I find its curious that in this picture the capacitors 22nF have different format. http://blogs.yahoo.co.jp/ponsan3211/16229403.html . Now are "capsule format". 
	

	
	
		
		

		
		
	


	



   
   
  Regards.


----------



## chetlanin

You must be careful with those output resistors, the right value is 10 Ohm!
   
  10R not 1R, as you have written repeatedly.
   
   
  Personally I think that you can use any type resistor,  and they will all sound the same.
   
  In principle bifilar wirewound types are best, I believe  (they are wound in a way to reduce induction to an insignificant level)
   
  Cheers, Olaf


----------



## miky2011

Fixed bug.... are 10R...
   
   
  Wirebound best that Metal Film? ..... OK ....


----------



## miky2011

I think to use panasonic FM capacitors 470uF/35v. (Very low impedance)

There are good capacitors for that?.


----------



## miky2011

A greeting to everyone. 
   
  I just received the Kit of Lovely Cube this afternoon.
   
  I have welded all components. The problem is that the sound its very low even to max. volume. I use 150ohm. headphones and the volume its same as directly connected to Ipod.
   
       All three leds ON. BDs139 and BDs140 are hot (i think that's right). 
   
       I have reviewed the PCB and all components are in place.  What can happen? Can you give me any clues?
   
   
  Regards. I hope your aswers. I'm pretty frustrated with it.


----------



## francisdemarte

Hard to say without seeing the board. Can you post some pictures? What source are you using? What are your gain settings on the DIP switches? 
   
  Other things to check just off the top of my head:
   

 opamp is seated properly and in the correct direction
 double check for solder bridges between the components


----------



## miky2011

Hi francisdemarte,

Tomorrow i will can show someter picture

My source: Sansa clip+ 
Gain: 0db

Its a must make the solder on two sides of PCB?

I make the solder only in one side (upside resistors and downside rest of componentes).
Thats right or is an error?


----------



## francisdemarte

Gain: 0db  <--- There is your problem! You are not amplifying anything! Set this to something higher, I say start with 10db or 18db. Set BOTH sets of switches to the same setting. 
   

   
   
   
  That is correct you only need to solder the bottom part of the board.


----------



## Tribbs

Regarding the gain setting of the DIP switches:
   
  If the above photo accurately depicts the settings.
  White should designate the toggle and black should be interpreted as the void.
   
  And, they are binary!  <D'oh!>
   
    0 dB = Down|Down = Off|Off = "00" binary = "zero" decimal
  10 dB =     Up|Down = On|Off = "10" binary = "two" decimal
  18 dB = Down|Up     = Off|On = "01" binary = "one" decimal
  20 dB =     Up|Up     = On|On = "11" binary = "three" decimal
    *[size=medium]=[/size]* Down | Down = Off | Off = 0 dB


----------



## miky2011

Hi Francisdemarte,

0db = lovely cube only pass the sound without amplification?

Its that true?

I have doubts about that ...


----------



## francisdemarte

Gain by definition is "an increase in"
   
  Technical definition of gain:
   
http://whatis.techtarget.com/definition/0,,sid9_gci499581,00.html
   
   
  The amplification factor, also called _gain_ , is the extent to which an [size=10pt]analog[/size][size=10pt]amplifier[/size] boosts the strength of a [size=10pt]signal[/size] . Amplification factors are usually expressed in terms of [size=10pt]power[/size] .
   
  The [size=10pt]decibel[/size] (dB), a [size=10pt]logarithmic[/size] unit, is the most common way of quantifying the gain of an amplifier. For power, doubling the signal strength (an output-to-input power ratio of 2:1) translates into a gain of 3 dB; a tenfold increase in power (output-to-input ratio of 10:1) equals a gain of 10 dB; a hundredfold increase in power (output-to-input ratio of 100:1) represents 20 dB gain. If the output power is less than the input power, the amplification factor in decibels is negative. If the output-to-input signal power ratio is 1:1, then the amplification factor is 0 dB


----------



## miky2011

I still have the problem.
   
  With the gain at 0db. I have not amplification. I have to put the volume to maximum to hear the same volume as I listen to my Sansa Clip + directly. Even a little less with "lovely". 
   
  With the gain to 10, 18 and 20dB I have changes in the output sound. I have SOME LITTLE amplification but I have yet to set the volume to maximum to have enough volume to hear worthily.
   
  I have to say that I don't have hearing problems. ! My Lovely does not amplify the input signal !!!
   
  Attached photos of my PCB front and bottom.
   
https://www.dropbox.com/gallery/2747771/1/Lovely?h=53f1a2
   
   
  * Will note that I've made ​changes of components for originals equivalents. All changes with same capacity in the case of capacitors and the same resistance in the case of resistors ( I've only changed the value of the four 1K2 resistances by 1K5).
   
  * I changed the LM317 and LM337 by originals 337T and 317T with bigger heatsinks.
  * I changed BD139 and BD140 by BD139-16S and BD140-16S.
  * I changed BC550 and BC560 by BC550CG and BC560CG.
  * Input bigger capacitors have different format but are same capacity and voltage that stock lovely clone. Smaller input capacitors are MKP 22nF/1000V. (i had tested with originals and i had the same problem).
  * 22nF opamp capacitors are KP1837.
  * 100pF opamp capacitors are LCR FSC (100pF/160V./2,5%)
  * Opamp is original 2134 . With 2134 and 2111AM lovely stock i have the same problem.
   
   
  I'm pretty worried. I do not understand what is happening. Any suggestions.???


----------



## Tribbs

Miky,
   
  Did you try another source other then your Sansa Clip?


----------



## francisdemarte

Take your time and go over and reflow all your solder joints. Including the ones to your RCA sockets.
   
  Make sure the components you replaced are solder in the right way. Especially the regulators, the 3 legs, Vin Vout and G are in the right way
   
  Your Fuze should be set to max volume. 
   
  Set that gain to something above 0. I suggest 10 or 18 since it's easier to notice 1 up and 1 down switch.

 Use the stock opamp.
   
  Do you have a digital multi-meter? You might need to make sure the voltages are correct. I'm not sure where all the test points are try emailing stephen for some tips, and/or PM BlaBlaBla.


----------



## miky2011

Hello,
        here I am with my problem.
        I have reviewed all solders. I have tested dip switches for gain function properly off and on.
        All components are in place. I have measured voltages with digital multimeter:
   
       - BD140 BD139:              collector-base .- 14v.
                                             collector-emitter .- 14v.
                                             base-emitter .- 0.6v.
   
   
       - BC550C BC560C:         collector-base .- 15v.
                                            base-emitter .- 0.6v.
   
       - LM317T LM337T :          Adj .- 13.8 v.
                                             Input .- 21.6 v.
                                            Output .- 15.0 v. (-15.0 for LM337T)
   
       - OPAMP 2134 is receiving 14.7 v. 
   
      I have replaced the opamp with the stock. I have changed the sound source by putting my phone even the maximum volume.
      Despite all this I still have to put the volume to maximum to hear the music. Even on 20db. gain !!.
      With 0dB. even I noticed that the sound is attenuated.
      
      HELP !!


----------



## francisdemarte

Sorry for  your troubles, I know your pain, the it took me a month to get my first DIY DAC working correctly.
   
  You've hit my limit on technical expertise. Try posting to the DIY forum or email the seller at seaipoju@yahoo.com.
   
  Another quick test is to make sure the cable you are using between your Fuze and amp is good.
   
  Have you tried another source, like a cd or dvd player something with more output voltage than your Fuze.
   
  Is there a way you can check if the opamps have been damaged?
   
  Maybe your volume control may be defective. Unforunately, the only way I know of testing one is to remove it from the board test the resistances when you turn it.


----------



## francisdemarte

PS also try the matrix m stage thread.


----------



## BlackstoneJD

Does the Lovely Cube Premium even hold a candle to the original Lehmann? Has anyone done an actual sonic comparison?


----------



## francisdemarte

BlackstoneJD:
   
  Very few people have heard both, the few impressions that I've read they indicated that they do sound different. It's impossible to judge audio equipment by someone's opinion over the internet. You have to judge for yourself.
   
  Are you in Chicago? There is a head fi meet coming up in a few weeks in Northbrook. I went to one last year, my first ever, and there is a lot of amazing equipment to try out. Details here: http://www.head-fi.org/t/574527/chiunifi-5-the-official-and-annual-chicago-area-headphone-get-together-november-12th-2011 Unless my wife schedule me for something else, I'll probably show up this year too.
   
  If you want PM me and I'll lend you my cheap plastic box build of the Lovely Cube so  you can get an idea of what it sounds like.


----------



## Tribbs

You started this thread Matrix Vs Lehmann 18 months ago.
   
  Also check out the arguments here: [size=x-small]http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures[/size]
   
  [size=10pt]If you are seeking a comparison in your consideration of purchasing a Lehmann BCL why not buy both, make the comparison yourself and sell one?[/size]
   
  [size=10pt]Personally I'd rather spend my cash on another set of cans.  [size=10pt]I just can't justify what, if any, added value the price of the BCL brings over a Matrix/Lovely clone.[/size][/size]


----------



## francisdemarte

Here is probably the best comparison post I've seen between the Lehmann and the Lovely Cube:
   
http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures#post_7364890


----------



## Maverickmonk

Looking at assembling a Lovely cube to mod and play around with, but I was wondering: If I wanted to be able to use it as a pre-amp, would I just reroute the leads to one of the headphone jacks to RCA's on the back panel (twisted and shielded, maybe coaxial pairs)? If so, which jack should I use for the preamp? (I read that one is line out-muted and the other is line-out?).  Also, would it be adventagous to create a simple grounded-shield to cover the transformer?


----------



## chetlanin

How are things, miky?
   
   If the good advices from francisdemarte has not brought a solution, I think it might be an idea to check if the signal is present at the output of the opamp. You could use at 1k sinus wave at the input (and turn up the volume a bit). A multimeter should show the AC signal at the points shown in the picture (which are directly connected to the output pins of the opamp). You should easily be able to get lots of Volt out of the chip.
   
  For that matter you send music into it and take the signal from here,  and (together with a ground lead) connect to a pre-amp input).
  Preferably connect through a 100-1000 Ohm resistor close to the output, in this case).
   
  I strongly suspect that something is wrong with the op amp or its connections.
   
  A pair of completely wrong resistor values is theoretically also a possibility, in a case like this.
   
   
   

  
   
  P.S.
  In principle this should be a very easy case! The fault showing in both channels, so it must be something very fundamental or simple, and one will always get to the root of it with a few checks or measurements. (more difficult are often faults which are appearing sporadically).


----------



## francisdemarte

Quote: 





maverickmonk said:


> Looking at assembling a Lovely cube to mod and play around with, but I was wondering: If I wanted to be able to use it as a pre-amp, would I just reroute the leads to one of the headphone jacks to RCA's on the back panel (twisted and shielded, maybe coaxial pairs)? If so, which jack should I use for the preamp? (I read that one is line out-muted and the other is line-out?).  Also, would it be adventagous to create a simple grounded-shield to cover the transformer?


 

 Since your using it as a pre-amp I don't think it will matter.
  I would use the jack furthest away from the volume knob if you want to keep the mute function of the LC pre amp out. Basic behavior is if you plug your phones into the jack furthest way from the volume it will mute the LC's pre-amp out.
   
  Check out this photo of the underside of the board.
   

   
  You can see the Alps pot mounting little holes on the lower left hand side, then 2 pairs of 8 large holes for the 2 - 1/4'' jacks. the traces on the far right lead up to the pre-amp out.
   
  Populated top view of the board for reference:
   

   
  Hope this helps.


----------



## BlaBlaBla

He tried a lot of things. I was also thinking about wrong connections but what I have seen from pictures everything seems OK. Only part that can be wrong is (maybe) volume potentiometer. Because it is logarithmic.

 For comparison I soldered my own Lovely Cube. I did  few minor changes in the power supply and near BD transistors. I made three channel supply (separated channels) for output and opamp. I wanted to know what will happen. I put 1200uFon each output. Elna Silmic II in opamp power supply. Some old ERO 1841 (bypassed with russian polystyrene capacitors) on input. Polystyrene for opamp coupling. Etc, etc... A lot of capacitors in power supply.
   
  Maybe it is silly but it sounds good. On Grado SR225 this funny hand made amp kicks ass. Bass is deep. Very very deep. Highs are mellow but enough fast. Mids are in front. Sound stage is wider and deeper than on Lovely Cube. If I compare the same OPA2604 in Lovely Cube, difference is like heaven and earth. Lovely Cube is maybe faster but also more sterile. This is more old fashion with grunt and deep power. I must admit that I do not like when people listen to oscilloscope and talking about how good is 96 Khz signal in their amplifier. I give a **** about measuring and about 96 kHz when I am able to hear only 18kHz. My ears are the best oscilloscope and they have final word.
   
  Also what I noticed is that this amp does not get warm with stock 1.2K resistors. After turning off there is no DC over voltage on output, and without opamp, DC offset is 0. In Lovely Cube, without opamp, DC offset was 6 volts (SIX VOLTS). So you can imagine what will happen in Lovely Cube if your opamp suddenly stops to work... Here this is not the case. Also this amp has more power because it doesn't sag on very demanding parts in classical music. Bass is always here, mids are always here and highs are always here, no matter what. Drives like a tank.
   
  There is no noise, what is really interesting, because of lots of wires and connections. I tried to implement multiple layer grounding (separate grounds for signal, opamp and supply but that did not work. Too much noise. When I had done star ground (below PCB, close to capacitors and rectifiers) noise was gone completely. 5W resistors are on borad because I didn't want to pull them out, but they are not in function.
   

   

   

   

   
   
  It is not on the picture but I put a mute switch in front, that allows me to disconnect headphones without making a short circuit on BD-s. Also, for safety measures I always leave amplifier for 3-5 minutes to work without headphones (mute on)... This is still hand made amplifier. Who knows what might happen. %) If nothing goes on fire I start to listen to music.  I put another transformer for driving OPA2604 (10VA). It is not on the picture. It is added later.
   
  Now I have plans to make another amplifier but with more changes and with less wasted space. I think that after this I would never buy an amp from manufacturer or seller. Because of three reasons: First I like to DIY, second I do not have money for buying something that is made for 300 USD and costs 1300 USD, and finally the third reason - I listen to MP3 mostly and benefit from 4000 USD amplifier, is completely gone right from start.
   
  And fourth reason - I am sick when I see overheated amplifiers with tiny transformers.. Put that amplifier in big box, give it big transformer, and see how it sings...
   
  Quote: 





chetlanin said:


> How are things, miky?
> 
> If the good advices from francisdemarte has not brought a solution, I think it might be an idea to check if the signal is present at the output of the opamp. You could use at 1k sinus wave at the input (and turn up the volume a bit). A multimeter should show the AC signal at the points shown in the picture (which are directly connected to the output pins of the opamp). You should easily be able to get lots of Volt out of the chip.
> 
> ...


----------



## chetlanin

Another comment to the miky2011 case:
  To ensure good grounding the ring with solder tag ’A’ should be on the other side (inside) of the white plastic isolator. It seem to me from the photo that the only grounding you will get here (esp with a coated surface of the cabinet wall) would be a rather insecure contact of the ring with the outer surface of the screw part of the RCA connector. Olaf


----------



## francisdemarte

Hopefully Milky finds the issue with his amp and gets it up and running.
   
  Hey BlaBlaBla, you should start selling your own Ultra-Lovely-Cube with all your modifications!


----------



## Maverickmonk

Doh! didn't even see that it had a dedicated preamp-output pad. This is post-fader right? so the potentiometer can adjust the output?
  Quote: 





francisdemarte said:


> Since your using it as a pre-amp I don't think it will matter.
> I would use the jack furthest away from the volume knob if you want to keep the mute function of the LC pre amp out. Basic behavior is if you plug your phones into the jack furthest way from the volume it will mute the LC's pre-amp out.


----------



## francisdemarte

I actually do not have mine connected but according to Lehmann's website both outputs are post fader.


----------



## miky2011

Hello,
   
       I checked all the components in place and value. I think that all is right in this sense.
   
       The only thing that I dont have tested is Pot ALPS.  What is the easiest way to check it? It´s necessary remove from PCB?
   
       I want to thank to everyone the valuable assistance you are given me. Specially to Blablabla. Thanks !!
   
       Its true. The lack of amplification occurs in the two channels equally. The problem can not be so hard.
   
      With 10db, 18db and 20db,  ampliffication occurs but not nearly the amplification that should be right.
   
      Is desperate. I put the photos.
   
    https://www.dropbox.com/gallery/2747771/1/Lovely?h=53f1a2
   
  regards.... i hope your opinions.


----------



## chetlanin

Quote: 





miky2011 said:


> Hello,
> 
> I checked all the components in place and value. I think that all is right in this sense.
> 
> ...


 



 You can measure the Alps, without taking it out, Turn off the power, remove the op amp and also the input cables. Turn the volume knob to its maximum position. The resistance should now measure zero between in and out pins (they are shorted). Turn it all the way down and it will measure 50k (or whatever the nominal value is). Notice that when turning it gradually down from the max volume position, there will be little change of resistance towards the end, because of its logarithmic nature ).
   
  Good to see that you have fixed the grounding at the input.
   
  The main problem is in the op-amp, I still believe.
   
  Olaf


----------



## miky2011

Thanks for your posts.
        
      Chetlanin, you say that the main problem maybe is in the op-amp.
      But ....Where is the problem? All components are in place. I have reflow the solders... resistors and capacitors are in right values.
   
      What I can see in the PCB?
      What I can measure?


----------



## francisdemarte

I'm going to have to agree with chetlanin. I suspect it's either the op-amps or something near that area. Maybe the op-amps are could be damaged?
   
  Milky do you have any way of verifying the op-amps you have are working? Maybe you can wire up a quick op-amp tester: http://tangentsoft.net/elec/opamp-tester.html


----------



## miky2011

Hi francisdemarte,
   
      I tried with three differents op-amps : stock lovely 2134, stock lovely 2111AM and an original 2134 (wich appears in the photos) with the same result and same poor amplification.


----------



## Maverickmonk

Not to derail, but thanks for the idea on the op amp tester! I think I'll build one, it looks pretty useful
  
  Quote: 





francisdemarte said:


> I'm going to have to agree with chetlanin. I suspect it's either the op-amps or something near that area. Maybe the op-amps are could be damaged?
> 
> Milky do you have any way of verifying the op-amps you have are working? Maybe you can wire up a quick op-amp tester: http://tangentsoft.net/elec/opamp-tester.html


----------



## BlaBlaBla

That is interesting... I tried lots of opamps and difference is minor. Maybe OPA 2604 and OPA 627 have the biggest amplification (2-5% bigger). This is probably because different sound stage (OPA2604 and OPA 627 have strong mids). All others are the same. I haven't seen any difference. I always buy opamps from two trusted sellers (USA).
   
  Sellers:
   
  http://www.ebay.com/itm/Burr-Brown-OPA2134-dual-soundplus-audio-op-amp-ic-dip-/260742563447?pt=LH_DefaultDomain_0&hash=item3cb577c677
   
  http://www.ebay.com/itm/Burr-Brown-OPA2107-precision-dual-difet-op-amp-ic-dip-/260655044299?pt=LH_DefaultDomain_0&hash=item3cb04056cb
   
  http://www.ebay.com/itm/Burr-Brown-OPA2604-fet-input-low-distortion-op-amp-ic-/260742565803?pt=LH_DefaultDomain_0&hash=item3cb577cfab
   
  http://www.ebay.com/itm/OPA2111-KP-dual-Low-Noise-DiFET-OpAmp-Pro-audio-1-/180658456056?pt=LH_DefaultDomain_0&hash=item2a101545f8
   
  http://www.ebay.com/itm/OPA2132-PA-FET-Input-Dual-Op-Amp-High-Speed-OpAmp-x2-/170712816483?pt=LH_DefaultDomain_0&hash=item27bf46db63
   
  Something is wrong with PCB. Or opamps are fake...  I do not want to be rude and do not want to offense anyone, but I am always trying not to buy from sellers who are not in Japan, USA, Canada, New Zeland, Europe. I bought two pairs of headphones. One directly from Japan and one from seller in China. Headphones "almost" look the same (difference in language) but they don't sound the same. *Lets say that headphones from Japan are miles ahead*.
   
   
   
  Quote: 





miky2011 said:


> Hi francisdemarte,
> 
> I tried with three differents op-amps : stock lovely 2134, stock lovely 2111AM and an original 2134 (wich appears in the photos) with the same result and same poor amplification.


----------



## francisdemarte

One more idea. Have you tested those DIP switches to make sure they are working? I read they can be easily damaged if you overheat them soldering them on. Put your meter on continuity test mode and make sure they go ON and OFF as intended.
   
  At this point you may want to consider sending the board off to someone close to debug for you. Where are  you located Milky?


----------



## miky2011

Francisdemarte,   DIP are working right. I have tested with multimeter the on/off function.
   
     I'm in Spain. Barcelona.
   
     You think that MKP1837 (22nF) capacitors round the opamp can have any problem? Its the only one that I have not change.


----------



## chetlanin

Quote: 





miky2011 said:


> Francisdemarte,   DIP are working right. I have tested with multimeter the on/off function.
> 
> I'm in Spain. Barcelona.
> 
> You think that MKP1837 (22nF) capacitors round the opamp can have any problem? Its the only one that I have not change.


 



 Too much guesswork, if you ask me. It is a very ineffective method. And why would 2 capacitors of good quality be defective? As far as I know nobody has complained about unreliable component delivered with the LC:

 You did everything right in the beginning, measuring the supply voltage and other important voltages, plus checked the orientation of components etc. Just continue with simple and logical measuring, and you will find the fault very soon.

 For example:
 1..Set your multimeter to measure small AC voltages. 2. Send a signal to the head-amp, preferably a sinus tone (you can download test tones, or a free tone-generator for PC like ’Sigjenny’). 3. Now measure, say, at the input and the output of the op-amp etc. Is there amplification?

 Remember to set the dip switch to amplification, and to turn up the volume..

 AC measuring of the signal will not destroy the amp. (one must be more careful when measuring resistances, because a current then is sent through the circuit).



 BTW:
 You are aware that electrostatic discharge easily can destroy the sensitive input section of an op-amp? Both your op-amps may be defective for the same reason, if the problem boils down to the op-amp. At least it can not be excluded. (Never mount an op-amp without touching the ground of the amplifier with the same hand before the pins are making contact, and moist skin is an advantage).
   
  Olaf


----------



## JiggaD369

EDIT: NVM. I figured it out.
   
  I'm loving Elna Silmic's filtering the Opamp! Can't wait to pair it with some Polystyrenes!


----------



## HydronQc

Would the Lovely Cube Premium be a good amp for My ultrasone 750?
  Stock, Dual OPA627 or OPA2111AM?


----------



## francisdemarte

I think I have a new favorite op amp: NJM2903
   
  I just finished building the much talked about O2 Amp which uses this op amp. It's excellent for the price and was an easy build. The sound is very clean and clear and tips more toward the neutral side compared to the warmer sounding stock LC.
   
  On a whim I decided to try the NJM2903 op amp in the LC. If you like a sound that a little less laid back and more treble oriented than the OPA627 than this is well worth a try. It's also dirt cheap at $0.39/chip at Mouser.
   
   
   
http://www.mouser.com/ProductDetail/NJR/NJM2903D/?qs=sGAEpiMZZMuS%2fmO2LfY7hmY4WczzinzbK0Vhar5ZiHI%3d
   
  datasheet: http://semicon.njr.co.jp/njr/hp/productDetail.do?_isTopPage=false&_productId=951&_moveKbn=PRODUCT_DETAIL_MOVE_SPEC


----------



## BlackstoneJD

FYI,
   
  The new Lehmann Linear SE was recently shown in Australia with an RRP of $3,199 Australian. That means it will be over $3,000 in the United States. The biggest change advertised is a switch to Mundorff capacitors. Wow!


----------



## francisdemarte

_The new Linear SE, equipped with Mundorf caps in its power supply and signal path as well as a gold-plated AHP microfuse, rests vibration neutral on custom-designed SSC feet. For the interior wiring we used products from the Japanese maker Mogami. Housings made of cool, satin mat aluminium in six homely, noble real wood veneer versions (designed by Guido Gutenstein) protect the superior Lehmannaudio technology and represent a high aesthetical added value._
   

 So we have:
   
  1. Mundorf Caps (You can buy them here http://www.madisoundspeakerstore.com/supreme-caps/)
  2. Fancy Fuse
  3. Rubber feet
  4. Mogami wire (if you notice the picture there not a lot of wiring since everything is on the board. You may just need a foot or so (http://www.studiowiring.com/mogami.html)
  5. New case design
   
  Somehow all that adds up to $2000 extra?!


----------



## BlackstoneJD

I know it is insane.


----------



## JiggaD369

Quote: 





francisdemarte said:


> _The new Linear SE, equipped with Mundorf caps in its power supply and signal path as well as a gold-plated AHP microfuse, rests vibration neutral on custom-designed SSC feet. For the interior wiring we used products from the Japanese maker Mogami. Housings made of cool, satin mat aluminium in six homely, noble real wood veneer versions (designed by Guido Gutenstein) protect the superior Lehmannaudio technology and represent a high aesthetical added value._
> 
> 
> So we have:
> ...


 
   
  But..but..what about the R&D costs? 
	

	
	
		
		

		
			




   
  In other news, I finally got started modding my LC since I have some time on my hand and with each step the sound is becoming more and more sonic orgasm. Literally.
   
  So far I've done the follwoing:
   
  Bypass input caps.
  Silmic II 470uf for the Opamp supply.
  NOS .027uf Philips Polystyrene Caps bypassing the above.
  Panasonic FM swapped for those four 470uf PSU electrolyics. 
   
  Still to do:
   
  Change output resistors (FlukeII method)
  Change the 47ohm resistors on pin 8 of opamp.
  Change the 4700uf caps.
  Add 220uf Muse ES caps to the Silmic's (worth it?...Got plenty sitting here)
  Bypass the four PSU eletrolytics (worth it?...Got plenty sitting here also)
  Change the ADJ caps for 10uf tantalums.
   
  Moreover, I was reading the Jaycar DIY amp forum over at RockGrotto for some ideas and I constantly came across the name JHL Ripple Eater project which seems like a interesting idea. Think it might help us?


----------



## BlaBlaBla

Quote: 





blackstonejd said:


> FYI,
> 
> The new Lehmann Linear SE was recently shown in Australia with an RRP of $3,199 Australian. That means it will be over $3,000 in the United States. The biggest change advertised is a switch to Mundorff capacitors. Wow!


 

  
  Quote: 





francisdemarte said:


> _The new Linear SE, equipped with Mundorf caps in its power supply and signal path as well as a gold-plated AHP microfuse, rests vibration neutral on custom-designed SSC feet. For the interior wiring we used products from the Japanese maker Mogami. Housings made of cool, satin mat aluminium in six homely, noble real wood veneer versions (designed by Guido Gutenstein) protect the superior Lehmannaudio technology and represent a high aesthetical added value._
> 
> 
> So we have:
> ...


 
   
  I had started to laugh so hard that my tears were running in streams. After few minutes I ended up in hospital. Final diagnosis was - "jaw dislocation and dehydration".
   
  Ten years ago, I used to watch Benny Hill. Today I read advertisements about HIFI equipment.


----------



## nsk1

BUT MOGAMI WIRE! Everyone knows it's the best thing since sliced bread.


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> But..but..what about the R&D costs?
> 
> 
> 
> ...


 
   
  Pin "4" and pin "8". Those are in power supply. You can change stock 47R resistors with low inductance metal film type, but that is not good chioce. You will get more "grainy" sound (more noise) because low inductance resistor will alow high frequency from LM regulators to pass thorugh (and come to opamp +/- supply). But resistor in output (pin "1" and pin "7") must be the best what you can get because through them signal goes to transistors. Here inductance (and capacitance) must be zero.
   
  Don't go to low with ESR after LM regulatros. They will start to oscillate. In datasheet is written allowed output resistance (usually between 0.01R and 0.001R) that depends on frequency. This means that you have know ESR curve of electrolytic capacitor and be sure that ESR will never go below allowed resistance.
   
  Most people claim that Tantalum capacitors are bad in circuits, but in LM regulators (Cadj value) they are miles ahead over electrolytic capacitor (low leakage current). If you can put MKT/MKC or MKP in Cadj - fine. But it will cost you a lot. (10uF 63V MKT is big and expensive).
   
  Cadj and R2 resistor have big influence on noise. LM regulator likes when R2 is very small. The smaller the R2 is, the bigger effect will have Cadj capacitor. But because you have to devide something (1+R2/R)*1,25V= Vout, you can't go lower than R2=1k1. There is a trick to have lower resistance but the same output voltage - zener diode. Zener diode has 10 times smaller resistance and it will give you something between 14.2 and 14.5 volts on output. Use two (13V, 1W) zener diodes in a parallel connection (not because resistance - this rule does not work here, but for safety) in each LM regulator. Try to find good quality diodes because difference between + and - supply will be less. As far as Cadj goes, Tantalum capacitor are small and have "punch" in sound. Better are MKT/MKC/MKP but also bigger (won't fit here). Electrolytic are too mellow and you have to deal with safety diodes that have to limit output voltage (in LM regulator Vout mustn't go above Vin).
   
  You can change input capacitors (4700 uF) with 2x2200 uF or something like that. Response might be better (lower resistance).


----------



## JiggaD369

Quote: 





blablabla said:


> Pin "4" and pin "8". Those are in power supply. You can change stock 47R resistors with low inductance metal film type, but that is not good chioce. You will get more "grainy" sound (more noise) because low inductance resistor will alow high frequency from LM regulators to pass thorugh (and come to opamp +/- supply). But resistor in output (pin "1" and pin "7") must be the best what you can get because through them signal goes to transistors. Here inductance (and capacitance) must be zero.
> 
> Don't go to low with ESR after LM regulatros. They will start to oscillate. In datasheet is written allowed output resistance (usually between 0.01R and 0.001R) that depends on frequency. This means that you have know ESR curve of electrolytic capacitor and be sure that ESR will never go below allowed resistance.
> 
> ...


 

Hey bla, I ordered:
   
1. CMF55 1%/500mw/50ppm 47.5ohm resistors for pin 1 and 7. Good choice or throw them in the trash?
2. Is BZX85C13 fine for the two zener diodes in parallel for R2?
3. Vishay Sprague 199D 10uf/25V tantalum for the ADJ caps.
4. Vishay BYV27-200-TR for rectifiers.
5. 470uf Panasonic FC to change out for the four FM I put in yesterday.
5. EKMH500VSN472MQ35T for 4700uf swap.
6. 100pf Polystyrene.
7. MBB02070C3019FRP00 (3x30 ohm in parallel) for FlukeII method of the 10hm output resistor.
8. Vishay CMF/RN 1%/50ppm for all signal path resistors. The only reason I ordered these was because I checked the resistor values on the amp yesterday and some of them were +/- 10%.
   
  I know alot of it is overkill but I'm very comfortable with DIY'ing now and my soldering has become very good. So why not?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Hey bla, I ordered:
> 
> CMF55 1%/500mw/50ppm 47.5ohm resistors for pin 1 and 7. Good choice or throw them in the trash?
> Vishay Sprague 199D 10uf/25V tantalum for the ADJ caps.
> ...


 

 CMF 55 (Dale) is excellent resistor (actually I don't know anything from Vishay that is less than excellent). Dale is excellent choice.
   
  In signal path always goes metal film. Dale is neutral. PRP is more smooth and airy. Holco is very transparent. Takman is more closed - I didn't like it too much.
   
  But in output path if you put metal film (3xMBB Vishay), you might find that sometimes sound is too harsh or metallic. Then you can put old but excellent Allen Bradley, that will smooth harsh edges and warm up all things little bit... Or you can go towards very fast and detailed Kiwame/KOA Speer resistor. I must say that I have never seen so detailed and neutral carbon film resistor like Kiwame. It behaves almost like metal film. But without metallic sound signature. For comparison (vs Kiwame) Riken Ohm is smoother and fluid, and Bradley more warm and has "body".


----------



## JiggaD369

Quote: 





blablabla said:


> CMF 55 (Dale) is excellent resistor (actually I don't know anything from Vishay that is less than excellent). Dale is excellent choice.
> 
> In signal path always goes metal film. Dale is neutral. PRP is more smooth and airy. Holco is very transparent. Takman is more closed - I didn't like it too much.
> 
> But in output path if you put metal film (3xMBB Vishay), you might find that sometimes sound is too harsh or metallic. Then you can put old but excellent Allen Bradley, that will smooth harsh edges and warm up all things little bit... Or you can go towards very fast and detailed Kiwame/KOA Speer resistor. I must say that I have never seen so detailed and neutral carbon film resistor like Kiwame. It behaves almost like metal film. But without metallic sound signature. For comparison (vs Kiwame) Riken Ohm is smoother and fluid, and Bradley more warm and has "body".


 
   
  HI Bla,
   
  Thanks for the input. IF the MBB don't sound too good than I'll order some Allen Bradley from ebay.
   
  But more importantly, Is BZX85C13 fine for the two zener diodes in parallel for R2?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> HI Bla,
> 
> Thanks for the input. IF the MBB don't sound too good than I'll order some Allen Bradley from ebay.
> 
> But more importantly, Is BZX85C13 fine for the two zener diodes in parallel for R2?


 

 Yes. It is.


----------



## JiggaD369

Quote: 





blablabla said:


> Yes. It is.


 


  Awesome!
   
  Hopefully everything is here tomorrow and I can solder it all in. Basically all will be modded except the transistors. I want to change them too but can't find any matched pairs. Any suggestions?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Awesome!
> 
> Hopefully everything is here tomorrow and I can solder it all in. Basically all will be modded except the transistors. I want to change them too but can't find any matched pairs. Any suggestions?


 

 Stick with new BD139/140 transistors. Do not buy "japanese" old stock because those are fakes (especially on e-bay). BD139/140 by Onsemi, Fairchild, etc... are genuine in 95%.
   
  This seller has old matched transistors but somewhat expensive. Youu have to be cautious. Sometimes it makes mistakes. I bought few things without problems.
   
  http://www.ebay.com/itm/4-X-MATCHED-ONSemi-MJE243-MJE253-POWER-TRANSISTOR-/150570180071?pt=LH_DefaultDomain_0&hash=item230eae9de7
   
  http://www.ebay.com/itm/4-X-MATCHED-ONSemi-BD139-BD140-MEDIUM-POWER-TRANSISTOR-/350237513136?pt=LH_DefaultDomain_0&hash=item518bc855b0
   
  I would buy 10 transistors (BD - Onsemi) of each type and measure hFE. Usually, this is good enough for audio. OR you can play safely and buy matched transistors from Banzaimusic. You can send them email about which transistors you need matched. But shipping is expensive so I suggest you buying something from Banzaimusic when you need lots of items.
   
  www.banzaimusic.com


----------



## chetlanin

Good transistor advices there from BlaBla!
   
  Worth trying are also these Hitachi types from the same seller:
   
  http://www.ebay.com/itm/4-X-MATCHED-HITACHI-2SB649-2SD669-POWER-TRANSISTOR-/350265318062?pt=LH_DefaultDomain_0&hash=item518d709aae
   
  The ones I use comes from an old private stock, but I generally I have rather good experience with the eBay seller in question, also.
   
  The pins outlay is identical to the original BD's..


----------



## francisdemarte

Quote: 





jiggad369 said:


> Awesome!
> 
> Hopefully everything is here tomorrow and I can solder it all in. Basically all will be modded except the transistors. I want to change them too but can't find any matched pairs. Any suggestions?


 

 Change one thing at a time and remember to test it between swapping components. You don't want to get into a situation where you change too many things at the same time and make troubleshooting too difficult.


----------



## Maverickmonk

Any suggestions for a good shielded transformer for US house-voltage? I know it's a terribly simple question but There's enough out there that I honestly don't know what to pick. Is 30v secondary windings a good choice? And what manufacturer would be a good choice?


----------



## francisdemarte

You want a transformer that has 2 15v secondaries. If your using the stock metal case you have to make sure your transformer fits. I think a 30VA Toroidal is cutting it pretty close. Anything bigger may be too tall to fit.


----------



## Tribbs

I have one brand new, still in factory box, Hammond 182M15 torroidal power transformer

 80 VA
 30V C.T. @ 2.67A
 15V @ 5.34A
   
  Diameter = 3.73 in
 Height = 1.52 in
 Weight = 2.15 lbs
   
  I think it would fit in the "Lovely Cube" or Matrix M-Stage (old ver. w/short PCB). 
   
http://www.hammondmfg.com/pdf/5c0024-25.pdf
http://www.hammondmfg.com/pdf/182%20Insert.pdf
   
  If interested PM me...


----------



## BlaBlaBla

Quote: 





maverickmonk said:


> Any suggestions for a good shielded transformer for US house-voltage? I know it's a terribly simple question but There's enough out there that I honestly don't know what to pick. Is 30v secondary windings a good choice? And what manufacturer would be a good choice?


 


 Hand made 80VA EI core...


----------



## lokesen

I am selling mine - it's with OPA627 bias and the good Telama transformer - only 10 days old and like new - here is the auction if interested:

http://www.ebay.co.uk/itm/140656399470?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649#ht_500wt_1413
   
  I really love it and it sound awesome with my HD 650 and Shure IEM's - but it's not a good match for my ortho dynamic T50rp - so I am looking for a tube amp instead. Unfortunately I can't afford two good amps


----------



## BlaBlaBla

Quote: 





lokesen said:


> I am selling mine - it's with OPA627 bias and the good Telama transformer - only 10 days old and like new - here is the auction if interested:
> 
> http://www.ebay.co.uk/itm/140656399470?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649#ht_500wt_1413
> 
> I really love it and it sound awesome with my HD 650 and Shure IEM's - but it's not a good match for my ortho dynamic T50rp - so I am looking for a tube amp instead. Unfortunately I can't afford two good amps


 
   
  This is real thing...
   
  http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=ahammer2_prj.htm


----------



## JiggaD369

Hey guys,
   
  Bummer!
   
  I finally got my components in today and took about 2 hours to swap everything in.
   
  I know I should've done it one component at a time like francis told me but I got impatient last week and desoldered everything I was going to swap out. Big mistake. 
   
  When I got done today and turned on the amp, everything turned on fine. NO smoke, no sparks. When I plugged in the headphones, I noticed that the amp was distorting at very high volume (my phones are 600ohm) so something definitely got messed up correct?
   
  Then I proceeded to find out how to check voltage on the regulators to see if they were working fine and accidently shorted it so now the amp doesn't work anymore. Ugh!
   
  I see that one yellow led turns on while the other doesn't. Could the short have blown other things out also?
   
  Does Stephen sell just the PCB itself so I can transfer all t he components on there or am I screwed?


----------



## francisdemarte

Post up a high res picture of your board, top and bottom and indicate the parts you changed. I think part of the problem is your opamp is fried.


----------



## JiggaD369

Quote: 





francisdemarte said:


> Post up a high res picture of your board, top and bottom and indicate the parts you changed. I think part of the problem is your opamp is fried.


 


  HI francis,
   
  Thanks for your help! 
   
  I know you told me to be cautious but I had already desoldered the components to be swapped in before you told me to. Rookie mistake!
   
  Here are the pics. It weird about the distortion because it would be very distorting if turned up all the way but if the knob was half way it would sound awesome. So it being a opamp problem would be calming since I have extra opamps.
   
  The changes are left to right:
   
  2x 4700uf/50V big tanks.
  LM317/337 w/ 10uf/25v tantalum ADJ caps
  4x Panasonic FC 470uf
  100pf Polystyrene
  3x30 ohm output resistors (FlukeLL method)
   

   
  https://picasaweb.google.com/lh/photo/Ng22NLK0znjl7_Aofu0BesPL_whp-Nux81KiuQ2TPds?feat=directlink
  https://picasaweb.google.com/lh/photo/7R6meOSAmUpHU8lg-4vzEsPL_whp-Nux81KiuQ2TPds?feat=directlink


----------



## francisdemarte

Unplug it and let everything cool down.
   
  I can't tell from you picture but make sure there are no bridges between any solder joints. The ones from the new regulator look almost like they are touching but that can be from the angle of the photo.
   
  Leave the opamp out. No headphones plugged in. You might want to use a set of cheapies to test and not your main phones!
   
  Do both LED's come on?
   
  Make sure the regulators aren't getting super hot.
   
  Carefully measure the following.
   
  What voltages are you getting across pins 7 and 4 of the opamp socket?
  Between pin 7 and Ground?
  Between pin 4 and ground?


----------



## JiggaD369

Quote: 





francisdemarte said:


> Unplug it and let everything cool down.
> 
> I can't tell from you picture but make sure there are no bridges between any solder joints. The ones from the new regulator look almost like they are touching but that can be from the angle of the photo.
> 
> ...


 

 HI francis,
   
  Sorry for the stupid question but the meter is supposed to be on 20v - DC correct?
   
  If so,
   
  Between 4 & 7 = 1.36V
  Between 7 & Ground = 0.08V
  Between 4 & Ground = 1.27V
   
  Only one yellow led comes on. Sound is very distorted.


----------



## francisdemarte

That's way too voltage between 4 and 7 should be closer to 15v. So the problem is further back along. 
   
   
  First make sure your transformer is outputting +-15v AC into the board
   
  Next check the Vin and Vout of the two regulators you replaced.


----------



## JiggaD369

IS it too low?
   
  Could it be because the MM lead accidently slipped and touched two leads on the LM337?


----------



## francisdemarte

With one of the leds not lit, either the neg or the pos power supply side is not working right (maybe the led is fried?)
   
  Anyway the regulators are pretty robust. A short slip is unlikely to kill them, it will send them into protection mode where they shut down completely for a while, as you saw.
   
  First are you 100% sure your transformer is wired correctly?
   
  Which led isn't working? Follow the traces back to the regulator and check the output. They are pretty easy to follow from the back of the board.
   
   

   
  Try cross posting this to the M-Stage thread too.


----------



## JiggaD369

The MM should be on AC right?
   
  For some reason, the transformer leads are coming up at 19.2V. What in the world??? Shouldn't it be 15V?
   
  THe LED that is toward the big 4700uf caps is not lighting up. The other one (towards the edge) does light up.
   
  I was following traces and there is a weird find. The four eletrolytic caps..two of them that connect to the LM337 (the one that made the spark when I was checking the voltage) stop as a certain resistance when I do a resistance test. The other two connected to the LM317 keep rising up in resistance as a working cap should be.
   
  The voltages on the regulators are:
   
  LM317 - Vin is 24.4V and Vout is 3.65V
  LM337 - Vin is -24.4V Vout is -1.2V


----------



## lokesen

Quote: 





blablabla said:


> This is real thing...
> 
> http://gilmore2.chem.northwestern.edu/projects/showfile.php?file=ahammer2_prj.htm


 


  Wow - that looks awesome!


----------



## BlaBlaBla

Quote: 





francisdemarte said:


> Post up a high res picture of your board, top and bottom and indicate the parts you changed. I think part of the problem is your opamp is fried.


 

 Opamp is not fried. Short circuit was before opamp. Regulators are down.
  Opamp is very robust and only thing that can kill it is potential spike or electrostatic spike.


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> The MM should be on AC right?
> 
> For some reason, the transformer leads are coming up at 19.2V. What in the world??? Shouldn't it be 15V?
> 
> ...


 

 19V after bridge rectifier if you have 2x15V AC transformer
  22,5V after bridge rectifier if you have 2x18V AC transformer
   
  15V AC RMS goes to 1.41x(15-Vd). It is between 18V and 20V (depends on diode Vdrop and depends if it is double bridge or single bridge)


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> The MM should be on AC right?
> 
> For some reason, the transformer leads are coming up at 19.2V. What in the world??? Shouldn't it be 15V?
> 
> ...


 
   
  Wait for two hours, I will check my setup and we will see...


----------



## JiggaD369

Quote: 





blablabla said:


> Opamp is not fried. Short circuit was before opamp. Regulators are down.
> Opamp is very robust and only thing that can kill it is potential spike or electrostatic spike.


 

 HI bla,
   
  I have ordered new regulators.
   
  Quote: 





blablabla said:


> 19V after bridge rectifier if you have 2x15V AC transformer
> 22,5V after bridge rectifier if you have 2x18V AC transformer
> 
> 15V AC RMS goes to 1.41x(15-Vd). It is between 18V and 20V (depends on diode Vdrop and depends if it is double bridge or single bridge)


 

 But I'm getting 19.2V AC straight from the transformer leads..they're weren't even attached to the board.
   
  Quote: 





blablabla said:


> Wait for two hours, I will check my setup and we will see...


 

 Thanks for your help!


----------



## francisdemarte

I've killed a couple of opamps before with too much voltage, but I've never *so far* been able to kill a regulator.
  Hopefully we'll get to the bottom of this when Bla comes back with his readings.


----------



## Maverickmonk

Is a dual 18v overkill? I'll be driving both low and high impedence headphones, so any chance to get some overhead I'd like to take. Or should I just play it safe and go with the stock 15v
   
  http://www.ebay.com/itm/Toroidal-Transformer-15VA-P-115-230V-S-Dual-18V-/400244739603?pt=LH_DefaultDomain_0&hash=item5d30720e13
  
  http://www.ebay.com/itm/Toroidal-Power-Transformer-15VA-Secondary-2x15V-Primary-115V-230V-/130612139500?pt=Vintage_Electronics_R2&hash=item1e691715ec
  Quote: 





francisdemarte said:


> You want a transformer that has 2 15v secondaries. If your using the stock metal case you have to make sure your transformer fits. I think a 30VA Toroidal is cutting it pretty close. Anything bigger may be too tall to fit.


----------



## francisdemarte

I use a transformer that outputs 18V and it is fine. Although I don't hear any improvement going from 15V to 18V. Keep in mind that I have a custom enclosure and my transformer is in separate box. If your using the stock enclosure makes sure the larger tranny fits.


----------



## BlaBlaBla

I have Talema 2x15V toroidal transformer (30 VA) that has 17.1V on output. Also have custom made EI transformer (80VA) that has 15.5V on output. It seems that custom made transformers might be more precise because they are hand made and turn ratio is strictly controlled by maker. But that does not have any effect on results.
   
  Lets start with voltages.
   
  I admit I have made mistake. After rectifier there is 21V. It is 1.25xVac. With rectifier that has 8 diodes it is less...
   
  Regulator
  Vin=21V
  Vadj(below LM)= 13V (because I have 13V zener there)
  Vout=14.2V - (because Vout voltage is calculated like Vzener+Vreference. Regulator reference voltage is between 1.2 and 1.3V for almost every good working LM 317 and 337. If you use zener instead R2 you can calculate voltage Vout=Vzener+1.2V)
   
  After resistors (47ohm) and before opamp voltages depend on current that is needed for opamp. There I have 14.2V (and -14.3V-but id doesn't matter because this depends on regulator Vout that is not equal without trimpot tuning (instead fixed R2) on Vadj.).
   
  DC offset on headphone out is the same through entire volume range (about 6 mV).
   
  Try to measure Vadj. It has to be Vout-1.25V. If Vadj is very small and resistor R2 is not burned then something is wrong with tantalum. Tantalum capacitors are very sensitive. Sometimes tantalum may act as diode. My friend had four cases like that (but in 25 years of work with electronics in TV and VCR stuff).
   
  Also try to measure DC offset without opamp pluged in (NEVER LEAVE YOUR HEADPHONES CONNECTED TO AMPLIFIER WITHOUT OPAMP because if circuit is on the edge of stability headphones load might it make unstable. In this way I killed AKG K701.). It must be close to DC offset with opamp. If it is not, that means that your circuit is oscillating. It may happen if LM regulators are oscillating. LM regulators can oscillate if electrolytic capacitors have too big resistance or even worse - to little. Tantalum in Vadj is crucial for stable operation because it allows you to put (after regulator) capacitor with less resistance. If someone tries to force 4 panasonic FM (1000+ uF) on output, regulator will start to ring and it may happen that you have 3-5 volts DC on headphone output with and without opamp.
   
  If you have multimeter you can try to measure current that flows through supply. Measure on both lines (+ and -). It has to be equal. If the current is close to 1A or more, that means that something is wrong with transistors (in 95%) or that something has happened after regulators circuit (I guess that regulators are working fine so it might be that capacitor is broken).
  Strong distortion on high volume levels might be connected with type of opamp. AD opamps are not good for this type of supply. They are too fast. Sometimes people say that in Lovely Cube AD opamps are "bright", "fast", "aggressive", etc... That is because they are on the edge of oscillation. Slow opamps are safe bet. For example OPA2107. OPA2107 has the same DC offset through entire range and gain (0, 10, 18, 20dB). Just opposite, LME has offest that goes up within volume band raises slowly with gain (8mV to 18mV). This means that LME does not like changes in input resistance and needs steady resistance, OR FEEDBACK (that LC does not have). Furthermore, AD797 (the best, the fastest, etc...) opamp starts with 10mV and in high gain has huge amount of DC offset (100mV and more) which means that is not good for this kind of setup, at all.
   
  Without oscilloscope I would say that entire setup works fine if DC offset, with and without opamp, is the same. Try to measure that. Do not buy other stuff and change parts, maybe error is trivial and can be solved easy. If you have plans to change regulators do not pull out entire regulator. Just cut out the body of the regulator and leave legs in PCB. Cut out legs on new regulator just enough to be able to connect new body on old legs. Then solder that connection. Solder can withstand 170 C (WBT), or 190 C (Cardas) or 210 C (Mundorf, and other stock products). If something goes hot that much, melt down of a connection would be the smallest problem.


----------



## BlaBlaBla

Quote: 





francisdemarte said:


> I use a transformer that outputs 18V and it is fine. Although I don't hear any improvement going from 15V to 18V. Keep in mind that I have a custom enclosure and my transformer is in separate box. If your using the stock enclosure makes sure the larger tranny fits.


 

 Usually benefit of bigger voltage is so small that it is limited with other parts of a circuit. It only matters if opamp is made for bigger voltage. For example OPA604 has sweet spot between +/-15 and +/-18V (it depends on power supply). There it has the best characteristic. OPA2134 works the best under +/-14V. Etc... If someone goes to bigger voltage he has to take care about resistors near transistors. Current through BC550/560 will be bigger and BC is the weakest part. I put 1k resistors, but voltage is +/-13.5V. I wouldn't let higher voltage through without making bigger distance between BC and BD (heat dissipation) or placing bigger heatsink on BD (to cool down them).


----------



## JiggaD369

Quote: 





blablabla said:


> I have Talema 2x15V toroidal transformer (30 VA) that has 17.1V on output. Also have custom made EI transformer (80VA) that has 15.5V on output. It seems that custom made transformers might be more precise because they are hand made and turn ratio is strictly controlled by maker. But that does not have any effect on results.
> 
> Lets start with voltages.
> 
> ...


 
   
  Hi Bla,
   
   
  A. I checked the volatges on the regulators again and they are:
   
  LM317 - Vadj is 2.4V, Vin is 23.7V, and Vout is 3.6V
  LM337 - Vadj is 0.0V, Vin is -23.7V, and Vout is -1.27V
   
  According to your measurements, it looks like they're blown?
   
  B. At the 47ohm resistors before the opamp, I'm getting two different reading on both resistors. It's 3.6V on the Left and -1.2V on the Right.
   
  C. R2's seem fine. Should I swap them out for the 13V zeners I ordered?
   
  D. But the Tantalum that was connected to LM337 ADJ pin is ringing when I do a continuity test so thats blown, right?
   
  E. DC offset on the headphone jack is 160mv.


----------



## francisdemarte

Do you still have your old regulators? Can you swap them in place of the LM337 to test?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Hi Bla,
> 
> 
> A. I checked the volatges on the regulators again and they are:
> ...


 

 Do not plug in your headphones. This offset is almost to big for speakers!
   
  1. Pull out tantalum capacitors and measure Vout. Regulator can work without Cadj (tantalums) and LM will show good Vout voltage if tantalums were bad. If you have multimeter in the same time, you can measure capacitance on pulled out tantalums. But watch out for polarity. Tantalum capacitors will blow of if there is reverse polarity for more than 2% of nominal value.
   
  Yes. It is strange if measure resistance over R2 and get ringing. Probably blown tantalum. If there were zener diode instead R2 resistor, it would protect tantalum because zener diode wouldn't allow voltage over its nominal value (12V, 13V or any voltage that your zener has). Also zener wouldn't allow reverse voltage that usually kills tantalum capacitors.
   
  2. If Vout is still bad (without tantalum) then you can cut out old LMs and install a new one. Leave nodes (legs from old LM) in PCB. Measure Vout again.
   
  3. If Vout is still bad then you try to see what is happening with capacitors after regulator (FC). Simple test is, after turning the amplifier on, to check voltage on capacitor cap (top position where cross is - where capacitor pops if it is under great overvoltage or stress). Two capacitors must have very very low voltage on their cap (two capacitors connected after positive LM317) and two must have negative voltage close to Vout (two connected after negative LM337).


----------



## JiggaD369

Quote: 





blablabla said:


> Do not plug in your headphones. This offset is almost to big for speakers!
> 
> 1. Pull out tantalum capacitors and measure Vout. Regulator can work without Cadj (tantalums) and LM will show good Vout voltage if tantalums were bad. If you have multimeter in the same time, you can measure capacitance on pulled out tantalums. But watch out for polarity. Tantalum capacitors will blow of if there is reverse polarity for more than 2% of nominal value.
> 
> ...


 

 Hi Bla and francis,
   
  I never plugged anything into the amp after the accident happened.
   
  I pulled the tantalums out. The LM337 tantalum is blown. The other one (LM317) is not blown. What is the orientation of the tantalum that should go into the amp? I thought they were non-polar.
   
  Here are the voltages after I removed the tantalums and four zeners installed:
   
  LM317 - Vadj is 13.2V, Vin is 21.7V, and *Vout is 14.5V*
  LM337 - Vadj is -12.8V, Vin is -21.7V, and *Vout is -14.1V*
   
  Another thing, ALL leds DO light up now.
   
  Lastly, DC offset is about 14-16mV after I plugged in a new OPA2111KP.


----------



## francisdemarte

Awesome news!
   
  I hope Milky also sees this and gets his LC up and running too.
   
  PS: One day I should consolidate all the BlaBlaBla mod's and put them on the first page. 
   
  I just noticed that this thread is almost 1000 posts!


----------



## JiggaD369

Quote: 





francisdemarte said:


> Awesome news!
> 
> I hope Milky also sees this and gets his LC up and running too.
> 
> ...


 
   
  HI francis,
   
  I thought 15mV was safe enough for 600ohm headphones so I took a chance and plugged them in. SOUND! lol.
   
  IT sounds good..going to wait on things burning in before I make a judgement on the overall sound.
   
  But, I see that the loudness level has gone down a little bit. I'm on 20db gain right now and I used to use 18db before to get the same level of output as right now. Any reason why this is happening?


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Hi Bla and francis,
> 
> I never plugged anything into the amp after the accident happened.
> 
> ...


 

 Tantalum capacitors have small sign on their body. Usually sign is "+". In circuit where LM317 is, "+" sign goes towards Adj and "-" to GND. In the circuit where LM337 is "+" sign goes towards GND and "-" towards Adj pin. Zener diode behaves in the same way. LM317 - black mark is close to Adj. LM337 - black mark is close to GND.


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> HI francis,
> 
> I thought 15mV was safe enough for 600ohm headphones so I took a chance and plugged them in. SOUND! lol.
> 
> ...


 

 15mV is safe for 600 Ohm headphones.
   
  Loudness might be slightly lower because tantalum Adj capacitors give extra punch. It is interesting that tantalum capacitors give the most power to the sound (if we compare them to other capacitors). It seems that LM regulator is optimised to work with tantalum Adj cap. You should put in Adj tantalum (or something else) because without them your opamp supply suffers a bit. Transistors represent huge load compared to opamp. Big loads makes big voltage drops and that is represented as "noise" - to opamp that represents very small load. If that noise is in high frequency region big electrolytes can't smooth it because they are too slow (fast transistors will make more high freq noise and bigger peaks). So you need fast capacitors (Vout cap) Vout cap is 150nF. It smooths high frequency. Electrolytic cap (before transistors) are like energy tanks AFTER REGULATOR. They supply transistors with current when LM starts to sag because bigger demands.
   
  Cadj has influence on entire picture because it doesn't smooth peaks and drops AFTER REGULATOR, it smooths bigger voltage drops that are made IN REGULATOR ITSELF because load after regulator. Here it is crucial that Cadj has leakage close to none, that has big current ripple, that has the same resistance over wide frequency range and that capacitance doesn't change too much with temperature. (Tantalum has all of this and it is very small. MKC/MKP is even better but 10x bigger and 20x more expensive. Electrolytic has big leakage, changes with temperature, variates with frequency and have bad ripple current ratio vs capacity )
   
  Conclusion is that the bigger Cadj is, the less will output capacitors have to supply transistors and the less will small loads (opamp) suffer because big loads (transistors). But too big Cadj (over 20uF) is not good because it might damage LM regulator. Positive LM regulator will die if output voltage is bigger than input voltage - the case when current would flow in opposite direction (from out to in). Negative regulator is opposite than positive.
   
  Sorry for bad english.


----------



## JiggaD369

Quote: 





blablabla said:


> 15mV is safe for 600 Ohm headphones.
> 
> Loudness might be slightly lower because tantalum Adj capacitors give extra punch. It is interesting that tantalum capacitors give the most power to the sound (if we compare them to other capacitors). It seems that LM regulator is optimised to work with tantalum Adj cap. You should put in Adj tantalum (or something else) because without them your opamp supply suffers a bit. Transistors represent huge load compared to opamp. Big loads makes big voltage drops and that is represented as "noise" - to opamp that represents very small load. If that noise is in high frequency region big electrolytes can't smooth it because they are too slow (fast transistors will make more high freq noise and bigger peaks). So you need fast capacitors (Vout cap) Vout cap is 150nF. It smooths high frequency. Electrolytic cap (before transistors) are like energy tanks AFTER REGULATOR. They supply transistors with current when LM starts to sag because bigger demands.
> 
> ...


 

 Very nice lesson! Thanks for the thorough info!
   
  I put in new tantalum caps and it changed up the volts on the regulators. I'm getting ~42V on the input and output is still at 14.5 and 14.1 volts on both regulators. Is this normal?
   
  ON the other hand, after all of these mods and improvements, I think the amp has come a long way of sound improvement. I actually heard the fibers of moving against the violin strings today. WOW!


----------



## francisdemarte

Jigga:
   
   How is the stepped attenuator working for you? I've always wanted to get one but was afraid that the 23 steps would not provide fine enough adjustments for me.


----------



## JiggaD369

Francis,
   
  I say definitely go for it! Not much a bank breaker IMO.
   
http://www.ebay.com/itm/DACT-Type-21-Stepped-Attenuator-Potentiometer-50K-D-/190606112871?pt=LH_DefaultDomain_0&hash=item2c61027867#ht_3156wt_1352


----------



## BlaBlaBla

Quote: 





jiggad369 said:


> Very nice lesson! Thanks for the thorough info!
> 
> I put in new tantalum caps and it changed up the volts on the regulators. I'm getting ~42V on the input and output is still at 14.5 and 14.1 volts on both regulators. Is this normal?
> 
> ON the other hand, after all of these mods and improvements, I think the amp has come a long way of sound improvement. I actually heard the fibers of moving against the violin strings today. WOW!


 

 +/-21V is OK.
   
  You will always have 14V on output because zener diode doesn't allow anything over 13V and LM regulation voltage is 1.25V. (13V+1.25V=14.25V). You can put there 2x36V transformer and voltage on output will be still around 14V. Zener diode replaced R2. Since you have 18VAC RMS transformer and output (after regulators) is less than 18V DC, you have big reserves. Probably regulators will heat more, but voltage will be stable (up to LM spec) because it is far above safety margin (Vtrans*1.25 - Vout(reg) = 2V).
   
  I am glad that you are satisfied. Sometimes there will be good results and sometimes bad. When you do something on your own, you always learn something new.


----------



## Tribbs

Quote: 





jiggad369 said:


> ...after all of these mods and improvements, I think the amp has come a long way of sound improvement. I actually heard the fibers of moving against the violin strings today. WOW!


 

 I havn't kept up with this thread.  Could you summerize what mods and improvements you performed?


----------



## JiggaD369

Quote: 





tribbs said:


> I havn't kept up with this thread.  Could you summerize what mods and improvements you performed?


 


  I basically went through the entire thread about three times in order to condense all of the info. This is basically my first complete DIY modding project and mostly out of curiosity. It was painful but worth it IMO!
   
  Below are the mods with Newark/Farnell part numbers (otherwise noted):
   
   
  PSU:
  Replaced the two 4700uf caps with United KMH caps (16M6799).
  Replaced the ADJ caps with Sprague10uf tantalums (30C8841).
  Replaced the R2 resistors with zener diodes as per BlaBla method (18C6023).
  Replaced the regulators with Fairchild (58K8936/58K8937).
  Replaced the four transistor 470uf caps with Panasonic FC (80K8337).
   
  Signal Path:
  Bypassed input caps with 6N copper wire.
  Replaced the stock opamp with OPA2111KP.
  Replaced the two opamp supply caps with Silmic II's. 
  Replaced the two small 0.022uf caps bypassing the Silmics with Philips (.027uf)  Polystyrene caps. (Ebay)
  Replaced the output 10 ohm resistors with Allen Bradley 1W carbon resistors (Ebay).
  Replaced the 100pf caps with LCR Polystyrene caps (64K0006)
   
  Let me know if I can be of any help if you plan to carry out any of the above!


----------



## Tribbs

Oh, this is great!  You saved me, and others I'm sure, much time.
  I couldn't bear going through this thread, yet again 
   
  Thank you!


----------



## francisdemarte

Quote: 





jiggad369 said:


> I basically went through the entire thread about three times in order to condense all of the info. This is basically my first complete DIY modding project and mostly out of curiosity. It was painful but worth it IMO!
> 
> Below are the mods with Newark/Farnell part numbers (otherwise noted):
> 
> ...


 
   
  Thanks so much! I've added your list to the first page of this thread. Once you get everything settled if you can post some pictures of your board it will be much appreciated!


----------



## Zsubbo

How can I reduce DC offset, I measured 17mV on the right channel, and 6mV on the left, witch resistors should I swap ?(It's worth noting, that I don't have the lovely cube, what i actually have, is an eBay clone of the BCL, but it's essentially the same thing IMO )


----------



## supertrichi

Hi there,
   
  just today arrived my LC, and I have some questions:
   
  1. The voltage regulators are National. Are they of good quality or I need to change them? I was thinking to use On-semi, will they be ok?
  2. Near them I found a strange component, I'm not sure, but it could be a trimmer ( see photo below). Is it for DC offset regulation?
  3. BD 139 and 140 are ST. I need to change them?
  4. Can you tell me the caps that I need to replace please?
   

   
  Thank you in advance


----------



## francisdemarte

Looks like it has BlaBlaBla's pot mod in there. Can you take a picture of your entire board?


----------



## BlaBlaBla

Quote: 





zsubbo said:


> How can I reduce DC offset, I measured 17mV on the right channel, and 6mV on the left, witch resistors should I swap ?(It's worth noting, that I don't have the lovely cube, what i actually have, is an eBay clone of the BCL, but it's essentially the same thing IMO )


 
   
  You can find matched BC550/560 transistors but it is not worth because soldering and de-soldering them is tricky process. The best way to low down DC offset in your amplifier is to replace 1k1 resistors with trimmer pot and 1K resistor in serial connection (that will make usable range from 1K to 1K2 which is enough for voltage tuning between 14V to 16V. Also you can put there one 2K trimmer pot but that I would not recommend because voltage tuning will be less precise AND trimmer pot has deviation (usually 2%) that can make your voltages different - every time when you turn on your amplifier. You can use vertical or horizontal trimmer pot. 100R resistor leave as it is.
   
  From my experience with LC topology I know that below 14V regulated DC voltage after regulators, DC offset on headphone out is negligible and you do not need matched transistors (BC and BD) and deviation in manufacturing process is enough tight. But when you try to use +/-18V DC and more, then matched transistors are of big importance. Unfortunately "matching transistors right on the table" is only the first part of story because when you match something that means that you need exactly the same environment for what you have matched. That means that matched transistors must always have the same temperature (transistor characteristic varies with temperature). So, it is not easy to do without custom made PCB and heat sinks. In old amplifiers that was done with 3 pin sockets that were soldered on the PCB and in there different transistors were placed and tried. When the lowest DC (or the best characteristic on the scope) was achieved transistors were soldered.
   
   


  Quote: 





supertrichi said:


> Hi there,
> 
> just today arrived my LC, and I have some questions:
> 
> ...


 

 1. Every voltage regulator that is genuine is good enough. Fakes are not good.
   
  2. This trimmer is for tuning DC voltage, From the picture I see that genuine topology has drawback, because there is no enough room for two trimmer pots. There only one voltage can be tuned. But that does not matter a lot and if your offset on headphone out is to high, then you can change voltage with this trimmer - and lower DC offset.
   
  3. BD made by ST is good as all others. Since Philips is gone there is no difference between all BD139/140 transistors. Person that worked in Phillips told me that Phillips was manufacturing transistors with tolerance under 1%. Today, all factories make BDs within 5% (5 times worse)...
   
  4.Caps that you could replace (try different) are those around opamp (MKT and Tin Foil) and electrolytic capacitors (470 uF) near BC/BD transistors and opamp. If you want to change capacitors near BD transistors do not go to high with capacitance and do not buy ultra low ESR capacitors because your regulators might start to ring (oscillate) in high frequency region. Furthermore I would personally (but that's me  ) change Cady capacitors (TWO green Vishay MKT 1822 - 0.15uF, the rest FOUR are in Vin and Vout circuit) with tantalum 10uF (watch out polarity) because this position is where tantalums are the best and this will give you more headroom for low ESR caps near BD regulators (less ringing - according to data sheet) and it will suppress voltage noises (according to data sheet).


----------



## supertrichi

This is the board.
   

   
  please don't hesitate to put signs in the parts that you suggest, I can change.
 Overall the caps, beacuse for the others components I understand.
  My doubts are  on the quality of ST and National ( now installed in my LC ) vs. Fairchild and On Semi.
 Will be an important upgrade?


----------



## BlaBlaBla

Quote: 





supertrichi said:


> This is the board.
> 
> 
> 
> ...


 
   
  The most important parts are transistors and capacitors. If you do not have matched transistors, changing those with another (unmatched) is not worth. Big influence in sound picture have high pass (DC blocking - in this case) and low pass capacitors. Second are opamp coupling capacitors and third are supply capacitors near transistors.
   
  1. Low pass filter (blue capacitors from the left side of OPAMP / close to ALPS pot) should be MKP/FKP or polystyrene. MKT/MKS does job but not enough. MKT/MKS is good for power supply -  not in the signal path.
   
  2. Try to replace coupling (yellow capacitors) near OPAMP with Polystyrene (Styroflex) 20nF or 10nF. Here is excellent place for them.
   
  3. Signal caps on input (DC blocking) have good voltage but bigger capacitance would be better (3,3 uF is good, more is better). If you are able, try to find MKT (10uF) and couple them with MKP. Or you can make good combination with big MKC 63V (4,7 uF) and fast MKP 250V (33 nF) in a parallel connection.
   
  4. Blue elcos near transistors are Philips BC?I changed them with Panasonic FC (NOT FM) and there is more depth and bass. But BC seems to have faster response (more bright). Cerafine and Silmic are too big and demand lower temperature environment (85C). You should go with capacitors that are ranked within 105C.
   
  5. Blue elcos near opamp. They are energy tanks and with resistor (47R)  they make RC filter. You can change them as elcos near BD transistors. I put here Panasonic FC. Others put here Cerafine, Silmic, etc... Be aware that Cerafine won't fit if it is bigger than 470 uF / 25V, and Silmic won't fit (at all) if it is bigger than 220 uF / 25V. Quality matters a lot (dielectric isolation or rated voltage). If it is rated as 50V it will have better characteristic than something rated as 25V. But, there is not enough place for 50V...
   
  6. This is trimmer pot. With it you can tune ONLY POSITIVE VOLTAGE (LM 317) and lower your DC offset.
   

   
   
  All this depends on other parts in your amplifier. The best would be if you change one part (for example input DC caps and opamp coupling) and listen to music. If your demands are satisfied - your tuning stops there. If you are not satisfied you might continue with upgrades. You can't be sure that other people choices will be the best bet because we all have different DAC, headphones, type of music, media (CD/MP3/DAT/WAV), different music tastes, etc, etc...


----------



## Zsubbo

Can you point out the resistors that you were talking about, because the closest I have is 1.5k resistors (actually 4 of them, so I think that you were talking about them) 
https://picasaweb.google.com/114049227892902856235/LehmannBCLCloneBuild?authkey=Gv1sRgCNij44XJxeb2eA - here a some pics of my build BTW.
   
  Thanks.


----------



## BlaBlaBla

Quote: 





zsubbo said:


> Can you point out the resistors that you were talking about, because the closest I have is 1.5k resistors (actually 4 of them, so I think that you were talking about them)
> https://picasaweb.google.com/114049227892902856235/LehmannBCLCloneBuild?authkey=Gv1sRgCNij44XJxeb2eA - here a some pics of my build BTW.
> 
> Thanks.


 
   
   
   
   
   
   
  These two. Resistors before opamp.  With 470uF capacitors they make RC filter that isolates opamp circuit. RC is used for noise and ripple suppression.


----------



## supertrichi

Quote: 





blablabla said:


> 1. Low pass filter (blue capacitors from the left side of OPAMP / close to ALPS pot) should be MKP/FKP or polystyrene. MKT/MKS does job but not enough. MKT/MKS is good for power supply -  not in the signal path.


 
   
  What is the right value of them ?


----------



## BlaBlaBla

Quote: 





supertrichi said:


> What is the right value of them ?


 

  Right value depends on frequency range that you want in your opamp. Stock capacitor is 100pF. Input impedance is variable and starts from 10k (when your volume pot is to max) and ends with 60k (when your pot is to min).
   
  With 100pF you will have:
   
  volume to max - 10k, 100pF - low pass filter = 160kHz
  volume to min - 60k, 100pF - low pass filter = 26 kHz


----------



## kyoshiro

man i want to order a LC Premium to try but apparently Stephen doesnt sell it locally (Hong Kong)


----------



## JiggaD369

Quote: 





francisdemarte said:


> Thanks so much! I've added your list to the first page of this thread. Once you get everything settled if you can post some pictures of your board it will be much appreciated!


 


  Hey Francis,
   
  Sorry for the delay but here you go...


----------



## supertrichi

Quote: 





francisdemarte said:


> Looks like it has BlaBlaBla's pot mod in there. Can you take a picture of your entire board?


 

 Hi Francis,
  what did you say was correct.
 I attach the Stephen's answer :
   
  "If I remember right , your board has a trimmer , which is used in order to make negative rail at the nearest voltage with positive rail.  LM317 output 15.01V and LM337 output 15.01V , and the DC offsets are very low indeed. You can measure them if you have a multimeter and if you know how to measure.  Taking extremely caution when measuring in order not to get electric shock and any shortage of circuit."


----------



## BlaBlaBla

Quote: 





supertrichi said:


> Hi Francis,
> what did you say was correct.
> I attach the Stephen's answer :
> 
> "If I remember right , your board has a trimmer , which is used in order to make negative rail at the nearest voltage with positive rail.  LM317 output 15.01V and LM337 output 15.01V , and the DC offsets are very low indeed. You can measure them if you have a multimeter and if you know how to measure.  Taking extremely caution when measuring in order not to get electric shock and any shortage of circuit."


 

 I wouldn't bother myself with voltage right out of regulators. I would give more attention to DC offset. Point is not in achieving equally voltages between negative and positive rail. Transistors have their own characteristic so if you want to pull out best from your setup then you must try to find voltages that will give you 0V (or close) DC offset on headphone out. When DC offset is close to 0V that means that headphone coils are right in the middle position and that means that their reaction will be exactly the same for negative and for positive voltage swing. This is very important for high frequency signal and for low impedance headphones. Even a low voltage can pull out coil on one side of driver and some dynamic is lost. Well, this is simplified description and the closest term that describes this behavior is: "some amount of DC offset will slow down headphone dynamics", more than that will fry their coils. Lets say that for Grado 50-80 mV AC is good enough for normal listening. And what happens if there is 15mV of constant DC offset? That is 1/5 of output signal. For high impedance headphones 15 mV is not so extreme because they need 200-300 mV AC for good listening. That is 1/15 of output signal.


----------



## taiyoyuden

quick noob connection: what gain should be used for the DT-770 80ohms?


----------



## Tribbs

Quote: 





taiyoyuden said:


> quick noob connection: what gain should be used for the DT-770 80ohms?


 
   
  Try 0 dB or 10 dB.


----------



## Dubstep Girl

so does this sound exactly the same as the original BCL?


----------



## BlaBlaBla

Quote: 





dubstep girl said:


> so does this sound exactly the same as the original BCL?


 

 No. But costs 4 times less.


----------



## sunneebear

Four is a understatement.  I believe when the BCL first came out it was $1200.


----------



## BlaBlaBla

Quote: 





sunneebear said:


> Four is a understatement.  I believe when the BCL first came out it was $1200.


 


  Still 2.5x less.


----------



## enigma211088

Does the BCL sound 4 times better is the real question?


----------



## Zsubbo

How do you measure 4x times better ??


----------



## BlaBlaBla

Quote: 





zsubbo said:


> How do you measure 4x times better ??


 
   
  The answer is subjective.
   
  In real world there is no equipment that will give you 4x better results if you compare two things that are working right. Let's say that amplifier A has noise level that is around  -80 dB, then amplifier B (4xbetter) should have -320 dB...
  Which is not possible in any case.
   
  Furthermore, below -90 dB - noise is non audible. Some people would give huge amount of money for something that they can't hear at all. Because HIGH number printed on the paper - looks good. And amplifier that is overwhelmed with "high numbers"  - "must be good".
   
   
_"I my garage I have Ferrari that is able to drive almost 200 Mph. _
_But I live in woods and use John Deere to get to work, because we do not have roads. _
   
_Do I need Ferrari?_
   
_...No. It is just waste of money._


----------



## Zsubbo

You are absolutely right !
   
  The other interesting question would be in my opinion, if someone, with great experience in headphone amps, but unfamiliar with the sound of the BCL, could distinguish on a blind test, witch one, the BCL or the Lovely cube is more expensive/better.


----------



## Dubstep Girl

i can successfully distinguish and identify different amp and headphone combos in a blind test.
   
  i know what headphone/amp i am using as well as being able to hear and identify the different tube combos/cables/mods/etc used in the system.
   
  i am THAT good.
   
   
  jk


----------



## Paul Clark

Quote: 





blablabla said:


> The answer is subjective.
> [...]
> 
> _"I my garage I have Ferrari that is able to drive almost 200 Mph. _
> ...


 


 Who are you to say how someone should spent the fruit of their own labour?


----------



## francisdemarte

Well different doesn't mean it sounds worse, just different.
   
  Personally I think the LC is pretty neutral with maybe slight touch of warmth. 
  What are you looking for in a amp?


----------



## BlaBlaBla

Quote: 





paul clark said:


> Who are you to say how someone should spent the fruit of their own labour?


 

 Nobody...
  My name is Nobody.


----------



## Paul Clark

I bet that useless Ferrari in your barn impresses the ladies 
	

	
	
		
		

		
		
	


	




 eh?
  Vrooom VROOOM....


----------



## BlaBlaBla

Quote: 





paul clark said:


> I bet that useless Ferrari in your barn impresses the ladies
> 
> 
> 
> ...


 

 Sure!  That is the reason why I bought it!


----------



## supertrichi

Hi there,
   
  After a pair of weeks of listenig, I tell you my impressions about the LC.
  The most surprising things about this amp are the differences I can hear between my 3 favourite headphones, which I know very well:

 D5000 -
 Great matching! This headphone is very warm and bass oriented, but the coupling with LC generate a perfect balance between all range of sound.
 Trebles are really precise, voices are great, the low range gets less bloomy, producing a warm and pleasant sound.

 K701 -
 Not so good as D5000 . The middle-high range, strongest point of this headphone, becomes tinny and unless extended as canned. Low range, weak point of the AKG sound, becomes worse, and the headstage (another great AKG characteristic) gets smaller.

 Sony MDR 7509 HD -
 Unrecognizable! The high range is analytic but becomes much cold , middle range is backward, and the low range is too much emphasized but totally out of control!
  Normally they are really precise, the opposite of what I heard with LC, I don't like it.

 This is everything about headphones, let's talk about opamps!
  By changing opamps, you can surely hear sound differences, but they are not so incisive and the don't change too much what I
  said about headphones.

 NE5532 famous opamp, it gives out an equilibrate sound, but it's a pretty normal component, not magic as I heard.

 OPA6104 better than NE5532, linear and accurate on the high range.

 OPA2604 and LME47920 *
 they are pretty similar and very pleasant, they also mix very well the low and the high range giving a warm sound.
  *without the box, this opamp has a little problem, I heard some treble distortion, which disappeared by closing the box.

 OPA627 accurate, balanced, perhaps tending warm, detailed, it's not always the best choice because sometimes it seems to be "away" without personality

 OPA2111AM the most detailed in the middle-high range, maybe a bit cold ant too much bright.
   

 CLASS A MOD
 I cannot hear any difference, and I think it turns nothing in class A.
 It has been a long time since I ended my studies, but I can't figure out how a resistor linked between ground
  and output could change the class of the opamp. ( 1, 4 pins are output - 7 pin is GND )
   

 Synthetically: I know I wrote a critic review, but it's what I heard, LC is well built, not magic and it's a pay for value. But attention to the coupling with various headphones.
   
  I'll modify LC following the suggestions I received in this forum
 .
  Thank you, BlaBlaBla and francisdemarte, Flukell and other


----------



## BlaBlaBla

Quote: 





supertrichi said:


> Hi there,
> 
> After a pair of weeks of listenig, I tell you my impressions about the LC.
> The most surprising things about this amp are the differences I can hear between my 3 favourite headphones, which I know very well:
> ...


 

 Nice review man!
   
  It seems that LC loves high current headphones from 32 to 64 Ohms. Grado works good too.
   
  95% agree about opamps. I can't say nothing about OPA627 because I think that don't have genuine TI. Agree about OPA2604. It shines with Grado too.
   
  It has to be connected between out and (-) or (+). Pin 1 is OUT A, Pin 7 is OUT B, and Pin 4 is (-).


----------



## Gabrielisc

Questions
   
  1) Do people with the HD800s believe the LC runs the headphones to its max capability (like the lehman would)
   
  2) Does anyone have a guide how to make a balanced lovely cube?


----------



## Tribbs

I think I'm going to order a Lovely Cube PCB kit and build one with a few upgrades.
  I was just wondering which and in what order, 1,2,3..., are upgrades worthwhile?
  Don't want to go overboard - limited budget


----------



## Mitroche

Hi,
   
  I have an AKG K701 and actually hesitate between M-Stage and Lovely Cube.
  Do you have an idea of which one will sound the best without making any mods except OpAmp swap ?
   
  Thanks a lot for your answer.


----------



## Tribbs

I do not beleive you would hear any difference as they are essentially the same amp clone of the Lehmann Black Cube.
   
  Low impedance cans =710]like the 62Ω K701 could benefit from a SS amp designed for low impedance loads like the DynaLo:
   
Sheer Audio H-006+ (I love mine with my 32Ω Grado 325i cans.)
Gilmore Lite
GS-1
   
  But, for a couple C-notes a Lovely Cube or Matrix M-stage are a good deal as is the Sheer Audio H-006+.


----------



## Mitroche

Thanks Tribbs.
   
  Do you mean Sheer Audio H-006+ is better on a purely technical point of view ?
 Price is not my first criteria and anyway Sheer Audio H-006+ is not much more expensive than M-Stage and LC.
  Sheer Audio H-006+ is available with x1, x3 and x11 gain. Which one would you recommend?


----------



## Tribbs

I can not give you a firm answer comparing the Lovely Cube/Matrix to the Sheer Audio as I do not have my Lovely, yet.
   
  In regards to gain for Sheer Audio. It was recommended by others here, as well as the manufacturer, to go with a gain of +3 with my Grados. That is spot on as I find my preferred volume setting on the Sheer Audio to end up between about 11-12 o'clock - perfect.
   
  The gain can be changed if neccessary.  The manufacturer will give you instructions.
   
  There is an interesting post in this thread
http://www.head-fi.org/t/589983/headamps-gs-x-vs-gilmore-lite-for-high-end-grado
  discussing some "high-end" Gilmore DynaLo amps that you may be interested.
   
  Pay particular attention to this review comparing two Gilmore DynaLo designs to the original Lehmann Black Cube of which the Lovely Cube & M-Stage are clones: http://www.head-fi.org/t/278691/six-way-review-square-wave-gs-1-canamp-ec-ss-gilmore-lite-black-cube-linear
   
  If I had the cash right now I'd dump everything and get a GS-X!  Err, or maybe settle for a GS-1


----------



## alexandre afons

i have a hd 800 and DAC1 USB and a headroom micro amp.I want to change the amp.The lovely cube is better than micro amp? Why?.


----------



## Tribbs

⁬I received my Lovely Cube kit and am now deciding which components to upgrade.  But I need some help.
   
  I happen to have a Hammond 182M15 80VA torroid that just barely fits inside the Lovely Cube's case.  I would like to use it but was concerned about power-up current surge (182M15 is rated 15V @ 5.34A).  With such a large surge of current filling the capacitors upon power-up I was wondering if I need to beef up some components in the power supply to prevent blowing the fuse or worse.
   
  FlukeII discusses changing the torroid on this page:
http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/390
   
  ...and BlaBlaBla mentions a larger torroid for the Lehmann BCL here:
http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures/30#post_7875531


----------



## Edoardo

Maybe I could not do this but please forgive me....
   
  If anyone has an assembled Lovely Cube to sell or wants to build up one for me...
   
http://www.head-fi.org/t/591891/lovely-cube-silver-assembled#post_8079558


----------



## Tribbs

Quote: 





tribbs said:


> ⁬I received my Lovely Cube kit and am now deciding which components to upgrade.  But I need some help.
> 
> I happen to have a Hammond 182M15 80VA torroid that just barely fits inside the Lovely Cube's case.  I would like to use it but was concerned about power-up current surge (182M15 is rated 15V @ 5.34A).  With such a large surge of current filling the capacitors upon power-up I was wondering if I need to beef up some components in the power supply to prevent blowing the fuse or worse.
> 
> ...


 

 BlaBlaBla was kind enough to repond to my question above in the Lehmann BCL thread here:
http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures/30#post_8080368
   
  Essentially, the only change that needs to be done to accomodate the larger, 80VA, torroid is to use a slow blow fuse (Slo-Blo 0.3A - 0.5A for 115Vac).
  Upon initial power up the larger torroid will draw a higher surge current from the AC mains which would likely blow the stock fast blow 0.9A fuse (115Vac).


----------



## Kcop

After being a read-only visitor at Head-Fi for some years, this is my first post on this forum, so please be kind if cut some corners.
  I've currently purchased some Beyer DT880/600 and while looking for an offordable and suitable solution i discovered the Little Cube, amon the Matrix M-Stage (New 2010 revision) and the Little Dot MKIII.

 Since all three amps are similarily priced I would like to know of you guys what you think, which of these three would be most suitable for my new cans. I'm also open to new suggestions beyond the three named amps, as long as they hit a similiar price-point.
 Eventhough I mostly listen to rock, I also got a hang of some other electronical or even 80's stuff, so maybe you could consider this while giving your opinion.
  The source will mostly be my PC playing FLAC files via my Infrasonic Quartet interface.
   
  I'm not sure if the LC would really fit my cans best after reading through a lot of posts in this thread, but I'm sure there are some experienced guys in here who can give a reliable statement regarding my issue.
   
  In case you recommend me to open a seperate thread for this, not to get this one specially regarded to the LC too messy, I'll do so.


----------



## Big Sky Audio

I have owned a Lehmann Audio BCL for over a year. This may not be the correct place to post regarding this amp but the upgrade mod that I have performed will apply equally to the Lovely Cube clone. I use Sennheiser HD-650s but have also used HD-800s and it is already well known that the Sennheisers match up extremely well with the BCL as they do with the Musical Fidelity X-CAN v3. In both cases, the synergy between the amp and phones is remarkable.
   
  First, get rid of the input capacitors as they are polyester type (notoriously bad for good sound) and replace them with polypropylene. They are expensive but well worth changing. The larger ones are 1.5uF in the LC but 2.2uF in the BCL. Next, I would replace the Op-Amp as the OPA2134 is good but the sound is lacking in the very lowest bass registers. After trying many different Op-Amps, my personal favorite is the OPA2604 and it does not matter whether it is the original BB or the TI/BB version. If you have any acoustic music with low bass in it you will notice right away that the very lowest bass is produced well with the OPA2604 but somewhat absent with the original OPA2134. It is my absolute favorite chip and prefer it over all others including a set of OPA627Bs I have on hand. I enjoy everything about it and the amp has more detail, is plenty fast, and much better on the low frequencies while the highs remain clear and unstressed. If you do not want to solder (best way) in your choice of Op-Amp then use a really high quality dip socket. I use the Swiss made Augat brand as they are high retention type with 4-fingered contacts for reliability. It is probably the next best thing to soldering it in place.
   
  Next, I would replace the six 470uF/35V electrolytics with Panasonic FC series and I took it one step further and replaced the Op-Amp decoupling caps with .1uF polyesters (they were .022uF originally). The main power supply capacitors were changed to Nichicon KG series Gold Tune Type II. The value was left at 4700uF each as that is more than sufficient capacity given the power level of the amp. From this point on, returns on investment with further parts changing produces diminishing returns. But I did replace resistors R13, R14, R21~R24 with PRP PR9372 metal film. The resistors used in local feedback for the Op-Amp (R21& R22) can be important and they can have a direct effect on the overall sound. Vishay Dale are very good with a neutral sound but I wanted the PRPs as they are non-magnetic and designed for audio purposes. I hope this has helped!


----------



## BlaBlaBla

Quote:


> Originally Posted by *Big Sky Audio* /img/forum/go_quote.gif
> 
> I have owned a Lehmann Audio BCL for over a year. This may not be the correct place to post regarding this amp but the upgrade mod that I have performed will apply equally to the Lovely Cube clone. I use Sennheiser HD-650s but have also used HD-800s and it is already well known that the Sennheisers match up extremely well with the BCL as they do with the Musical Fidelity X-CAN v3. In both cases, the synergy between the amp and phones is remarkable.
> 
> ...


 


  I like PRPs too. They are excellent.


----------



## proid

Quote: 





big sky audio said:


> I have owned a Lehmann Audio BCL for over a year. This may not be the correct place to post regarding this amp but the upgrade mod that I have performed will apply equally to the Lovely Cube clone. I use Sennheiser HD-650s but have also used HD-800s and it is already well known that the Sennheisers match up extremely well with the BCL as they do with the Musical Fidelity X-CAN v3. In both cases, the synergy between the amp and phones is remarkable.
> 
> First, get rid of the input capacitors as they are polyester type (notoriously bad for good sound) and replace them with polypropylene. They are expensive but well worth changing. The larger ones are 1.5uF in the LC but 2.2uF in the BCL. Next, I would replace the Op-Amp as the OPA2134 is good but the sound is lacking in the very lowest bass registers. After trying many different Op-Amps, my personal favorite is the OPA2604 and it does not matter whether it is the original BB or the TI/BB version. If you have any acoustic music with low bass in it you will notice right away that the very lowest bass is produced well with the OPA2604 but somewhat absent with the original OPA2134. It is my absolute favorite chip and prefer it over all others including a set of OPA627Bs I have on hand. I enjoy everything about it and the amp has more detail, is plenty fast, and much better on the low frequencies while the highs remain clear and unstressed. If you do not want to solder (best way) in your choice of Op-Amp then use a really high quality dip socket. I use the Swiss made Augat brand as they are high retention type with 4-fingered contacts for reliability. It is probably the next best thing to soldering it in place.
> 
> Next, I would replace the six 470uF/35V electrolytics with Panasonic FC series and I took it one step further and replaced the Op-Amp decoupling caps with .1uF polyesters (they were .022uF originally). The main power supply capacitors were changed to Nichicon KG series Gold Tune Type II. The value was left at 4700uF each as that is more than sufficient capacity given the power level of the amp. From this point on, returns on investment with further parts changing produces diminishing returns. But I did replace resistors R13, R14, R21~R24 with PRP PR9372 metal film. The resistors used in local feedback for the Op-Amp (R21& R22) can be important and they can have a direct effect on the overall sound. Vishay Dale are very good with a neutral sound but I wanted the PRPs as they are non-magnetic and designed for audio purposes. I hope this has helped!


 

 Can you tell me how does each mod improve the sound?


----------



## Tribbs

Quote: 





big sky audio said:


> I have owned a Lehmann Audio BCL for over a year. This may not be the correct place to post regarding this amp but the upgrade mod that I have performed will apply equally to the Lovely Cube clone [...]
> <snip>


 
   
  Thank you so much for taking the time to post this.  I have a LC kit still in the box and I intend to implement your recommendations.


----------



## BlaBlaBla

If you want change capacitors, avoid WIMA FKP2 at all costs. It is high quality capacitor but it is not made for audio. Especially near OPAMP... Every polystyrene (even 50 years old) kicks its ass.
   
  Only capacitor that is good for signal circuit is Wima MKP10. That capacitor behaves almost like ERO.
  Wima MKP4 I use only in places where I need more low frequencies.
  Wima MKS2 I use in power supplies.

 If OPA604 (or OPA2604) is placed in good circuit, it will blow away OPA2132/2134 and lots more expensive opamps. But OPA604/2604 is like king. It needs the best treatment and it is very picky about capacitors, resistors and circuit topology. But when it really sings - then you see the difference.
   
  OPA2132/2134 opamps are "good for everything" because they don't change character with circuit topology. You can put them in a switch power supply, geiger counter, audio device, car... You can put them even in toaster - if there is any that needs opamp. It will behave in the same way. It is easy to make circuit  (also cheaper for manufacturers) when you have opamp that likes all types of circuit. And that is what manufacturers like the most. * less expenses = more money*. Today all opamps are good enough for average listener and his demands.
   
  As far as I know (and tried) for output resistors you can use Allen Bradley or (if you can find it) Riken Ohm resistors. They have something that fills music with magic.

 Other option is Kiwame/KOA Speer. Superior details and slightly aggressive. Not so magically like Riken and Bradley, but jump ahead from stock carbon composition Dale. And many many miles away from every stock metal film/karbon film resistor.


----------



## supertrichi

Quote: 





blablabla said:


> You can find matched BC550/560 transistors but it is not worth because soldering and de-soldering them is tricky process. The best way to low down DC offset in your amplifier is to replace 1k1 resistors with trimmer pot and 1K resistor in serial connection (that will make usable range from 1K to 1K2 which is enough for voltage tuning between 14V to 16V. Also you can put there one 2K trimmer pot but that I would not recommend because voltage tuning will be less precise AND trimmer pot has deviation (usually 2%) that can make your voltages different - every time when you turn on your amplifier. You can use vertical or horizontal trimmer pot. 100R resistor leave as it is.
> 
> From my experience with LC topology I know that below 14V regulated DC voltage after regulators, DC offset on headphone out is negligible and you do not need matched transistors (BC and BD) and deviation in manufacturing process is enough tight. But when you try to use +/-18V DC and more, then matched transistors are of big importance. Unfortunately "matching transistors right on the table" is only the first part of story because when you match something that means that you need exactly the same environment for what you have matched. That means that matched transistors must always have the same temperature (transistor characteristic varies with temperature). So, it is not easy to do without custom made PCB and heat sinks. In old amplifiers that was done with 3 pin sockets that were soldered on the PCB and in there different transistors were placed and tried. When the lowest DC (or the best characteristic on the scope) was achieved transistors were soldered.


 

  
  Hi BlaBlaBla,
   
  I rebuilt my LC, following your instructions. Now it is another amp!
   
  But I have other doubts:
 If I set the same voltage  15.3 V and -15.3V with the pot, I measure a DC offset of 27mV  in a channel and - 6mV in the other one.
  There Is another way for adjust the dc offset without set  the power section, ? For example, could I put a potentiometer for each channel before of opamp or transistors in order to have indipendent setting?
   
  P.S. I can't  match the transistors. I haven't got enough components


----------



## BlaBlaBla

Quote: 





supertrichi said:


> Hi BlaBlaBla,
> 
> I rebuilt my LC, following your instructions. Now it is another amp!
> 
> ...


 
   
  You should try lowering voltages with trimpot. The lower the input voltages are - the lower DC offset will be. So try lowering your input voltages to +/-15V or even lower (around 14.5V).
  Try lowering down both voltages. But that you will be able to do only if you have two trimpots on input (one for positive and one for negative rail).
   
  For example, lower your positive rail to 15V and then - tune the negative one. If offset in each channel is still above 10mV try the same but with 14.9V. Until you get satisfied DC voltages (lower than 10mV is good, and lower than 5mV is safe for all kinds of headphones).
  I think that somewhere around 14.8-15V you will be able to equalize your DC offset. Do not worry even if you find a hot spot below 14.8V (lets say around 14.5V). In real world it doesn't matter if power stage of headphone amplifier is driven by 30V (+/-15) or by 28V (+/-14V).


----------



## supertrichi

I put a new pot instead of 1.1k resistence and I can adjust the voltage indipendent.
 But not the DC offset!
  The DC offset changes in both channel and remain near 17 mV of difference between ones.
 Indipendent if I set the positive or negative  voltage.
   
  Now I choice +15 V -14.5V and offset -8.5mV and 8 mV


----------



## BlaBlaBla

Quote: 





supertrichi said:


> I put a new pot instead of 1.1k resistence and I can adjust the voltage indipendent.
> But not the DC offset!
> The DC offset changes in both channel and remain near 17 mV of difference between ones.
> Indipendent if I set the positive or negative  voltage.
> ...


 

 It is strange...  With pots I am able to tune offset down to 1 mV. Probably transistors are from different series.

 How good is sound from the amplifier? Do you hear something unusual?


----------



## BlaBlaBla

Quote: 





proid said:


> Can you tell me how does each mod improve the sound?


 

 Whatever you do, try polystyrene as opamp coupling (10nF 63V). In combination with OPA2604 and Grado SR225 deep bass really kicks butt. Almost like sub woofer.

 With OPA2107 bass is higher but more wide, and I prefer this combination for watching movies.


----------



## supertrichi

Quote: 





blablabla said:


> It is strange...  With pots I am able to tune offset down to 1 mV. Probably transistors are from different series.
> 
> How good is sound from the amplifier? Do you hear something unusual?


 


  
  No, nothing strange.
 After changing the capacitors, following your instructions, it plays better.
 I changed also the transistors with OnSemi, unfortunately they don't match.
  it just Remains a sensation of less headstage, particularly with K701, but certainly, the basses are a little bit presence


----------



## mackat

How are these made? Doesn't Lehmann have a patent on the Cube?


----------



## nanchangbob

I read through the thread.  A lot of good information.  In the past I was more of a two channel stereo guy.  But I do have some HD600's and a self modified Creek OBH-11.  Now I took a new job and I will move to a new city.  So I will become a dedicated head-fi guy.  I need a new amp and this looks like a great project.  I'm working and living in China and I managed to work my way through Taobao and I did come across the boards used in the lovely cube. But I came across the board below and it had great feedback from the people who bought it.  So I bought it and I'm now populating the boards.
   
    The LC boards were about $4.00 and these were around $11.00, It is a little bigger so I will by a bigger case for it.  I already have a 15v *2 50 VA transformer and more than half the parts I need.  I will get the op-amps and capacitors next month when I'm visiting my family in the U.S.  The eyelets look dark in the pictures but they nice copper pads.  It even has the correct holes to install the trimmer pot.
   
   
  .
   
   
  .


----------



## marcambridge

I just recieved my LC and have to say that i was very surprised about the excellent job.
   
  Did anybody ever tried to use orange drops 715 as replacement for the yellow coupling capacitors?
  As the values are the same for the DC blocking could I use them also in that area?
  Could I use these orange drops in parallel with MKP4 2,2uF (Original was MKT 1,5uF)
   
  I replaced the low pass filter with Polystyrene caps same value.
  I saw however that Stephen used in mine ERO1838 V instead of the blue MKT.
   
  Appreciate your opinion.


----------



## liamstrain

Two questions - if anyone knows.
   
  Are the output RCA's volume controlled? or is it a pass through? and if I just want pass through, can I just bridge the wiring between the sets of RCAs or does that cause issues? 
   
  Second - could I use an external power supply instead of one of their Toroids if I were trying to save space? If so, what are the requirements?


----------



## BlaBlaBla

Quote: 





liamstrain said:


> Two questions - if anyone knows.
> 
> Are the output RCA's volume controlled? or is it a pass through? and if I just want pass through, can I just bridge the wiring between the sets of RCAs or does that cause issues?
> 
> Second - could I use an external power supply instead of one of their Toroids if I were trying to save space? If so, what are the requirements?


 
   


 Output RCA are volume controlled because everything goes through volume pot.


----------



## liamstrain

Any thoughts on this question?
   
   


> Second - could I use an external power supply instead of one of their Toroids if I were trying to save space? If so, what are the requirements?


----------



## francisdemarte

Quote: 





liamstrain said:


> Any thoughts on this question?


 
   
   
   
   
   
  15-0-15v 1A 
   
  I've also used a 18-0-18V 1A with no ill effects other than a little more heat.
   
  Toriods are usually better than most wall warts. They do sell toroid-in-a-box that look like wall warts, else hunt around ebay for "medical grade" power supplies.


----------



## BlaBlaBla

Quote: 





liamstrain said:


> Any thoughts on this question?


 
  +/- 15 V power supply. 500 mA current.
   
  You can use +/-12 V supply but output transistors will operate "closer to B class". (Now they are in high AB class).


----------



## liamstrain

thanks guys!
   
  Board and power supply are on order - "wall wart" for now - I may build a better power supply later.


----------



## kleber

The exchange of two capacitors (M-cap) in Lehmann Linear Cube SE doubles the price!!
 Valley the difference!!


----------



## majkel

kleber said:


> The exchange of two capacitors (M-cap) in Lehmann Linear Cube SE doubles the price!!
> Valley the difference!!



The best upgrade in their place is a piece of wire.


----------



## BlaBlaBla

Quote: 





majkel said:


> The best upgrade in their place is a piece of wire.


 

 Excellent. And 10 mV DC offset becomes 40-80 mV offset on output.

 I doubt that all people walk with multimeter in pocket and can always check if DAC has DC offset or not.
   
  Stay with input capacitors. MCap are excellent. Old ERO (big blue box) are very good. Losses are close to none.


----------



## majkel

Do you know any linear sources providing offset on their output? Most of them is AC coupled. BTW, offset produced by the output stage is of comparable level and there is no feedback loop in this amp to compensate it. I bypassed those big blue ERO and it showed that they weren't that excellent. When insisting on AC coupling, add a quality bipolar cap parallel to the film cap.


----------



## BlaBlaBla

Quote: 





majkel said:


> Do you know any linear sources providing offset on their output? Most of them is AC coupled. BTW, offset produced by the output stage is of comparable level and there is no feedback loop in this amp to compensate it. I bypassed those big blue ERO and it showed that they weren't that excellent. When insisting on AC coupling, add a quality bipolar cap parallel to the film cap.


 
   
  Any output source has DC offset, unless it has capacitor in series that block DC component.
  Feedback loop is not here because that involves more components and problems with ringing and oscillating if feedback loop is not made in proper way. Furthermore, if there was feedback loop, OPAMP rolling would be dangerous because LM xx, BB xx and AD xx are different speed and behave in different way so, simple said, every OPAMP needs specially tuned feedback loop for best performance.
  Output source that is made directly from OPAMP output (without buffer) involves default DC offset that is stated in tech specs plus DC offset on input (multiplied by gain). Naked out from OPAMP might be excellent choice but has two bad things. First is that you can not down DC offset with output capacitor because OPAMP does not like capacitive load (usually) and when it does, it needs additional compensation and feedback loop (more components). Second is that output resistance falls to low level (usually 50K ohm) and we all know that OPAMP in tech charts specifies minimum load when it gives specified performance (some need 1kOhm some 10 kOhm, etc..). But generally, the bigger load the better performance. In Lovely Cube (Black Cube Linear, Matrix M stage) output resistance (what buffer sees) is 10 Ohm which is high and can be lower to 2.2 Ohm with changes in resistance (1.5 kOhm resistor to 2.5 kOhm) but it will make amplifier prone to oscillation and OPAMP rolling will not be so easy. Current through BC 550/560 transistors will be lower and ratio between BC/BD transistor current will be higher - reason for oscillation - needs better noise control and source and tightly matched transistors.
 The most important thing is what kind of load sees OPAMP now (with bufFer). it sees almost pure resistive load (buffer) and its (buffer) resistance is close to 160 kOhm. 160 kOhm is enough for every OPAMP to behave within specs. Only reason what people see difference between diamond buffer and naked OPAMP out - is in load resistance. A pure technical reason without voodoo magic.
 After I researched few things and make few Lovely Cube amplifiers I fount out something what makes me laugh. And that is - biasing OPAMP in A class. If we want to bias something in A class we need DC current through buffer, OPAMP or output stage or middle stage. Whatever... Our case - BJT transistor, that will always be in ON state and in area where BJT transistor behaves like amplifier (most important thing!). If we want to bias OPAMP in A class it is almost like we drive voltage amplifier (preamp) in A class. If OPAMP must drive 160 kOhm load then how much it needs to be driven in A class? Well, it needs only 40-80 uA. Improvement that people see when they connect 5 kOhm resistor between OPAMP out and negative rail is just opposite (downgrade) because it involves two things: noise from supply source directly to OPAMP out, and low resistance (OPAMP now must handle higher current where 98% represents pure heating and buffer becomes useless).
   
  When high resistance buffer is in output stage (represents current source), biasing OPAMP in A class with DC current more than 200 uA is total nonsense.


----------



## majkel

Most sources have capacitors in series and that's why you don't need another. If you care so much for the offset matching then remove 10k resistor in series with these capacitors before the op-amp input and place there something matched (depending on the op-amp) and remove the 100pF capacitors to ground. I've got the MSc degree in Electronics Engineering and I don't need explanation what is the difference between open loop and close loop buffers. I I've been modding this kind of amps since more than three years, different flavors of the BCL circuit. Biasing modern op-amps into class A is obviously stupid and there is more bad things about it than good, including distortions. The easiest protection from capacitive loads are series resistors. No more than 75 ohms will work but it's not necessary here as much as capacitors in series anywhere else. 

I mentioned the open loop discrete buffer because it's never compensated thermally enough to justify strong fight for stringent offset numbers anywhere else in the circuit. 40mV is pretty normal and either you match the transistors and resistors in the buffer (good for people having much time to spend on it) or you accept it and don't care for another couple of mV appearing somewhere else. 

BTW, the output impedance of the diamond buffer is 5 ohms, not 10 (as you read from the resistors) and I would leave it as it is.


----------



## BlaBlaBla

I would not remove 10k resistors because ALPS pot has always the same resistance but not on OPAMP side. It has always 50k on source side. On OPAMP side there is variation between 50 kOhm and 0 kOhm. So if I remove 10k resistor, when volume is close to maximum, I will get 50k resistance to ground (through volume pot). When pot is close to zero I will get 0 ohm to ground at input.
 100 pF capacitor acts as filter that blocks frequency (- 3dB) over 25 kHz (when pot is close to zero) and 160 kHz when volume is at maximum. So here, lots of things are hovering around and in this case it is hard to optimize input signal for opamp because it depends on volume pot that changes entire characteristic (frequency with 100pF capacitor, and resistance). If I remove capacitor then I have to place 100 kOhm resistor on its place but with that I get nothing special because of potentiometer (50 k). I changed 100 pF capacitor with 51 pF and that changed magnitude and phase little bit. Which is good because attenuation is less but not so good because opamp might start to oscillate. Frequency range of input filter now goes from 52 kHz to 310 kHz.

 It really does not matter if it is 5 or 10 ohm because Grado needs 4 ohm to be properly damped, and Denon needs 2-3 Ohm. The lower the better. There is no problem if that resistance falls below 2 ohm. Problem is in heating because design of heatsinks can not handle so much heat. Heat goes up if I leave 1.5k resistors in BD circuit in the same time as output resistance falls to 2 ohm. That lifts DC current from 35 mA to 150 mA. And that current represents A class biasing.
 Btw. stock LC buffer works in AB class (35 mA) when volume pot goes over 1/2 and amplifier drives low impedance headphones (Grado, Denon).
   
  I am not so educated. I work as gigolo in local club. Between two chicks I mess with electronics. Girls like that.


----------



## majkel

My Grado sound best a bit above 5 ohms and 6 ohms is maximum. More makes them too bassy, however I'm talking about a completely different amp. Regarding the ceramic lowpass capacitors, as you mentioned, their filtering point is floating with volume anyway and the resistors allow to narrow the bandwidth swing but actually you can remove them and most op-amps will remain stable.


----------



## kleber

ok, ok, but, but,

 lehamann liner cube costs € 775 and
 lehamann liner cube SE costs € 1420

 Justified?


----------



## sobol

Maybe someone can help me. I've bought a kit, soldered it, then turn it on and... it works. But. A DC offset on output was about 200mV on a first channel, and 5V on the second channel. I've checked opamps Vcc and it also wasn't correct. So i've resoldered a "power" section of the BCL and there is still a problem. Resistors after a rectifier bridge (two 4,7 ohm parrallely conected, to sets, one for + and for -) burn after i turn the power on. Also the diode which signals "power on" does not work. Does someone have any idea what is wrong?


----------



## liamstrain

Could be a diode in the wrong direction?


----------



## sobol

No, it worked before resoldering the power section.


----------



## francisdemarte

Quote: 





liamstrain said:


> Could be a diode in the wrong direction?


 
   
  I am inclined to agree. Double check the polarities of all your components, something is on backword or there maybe a short/bad soldier joint someplace.


----------



## francisdemarte

Here's a tip from Stephen one of the ebay sellers of the Lovely Cube board.
 Which reminds me. Make sure your input is AC!
  



> In these 2 days I saw someone has problem in soldering kit.  I guess the problem may be the wrong wiring of AC input as 15V-15V-0.  It should be 15V-0-15V.  Since I am not the member of headfi forum, would you mind to post this possibility of problem to see whether it helps.
> 
> Thank you again for your contribution in this forum.
> 
> ...


----------



## sobol

Lm317 was dead. Now all works. I had some problems with a huge offset (about 200mV) on the output, but I've reduced it with a trimpot to about 10mV. Now the most annoying thing is hum. It's quite loud and in my opinion its caused by a pot and resistors (poor chinese quality like all parts - a kit from ebay). In future I'll change nearly whole parts for some good quality parts.
  However, the sound is awesome, even with this parts, and its totally worth to buy it.


----------



## liamstrain

Make sure your pot and such are all grounded well - even if you have to run another wire from the casing (if metal).


----------



## sobol

Everything is grounded well and hum is still there. Nevermind, I'll try to do something with it.


----------



## BlaBlaBla

200mV DC offset? There is not chance that properly soldered parts would give you such big offset. Even if transistors are completely different. You did something wrong and you must check connections again. Parts can't be so bad.

 The highest offset that I saw once, was with combination of different BC and 2N transistors together - and it was 40 mV!


----------



## sobol

I guess different voltages on R3/R4 and R5/R6 are a prove that something is wrong in the circuit. Am I right? These voltages were measured with desoldered lm317 and lm337. Voltages are different also on the inputs of lm's. I'm waiting for rectifier diodes and filter capacitors to change them - though multimeter says that diodes are ok, I'll change them, just for sure.


----------



## prairiemystic

What is typical output stage bias current? I got the Yuanjing Lehmann clone (from eBay) and just started digging into it.
  Rails are +/-16.7VDC and 53mA bias current; heatsinks are running 70°C which seems a bit too toasty. I could lower the rails to +/-15VDC or ?


----------



## prairiemystic

Lowering rails from 16.7 to 15VDC, a few mA less bias, Vregs a little warmer but still a finger burner.


----------



## headfinn

Hello Everyone,
   
  I just had to create a username to thank everyone (especially BlaBlaBla) who has shared their knowledge in electronics and contributed to this great thread. About a year ago I implemented almost all of the mods mentioned in this thread successfully and it was really interesting project that taught me a LOT about electronics. Prior to this I had practically no electronics experiense beyond school physics (and that was a while ago .
   
  To the discussion about the DC-offset I would like to add that I found out the hard way that you should make sure that the BC550 and BC560 transistors are from the same manufacturer and/or have same but opposite "Base−Emitter On Voltage" (for example ONSEMI -0,62V and +0,62V). To my understanding because of the push-pull operating principle, difference here contributes directly to the DC-offset.
   
  Also, one interesting thing I would like to mention is that when doing some RMAA measurements with EMU 0404 USB, I found out that all of the above zero gain modes gave worse noise-level results than the zero-gain setting. My own assesment is that by enabling gain you also insert ground connection to the OPA feedback loop and it picks up some noise from there. I think the original BCL could be better in this regard because it uses high quality custom toroidal transformer which has a ground connector and I guess it has some sort of a grounded electrostatic shield between primary and secondary to suppress noise.
   
  And thanks again for everyone.


----------



## vinodt1347

Hi,
  Please check the link below
  http://www.ebay.co.uk/itm/200723854874?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649
   
  This seems very similar. Thoughts on buying this with a view to change the components. LC is 3 times the cost.


----------



## Nixon

Similar one here as well http://www.ebay.co.uk/itm/YJ-lehmann-headphone-amplifier-BD139-BD140-LM833-/190651055620?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item2c63b03e04


----------



## Diseree

Building quality of Lovery Cube is great, but I can hear slight hum noise anyway when I use low-Z and high sensitivity headphones.
  It may be designed for middle-Z or hi-Z headphones.


----------



## jimbomak

Have built a clone recently and am enjoying the sound although my Graham Slee Novo beats it. Will have to change some of the components to see if it will sound better.


----------



## nippon

hi,
  i have build a diy kit from ebay and get a bad DC Offset 200mV on the Headphone-jack.
 Most of the parts from the Kit i have changed against matched Transistors and so one (caps, elkos...).
 But here is my Question:

 Behind the AC15V-0V-AC15V i have measured the V and my multimeter said on one side of the Diodes there are +21V and on the other side -17V
 The DC Output to Opamp is +14,4V and - 14,5V
 and the DC out is about + 14,9V and - 14,7V
 The LM337 Output is 14,7V
 And the LM317 Output is 14,9V

 Maybe the LM337 and LM317 are producing the 200mV DC offset?
 Or could it be the "energy section" with the diodes and the +21V and -17V readings?

 Greetings from berlin

 PS: i'm using a quality 1A 2x15V ring trafo!
  
  http://bilder.hifi-forum.de/medium/26674/img-20130131-00549_264128.jpg
   
  Edit: Offset was only bad in left channel because of bad BC550C/560C pair. Now everything is fine execpt the hum. Will work on that issue.


----------



## Comfortable

My lovely cube has a buzz when turned on, only heard through headphones. It does not play music. I have no idea how to fix it, so I kept it in storage for 3 years.
   
  I need money quickly, here I am selling it.
   
  http://head-fi.org/t/653920/lovely-cube


----------



## vintageaxeman

*Modifying a Lovely Cube to take it close to the Lehmann SE version.....*
   
_*Briefly...I have taken a Lovely Cube, replaced some parts, built an outer case and made my own version of a LEHMANN AUDIO BLACK CUBE LINEAR SE headphone amp.*_
   
  On the Lehmann website, the SE version details are as follows:
   

 _Power Supply Caps:_ _Mundorf MLytic_ _Signal Capacitors:_ _Mundorf MCap_ _Internal Cabling:_
_Feet:_
_Fuse:_
 _Mogami Neglex_
_SSC vibration absorbing feet_
_AHP Fuse_
   

  Right!
   
  I bought a Lovely Cube which had been assembled by someone else, from 'a well known auction site', and when it arrived, it sounded VERY good. I could not believe that on this clone, even the circuit board said LEHMANN, and the front panel, instead of being printed with the words 'LOVELY CUBE', actually said Lehmann Audio Black Cube Linear'. Naughty....   It sounded excellent with my HD650s and my Beyer T1s...
   
  However, I had been reading about the SE changes that Lehmann had used in their latest version, and thought that I'd have a go at modding it.....
  The changes I made were:
  1. Replace the 2 Power supply caps with Mundorff AG Electrolytics.
  2. Replace the 6 capacitors at the front of the main board with larger Panasonic FC types.
  3. Replace the input caps with the same ones that Lehmann uses: Mundorff 2.2uF polypropylenes.
  4. I also decided to upgrade the Toroidal transformer to a higher VA. I changed it from a 30VA to a 60VA. The original Lehmann and Lovely Cube ones are 15-0-15s. However, my Lovely Cube had arrived with a 18-0-18 transformer, so I decided to stick with that voltage. I JUST managed to cram it in!
  5. I also replaced the input cables with Mogami Neglex Quad microphone cable, which is similar to that which Lehmann use on the SE.
  6. I tried an OPA2111AM IC and loved it, but I thought I could go one better. I put in a Class A resistor Bias board. That helped! Then I thought why not reduce crosstalk even further by using MONO chips, the OPA111AM on a Stereo to Mono board. The result is in the pics.
  7. Out of sight, I put a pure silver audio fuse, hidden away in the fuseholder, just like Lehmann do....
  8. Under the circuit board, I bypassed the 2 main capacitors with 2 small polystyrene caps.
  9. I used car sound deadening panels to help deaden the main metal panels of the casing.
  10. I made an outer case out of perspex (acrylic) sheet 3mm thick. I have access to a laser cutter, so this was easy. Lehmann use an extruded aluminium outer case, veneered, so I veneered my acrylic on the top and sides with genuine Santos Rosewood. I used a cabinet scraper to get it smooth, and then gave it 2 thin coats of finish.
  11. I masked the case and spray painted the inside of the case front silver.
  12. I bought some SSC feet, the same ones that Lehmann use on their SE, and fitted those.
  13. The inner case is fitted to the outer case using the ORIGINAL bolts which had held the original rubber feet.
   
  What do you reckon? 
   

  The first pic is of the beautiful, genuine, Lehmann SE headphone amp range....
  And below, its innards....
   

   
   
  And here is my home-made, not for profit own version....
   
  Santos Rosewood veneered casing...
   

  ...have to fix those scratches on the silver interior....
   

  ...you can see the edge of the black acrylic casing...
   

  SSC isolation feet...
   

  ...outer casing (above in pic) and main casing (below) separated for clarity...
  the black 'mesh appearance material is self adhesive damping material for car panels...
   

  ...ditto...
   

  2 Mundorff Electrolytics, 2 Mundorff M-cap polypropylenes, larger transformer and Mogami Neglex Quad cable...
  On the underside of the circuit board there are several high quality high tolerance polystyrene capacitors in parallel with all the electrolytics.
  ALSO....If you look at the edge of the transformer, there appears to be a grey line round it. This is an RFI/EMI shield.
  I bought the material which is a tight weave plastic coated material and formed it into a tube which fits neatly over the transformer,
  I don't know if it helps but I doubt it does much harm!
   

  6 Panasonic FC capacitors, and the dual mono IC board with 2 OPA111AM chips, sitting atop a Class A BIAS adaptor...
   

  Clearer view of the dual mono IC and Class A adaptor underneath...
   

  Mogami Neglex Quad cable. This is REALLY good cable!
   
  The changes have REALLY opened up the sound.....cymbals shimmer and bass notes are clearer but feel deeper... separation between instruments and voices is more naturally pronounced, but most importantly, the Pace and the sense of people playing together is there. It almost sounds as if the players are more professional, because the sound, whilst clearer, is more coherent.
   
  Now I need to look at a few other issues....
  The next thing I want to look at is the output transistors, the BD139 and BD140. I have a load of genuine Philips BD140-16s, but no BD139s. I have loads of non-Philips stuff, but if anyone has any Philips BD139-16s, I will willingly swap some Philips BD140-16s for them....
  Then there's the other elec components....not sure which to change as a priority...any suggestions, guys?


----------



## jimbo27

waiting for my cube clone circuit board to arrive, cannot figure out how I could put in those mundorfs and still have those square red capacitors also, have checked the board on the lovely cube website.


----------



## Greenleaf7

Quote: 





vintageaxeman said:


> *Modifying a Lovely Cube to take it close to the Lehmann SE version.....*
> 
> I have taken a Lovely Cube, replaced some parts, built an outer case and made my own version of a LEHMANN AUDIO BLACK CUBE LINEAR SE headphone amp.
> 
> ...


 
  Love the design. Aesthetically simple and classy! great work there


----------



## vintageaxeman

Thank you for your appreciative comment!


----------



## timjar

_I am also starting to build one_


----------



## vintageaxeman

Let me know if you want any advice about parts or building, etc....


----------



## timjar

Many thanks for the offer, so glad to see someone who does not replace input capacitors with a piece of wire, already wondering if you can buy  Mogami Neglex cable by the metre.


----------



## vintageaxeman

Mogami Neglex QUAD cable IS available on the net. My transformer was from a certain auction site, and HifiCollective are great for caps. Stephen at Lovely Cube is VERY helpful and gives great advice. The dual mono IC board was also a Buy It Now...about £3 I think.
   
  Get the cable in the UK here:
   
  http://www.hhb.co.uk/product_list.php?section=124
   
  I bought 6 used patch cables with stereo 1/4" jacks for very little and sacrificed one of them for the cause!


----------



## timjar

Quite pleased I have found the enclosure for sale on Alibaba, as Stephen will not sell it on it's own.
   All the enclosures on Ebay that are large enough are just a little too spacious.
  looked at that Mogami Neglex cannot believe it is less than 5mm diameter, your photo is so deceptive, also looked at the cable on Hificollective site, can hardly believe the price of some of them.
  Still compiling the list of parts I need at the moment with the help of BlaBlaBla


----------



## vintageaxeman

Quote: 





timjar said:


> Quite pleased I have found the enclosure for sale on Alibaba, as Stephen will not sell it on it's own.
> All the enclosures on Ebay that are large enough are just a little too spacious.
> looked at that Mogami Neglex cannot believe it is less than 5mm diameter, your photo is so deceptive, also looked at the cable on Hificollective site, can hardly believe the price of some of them.
> Still compiling the list of parts I need at the moment with the help of BlaBlaBla


 
  Timjar, if you are in the UK, I will send you some of the Mogami I used...and you are correct, the cable is around 5-6mm diameter. The cable used in the Lehmann SE version is Mogami, but it's not the Quad cable I used, which has 4 cores, twisted together, so provides some RFI rejection. I have some spare and can send you enough for the job free of charge if you IM your address to me.


----------



## vintageaxeman

Can you send me a link to the Alibaba page where you found the enclosure, please?


----------



## timjar

I have already emailed to check if a black front panel is available, but unfortunately it is not.  http://www.aliexpress.com/item/DIY-Headphone-amplifier-case-amp-chassis-enclosure-JR001/578840933.html


----------



## vintageaxeman

I was lucky. The clone I bought, which I am still modding, was built in Hong Kong by a guy who had made several....and he had been naughty enough to even copy the official logo onto the front panel. Even the circuit board had 'apparently' proper markings...
  But although it was very good, the mods that are outlined in Head-fi, and the mods I have decided to do, have pushed it ito a different league altogether.
  I use Grado PS-1s, Beyer T1s, Sennheiser HD650s and....Sony MDR-XB500s...cheap but really quite good! (although I have an ongoing 'beef' with Sony so I generally avoid their products...   )


----------



## vintageaxeman

Quote: 





timjar said:


> I have already emailed to check if a black front panel is available, but unfortunately it is not.  http://www.aliexpress.com/item/DIY-Headphone-amplifier-case-amp-chassis-enclosure-JR001/578840933.html


 
  Yeah, it's not brill, is it!


----------



## timjar

I think the front panel doesn't look too good in the one photo because of the lighting.


----------



## vintageaxeman

it just looks a bit roughly ground on the edges....
  Of course, if you are planning an SE version with an outer case 'like wot I done', then the inner case does not matter too much as long as it shields the amp....so you could get away with a specially designed front panel.....you have any DIY skills or know anyone who can cut/bend sheet metal, etc? The front panel could be made out of 6mm perspex, laser cut, or brass, chrome plated, etc....world's your oyster, really! Especially if you live in an area where there are little traditional machine shops in the backstreets....


----------



## Faithless

Hello guys...

 I  bought a Lovely Cube a few months ago.

 After many OPAMPs changes...
 I found a *HUGE* improvement using the *AUDIO-GD OPA-Earth.*
 It need a extension cord for fitting it inside the case (Cap Type - about 150-200mm).
  http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm
   
  There was an noticeable improvement in the sound extension.
 More defined bass and treble.
 More natural and spatial sounds.
  Just great !!!

 I will take some pictures soon...


----------



## jimbomak

My first attempt at building a clone. Sounds good and hardly use my Graham Slee Novo now. Top picture is the bare board. Board £25. Chassis £40. Transformer £20. Alps pot £10.


----------



## jimbomak

My Clone and Graham Slee Novo. Might have to tweak it a little bit. Already replaced clone volume control with an Alps and input capacitors with [size=small]2.2uF 400V MKP Polypropylene film capacitors[/size] . Also replaced op amp that came with it for an [size=small]OPA2604AP. Myself and my friend prefer the clone to the Novo. Use Audio Technica ATH AD700 and Grado SR325 headphones on these.[/size]


----------



## algar_emi

Ictmanganer you have mail. I want to discuss parts choice.Thanks...
  Algar_emi


----------



## staxPatrick

I completely removed the power supply from my headphone amplifier. I built a Lt1083 regulated +-15v power supply  to power the amp. here are pictures. I haven't hooked it up as yet. The transformer is 80VA, dual 18V secondaries. Filter caps., 10,000uF, dual bridge discrete diodes. I will post updates when I get time to do some more work on the unit.
 . 
  

  

  

  
  I've finally finished the power supply and amplifier.  The new power supply took the amplifier to a different lever of performance. I removed all the power supply parts from the original design. I don't really like the sound of LM3xx regulators, too harsh and noisy. 

  

  


 Don't expect miracles by just replacing passive components. The heart of every audio system is the power supply, so that's why I spent so much time building the best sounding power supply for the amp. The improvements especially in the bass areas are nothing short of subwoofer quality deep and controlled. Music comes out of a dark silent background with authority and fullness. The power supply is fully adjustable and is very stable and runs very cool.
  
 Additional changes that I made to the amp are input caps are polypropylene in oil, power rail caps are Panasonic FM 680uF and 470uF bypassed with .1uf, silver mica caps input to ground on op amp. I will roll op amps to hear what suits me best. I also replaced the phone sockets with Neutrik gold plated. My objective is to  address areas that make the most significant difference in sound.
  
 I'll probably sell this amp and move on to the next project. If you have questions, just email me.
  

Reply


----------



## sunneebear

That is one serious first post.  Very nice work.


----------



## Danielsc

Hello to all..
  This is my ever first post on a forum..
 But it is now more than one year I red every post of this thread.
  I managed to build a "personnal" clone of the Lehmann..
 I used all excellent components.. PRP résistors, Siemens styroflex, Mundorf caps, Panasonics, .. LME49720HA opa..
 I Think I reached a top of quality.. It sounds very, very good with my Sennheisers HD 600..
   
  I tried to post a picture.. but system says there is a communication problem with the server..
  I 'll try later..


----------



## Carlitos

can you convert the lovely cube to "dual mono"?


----------



## liamstrain

Quote: 





carlitos said:


> can you convert the lovely cube to "dual mono"?


 
  Convert? Not that I know of - You could do full balanced by building two of them in one casing.


----------



## Carlitos

ok thankss!  so no "lovely matrix quattro cube" for me


----------



## MrTechAgent

Its Engineering after all


----------



## Danielsc

Hello..
  Can you maybe tell me how to post pictures while replying?
 I get no form when I click on the "insert image" icon..
 Can it be because I've IE10?
   
  Regards.
  Daniel


----------



## MrTechAgent

Quote: 





danielsc said:


> Hello..
> Can you maybe tell me how to post pictures while replying?
> I get no form when I click on the "insert image" icon..
> Can it be because I've IE10?
> ...


 
  It is because of your post count , once you go over 30-40 you will be able to post pics


----------



## Danielsc

Hy..
 Ok..
 I will then put some posts..
 Trying to be interesting for everybody..
   
  Regards.


----------



## Danielsc

Quote: 





francisdemarte said:


> Someone was kind enough to provide a link to this amp on ebay in the Matrix M-Stage thread. I thought I would be a great amp around 1/2 the price of the M-Stage and an easy DIY project to pass the time.
> 
> 
> 
> ...


 
   
  I made almost every mod that are described here..
  I did not Bypass the input caps but used MKP Mcaps.. I use 6N wire for the kabling to the RCA sockets.
  But, about the OPA, I choosed the OPA2111AM.. I tried the KP model, but was disapointed by it.. But, this is probably a personal taste..


----------



## Chodi

I was actually thinking of ordering one of these Lovely Cube premium version but when I went to his web site today to get a quote I found that none of the contact links are working? I was unable to leave a request for quote? Is he out of business? Then I looked on Ebay and I find that the finished Lovely Cube is not there (at least not today). I will try to send him a note later through his Ebay site as he has a few items listed but this is not encouraging.


----------



## Dillweed

I just e-mailed him yesterday about a question I had for the pre-assembled Premium I bought from him back around Christmas of 2011, and he got back to me within the day. You might want to try just e-mailing him if you haven't already. I don't know if he's still making these or not since I didn't ask, but he's still reachable in any case.


----------



## Danielsc

Hello StaxPatrick. I'm very interested in this project, with the power supply apart. I just wanted to know what was then needed to disable, on the amp PCB? Upto wich part? Do you have some pictures to show, already? And what are the results of modding it this way? Regards.


----------



## linhhonlangdu

Hi guys, I have just made a Lovely Cube. I am trying IC OPA627AO but not sure about its quality. Would you please give me some recomendations? Thank you.


----------



## Danielsc

Hello..
  Good evening from Belgium..
  There are some posts about the different OPA's, in the first pages, I think.
  Changing an OPA is the easiest way to change the sound of your amp..
  But be sure that you are the only one to know wich will fit the best to you. It is only a mather of personnal taste.
  Basic OPA will probably not be the end choices. They are cheap, they work, and that's all.
  I like the détails and airy sound.. So, my choice went to the OPA2111AM. Very clear, very detailled, and a very wide soundstage.
  Just after this, I would choose the LME49720HA.. I did not try yet, the Dual LME49710HA, but I heard very good feedback from it.
  I got the dual OPA627AP, but it is not very precise in the deep bass.. It has very good mids, but not enough clarity in treble and low basses..
  These are only some I tryed.. There are lots more.. If you can affoard, try Discrete OPA..
  But, be sure the only one who gets the best answer is yourself..
  Regards.
 Daniel


----------



## linhhonlangdu

My lovely cube has some problems.There are hum sound when the volumn is up to more than 30% loud.Does anyone know the reason and resolution for this problem?


----------



## Danielsc

Hello.
 Did you make some mods on your LC?
 Or is this hum present since you got it?
  
 Regards


----------



## linhhonlangdu

I got the "hum" sound right after i made my LC ( I haven't moderate it). When the volume is over 50%, the "hum" sound appear (Even if there is no input signal).


----------



## nippon

Hi,
 a few questions:
  
 Have you connected the Alps poti to GND/Case?
 How big is your DC offset?
 What headphones do you use while the "hum" appears?
 High sensitive phones will make the hum audible, try to keep in mind that every amp hums, just with a different intensity.
  
 For example: On my LC clone i can't use the AKG450 or the Audio Technica ATH-M50, but AKG K601 and DT 770 (250ohm) are nearly silent.
 But my Clone works no longer in class A mode. If you are willing to modify you LC with a soldering iron i can give you some tips, just let me know (if you can read german i can send you a link to my "how to fix/build an LC clone" thread)
  
 regards,
 nippon


----------



## Danielsc

Hello, Nippon..
  
 Greatings from Belgium.
 You can always send the link, even in german.. It can always be interesting, even if sometimes, Google traduction have to help .
  
 Regards.

 Daniel


----------



## nippon

Well, here is the link. May google be with you 
  
 http://www.hifi-forum.de/viewthread-71-10591.html


----------



## HumanSaurusRex

Can someone please do a little comparison between the lovely cube and other DIY amps like the O2?
 I need a new DAC/amp combo and can't decide whether to go O2/ODAC, Magni/Modi, pupDAC/Lovely Cube, ...
  
  
  
 Thanks for your advice!


----------



## linhhonlangdu

nippon said:


> Hi,
> a few questions:
> 
> Have you connected the Alps poti to GND/Case?
> ...


 
  
 Hi everyone
 I have read your link with the help of google and I think my problem lies in the quality of the components, but I'm not sure 
 I have connected the Alps poti to GND/Case,it was better but still not completely discharged hum
 I used the ATH AD900 while the "hum" appears, I tried with the others, but all are the same
 Finally, I don't know the concept of "DC offset", can u guide me ?
 Thanks


----------



## nippon

Hi!
  
 You need a DMM - "Digital Multimeter". Use the mode for 200mV or 20mV and use the red and black "chopsticks" to read the... let me call it _failure rating _(DC Offset) of the Output_._
 Here is a good "how to" on this website, but for speaker amps ->  http://www.wikihow.com/Measure-DC-Offset
 For Headphone amps is nearly the same:
  
*Open the case for measurements and put one test lead to the phone output. In case you don't know the connection of a phone connector ->
  

 Tip (close to the heatsinks)
Ring 1 Ring 2 (close to the front)
Left ChannelRight ChannelGND
  
 So measure this:
 between ring 2 and ring 1
 between ring 2 and tip
  
 0mV is very good < less than 50mV is fair but ok < more than 51mV is bad < when there is a offset bigger than 100mV, do yourself a favor and don't connect such expensive phones like the audio technica. They may take damage.
 You did not solder the LC by yourself, do you?
  
* if you never opened an electronic device before, please be careful or ask someone who has experience. Inside the LC are some voltages, that can hurt and close to the transformer (the round thing) is enough voltage for very serious injuries! Every device powered by a wall outlet can be dangerous, when you open it!!!
 Also don't start to put test leads everywhere just for fun, i did that when i started in DIY. Some components may take damage if you create bridges for the voltage with your DMM.
  
 kind regards!
  
 PS: The quality of components... that is a very large topic on a headphone amp. Best way to solve a problem is to find the reason. Check the DC offset, then we will go further 
  
(edit: it was late and my mind spoke german to me  )


----------



## linhhonlangdu

Hi,
 Thank you very much, nippon !
 I checked the DC off set , it's less than 50mV
 I bought the kit on ebay, components originating from China, that may be the problem ?
 although I do not use more than 50% volume, but if i use the gain, the hum destroy everything 
	

	
	
		
		

		
			




  
 kind regards!


----------



## nippon

Hi,
 you're welcome!
 I'm glad that i maybe can help someone to achieve a better sound quality and i know your situation 
 So you bought a kit, that means you solder it yourself?
  
 You should try to imagine how this circuit is working.
 There is a power supply -> delivering 2x 15V via 1xLM317/1xLM337
 First the audio signal reaches the OPA, and from there it is amplified at the NPN & PNP transistors (BC550/560 & BD139/BD140)
 When we find the spot which makes the hum noises we can possibly improve that area.
 Search for the datasheets of all that components (LM317,LM...,BC550,...BD140)
  
 Well, let's measure some more points:
Power Supply:
 The voltage of the powersupply should be nearly the same. Are there really around 15V getting to the OPA and the transistors?
 (in my opinion the LM317/LM337 is a good voltage regulator but not the quietest)
  
Audio section:
 First check the OPA. Identify the model and find the datasheet.
 Is he getting enough current?
 Is there a DC offset on it's 2x outputs? (measure between "out A" and " -In A" , 20mV on the DMM)
 Is it very hot after the amp is running for quite a while?
  
 Afterwards you can compare the measurements of the transistor pairs. Just let me say, there is a large space between a working and a not working transistor. High quality audio products got matched transistors to prevent the signal from getting interfered. (i hope there are some experienced guys reading my reply & correct me if i'm wrong   )
 We're searching not for some differences of 4%, we're looking for a big imbalance.
  
 If so far the voltage is ok, the OPA is ok and the transistors are working correctly, you can try to add a feedback modification.
  
 Keep in mind, that is a big circle of components and the audio signal is influenced by all of them.
 When you bought a very cheap kit from ebay, than you will get parts that work together but there is no internal harmony.
 IMO that is one of the reasons why the Matrix M-Stage and the Lovely Cube are more expensive.
 And of course maybe you got super sensitive ears 
  
  
 kind regards
 nippon


----------



## forumfan

linhhonlangdu,
  
 when you switch the power off on your cube do both the leds go off at the same rate, as I had the dreaded hum on my cube, but mine is built with quality parts, one led fades in less than 2 seconds and the other more than 5, I have checked the soldering under the board over and over,shaking the board, proding all the components.
   I was checking the offset for the first time Today, and rather miraculously the hum disappeared,  now both leds also fade at exactly the same rate.
     hopefully the hum will never return.


----------



## nippon

forumfan said:


> linhhonlangdu,
> 
> when you switch the power off on your cube do both the leds go off at the same rate, as I had the dreaded hum on my cube, but mine is built with quality parts, one led fades in less than 2 seconds and the other more than 5, I have checked the soldering under the board over and over,shaking the board, proding all the components.
> I was checking the offset for the first time Today, and rather miraculously the hum disappeared,  now both leds also fade at exactly the same rate.
> hopefully the hum will never return.


 
  
 Hi forumfan,
  
 the leds are also a little mysterious on my LC clone. When i switch my power on, they are starting to glow in balance, but if i'm power off the amp one led glows maybe 1,5 seconds longer. I asked in my thread (hifi-forum) about it and the people were assuming that there is nothing to worry about it. Both leds are getting the same amount of current and it should only be a matter of how fast the power fades away (depending on how slow the LM317/LM337 are reacting on the "power off").
 But there is something i would like to ask you guys:
  
 I measured this results in my power supply (picture) -> can you please measure these points on your LCs?
 The point is that there is a difference between the DC 20,7V and the 17,8V - using a 2x15V AC transformer.
 (My DC voltage is now equal because i installed 2x resistor trimmers (not in the picture) so that i got now DC 2x 15V instead of 14,9V/14,7V for the circuit)

  
 kind regards
 nippon


----------



## linhhonlangdu

Hi everyone,
 When i switch the power off on my cube do both the leds go off at the same rate
 I have measured all points in the direction of nippon ( again, thank you very much ) everything is at an acceptable level, so I've replaced a few componen ( I have replaced the capacitor 470uF ) 
 My LC was bettter ! 
 After this time, my experience is: quality of components is very important for sound quality
 Thank you very very much !


----------



## forumfan

Hi Nippon,
   I am using a 2 x 15 volt transformer and I get  AC values of 18.5 for both and DC 23.3 for both at the points you specify.
  
                                                                           Regards,
  
                                                                                              Forumfan


----------



## akms

If anyone has a technical eye, can they tell me which of the following clones has the better components? My friend in the south east says he can get these models for me but they vary in cost. Obviously I don't have the technical know how to see which models are better value. Any help would be appreciated.
  
 Just for comparison here is the original laser collection lovely cube:
  




  
 Option A:




  
 Option B:
  




  
 Option C:
  




  
 Option D:


----------



## forumfan

Hi akms,
   the problem is whether or not the parts are actually genuine, but I would discount B as I don't like the look of those large silver capacitors, they are certainly not a desirable brand.  It really is worthwhile buying the board and going through this thread to select your own parts, the extra cost in my opinion is really worth it.


----------



## nippon

Yes, i agree with forumfan.
 Buying the PCB or a kit that contains it, gives you the option to check and change all parts. If you are not interested in DIY, just spend more money on the Lovely Cube or the Matrix M-Stage.
  
 Every picture of your A - D variants has some good and some bad things on it. Once i bought a kit for 30€ and thought that would be a great deal. 60 days later i invested about 70€ more to get a result i like today.


----------



## akms

Thanks for the replies. I saw that the lovely cube is around $230, but these models are all below $150 fully assembled. I'm not technical enough to choose and swap components so I'll guess I'll read a bit deeper into it before making a decision.

Also does anyone know what these are like paired with Beyedynamic DT880 600ohm and Fostex T50RP?


----------



## taiyoyuden

My right channel recently started having problems. The volume is low and sound is distorted/weak. I tested the DAC and headphones without the amp and they work fine. Anyone know which amp component might be failing?


----------



## forumfan

If your Op amp plugs into a socket you could try giving that a little poke as I have had a similar problem when my Op amp was not pushed home in the socket fully, it could just be a bad connection elsewhere, the input cable connections are another likely possibility.


----------



## taiyoyuden

Thanks! I pushed the opamp down some and it's working now.


----------



## nanchangbob

Hi Patrick,
  
 I like the thought of using an alternative  to the 317 and 337 regulators.  I think the LT1083 is a positive regulator?  Wouldn't you need one side to be a LT3015?
  
  I will be heading to the U.S. next month to visit family and I have a set of Salas BIB low voltage shunt regulator boards from DIY audio waiting for me.  I might try the same thing with those.  Anyway if I'm wrong about the 1083 let me know.
  
 Thanks,
 Bob


----------



## Shaffer

I own Option-B. Here are my impressions:
http://www.head-fi.org/t/642103/oppo-bdp-105-headphone-amp/15#post_9866530


----------



## linhhonlangdu

Hi nippon,
 How are you ? It's me again ^^ 
 I want to ask you 2 issues:

 1, Can replace BD 139 and BD 140 in the other?

 2, Is Matrix M-Stage is another clone version of the LC?

  
 kind regards!


----------



## nippon

Hi linhhonlangdu, i'm fine 
  
 You can't swap the transistors with each other. The BD139 is a NPN and the BD140 is a PNP transistor & changing them will possibly cause a short circuit  !DANGER! 
  
 And the other question... yes, they are using nearly the same circuit. But as you know, you can buy a 100$ "no name Clone", a 225$ Lovely Cube, a 225+$ M-stage or a original Lehmann Linear for over 700+$. Just imagine how big the chance is, that the clones are at the same or a better quality level. So my second answer is also -> no 
  
 kind regards,
 nippon


----------



## francisdemarte

I took a little hiatus from being a head-fi'er so it's been a while since I've checked in on this thread. I'm happy to see it's still going strong after all these years.
 Sometime this week I'll catch up on all the posts and update the links on the first post.


----------



## forumfan

Francisdemarte, nice to see you pay a visit.


----------



## liamstrain

Finally gathering the last pieces, and will start case building soon. 
  
 With a little luck, I'll get it wrapped up and running this week.


----------



## nippon

liamstrain said:


> Finally gathering the last pieces, and will start case building soon.
> 
> With a little luck, I'll get it wrapped up and running this week.


 
_4 weeks ago _
  
 Any updates?


----------



## liamstrain

Bah - life happened. It now looks unlikely until after the holidays.


----------



## theAmir

Hi,
 and thanks to the grate boys starting this thread. I bought a pcb and did a part list as here:
  

 part no.
 value
 X
 component
 1200808
 2.2UF, 400V, EPCOS - B32654
 2
 C6, C7
 1413949
 2.2NF, 1%, 250V, VISHAY KP1830
 2
 C6, C7
 1198551
 6800 uF 50v, PANASONIC TS-HA
 2
 C8, C9
 1166009
 0.15 uF 100v, MKT Vishay BC
 4
 C1, C2, C3, C4, C5
 1166009
 0.15 uF 100v, MKT Vishay BC
 4
 C10, C12, C13, C15
 1848452
 480 uF 35v, PANA FC, 10mm D
 6
 C16, C17, C18, C19, C20, C21
 9520660
 100 pF 1% 630V, Polystyrene
 2
 C24, C25
 9520430
 22NF, 63V, Polystyrene
 2
 C22, C23
  
  
  
  
 eBay
 10 uf 35v Tantalum
 2
 C11, C14
  
  
  
  
  
 VISHAY MBB02070 0.6 W ± 1 %
  
  
 60-591-57
 4.7 Ω
 4
 R1, R2, R3, R4
  
 7 Ω
 1
 R5
 60-591-98
 220 Ω
 2
 R6, R8
 18C6023
 BZX85-C13 13V, 1.3W, parallel x2
 4
 R7, R9
 60-591-81
 47 Ω
 8
 R10, R11, R12, R13, R14, R15, R16, R17
 60-592-19
 1.5 k
 4
 R18, R19, R20, R21
 60-592-23
 2.2 k
 3
 R22, R27, R34
 60-592-10
 680 Ω
 2
 R23, R26
 60-592-31
 4.7 k
 2
 R24, R25
 60-592-39
 10 k
 2
 R28, R29
 60-591-76
 30 Ω 0.6 W ± 1% (10 Ω 2W)
 12
 R30, R31, R32, R33
  
  
  
  
 70-096-07
 BYV27/200, Philips
 4
 D1, D2, D3, D4
 1084508
 BD139-16
 2
 Q5, Q7
 1084566
 BD140-16
 2
 Q6, Q8
 71-014-64
 BC550C
 2
 Q3, Q4
 71-014-66
 BC560C
 2
 Q1, Q2
 2102581
 LM317T, FAIRCHILD 1.2V to 37V
 1
 U1
 1013829
 LM337T, FAIRCHILD -1.2V to 37V
 1
 U2
  
 Your favorite OPAMP ex LME49720HA
 1
 U3
  
 Your favorite LED
 1
  
  
 Code switch
 2
 SW1, SW2
 eBay
 50 k DACT Type SMD Stepped Attenuator, my favorite!
 1
 VR1
 1611441
 HEATSINK, TO-220, 24.4C/W
 6
  
  
 3.5MM JACK, 3POLE
 1
  
 9531726
 MULTICOMP, 2 X 15V, 30VA
 1
  

  
 the parts are chosen from this thread as well. the part-numbers are from Farnell or Elfa in Europe. The component numbers are referd to this image from post #9468165
  
 Hope this can be useful to somebody.
  
 Bests/Amir


----------



## theAmir

could somebody check the diods direction in this image please? there are differences to the picture of original boards!
  
 why I get 6.6v from diodes?
  
 thanks


----------



## nippon

Hi  Amir,
  
 i have never seen this type of pcb by myself so you have to show me the otherside. Otherwise i could only guess whats wright or wrong.
 The partlist seems ok so far. I would suggest to match the resistors - so order a few more of each kind. You can never have enough resistors 
  
 kind regards,
 nippon


----------



## theAmir

thanks nippon, but I can not upload pix:
*Your account does not have the required permissions to access this page.*
  
Any way, I measured again there is 9.9v AC + 6.6v DC, thought something wrong with the BYV27/200's, after an R-core trafo or .... Changing them to 1N4007 still the same result!!! Getting mad. Any idea? Thanks.
  
 Regards


----------



## nippon

Hey Amir,
 you can take a picture and upload it to a free image hoster in the www. You get a link to the picture which you can post here.
  
 Without seeing your pcb i guess:
 1.The transformer is wired and/or not working correctly -> so take apart your build an check the transformer when it is connected to the energy socket. Compare your messurements with the data of the manufactur if possible. (Are you using an 2x +15V trafo? Than without connection there should be a reading of 2x +16-18V. Also double check your wiring and *take care of your own safety!!!*)
 2. Check your PCB and you solderconnections. Have you checked all diodes before installing them? Have you checked the capacitors in the power area?. And of course the pcb may have some issues 
  
 Bye the way -> it is normal that 18V AC are not equal to the DC output. The energy has to change their waves to become linear.
  
 So inform us what is going on with your Lovley Cube clone project! 
  
 Kind Regards,
 Nippon


----------



## theAmir

hi every one,
  
 got problem with! no sound! strange voltage as in the pix here
https://www.dropbox.com/s/1szufetorc9ma8b/theCube_Voltage01.jpg
 have R-Core transformer 2x15v.
  
 any help please? thanks!


----------



## theAmir

ohhhh it works. the main problem was the lousy output jack from Farnell "SCHURTER 3.5MM JACK, 3POLE". do not buy it. its beautiful and gold plated but big gap. I took it away from the part list.
  
 the cube sounds now. fine too.
  
 but  still a voltage difference. as the photo.


----------



## nippon

Personally, i think das PCB has a lousy layout. But it is small - advantage.
  
 The different voltage comes from the LM337/LM317. Read their datasheet and google how they work. Some people like me have used resistance trimmers to equal them ( http://szcanyi.en.alibaba.com/product/307861290-50332208/3296W_103_trimmer_resistor.html ).
  
 And where should i start... have you measured the DC-offset before connecting your headphones?


----------



## bbmiller

Quality kit

 hello
 I been reading this thread and think I am very interested in building one of these headphones amplifiers from a kit. But in one person's response to a question on this thread they said and I paraphrase, so you bought a kid on eBay that means you may not have gotten quality parts match components and things like that.

  So does anybody here have recommendations for a quality kit?

 Also is this thread one of a long line of clone threads? I am a newbie and will need PAC, headphone amp, and possibly when he a linear power supply if there is some way of getting one at less than audiophile prices. I mean repurposing one not intended for audiophile use or building a kit.

 Is there such a thing as a audiophile level of soldering? And if so is there any information on these forums or anywhere else on the web that somebody here may know about?


----------



## theAmir

hi, there is only junk kits like this one. or just search eBay for "lehmann kit". that's why I did a part list here; post #1089. the cmponent numbers are from the PCB.
  
 ask the seller for buying only the PCB only, or buy the kit and put the component package to the kids or recycling. and use the parts you want.
  
 good luck/Amir


----------



## bbmiller

So if I remember what you said you have to match the active components and make sure that matched. So is what you're saying that these kits aren't of a quality that you know the active components have been matched and you have to take it on luck and maybe by active components twice and some how  figure out if that matched?
  
 Well that leaves me thinking that maybe when these manufacturers charge you over $1000 to build one they are actually giving you something in the implementation that really must be worth something maybe not over $1000. But something.


----------



## nippon

Hi bbmiller!
  
 The kits on ebay are quite ok, but don't think you can build a high-end headphone amplifier for less than 25$ - also if you are not interested in DIY, buy a Matrix clone or a lovely cube.
 It can be really difficult to find a mistake in a circuit 
  
 Here is an example of a better pcb:
http://www.ebay.com/itm/High-end-stereo-Class-A-headphone-amplifier-PCB-1piece-/221131370084
  
 I would suggest you buy a full kit, so you get all necessary parts like headphone jacks, cooling parts, LEDs... etc.
 Afterwards you can start to evaluate what parts you would like to use. I recommend to swap all parts which are in the signal path.
 Especially BC550/560, BD139/140, opamp, all(!) capacitors
 Match the resistors, test the diodes and buy a high quality Alps porti...
  
 When you have made your list, you will know exactly what to buy additionally. The thread is full of suggestions.
 Be sure to check your PCB and your parts before soldering them. The pcb won't allow you to exchange parts too many times.
 I think you can realize an amp for about 80-130$ - depends on what you are planing to build.
  
  
 PS.: If you would like to make it perfect, then think about using resistor trimmers or a dedicated power supply like posted before: http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/1035#post_9505128
  
 PPS: Highend soldering technics? Make a fire by moonlight and sacrifice a lamb.... nah. There is only one important thing about soldering: Make solid and clean connections.


----------



## bbmiller

nippon said:


> Hi bbmiller!
> PS.: If you would like to make it perfect, then think about using resistor trimmers or a dedicated power supply like posted before: http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/1035#post_9505128


 

 Well - if a purchase I make from another member  goes through these further questions may be more for my own edification than anything else. But would it be very easy to repurpose a linear power supply not intended for audiophile use if it's the right voltage and save a lot of money that way. Is there something about building your own linear power supply which makes it superior to repurpose thing one not intended for audiophile use.
  
 resistor trimmers - do you mean resistors that are really potentiometers or have potentiometers in series with them? Could you link me to a picture or include one in your reply?


----------



## nippon

Some people think that the power supply of this circuit is one of his weakspots. When i use my clone, i can't here any hum or noise because my phones mostly got high impedance. For example when i once purchased a Audio-Technica ATH-M50, which has a very low impedance and high sensitivity, it was impossible to enjoy listening. Hum and noise everywhere...
 The other head-fi member and i talked a bit. After he got rid off the LM317/LM337 regulators, his clone went calm he says.
  
 There are some solutions which are quite nice and using these regulators, but this power supply is very primitive. For myself i'm sure the original has some better way to provide 2x +15V DC, but i have to find somebody who let me open his 1000$ amp 
 Just to name a better power supply: The objective O² is dead silent, even when a very cheap wallwart (which i can hear hum 
	

	
	
		
		

		
			





 ) provides the AC power .
  
 Kind regards,
 nippon


----------



## bbmiller

nippon said:


> I recommend to swap all parts which are in the signal path.


 
 Does slotting means docketing? If so whose or what sockets?


----------



## nippon

bbmiller said:


> Does slotting means docketing? If so whose or what sockets?


 
 ?
  
 There is only one socket: The DIP-8 OPA (operation amplifier)... slotting...docketing 
	

	
	
		
		

		
		
	


	



 From which country are you?


----------



## bbmiller

USA
 Perhaps I should explain. I do all my posting through speech dictation I have a spelling disability. And if I am anxious or want to make a post quickly I sometimes don't proof it properly. I do not think that was a US expression it was just my poor lack of proofing because I was doing a quick post that I was doing being hungry at the time.


----------



## nippon

Okay, I understand. I just thought there is a little chance that you are from Germany and i could explain some things very easy to you in german 
 If you need some advice in picking parts or choosing a kit on Ebay - just send me a private message. Definitely I am not a expert, but when I build my clone, I did so many mistakes from which i learned a lot about this circuit.
  
 Kind regards,
 nippon


----------



## bbmiller

nippon said:


> I would suggest you buy a full kit, so you get all necessary parts like headphone jacks, cooling parts, LEDs... etc.
> Afterwards you can start to evaluate what parts you would like to use. I recommend to swap all parts which are in the signal path.
> Especially BC550/560, BD139/140, opamp, all(!) capacitors
> Match the resistors, test the diodes and buy a high quality Alps porti...


 
 now that I established I may need a little understanding sometimes with my spelling not immediately being understandable let me venture in trying to spell things right and ask to other questions.

 So what I think you are saying is not to use any parts in the single path even though they come with the kit? From the above would you all so only use 1% resistors if you want to do things right and all your projects? And if you changed out all the parts in the single path are there rules of thumb (general guidelines) as to what parts in the single path would be better than the parts they give you?

 Also as a general project guideline for all your projects would you say pinouts on op amps are generally the same? Can you read about the latest and greatest op amps and think most of them will be compatible as better ones for your projects and even to swap out in your own equipment? Are there things about op amps other than equivalent pinouts which will make them not compatible in equipment?


----------



## nippon

When you order one of the cheap kits, you will maybe get a good one. But there is a risk of getting not the best parts for the circuit.
 Just one example: When I get my kit, I didn't get the BC550/BC560 transistors. They sent the nearly equal BC546/BC556. But there is one major difference - only the BC550/BC560 are made for low noise operating
 If you buy a cheap kit - you get cheap parts - so you will get cheap sound!
  
 And for the OPA Question:
 You have to read the datasheets for every single one. Some are nearly the same as OPA2132 or OPA2134 are (which are quite good for these headphone amplifier).
 But there are also other pin models. These are OPAs made for audio amplifying, but they are only a small part in the family of operation amplifiers, which are used for nearly any circuit you can imagine.
  
 I recommend you to start with a smaller project like the Cmoy or the Objective O². If you really want to build this type of amplifier, please read the thread.
  
 Kind regards,
 nippon


----------



## PTom

Is the performance of this identical to the black cube linear?


----------



## nippon

Yes and no 
 Read that thread from post #8 to #15
 http://www.head-fi.org/t/545225/lehmann-audio-black-cube-linear-headphones-amp-pictures#post_7364890
  
 It's a copy and if you are going to build it yourself, you can influence how good the result is.
 Maybe it is better to compare it with other DIY amps. My DIY LC clone sounds way better than my Objective², which has clearly more power than my Cmoy.
 I'm allready planing to build another clone with a better power supply and higher quality parts.
  
 In my opinion the circuit is nothing special. If your intention was to ask if you can buy the same "high-end" product for less money, then the answer is no.
 You have to pay more money or invest some of your spare time in that amp (remember: time is money).
  
  
 (BTW: The Matrix M-Stage websites says that their amp is nearly identical to the Black Cube Linear regarding to the technical information)


----------



## PTom

Hi nippon, thanks for the information! Very helpful. I'm planning on buying the pre-assembled lovely cube. I think you are right my "intention is to ask if I can buy the same "high-end" product for less money". The preassembled LC is $250 which is much cheaper than the BCL and if their performance is similar I'd rather  buy the LC.
  
 I am also looking at the matrix m stage since I heard this is very similar to the BCL too. Any thoughts?


----------



## PTom

Also I was just wondering why there isn't a product page for the LC?


----------



## nippon

The prices of the Premium Lovely Cube and the Matrix M-Stage are nearly equal. A pre-assembled Kit + case + transformer looks like a good deal. But i would ask the seller if the parts are chosen ones and where is the advantage between that deal and the Premium version. It's pretty difficult to say which offer is better


----------



## mikaelmark

Yes, there are a homepage for the LC, just google at: alicemagicbox
  
 Stephen, alias lasercollection at ebay, having this page. You can see every component and photos of the PCB.
  
 I´m a bit worried my BYV27-200 Ultrafast 25 ns will generate noise, and has been recommended to solder a film capacitor at 100 nfn in parallel for each diods. I´ve read that i may be a good idea to also have a resistor in parallel.
  
 Is there someone who has tried this, or have some thoughts?
  
 Found this page: http://www.hagtech.com/pdf/snubber.pdf
  
  
 Best regards: Mikael Markstrom


----------



## mikaelmark

mikaelmark said:


> Yes, there are a homepage for the LC, just google at: alicemagicbox
> 
> Stephen, alias lasercollection at ebay, having this page. You can see every component and photos of the PCB.
> 
> ...


----------



## cls

I started looking into a "serious" headphone amp for my desktop and not mobile use
  
 After reading various post I went and just bought this
 http://www.ebay.com/itm/121151033353
 124€ ~171 USD
  incl. Shipping
  
 I HAVE to try that.
  
 I currently only own
 PA2V2 from canada www.electric-avenues.com
 Cmoy Amp by Zigis Audio Lab with both *OPA2134 or LM4562 to switch (but I only use the OPA2134)*


----------



## nippon

Hi
 I bought my clone kit also from "along". I'm very interested how his amp sounds. The build quality looks good and the price is competitive.
 Would be very nice if you post your feedback here.
  
 kind regards
 nippon


----------



## Amictus

I own a Lovely Cube (pre-assembled) and am finding it very good, for the price, with my HD800s. It puts some muscle (and ambient hall sound) into the mix in a way that none of my tube-rolling with my Schiit Lyr has quite equalled. In some ways, of course, (smoothness, control, clarity), the Schiit is way ahead. This has caused me to wonder if anyone has compared it to the Lehmann Black Cube directly? Forgive me for not having gone through the 75 pages of this thread before asking the question... I really like the sound of the Lovely Cube. It is a tremendous bargain.


----------



## Amictus

amictus said:


> I own a Lovely Cube (pre-assembled) and am finding it very good, for the price, with my HD800s. It puts some muscle (and ambient hall sound) into the mix in a way that none of my tube-rolling with my Schiit Lyr has quite equalled. In some ways, of course, (smoothness, control, clarity), the Schiit is way ahead. This has caused me to wonder if anyone has compared it to the Lehmann Black Cube directly? Forgive me for not having gone through the 75 pages of this thread before asking the question... I really like the sound of the Lovely Cube. It is a tremendous bargain.


 

 Alas, no comments on the direct comparison between the Lovely Cube and its German godfather, the Lehmann Black Cube Linear (not to mention the Linear SE)... Sad face. PMs welcome on the subject.
  
 I have to say that I seriously misjudged the Lovely Cube. I saw it as something temporary until I could afford something better. Well, I have discovered that it has been liberated by the acquisition of the Schiit Gungnir DAC and it's amazing synergy with the Sennheiser HD800s. I am now upgrading the power cables and the interconnect and the Lovely Cube just steps up at every improvement. It may come at a modest price, but it has enormous upgrade potential in terms of the equipment that it is paired with. Remarkable.
  
 I'm still curious about the Lehmann products, though. Anyone?


----------



## nippon

I have read a nice quote in a magazine:
 "Enjoy spending less money for a clone - get annoyed for a long time.
 Get shortly frustrated while spending a pretty penny for an original - become satisfied for a lifetime"
  
 The realitiy is somewhere inbetween


----------



## mikaelmark

I´m building my own clone to Lovely Cube with PRP9372 resistors, Audyn Plus or True Copper as coupling caps, Dale ladder volume switch, 4 pcs Nichicon KZ Muse 1000 uF and 2 pcs Elna Silmic II 470 uF, ST/ Fairchild LM317/ LM337, Russian FT-1 teflon as bypass/ voltage to ground, BYV27-200 with 0,1uF caps, THS4032/ OPA627 in Class A and 2 pcs MLytic AG 10000uF. Also, I want to use CDIL BD139/140-25 as they have higher hfe - but they´re so hard to get.
  
 Do someone think it will be fine using 2 pcs 22000uF with only 25 Volt (they get 20 Volt from they circuit)? And is 22000uF way to high? Howeverhey, they will fit on the PCB. Or maybe it´s best to go ahead with 10000uF 40 Volt?
  
 PS: I want to acquire this post in memory of my cat Tussan I´m using in my avatar, that died yesterday - should have been 20 years in a couple of weeks. R.I.P.
  
  
 Best regards: Mikael Markstrom


----------



## mikaelmark

mikaelmark said:


> I´m building my own clone to Lovely Cube with PRP9372 resistors, Audyn Plus or True Copper as coupling caps, Dale ladder volume switch, 4 pcs Nichicon KZ Muse 1000 uF and 2 pcs Elna Silmic II 470 uF, ST/ Fairchild LM317/ LM337, Russian FT-1 teflon as bypass/ voltage to ground, 100pF Styroflex polystyrene, BYV27-200 with 0,1uF caps, THS4032/ OPA627 in Class A and 2 pcs MLytic AG 10000uF. Also, I want to use CDIL BD139/140-25 as they have higher hfe - but they´re so hard to get.
> 
> Do someone think it will be fine using 2 pcs 22000uF with only 25 Volt (they get 20 Volt from they circuit)? And is 22000uF way to high? Howeverhey, they will fit on the PCB. Or maybe it´s best to go ahead with 10000uF 40 Volt?
> 
> ...


----------



## cls

I got my Lehman BLC Clone from eBay Seller along1986090
 Shipped by DHL Express it arrived within 6 Days (!!!)
 I paid 124€ for this unitl
  
 I took some pictures to show the actuall inside parts.
  

It has the Opamp OPA2134
Lots of WIMA brand capacitors
NOVER LA Audio Grade Power Capacitor 10000µF 35Volt
Siemens capacitor for Coupling
and a Black Epoxy / Steel shielded transformator
  
 I was curious since the whole thing is NOT grounded, the ground Wire on the 220V intake is not connected to the PSU the Cable is left blank?
 But there is a GND wire on the PSU outlet connected to the PCB.
 I did bridge the 230V directly with the PCB with a small cord show in the pictures.
  
 I kind a have a "ground" noise, teseted with my Samsung Galaxy S4 > USB OTG  > UD110 MK. II DAC > Beyerdynamik DT990 
  
 I want to make sure to get as close as possible to the "original" thing by Modding and upgrading.
  
 Do you have anysuggestions?


----------



## francisdemarte

Unplug all  your sources. Do you still have ground noise with just the power and headphones plugged in? Try another electrical socket also.


----------



## Danielsc

mikaelmark said:


> I´m building my own clone to Lovely Cube with PRP9372 resistors, Audyn Plus or True Copper as coupling caps, Dale ladder volume switch, 4 pcs Nichicon KZ Muse 1000 uF and 2 pcs Elna Silmic II 470 uF, ST/ Fairchild LM317/ LM337, Russian FT-1 teflon as bypass/ voltage to ground, BYV27-200 with 0,1uF caps, THS4032/ OPA627 in Class A and 2 pcs MLytic AG 10000uF. Also, I want to use CDIL BD139/140-25 as they have higher hfe - but they´re so hard to get.
> 
> Do someone think it will be fine using 2 pcs 22000uF with only 25 Volt (they get 20 Volt from they circuit)? And is 22000uF way to high? Howeverhey, they will fit on the PCB. Or maybe it´s best to go ahead with 10000uF 40 Volt?
> 
> ...


 

 Hello Mikael,
  
 I'm impressed with the choice of components you made. They are at 85% the same I selected.. I selected them after a lot (really a lot) of tests, between several components.
 For my part, If we do not talk about the identity of the Opamp, the biggest upgrade seemed to me, to have choosen the PRP résistors..
 But, I wanted to know if you did test components, to select the one you write, or did you get advice from somebody?
 I also did make the step to mount an external power supply, (see post 1042 on page 70). It helps a lot and gave very good dynamics..
  
 And, very impressive too, is the fact you chose nearly the same DAC to mount, than I did.
  
 After some months I did not change anything, I'm now ready to build a.. Balanced project, with twoo PCB's, with all the selected components, with separate PSU..
  
 Unfortunately, I can not help you about the Big 10000 caps.. My choice, when I needed them, was to use Mlytic AG 4700µf 40 volts.. And they never went warm.
 I use them on the separate PCU pcb, now.
  
 And, sincerly, I'm really sorry about your cat.. Nearly 20 years is very high..
  
 Regards.
  
 Daniel


----------



## nippon

I never found a reference for that 10.000uF 35V capacitors at the manufacturer. Maybe they are only for OEM or they are fakes. But sincerly, i've takin apart some larger amplifiers for speakers and the largest capacity i found, was 8200uF. Also keep in mind that the elko capacity can rise when you use them below their volt-level after some time.
  
 Is the Alps poti well grounded? Can you hear it with your headphones, if you touch the volume knob?
 And sorry to ask for it again, but did you measure the dc-offset?


----------



## mikaelmark

Thank´s for you reply, Daniel!
  
 My choices were made after reading a lot of tips at forums, like this. And, after my first Lovely Cube clone, that some humming sound in the background and with moderate sound quality (even my modded Project Headbox II at under $200 had a better sound).
 So now I decided to build two more of them and go all the way using "the best" components. (I know, there are always something better and sometimes there are preferrables choices).
 I´m posting a picture of my first amp.
  
 I´m now also thinking of solder the components for the power supply section at the downside at the board, due to the large components (Nichocon KZ Muse 1000uF 50V is really large with an diameter of 18mm!!), and also I think there will be some shielding protection to having the the signal path at the other side of the PCB. I know it sound weird, but this will include having the 10000uF MLytic filtering caps soldered under the PCB.  After everything is soldered and I see the measurements, I will make an aluminium enclosure for it.
  
 As for the two10000uF MLytic (replacing the standard 4700uF 35V), I´m not shure if it will be enough if they´re rated at 25V, or if they should be spec´d at 40V? Have measured the voltage for them, and the power supply circuit will give 20V for them. So 25V will be enough at the paper, but I don´t now in the real life if there if some downside, for example bad transients or shorter life span?
  
 Also, I´ve seen the BHC ALC10S1080DF from UK, using Slit Foil, will better than Mundorf MLytic? The price is approximately the same. I´ve seen one person claim the 10000 MLytic for his amp sounded slow, but many others say it´s better then Vishay BC, Panasonic TS-HA, Elna LAO and Nichicon KG. Don´t know so much about the BHC. 
  
 Daniel; what OpAmp did you use? Did you use Class A for it? I think I´m gonna choose two 3,9kOhm resistors for mine. And did you found any differents in sound swapping OpAmps or resistors for it?
  
  
 Best regards: Mikael Markstrom


----------



## Danielsc

Hello Mikael..
  
 I think you went the same way I did..
 I'm now improving my version 3, made with the components we both choosed.
 I'm now working on the PSU.. I already use one type, just like the one on the link in my previous post.. I'm looking for some other, with better diodes..
  
 And, afterwoods, I'll try the balanced way.. I already buyed every component (also the same).. I only still have to order two Talema transformers..
 After that, I'll concentrate on the DAC.. Maybe a ES9018 one..
  
 About opamp, my choice is based on the OPA2111AM.. It is my favorite..
 But I like the LM49720HA too, wich is very close in quality.. Its a mather of taste..
  
 Best Regards
  
 Daniel


----------



## cls

mikaelmark said:


> Thank´s for you reply, Daniel!
> 
> My choices were made after reading a lot of tips at forums, like this. And, after my first Lovely Cube clone, that some humming sound in the background and with moderate sound quality (even my modded Project Headbox II at under $200 had a better sound).
> So now I decided to build two more of them and go all the way using "the best" components. (I know, there are always something better and sometimes there are preferrables choices).
> ...



Dude awesome would you mod my Lehmann Clone for money too?


----------



## mikaelmark

Off course, I can! The problem is that I live in Sweden, and I think the shipment cost will be quite high.
  
 However, I´ve bought more components then I need, so I have some extra.
  
 Where do you live? I must say if it´s you at the picture, I think you like a famous stand up comedian here in Sweden, called Özz Nujen 
  
 http://www.lifeline.se/wp-content/uploads/2012/02/%C3%96zzN%C3%BBjen3_FotoSannaDahl%C3%A9n_highres.jpg


----------



## cls

mikaelmark said:


> Off course, I can! The problem is that I live in Sweden, and I think the shipment cost will be quite high.
> 
> However, I´ve bought more components then I need, so I have some extra.
> 
> ...


 

 lol.. looks like my uncle... haha
 send you a pm thx


----------



## mikaelmark

Whoaa, now I´ve found something very interesting!!
	

	
	
		
		

		
			




  
 DT9205A is an multimeter that can also measure capacitors by capacitance (2nf - 200uF/ not sure about up to 2000uF) and measure transistors by hFE.
  
 So this little marvelous thing can be just fine for matching those BD139, BD140 and BC550C, BC560C. And the price will only be about $10. You have to pay a LOT more, about $400 for a Fluke, but even soit can not measure hFE!
  
 People selling those transistors matched at ebay, will have a lot more payed for them then unmatched.
  
 http://www.head-fi.org/t/249447/what-dmm-you-use-to-match-transistors-hfe
  
  
 Mikael Markstrom


----------



## nippon

mikaelmark said:


> Whoaa, now I´ve found something very interesting!!
> 
> 
> 
> ...


 
   
Thank you, i ordered one 2min ago. I own a pretty nice multimeter for capacitors cap., but i was missing the hFE meassure method.

 The next clone will be way better, than my first. Maybe the DMM is worth the money, even if it is not super precisely like my 100$ UNI-T device.
  
 I think that matched transistors, ressistors and capacitors will deliver more value than "high-end" components. There were some people talking in this thread about the input capacitors and if they are really nessasary because they will allways influence the audio signal. Maybe they are expendable, when there is a optimized circuit. I'm just daydreaming, but the next step would be swapping the nasty OPA for a discrete amp circuit.
  
 kind regards


----------



## cls

@mikaelmark
 Is your offer still valid, you havent replied to my PM yet.. you can conact me via facebook/skype whatever you like
 kind regards


----------



## mikaelmark

Now I´ve contacted the manufacturer CDIL in India, and they can sell 200 pcs BD139-25 and 200 pcs BD140-25. But the shipping cost and bank transfer cost will be quite high. I think those will even be better (higher hFE) than the old Philips/ NXP!
  
 I also gonna buy 50 pcs BC550C and 50 pcs BC560C. And I´ve also bought 8 pcs of Intertechnic Audyn True Copper 1,5uF (at least as good as Clarity Cap MR and almost up to Duelund and V-Cap TFTF/ CuTF)
  
 As I just also bought hFE -meter, I´m gonna be able to match all of the above 
	

	
	
		
		

		
		
	


	



  
 So; do someone want any of the above from me? For Lovely Cube, it will use 2 pcs of each.
  
 The Audyn True Copper costs about USD 120/ pair.
  
  
 Best regards: Mikael Markstrom


----------



## Amictus

You guys with soldering irons make me envious. My standard Lovely Cube, as built by Stephen and Co., is pretty marvelous. I prefer it to my Schiit Lyr with my HD800s. I am arranging to audition the Lehmann Linear and Linear SE, in case anyone is interested in the results... If the clone is this amazing, how will the original sound?
  
 Update, FWIW - I heard the Linear and Linear SE, both not much burned-in, up against my Lovely Cube (burned-in). The Linear sounded a bit contained, but pleasant. I preferred the sound of the Lovely Cube with the HD800. The Linear SE sounded nearer to the sound of LC, but took things to another level. I bought it. The sound is superb.


----------



## mikaelmark

I hav´nt heard the original Lehamann BCL, but the stuff coming with the ebay-clones is not that terrific. But upgrading it is not so difficult and must not be so expensive. For me, I think it will cost about $300-400/ clone - and I´m doing two of them.
  
 Stuff I´m using: Audyn True Copper 1,5uF, Mundorf EVO aluminium 2,2uF, FT-1 0,022uF, Styroflex polystyrenes 100pF/ 0,022uF, ST/ CDIL BD139/140-16/25, BC550/560C, , Nover Audio Grade/ Mundorf MLytic 10000uF 35/40V,  Alps RK27 "Blue Velvet", 24 step ladder volume pots, Vishay/ Philips BYV27 rectifier diods, LM317, Fairchild LM337, Wima MKP4 0,15uF, Wima MKP10 0,022uF, PTC, OFC-wires, RCA/ Phono jacks/ plugs, R-Core and other transformer, NE5532 and THS4031/4032 on Brown Dog adapter (should even be better then OPA627).
  
 So, as I told in the earlier post; If someone want any of those stuff I´m using, please PM me, as I´ve bought more than I need. 
	

	
	
		
		

		
		
	


	



  
 The Lehmann Linear SE, with Mundorf caps (M Cap as decoupling caps, it´s jus so so - about the same grade as Wima MKP10 for <$10), better internal wiring cables for the signal etc is a tad better then the standard BCL. Also, the price is about the same as the standard BCL.
  
 https://www.lehmannaudio.com/assets/site/home_audio/pre_amps/linear_se/pdf/Lehmann-STEREO-02-2012-ENG.pdf
  
 But yes, It should be very interesting to read your experience for the Linear SE to BCL!
  
 For myself, I´m using Sennheiser HD600/650/800, Ultimate Ear Triplefi 10 and modded AKGK702. Other amp´s I have is: modded ProJect Headbox II, modded Meier  Corda Swing and Harmony Design Ear 9. Other thing´s I´ve modded is my Arcam CD192 CD-player, Squeezebox 2, Creative X-Fi Elite Pro soundcard, speakers and some DAC´s I´ve built/ modded. (I can sell some of the above, if someone is interested - please PM me!)
  
  
 Best regards: Mikael Markstrom


----------



## mikaelmark

mikaelmark said:


> I hav´nt heard the original Lehamann BCL, but the stuff coming with the ebay-clones is not that terrific. But upgrading it is not so difficult and must not be so expensive. For me, I think it will cost about $300-400/ clone - and I´m doing two of them.
> 
> Stuff I´m using: Audyn True Copper 1,5uF, Mundorf EVO aluminium 2,2uF, FT-1 0,022uF, Styroflex polystyrenes 100pF/ 0,022uF, ST/ CDIL BD139/140-16/25, BC550/560C, , Nover Audio Grade/ Mundorf MLytic 10000uF 35/40V,  Alps RK27 "Blue Velvet", 24 step ladder volume pots, Vishay/ Philips BYV27 rectifier diods, LM317, Fairchild LM337, Wima MKP4 0,15uF, Wima MKP10 0,022uF, PTC, OFC-wires, RCA/ Phono jacks/ plugs, R-Core and other transformer, NE5532, LM4562 and THS4031/4032 on Brown Dog adapter (should even be better then OPA627).
> 
> ...


----------



## nippon

mikaelmark said:


> And I´ve also bought 8 pcs of Intertechnic Audyn True Copper 1,5uF....
> 
> The Audyn True Copper costs about USD 120/ pair.


 
 I've paid about 20$ for my Mundorf input capacitors (2,2uf)... but that is insane 
	

	
	
		
		

		
		
	


	



 Looking forward to hear from your results.
  
 By the way, i would like to buy a bigger amount of BD140/BD139 transistors from *ST MICROELECTRONICS*, so are the CDIL / Philips ones so much better?
  
 Kind regards
 nippon


----------



## nanchangbob

nippon said:


> I've paid about 20$ for my Mundorf input capacitors (2,2uf)... but that is insane
> 
> 
> 
> ...


 

 I think you will have difficulties finding genuine Philips transistors.  Most of the one you see on Ebay are fakes from China.  I know first had because I'm living here and see them all the time.
  
 I changed capacitors from Wima Mkp 10 to Mundorf ZN capacitors I got on a bargain basement sale.  There was an improvement but I think the power supply is it's weaker point.  The LM317 and LM337 are not the best or quietest regulators available. "They are easy and cheap"  I have a couple of PCB designed by Salas on the diyaudio forumn which are shunt regulators that measure extremely low noise.  I almost have all the parts now.  This will be a lot of work but I think it will make a bigger difference. IMHO!


----------



## mikaelmark

The CDIL BD139-25 and BD140-25 will have about 60% higher hFE than the -16 (original standard), and they are about 60% better then -10 (cheap ebay clones). And I think hFE will be important when used in audio.
  
 I know there are some expensier voltage regulators for about $100, but the LM317 (negative) and LM317 (positive) are popular and used in many cirsuits - but be shure they are from known manufacturers, like Fairchild, ST Microelectronics etc, and not cheap china-clones.
  
 For myself, I´m gonna use thermal compound for regulators and transistors heatsinks.
  
  
 Best regards: Mikael Markstrom


----------



## mikaelmark

mikaelmark said:


> The CDIL BD139-25 and BD140-25 will have about 60% higher hFE than the -16 (original standard), and they are about 60% better then -10 (cheap ebay clones). And I think hFE will be important when used in audio.
> 
> I know there are some expensier voltage regulators for about $100 I think discussed earlier in this post, but the LM317 (negative) and LM317 (positive) are popular and used in many cirsuits - but be shure they are from known manufacturers, like Fairchild, ST Microelectronics etc, and not cheap china-clones.
> 
> ...


----------



## nanchangbob

Actually mine sounds very good right now and I listen to it more than my other amps.  I've just built some amps and preamp's and found the more I lowered the noise floor the more information came through and
 I wanted to push this one farther and see what it does.
  
 The 317 and 337 are not bad and can be made even better with some circuit tweaks.  I'm not about to cut-up  this board to try adding them.  It will be easier for me just to build the low noise shunt regulators.  Here is an article on regulators and noise if your interested.  http://www.tnt-audio.com/clinica/regulators_noise2_e.html
  
 There are some more articles in the EE magazine but most of that goes over my head.


----------



## DeGato

mikaelmark said:


> Now I´ve contacted the manufacturer CDIL in India, and they can sell 200 pcs BD139-25 and 200 pcs BD140-25. But the shipping cost and bank transfer cost will be quite high. I think those will even be better (higher hFE) than the old Philips/ NXP!
> 
> I also gonna buy 50 pcs BC550C and 50 pcs BC560C. And I´ve also bought 8 pcs of Intertechnic Audyn True Copper 1,5uF (at least as good as Clarity Cap MR and almost up to Duelund and V-Cap TFTF/ CuTF)
> 
> ...


 

 Hi Mikael,
 The advantage of Philips BD's is not in their hFE. The hFE of BD's in the LC is not important because they are in a buffer circuit.
  
 For those of you guys who has a little humm from the amplifier, consider the nippon's suggestion: http://www.ebay.com/itm/High-end-stereo-Class-A-headphone-amplifier-PCB-1piece-/221131370084
 I've built several LC clones and I have good reports from the owners who have their amps based on a newer revision of the PCB.


----------



## mikaelmark

But why does many people says the BD-1xx-16 and BC5x0C is better than BC-1xx-10 and BC5x0B. And that the -16 is the HiFi section?
  
 The only thing I can see differ is the hFE.
  
 Do you also think the hFE is not important for the BC5x0?
  
 Also, What is the advantage for tis PCB? Is it a newer revision or thincker copper connections? And will it have any difference in connections/ printing diagram? (I have the standard blue China PCB, YS-AUDIO)
  
  
 Best regards: Mikael Markstrom


----------



## DeGato

mikaelmark said:


> But why does many people says the BD-1xx-16 and BC5x0C is better than BC-1xx-10 and BC5x0B. And that the -16 is the HiFi section?
> 
> The only thing I can see differ is the hFE.
> 
> ...


 

 There is no the best or the worst. Every selection grade has its purpose. Generally -10 -16 or B, C selection has nothing in common with audio. It comes from the manufacturers and describes just limits within which one particular transistor from the whole bulk will have its hfe.
  
 When it comes to BC5** in the buffer their hfe affect the input impedance of the buffer. It is important if you use OPA which can't handle heavy load with a relatively small impedance. In this case hfe of the BC5** should be quite high. In the other hand, too high hfe has its drawbacks. Another important thing is hfe/current diagram. Depending on how much current flows through a transistor or its temperature the hfe will vary. In the best case the drift of hfe should be as less as possible in a given interval.
 It is also worth to consider the thermal drift and the internal capacitance of a bipolar between its pins if you want to achieve a stable and predictable result.
  
 The green PCB has slightly different layout in the flip side. But it is still not the best. I am working on my own revision of a PCB with completely separated channels with headphone protection and separate filters, voltage regulators, and rectifiers for each channel optimized for audio components.
 http://www.mightything.com/lc/images/BCLv2_alpha.jpg
  
 Cheers.


----------



## mikaelmark

So; What is the difference between the old Philips/ NXP BD1xx? Why are they better the newer Fairchild, ST Microelectronics, On Semi, CDIL etc?

/ Mikael Markstrom


----------



## DeGato

mikaelmark said:


> So; What is the difference between the old Philips/ NXP BD1xx? Why are they better the newer Fairchild, ST Microelectronics, On Semi, CDIL etc?
> 
> / Mikael Markstrom


 
 Some explanation is here: http://www.diyaudio.com/forums/parts/97030-bd139-16-bd140-16-anyone-use-these-transistors.html


----------



## mikaelmark

Thank´s DeGato!
  
 I see this green ebay PCB will have thicker copper inside, 4 times normally, they said. Maybe that´s a big advantage also.
  
 What do you mean with "flip side" of the PCB? If it has a different layout, will it require different components or values than the standard BCL/ Lovely Cube?
  
 For the BD140, I have some old genuine Philips  - but they are just BD140-10. Do you think those will do better in this circuit then new versions of BD140-16, like ST, On Semi etc?
  
 And is there any of the new BD1xx-16 to prefer/ will any of the following be better than the other: ST Microelectronic, Fairchild, On Semi, CDIL, Taiwan...?
  
 Also, if the hFE for those will not be important in this circiut, still I guess it will be important to match them, by use all 4 ones with similar hFE and mabye also measure them by capacitance and resistance?
  
 http://www.wikihow.com/Test-a-Transistor
  
  
 Thank´s in advance: Mikael Markstrom


----------



## DeGato

mikaelmark said:


> Thank´s DeGato!
> 
> I see this green ebay PCB will have thicker copper inside, 4 times normally, they said. Maybe that´s a big advantage also.
> 
> ...


 
 The green PCB require the same components as the blue one. In the original design of the BCL there are just minor changes in capacitors. "Flip side" - the bottom side.
 As for the "modern" BD's, I would choose between ST Microelectronic, Fairchild or On Semi (try some of them, measure and listen).  The matching process for small power transistors described here: http://www.diamondstar.de/transistor_matching_bjt.html For medium power transistors you should increase IC (collector current) during the matching process for proper results (consider the same as in the amplifier). Matching capacitance is not important, just keep it as low as possible.
  
 Cheers.


----------



## mikaelmark

How about these: http://www.ebay.com/itm/50PCS-BD139-TRANSISTOR-NPN-1-5A-80V-TO126-NEW-GOOD-QUALITY-TO2-/121119586369?pt=LH_DefaultDomain_0&hash=item1c334a3841
  
Looks like those comes in the ebay-kits, and are maybe not original NXP. But it would be nice to have so many when matching.
  
  
/ Mikael Markstrom


----------



## DeGato

These are fakes. I've bought the similar transistors which now I have no idea where to use. Better use Farnell, DigiKey, Mouser for component purchase.


----------



## mikaelmark

May the korean KEC be any good?
  
 http://www.ebay.com/itm/50pcs-New-GENUINE-KEC-BC550C-NPN-LOW-NOISE-BJT-AUDIO-TRANSISTORS-/171187163093?pt=Vintage_Electronics_R2&hash=item27db8ccfd5
  
 http://www.keccorp.com/


----------



## DeGato

http://de.mouser.com/Search/Refine.aspx?Keyword=bc550
 Why don't you use official reliable suppliers?


----------



## mikaelmark

Now I´ve received all the capacitors, and measured all of them. The Mundof MLytic 10.000uF are +- 20%, and they measured between 9.33x to 10.18x, and that is within 10%. But when I matched them, all was paired within 3,5%. And thre pairs measured exactly the same with two decimals like 9,69. Quite impressive!
  
 Also, the Silmic II 470uF 50V and Muse KZ 1.000uF 50V measured well, paired 2pcs and 4pcs.
  
 I also bought 2pcs of the Nippon´s recommended PCB´s from Jim´s Audio. Now I´m just waiting for the Audyn True Copper 1,5uF, that I´ve bought from europe-audio.com 6 weeks ago, they´re still backorder.
  
 So as I told befor, if someone want to buy anything of my stuff, please tell me. I have a lot more than I need 
	

	
	
		
		

		
		
	


	



  
 It´s also possible to buy a complete kit, unsoldered or soldered with your choosed compontents - I will give a nice deal, course I´m not doing this to earn money. Just because it´s fun and that I have bought too much to get better prices! I will use unleaded RoHS -solder and have good soldering skills. I have just sold one complete soldered kit with OPA627 in Class A.
  
  
 Best regards: Mikael Markstrom


----------



## mikaelmark

Now I found a store autemashop.com here in Sweden selling BD139/140-16 (ST) and BC550/560C (ON Semi) at ebay:
  
 http://www.ebay.com/itm/111310652096?_trksid=p2055120.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
  
 The prices are really affordable and they will ship to Europe and US.
  
 I just bought 40 pcs BD1xx-16 and 100 pcs BC5x0C.
  
 And I also have to say, when I upgraded my first Lovely Cube with RK27 volume pot, some polystyrenes and "snubbers" (0,1uF caps) to bypass the rectifier diods BYV27, the sound was getting much quiter.
  
 So now I´m just waiting to start building my two new amp´s, just a few things left to get.


----------



## mikaelmark

I have just received the transistors, BC550C and BC560C is On Semi and BD139-16 and BD140-16 is Fairchild (not ST Microelectronics).
  
 But the BD´s do not have any metal survace at the back of them, please see pictures below. Do the Fairchild not have metal surface on their transistors? Will the heat dissipation for the heatsink be equally good?
  

  

  
 / Mikael Markstrom


----------



## mikaelmark

I see that Fairchild warn for counterfeits: http://www.fairchildsemi.com/includes/sharedText/counterfeitPartsPolicyStatement.html
  
 Here are also a picture of some LM337 that I have. May all those be genuine Fairchild, or are any of them maybe counterfeits?
  
 / Mikael Markström


----------



## aneker

Citação: 





> Postado Originalmente por *DeGato* /img/forum/go_quote.gif
> 
> Não existe o melhor ou o pior. Cada grau de seleção tem a sua finalidade. Geralmente -10 -16 ou B, a seleção C não tem nada em comum com o áudio. Ele vem das fabricantes e descreve apenas limites dentro dos quais um transistor especial de toda a massa terá sua hfe.
> 
> ...


 
 Olá 
 Esta versão parece interessante,  
 já tentei essa versão da dupla mono?  
 joga bem, melhor do que Lehmann?


----------



## DeGato

aneker said:


> Olá
> Esta versão parece interessante,
> já tentei essa versão da dupla mono?
> joga bem, melhor do que Lehmann?


 
 It measures a bit better. More space and the overall performance is better. Personally, I prefer it over the original one. It also has important protection circuit for headphones. It's important in case if you have expensive or rare headphones


----------



## DeGato

Plastic body is ok in some cases. I've seen genuine parts made like that.
 In case if you are not sure about the origin it's better to send an e-mail with some photos to the company which produce those chips.
 The same for Fairchild.


mikaelmark said:


> I have just received the transistors, BC550C and BC560C is On Semi and BD139-16 and BD140-16 is Fairchild (not ST Microelectronics).
> 
> But the BD´s do not have any metal survace at the back of them, please see pictures below. Do the Fairchild not have metal surface on their transistors? Will the heat dissipation for the heatsink be equally good?
> 
> ...


----------



## FOXY

What the OPAMP originally found in the Lehmann Black Cube Linear?


----------



## DeGato

opa2134


----------



## aneker

degato said:


> It measures a bit better. More space and the overall performance is better. Personally, I prefer it over the original one. It also has important protection circuit for headphones. It's important in case if you have expensive or rare headphones


 
  
 Could put some pictures so we can enjoy?
  
 At the moment I am also building a version identical to the original with PRP resistors. I do not know what this is going but I've read somewhere that these resistors have a cooler and shrill sound!


----------



## FOXY

I purchased the amp today, works well with the DT880. 
  
 Which OPAMP recommended with this amp?


----------



## mikaelmark

The lower economy class: NJM2068 NE5532, OPA2134, OPA2604
  
  
 Middle class: AD8620, OPA1612, LM741 (never used)
  
  
 Top class: OPA627, LM4562 or LME49600/ 49720/ 49860, AD8066, OPA2227, THS4032 (my favourite, need´s 100nF cap between pin 4 & 8 for stabilization)
  
  
 Those are dual OpAmp´s and ready for use directly at the board. If using single ones, such as AD797, you will need 2 of them and a Brown dog adapter. Also have in mind if they are DIL/ DIP or for survace mounting. Surface mounting are more tricky to solder, and you will need an adapter also (if you´re not a solution handy man like me and MacGyver  see pictures below of some of my mod project´s)
  
 http://tangentsoft.net/audio/opamps.html
  
 It´s also possible to use a discrete OpAmp, such as Burson, John Hardy or Audio GD, but they´re very costy and bulky!
  
  
 / Mikael Markstrom


----------



## mikaelmark

Edit: Sorry, also the OPA627 is single and will ned an adapter for using 2 IC´s.
  
 Also, have in mind there are some single version OpAmp´s of those I listed, such as: OPA134 (instead for dual OPA2134), AD8610 (AD8620), THS4031 (THS4032) OPA1611 (OPA1612). There is some advantage, such as a bit better channel separation if using two single OpAmp´s, but the cost is a bit higher, it need´s more space at the board and more work to solder.
  
  
 / Mikael Markstrom


----------



## Laybar

Arriva il mio ...


----------



## nippon

New pictures for the thread!
  
 I matched the transistors and resistors... seems like no deal after all. Sounds allmost like my first clone.


----------



## nanchangbob

I wrote sometime ago about wanting to try to improve the performance of the BCL clone by improving on the power supply.  I've have done a lot of upgrades on my current unit and it really does sound great.  I changed the original input caps from Wima MP-10 to some Mundorf Zn pulls I bought and it seemed to improve the clarity a bit.  The Mundorf caps in the power supply also helped a little.  But the biggest upgrade was my DAC I moved from the ODAC to an Arcam rDac and the improvements were immediate and unmistakable. 
  
 Now I'm going to try changing the power supply to a shunt regulated low voltage power supply by Salas at Diyaudio.  It measures very low noise.  I've attached a picture with the different power supplies that it was up against.  I don't have a distortion analyzer so my observations will be subjective but I will give my honest assessment.


----------



## Laybar

I've finally finished


----------



## mikaelmark

Finished with the new power supply with changed voltage regulator? Any conclusions about the final sound?


----------



## nanchangbob

Sorry about taking so long to get back.  I ran into an issue.  I can use my shunt PS on either the positive or negative but not both at the same time.  Let me explain!  When I hook up the positive or negative alone it works fine on that channel but if I hook both up at the same time it blows a 1.25 A fuse.  I'm not sure why it does this as the original design only uses around 145ma per channel and and I've been testing the PS with over a 200ma load on each channel without any issues.
  
 I haven't give-up on this idea.  I ordered a new pcb for about $4 and I will build it up and play with it.  My current set-up is working good and I don't want to tear it apart and break it.
  
 I just built a Millet Maxed with BJT's and it's sounding very good and have The Wire and Marsh Headphone amp waiting.  Half of the fun is the building for me.  But I do love listening as well.
  
  I will post the results.  If someone has a theory of why it's drawing so much current with both the positive and negative supplies hooked up I would like to understand this problem.


----------



## nippon

Hi,
 where did you connect the new PS? Have you removed all parts of the old one? Don't be shy and post some pic of your wiring.


----------



## nanchangbob

I removed the large power supply caps C7 and C8 the two regulators and R9 and R10 I put the + and - voltages on the corresponding pins on the empty regulator pins and then put the grounds on the grounds.  Did I miss something?  I wanted to try it after pulling all the power supply parts but thought it would be easier just to try it on the new board I ordered.  Thanks for any input!


----------



## nanchangbob

I received the new PCB and started populating already.  I need to go tomorrow and pick-up a few things.  The new board is a bit smaller but seems fine other than that. It cost about six dollars shipped.
 I have damaged builds by doing mods in the past and given myself extra work.  I will play it safe this time.  I'm also going to pick-up some fuses that are slightly bigger.  I have a feeling that everything is okay and just draws more current on start-up than I am calculating.  I need to work this weekend so it may take a little while to finish.


----------



## nanchangbob

I built the new pcb and tested it and it has the same issue of over current.  I believe when the PS grounds are tied together on the PCB it causes a direct short on the transformer. The transformer was shaking a bit. I will buy a couple of cheap 15v transformers and I believe all will be fine.  When I hooked up first the neg supply it worked fine. Then I hooked up the positive supply side and it was fine. But together its a no go situation.  I'm just wondering if uses a capacitor and or resistor as a ground lift would work?


----------



## penmarker

Saw someone selling the Littlecube Premium in a local forum for MYR500 (about 180USD) and got interested, found this thread. Color me interested, subbed.
  
 **edit
 Some questions, how does it fare with sensitive cans? I have the JVC HA-S500 that's rated at 32ohm, 106db/1mw and upcoming Rockjaw Kommand rated at 16ohm, 110db/1mw. I have another Goldring DR150 but that's not much of a concern.


----------



## nanchangbob

I learned something today.  I picked-up a 0-15, 0-15 transformer and replaced thee 15-0-15 and the problem has been corrected. The two sides are truly separate. On the 15-0-15 it had three wires.
  
 Now I need to leave for two straight weeks of work.  I will try to  replace the power supply on the lovely cube again and do some listening tests.
  
 Penmaker- It drives my 35 ohm Hifiman cans fine, but I still prefer the Sennheiser HD-600's with it.


----------



## penmarker

nanchangbob said:


> I learned something today.  I picked-up a 0-15, 0-15 transformer and replaced thee 15-0-15 and the problem has been corrected. The two sides are truly separate. On the 15-0-15 it had three wires.
> 
> Now I need to leave for two straight weeks of work.  I will try to  replace the power supply on the lovely cube again and do some listening tests.
> 
> Penmaker- It drives my 35 ohm Hifiman cans fine, but I still prefer the Sennheiser HD-600's with it.


that's great!

I pulled from trigger on a pair of HD650 with a dead left channel, going to have a little fun with the lovely cube once I've checked what's wrong with them.


----------



## nanchangbob

Well I finally had a day off and finished my experiment with the Salas power supplies.  I tried it on the original board and had just a bit of noise.  I didn't want to deal with it so I finished the
 new board and swapped some of the parts over.
  
 I've been listening for almost six hours and I don't want to stop.  I wasn't expecting much from the power supply change.  The improvements were more pronounced than I would have guessed. 
  
 Using Flac files with Foobar on WASPI=PUSH output and an Arcam rdac.
  
 I starting hearing more information on my music.  Extension is improved on both ends. It just sounds more natural.
  
 The last couple of hours has been with my Hifiman HE-400's.  I always found them to be dark and therefore the have found duty on my wife's computer with the Objective 2.  They are sounding better than they ever did before.
  
 This amp sounds very good in it's original form and most people would never want to venture down this path.  For you more ambitious types you will be pleasantly surprised.


----------



## Habibelhabab

Hi
 Just wanted to share my build of a lovely cube.  I'm trying to get as close as possible to the linear SE original version.
 I have ordered this board from ebay seller minishow0328 for as little as 38 dollars (free shipping)
 http://stores.ebay.com/minishow0328/

 I received a beautiful, well made build with the exact layout of lovely cube (and original black cube)
 The pot was immediately changed to ALPS 50k and NE5532 to OPA2134 (asked the seller)
 I was very happy with the build quality, but as expected, a lot of components just demanded to be upgraded.
  
 At first testing I noticed immediately a volume imbalance between L and R.  Measured power supply output (at the LEDS): 14.71V and -15.06V.
 I have immediately changed the voltage regulators (probably fakes) with some new ones (together with all transistors and all PSU caps) and now voltages are 14.80 and -14.82 at the leds. Volume imbalance seems to be gone and I must say this thing sounds pretty god damn amazing out of the box.
 Allthough lots of caps had wrong values. (4x 0.1uF at rectifying section and 22nF opamp coupling and 22nF input cap bypass were all the same Rifa 0.047 630V - all the white ones in the picture) All transistors looked like fakes and even the opamp I'm not sure.
 Still I was completely blown away by the VAST improvement - this is my first dedicated headphone amp and previously I have been using the headphone outputs on my audio interfaces and mixer.  The soundstage!! The separation!! The fast bass response!!! And especially the non-fatiguing experience and airyness!!!
  
 Here are some pictures of my build as it is now, with case:
_board as received_:

_Some components already replaced, case built (case is an old Pioneer SA-420 amplifier cut down to size)_

_Will make better front plate for case later.  Notice I have built a wall outlet into the back (fused 2A) to charge portable sources directly from the unit._
_There are some benefits to a slightly oversized case _
  
 This week, I'm waiting for:
  
 -2x Mundorf Mlytic 4700uF 40V PSU reservoir caps (to replace Nover audio grade 10000uF 35V)
 -2x Mundorf MCap MKP 2,2 uF 250V (to replace both the 1,2 uF EPCOS 1000V and the 0,022uF WIMA MKP10 bypass that I have put there)
 -6x Panasonic FC-series 470uF 35V (to replace KME caps in PSU section and Opamp (RC filter?)
 -6x Panasonic FC-series 470uF 25V (to replace the former as experiment)
 -PRP metal film resistors all over (except PSU section)
 -2x LCR polysterene 22nF 63V (to replace wima MKP10 22nF that I have put there as Opamp coupling)
 -2x LCR polysterene 100pF 160V (to replace unknown capacitor in Opamp Low pass filter)
 -4x vishay roederstein kp1830 22nF 63V (to replace wima MKP10 22nF that I have put there as Opamp coupling)(or to try as input cap bypass)
 -4x vishay roederstein mkp1837 22nF 160V (to try as input bypass or opamp coupling)
 -2x vishay roederstein mkt1813 22nF 250V (to try as opamp coupling if polysterene gets too much heated)
 -Several opamps: LME4986, genuine OPA2134, LT1364
  
 I guess this should lift the performance to devine level 
 Any hints how to make the best use of these components are VERY welcome (espescially for roederstein caps)
  
 I would like to thank BlaBlaBla, Flukell, francisdemarte, ringer, aspenx and others VERY MUCH for sharing so much great info.


----------



## Habibelhabab

Forgot to share this in previous post:
 I have reworked the schematic with correct part naming (much easier to work with)


----------



## truly194

Do You know how sounds Lovely Cube with dac unit? It is with usb CM6631A and base on ES9023 dac.


----------



## penmarker

IMHO the amp is neutral so the issue would be pairing the DAC with the headphones.


----------



## namaiki

truly194 said:


> Do You know how sounds Lovely Cube with dac unit? It is with usb CM6631A and base on ES9023 dac.


 
 I have a Lovely Cube Premium AD (the one with the built in DAC) on the way in the near future. However, I only have a Apex Glacier and Leckerton UHA760 that I would be able to compare it with. I have no idea at all what to expect.


----------



## truly194

I hope that Lovely Cube has very nice applicate sabre dac - it can sound very nice


----------



## shaman11

Maybe I´m wrong, but when I read the reviews from the Le*mann site they talk about an Class A amp.
 When I look the pictures from this Lovely Cube I wonder why they use bipolar NPN and PNP transistors. when everyone knows that mosfets are less noisy than the old bipolar ones.
 For Class A you don´t need a (matched?) pnp and npn transistor, usually one transistor (pnp or npn) do the job but you can use more parallel to enhance the power output.
 So for me it seems that LC is a class AB Amp rather an Class A design and this is not exactly the same , Mr. Le*mann said ?
  
 How do you guys know, if the hongkong fab matched every bd139/bd140 per hand to find the right couple ? did someone of you take the LC in a audiolab and do some measurements (bode, thd etc etc.) ?
 Years ago, when I repair my minimoog Synth I waste hours of matching a bulk of transistors ...
 Maybe one of you can shed more light on this topic ?
  
 ( I found this thread after looking google images in search of a clear picture of the Le*mann pcb where I can see which transistors
 he used .. )
  
 cheers
  
 M


----------



## namaiki

I'm not really a technical person, but from what I recall it is possible to "bias into Class A" so I guess it may not be in Class A in stock configuration?
  
 Received my Lovely Cube Premium AD with built in DAC this morning. Postage to Australia was only 4-5 days.
  
 Just got home from work so I haven't had a good listen yet, but I can confirm that there is not any channel imbalance at low volume which is the thing that I was really most worried about. (You might notice that my last two amps have stepped volume. I nearly went for a stepped attenuator which is an option, I believe, instead of the stock volume pot) Still, there is no channel imbalance in the pot at any point that I can detect so I am extremely happy about that!
  
 edit: The PRaT coming from this thing is great. It has a pleasant delicate treble which is great for acoustic instruments and especially drums. Snappy and decent amount of space.  Vocals are sweet sounding and bass is good. I almost hate to say it because I don't usually care about this kind of thing, but the volume knob really has a really nice feel.


----------



## shaman11

so everybody seems happy with this project regarding biasing, matching or nothing at all.
 so its worth to try this LC and it doesn´t matter if its a Le*mann or not 
  
 all right
  
 I will try this for myself.
 First I was curious about hongkong tec. but all folks here are happy with the result.
 and if not they upgrade it with more and more expensive parts.
  
 I wonder why they build the transformer so near to the Line Inputs. Normally you avoid this with carefully audio design.
 The magnetic fluxlines induce hum to this lines.
 Its better to leave the ac/dc parts outside of the amp or shield it with nonferrous materials (like the multimediaboxes in the 90ies)
  
 M.


----------



## Laybar

how do I post pictures?


----------



## namaiki

Click the following icon and upload your pictures, or upload your pictures elsewhere and paste the link in your post.


----------



## penmarker

You need to have more posts to be allowed to post pictures sorry.


----------



## Tribbs

shaman11 said:


> I wonder why they build the transformer so near to the Line Inputs. Normally you avoid this with carefully audio design.
> 
> The magnetic fluxlines induce hum to this lines.
> 
> ...



 

I am under the impression the toroidal transformer alleviates stray magnetic flux with an 8:1 reduction of radiated magnetic field over an equivalent rated EI transformer.

"The advantage of the toroidal shape is that due to its symmetry the amount of magnetic flux that escapes outside the core (leakage flux) is minimum, therefore it radiates less electromagnetic interference (EMI) to nearby circuits or equipment."

http://en.wikipedia.org/wiki/Toroidal_inductors_and_transformers

From elsewhere:

"Due to their physical structure, toroidal transformers tend to be quieter (especially in terms of 60 Hz noise) and they are more efficient.

"The efficiency part means that a smaller tranny can do the job of a larger one, making them useful for rack gear and things that need to be packed into smaller spaces.

"Due to the shape of toroidal transformers, there is some inherent common-mode cancellation of radiated EMI. In fact, once installed, they can be rotated in place (while listening to the circuit) until the noise is minimized. There's sort of a 'notch' where self-cancellation is maximized.

http://www.electricalaudio.com/phpBB/viewtopic.php?f=5&t=48683#p1093089


----------



## penmarker

The Lovely Cube circuitry is well built. Recently I lost my laptop charger (again) and had to resort with an aftermarket adapter. It's probably a little faulty or not well made, so I can feel some current leakage on the aluminium keyboard surface when I run my finger across it. If its plugged into the Lovely Cube, the leakage disappears. It doesn't matter if it's connected via the 3.5mm jack or through the Aune T1 as a DAC, it helps with the leakage.
  
 Or maybe its a really simple fix, I don't know, I'm no electrician lol.


----------



## Tribbs

I've read much discussion earlier in this thread, and elsewhere, regarding replacing the LM317T/LM337T voltage regulators. But no one has mentioned using the Belleson Superpower regulators SPJ17/SPJ79 www.Belleson.com

Datasheet http://www.belleson.com/download/Superpower_datasheet.pdf

Anyone tried these regulators in the LC or other amp circuits?


----------



## nippon

Quote from the website of the "superpower":
  
 SPJ78, specify voltage [note that standard LM78xx can be used]... as also for SPJ79...
  
 Moneyburner detected! You can easily DIY a really nice power supply for less!


----------



## ervstil

I have a "original" Lovely cube with a strange problem. It has rather loud 50 hz hum and buz. It is intermittent, some times it is there an some times not. It is always the same level and goes from 0 to 100%, never in between. It is not affected by the pot position, not related to the input (shorted input makes no difference). The regulators are functional genuine ones, the main PS caps are ok. Does anyone have the same problem or does anyone have any ideas?


----------



## shaman11

check the diodes (wrong direction ?)
 cold solder points ?
 check this with an ohm meter and check the diodes off the pcb with the meter.
 move the headphone cable, the audiocables and look if the problem is gone ? if yes take a look to this solder joints.
 check the line in cables around the toroid transformer .. is the hum comming and going ?
  
 cheers.


----------



## ervstil

Thanks for the reply!
  
 Last night i solved the puzzle at last. I have checked all the usual suspects, including the suggestions above every thing was OK. I changed my 627 op amps for another pair. Same thing. Then i changed to a genuine opa2134 in dil package. Dead silent! As it turns out the opamp adapter functioning as an antenna and my  R-core transformer induced hum right in the feedback loop. I verified this by adding a "class a bias socket" and thing got really hummy. I have ruled out this before because i tried different shields and positions of the transformer with absolutely no difference. 
  
 So last night i re-winded a 60 va 2x12v toroid to 2x16v. I also added a electrostatic screen and connected it to the star ground. It was a really tight fit and i have to isolate the center bolt because it tushes the top of the case. I did not expect a good result because of the size of the transformer, now  the input and output cables are really close.
  
 The result was near perfect! 99% of the hum is gone! I did not expect this kind of difference between r-core and toroid.  Strange because the hum problem was not so severe a couple of moths ago. The most surprising thing was the audible quality difference between my old 30va (probably closer to 20 va in reality) and the new 60 va.
  
 The sound is better in the whole register especially the bass. I have seen comment of this earlier in the forum but thought it was bs. Why would a class a regulated circuit sound better with a massively over sized transformer over a sufficient one? Well this one does.....
  
 I was also surprised how much better  the amp sounds with my assumed fake 627 compared with my genuine 2134. maybe they are genuine....
  
 After this success  i decided to to competently remove my good quality 2.5 uf input cap. another huge step up! even better bass and another "veil" removed. I do not understand why the original value is so low. Going from 1.8 uf to 2.5 was big difference, removing it completely was a greater step up. If you have a offset problem it is better to solve the problem instead of adding a cap.
  
 One last observation, disconnecting the audio ground from the chassis and mains ground really improved the hum situation, so i vill leave it out or try to find space for a diode bridge ground isolator, Nelson Pass style.
  
 That would be the last mod i will do to it as at soon will be retired. I only use my electrostatic headphones now, and when my dac is finished i have no use for a pre amp. And if i fire up my dynamic phones again i have my balanced "aleph h" that blows this amp away competently. Highly recommended, dirt cheap to build on a breadboard and no opamps. Look it up on diyaudio if you are interested. 
  
 B.R Christian


----------



## Faithless

After many SS amps i end up with LC Premium. 
For me its a awesome amp.
The OPAMP rolling also improves the sound and add a good tweaking juice.
Now i'm using the Audio GD OPA-Earth with great results.


----------



## findcount

the Lovely Cube can be ordered with a 2nd input, right ?
  
 by the way, anyone here compared the Lovely Cube to the Garage 1217 Project Polaris ?


----------



## Tribbs

ervstil said:


> [...]
> 
> Last night i solved the puzzle at last. I have checked all the usual suspects, including the suggestions above every thing was OK. I changed my 627 op amps for another pair. Same thing. Then i changed to a genuine opa2134 in dil package. Dead silent! As it turns out the opamp adapter functioning as an antenna and my  R-core transformer induced hum right in the feedback loop. I verified this by adding a "class a bias socket" and thing got really hummy. I have ruled out this before because i tried different shields and positions of the transformer with absolutely no difference.
> 
> [...]




I wonder if a LME49720HA (in metal TO-99 can) opamp would have helped with shielding.
http://cdn.head-fi.org/e/e6/152x174px-e68c8761_LME49720HA-TO99.jpg
http://www.ti.com/lit/ds/symlink/lme49720.pdf

I use one with a TO-99 to 8-pin DIP adapter...
http://cimarrontechnology.com/to-99to8-pindipadapterpn020601-1.aspx

...class "A" biased with a TO-5 type heatsink for an extra margin of cooling.
http://www.mouser.com/ProductDetail/Aavid-Thermalloy/323005B00000G/?qs=HN%252bHT2FsGBlAuCmslBIVag%3D%3D


----------



## mikaelmark

So, now I´m almost finished with my two amps. It tooked some weeks to build them from skratch, but it was a joy. I only used high grade compontents, such as Elna Silmic II, Nichicon KZ Muse, Mundorf, Wima, OPA627AU, PRP9372, Polystyrenes, BYV27-200 with bypassing caps, Audyn True Copper with Teflon bypass caps, Dale 24 step volume attenuator etc.
  
 As I´ve built two amps, maybe someone want to buy one of them!?
  
 Just tell me if you´re interested or PM me.
  
 I also have s spare of most of the parts as it was cheaper per unit to buy bigger quantities, so I can also sell those if someone is interested.
  
  
 / Mikael Markstrom


----------



## Surlias

Can anyone comment on the quality of the DAC chipset used in the Lovely Cube Premium AD available for sale assembled at http://www.alicemagicbox.com/lasercollection/lovelycubepremiumad.html?
  
 The website lists the chipset as ES9023. I'm trying to decide between the Audio-GD NFB-11.32 and the Lovely Cube to drive a pair of Senn HD 650, and I'm wondering what kind of disparity in DAC quality there is between the two. The NFB-11 uses the ES9018. Initially I thought the 9023 must trump the 9018. Higher model number means better right? But then I've seen reports that the 9018 is actually a much higher quality chipset. So I'm just wondering if there really is that much of a difference, or if the 9018 is just more expensive without really being any better.


----------



## Tribbs

She's alive!

Finally completed my LC kit with the following component swaps and modifications:

1) Installed a Hammond (1182M15) 80VA Torroidal Transformer [barely fits] (w/500mA slo-blo fuse).
http://www.hammondmfg.com/1182.htm

2) Replaced C305 & C306 4700μF 50V capacitors with genuine United Chemi-Con (16M6799). 

3) Replaced LM317T/LM337T (Q301 & Q302) with genuine Fairchild regulators (58K8936/58K8937).

4) Replaced LM317T/LM337T R2 1KΩ resistors (R306 & R308 [R308 on schematic is mislabled] ) with two parallel Zener diodes (18C6023) in each position for lower resistance and safety.
http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/870#post_7930416
http://www.acoustica.org.uk/t/3pin_reg_notes1.html

5) Replaced the LM317T/LM337T Cadj capacitors, C308 & C311, with genuine Sprague 10μF tantalums (30C8841).

6) Replaced C103, C104, C203, C204, C313, C314, 470μF 25V capacitors with genuine Panasonic FC (80K8337).

7) Replaced C101,C102 & C201, C202, 1.5μF 200Vdc and 0.022 μF 600Vdc input caps, with SoniCap Gen I (cheap & good enough).
http://www.soniccraft.com/product_info.php/gen-sonicap-15-uf-200vdc-p-417
http://www.soniccraft.com/product_info.php/gen-sonicap-0022-uf-600vdc-p-404

8) Replaced opamp with genuine Texas Instruments LM4562HA with TO-99 to 8-pin DIP Adapter and TO-99 heatsink.
http://www.ti.com/lit/ds/symlink/lm4562.pdf

Worked perfectly on the first smoke test - and sounds great!

Thanks go out to the many "BlaBlaBla" posts earlier in this thread for sharing his technical knowledge, experiments, troubleshooting and suggested upgrades. Kudos!


----------



## sunneebear

All lies! I need picture proof!


----------



## Laybar

I can not get the pictures, appears Your account does not have the required permissions to access this page.


----------



## Laybar

I can not get the pictures, appears Your account does not have the required permissions to access this page.


----------



## francisdemarte

habibelhabab said:


> Forgot to share this in previous post:
> I have reworked the schematic with correct part naming (much easier to work with)


 
  
 Thanks! I've updated the first post with the correct schematics.


----------



## penmarker

laybar said:


> I can not get the pictures, appears Your account does not have the required permissions to access this page.


 
 You have low post count. Try uploading them to imgur.com perhaps until you're allowed to post pictures in the forums.


----------



## Tribbs

sunneebear said:


> All lies! I need picture proof!




Your post was my bad luck!

Today, I was going to take pictures. But, when I turned on the amp the 500mA mains slo-blo fuse blew. Replaced, and immediately blew the second one to. I don't have time to troubleshoot until next week. Any suggestions?

She was working fine for a total of about 3 hours.
Damn.


----------



## mikaelmark

One thing I tas noticed it that many people using the attached sockets with screws for connection of the wires in their amps - those sockets is the first thing I throw in the trash bin. Many are telling they use expensive Mogami wires, and then assembled them in the amp with plain steel sockets - the chain is not better then the weakest link!! It´s very preferable to solder the wires directly to the board. And for the difference in wiring, I don´t think there will be a huge difference between for example Mogami and standard ogygen free copper wires when using them so short in the amp.
  
 Another thing I struggling with for the moment, is to find high quality 1/4 inch/ 6,35 mm headphone sockets for soldering. I have bought several different types, but no one will be gold plated, and one person claimed his headphone sockets were made of copper, but when I get them, they were not goldy or copper. Just shiny blank so I´m not sure if they´re just steel or nickel. Or maybe they are made of copper, but are nickel or chrome plated.
 They are not magnetical, so at least that´s good.
  
 How important is it to use gold plated headphone connectors? I know gold plating are used to minimize the risk of oxidation.
  
 And do someone know where to buy gold plated stereo headphone sockets? I´ve found gold plated mono sockets, but they need to be stereo.
  
  
 / Mikael Markstrom


----------



## Tribbs

mikaelmark said:


> And do someone know where to buy gold plated stereo headphone sockets? I´ve found gold plated mono sockets, but they need to be stereo.




I think gold plated jacks are cheap - no brainer.

The gold plated jacks that came with my LC "deluxe' kit (deluxe kit no longer available) look like these:

Neutrik NRJ6HF-1-AU http://www.neutrik.us/en-us/plugs-jacks/slim-jacks/nrj6hf-1-au

In stock at Mouser:
http://www.mouser.com/ProductDetail/Neutrik/NRJ6HF-1-AU/?qs=sGAEpiMZZMv0W4pxf2HiV218T9lEUjXAMEGr3NewsmE%3d

Mounting hardware must be ordered separately:
NRJ-NUT-B (black plastic)
http://www.mouser.com/ProductDetail/REAN-Neutrik/NRJ-NUT-B/?qs=sGAEpiMZZMt%2fyfy0dIxWU3AAL6z7x4Ur
NRJ-NUT-MK (metal knurled)
http://www.mouser.com/ProductDetail/Neutrik/NRJ-NUT-MK/?qs=%2fha2pyFadujZed****6FBPxlzcU%2fmwJCCmOJKMSfQcc%3d
NRJ-NUT-MS (metal)
http://www.mouser.com/ProductDetail/Neutrik/NRJ-NUT-MS/?qs=%2fha2pyFadujZed****6FBEfQiNgjNWY4S3DlgOz5xpIxeFS12gEZHQ%3d%3d
NRJ-NUT-R (red plastic)
http://www.mouser.com/ProductDetail/Neutrik/NRJ-NUT-R/?qs=%2fha2pyFadujZed****6FBDcoj1wQT3%252b0eSZ3usZUCC4%3d
NRJ-WB (black washer)
http://www.mouser.com/ProductDetail/REAN-Neutrik/NRJ-WB/?qs=sGAEpiMZZMuur7c7MCGU2IptMe4770rm


----------



## mikaelmark

Thank´s for your teply, Tribbs!
  
 It´s a shame I can´t found those gold Neutrik here in West europe, shipping from Mouser is about $25.
  
 It seem´s the shiny connectors that´s not gold plated is made of bronze with tin and selenium(?) plating:
  
 http://www.ebay.com/itm/2x-GENUINE-JACK-PHONE-CONNECTOR-NEUTRIK-NYS216-1-4-6-35mm-STEREO-/280870616292?pt=LH_DefaultDomain_186&hash=item4165317ce4
  
  
 / Mikael Markstrom


----------



## Tribbs

mikaelmark said:


> Thank´s for your teply, Tribbs!
> 
> It´s a shame I can´t found those gold Neutrik here in West europe, shipping from Mouser is about $25.
> 
> ...




$25 shipping from Mouser auf Deutschland? - OMG!

Is this jack for the Lovely Cube's PCB?
The part you linked to on eBay is too large.

You need a "Slim Jack" to fit on the Lovely Cube PCB.
http://www.neutrik.com/zoolu-website/media/download/2842/Drawing+NRJ6HF-1

Is this the correct part for you?
http://www.mouser.de/ProductDetail/Neutrik/NRJ6HF-1-AU/?qs=R5cXQUTKuHUV%2FlSznFp3HA%3D%3D

How many do you need?


----------



## mikaelmark

tribbs said:


> $25 shipping from Mouser auf Deutschland? - OMG!
> 
> Is this jack for the Lovely Cube's PCB?
> The part you linked to on eBay is too large.
> ...


 

 Yes, that is the correct part!
  
 For me, the size/ height is not a big deal, as I will build my own case after I has finished the amp.
  
 It´s enough for me if I can get four pcs of these headphone/ sockets. Is it possible to buy from you maybe? I can pay with Paypal, if you have an account.
  
  
 Grateful regards: Mikael Markstrom


----------



## Tribbs

mikaelmark said:


> Yes, that is the correct part!
> 
> For me, the size/ height is not a big deal, as I will build my own case after I has finished the amp.
> 
> ...




PM sent!


----------



## mikaelmark

tribbs said:


> I think gold plated jacks are cheap - no brainer.
> 
> The gold plated jacks that came with my LC "deluxe' kit (deluxe kit no longer available) look like these:
> 
> ...


 
 I realized those gold plated connectors from Neutrik are made of bronze.
  
 As gold is one of the best metals to use as plating (due to it´s resistance to oxidation and quite good conductor behavior - only rhodium will be better against oxidation), it should be better then connectors using nickel or tin/ selenium plating. But as those tin plated connectors are made of copper, I think those will be much better suited as copper is a way better conductor then bronze. And for the conduction of the tin/ selenium, I don´t think it will be so much a grading down as the plating is so thin.
  
 Also, when I take a deep look at a Neutrik connector in my Corda Swing amp, it´s gold plated - but not all of the three connector´s seems to be gold. Strange!
  
 So Tribbs; Thank you very much for your kindly offer for those Neutrik´s, but I think I will stay with the copper one´s I already have.
  
  
 / Mikael Markstrom


----------



## Tribbs

mikaelmark said:


> I realized those gold plated connectors from Neutrik are made of bronze.
> 
> As gold is one of the best metals to use as plating (due to it´s resistance to oxidation and quite good conductor behavior - only rhodium will be better against oxidation), it should be better then connectors using nickel or tin/ selenium plating. But as those tin plated connectors are made of copper, I think those will be much better suited as copper is a way better conductor then bronze. And for the conduction of the tin/ selenium, I don´t think it will be so much a grading down as the plating is so thin.
> 
> ...




Silver is the best conductor even better than copper or gold. Of course solid silver and solid gold is not economical. Additionally, they are not strong enough in a pure form to resist metal fatigue in mechanical contacts such as jacks. Which is the reason for the use of bronze (88% copper and 12% tin) and other metals (plated steel) for mechanical strength. But in audio frequency, a relatively low frequency, the electrical current doesn't flow primarily on the conductors surface (skin effect) as it does with much higher (radio/microwave) frequencies. So, gold plating in audio applications is primarily a benefit as a non-oxidizing contact surface. In addition to gold plating, silver plating is also available. But, silver will tarnish over time, as will exposed copper and bronze, so conductivity may suffer. This is why gold is favored as a plated contact surface.

In any case, I don't think it is of great consequence except for your own satisfaction - I understand this 

It's my pleasure - all the best!


----------



## mikaelmark

blablabla said:


> +/-21V is OK.
> 
> You will always have 14V on output because zener diode doesn't allow anything over 13V and LM regulation voltage is 1.25V. (13V+1.25V=14.25V). You can put there 2x36V transformer and voltage on output will be still around 14V. Zener diode replaced R2. Since you have 18VAC RMS transformer and output (after regulators) is less than 18V DC, you have big reserves. Probably regulators will heat more, but voltage will be stable (up to LM spec) because it is far above safety margin (Vtrans*1.25 - Vout(reg) = 2V).
> 
> I am glad that you are satisfied. Sometimes there will be good results and sometimes bad. When you do something on your own, you always learn something new.


 
 What resistor could be replaced with Zener diodes? You wrote R2 near LM317 and LM337, but I can´t found any resistor named that.
  
 So, what value do the replacable R2 -resistor has, and is it only one resistor to replace with Zener? And should it be one or two Zener in parallell?
  
  
 Best regards: Mikael Markstrom


----------



## Tribbs

sunneebear said:


> All lies! I need picture proof!







Replaced the 500mA slow blow fuse with a 1A. Reading up on the web about toroidal transformers (mine is 80VA!) it turns out that on power-up the initial surge to the toroid was causing my fuse to blow. After much trouble-shooting and voltage measurements I realized nothing was amiss. So, I simply increased the fuse rating. Dozens of power cycles later no more blown fuses - all is well.

Currently employing a pair of single channel LME49990MA opamps on a Brown Dog adapter - Swwwweet!


----------



## sunneebear

You've inspired me to get off my butt and revive my LC...tomorrow...maybe.  I'm a member of Procrastinators of America.


----------



## Tribbs

mikaelmark said:


> blablabla said:
> 
> 
> > +/-21V is OK.
> ...




You are right. There is no "R2" resistor on the LC schematic or PCB.
The "R2" resistor to which Bla Bla was referring is relative to the LM voltage regulator notes at the following site:
http://www.acoustica.org.uk/t/3pin_reg_notes1.html
Quote in middle of the page, "_replace R2 with something like a zener diode_"

If you follow Bla Bla's method you will need four Zeners. Two parallel (piggy-backed) Zeners per each replaced 1K ohm resistor.
See photo in my next post. You can simply measure their resistance to be certain you have the correct resistors.

The cathodes of the Zener diodes should be oriented towards the higher voltage potential.
Zener pair one towards +15V, and Zener pair two towards 0V (ground), 

This end, the anode, should be oriented towards the lower voltage potential, 0V and -15V, respectively. 

See Bla Bla's diagram in my next post.

Fairchild Part No.: *BZX85C13*
Mouser Part No.: 512-BZX85C13 
Newark Part No.: 18C6023
Digi-Key Part No.: BZX85C13-ND

:basshead:


----------



## Tribbs

Note each Zener diode pair's cathode orientation...


Look at Bla Bla's diagram #1 below...


So, the R2's would be R306 and R308 on the LC's PCB shown below.

The cathodes of the two parallel Zener diodes replacing R306 should be oriented towards C307.
The cathodes of the other two parallel Zener diodes replacing R308 should be oriented towards R304.

:atsmile:


----------



## Tribbs

sunneebear said:


> You've inspired me to get off my butt and revive my LC...tomorrow...maybe.  I'm a member of Procrastinators of America.


----------



## mikaelmark

tribbs said:


> You are right. There is no "R2" resistor on the LC schematic or PCB.
> The "R2" resistor to which Bla Bla was referring is relative to the LM voltage regulator notes at the following site:
> http://www.acoustica.org.uk/t/3pin_reg_notes1.html
> Quote in middle of the page, "_replace R2 with something like a zener diode_"
> ...


 


> Thank you very much for this explanation!





> So, I guess the idea of using paralell Zeners are because of the low wattage they can handle. But if using a higher wattage Zener, do you think it´s enough with only 2 pcs (just single 1+1, not paralell 2+2), such as this 13 Volt 5 Watt 1N5350B:





> http://uk.farnell.com/multicomp/1n5350b/diode-zener-5w-13v-5-do-201ae/dp/17980031N5350B%20DIODE,%20ZENER,%205W,%2013V,%205%,%20DO-201AE



 As for the 1 A fuse instead of 500 mA, I also had a problem when I used a high Wattage toroidal transformer, so the fuse blowed up when powered on. When I replaced it with higher value (slow, of course), everything was fine. But where is the fuse in this amp? The only fuse I can see is the two yellow heat fuses PPTC at the incoming 15, 0, 15 VAC? I guess there should be a glass (or even better a AHP) fuse in the case, at one cable of the incoming 115/ 250 VAC after the IEC? But how high value dare the fuse have, is 2 A Slow too much?
  
  
 Best regards: Mikael Markstrom


----------



## mikaelmark

tribbs said:


> Note each Zener diode pair's cathode orientation...
> 
> 
> Look at Bla Bla's diagram #1 below...
> ...


 
 I assume the 200 Ohm resistor for R306 and R308 is only a mod when stay with the 1K1 resistors, and should not be used if replaced with Zener diodes, right? Is it two different mod´s?
  
 / Mikael Markstrom


----------



## Tribbs

habibelhabab said:


> Forgot to share this in previous post:
> I have reworked the schematic with correct part naming (much easier to work with)




It's still wrong!

R307 should be labled "R308" (=1.1K ohm)
R308 should be labled "R307" (=100 ohm)


----------



## Tribbs

mikaelmark said:


> I assume the 200 Ohm resistor for R306 and R308 is only a mod when stay with the 1K1 resistors, and should not be used if replaced with Zener diodes, right? Is it two different mod´s?
> 
> / Mikael Markstrom




WHAT 200 Ohm resistor???

The two resistors to be replaced with zener diodes are 1.1K ohm resistors: R306 and R308 as designated on the PCB of the Lovely Cube amplifier.


----------



## mikaelmark

tribbs said:


> WHAT 200 Ohm resistor???
> 
> The two resistors to be replaced with zener diodes are 1.1K ohm resistors: R306 and R308 as designated on the PCB of the Lovely Cube amplifier.


 
 At number 2 and 3 at the drawed schematic, it say´s there should be trimpots at 200 Ohm with the 1K resistosr, so they will be equal to 1K1. But I guess this will not refer to the Zener mod!?

  
  
  
 / Mikael Markstrom


----------



## Tribbs

No! As far as I know, you can't have both modifications.
Either #1 OR #2 and #3.

If your DC offset is <20mV you don't need #2/#3.


----------



## penmarker

I've just gotten around opening my Lovely Cube Premium and I see that some components aren't the same as the others. The op amp is also different which is the LM 4562NA.
  
 **added: How will the LM4562NA fare with a dual OPA627AP?


----------



## mikaelmark

penmarker said:


> I've just gotten around opening my Lovely Cube Premium and I see that some components aren't the same as the others. The op amp is also different which is the LM 4562NA.
> 
> **added: How will the LM4562NA fare with a dual OPA627AP?


 
  


penmarker said:


> I've just gotten around opening my Lovely Cube Premium and I see that some components aren't the same as the others. The op amp is also different which is the LM 4562NA.
> 
> **added: How will the LM4562NA fare with a dual OPA627AP?


 
 I hav´nt tried the LM4562, altough I´m having two pcs in my shelf.
  
 As far as I know, they are high end, at the same level as OPA627, even the LM4562 is much cheaper. It measuring will is used in some high end equipment such as the newer version of the Benchmark DAC1.
  
 It should be well suitied for this headphone amp. The only downside may be it can feel a bit clinical/ sterile/ boring and not so much musical soul.
  
 But both OpAmp´s are of much higher grade than the standard OPA2134 used in BCL - that one also measuring well but some say it sound like putting the head in a bucket; a narrower sound stage.
  
 As the OpAmp is the heart in an amp, it´s a personal option what sound the best - it also affect the sound more than the DAC-IC in a DAC. My personal favourite playing in the same league as LM4562 and OPA627 (they should even be a bit better), that I´ve used widely is the TI THS4032 or two mono THS4031 with 0,1uF caps soldered to them so they will not oscillate. They´re really nice!
  
  
 / Mikael Markström


----------



## mikaelmark

blablabla said:


> Do not plug in your headphones. This offset is almost to big for speakers!
> 
> 1. Pull out tantalum capacitors and measure Vout. Regulator can work without Cadj (tantalums) and LM will show good Vout voltage if tantalums were bad. If you have multimeter in the same time, you can measure capacitance on pulled out tantalums. But watch out for polarity. Tantalum capacitors will blow of if there is reverse polarity for more than 2% of nominal value.
> 
> ...


 
  


> So if using a higher wattage zener, may it be enough with only 2 zener diodes (just single 1+1, not paralell 2+2), such as 13 Volt 5 Watt 1N5350B, or are they not gonna work fine in this amp replacing the standard 1K1 resistors?





> http://uk.farnell.com/multicomp/1n5350b/diode-zener-5w-13v-5-do-201ae/dp/17980031N5350B%20DIODE,%20ZENER,%205W,%2013V,%205%,%20DO-201AE





>





> / Mikael Markstrom


----------



## penmarker

mikaelmark said:


> I hav´nt tried the LM4562, altough I´m having two pcs in my shelf.
> 
> As far as I know, they are high end, at the same level as OPA627, even the LM4562 is much cheaper. It measuring will is used in some high end equipment such as the newer version of the Benchmark DAC1.
> 
> ...


 
 I contacted the previous owner earlier today and he confirmed that he swapped the stock OPA2134 to the LM4562 and forgot to switch it back. It sounds perfectly fine by me. I love soundstage but have a hard time discerning them properly. Up until now, all of the music I've heard from earphones/IEM/headphones sounded like they were a wall of music from the front instead of a parabolic shape (_left and right sounds sound far away but gets closer to my face as they come to the middle, as opposed to front channel being further away_). I've tried all setups from low to high end, it's just not very realistic to me even binaural sounds. Maybe I'm putting my expectations too high but that's how I've been hearing things.
  
 The amp is fantastic, paired it up with an AK240 playing The Eagles DSD with the HD650 sounds heavenly. I really can't believe the quality of sounds I'm getting from this unit, and I got it for only around US$100 used. It was in perfect condition too.


----------



## mikaelmark

penmarker said:


> I contacted the previous owner earlier today and he confirmed that he swapped the stock OPA2134 to the LM4562 and forgot to switch it back. It sounds perfectly fine by me. I love soundstage but have a hard time discerning them properly. Up until now, all of the music I've heard from earphones/IEM/headphones sounded like they were a wall of music from the front instead of a parabolic shape (_left and right sounds sound far away but gets closer to my face as they come to the middle, as opposed to front channel being further away_). I've tried all setups from low to high end, it's just not very realistic to me even binaural sounds. Maybe I'm putting my expectations too high but that's how I've been hearing things.
> 
> The amp is fantastic, paired it up with an AK240 playing The Eagles DSD with the HD650 sounds heavenly. I really can't believe the quality of sounds I'm getting from this unit, and I got it for only around US$100 used. It was in perfect condition too.


 
 Nice!
  
 As your LM4562 are socket mounted, you can always try with different OpAmp´s and see what you prefer.
  
 I notice you´re from Malaysia, so you maybe can get OpAmp IC´s easier than here in the west.
  
 Then when you are satisfied, I suggest you consider to solder the OpAmp as sockets are not the best for high end audio - I´m happy to see the incoming audio signal are soldered without sockets. And the 4 pcs 10 Ohm Dale CW-2B may get some bad sound if they´re not non-inductive as the NS -serie Ayrton Perry.
  
 Also, be aware of that kind of 1/8 to 1/4 adapter, as it can really degrade the sound if the quality of it is poor.
  
 I will not scary you, but those things are what I notice can reduce the sound quality.
  
  
 / Mikael Markstrom


----------



## penmarker

I'm interested in getting the Audio-GD Moon opa, but someone pointed out how they measure badly. I'd attach the link here but I'm on my phone.

The 1/4 inch adapter is good quality so it's fine. There is a local person selling a bunch of op amps including Sun, Moon, Earth, dual 627AP, and 627BP.


----------



## mikaelmark

penmarker said:


> I'm interested in getting the Audio-GD Moon opa, but someone pointed out how they measure badly. I'd attach the link here but I'm on my phone.
> 
> The 1/4 inch adapter is good quality so it's fine. There is a local person selling a bunch of op amps including Sun, Moon, Earth, dual 627AP, and 627BP.


 
 Measures are one aspect, that can tell if a IC etc make good sound quality - but today´s OpAmp´s, DAC´s etc are mostly so high grade the small differences in THD, SN ratio, dynamic etc a normal hearing person can´t be heard any difference between them.
 Then we have the listening qualities, and they will differ between person´s and what music listening to, some prefer other qualities then some do; some like a warm sound, maybe with a heavy bass, as other´s prefer a clean sterile sound with a lot of treple. Some want big soundstage with good instrument separation as other´s just prefer a "right in the face" sound.
  
 So it´s difficult to say what OpAmp is the best, but just google for the Texas Instrument´s THS4032 (stereo) or THS4031 (mono), as many people like it so much and also prefer it above the OPA627 - I have implement it in many of my gears as CD-player´s, Squeezebox, DAC´s, headphonea amp´s, X-Fi sound card´s etc, and like it a lot!
  
 But if you want seriously good sound quality and want to mod your Lovely Cube, I suggest you first of all consider to change the two blue cubed DC blocking cap´s for the incoming signal and maybe also the parallell yellow at side of them, as they may affect the sound a lot. You can also replace them with good copper or silver wire´s, if you are sure you will not have too high DC current to your headphones. In my amp´s, I have used Audyn True Copper 1,5 uF (about $80 pair) parallelled with Russian Teflon FT-1 (about $4 pair). Bought some extra of both of them to get a lower price, so I can sell if you are interested.
  
 Then consider to change the blue polarized electrolyt´s, at least the two nearest the OpAmp, as the signal will go through them. I used Elna Silmic II for those, and four Nichicon Muse KZ for the power supply (altough I know many use the popular Panasonic FC).
  
 You can also replace the two big 4700 uF cap´s to better one´s, I used 10000 uF Mundorf M-Lytic (about $30 pair), wich I also have some extra spare to sell.
  
 All depends on how much you´re willing to invest for your good sound and what headphones you are using (my phones are Sennheiser HD800, HD600, recabled HD650 and AKG 702).
  
  
 / Mikael Markstrom


----------



## penmarker

Thanks Mikael, you're the real deal. Unfortunately I'm putting my purchases on hold for now. Just secured myself a new job and I'd love to pay off all my loans and debts first. 
  
 I have to say, even without modding anything, the amp is amazing. I'll read through the mod logs other users had tried, especially the improvements from capacitor upgrade. Just curious, what other amps do you currently own and use to drive your headphones?


----------



## mikaelmark

penmarker said:


> Thanks Mikael, you're the real deal. Unfortunately I'm putting my purchases on hold for now. Just secured myself a new job and I'd love to pay off all my loans and debts first.
> 
> I have to say, even without modding anything, the amp is amazing. I'll read through the mod logs other users had tried, especially the improvements from capacitor upgrade. Just curious, what other amps do you currently own and use to drive your headphones?


 
 Ok, I see!
  
 I own a Harmony Design Ear90, Meier Audio Corda Swing (modded), Pro-Ject Headbox II (modded to portable w battery), Earmax Pro w tube, Chu Moy battery/ portable (self built), Lovely Cube (self built and sold) + a lot of DAC´s (altough a bit off topec - self builded or modded. Below a AK4399 DAC with OPA627AU, modded with Mundorf MLytic, Elna Silmic II, Panasonic FM and soon with all Holco resistors, sounds better than DAC Magic ).


----------



## mikaelmark

mikaelmark said:


> Ok, I see!
> 
> I own a Harmony Design Ear90, Meier Audio Corda Swing (modded), Pro-Ject Headbox II (modded to portable w battery), Earmax Pro w tube, Chu Moy battery/ portable (self built), Lovely Cube (self built and sold) + a lot of DAC´s (altough a bit off topec - self builded or modded. Below a AK4399 DAC with OPA627AU, modded with Mundorf MLytic, Elna Silmic II, Panasonic FM and soon with all Holco resistors, sounds better than DAC Magic ).


 
 If I will line them up in order (best to worst), it will be like this: Earmax Pro (deapest bass), Corda Swing, Pro-Ject Headbox II (same OpAmp as Swing - THS4031/2), Harmony design Ear90, Chu Moy.
  
 I have also owned a Grado RA1 -clone, that is now sold.
  
 I will be back any day when my new LC is ready and up for listening, how it compares to my other amp´s!
  
  
 / Mikael Markstrom


----------



## mikaelmark

May this R-Core transformer at a total of 30VA be fine for LC? It say´s it will give 0,5A for 15V, so maybe it will be less than LC will need?
  
 http://www.ebay.com/itm/1pcs-NEW-220V-115v-30W-R-Core-Transformer-for-preamp-9V-2-15V-2-/301543117001?
  
  
 / Mikael Markstrom


----------



## mikaelmark

Also, when I looked at LC -homepage, he use a EMI noise filter before the transformer.
 Is this a good idea, to lower the noise?
  
 / Mikael Markstrom


----------



## Tribbs

The LC "standard" toroid, the Telema 70063K, has a 2 x 15V output rated for 832mA each.
So, your R-core is a little short at 2 x 500ma. I would look for at least a 30VA.

Do you need both 9V and 15V outputs? There are many ebay listings for 30VA R-core with only 15V outputs.
http://www.ebay.com/itm/115V-230V-30W-R-Core-Transformer-15V-15V-for-Headphon-amp-preamp-/221703835182/

In regards to the mains filter, an R-core will give you some filtering. Better than a toroid. Adding the socket filter won't hurt but it's not a miracle if you have very noisy mains. I use a separate mains filter. Something like this http://www.tripplite.com/surge-protector-isobar-4-outlets-200v-240v-2m-cord-680-joule~EURO4/


----------



## mikaelmark

tribbs said:


> The LC "standard" toroid, the Telema 70063K, has a 2 x 15V output rated for 832mA each.
> So, your R-core is a little short at 2 x 500ma. I would look for at least a 30VA.
> 
> Do you need both 9V and 15V outputs? There are many ebay listings for 30VA R-core with only 15V outputs.
> ...


 
 I have now get a toroid with 2 x 15V at 200VA, with a slow 2A fuse and then I installed an EMI-filter (like that one in the picture). I unmount the metal housing from it, and solder it directly at the wires and mounted everything in an power supply case for PC. I´m also gonna mount the LC in another power supply case, with a power cable between them (made for 115V/230V): http://www.8audio-mall.com/7-layers-triple-screens-cable-for-diy-audio-power-cable/
  
  
 / Mikael Markstrom


----------



## mikaelmark

Altough I´m not quite finished with the amp, I´m thinking of let my next LC be battery-driven for portable use.
  
 This gonna let me skip all the components in the power supply, as I will connect the battery directly to the 15VDC  in (marked green).
  
 Everything in the marked area below can be excluded; the heat fuses, rectifier diods, four caps, two filtering caps, resistor R301 - R304. But I guess the resistor R305 - R308 (includes the eventually Zener mod) must be left.
  
 Am I right?


----------



## Tribbs

Why do you want to use batteries?

What will happen when the battery drains down and the voltage goes below +15Vdc to the input of the LM317 regulator?

How will you supply -15Vdc to the input of the LM337 regulator?


----------



## penmarker

I assume battery provides a cleaner power supply, much like how a power conditioner processes the power line before feeding to your amps/dacs/transports/etc.


----------



## mikaelmark

tribbs said:


> Why do you want to use batteries?
> 
> What will happen when the battery drains down and the voltage goes below +15Vdc to the input of the LM317 regulator?
> 
> How will you supply -15Vdc to the input of the LM337 regulator?


 
 I have already done this with another amp, a Pro-Ject Headbox II, and it´s to make it portabel use with a FiiO X5 player, but this amp only had a LM317 - not 337.
 When the battery drains out and the voltage are low, the sound will distort a lot and finally the sound level will be less.
  
 I assume R305 - R308 will take care of the -15 to LM337, or am i getting wrong?
  
 What are the 15VDC supposed for at LC? Is it to take get 15VDC out?


----------



## mikaelmark

Also the C210 seems to be involed for getting -15VDC to LM337.


----------



## PaulMC2

I picked up my lovely cube today in Vietnam - really please with it - something that drives my he-400's decently

Here is my bedside setup

Lovely cube premium
Fiio e18
Moto x (source)
HE-400

Wife had a pair of hd598's running off the second output


----------



## francisdemarte

mikaelmark said:


> I have already done this with another amp, a Pro-Ject Headbox II, and it´s to make it portabel use with a FiiO X5 player, but this amp only had a LM317 - not 337.
> When the battery drains out and the voltage are low, the sound will distort a lot and finally the sound level will be less.
> 
> I assume R305 - R308 will take care of the -15 to LM337, or am i getting wrong?
> ...


 
  
 I have no experience with this mod. Try it and let us know how it turns out. What type of battery are you planning on using to supply the 15V DC?


----------



## francisdemarte

paulmc2 said:


> I picked up my lovely cube today in Vietnam - really please with it - something that drives my he-400's decently
> 
> Here is my bedside setup
> 
> ...


 
  
 Nice! So which of you have the control of the volume


----------



## PaulMC2

Its on my side of the bed

I think thats my spending done for a while!


----------



## mikaelmark

francisdemarte said:


> I have no experience with this mod. Try it and let us know how it turns out. What type of battery are you planning on using to supply the 15V DC?


 
 I intend to use a battery pack with 13 AA 2000 mAh batteries in serie, it worked fine with for my earlier amp.
  
 If I want more listening time, I can use 2 pack´s in paralell.


----------



## mikaelmark

I have now asked a friend at my work about this project, as he is an old men with good know how in electrical - and he said it should be fine to drive the LC with battery connected after the rectifier diod´s. It will also be fine if connect the battery before the diod´s, but preferrable after (to 15VDC in).
  
 But the two big 4700uF (or in my case 10000uF) filter cap´s should be used.


----------



## mikaelmark

When connecting the 2x15VAC to the PCB, which two cables should be connected together to get 0VAC?
  
 In the LC diagram, it should be black and yellow. But when I measuring my toroid, I will get 0 Ohm between red-black and 0 Ohm between yellow-orange (as in the diagram), because those are connected in the same winding.
  
 So, is this the right way to - should´nt it be black-orange connected together for 0VAC instead?
  
 If connecting them wrong, I think it may generate some noise or interference to the power supply.


----------



## Tribbs

mikaelmark said:


> When connecting the 2x15VAC to the PCB, which two cables should be connected together to get 0VAC?
> 
> In the LC diagram, it should be black and yellow.




Correct! It is wired in series and in phase. (But, I don't think it matters.)




mikaelmark said:


> But when I measuring my toroid, I will get 0 Ohm between red-black and 0 Ohm between yellow-orange (as in the diagram), because those are connected in the same winding.




Which toroid transformer do you have?

According to the Talema 91230-P2S2 datasheet:

The DC resistance of the two secondaries should be about 1.4488Ω each.
The DC resistance of the two primaries should be about 46Ω each.

Check your meter's ohm range setting.

What happened with your battery experiment?


----------



## mikaelmark

tribbs said:


> Correct! It is wired in series and in phase. (But, I don't think it matters.)
> Which toroid transformer do you have?
> 
> According to the Talema 91230-P2S2 datasheet:
> ...


 
 Thank´s for your reply, Tribbs!
  
 I get the answer above from Stephen about this:
  
_"Talema Toroid 30VA 2x15V has 2 version,  input 220V and input 115/230V version.  When using input 115/230V version for 220V input, the 2 primary coils must be connected in series, i.e. red , black-yellow, orange , to become 15-0-0-15V.  As I remember, the DC resistance across each primary coil is about 1.5 ohms. I attach here the pdf information about these 2 talema toroids."_
  
 So, I assume I should also connect black-yellow for 0V, red as 15V and orange as 15V altough I have the only 230V version with two primary wires? Am I correct?
  
 There are 0 Ohm between red-black and 0 Ohm between yellow-orange. But no connection (infinity) between black-yellow. My DVM has autorange.
  
 About the battery project, first I have to finished up my LC I´m now up with - gonna test it any day now as I´ve just received my last Holco resistors, then I may try it with battery.
 Talema Toroid 30VA 2x15V has 2 version,  input 220V and input 115/230V version.  When using input 115/230V version for 220V input, the 2 primary coils must be connected in series, i.e. red , black-yellow, orange , to become 15-0-0-15V.  As I remember, the DC resistance across each primary coil is about 1.5 ohms. I attach here the pdf information about these 2 talema toroids.


----------



## mikaelmark

Stephen seem´s to give wrong information, as he also send me a second mail:
  
_"Talema Toroid 30VA 2x15V has 2 version,  input 220V and input 115/230V version.  When using input 115/230V version for 220V input, the 2 primary coils must be connected in series : Brown ,(Violet-Grey), Blue.  for 2 secondary coils , connect them in series as red , (black-yellow), orange , to become 15-0-0-15V.  As I remember, the DC resistance across each secondary coil is about 1.5 ohms."_
  
 But I do not see any difference, still it will be black-yellow as 0V for secondary.


----------



## Tribbs

Just follow the wiring diagram.



Mains to PRIMARY:
 Brown and Blue connect to your mains AC 220V (fused)
 Violet and Grey shorted together.

SECONDARY to Lovely Cube:
 Red to AC 15V (top screw connector)
 Orange to AC 15V (bottom screw connector)
 Black and Yellow shorted together and connected to 0V (middle screw connector)

Simple!

Now, wear your protective suit and plug it in... 
[joking]


----------



## Tribbs

mikaelmark said:


> I have now asked a friend at my work about this project, as he is an old men with good know how in electrical - and he said it should be fine to drive the LC with battery connected after the rectifier diod´s. It will also be fine if connect the battery before the diod´s, but preferrable after (to 15VDC in).
> 
> But the two big 4700uF (or in my case 10000uF) filter cap´s should be used.




Something I recently came across http://tangentsoft.net/elec/vgrounds.html


----------



## mikaelmark

tribbs said:


> Something I recently came across http://tangentsoft.net/elec/vgrounds.html


 
 Yes, tangentsoft is a useful site about some portable amp´s like Chu Moy and Pimeta and some OpAmp´s.
  
 Thank´s for the link - I´m gonna read that!
  
 Now, back to the "standard" LC with OPA627AU


  
 and 200VA 15-0-15VAC toroid: I just soldered the last few things and connect it to the wall outlet with 230VAC. On the secondary, there was 2x16,7VAC and all three led´s was litting and LM317/LM337 getting hot (as they should do).
  
 So in the evening today, I´m gonna connect a DAC to it and try with HD600 (I do´nt dare trying my HD800 at first attempt). Will report my impressions tomorrow.


----------



## mikaelmark

And here´s my impressions: First off, I connected my Squueezebox Touch to a china WM8740 DAC, then to the Lovely Cube with the HD600. Connected the AC wall outlet plugs and all LEDs litted up. Putted on the phones to my head; Was there something wrong? Could´nt hear anything. So I turned up the volume on the SB Touch and LC – Voila! There was music. I set the SB to pause, and now I could hear some background noise. -No, it was the wind outside the window blowing. Listening some more to the music, and all I can say is that the sound is really good!
  
 Then again I paused the music, and this time I again tought I could hear some noise. -No, now it was the neighbour vacuum cleaning!
	

	
	
		
		

		
			




  
 So my fear about using a lot of big caps seemed to be meaningless.
  
 After I unplugged the wall outlet plugs, I touched the LM317/337 heat sink´s, and could not hold them for any long time. But I assume it should be that way.
  
 Now I could not wait until I´m gonna test with my HD800 after some ”burn in”.


----------



## Tribbs

My LC is dead quiet at full volume and no input. If it wasn't for the LED light you would think it was turned off.


----------



## penmarker

Ditto here, my LC is completely silent and I can hear how some tracks has noise while others are completely silent - usually for low bitrate and/or vinyl rips.


----------



## Tribbs

I'm thinking about building a second one with all the trimmings. Already ordered a PCB and a few boutique components. I need to find a clone case compatible with the clone PCB.


----------



## penmarker

I'm on the verge of tears.
  
 I visited an unfamiliar subforum in my local forum to ask about my replica watch, and I had nothing but condescending replies, snide remarks, and snarky responses, and most of them made fun of how "_If you cannot afford to get a nice watch then take what you can get_".
 I'm no rich man, I have little money. It hit too close to home.
  
 And then I came here, and there's nothing but positivity.
  
 Thanks everyone, stay awesome. Though you people are strangers so far away, I feel welcomed as one of your own.
  
 Sorry for the off topic post, but my chest is too heavy.


----------



## sunneebear

Guess you have not met some of the Lehmann Linear fans when the Lovely Cube just came out.


----------



## Tribbs

mikaelmark said:


> Whoaa, now I´ve found something very interesting!!
> 
> DT9205A is an multimeter that can also measure capacitors by capacitance (2nf - 200uF/ not sure about up to 2000uF) and measure transistors by hFE.
> 
> ...




Mikael, do you use this DT9205A meter for hFE? Does it work for matching the transistor?


----------



## kkaky37t

I once had owned it.  顶。。。


----------



## mikaelmark

tribbs said:


> Mikael, do you use this DT9205A meter for hFE? Does it work for matching the transistor?


 
 Yes, the DT9205A works really well for measure and pairing the hFE values for the BC55/60C and BD139/40-16, so do also several of my small cheap DVM´s I´m having.
  
 The values differed quite a lot, especially for the BD139/40-16. Just be careful when measuring, as the hFE value will differ by temperature. It´s advise to using some (ESD) gloves or just wait for a while after touchind them before measuring - or just hold them equally long, it should be fine.
  
 But I´m disappionted about the capacitor measuring with the DT9205A, as it did not work. Have compared with Fluke 177, 187 and also more expensive Fluke´s, and they do fine. When I did a claim for the DT9205A to the eBay-seller, I then payed for a new unit, and when that one did´nt arrived, the seller shipped two more units after i claimed. But I did´nt get those either. So, the seller promised me to repay me, but I does´nt get any money. But eBay costumer service helped me get my money back for the second payment I did.
 Then I bought one more from another eBay-seller, but I was telled this unit was shipped back to the seller, and once again I get my money back.
  
 Also, the DT9205A is´nt really accurate when measuring for example resistance or voltages.


----------



## mikaelmark

kkaky37t said:


> I once had owned it.  顶。。。


 
 Did your DT9205A measuring capcitance for capacitors? (see my earlier post I just did)
  
 And why do´nt you have it now? Did it broke or have you sell it?


----------



## mikaelmark

penmarker said:


> I'm on the verge of tears.
> 
> I visited an unfamiliar subforum in my local forum to ask about my replica watch, and I had nothing but condescending replies, snide remarks, and snarky responses, and most of them made fun of how "_If you cannot afford to get a nice watch then take what you can get_".
> I'm no rich man, I have little money. It hit too close to home.
> ...


 
 Clones/copies are often much cheaper and use to be made in China or equal. And for the price, the manufactures use to save as much as the can in the components using for the item. And therefore, clones are usually not at the same grade as the original product - and so is this headphone amp. You the eBay clones for about $40 will not be comparable with the original for about $1200. And that´s what this forum is for, to helping and get each other tips and recommendation and it´s to everyone to decide how much to spend and acknowlede how the final product will end up. For me, I´ve spend about $300 for each of my LC, and now it´s of an higher grade than the original. And it´s more enjoying to assemble for yourself, and then have that in your mind when listening to it!
  
 So, you should feel very welcome to this forum - and why not build one for yourself? It must´nt cost so much to get a decent amp. for your headphones.


----------



## mikaelmark

Obviously not the most gorgously headphone amp. There are now aluminum plates for shielding between the parts, connected to the chassis. Also used a glue gun for isolating some wiring and solderings.
  
 Left to do now; assembling the black plastic volume knob with some epoxy glue and fix some soft feet underneath. Any suggestions?


----------



## mikaelmark

Maybe a wooded box on the outside should be nice.
  
 About the feet, the original LBC SE has SSC-feet. How important are those, ase the amp not having any movable parts, lika a CD-player? Maybe some soft rubber foam will be an alternative (as used for packing hard discs)? Already using some for my CD-player and home cinema amp.


----------



## Tribbs

Mikael,

Which power supply capacitors do you have in there?

I was also looking at those SSC feet. Same as the original Lehmann but so expensive for no benefit other than for beauty.
Beautiful girls are expensive but with more benefits 

I decided to purchase the UNI-T UT61A from Amazon for $36 shipped.
http://thebrightsideforums.com/viewtopic.php?f=15&t=1334
I could use an extra DMM.

It comes with a special plug for measuring transistors which ONLY works with model UT61*A*.
The higher level models, UT61B,C,D,... do not have the hFE transistor measuring function.


----------



## laughingbuddha

Dose anyone here have experience with Lehman Clone as a preamp ?

Is there anything that should be altered to improve upon ?


----------



## penmarker

laughingbuddha said:


> Dose anyone here have experience with Lehman Clone as a preamp ?
> 
> Is there anything that should be altered to improve upon ?


 
 For a while I used it to connect with my active speakers, the Hivi Swans A30. It worked really well since the speakers' volume control lags a lot. The preamp out allows you to adjust the line out volume.


----------



## Zulkr9

I was thinking of gettting this as my ss amp, can anyone comment on how it sounds compared to the Gustard H10 and other amps. im looking for a warm sound.


----------



## mikaelmark

Oh noo, what have I done?
	

	
	
		
		

		
		
	


	



  
 Just touched the heat sink for LM337 to with a metal tool to chassi, so it sparkle and banged. When I measured afterwards, the heat sink has +14,6VDC and not ground.
  
 But everything seems to work fine. May anything in the amp or the connected headphones (HD800) been damaged?
  
 And because the chassi is grill ventilated, the temp for the transistors, voltage regulators and the two big filter caps has140 Fahrenheit/60 Celsius and other parts 86Fahrenheit/30 Celsius. Is this too low? Should´nt the transistors be about 185 Fahrenheit/85 Celsius? Maybe I should make less ventilated?


----------



## mikaelmark

Maybe I´ts the wrong way to use ventilated chassi or separate the parts with aluminum shielding plates or use bigger heat sinks to lower the temperature!?
  
 Above is from LC homepage mod´s/findings:
  
My Advices :

Don't try to cool down the transistors by changing large heat sink or remove and mount on the case . No worries about burn out the transistor , the transistors' (BD139/140) max. junction temp is 150°C (http://www.datasheetcatalog.org/datasheet/fairchild/BD139.pdf)
Don't try to make holes on the case for ventilation. This doing will destroy the heat traps.
Use similar case. It is recommended not to use large case, large case cannot trap heat well.. If cannot find suitable case , buy from me  .


----------



## Tribbs

I have always wondered about the LC temperature argument. You can use the argument that the transistors performance is optimized at a high temperature. But, at what cost to other components, especially capacitors?

You will notice the latest version of the Matrix M-Stage (another Lehmann clone) has vents for cooling:


----------



## shaman11

thats really stupid. Semiconductors hate heat.you get odd distortions if you heat them up.
  
 why did kress and other companies put huge heatsinks (more than 50% of the case)
 inside their highend amps ???
  
  
 Transistors:
 pair them and you will be happy.
  
 I use this schematic to pair my transistors:
  
http://www.fantasyjackpalance.com/fjp/sound/synth/synthdata/16-minimoog/002/905-matching-transistor.gif
 it is from bob moog. A synth genius from the seventies.
  
 the bc550/560 are the parts who define the sound of this amp. different parts sounds different here.
  
  
 A good (!) 4 digits Fluke DVM is enough for pairing without the moog schematic. This cheap china crap like the one in this thread is not accurate enough for me.
  
 for power supply I use 2 lead seal batteries. Wonderful warm sound.
  
 At the moment I try a shunt regulator design for line supply. the lm3xx is real crap.
  
 cheers
  
 Shaman


----------



## Tribbs

You don't need accuracy to "match" transisters.

"_The 4 output transistors (BD139/140) have BEST performance at about temp 70°C_"
"_The 4 Capacitors (470uF) have BEST performance at about 50°C_"


----------



## mikaelmark

I have now burned in everhing, and made a deeper listening session. I used my HD600 with Cardas cable, a $350 RCA-cable connected to a modded AK4399 DAC.
  
 First I was listening to some songs from Spotify, and the impression was intermediate. When I then swapped to 16 bit 44,1 khz (CD-quality) everything was changed - the music was floating all around me and I could spot every note and instrument with high precision with a huge sound stage. Really impressing. When the LC was connected to a speaker amp, the sound were also nice, but just not as good as with the headphones. I have now to try my HD800 and also with higher quality songs, like 24 bit/ 192 khz.


----------



## mikaelmark

Will the amp work fine if I remove all the three LED´s?
  
 What´s the purpose for the two LED´s after the 4K7 resistor inside the chassi?
  
 I know the one after the 15K resistor is for the power, but the other two will not bee seen as the are inside the chassi. Should it be safe to remove all of them?


----------



## mikaelmark

When I have no DC coupling caps at the signal path input for LC and measure DC offset at headphone out, it seem´s there is almost 200 mV. But after a few seconds, it drop to about 0 mV.
  
 Is there anything to worry about, so I should maybe use coupling caps?


----------



## mikaelmark

Last weekend, I finalized my portable LC driven by 14 pcs AA 2000 mAh 1,2 V battery pack.
  
 It sounded quite nice, both when only connected to +/- 15V In to the PCB and with a TLE2426 virtual ground generator to GV.
  
 But the PCB will not generate any heat, every voltage regulator, transistor and capacitor will not be any warm at all (or very little).
  
 Should it be fine if the parts are cold? And is there any advantage of using the TLE2426?


----------



## mayday75

Hi guys,
 New to this forum(been reading it a little though), but not new to audio and DIY.
  
 I've had a BCL clone for a few years now. Don't now the name, the PCB says "JSDZ" and Ver: 100908
  
 I've tried, so far, NE5532, LM4562, OPA627.
  
 Finished a "discrete opamp" yesterday, did a bit of measuring today. 
  
 Parts are:
 4pcs 2SK170GR   3,4mA, 3,6mA, 3,4mA, 3,6mA
 2pcs 5R1 1206 SMD
 2pcs Bourns 10R multiturn variable resistor
  
 Fitted this on a DIP8-socket.
 When measuring with a pair of cheap in-ears as load and the inputs of the BCL clone hooked to an old cell phone, I got 0.0mVdc to +-0.8mVdc. Max time it's been powered on so far is about 20 minutes.
  
 That is as close to 0Vdc as I've gotten. I think my DMM might be off abit (or interfering) as when I leave the outputs alone for a while I get very close to 0Vdc(0VC +-0.1mVdc).
  
 I haven't removed the input caps yet, but could do it with zero issues as the USB-DAC I use as source has edcor signal transformers on the output instead of opamps, ie 0.000mVdc out from the DAC.
  
 When turning off the BCL clone, there's no pop or anything with the discrete "thingy", the music just fades away.
  
 What would be acceptable numbers in terms on mVdc on the outputs? I have not connected my Goldring DR150's to it yet as I want to know that it is safe first.


----------



## mayday75

Well, it's playing now...well I might add.
 Not nearly burned in yet, but still...
 Dead silent when there's a pause in the music, very dynamic and detailed. A bit muddy on some music (Pantera - Best of) but that may be lack of burn in time and/or more details to get used to.
  
 Also noticed a tendency to keep turning up the volume. That to me is usually a sign of clean sound.


----------



## mayday75

This is the opamps I have at home, have only used OPA627, NE5532, LM4562
http://i.imgur.com/7YydB0f.jpg
  
 Now I use the "discrete opamp" I made, but out of the opamps, which ones do you guys preffer?
 I might be building a BCL clone for my brother, or he might buy one of the completed clones. Still, would be nice to know what opamps might be good to use. He wants a little bit of a warm sound as his Shure headphones are a bit on the bright side according to him.
  
 My discrete opamp
http://i.imgur.com/SGxDUMm.jpg
http://i.imgur.com/7qGqWuQ.jpg
http://i.imgur.com/QdiKqwM.jpg
http://i.imgur.com/IjAya7x.jpg


----------



## mikaelmark

mayday75 said:


> Hi guys,
> New to this forum(been reading it a little though), but not new to audio and DIY.
> 
> I've had a BCL clone for a few years now. Don't now the name, the PCB says "JSDZ" and Ver: 100908
> ...


 
 For my portable BCL clone (LBC) with batteries connected to a FiiO X5, I measured about 10mV at 2/3 of full volume (normal listening level). Lowering the volume give less DC and with full volume I get about 40mV. All without DC coupling caps. I may try using some caps for the input, as it´s intended to have.
  
 Recommendation for DC at headphone out (with no music playing) is; Less than 20mV is fine, over 50mV give significant loss of audio quality and over 100mV can damage the headphones (or maybe the ear´s?).
  
 Just remember if not using any input coupling caps; if you change the source (DAC etc), it may give higher DC if that device not having some DC blocking for the output.


----------



## mikaelmark

Just finished up my portable (altough quite big and heavy) LBC powered by a battery pack a couple of weeks ago.
  
 The sound was quite ok, but I don´t think it was at the same level as the standard powered by a transformer. Maybe it had a bit more distorsion. And the voltage regulators and transistors did´nt get any (or very low) heat.
  
 So I connected a TLE2426 virtual ground generator paired with a 220uF electrolytic cap and a 1uF bipolar cap, connected to GV (between +15V and -15V at the PCB). But no difference.
  
 Maybe I should´nt have excluded the three LED´s, as they maybe have some importand function more than just lit!? So I´m gonna fit those LED´s and see what´s happening.


----------



## mayday75

mikaelmark said:


> For my portable BCL clone (LBC) with batteries connected to a FiiO X5, I measured about 10mV at 2/3 of full volume (normal listening level). Lowering the volume give less DC and with full volume I get about 40mV. All without DC coupling caps. I may try using some caps for the input, as it´s intended to have.
> 
> Recommendation for DC at headphone out (with no music playing) is; Less than 20mV is fine, over 50mV give significant loss of audio quality and over 100mV can damage the headphones (or maybe the ear´s?).
> 
> Just remember if not using any input coupling caps; if you change the source (DAC etc), it may give higher DC if that device not having some DC blocking for the output.


 
 I'll stick with the USB-DAC with the Edcor's on the output. Sounds great, very detailed.
 Never went above +-0,8mV regardless of volume, but one of the 2sk170's per channel acts like a CCS.
 I really like it so far, haven't gamed more than an hour or so (BF4) but the sound is improved there as well...atleast details etc, to early to say anything about soundstage.
 In my main stereo I have a TDA1541A DAC that took my quite a while to build as I tried to source the best part for each job, within reason.
  
 I haven't decided about the input caps, but as is right now, they perform no function whatsoever as the signal transformers does not put out any dc at all.
  
 Currently using Goldring Dr150's, they are ok but I wouldn't mind upgrading in the future. Had a pair of Philips SBC-1000, but one channel died unfortunatly and I couldn't find any problems with it.


----------



## mikaelmark

mayday75 said:


> I'll stick with the USB-DAC with the Edcor's on the output. Sounds great, very detailed.
> Never went above +-0,8mV regardless of volume, but one of the 2sk170's per channel acts like a CCS.
> I really like it so far, haven't gamed more than an hour or so (BF4) but the sound is improved there as well...atleast details etc, to early to say anything about soundstage.
> In my main stereo I have a TDA1541A DAC that took my quite a while to build as I tried to source the best part for each job, within reason.
> ...


 
 Altough a bit off topic, for my LC and AK4399 DAC, I´ve been choosen Elna SILMIC II, Mundorf MLytic, Panasonic FC, Holco resistors etc.
  
 In my DAC, I´m thinking about switching my 12 Mhz TCXO oscillator with 25 ppm to a Vanguard 0,1 ppm. Do you think it will do better for the sound?


----------



## mayday75

mikaelmark said:


> Altough a bit off topic, for my LC and AK4399 DAC, I´ve been choosen Elna SILMIC II, Mundorf MLytic, Panasonic FC, Holco resistors etc.
> 
> In my DAC, I´m thinking about switching my 12 Mhz TCXO oscillator with 25 ppm to a Vanguard 0,1 ppm. Do you think it will do better for the sound?


 
 Yes, the clock is an important part IMHO.
 I used a 0.1ppm Valab TCXO in my build, they just sell complete clock boards now I apparently.
 As far as the caps, it depends on where they are located in the circuit(excuse my spelling, just got out of bed and english is not my first language).
 Very important for sound, again IMHO, is a clean powersource. 78xx/79xx are evil  Actually looking at replacing the LM317/337 in my "LC" for something better. Haven't decided on if I should go with a plug n play(pin compatible with 317/337) replacement or separate boards.


----------



## nanchangbob

I replaced the 317/337 supply with MLytic's and quality parts to the Salas BIB Shunt regulated low voltage supply. They are a bit large and pricey to populate.
  
 A couple of other options are the Diyaudio stores super regulator or if you are comfortable with soldering SMD, the power supply boards sold with the Wire headphone amp uses 
 TPS7A3301 regulators that are nice low noise regulators and the boards are relatively small in addition one PCB provides both the pos and neg voltages.  
  
  
 I have been really happy with the sound of amp with this upgraded PS.


----------



## mayday75

> I replaced the 317/337 supply with MLytic's and quality parts to the Salas BIB Shunt regulated low voltage supply. They are a bit large and pricey to populate.
> 
> A couple of other options are the Diyaudio stores super regulator or if you are comfortable with soldering SMD, the power supply boards sold with the Wire headphone amp uses
> TPS7A3301 regulators that are nice low noise regulators and the boards are relatively small in addition one PCB provides both the pos and neg voltages.
> ...


 
 Haven't looked at caps yet.
 For Vregs I've looked at Jim's Audio super low noise shunt regulators and Kubota regulators so far.
 Also a pin compatible plug n play regs: TPS7A4700 15V 1A 4.17uVrms Ultra Low Noise/TPS7A3301 -15V 1A 16uVrms Ultra Low Noise.


----------



## mikaelmark

mikaelmark said:


> Just finished up my portable (altough quite big and heavy) LBC powered by a battery pack a couple of weeks ago.
> 
> The sound was quite ok, but I don´t think it was at the same level as the standard powered by a transformer. Maybe it had a bit more distorsion. And the voltage regulators and transistors did´nt get any (or very low) heat.
> 
> ...


 
 Yes, now when all the three LED´s are fitted, the sound is fine!
  
 Now I´m gonna fit everything in some aluminum case, but not too big and heavy, as it should be "portable".
  
 The only bad thing now is the DC current is a bit high without coupling cap´s -30 mV. So I´m gonna fit a pair of 2,2 uF Mundorf EVO aluminum with russian teflon FT-1 0,022 uF.
  
 Do anyone think 2,2 uF will be too high capacitance for DC coupling cap´s? Standard should be 1,5 - 1,8 uF. Some advice the bass will be able to go lower with higher capacitances. But are there any downsides?


----------



## Expansion

This project seems very interesting, but the information is not that well structured. I was thinking that I should try to  gather everything in a google docs spreadsheet: BOM, schematic variants, components types, etc.
  
 How did the schematic and the PCB leak?
 Is it 100% identical to the original?
 Has the PCB been modified to accept a dual mono power supply?
 Any other improvements?


----------



## francisdemarte

expansion said:


> This project seems very interesting, but the information is not that well structured. I was thinking that I should try to  gather everything in a google docs spreadsheet: BOM, schematic variants, components types, etc.
> 
> How did the schematic and the PCB leak?
> Is it 100% identical to the original?
> ...


 
  
 This would be a great idea! Unfortunately, I don't know if I can devote the time to this right now, I'm moving cross country and starting a new job. Most of the information is present in the thread, I've tried my best to link up all contribution to the first post.
  
 There are several versions of the board floating around. I assume they were all cloned from the original Lehmann Black Cube Linear. I've seen some with components moved around and in different places but the basic schematic is the same.


----------



## Tribbs

Here is a very nice 50VA 15V toroidal transformer available for the LC:

http://www.antekinc.com/as-0515-50va-15v-transformer/
http://www.antekinc.com/content/AS-0515.pdf


----------



## BucketInABucket

Anyone know the dimensions of the PCB of this board? Designing a custom enclosure around it will be fun


----------



## d4rkch1ld

How much output power this amp has?


----------



## mayday75

I have removed all PSU parts from the PCB for the BCL clone.
 I'm just waiting for a few parts to arrive to finish my dual rail LT1083 Vreg board(veroboard).
 I'll use this to power the headamp fed by a 2x15VAC 1A toroidal transformer.
  
 Should be an improvement over the 3XX onboard PSU.
 Hopfully it will also cure the problem of the two 1000uF/35V Pana FC caps closest to where the 3XX's used to be getting a bit hot.


----------



## jbaldam

Hi, I have just replaced the op amp with a mk 5 module from ss audio of australia.
 The sound is much improved but I find that different dip switch positions seem to alter the dynamics especially in the bass region, depth as well.
 should the dip switches act in this manner?


----------



## listen4joy

I bought this
 http://www.ebay.com/itm/Updated-version-E-01-Headphone-amplifier-Amp-Shielding-transformer-/111710544974?hash=item1a0277a44e:g:QikAAOSwHnFVl721
  
 this transformator will fit?
  
http://www.antekinc.com/as-0515-50va-15v-transformer/


----------



## mikaelmark

jbaldam said:


> Hi, I have just replaced the op amp with a mk 5 module from ss audio of australia.
> The sound is much improved but I find that different dip switch positions seem to alter the dynamics especially in the bass region, depth as well.
> should the dip switches act in this manner?


 

 I have only listened with all DIP´s off for 0 db, and when using my Squeezebox Touch at 24 bit 192 kHz FLAC files through a AK4399 DAC with an Supra Sword interconnect cable at $400, the sound is incredible and the sound stage is wide open and very detailed when listening with my HD650 with Cardas cable. But when I switch to my HD800 with standard cable, I must say I prefer the sound from HD650!
  
 May this be due to the DIP switch? Should the DIP be set to a higher gain with the HD800? If so, what is the preferred setting with HD800; 10, 18 or 20 db?


----------



## mikaelmark

mikaelmark said:


> I have only listened with all DIP´s off for 0 db, and when using my Squeezebox Touch at 24 bit 192 kHz FLAC files through a AK4399 DAC with an Supra Sword interconnect cable at $400, the sound is incredible and the sound stage is wide open and very detailed when listening with my HD650 with Cardas cable. But when I switch to my HD800 with standard cable, I must say I prefer the sound from HD650!
> 
> May this be due to the DIP switch? Should the DIP be set to a higher gain with the HD800? If so, what is the preferred setting with HD800; 10, 18 or 20 db?


 
 My LC having a couple of OPA627AD and with a step attenuator with the gain setting to 0 db, the volume knob is about mid 12 o´clock for normal listening.
  
 Most people seem´s to agree amp´s do their best with as low gain as possible, as long as the volume will be high enough for the headphones.
  
 So, maybe it´s only for my taste the HD650 do better then HD800!?


----------



## mikaelmark

Realized I´m getting some disturbing noise in the right ear, like from an old scratchy vinyl disc. So I did some research with hires FLAC´s 24/192, and here´s what I found:
  
 The irritating scratchy sound for the right ear is most noticed from songs like Norah Jones than Michael Jackson, more hearable with HD800 than HD600 (even if there´s a small hint of it with HD600) and undependent if using a thunder safe wall branchet or a standard branchet,
  
 Have cleaned all connectors with isoprophanol alcohol and then prepared them with Cardas Contact conditioner, except the phones 1/4 inch plug and the wall wart connectors. So I´m not convinced if there is a problem with the FLAC files, Squeezebox Touch player with Enhanced digital output app, the DAC (self assembled), Lovely Cube (also self assembled) or any of the cable/ connector!!?
  
 The research goes on... my next step will be to listen to the amp from another source, the source with another amp and maybe change interconnect Cable.
  
 Has anyone else experienced similar prolblem?


----------



## penmarker

I do notice Don't Know Why by Norah Jones have random popping and ticks. I think it's the mastering or mixing.


----------



## mayday75

Doing my "own" version of this.
 I can't call it mine as I've had help, I've taken bits and pieces of different schematics etc.
  
 So far I'm just in the LTspice simulating stage.
 It will be a fully discrete design, apart from the opamp in the DC-servo that is.
  
 I do have all the necessary parts for the build.
  
  
 Also;
 I'm looking for at new headphones.
 The ones in my pricerange are:
 Audio Technica ATH-AD700X
 Sennheiser HD598
 AKG K701 & K702
 Grado SR125i
 Beyer Dynamics DT880 250ohm and DT990edition 250ohm
 Philips Fidelio L2
  
 As you can tell they are all open designs, I prefer that sound.
 My Goldring DR150's has served me well, but I'm getting tired of glueing the plastic "headband" (no clue what it is called in english), that keeps cracking. It would also be nice having higher impedance headphones. I never use them with my phone etc anyway.


----------



## mikaelmark

penmarker said:


> I do notice Don't Know Why by Norah Jones have random popping and ticks. I think it's the mastering or mixing.


 

 Thank´s for your clarification, penmarker!
  
 So maybe it is down to the FLAC files nevertheless. One noteable thing is that also Linn´s 24 bit of Cristmas 24 bit 96/192 kHz appear to have same defect´s for the right channel.
  
 As I described earlier, I could not distinguish this defect for Michael Jackson. So maybe Michael J. album Bad is´nt so bad after all  I have heard that his recordings should be of high quality.
  
 And maybe the high-res files and the "high end" equipment reveal every defect.


----------



## mikaelmark

mayday75 said:


> Doing my "own" version of this.
> I can't call it mine as I've had help, I've taken bits and pieces of different schematics etc.
> 
> So far I'm just in the LTspice simulating stage.
> ...


 

 We are all "kids" in the beginning, so don´t feel shame that you have take help from person´s with more experience. I have also asked a celleague at my work with good know how in electronics. Also this forum is a nice help.
  
 When it comes to headphones, I´m a bit of a collector, so have some in my shelf and that I not use, such as: Sennheiser HD595, HD600 (optional with cable from HD650), AKG K702 modded with single ended UP-OCC Cable (sound is on the same level as my HD650 with Cardas Cable, just a bit different). Not quite shure I really want to sell the AKG.
 I also can think of selling my HD800, but of course the price will be in another category.
  
 Where do you live? I´m in Sweden, so if you´re in Europe it should be thinkable, I guess.


----------



## penmarker

Currently I'm using the HD650's predecessor, HD525. They all have the same characteristics and require some massive voltage swing. I reterminated the stock cable with a 4 pin XLR and tried out some powerful balanced amps. They sang so much better I couldn't believe my ears. They're different cans with voltage swing.

Can we increase the output power of the LBC?


----------



## mayday75

mikaelmark said:


> We are all "kids" in the beginning, so don´t feel shame that you have take help from person´s with more experience. I have also asked a celleague at my work with good know how in electronics. Also this forum is a nice help.
> 
> When it comes to headphones, I´m a bit of a collector, so have some in my shelf and that I not use, such as: Sennheiser HD595, HD600 (optional with cable from HD650), AKG K702 modded with single ended UP-OCC Cable (sound is on the same level as my HD650 with Cardas Cable, just a bit different). Not quite shure I really want to sell the AKG.
> I also can think of selling my HD800, but of course the price will be in another category.
> ...


 
 Hi, did you get the PM I sent you?


----------



## mayday75

mikaelmark said:


> We are all "kids" in the beginning, so don´t feel shame that you have take help from person´s with more experience. I have also asked a celleague at my work with good know how in electronics. Also this forum is a nice help.
> 
> When it comes to headphones, I´m a bit of a collector, so have some in my shelf and that I not use, such as: Sennheiser HD595, HD600 (optional with cable from HD650), AKG K702 modded with single ended UP-OCC Cable (sound is on the same level as my HD650 with Cardas Cable, just a bit different). Not quite shure I really want to sell the AKG.
> I also can think of selling my HD800, but of course the price will be in another category.
> ...


 
 Hey, check your inbox again


----------



## mayday75

Well, I've landed on one of the designs I was testing in Ltspice.
  
 Both the jfet input and the diamond buffer will operate in class A.
  
 The whole thing will be built on double sided, plated though, perf board.
  
 The FFT looks quite nice. It'll be interesting to find out if it'll sound as good as I think it can.
 It will also be interesting to compared it to the modifyed "JHL" class A headamp I'm almost done building.
  
 Time will tell


----------



## mikaelmark

mayday75 said:


> Hi, did you get the PM I sent you?


 
  


penmarker said:


> Currently I'm using the HD650's predecessor, HD525. They all have the same characteristics and require some massive voltage swing. I reterminated the stock cable with a 4 pin XLR and tried out some powerful balanced amps. They sang so much better I couldn't believe my ears. They're different cans with voltage swing.
> 
> Can we increase the output power of the LBC?


 

 For my LBC´s (including the portable battery version), I use four 1000uF (470uF is standard) Nichicon KZ Muse and two 10000uF/6800uF (4700uF is standard) Mundorf Mlytic in the power stage. I think this will maybe generate a bit better attack´s and be well suited for power hungry headphones.
  
 And don´t forget that higher the gain switches will not higher the power, just the volume (perhaps a bit more attack, but at the cost of worser sound).


----------



## mikaelmark

mikaelmark said:


> Thank´s for your clarification, penmarker!
> 
> So maybe it is down to the FLAC files nevertheless. One noteable thing is that also Linn´s 24 bit of Cristmas 24 bit 96/192 kHz appear to have same defect´s for the right channel.
> 
> ...


 

 I have now listen to some high-res files, and I must say there is a huge difference i quality. Many of them are bad sounding with noice/crackling sound while some are just magic, like Cassandra Wilson and some jazz music tend to be very nice sounding!


----------



## penmarker

mikaelmark said:


> For my LBC´s (including the portable battery version), I use four 1000uF (470uF is standard) Nichicon KZ Muse and two 10000uF/6800uF (4700uF is standard) Mundorf Mlytic in the power stage. I think this will maybe generate a bit better attack´s and be well suited for power hungry headphones.
> 
> And don´t forget that higher the gain switches will not higher the power, just the volume (perhaps a bit more attack, but at the cost of worser sound).



 
 Do you have a recent picture of your Lovely Cube?


----------



## mikaelmark

penmarker said:


> mikaelmark said:
> 
> 
> > For my LBC´s (including the portable battery version), I use four 1000uF (470uF is standard) Nichicon KZ Muse and two 10000uF/6800uF (4700uF is standard) Mundorf Mlytic in the power stage. I think this will maybe generate a bit better attack´s and be well suited for power hungry headphones.
> ...


 
 Those pictures are at my latest desktop model. Also, I have another one with THS4032 OpAmp, just need an enclosure.
  
 Then I also having a portable version with OPA627.


----------



## penmarker

I was hoping to see the insides because I'm interested in the components you upgraded/replaced.


----------



## mikaelmark

penmarker said:


> I was hoping to see the insides because I'm interested in the components you upgraded/replaced.


 
 Ok, I see!
  
 Below the link to my album with both my desktop and portable model, no password needed. The biggest different is the portable one "only" has Mundorf EVO bypassed with FT-1 teflon and two THS4032 with a 0,1uF cap for each, instead of OPA627 and no power supply section with rectifier diod´s and of course two battery pack´s instead of a toroid transformer. Otherwise most are similar, such as Dale 24 step volume attenuator.
  
 Just tell me i you´re interested in something, as I got new spare´s of most of the part´s.
  
 http://1drv.ms/1YPZli0


----------



## HumanSaurusRex

Hi guys! really need your help here as I can't decide on my own.
  
 which is currently the best assembled lehman clone board to get? 
  
  
 Thanks and best regards


----------



## mikaelmark

humansaurusrex said:


> Hi guys! really need your help here as I can't decide on my own.
> 
> which is currently the best assembled lehman clone board to get?
> 
> ...


 
 Mine, off course!  Jjust kidding 
	

	
	
		
		

		
			




  
 As far as I know, the unit from http://alicemagicbox.com/lasercollection/lovelycube.html is the best you can buy and you can choose if you prefer ot fully assembled and with or without enclosure and what OpAmp you prefer and he are also selling a step attenuator with SMD-resistors.
  
 Think it´s at least the same level as the original Lehmann BCL, but at a much lower price.
  
 Of course, Lehmann also has the BCL SE, that is at a bit higher level, but you have to pay much for it.


----------



## Amictus

humansaurusrex said:


> Hi guys! really need your help here as I can't decide on my own.
> 
> which is currently the best assembled lehman clone board to get?
> 
> ...


 
  


mikaelmark said:


> Mine, off course!  Jjust kidding
> 
> 
> 
> ...


 

 I agree with the above. I own the Lovely Cube "Premium" and also the Lehmann Linear SE. The story is that I was so impressed by the Lovely Cube that I arranged to compare it to the Lehmann Linear and the Linear SE. Both the Lehmann units were new. On the day, my much burned-in Lovely Cube sounded better than the Lehmann Linear, but the Linear SE was better by a margin than both the others. The bottom line is that Lovely Cube "Premium" from the link quoted by mikaelmark is a sure-fire bargain with lovely build quality. I upgraded the opamp at the dealer's suggestion. He was most helpful.


----------



## mikaelmark

amictus said:


> I agree with the above. I own the Lovely Cube "Premium" and also the Lehmann Linear SE. The story is that I was so impressed by the Lovely Cube that I arranged to compare it to the Lehmann Linear and the Linear SE. Both the Lehmann units were new. On the day, my much burned-in Lovely Cube sounded better than the Lehmann Linear, but the Linear SE was better by a margin than both the others. The bottom line is that Lovely Cube "Premium" from the link quoted by mikaelmark is a sure-fire bargain with lovely build quality. I upgraded the opamp at the dealer's suggestion. He was most helpful.


 
 Nice to hear!
  
 And yes, I bought two pairs of OPA627AU from Stephen_ alias Lasercollection_. I also thought he´s very helpful and answered my questions.
  
 What OpAmp did you get in your Lovely Black Cube Premium?
  
 Was there any other modification to the amp from the standard LBC Premium shown at his home page?


----------



## mikaelmark

penmarker said:


> I was hoping to see the insides because I'm interested in the components you upgraded/replaced.


 

 Could you see my pictures in the link? http://1drv.ms/1YPZli0
  
 If you´re interested, I can give the full parts list used in my LBC´s.


----------



## penmarker

Hi, Yes sorry, sorry, I did get the link and I can view it. You have so many different parts in it now it looks almost completely different


----------



## Cidious

I have been reading over this topic because I am in the market for one of these nice BCL clones. Since I am located in China right now my options are even more numerous. I have been searching on Taobao.com and found some really nice fully finished clones ranging from only $75 to $200 fully assembled. 2 models really got my attention and I ordered both to play around with and compare.
  
 Here are the puppies. (I know both links are in Chinese. Use google translate and look at the pictures. You will figure it out. I don't read Chinese and I order the **** out of Taobao every day! Big kid in a freaking HUGE ASS and CHEAP candy store! HEHE!)
  
 Jays Audio HPA-1 2015 ($180)
 http://s10.postimg.org/ayuycc0qh/TB2g_KUXf_XXXXXX4_XXXXXXXXXXXX_17455497.jpg
 https://item.taobao.com/item.htm?spm=a1z09.2.0.0.OOgc6H&id=41292352428&_u=r2esj2rk1eaa
  
 X-Melodious Lehmann headphone amp ($180)
 http://s10.postimg.org/qbjak3pa1/TB2_VPiaf_XXXXXb_ZXp_XXXXXXXXXX_647667811.jpg
 https://item.taobao.com/item.htm?spm=a230r.1.14.22.5Eve9z&id=25554524082&ns=1&abbucket=17#detail
  
 Both are build with genuine parts and I have had very direct contact with the owners who are dedicated and very serious but also friendly about their work. Both shops know what they are doing.
  
 Both designs are roughly the same but use their own designed PCB. the Jays Audio is on rev 4.0 now and the X-Melodius is on rev 4.0 too. Jays audio has been selling and upgrading their product since the beginning of 2014 and X-Melodius since 2013. Several revisions have been developed, produced and sold. Both are the 2015 versions. Both have a slight different approach to reach the best audio quality. The Jays Audio design stays as close to the reference Lehmann design as possible using the same components where possible to get the same sound signature as the original. The X-Melodius shop has a slight other approach. They replace some components with 'better' sounding components or components that have better availability. Both shops know what they are doing.
  
 I have spotted slight differences, The Jays audio uses higher grade polypropylene input caps (MKP) where the X-Melodious uses the inferior MTK series which are supposed to be not as good. The X-Melodious is carrying 2 Nichicon KG type 4700uf power caps which are really good caps vs the Vishay BC (supposed to be original) caps on the Jays Audio model. Also the Jays audio model is loaded with Vishay resistors where the X-Melodious uses Welwyns. The designer says these sound better. Also with the designing of the X-Melodious they chose to place the transistors on the bottem of the PCB probaby to cool them with the housing. I'm not totally sure about this. I will ask the designer. 
  
 Like I said I ordered both because the price is really low and I can sell the second one easily or give it away as a present. 
  
 I am just starting to look in the DIY audio world and I wanted these devices to tune them a bit more and learn more about DIY audio. If I break one of these puppies, my tears will be less than I would break a $700 device.
  
 I am using DT1770, DT770, DT880 and M50X headphones.


----------



## Cidious

Just got my 'Jays Audio' clone. Burning it in now but I can already hear that it is really good. The shop showed me a parts receipt from RS supply with all the genuine parts on it. The Jays Audio was made on request. I took them one and a half day to put it together, which very reasonable to me. They soldered it with silver solder 3%. The board itself seems of good quality and the soldering fine.
  
 After the burn in I will do a good listening session and start the tuning.
  
 For now I have the following upgrades planned. Parts are already in or coming in this week. 
  

Transformer upgrade from BLOCK (German brand) 40VA to BLOCK 60VA. This transformer just fits in the case and has a bit more grunt to feed everything.
Replacing input EPCON 1.5uf 250V with Mundorf MKP 2.2uf 250V caps like the SE model described a few pages back by vintageaxeman.
Replacing 470uf caps and I don't know with what yet. Some people upgrade them to higher capacity caps. Some people make a mix.. I have Panasonic FR 470uf 35V, Elna Silmic 470uf 25V (BIG) and Panasonic FC 470uf 35V caps lying around. I could make a mix. I was maybe thinking of putting the Elna Silmics with the Opamp and make the rest FR.. I have replace the caps in my Aune T1 with Elna and Panasonic FR caps and this worked out really well.  But I'm not totally sure about this yet.
I am also replacing the audio cables with the Mogami Neglex Quad cables like the SE model. I was looking at the SE clone on page 69 and I see that vintageaxeman used 4 piece of cable with each 4 cores to connect to the RCA connectors. Which means 2 seperate wire cores per solder point. I am not sure how this would work out.. I have biamped and bi-wired speakers before but not sure if this is a smart thing in the signal path that is not prepared for it. It would be great if someone could help me out with this question and explain if this would be good of bad to seperate 2 wire cores in between 2 solder points.
I have already replaced the opamp for a OPA2604AP dual model. But I am also interested in separating the channels per opamp. 
I was thinking about also replacing the power supply caps with the high-end Mundorf ones from the SE version but they are quite expensive and I am not sure if it is really needed since the Philips/Vishay BC's are supposed to be quite good. Maybe with the new transformator it could be useful but this is on the bottom of my list right now.
  
 Any tips and comments on my plans are more than welcome.
  
 Since I am a new member I can not post pictures yet but I have a huge amount ready.


----------



## mikaelmark

cidious said:


> Just got my 'Jays Audio' clone. Burning it in now but I can already hear that it is really good. The shop showed me a parts receipt from RS supply with all the genuine parts on it. The Jays Audio was made on request. I took them one and a half day to put it together, which very reasonable to me. They soldered it with silver solder 3%. The board itself seems of good quality and the soldering fine.
> 
> After the burn in I will do a good listening session and start the tuning.
> 
> ...


 
  


cidious said:


> Just got my 'Jays Audio' clone. Burning it in now but I can already hear that it is really good. The shop showed me a parts receipt from RS supply with all the genuine parts on it. The Jays Audio was made on request. I took them one and a half day to put it together, which very reasonable to me. They soldered it with silver solder 3%. The board itself seems of good quality and the soldering fine.
> 
> After the burn in I will do a good listening session and start the tuning.
> 
> ...


 
 I think that will be a good idea to use two Elna Silmic´s in signal path (nearest OpAmp), it´s just what I´m having on mine and I agree they´re big, especially if they´re 50V as mine.
  
 For the other four I´ve choosed Nichicon KZ Muse 1000uF 50V, but I thinkt those are not equally critical at for the two in the signal path. Just don´t mix cap´s for those two and the other four themselves.
  
 Wishing you good luck and nice listening time, and to all you Head-Fi -ers: Happy New Year 2016!


----------



## Cidious

Thnx for your response.
  
 In the mean time I have replaced all the 4 power supply capacitors with Panasonic FR 470uf 35V and the other two with the opamp for 2 Panasonic Pureism 470uf 25V capacitors. The Purism capacitors are supposed be good too and they are a little less wide and taller. So they just fit. If I don't like the sound after burn in, I'm going to try the Elna's anyway.
  
 I have replaced the input EPCOS 1.5uf MKP caps with Mundorf Mlytic MKP 2.2uf caps.
  
 I have replaced all the Wima FKP2 caps with ERO 1830 MKP caps, and the 2 little ones with the opamp for 2 polystyrene LCR caps. I also have some ERO 1830 MKP caps for this positions so if I don't like the LCR's i'm going to swap them too for ERO's.
  
 The 60VA Block transformer is on the way to replace the 40VA one.
  
 Replaced the cables with Mogami Neglex dual core cables shielded per RCA connector.
  
 When the 60VA transformer arrives I will give this girl a spin.


----------



## Cidious

The Next project will be a Beyerdynamic A1 clone. Because of the convenient 2 switchable inputs. I can do A/B comparison with different kind of DAC easily.


----------



## Cidious

I am still modifying the Jay's Audio Lehmann clone. I keep the X melodius the same for now so I can compare my improvements since they sounded really similar. 

What I did:


 Replaced transformer. Original 40VA BLOCK to 60VA BLOCK (just fits. Maximum size without any concessions or modifications to case) Also braided the cables for less interference like the original Lehmanns.
 Replaced input capacitors EPCOS MKP 654 1.5uf 250V with Mundorf MCap MKP 2.2uf 250V (Like Lehmann BCL SE version)
 Replaced all Wima FKP4 22nf 63V  caps for ERO MKP 1830 22nf 63V caps.
 Replaced 2 Wima FKP4 100pf 100v 630V caps with LCR 100pf 150V polystyrene caps. (als have some ERO MKP 1830 for these to try)
 Replaced 4 Nippon LZX 470uf 25V caps for Panasonic FR 470uf 35V caps
 Replaced 2 other (opamp) Nippon LZX 470uf 25V caps with Panasonic Pureism 470uf 25V caps
 Replaced cabling with Mogami Neglex 2549 cables. Soldered with silver solder onto motherboard
 Replaced opamp with dual discrete opamp OPA111VM with class A mod with 2 x 2.7K resistors. (Still working on a better adapter with less components and soldered.)



This is what it looks like now.



Replaced the 40VA (already bigger than 30VA original) BLOCK transformer with a 60VA BLOCK. BLOCK is a german quality brand. I had to import the BLOCK from Europe to China. I didn't want Chines junk)





Nice braid


Mundorf MCap MKP 2.2uf 250V (ugly ****ers but sound good) and ERO 1830 MKP 22nf caps



Panasonic Pureism 470uf 25V caps with the opamp. I also have Elna SILMIC II's but they are really big and I wanted something that fits nicely so I figured the Panasonic Pureism could be worth a try. Have not run with the Elna's yet so I can't give you a comparisson right now.



Left are the LCR polystyrene caps. Will do A/B comparison with ERO 1830 MKP caps.




Mogami Neglex 2549 (dual core instead of the quad core) cabling. Very well shielded cable. Soldered them to the board like its supposed to be.



Opamps (2x OPA111VM mono discrete) with Class A bias, 2x 2.7K resistors. Still testing.






Thats one sexy machine






Even love the blue light!




I am still making modifications. To do list:


 Shielded Schurter AC switch/fuse housing on the way right now.
 Creating new opamp adapter with less fragile connections.
 Compare LCR 100pf caps with ERO 1830 100pf caps
 Compare Panasonic Pureism 470uf caps with Elna SILMIC II caps

And I am still wondering if I should increase the capacity of the two big blue Vishay caps since I upped the capacity of the transformer by a substantial amount.. Maybe people here could give me some guidance about what to do. If I would replace the two blue Vishay's I would replace them with the Mundorf Mlytic 6800uf caps or 4700uf caps if the capacity is already sufficient. I also kept the 470uf caps at the same capacity. Maybe they need to be a bit larger now. I'm not sure.

Also I see that the TS has bypassed 'iput caps'. Not sure what he exactly means by that but if we take a look at the original Lehmann BCL SE, we can see that Lehmann removed the Wima FKP4 caps before the Mundorf MCaps. So maybe this could be an interesting mod to do too. I could bypass them with some good copper wire. Als the ones in between the Pureism caps are left out on the SE version. 







Tell me what you think and tip me if you have any tips for me to make this project even better.


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## Laybar

some pictures of my project, I am very satisfied with my work.


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## Cidious

That is a CLEAN looking project mate! Really nicely done! Can you tell us more about the chosen parts and the progress? I recognize quite some parts but a description would be nice!
  
 PRO BUILD! PROPS!


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## Laybar

Therefore, the resistance AUDIO NOTE, electrolytic capacitors MUNDORF, ELNA SILMIC II, polyester capacitors AMTRANS AMCH, WIMA RED, polypropylene capacitors OBBLIGATO GOLD, CLARITYCAP ESA, potentiometer NOBLE, PCBs made by me, TALEMA encapsulated toroidal transformer and EMI filter network SCHAFFNER.


----------



## Cidious

laybar said:


> Therefore, the resistance AUDIO NOTE, electrolytic capacitors MUNDORF, ELNA SILMIC II, polyester capacitors AMTRANS AMCH, WIMA RED, polypropylene capacitors OBBLIGATO GOLD, CLARITYCAP ESA, potentiometer NOBLE, PCBs made by me, TALEMA encapsulated toroidal transformer and EMI filter network SCHAFFNER.




Pretty exclusive component choice and and a respectable job on the pcb! 

What are the specs of the transformer if I may ask? It looks a bit small but I think your case and pcb are quite big. 

Why have you chosen to use ELNA Silmic II in the power circuit? Their specs are not the best available for the power section. Panasonic FC, FM OR FR would beat them there.. interesting choice though. Can you explain more about your component choices?


----------



## Laybar

the transformer and the model RS0030P1-2-015K 30VA 2 x 15V, accept tips to improve my amp.​


----------



## Cidious

laybar said:


> the transformer and the model RS0030P1-2-015K 30VA 2 x 15V, accept tips to improve my amp.​


 
 Ok here we go,
  
 I think your transformer can have an upgrade. In my opinion it's not sufficient enough to drive the Lehmann to its glory. I used a 40VA BLOCK which is a really high quality transformer from Germany and I upgraded it to a 60VA BLOCK now. I can tell you, you can hear the difference! I also used a 40VA Talema, the bigger brother of yours in between and I can tell you with confidence the 40VA BLOCK was the better one there too. Upgrading the transformer gives it more headroom. This resulted in more punch and a faster and fuller sound in my case. Probably it can do the same for you. Don't think to light of the power supply. This is most of your sound. It can make the difference between a dull and boring sound and a really lively and punchy sound. Bigger IS better in this case. It's the heart of your machine pumping the blood through its veins. 
  
 Also I think you can better change the 4 ELNA SILMIC II's for Panasonic FR or FM or even FC will probably be better for the power circuit. The ELNA's are VERY good caps for the signal circuit but I find them a bit slow and muffling in the power circuit. The Panasonic's give me a more open sound. I also just tried the ELNA SILMIC's in the signal path replacing my Panasonic Pureisms and I haven't decided yet which ones I like best. Need to do some more A/B-ing. 
  
 And one little thing that is maybe just my preference.. But I would not use that connector for the transformer on your pcb. This is not a really solid connectiong and clean power is almost the most important factor in the whole device. I myself used these:
  

 They are brass copper inside and tinned on the outside. You can solder the feet in the motherboard and the connection will be more solid. Lehmann uses the same system in the original model. I auditioned the difference between soldering the wires directly and using these and heard NO difference between the two methods.
  
 The rest of your build looks really solid bro! Very nice and clean. I am almost tempted to create my own PCB too and start from scratch with a custom case and selected components. But I am first trying to get the best out of my clone first also for knowledge which components are preferred. I have unlimited access to components here in China for dirt cheap prices.
  
 I still have a BLOCK 40VA lying around but I am located in China atm so probably that would no make much sense. You can order the BLOCK transformers from www.rs-components.com. I ordered my 60VA from there because on Taobao.com I could only find 40VA and 80VA which would be to big for my case.
  
 what capacities are you using for your caps?


----------



## Laybar

I always thought of Talema 50VA, and I'll try to change capacitors ELNA Silmic II with panasonic. (470uf 35V everyone​)


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## Cidious

Don't change the ELNA SILMIC's around the opamp. They are doing a fine job over their. I found out that using Panasonic's here in this spot makes the sound more flat and less musical. The ELNA's are warmer and more dynamic. But you could change the 4 ELNA's for Panasonic FR's (they are the newest series and highest rated ones) at the power supply. If not available my next choice would be Panasonic FM and then FC. The FC are most widely available and very cheap and still very decent capacitors.
  
 But what kind of capacity are you using for the Mundorfs and the other caps?


----------



## mikaelmark

cidious said:


> Don't change the ELNA SILMIC's around the opamp. They are doing a fine job over their. I found out that using Panasonic's here in this spot makes the sound more flat and less musical. The ELNA's are warmer and more dynamic. But you could change the 4 ELNA's for Panasonic FR's (they are the newest series and highest rated ones) at the power supply. If not available my next choice would be Panasonic FM and then FC. The FC are most widely available and very cheap and still very decent capacitors.
> 
> But what kind of capacity are you using for the Mundorfs and the other caps?


 
 Nice work you have done too, Cidious!
  
 As for the transformer connections, remember that soldering is always the best! Ok, just a bit trickier if then decided to swap it than using cable lugs to with push connection or terminal block connectors with screws (also remeber those connectors mostly use standard steel/iron for the path).
  
 Also, I see you did a good looking job with the Mogami wire between the RCA´s and PCB using heat shrink - but in my projects I use to solder the signal wire directly to the thread (see picture below) for better signal path as the small tap included and intended for soldering is magnetic and I suppose it´s made of gold plated steel while the RCA chassi use to be made of non magnetic gold plated copper (much better for signal path).
  
 As for the 4 caps in the power supply, do you think Nichocon KZ Muse is a good choise or are maybe those similar as Elna Silmic II as they also are intended for use in signal path? I have those 1000uF 50V KZ in my LC´s and have not tried to swap them with anything else. http://www.nichicon.co.jp/english/products/pdfs/e-kz.pdf


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## Cidious

mikaelmark said:


> Nice work you have done too, Cidious!
> 
> As for the transformer connections, remember that soldering is always the best! Ok, just a bit trickier if then decided to swap it than using cable lugs to with push connection or terminal block connectors with screws (also remeber those connectors mostly use standard steel/iron for the path).
> 
> ...


 
 I had seen your solution. Of course there are always better ways of doing something for one purpose, but sometimes it will hinder another purpose. I think your aim is for maximum performance and you want to make sure all parameters are in check that every percent is checked and not working against the end result which is the best audio possible. 
  
 As where I am more of a rationalist when it comes to audio. Yes I like to work in the margins too but I have to admit.. replacing the signal wires with Mogami wires was probably overkill anyway haha. But I like to keep my builds clean and PRO. I wanted to use the SILMIC II's for the opamp position but they are SO big that I wanted another solution where the caps could still stand where they belonged and I made an concession and replaced them with the Pureism's which sound nice too btw.
  
 You builds look really techy. And I am VERY curious to give them a run. But if I would build like you I would loose control of my project haha and if I'd have any problem anywhere I would get lost in troubleshooting because I get lost with all the stray components  Don't get me wrong I really like you way of building. It's daring and ingenious!
  
 Talking about the caps. I think the Muses are very good caps too. I just know that for power supply implementations the Panasonics are hard to beat when you look at their specs and price. Very low ESR and high ripple current. Beating most other caps. I first used them in my Aune T1 after trying a couple of other caps and also ELNA for audio and liked the Panasonics the best. They sound open, detailed and very fast. When I used them in the signal path things got bad. They flattened out the sound and made it cold. This is where I find the ELNA SILMIC IIs to be REALLY pleasing. They create dynamics, warmt and musicallity. Tried the same ELNA's in the power path and my sound got sloppy and slow somehow. 
  
  
 Apart from this I am looking for my next upgrade and I am stuck on if I should upgrade the Vishay BC's for Mundorf Mlytic caps or not. They cost about $50 per pair.. that's not a cheap upgrade.. The Vishay BC's are already quite good. 
  
 I am also looking into removing the small input bypass caps like in the BCL SE. But I am not sure if this is a smart idea and how to implement this upgrade properly with bypassing with a wire or not.


----------



## mikaelmark

cidious said:


> I had seen your solution. Of course there are always better ways of doing something for one purpose, but sometimes it will hinder another purpose. I think your aim is for maximum performance and you want to make sure all parameters are in check that every percent is checked and not working against the end result which is the best audio possible.
> 
> As where I am more of a rationalist when it comes to audio. Yes I like to work in the margins too but I have to admit.. replacing the signal wires with Mogami wires was probably overkill anyway haha. But I like to keep my builds clean and PRO. I wanted to use the SILMIC II's for the opamp position but they are SO big that I wanted another solution where the caps could still stand where they belonged and I made an concession and replaced them with the Pureism's which sound nice too btw.
> 
> ...


 
 Thank´s for your impressions!
  
 So, maybe I´m gonna replace my KZ Muse in my amp´s. I see the favor ones the Panasonic FC, FM and FR (with lower ESR).
  
 Any suggestion about who of this will be best?


----------



## Cidious

From Panasonic the FRs is their latest top-end line with the best specs. Not all sizes are available but 470uf 35V is well available. The Panasonic FMs come next. Still very good specs but not as good as the FRs for the power path (read practically the same but marginally lesser specs). Slightly higher ESR and slightly lower ripple current. Not a big difference though! And then comes the FC line. Solid capacitors and VERY cheap and available in all types and capacities. Lowest specs of the 3 but still better than most other brands for the power supply in terms of ESR and ripple current. And the best thing about the Panasonic caps is that they are all small. Easy to fit in mostly any circuit. 
  
 https://industrial.panasonic.com/cdbs/www-data/pdf/ABA0000/ABA0000C65.pdf (Panasonic FR)
 https://industrial.panasonic.com/cdbs/www-data/pdf/ABA0000/ABA0000C63.pdf (Panasonic FM)
 https://industrial.panasonic.com/cdbs/www-data/pdf/ABA0000/ABA0000C59.pdf (Panasonic FC)
  
 http://www.nichicon.co.jp/english/products/pdfs/e-ukz.pdf (Nichicon KZ Muse)
  
 http://www.elna.co.jp/en/capacitor/alumi/catalog/pdf/rfs_e.pdf (Elna SILMIC II)
  
  
 It is a funny thing that Nichicon doens't give performance specs for its KZ line.. May indicate that there is something lacking..
  
 Of course numbers don't say it all, but it's a good indicator.
  
 Oh and BTW what voltage marking do your KZ's have? I found that the higher the voltage specs the higher the performance numbers are with the Panasonic caps at least. The 35V model has better specs than the 25V model. The same with the Mundorf Mlytics, the 63V version has considerably better specs than the 40v version of the 4700uf caps for example.


----------



## mikaelmark

cidious said:


> From Panasonic the FRs is their latest top-end line with the best specs. Not all sizes are available but 470uf 35V is well available. The Panasonic FMs come next. Still very good specs but not as good as the FRs for the power path (read practically the same but marginally lesser specs). Slightly higher ESR and slightly lower ripple current. Not a big difference though! And then comes the FC line. Solid capacitors and VERY cheap and available in all types and capacities. Lowest specs of the 3 but still better than most other brands for the power supply in terms of ESR and ripple current. And the best thing about the Panasonic caps is that they are all small. Easy to fit in mostly any circuit.
> 
> https://industrial.panasonic.com/cdbs/www-data/pdf/ABA0000/ABA0000C65.pdf (Panasonic FR)
> https://industrial.panasonic.com/cdbs/www-data/pdf/ABA0000/ABA0000C63.pdf (Panasonic FM)
> ...


 
 Ok, I see - thank´s!
 Have seen some people prefer the KZ Muse to Panasonic Fx in the power supply and some prefer Panasonic as at least the Silmic II will be too slow and muddy sound.
 For my four KZ Muse they are rated at 1000uF 50V.
 The bad thing with large Voltage rating are off course they´re bigger and may generate more noise in the application.
 So I´m gonna replace them with 25V Panasonic FR: http://www.ebay.com/itm/311517865756?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT


----------



## Cidious

Can you maybe explain to me why you chose to use 1000uf caps instead of the standard 470uf capacity? I kept them at the same 470uf size but just at 35V. I am wondering if I should enlarge capacity or not? I think the 4700uf caps are big enough but I am also still wondering if I should swap them out for the premium Mlytics.. They are quite expensive though at like 3 times the price of the Vishays while they are already considered to be quite good and definitely better than most Nichicons and Elna's for this function.. Will the Mundorf investment of at least $50 be worth the upgrade?
  
 Can you maybe comment on this and help me think on what I should do?


----------



## mikaelmark

cidious said:


> Can you maybe explain to me why you chose to use 1000uf caps instead of the standard 470uf capacity? I kept them at the same 470uf size but just at 35V. I am wondering if I should enlarge capacity or not? I think the 4700uf caps are big enough but I am also still wondering if I should swap them out for the premium Mlytics.. They are quite expensive though at like 3 times the price of the Vishays while they are already considered to be quite good and definitely better than most Nichicons and Elna's for this function.. Will the Mundorf investment of at least $50 be worth the upgrade?
> 
> Can you maybe comment on this and help me think on what I should do?


 
 The reason I choosed those four at 1000uF is that I have seen some done it. Also, I the two big ones ony my boards are 10000uF MLytic. Someone told higher this will get more power/"umph"/bass to the sound, but the downside may be worser PRAT (this means the music will not flow so homogenous - Phase, Rhytm And Timing).
 But that is what many people also tells about the Sennheiser HD800: it may not be equally musical as HD700 and lower series.
  
 Also, bigger parts may generate more noise, but I think this is more true for the two 470uF electrolytics in the signal path.
  
 Then, off course, higher capacitance will get bigger and more expancier parts.
  
 I have not experienced any noticeable problem, neither at my battery driven amp with the same kind of parts.
  
 I have just received my 1000uF 50V Panasonic FR from Germany - they´re so small and bland/insipid looking compared to my KZ´s. Gonna solder them in my LC the upcoming week(´s).


----------



## Cidious

I have decided to populate a new board.
  
  
  

 Got myself some PCB's. Chose the right one because of thicker nickel plated holes. The gold one is the same I used before. only good of 1 maybe 2 time soldering, then the plating comes off. Also I liked the positioning of the input bypass caps better. This way I can get better caps for this position. Mostly the same except for the 2 3R 2W resistors in between the big power caps.
  
 The board even says Lehman 
	

	
	
		
		

		
			





. That is just bad behavior! But ah well, I like it. Also got a new case with it because my old case saying 'Jay's audio' was made for the wider holes of the left PCB. Don't worry the new case only costs $20 and also says Lehmannaudio even with the BCL logo on it! 
	

	
	
		
		

		
		
	


	




.. Well this is China!
  

 Gathering some parts.
  

 Started soldering some basic components.
 Mundorf MCap MKP 2.2uf caps
 Wima MKP10 0.1uf caps
 Vishay Dale ERC55/RNC55 metal film resistors
 Vishay MSR125 metal film resistors
 Yageo 2W 1% resistors
 Amtrans AMCH 100pf caps
 ETC
  

  
 Expanded my opamp collection.
  
 2x mono discrete OPA111AM
 2x mono discrete OPA111VM
 2x mono discrete OPA627BP
 1x dual AD8620AR
 1x dual OPA2604AP
  
 Still waiting for more parts to come and I am still deciding on a lot of parts so I soldered in a lot of sockets so I can swap components quickly without soldering every time and risking to destroy the board.
  
 Will update my findings of parts selecting here.


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## Cidious

Soldered myself some sockets in for a hassle free A/B comparison of different capacitors.
 Will roll most of these capacitors:
  

  

  
 Prices are in chinese RMB (Yuan). So it's not very expensive here. But it's always the question if the parts are real or not. So lets just trust my ears and try all of them hehe.
  
 Even got some bipolar caps with em.. not sure what I will do with them yet..


----------



## francisdemarte

cidious said:


> I have decided to populate a new board.
> 
> 
> 
> ...


 
  
 Which vendor did you get the nickel plated board from? It looks to be of very nice quality.
 Thanks for sharing your builds!


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## Cidious

I got the board from a Chinese Taobao shop. The owner is quite rude but he sells unique high quality products. If people would be interested in could buy some for sending abroad since he doesn't ship internationally. I can also get the cases with lehmann logos in good quality very cheap. I am not looking for heaps of profit. Just hope that people people start building and sharing again in this topic.


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## Danielsc

Hello Cidious..

 I can be interested in these.
 Can you tell the prices of those items, and maybe also say what you should ask to ship it to Belgium?

 Thanks and regards.
 Daniel


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## Cidious

I am from the Netherlands but I am currently working and living in China. I will look what airmail will cost. since it's a really flat thing. I think you should order 2 at least for safety if something happens. I could put them in an bubble envolope with cardboard folder around them. (My family from the Netherlands is also coming over at the end of Februari. This could also be an option.)
  
 I don't know what shipping will cost but I will find that out for you.
  
 The boards itself costs me about 60 yuan including national shipping cost . That's about 10 euro to play it safe. Not very expensive. But the international shipping will be the main cost. 
  
 Maybe You could also order a case (original Lehmann design including logo's. I could mount the bare PCB in it and I could send the whole thing your way. I don't think they will be very difficult about import costs or counterfeit if its an empty case and board. A case will cost about 25 euro. 
  
 You can then fill it up with European parts from RS Components for example. They have some nice transformers that I also used. 
  
  
 I will look into the shipping costs from here to Europe.


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## Cidious

It's starting to look like something again. 
  
 Still waiting for some parts to come in:

Mundorf Mlytic 4700uf 40V caps
RA resistors for the out put positions. (Will test them against Vishay MBE0414 metal film resistors that originally belong in BCL.)
Some more ITT diodes. Ordered 4 of them but couldn't find to identical pieces to match.
  
 That's about it. I've got a nice collection of electrolytes ready to test in the PSU output and also a couple of high quality electrolytes 'for Audio' (85C) to test in the signal path. Next to that I have a lot smaller bypass caps to test near the opamp and with the input caps. I hope to find the sound I'm looking for. I have two DACs to test with. The Sanskrit 6 and an Aune T1 with different tubes. Everything is upgraded and maxed out. 
  
 Headphones will be: 
 Mr Speakers Mad Dog
 Beyerdynamic DT770
 Audio Technica ATH-M50X
 And possibly on short notice a set of Beyerdynamic DT1770
  
  
 Any questions about my reasoning to choose a particular type of part? Just ask! Advise is welcome too!


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## Laybar

I thought I'd use the Mundorf Mlytic 4700uF 63V.


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## Cidious

laybar said:


> I thought I'd use the Mundorf Mlytic 4700uF 63V.


 
 I tried! They are to high for the case by about 3mm.. I thought of lowering the mounting points of the PCB but then I would risk the soldering points contacting the case.. They just didn't fit. The original Lehmann BCL SE uses 40V too. Even though the 63V has a bit better specs than the 40V version. I think the 40V will do just fine. It's a low power device. The specs of the 40V mundorf are already a bit better than those of the Vishay BC caps that I already find really good and better than Nichicon. 
  
 I rest my case.


----------



## Cidious

I've finished the base build! I use most original Lehmann parts and from there on I will test different parts and combinations in the sockets I've installed. I also still got some RA resistors incoming for the signal outputs.
  

  
 First smoke test went fine. Turned it on with the standard OPA2134AP. good DC offset and parts didn't get hot.
 Then I dropped in my dual discrete OPA111VMs. DC offset = PERFECT! 
  

  

  
 Tried all other opamps and got no big excesses in DC offset. 
 Next step is to give the device some burn in time. Then solder the signal cables in and do some testing with some inexpensive IEMs and rechecking DC offset after a while. 
 Then the fun can begin! The parts testing. I've got a good collection of caps to test for the device. 
  
 PSU output: 
 Nippon LXZ 470uf 25V (standard, they seem legit)
 Nippon LXZ 470uf 35V (different colors and different batches)
 Nippon LXZ 560uf 35V (same series as the 470uf 25V)
 Nippon KZM 470uf 35V (same specs as Panasonic FR)
 Panasonic FC 470uf 25V (good old trusted FC)
 Panasonic FM 470uf 35V (near same specs as Nippon LXZ)
 Panasonic FR 470uf 35V (some like em some don't, i've had good experiences with them)

 For opamp:
 Elna Silmic II 470uf 25V (black/gold)
 Elna Silmic II 100uf 35V (black/gold)
 Panasonic Pureism 470uf 25V (audio grade)
 Panasonic Pureism 220uf 25V (audio grade)
 Nippon ASF 470uf 50V (audio grade capacitor used in high-end brands)
 Nippon ASF 470uf 25V (audio grade capacitor used in high-end brands)
 Nippon AWJ 220uf  25V (REALLY big for their capacity and power rating. Like Silmic. Considered High-end audio capacitor by Nippon. From their catalog the best I could find.)
  
 For the input bypass and opamp coupling positions:
 Wima FKP4 0.022uf MKP
 Shin Shin 0.027uf 50V Polystyrene
 Shin Shin 0.033uf 50V Polystyrene
 NIS 0.1uF 100nK 125vac MKP
 NIS  0.022uF (22nJ) 250v MKP
 AV R84 0.1uF 100v MKP
 SOSHIN LCR825 0.1uf(100n) 63v MKP
 ECQ-P 0.027uF (273J) 50v MKP
 ECQ-P 0.1uF (104J) 100v MKP
  
 Will be interesting to see how these influence the sound. I will change them at after all other capacitors.
  
 And after that I will have some RA 1W resistors to swap the Vishay MBEM0414s out. To see if this improves anything.


----------



## Cidious

End result:
  

  
 After some testing swapping and resoldering I have found a very sweet sounding and also looking combination of parts. 
  
 The PSU caps all sounded a bit similar but the LXZs did very well in general. That's why I settled for the 470uf 25V in the first place. I did have to put the gain on maximum to give my headphones the proper breathing space with the Sanskrit 6 DAC. After a while I found out that the 470uf 25V had to work really hard and got really hot. So I swapped them for the 560uf 35V caps which rounded the sound a bit. They are a tad less transparent, but in return I get a really smooth and powerfull sound versus the 470uf caps. Also I could turn the gain down after this mod together with switching the input bypass caps to the orignal Wima FKP4 again (You will read later about them)
  
 I tried different caps at the opamp but eventuall settled for the Elna Silmic II 100uf 25V. The Panasonic Pureisms where more detaild but also more harsh and this was something I want to evade at all cost because it tires me and hurts my ears. The Pureisms also tend to degrade a bit after burn in, while the Silmics get better and more detailed. 
  
 In between the Silmics I tried all caps I had ranging from 0.022uf to 0.1uf. I found the AV100 0.1uf caps sounding best and the Wima FKP4 0.022uf second best! Disregarding what was mentioned by bla bla in this topic that they would be notoriously bad for audio. I compared them A/B against audio grade mkp capacitors of the same size and bigger and except for the AV100 none of them were as clear and open as the Wima FKP4. The only negative effect of them I could notice was that they flattened out the sound just a bit more than the AV100. Well I installed the AV100 but I did it wrong.. bend the leads to close to the housing to make them fit nicely.. after 1 hour running the Elna Silmic next to it was on the edge of bursting and burning hot. Oops! Seems like the Elna didn't like doing all the work alone. Swapped the Elna's and the AV out and put the Wima FKP4 back.
  
 Decided to go crazy and just solder in the (very nice looking) Nippon ASF 470uf 50V caps. A bit overkill. I couldn't properly test them before because the leads were thicker than the mounting sockets. Just did a wild guess and followed my designer eye a bit because They really are sexy lookin'! And well, this worked out very well! The sound is a bit warmer than the Elna's which I personally like because it just took out a bit of the last harshness that was still in the tracks on the high end. Everything became smooth and in harmony. I am burning them in now for at least 100 hours to see what they will do without changing anything else.
  
 I tried the Shin Shin polystyrene caps as a bypass for the input caps. They worked quite nice but they also didn't work properly.. I had an channel imbalance in volume.. Popped them out. Tried several other caps but the Wima FKP4 were on par with the better caps I had.. So I said.. What.. I will go again with a design choice and keep the device nice looking and pop them back in. The sound opened up again on the right channel. Also tried ERO 1830 for this position.. they were a bit more neutral but less transparent. Another point for the Wima FKP4 caps. 
  
 I respect Bla Bla for all his input here which I also gratefully made use of. But on this particular thing of the Wima FKP caps he is just not right. There is no reason to avoid Wima FKP4 caps at all for audio circuitry. Lehmann chose them well.
  
 Did a REALLY proper cleaning after everything. With a somewhat rough brush and some (Chinese chemical) PCB cleaner. Then with a cotton swap and the same chemical poison that eats the skin of my hands and the printed letters of Wima caps. Then with a toothpick with the PCB cleaner and finally a cotton swab again to remove the loose bits of paste after the tooth picking. Guess what.. DC Offset lowered even more.. Only the OPA111AM has a low offset now. the rest is practically DC offset free. OPA111AM went from -1mv/6mv to 0mv/2mv. Really good!
  
  
  
 And that's where we are now. 5 hours burn in time.. REALLY enjoying my amp! Strong, natural, warm, dynamic, deep, wide etc. 
  
 I've tested the amp with several albums which are well recorded and have wide dynamic range:

 Nirvana - MTV Unplugged in New York (very nice for soundstaging, imaging and details. Very natural representation)
 Muse - Absolution (very dynamic album and really fun to listen to)
 R.E.M. - Automatic for the People (Really great vocals and intrument placing)
 Dr Dre - 2001 (clean male vocals and tight beats. cleanest hiphop album I know)
 Plastikman - EX (Guggenheim) (VERY LOW BASS! If you want to find out if your gear goes low enough.. if there is enough power available.. This will pull it out)
 Katie Melua - Piece by Piece (Very nice female vocals and nice dynamics in the instruments with great imaging)
  
  
 My next step will be building a matching DAC with the ESS Sabre ES9018 32-bit chip and a good power supply:
https://item.taobao.com/item.htm?spm...id=25873632122
  
 I made a deal with the shop to just buy most of the parts for a big discount (Y1800, thats about $275). I will replace some parts myself (reserve a budget of $50-75 for that) but in general the design and the parts choice looks already really good to me. And the case design will exactly fit the Lehmann. They are exactly the same length.


----------



## Cidious

Replaced out put resistors with RA resistors.. I know.. it all looks sexy now.. That's about everything that changed. The MBEM0414 resistors did a fine job before them. No noticeable difference.. But boy,  this is one sexy machine. Only looking for some black heatsinks for my opamps and I'm done.


----------



## mikaelmark

cidious said:


> Replaced out put resistors with RA resistors.. I know.. it all looks sexy now.. That's about everything that changed. The MBEM0414 resistors did a fine job before them. No noticeable difference.. But boy,  this is one sexy machine. Only looking for some black heatsinks for my opamps and I'm done.


 
 Interesting reading!
  
 What did you found was the difference between your Nippon LXZ 470uF caps vs Panasonic FR 470uF - what was the bad things  with  the FR´s?
  
 And why did you choose the Elna Silmic II at only 100uF and not 470iuF? Was there any change in sound?
  
 Also; What was the different between the OPA111 and OPA627? Why did you stay with OPA111?


----------



## Cidious

mikaelmark said:


> Interesting reading!
> 
> What did you found was the difference between your Nippon LXZ 470uF caps vs Panasonic FR 470uF - what was the bad things  with  the FR´s?
> 
> ...


 
  
 Most of it you can find in this dedicated thread how I started it. http://www.diyaudio.com/forums/headphone-systems/285380-headamp-upgrading-lehmann-bcl-clone.html
  
 I found the FR caps to be a little wider than LXZs but also a bit thinner. And at the time I was battling a harsh sibilance problem. That's why I've chosen the LXZs. But They got quite hot. I changed them for the 560uf 35V versions of the LXZs this made the sound softer, more round and with more 'oomph'. Analytic freaks should stay with the 470uf caps. I found the FMs to be nearly identical to the LXZs. Also the KMZ to be nearly identical to the FRs. This is not strange since they all have similar specs and size. What is the best cap depends on the rest of the parts and your preference. I tried to create a balance between components. 
  
 I chose the 100uf because of size and because I was told 100uf was enough for this position. One guy even told me if I didn't like harsh treble I could even go as low as 47uf. Which I also tried in the form of 47uf 25V Elna Silmics IIs. I found him to be wrong. I found that bigger caps soften sound, not smaller caps. But this should be calculable for the frequencies. But for now I can only share my experience. 
  
 The difference between the OPA627 and OPA111 is easy to describe. The OPA111 is more musical. The OPA627 is more analytical and a bit fast but less depth. The OPA111 is a bit warmer at the cost of some but not much detail.
  
 There is also difference between letter combination at the end of the type number. The OPA111VMs are much clearer and exact as OPA111AMs. AMs are warmer and more comfortable to listen too with bright headphones but with dark headphones like the Mad Dogs I prefer the VMs or the OPA627BPs. There is not one good opamp! I have found similar opamps to be sounding good with different DACs and music. But also changing components in the device made me want to roll between opamps. 
  
 Eventually I settled for the OPA111VM with a more smooth component selection.
  
 I think the Nippon ASF 470uf 50V caps that are in now are a bit to warm and buttery for me after burn in. But I will keep them there for a while until I build my new DAC. Then I will also try 220uf 25V Nippon AWJ (highest grade Nippon capacitor for Audio, just as big as the Silmic II series). To give you an idea of its size. The AWJ 220uf 25V caps are just as BIG as the ASF 470uf 50V caps.. So I will give them a try after I've build a new DAC to go with it if the sound is still to buttery for me. If they don't work out I will try some 220uf Elna Silmic II caps. The Panasonic Pureisms were the most detailed but sounded to harsh for me. Didn't give them the time to run in. But the 470uf Pureisms I had before that didn't seem to get better after burn in. So I have lost my trust a bit in them.


----------



## mikaelmark

I have now replaced the four KZ Muse with Panasonic EEUFR, and I must say I´m really pleased with them! Also replaced all Silmic !! cap´s in the Power supply  in my AK4399 DAC.
  
 The sound is so engaging and warm but still very detailed.
  
 But why is higher ripple better for cap´s in the Power stage? A friend at work told me ripple is usually not good and unwanted!?


----------



## Cidious

nice improvements. 
  
 I'm not totally sure about what specs are really good for PSU caps anymore. 
  
 I've tested a lot of caps and eventually settled for LXZs which almost have the same specs as the Panasonic FM caps. Which by specs would be inferior to the FR and Nippon KMZ caps..
  
 The thing is. When you look at the FM and LXZ caps they look even in design more expensive and are bigger then their brothers in the FR and KMZ series. I'm not totally sure which one to use in what kind of application. I am using panasonic FR 3300uf caps in my Aune T1 DAC and the are definitely better than the standard caps but It's also because the FR caps are smaller than the FM that I haven't tried the FM's or LXZ for these positions.
  
 Well I will be building my ES9018 DAC this week and will start doing some test again.


----------



## jenyst

*Cidious, *good afternoon. Could you please give a link where purchased separately case? Board as you have acquired on aliexspress, and the case can not find anywhere(


----------



## DoctaCosmos

Is this amplifier the same as the normal linear? A zero feedback amp?


----------



## Cidious

jenyst said:


> *Cidious, *good afternoon. Could you please give a link where purchased separately case? Board as you have acquired on aliexspress, and the case can not find anywhere(


 
 I have not aquired this board on Aliexpress but on Taobao.com. I am working and living in China. I am not familiar with Aliexpress. The taobao link is as follows:
  
 https://item.taobao.com/item.htm?spm=a1z09.2.0.0.57LJJf&id=170113399&_u=i2esj2rk165a
  
 The owner is a bit of a jerk but you can try to make him ship it internationally.


----------



## francisdemarte

Thanks for the link Cidious!  That page has some good information about changes to six capacitors in the 2013 revision of the board.


----------



## Cidious

It does! 
  
 Like I said. This seller aint friendly or helping but he knows what he is doing and he sells good stuff. Though he is using cheaper parts here and there. Like ST regs and stuff. But I am VERY happy with his board. Resoldered quite some parts already and the board doesn't bend or break a bit. 
  
  
 Btw I've replaced the The Wima FKP2 22nf caps with Wima Black Box caps of the same value on the opamp and input position. This made a slight improvement. The sound is just a tad cleaner.
  
 After that I've tried some different electrolytes for the opamp positions. had the big Nippon 470uf 50V caps there. They were very forgiving and buttery but also muddified the sound. I decided to give the Nippon AWJ 220uf 25V caps a try (same size as Elna Silmic II and Muse KZ audio caps. These are the highest grade audio caps from Nippon). I found this already an improvement over the ASF caps. But I was still longing for a bit more openness. Well there I put in the 220uf Silmics II.. Immediately the sound got more detailed. Though they still have to run in and I know they will get even a bit better. I lost some bass with the silmics but I got a lot of natural flavored detail back for it.
  
 For opamp position in this circuit:

Nippon ASF - Very VERY buttery and jazzy sound. Forgiving to every genre. I could almost (less detailed) replicate the same sound when I accidentally mistook a 470uf 35V Panasonic FM for a Silmic when swapping caps in the sockets.
Nippon AWJ - More detailed. Still buttery and great lower end extension. Still I was longing for a bit more openness (Didn't give em time to properly burn in, may have opened up a bit more)
Elna Silmic II - Even more detailed. Less bass but great open soundstage without being muddy. Very nice with acoustic snare strikes. A bit more harsh on female vocals but more natural.
  
 I also have some Nichicon Muse KZ in the 220uf 25V lying around.. I am really happy with the Silmic II sound so I didn't try them. But for the sake of completing a full roundup of the major (reasonably priced) high-end audio grade caps, maybe I should try them too..
  
 Also put in some ClarityCaps. Not sure about the improvement but I definitely like the overall sound! I can't say for sure what the ClarityCaps did because I hear the Silmics still changing from time to time. But the overall improvement is really great. Again.
  
 Also got my OPA604APs in dual OPA604AP sounds WAY better than OPA2604AP. More on the spot. Less messy. Same good traits as OPA111VMs but a little less forward and more natural sounding.
  
 After a while you forget you are listening to a recording. especially the high bitrate vinyl rips are REALLY doing an amazing job now. Like angels pooping liquid gold in my ears!


----------



## penmarker

Hey guys, how are things?
  
 Recently got the chance to get myself a pair of active speakers and hooked it up to the amp. The preamp out is very useful as I don't have different volume controls for my headphones and speakers. One thing I probably need to mention though is the amp would get pretty hot with the preamp out. Nothing too hot, just very warm to the touch. I'm not too concerned about it.


----------



## Cidious

Yeah the amp is getting quite hot. But it feels nice and comfy to me.. even the volume knob gets nice and warm. It's a delight to touch it to give myself another few liquid gold decibels..

Like angels pooping gold diarrhea in my ears..


----------



## penmarker

It does feel good. And my DAC being tube buffered doesn't help with the heat either. Ha ha ha.
  
 I think I'm due for a DAC upgrade, but I need to upgrade my cartridge first.


----------



## moriez

I sold my LBCL recently and in hindsight it maybe wasn't the best decision. If there's currently anyone out there who considers selling his Lovely Cube send me a PM please.
  
 Edit: divine developments brought me back the Lehmann :]


----------



## vadergr

http://www.ebay.com/itm/ZEROZONE-Update-version-Class-A-Headphone-amplifier-preamp-base-on-Lehmann-amp-/222055428309?hash=item33b388f0d5:g:-aYAAOSwu1VW6RwE
  
 Anyone tried the zerozone clone ?


----------



## drteming

vadergr said:


> http://www.ebay.com/itm/ZEROZONE-Update-version-Class-A-Headphone-amplifier-preamp-base-on-Lehmann-amp-/222055428309?hash=item33b388f0d5:g:-aYAAOSwu1VW6RwE
> 
> Anyone tried the zerozone clone ?


 
  
 Just finished the build of the Zero Zone kit a couple of days ago.  Fun build.  Came with pretty much everything needed, but I had to scrounge around my parts bin for stand-offs for the power switch.  The build went without a hitch.  I never bothered with the NE5532 opamp that it came with.  Instead, I had a couple of 2132's lying around and chucked one in.  The original spec for the Lehmann was a 2134, which is actually a lower "audio" grade of the 2132.  DC offset was around 8 mV for both channels.  The amp pairs very well with my Beyerdynamic DT990 600Ohm.


----------



## listen4joy

need to complete few parts anyone here?


----------



## folkeb

I've just got my LC up and running (prepopulated pcb). It sounds great, and especially with my dddac and srh940. Anyway, I'm thinking of how I can modify this amp and I have a few questions. I appologize if these have been answered before. 1) I have several black gate N caps. What voltages are required for the opamp decoupling caps? I have 470uf 16v and 100uF 50v. 2) does anyone have a circut diagram? 3) i was thinking of obbligato caps (have 4.7, 6,8 and10uf)as input caps (to replace the stock mkt's). Any comments?


----------



## folkeb

My take on a casing...I know it should be metal, but it is rather nice to see the stuff that makes music ☺


----------



## drteming

folkeb said:


> I've just got my LC up and running (prepopulated pcb). It sounds great, and especially with my dddac and srh940. Anyway, I'm thinking of how I can modify this amp and I have a few questions. I appologize if these have been answered before. 1) I have several black gate N caps. What voltages are required for the opamp decoupling caps? I have 470uf 16v and 100uF 50v. 2) does anyone have a circut diagram? 3) i was thinking of obbligato caps (have 4.7, 6,8 and10uf)as input caps (to replace the stock mkt's). Any comments?


 
  
 The diagram and BOM are listed on page 2 of this thread in this post: http://www.head-fi.org/t/501046/the-lovely-cube-headphone-amp-lehmann-black-cube-linear-clone/15#post_6784844


----------



## folkeb

Hi, thanks. However I still need help to find what the minimum voltage the decoupling caps for the opamps need to be. Can I use black gate 100uf 16v in this position? Also is 4.7uF on output ok, or should I stick with a lower value as per the bom. I should point out that I have no output cap on my dac... Thanks for any answers.


----------



## nicusim

I am a bit confused about where to place the zener diode ,which resistor will be replaced.


----------



## jbaldam

Hi, I use my cube mainly as a preamp using the cd5005 for phones.
 Is there a way to permanantly disable the headphone out circuitry as I need to wind the volume right up for my AKG phones and I am concerned that I will forget and switch the amp on at almost full volume.
  
 Would the lack of the phones facility improve the sound of the cube.


----------



## drteming

I've been playing around with the components and finally settled on the final configuration.  I got a new board off of that large on-line marketplace and got the parts from Mouser and Digi-Key.  
  


  
 For the opamp, I did a blind test, putting a piece of electrical tape over the top of the chips I had on hand (OPA2134PA, OPA2227PA, OPA 2107AP, AD823AN, JRC2068D, and NE5532P).  Signal chain was as follows:  Foobar2000 on a Windows 10 machine -> USB to S.M.S.L M8 -> Zero Zone amp -> Beyerdynamics DT990 600 ohm, AKG K7XX, and AT ATH-M50X.  Music was as follows:  Donald Fagan The Nightfly (SACD-DSF), Dire Straits Making Movies (SACD-DSF), Pink Floyd WYWH (SACD-DSF), Porcupine Tree Fear of a Blank Planet (24 Bit 48 KHz), Daft Punk Random Access Memories (24 Bit 88 KHz), and Infected Mushroom Converting Vegetarians II (Redbook FLAC).  In all honesty, with the blind test, I could not reliably tell a difference between the chips, so I stuck in the one with the least DC offset which was the AD823AN with 4.7 mV on the left and -1.5 mV on the right (with the range going from 4.7 mV to 5.4 mV for the left channel, and -3.3 mV to -1.5 MV for the right channel.


----------



## mikaelmark

A couple of weeks ago, I finalized my portable LC amp by replacing the 4 pcs power supply caps from 100uF Muze KZ to Panasonic FR 1000uF 25V and 2 pcs Elna from 470uF to 220uF (measured paired 228uF).
  
 So, here is a summary of my portable rig (carried in a backpack, driven by 14 pcs AA 2000mAh NiMH batteries):
  
 The amp are connected to the source, a FiiO X5 with 2 x 64Gb Micro SDXC with FLAC´s, with a gold plated 3,5mm/2 x RCA OFC cable and RCA´s are preparred with Cardas contact conditioner. From those, the Mundorf MCap EVO bypassed with FT-1 teflon caps are soldered directly between the incoming RCA´s and the DALE 24 step ladder volume pot with shielded OFC wires (not soldered to the board).
  
 To make a virtueal ground for the batteries, I use a THE2426 rail splitter/ground generator. Also, I did the Zener mod and excluded the 4 power supply resistors, the 2 PPTS fuse and also the 4 rectifier diods.
  
 Finally, the the female phono jack are also soldered with some OFC cable to minimize resistance and connected to my AKG K702 single sided UP-OCC cable modded phones.
  
 Other parts used in the amp: dual THS4031 mono OpAmp with 0,1uF caps, Mundorf MLytic 10000uF, BYV27-200 with MKP10 0,1uF, polystyrene caps and all resistors are Holco HP4 or DALE (except for LED´s), all assembled in a DIY aluminum enclosure.
  
 And when listening with the X5 to low output, the 50K volume pot are only about 12´clock, I have to say the sound are magnificant - so detailed and sweet with an adorable sound stage. Really enjoying!


----------



## mikaelmark

Just to be 100% shure before connecting a toroidal transformer 50VAC 15 - 0 - 15 to the LC, please confirm below is the correct way to do it if it´s connectoed to 230VAC wall outlet (europe), thank´s. And should the purple wire be connected to chassi earth?


----------



## drteming

The output side is correct.  The split coils on the input side should be connected in series if you are on 230V.  One of the red and one of the black wire should be connected together, but not to ground earth like you had drawn.
  

  
  
 The purple wire is the screen lead.  I hooked mine (yellow and green) up to the ground on the board (grounded to chassis), which is hooked to ground earth (yellow).


----------



## Konstantin690

mikaelmark said:


> Just to be 100% shure before connecting a toroidal transformer 50VAC 15 - 0 - 15 to the LC, please confirm below is the correct way to do it if it´s connectoed to 230VAC wall outlet (europe), thank´s. And should the purple wire be connected to chassi earth?


 
  
 Do not connect it like that, it will go BOOOOM!!!
 Are you on 115v or 230v mains?
 For 115v mains, connect the two RED wires together and the two BLACK wires together, connect the two formed pairs on the SIDE PINS of the IEC mains connector, center PIN is Ground.
 For 230v mains, connect one RED and one BLACK together, insulate them and leave them there, now, connect the two remaining cables one RED and one BLACK on the side PINS of the IEC connector.
 The PURPLE wire is the electrostatic shield, connect it to Chassis GROUND.


----------



## mikaelmark

konstantin690 said:


> Do not connect it like that, it will go BOOOOM!!!
> Are you on 115v or 230v mains?
> For 115v mains, connect the two RED wires together and the two BLACK wires together, connect the two formed pairs on the SIDE PINS of the IEC mains connector, center PIN is Ground.
> For 230v mains, connect one RED and one BLACK together, insulate them and leave them there, now, connect the two remaining cables one RED and one BLACK on the side PINS of the IEC connector.
> The PURPLE wire is the electrostatic shield, connect it to Chassis GROUND.


 

 Ok, thank´s!
  
 So it is gonna be like this:
  
 Please forget what I wrote earlier today, below is the correct wiring instruction:
  
 Connect one RED wire to L at the IEC and one BLACK wire to N at the IEC.
  
 Connect the leftover RED and BLACK with each other, but do NOT connect those to the IEC ground.
  
 Connect BLUE wire to one of a hole at the side at the board and GREEN wire to a hole other side.
  
 Connect the leftover BLUE and GREEN to the middle holes.


----------



## Konstantin690

mikaelmark said:


> Ok, thank´s!
> 
> So it is gonna be like this:
> 
> ...


 
  
 Right, that's correct for 230v mains.


----------



## francisdemarte

Can't believe this thread is still going after all these years. I'll be adding Cidious's thread on diyaudio.com to the first page:
  
 http://www.diyaudio.com/forums/headphone-systems/285380-headamp-upgrading-lehmann-bcl-clone.html
  
 and this thread about resolving hum on a defective board:
  
 http://www.diyaudio.com/forums/headphone-systems/271057-100hz-hum-lehmann-linear-clone.html


----------



## penmarker

I was searching the Lehmann Black Cube Linear for fun on Google and I found this link. Its a reviewer that I regularly visit, and it seems that the Linear headphone amp comes with a companion power amp for speakers called Lehmann Stamp
  
 http://www.tnt-audio.com/ampli/stamp-linear_e.html
  
 And the product page.
 https://www.lehmannaudio.com/power-amplifiers/stamp.html
  
 So... next project maybe?


----------



## uncola

is this audiofeel opa301 mk2 a suitable opamp to try in the lovely cube or other lehmann clones?  says it can take 18v


----------



## ChrioN

Anyone measured the temperature inside their amp enclosure? Electrolytic capacitors' rated lifespan are cut in half with each increase of 10 °C (some at 5 °C intervals). No wonder they put caps rated at 12000 hours in this.


----------



## penmarker

I've never measured properly before, but laptops can run for days and days on higher temperatures so I'm not worried.


----------



## ChrioN

All I'm saying is don't cheap out on the electrolytics.


----------



## philcrack23

Hey, i found rare old unused blue 1µ 250 v Epcos MKP, Siemens 0,15µ 250 V Silver Layer for my LM Path.
 Two very large dark pink Wima MKP 10 2,2µ 250 V. The capacity is verry good with the old Label Print.
 Continue, i replaced everything from China Man.
 Then I found to, jellow Wima FKC.


----------



## tl13m

Hi there,
  
 Any one try Burson V5 or SS3602 opamp? How does the sound change? is it easy to fit?
  
 Thanks


----------



## penmarker

I have tried the Burson V5, the difference is subtle enough for me to question myself whether its an improvement or in my head.


----------



## tl13m

penmarker said:


> I have tried the Burson V5, the difference is subtle enough for me to question myself whether its an improvement or in my head.


 

 Thanks,
  
 What is your Lovely Cube stock opamp? Can you put the cover back after install the V5 inside? any heat issue?
  
 I've good impression with V5i for my ZxR soundcard:
  
http://www.head-fi.org/t/623079/creative-sound-blaster-new-series-z-zx-zxr/3270#post_12985681
  
 Maybe because I replaced all 4 stock opamps and I have a reference system for comparison, so it is much easier for me to detect the improvement.


----------



## penmarker

tl13m said:


> Thanks,
> 
> What is your Lovely Cube stock opamp? Can you put the cover back after install the V5 inside? any heat issue?
> 
> ...



My stock OPA was the 4562NA, upgraded by its previous owner. And the cover comes back on with a few mm clearance so don't worry about it. I've recently upgraded my DAC so I might try to do some detailed comparison between the V5 and the 4562. My previous Aune T1 wasn't resolving enough.
There wasn't any heat issues too. I mean if there is, I didn't notice it. The amp already does run quite warm even before the OPA upgrade.


----------



## tl13m

I've switched to V5i today, previous op-amp was OPA2111AM, installing on Lovelycube much easier than soundcard ZxR.
  
 V5i is way more musical than OPA2111AM
  

  
  

  

  
  
 My office setup:
  
 idac2 > Lovely cube > iem/earbud


----------



## uncola

Wow nice to see to13m. I'm going to try an audio feel opa3301 in a Lehman clone this week... hopefully it's compatible


----------



## tl13m

uncola said:


> Wow nice to see to13m. I'm going to try an audio feel opa3301 in a Lehman clone this week... hopefully it's compatible


 
 Hi,
  
 Where did you brought it? is it from this site?
  
http://www.ebay.com/sch/audiofeelccdt/m.html?item=282202265759&rt=nc&_trksid=p2047675.l2562
  
 The web site has a list of op-amp models, what is the different between them?
  
 I'm wonder how they can compete with Burson or Sparko Labs. Please share your finding.


----------



## uncola

the differences are listed in the auction bodies.. I'm not very technical but some models won't work in unity gain and some have dc offset trimpots.. headphone amp isn't unity gain so I think 3301 is compatible but it would be great if someone technical were to confirm


----------



## tl13m

Has anyone upgrade standard Voltage Regulator in LC to Discrete Voltage Regulator (DVR)? Any good?
  
 I read from Nord Acoustics website, their product use discrete voltage regulator
http://www.nordacoustics.co.uk/product-page/a1659afc-ba55-1b1f-f758-7483a08b9287
  
_"Ultra low noise with fast transient responses they sit at the heart of our Nord UP input board providing power to the NC500 and Op Amps. They deliver much of the low level listening ability, soundstage and high end organisation benifits._
_The noise specification of the discrete regulators are vastly superior to standard 78XX and 79XX devices. This is made possible by heavy filtering on the internal voltage reference which requires large capacitors that cannot be implemented on standard monolithic designs. Such luxuries are only possible with discrete designs.  While nose specs are important, regulator performance is mostly about transient response and input rejection. Having a fully discrete error amplifier allows for extremely high input rejection and unique compensation techniques that cannot be implemented with standard monolithic IC error amplifiers . I really noticed the benefit of these at low listening levels, detail and dynamics remain, while at high volumes the clarity stays at far higher levels."_


----------



## tl13m

Installed SS3602 in LC today
 Sadly, it pickup some noise, especially in the left phone 
	

	
	
		
		

		
			





  
 Is it because wifi hub nearby? Has anyone experienced this problem? how can you fix it?
  
 Update: 19/11/16
 Tested with HE 560 and ATH M70X
  
 - The noise only happen with easy drive phone (inear, earbud, ATH M70X)
 - HE 560: no noise, sound absolute beautiful


----------



## tl13m

V5 fit perfectly inside Lovely Cube (remove DIP8 socket come with it)


----------



## alvin1118

Just got this from my vendor, setting the gain to +10dB for HD800.

  
 Planning to swap the OPA2134 to something else. I've OPA627BP and LT1028ACN8 (bought them 8years ago during the AMB Lab Mini3 era!). Need to get some bass back from the HD800.

  
 Sexy isn't it?


----------



## tl13m

alvin1118 said:


> Planning to swap the OPA2134 to something else. I've OPA627BP and LT1028ACN8 (bought them 8years ago during the AMB Lab Mini3 era!). Need to get some bass back from the HD800.


 
  
 If you want get some bass, highly recommend the V5 from Burson.
  
 Cheers


----------



## alvin1118

Thanks mate. 
  
 There is a Burson v5i, any audible difference?


----------



## tl13m

alvin1118 said:


> Thanks mate.
> 
> There is a Burson v5i, any audible difference?


 
  
 I don't have OPA2134. But from the Opamp thread and sound card ZxR, you can see discrete op-amp is better IC opamp (and more expensive).
  
 You can read [u][color=rgb(0, 102, 204)]newdoughboy[/color][/u] comparison for OPA2134 and V5 here:
  
http://www.head-fi.org/t/784790/burson-supreme-sound-audio-v5-opa-d-v5-opa-s-review/15
  
 If you go for Burson, just save it for V5 (not V5i)
  
  
 Cheers


----------



## penmarker

Does the signal go through the opamp when used as preamp out?


----------



## tl13m

penmarker said:


> Does the signal go through the opamp when used as preamp out?


 
  
 I'm not sure, but you can check yourself by remove op-amp and see if preamp mode work.


----------



## philcrack23

Does not work, you can separate from the volume control, with another preamplifier, to the power amp.


----------



## nippon

My LC is still living on my desk and powers my AKG K712 just fine.
  
 First i used the OPAs in this order:
  
 BB2134
 BB2132
 LM4562
  
 The 4562 was quite better, than the 21XX OPAs, but after 2 years he started to make noises and the channel balance was unstable.
 I recabled all wires and connectors and out of perplexity, because the problem didn't disappeare, i swapped the OPA with a OPA2604. Not bad.
 Yes, it's no pricey highend OPA, but offset and sound quality of the chip are way better (sounding) in this circuit, as 2132, 2134 or LM4562.
  
 A cheap upgrade i noticed, just because all other OPAs in my box where broken or junk


----------



## penmarker

philcrack23 said:


> Does not work, you can separate from the volume control, with another preamplifier, to the power amp.


 
 This sentence seem fragmented. Can you elaborate?
  


tl13m said:


> I'm not sure, but you can check yourself by remove op-amp and see if preamp mode work.


 
 Will it be alright if I turn the unit on without an opamp? I'm not too technically competent.


----------



## tl13m

penmarker said:


> Will it be alright if I turn the unit on without an opamp? I'm not too technically competent.


 
  
 Without op-amp I'm pretty sure headphone out will not work, but not sure preamp mode.
  
 When install/replace op-amp, you must make sure:
 - Type: dual
 - Max voltage support: for Lovely cube should be >=15V
 - Direction: half moon mark (or pin 1)
 - Space


----------



## tl13m

alvin1118 said:


> Thanks mate.
> 
> There is a Burson v5i, any audible difference?


 
  
 V5 has more airy (space, sparkling high) than V5i. For Lovely cube make sure you order Dual version. When install it, you might want to remove the DIP8 socket come with V5.
  

  
  
 You also might try the Cable +, they use V5i inside so it will further improve bass weight.
  
 BTW, if you worry about heat (if you live in hot country) you might try this


----------



## penmarker

Don't need to worry too much about heat. Class A amps do tend to get quite hot. Electronic components can stand very high temperatures, that's why some laptops that overheat can be too hot to touch but still run. The amp won't be that hot though so it should be ok.
 I'm running on Burson V5 too. Surprised it can fit well with no space problems. Though the improvement is subtle from my previous 4562, I can't switch back anymore.
  
 What DAC are you pairing it with?


----------



## sunneebear

penmarker said:


> Don't need to worry too much about heat. Class A amps do tend to get quite hot. Electronic components can stand very high temperatures, that's why some laptops that overheat can be too hot to touch but still run. The amp won't be that hot though so it should be ok.
> I'm running on Burson V5 too. Surprised it can fit well with no space problems. Though the improvement is subtle from my previous 4562, I can't switch back anymore.
> 
> What DAC are you pairing it with?


 
 There have been a few of those V5's melting in the Gustard H10.  Some users have posted pictures on that thread.  Some even have opamp failure, not just melting.


----------



## penmarker

Sounds like defective equipment.


----------



## penmarker

Yesterday I found out that the gain switches affect the pre-out too. Got them hooked as a pre to my DIY power amp and speakers, and the volume changed significantly.
 Another thing is the switches has some play and when changing the gain settings, there were some continuity problems. Its fine I guess, I'm not changing them more than once.


----------



## uncola

Anyone have to reduce gain to get a burson opamp to work?  I have a lehmann variant and I swapped stock opa2134pa with burson v5i and I had to go down to 10db to make it work.. it's still loud enough and there's a nice improvement in sound.. just wondering about anyone elses experience


----------



## philcrack23

I have already tested:
 LME 49720NA, OPA 2604 and two 604, OPA 2134, NE 5532P, OPA 2111AM...
  
 Has someone already tested the MC 33078?
 Got an old motorola and he runs absolutely great.
 This is almost unbelievable what the performance comparable to an OPA2111. I paid $ 3 for the 33078 old stock


----------



## mikaelmark

penmarker said:


> Yesterday I found out that the gain switches affect the pre-out too. Got them hooked as a pre to my DIY power amp and speakers, and the volume changed significantly.
> Another thing is the switches has some play and when changing the gain settings, there were some continuity problems. Its fine I guess, I'm not changing them more than once.



Will the pre-out benefit with higher voltage and/or amperes/watts and will it get higher power to the speaker amp? (also with 0 db gain). And is it possible to get better sounds compared just connect the DAC directly to the speaker amp?

As I have a pair of Bower and Wilkins 683 S2 (200 Watt/each) paired with a Yamaha RX-V 771 AV receiver (rated 2 x 95 Watt), I will be happy if it´s possible to get more power from the receiver.


----------



## penmarker

mikaelmark said:


> Will the pre-out benefit with higher voltage and/or amperes/watts and will it get higher power to the speaker amp? (also with 0 db gain). And is it possible to get better sounds compared just connect the DAC directly to the speaker amp?
> 
> As I have a pair of Bower and Wilkins 683 S2 (200 Watt/each) paired with a Yamaha RX-V 771 AV receiver (rated 2 x 95 Watt), I will be happy if it´s possible to get more power from the receiver.


In my experience, the gain increase is only making it louder. There isn't any improvements in terms of sound quality. If your power amp doesn't have the power to drive a pair of low sensitivity speakers, it will remain that way.

And a friend of mine prefers an active pre compared to a passive pre between the DAC and power amp. Citing him, he describes the sound as dry and uninteresting compared to an active pre. I haven't tried bypassing the Lovely Cube as a pre yet so I can't comment much.


----------



## mikaelmark

Ok, thank´s for your clarifying!

And I assume the Lovely Cube are Active, am I right?

And do you think it´s possible for the output voltage from the pre-am to be too high for the power amp/receiver as the receiver have integrated kind of pre-amp?


----------



## penmarker

Yes the Lovely Cube are active. Passive pres usually attenuate the volume using volume pots or stepped transformers. They don't require power and controls the sound by trimming down the level.

Preamplifiers are line stage equipments, that means their output is limited to line level. Line level is loosely standardized because the preamp output can be anywhere between 2Vrms and peaking at 10Vrms. Due to this, power amplifiers are also designed to receive a wide range of output levels. Basically the higher the pre-output level, the louder it is, and the more susceptible it is to noise.

Vintage pre-amplifiers are usually the ones with higher output levels, modern equipment should have no problem. However, the quality of the audio will be a result of overall quality of the preamp and NOT its Voltage output (as long as one avoids the too-little or too-much situations).


----------



## mikaelmark

I have now purchased 4 pcs (2 pairs) of Bursons new OpAmp V6 Vivid dual, and waiting for them to arrive!

A big thumb´s up to the Bursonaudio´s costumer support, that are very handsome and easy to do with!!

But I´m a Little bit confused, as this will operate at a minimum of +-3,5/7 VDC.

As the Lovely Cube only has 5 Volt to the OpAmp, will i be enough to operate the V5 and V6? Or is 7 VDC including +3,5 AND -3,5?


----------



## penmarker

Not sure about the V6 but my amp has the V5 and it works well.


----------



## mikaelmark

mikaelmark said:


> I have now purchased 4 pcs (2 pairs) of Bursons new OpAmp V6 Vivid dual, and waiting for them to arrive!
> 
> A big thumb´s up to the Bursonaudio´s costumer support, that are very handsome and easy to do with!!
> 
> ...


My fault; The OpAmp should receive +-15 Volt, so it should be fine!


----------



## mikaelmark

About setting the Burson V5/V6 into Class A, the simple way we DIY:ers are use to, with two resistors to the output, Burson are not recommending to use BIAS Class A due to the risk of overheating and the fact the discrete OpAmp are FET.

But one question still remain: Are the V6 already Class A from the factory?


----------



## mikaelmark

I have now received my four V6´s and they where shipped in a Jiffy bag (bubble wrapped envelope) from Hong Kong and directly into my letter box.

I have now installed the first V6 into my battery driven Lovely Cube and Everything seem´s to be fine. As I only listen for about one hour at low volume, I can´t comment closer for the sound, but will be back later.

As something has happened with my AKG K702 (they have absolutely no bass), I had to listen to my HD800 instead.

Raoultrifan gave me following explenation about V6 into Class A:

As V5 and V6 opamps are having a quiescent current of +/- 14mA this means these babies will work in pure class A until the output current gets to +/-14mA; after this value the Bursons V5/V6 will work in class AB, per their internal design. Sparko's opamps are working in class A until output current gets to +/15mA, so figures are quite alike and I'd say the +/-1mA difference should not matter in sound quality.


----------



## mikaelmark

Now I´m pretty sure what has happened; The ground Connection between the RCA in-connectors and the PCB was cutted when I putted in the V6 and lifted the board, so the headphones played at very high volume and it was not adjustable.

I turned off the amp after a few seconds, but the K702 seem´s to been damaged as the sound are as listen to only tweeters and distorted at the right ear.

Have mailed Harman/AKG for new drivers.


----------



## candysound

hi

was looking into this amp to try it out and came across this http://www.ebay.co.uk/itm/Finished-LA5se-MOS-FET-Pure-Class-A-Headphone-Amplifier-HiFi-Headhpone-AMP-BLACK/272690293788?hash=item3f7d9bac1c:g:SRUAAOSwGJlZKk1j 

is it the same one ?

also there is this one http://www.ebay.co.uk/itm/L6120Balance-TPA6120-program-balance-headphone-amplifier-Hifi-fever-balance-amp/272781916676?_trkparms=aid=111001&algo=REC.SEED&ao=1&asc=20160908131621&meid=5e55d072b7cc4140950a3dec4ac671c3&pid=100678&rk=3&rkt=12&sd=172517496337&_trksid=p2481888.c100678.m3607&_trkparms=pageci%3Aced85928-8b57-11e7-98a7-74dbd180dc33%7Cparentrq%3A2502bf3615e0a9c4d7483bc2fffb2cd9%7Ciid%3A1

which is quite powerful aswel , wonder if anyone tried it


----------



## penmarker

Both of them are different. The second one is even more different as it has a balanced circuit. You can put "Lehmann" as a keyword when looking for it, there might be some components changed for economical reasons, but the circuits should be the same. If you're technically inclined you can swap them out with better or genuine components.


----------



## SONYES (Aug 31, 2017)

I have the original BCL
And the Chinese imitation
With a huge upgraded power supply
And there is no comparison

Of course the original several degrees above it all


----------



## Konstantin690 (Aug 31, 2017)

SONYES said:


> I have the original BCL
> And the Chinese imitation
> With a huge upgraded power supply
> And there is no comparison
> ...




Done the same "comparison" a couple months ago at a friends house, they sounded more or less the same, but he did not bought an assembled clone, got only the PCB and chassis and sourced the parts from MOUSER.
Both had the input signal capacitors removed.
There are a bunch of counterfeit BD139/140 in Ebay.


----------



## SONYES

Konstantin690 said:


> Done the same "comparison" a couple months ago at a friends house, they sounded more or less the same, but he did not bought an assembled clone, got only the PCB and chassis and sourced the parts from MOUSER.
> Both had the input signal capacitors removed.
> There are a bunch of counterfeit BD139/140 in Ebay.


I have clear differences
The original is awesome
The imitation is a good but good gum
The difference is audible


----------



## penmarker

Try checking the components. It's possible the parts are chosen for their price not performance. I've bought a clone or two off eBay, and they gave the bare minimum quality required, and some fake components.


----------



## SONYES

penmarker said:


> Try checking the components. It's possible the parts are chosen for their price not performance. I've bought a clone or two off eBay, and they gave the bare minimum quality required, and some fake components.


Mine was tested by an electronics technician and a practical engineer
The parts are excellent with a significant improvement in the American power supply
All parts are good
This is nothing to run.
I have the BCL source

A member of the forum took exactly the same amplifier and made it excellent with replacement parts
An even higher level, he says
Something amazing in terms of sound and has HD800 like me

Anything possible question of price


----------



## penmarker

If the circuit is similar then there should be no reason why the sound would be worse or different than the original.

But I wouldn't be too worried about it, probably is only 1/10 the cost.


----------



## SONYES

penmarker said:


> cost.


ONLY   COST
NOT SOUND


----------



## mikaelmark

A couple of years ago, I assembled my first BCL amp, with standard metal film resistors and some quite highly rated components and OPA627. I did sell it to a head-fi member for about $100, and he was very happy with it and praised the black backround of the sound.

After that, I have assembled one portable with batteries, one with an one more with an big toroid transformer (assembled in two Power supply cases for PC) and one more amp is half assembled, using PRP9372 resistors.

For my two amp´s, it has Holco H4P, Mundorf, Audyn True Copper, Russian Teflon, Polystyren, Polystyrene, Genuine LM317/337, BD139/140-16 (note it´s -16, not -10) and 24 stepped Dale volume attenuator. See my earlier post in this thread for more detalis.

I also implement the Zener diod mod and used OPA627 and THS4032, that I´m at this moment just replacing with Burson V6 Vivid. All I can tell is the sound are terrific and when good components are used and are assemled well, one should not be dissapointed!


----------



## leeperry (Sep 6, 2017)

I plan on rolling the two big caps in my 2.21 Mstage, I guess those Mundorf 63V 4700µF M-Lytic's are game-enders? Their ESR figure looks better than everything else I've looked up 



mikaelmark said:


> I´m at this moment just replacing with Burson V6 Vivid. All I can tell is the sound are terrific



No DC offset? V5 gives +15mV in Mstage IIRC.


----------



## mikaelmark

Yes, the Mundorf caps are nice. Don´t forget you can go higher in the capacitance, I have 10000µF in my LBC.

Just remember to measure the space, so they will fit in your enclusure.


----------



## leeperry (Sep 9, 2017)

10K huh? Is this a good thing to go that overboard compared to the 4700uF stock one?

I also noticed that this italian one comes with slightly better ESR(30>29) than the 63V Mundorf: https://www.elcoteam.com/privati/condensatore-elettrolitico-kendeil-4-700-f-63vdc.html

Anyyway, I opened a thread on diyaudio: http://www.diyaudio.com/forums/solid-state/312131-rolling-caps-bcl-clone.html


----------



## mikaelmark

Higher capacitance value in this Power stage position will give more "umpf", but the downside may be less coherence/musicality.

Just be sure not to go lower than 25V.


----------



## leeperry (Sep 9, 2017)

yeah I was afraid of playing God messing with capacitance, I love my pimped mstage as is and those 4700uF/63V Mundorf's look like a safe bet 

this guy went 40V: http://www.ebay.com/itm/Matrix-M-Stage-Headphone-Amp-/272769628145

I guess I can safely go 63V? It'll fit.

And should I roll the half dozen of 470uF/25V as well while I'm at it? https://cdn.head-fi.org/a/2364018.jpg

I see that ebay dude got 470uF/35V caps, I only got 25V huh 

Eventually I've bypassed all DC decoupling input caps and will install pure copper RCA sockets


----------



## SONYES

These improvements are amazing
Thank you all for sharing
Increases the BCL to high levels


----------



## mikaelmark

63V for 4700uF filter cap´s will be fine and also 25V instead of 35V for the six cap´s.

The only thing to note (except size) is when having less Voltage value the lifespan will shrink and when increasing the Voltage it may generate more noise.

Also note that the four cap´s nearest the BD139/140 is in the Power stage and the two nearest the OpAmp IC is in the signal path. So if you will not go with for example Nichicon or Elna for all of them, I recommend Panasonic FR or FC for those four and Elna Silmic II or Nichicon KZ Muse for the two (just remember those may be big in size).

You can also decrease the capacitance value to 220uF for the two in the signal path, if you want.


----------



## mikaelmark

What Components have you replaced and did you hear any difference vs your first listening test?

And have you compared it now again to your original BCL?


----------



## Konstantin690 (Sep 10, 2017)

mikaelmark said:


> Also note that the four cap´s nearest the BD139/140 is in the Power stage and the two nearest the OpAmp IC is in the signal path. So if you will not go with for example Nichicon or Elna for all of them, I recommend Panasonic FR or FC for those four and Elna Silmic II or Nichicon KZ Muse for the two (just remember those may be big in size).
> 
> You can also decrease the capacitance value to 220uF for the two in the signal path, if you want.



According to the published schematic there are no electrolytic capacitors directly in the signal path, all six smaller capacitors are local PS.


----------



## leeperry (Sep 14, 2017)

All discrete opamps I've tried give outrageous DC offset in mstage, could I also play around with the screw on top of those blue components then? https://www.head-fi.org/threads/the...cube-linear-clone.501046/page-63#post-7979213

mstage got two: https://cdn.head-fi.org/a/3836128.jpg

I really wish that HDAM knock-off discrete opamp would work in my BCL knock-off ^^


----------



## penmarker (Sep 14, 2017)

leeperry said:


> All discrete opamps Ive tried give outrageous DC offset in mstage, could I also play around with the screw on top of those blue components then? https://www.head-fi.org/threads/the...cube-linear-clone.501046/page-63#post-7979213
> 
> mstage got two: https://cdn.head-fi.org/a/3836128.jpg
> 
> I really wish that HDAM knock-off discrete opamp would work in my BCL knock-off ^^


From the topology I believe that's the trimmer you adjust to set the output voltage for the power supply. BCL uses a fairly common LM317 regulator circuit and the trimpot allows you to fine tune the output voltage. IT IS NOT for the headphone stage bias (in my opinion).
DO NOT MESS WITH IT unless you have at least a multimeter. Class A circuits run with the gates always off, hence the heat. You can very easily fry components.

**Edit
Both the BCL Clone and Matrix M Stage could be using a LM317/337 with a V+/0/V- voltage rail, but Mstage is allowing you to adjust both the 317 and 337 voltage hence the two trimpots, while the BCL only allows to adjust 317 to match the 337 voltage. I assume Lehmann engineers already know how to get an accurate voltage output with static components so they only need one trimpot to fine tune 317 (V+) to match 337 (V-).

Don't be too bothered about DC offsets, they're not be all end all measure of sound quality. Discrete opamps has more components and each has their own tolerances. IC opamps can be made within stricter tolerances due to the accuracy when it comes to microprocessor production.


----------



## Mad Max

Those trimmers are part of the regulators' voltage references.  I saw it recommended in the thread earlier to use them to reduce DC offset - I'm no expert, but I'm fairly certain that we really shouldn't be haphazardly messing with the voltage references at all.  That would screw up the whole amp or just trigger the protection circuitry in the regulators, leaving the amp without power, I'm guessing.


----------



## leeperry

penmarker said:


> Don't be too bothered about DC offsets, they're not be all end all measure of sound quality. Discrete opamps has more components and each has their own tolerances. IC opamps can be made within stricter tolerances due to the accuracy when it comes to microprocessor production.


OK thanks, well Shure beg to differ: http://www.shure.com/americas/support/find-an-answer/maximum-dc-voltage-applied-to-headphones

I was told by a discrete opamp mfr that Mstage can't really play nice with discrete opamps and will always turn into a DC cannon, which is a major bummer coz I really dig that HDAM knock-off


----------



## mikaelmark

Your statement are correct, those two 470uF nearest the Opamp are connected between OpAmp and ground.

But if all six cap´s are in similar Power supply position, why do many people using Elna Silmic II for those two nearest OpAmp?

Do you think it will be better using for example Panasonic FR also in this position? Should I replace my Elna Silmic II?


----------



## penmarker

mikaelmark said:


> Your statement are correct, those two 470uF nearest the Opamp are connected between OpAmp and ground.
> 
> But if all six cap´s are in similar Power supply position, why do many people using Elna Silmic II for those two nearest OpAmp?
> 
> Do you think it will be better using for example Panasonic FR also in this position? Should I replace my Elna Silmic II?


You should try and report back. They're cheap enough to buy and keep as spares if doesn't sound too good.


----------



## penmarker

I don't have my amp with me now, but can someone check if the preamp out the same as the headphone out?

I am asking because there are some other amps built by people with pre out connected to the headphone outs.


----------



## mikaelmark

The Pre Out is intended to be connected to a separate speaker amp. So maybe there is different impedances between Pre Amp Out and Headphone Out.

And also note that the volume Control and gain switches will affect the Pre Out.

I have tried use it myself, by not really convinced why to use the LBC as a Pre Amp, as the speaker amp´s today will not need it. Back in the day´s with vinyl player´s and Phone out, it should be another story.


----------



## penmarker

I am using the LBC as a preamp to my clone Naim NAP200 power amplifier. I'm planning to build another headphone amp and using it as a pre as well.

Yes the gain switches and volume do affect the pre out gain as well. It's a pre out, as opposed to line out.

Just want to check whether they tap the pre out from the same headphone out or do they bypass some of the output stages.


----------



## mikaelmark

The pre out is connected from one of the headphone out and only one headphone out will mute the pre out while the other will use headphone out and pre out simultaneously.


----------



## leeperry

mundorf = good stuff


----------



## leeperry (Oct 1, 2017)

.


----------



## leeperry (Oct 1, 2017)

mikaelmark said:


> Do you think it will be better using for example Panasonic FR also in this position? Should I replace my Elna Silmic II?


 470uF 60V Silimc II's are on sale at digikey at 3 bucks a pop, should I get half a dozen or what ? Some claim that KG's or FC's are better for PSU: https://www.google.com/search?q=elna+silmic+or+nichicon+kz

And I don't have a scope so how the hell am I supposed to find out whether an extra wima bypassed on top of those caps would help huh?

I blew a $15 ebay coupon on OPA1622 modules and pure copper RCA sockets


----------



## mikaelmark

I can see you have removed and bypassed the filter cap´s, and this "can" be a good thing for the sound. But be sure you will not have too much DC from your source (less than 50mV, preferrable under 20mV). Ohterwise you can damage your headphones.

And did you use some real copper wire to solder, intended for audio? Remember those are in the signal path. And if should be thick enough to not be a bottle neck. Pieces of interconnect wire will be fine here.

Also, there´s no need to solder both C23 /C24 and C21/C22, only one pari of them should be enough. But it´s ok however, the positive thing is the cable area will be bigger this way.


----------



## Konstantin690 (Oct 1, 2017)

mikaelmark said:


> And did you use some real copper wire to solder, intended for audio? Remember those are in the signal path. And if should be thick enough to not be a bottle neck. Pieces of interconnect wire will be fine here.



Assuming a 2 volt signal (common for Cd players and DACs) in combination with the 50Kohm input resistance, the Current this little piece of wire passes is less than 0.1mA (actually, 0.04mA), so unless you use some extremely thin and very difficult to handle and solder wires (over 34AWG, 0.15mm), there's no way to create a bottleneck,


----------



## leeperry (Oct 1, 2017)

Mimby runs a DC servo and I used OCC wire 

Oh OK, well SQ is great as is but maybe I'll try with only two wires then.

Anyways, what should I try to replace the half-dozen 470uF's then? Apparently SILMIC II aren't all that good for PSU?

Well I've followed steps 1 & 4, willing to try 2 with the extra WIMA's but unsure what caps to use for 3: https://www.head-fi.org/threads/mat...ap-and-excellent.475618/page-122#post-7653108

I've also tried a certified fuse but SQ became mushy so I went back to stock huh.


----------



## penmarker

mikaelmark said:


> The pre out is connected from one of the headphone out and only one headphone out will mute the pre out while the other will use headphone out and pre out simultaneously.


If I understood correctly, the line out is the same as the headphone out?
Is this a common industry practice? From what I understood, pre out and headphone out should be different as you don't want to double amp the power amplifier.


----------



## mikaelmark

OCC is great for low level signal, even better than OFC. I have cryo treated OCC (Ohno Cast Copper) in my modded AKG K702 headphones.

And as you already solder all four wires, there is no need to take any of them away. Just let them be, should be no down effect.

And your statement is correct; Elna Silmic II are not to be used in Power Supply. For those four 470uF cap´s, I will recommend Panasonic FC or even better the newer Panasonic FR - they are among the best here.

And when I´m using glass fuses, I use to solder them for best connection, but it can be a bit tricky; To much heat and they will be destroyed.


----------



## leeperry

A friend of mine advised to go Silmic for opamp decoupling, KW & KA for PSU and to get 1K uF coz ripple is higher and even 470uF was already overkill anyway: https://electronics.stackexchange.c...apacitor-variant-for-opamp-power-rails/237088

Solder glass fuses huh? Might as well use copper foil lol, there's a lot of el cheapo audiophool fuses on ali & ebay but I don't trust them one bit.

That UPOCC wire I used is stranded 24AWG, I'll replace it with solid 20AWG down the road.


----------



## mikaelmark

Konstantin690 said:


> Assuming a 2 volt signal (common for Cd players and DACs) in combination with the 50Kohm input resistance, the Current this little piece of wire passes is less than 0.1mA (actually, 0.04mA), so unless you use some extremely thin and very difficult to handle and solder wires (over 34AWG, 0.15mm), there's no way to create a bottleneck,



I partially agree with that, but why do we audioholics using expensive OFC, UP-OCC, Silver plated Copper etc for speaker, interconnet and heaphone wires and not just cheap "including the buy - licorice cords" or standard high voltage wires? It´s because the audio signal is so sensitive, even a minor loss for the signal will degrade the sound. There are people hearing differences when using a phone plug adapter of bad quality.

And the material used are more important than the thickness area, thicker cables should be used for longer distances.

And the reason most connectors are nickel, gold or even Rhodium plated, is just to minimize the risk of oxidation and with the time it can be bad connections.


----------



## Konstantin690 (Oct 7, 2017)

mikaelmark said:


> I partially agree with that, but why do we audioholics using expensive OFC, UP-OCC, Silver plated Copper etc for speaker, interconnet and heaphone wires and not just cheap "including the buy - licorice cords" or standard high voltage wires? It´s because the audio signal is so sensitive, even a minor loss for the signal will degrade the sound..



What exactly do you mean by "minor loss of signal"?
In your opinion, a 1 inch long 28AWG piece of wire in the signal path will degrade the sound more (been a bottleneck as you said) than a 20AWG?
Why? Because the 20AWG wire has lower resistance than the 28AWG wire?


----------



## mikaelmark

Konstantin690 said:


> What exactly do you mean by "minor loss of signal"?
> In your opinion, a 1 inch long 28AWG piece of wire in the signal path will degrade the sound more (been a bottleneck as you said) than a 20AWG?
> Why? Because the 20AWG wire has lower resistance than the 28AWG wire?


As I wrote in my recently post; For longer wire length, you will need a thicker Cable to be sure to not "loss" too much of the sound (details, coherence, ambience etc). So a 20AWG would be preferrable.

But as I also stated; More important than the thickness and lenghts, is the material it´s made of. Silver is to prefer, but can sound cool to some persons/Equipments, copper is a lot cheaper and almost as good, depending on it´s purity/technology. Aluminum can also be used, but it´s not equeally good to handle voltage signals. There is also a risk of oxidation if using those materials in connectors, especially silver - that´s why mostly gold plating are used. Plain iron should almost always be deselected, that´s why I removed my 2 inch long iron or nickel bleck in my Yamaha receiver and soldered the Van Damme speaker cables directly to the main PCB in the receiver.

But also, Everything depend´s on the equipment, the listeners ear and also the wallet and finally but not least; The belief. So if the listener don´t hear any differences or found a cheaper solution better and believe in that, please feel lucky an go on with that! I don´t want to let this thread be a nasty one arguing about what every person should be using - if someone are using speaker cables  Worth >10.000USD, it may be right solution for that person. I had for example Jenving Supra Sword anniversary edition speaker cables and interconnects, valued about 500USD/each and in my equpment I did´nt found them justified and they are now sold to a person hopefully enjoy them more.


----------



## leeperry

but silver oxide is still more conductive than everything else but silver 

so do you agree to use 1K uF instead of 470 uF for those 6 caps? KW & KA both look yummy for PSU


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## Konstantin690 (Oct 7, 2017)

We were talking about the 1 inch long wire that replaces the two signal caps in the BCL, I don't really understand what the above has to do with it, sorry.



mikaelmark said:


> Remember those are in the signal path. And if *should be thick enough to not be a bottle neck*. Pieces of interconnect wire will be fine here.
> .





mikaelmark said:


> I partially agree with that, but why do we audioholics using expensive OFC, UP-OCC, Silver plated Copper etc for speaker, interconnet and heaphone wires and not just cheap "including the buy - licorice cords" or standard high voltage wires? It´s because the audio signal is so sensitive, *even a minor loss for the signal will degrade the sound*. There are people hearing differences when using a phone plug adapter of bad quality.
> .





You still didn't answer my question.
What exactly do you mean by "minor loss of signal"?
In your opinion, a 1 inch long 28AWG piece of wire (which replaces the input signal caps) will degrade the sound more (been a bottleneck as you said) than a 20AWG?
Why? Because the 20AWG wire has lower resistance than the 28AWG wire?


----------



## mikaelmark

leeperry said:


> but silver oxide is still more conductive than everything else but silver
> 
> so do you agree to use 1K uF instead of 470 uF for those 6 caps? KW & KA both look yummy for PSU


I have tried 1000uF Silmic II for the four caps´s and it worked ok, but replaced them with 470uF Panasonic FR. For the two nearest the Opa, I still have Silmic II 470uF and for one LBC I lowered the valued here to 220uF with good results.

But I´m not totally shure Silmic II will be the best solution, as also this position remains the PS-section (Opa voltage pin´s to ground). Maybe I will try to swap also those for FR´s.


----------



## leeperry (Oct 7, 2017)

Sounds good thanks but I don't plan on dropping +50 bucks to roll 6 caps lol, my friend wants me to go 1K everywhere coz ripple current is highest, you tell me 220 and I planned on going 470 with the highest voltage for better ripple 
You want me to go FC & FR, he wants me to go KA & KW, I wanna try Silmic's for the opamp section anyway so there ya go +$50 of audiophool OCD disaster
	

	
	
		
		

		
			





I' d rather blow that half-benji on furu pure copper RCA sockets for my DAC to match the pair I'll be putting in mstage


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## mikaelmark

Konstantin690 said:


> We were talking about the 1 inch long wire that replaces the two signal caps in the BCL, I don't really understand what the above has to do with it, sorry.
> 
> 
> 
> ...


I first question leeperry if what material he was using for the bypass wire:


"And did you use some real copper wire to solder, intended for audio? Remember those are in the signal path. And if should be thick enough to not be a bottle neck. Pieces of interconnect wire will be fine here."

And he answered he used OCC (I assume maybe UP-OCC), and this is really fine wire and that I told him. I also tell him (and anyone else) there are no must to bypass all four removed caps, but as he now already did, they should be left as is.

But IF he had tell he was using for example CCA or some steel wire, then I/he should be worried regardless AWG, especially if using thinner wire. But I rather use 28AWG OFC/OCC than 14AWG steel wire, also if it´s 1 inch long. Even for small connectors with very short distances, I Believe the sound will be degraded if using bad metal´s - that´s why HiFi-equipment are using brass or copper. Then it´s Another story if you or I hear can hear any difference, but we have physical fact´s and also Believes (not right or fault). 

That´s what I´ve tried to explain to you, Konstantin690!


----------



## mikaelmark

leeperry said:


> Sounds good thanks but I don't plan on dropping +50 bucks to roll 6 caps lol, my friend wants me to go 1K everywhere coz ripple current is highest, you tell me 220 and I planned on going 470 with the highest voltage for better ripple
> You want me to go FC & FR, he wants me to go KA & KW, I wanna try Silmic's for the opamp section anyway so there ya go +$50 of audiophool OCD disaster
> 
> 
> ...


No, oxide is always bad for connection area´s! Hav´nt you (as I) had partially or fully loss of sound because of annoying connectors, and when touching the cable a little, the sound will come back. And old equipment with volume attenuators that will scratch if turning them and if moving them back and forth for a while, they will be a bit quiter when the oxide dissappers a little. Those situations almost always appears because of oxide

Small amount of oxide can be removed with strong alcohol, preferrable about 96% isopropanol or using some Contact cleaner liquid, such as DeOxit or Cardas Contact Conditioner. But those liquid´s should be used with care, because they are conductive and should NOT be used for hight voltage AC wall outlet jacks.

About replacing the four or six caps, a batch of ten pieces of Panasonic FR 470uF, 24V will cost you about $7USD at ebay, incl. shipping. FC are the widely used model, good for for PSU´s, FM are the low ESR model, and some people reporting they are not totally stable. FR are the newer development of FC and should be among the best for this position.

Nichicon KA, KW and FW is intended for audio use, but I´m not shure they will be fine for this PSU position. For example Nichicon Muse KZ are the brand´s top model for audio, but Silmic II should be better.


----------



## leeperry

OK thanks fair enough, did you try to bypass them all will small Wima/Vishay? It apparently yields great results 

Well I got those eichmann bullet knock-off's, wish me luck then: http://www.ebay.com/itm/321757909078

I'm also very impressed by how much a shielded power cable matters to Mstage huh


----------



## leeperry

Actually regarding FR my friend said that it's too low impedance and that once amp has warmed up for a few minutes, I should check and see if the regulators run hotter than with stock caps.


----------



## mikaelmark

The FM -series are known to be very low impedance. The FR should be about equal to FC, but a newer serie with the advantage of very low ESR.

I hav´nt noticed any downsides with my four FR 470uF, 25V.

But now I was googled for it, and someone recommend not using the FR in "bridge rectifier area" for an amp. Can someone confirm/declare if this is the case here!? I know they are in the PSU section and positioned after the rectifier diods before the transistors.

http://rockgrotto.proboards.com/thread/7954/panasonic-fc-fr-capacitors


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## mikaelmark

They stated to be fine for use in Switched Mode Power Supplies, SMPS-technology.

http://diyaudioprojects.com/Forum/viewtopic.php?f=10&t=3018

https://www.gearslutz.com/board/geekslutz-forum/784070-best-coupling-caps-elna-nichicon.html


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## mikaelmark

https://www.computeraudiophile.com/...-mini-review-of-the-singxer-su-1-ddc/?page=18

https://www.head-fi.org/threads/aud...oute-new-devices-opens-up-new-options.822160/

https://penoff.wordpress.com/2017/0...ne-amplifier-part-i-schematic-and-pcb-design/

http://www.diyaudio.com/forums/headphone-systems/204993-capacitors-opamp-power-rails.html

"I do agree that there can be problems when paralleling an electrolytic and a relatively-small cap. But the ESR of the electrolytic isn't usually the problem. Even the "low-ESR" types do not have extremely-low ESR. The small cap's ESR, on the other hand, CAN be a potential problem, such as when a film cap is used there. With its tiny ESR, its capacitance can form an under-damped HF resonance with any stray inductance, such as that of the electrolytic."

"For PSU filters I prefer the newer Panasonic FR (or Nichicon UHW if I want bigger values like 4700uF @25V).
Just be careful not to put them (or any other low ESR cap) after a series regulator like LM78xx or LM317. They will oscillate."


----------



## listen4joy

i just want to say thanks to   *mikaelmark *that helped me a lot to build this amp beofre few months, with good quality parts that will be sound good and close to the original one.
  although i still haven't the chance to compare them one by one..for the price i really satisfied the combo with my HD800 +(SDR MOD), the main differnces will be when you will switch chipamps to tune the sound signature that will fit to your own taste, i only tried 2 of them, anyway i would like to share my own amp to incourge others to build this one and the result can be pretty good.


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## SONYES

listen4joy said:


> i just want to say thanks to   *mikaelmark *that helped me a lot to build this amp beofre few months, with good quality parts that will be sound good and close to the original one.
> although i still haven't the chance to compare them one by one..for the price i really satisfied the combo with my HD800 +(SDR MOD), the main differnces will be when you will switch chipamps to tune the sound signature that will fit to your own taste, i only tried 2 of them, anyway i would like to share my own amp to incourge others to build this one and the result can be pretty good.


Outstanding in your success and stubbornness
Appreciate
Too bad I do not have the original to compare

There is no doubt that the design of the original BCL is one of the best things
To HD800


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## SONYES (Oct 16, 2017)

THANK YOU


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## Mad Max (Oct 16, 2017)

mikaelmark said:


> The FM -series are known to be very low impedance. The FR should be about equal to FC, but a newer serie with the advantage of very low ESR.
> 
> I hav´nt noticed any downsides with my four FR 470uF, 25V.
> 
> ...


The rectifier diodes are right after the transformer, not after the regulators like those 470uF capacitors.




penmarker said:


> If I understood correctly, the line out is the same as the headphone out?
> Is this a common industry practice? From what I understood, pre out and headphone out should be different as you don't want to double amp the power amplifier.


The preamp output, or "pre out" as it is sometimes labeled, should be the same thing as the "headphone out", or "HP out", as far as I know, in most amplifiers that have these.
That is precisely the signal that you want for a power amplifier, as the power amplifier on its own is missing the preamp.  An integrated amplifier has both in one unit.  I don't know if this is "double-amping" (probably not), but that's how it is normally done.  "Double amping" should be something like chaining two preamps together before the power amp.


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## penmarker (Oct 22, 2017)

BlaBlaBla said:


> Quote:
> 
> 6. This is trimmer pot. With it you can tune ONLY POSITIVE VOLTAGE (LM 317) and lower your DC offset.


Hi, this seems a bit peculiar.
I've revisited my amp build and I realized mine doesn't have the trimmer.
Maybe different board version? Mine is straight from AliceMagicBox and not eBay or AliExpress.


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## leeperry (Oct 25, 2017)

so OPA1622 is indeed a major winner but even with no input connected I get 28+40mVDC offset at 10X gain, hell SQ is too good I don't care hah. I was told by a discrete opamp manufacturer that mstage would most likely always become a DC cannon with discrete opamps because "they pull a couple uA of bias current that can cause offsets that then get gained up by the system gain.  Lowering the gain will help" and I guess 1622 isn't too happy either but man this chip is indeed the sheer winner we were promised, 145mA output 

DC offset is 2+7mV at 1X gain but sound is far less percussive ><

Regarding those 470uF caps, I think I'll just go with 6X https://www.digikey.com/product-det...onic-components/EEU-FR1J471/P15415-ND/3072295


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## mikaelmark

penmarker said:


> Hi, this seems a bit peculiar.
> I've revisited my amp build and I realized mine doesn't have the trimmer.
> Maybe different board version? Mine is straight from AliceMagicBox and not eBay or AliExpress.


This mod is an optional upgrade, similar way as replacing two of the four resistors with diodes (as I have done in mine).

I assume this potentiometer allows to trim more exactly the voltage you want.


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## mikaelmark

leeperry said:


> so OPA1622 is indeed a major winner but even with no input connected I get 28+40mVDC offset at 10X gain, hell SQ is too good I don't care hah. I was told by a discrete opamp manufacturer that mstage would most likely always become a DC cannon with discrete opamps because "they pull a couple uA of bias current that can cause offsets that then get gained up by the system gain.  Lowering the gain will help" and I guess 1622 isn't too happy either but man this chip is indeed the sheer winner we were promised, 145mA output
> 
> DC offset is 2+7mV at 1X gain but sound is far less percussive ><
> 
> Regarding those 470uF caps, I think I'll just go with 6X https://www.digikey.com/product-det...onic-components/EEU-FR1J471/P15415-ND/3072295


Just take a note the diameter size of those; 0.492" Dia (12.50mm). As they are rated 60V, they can be quite big, but I think they should fit to the board - but please measure before you buy.

25V and 35V´s diameter is only 10mm, and they will absolutely acceptable in this position. If you chose 35V, you will be totally on the safe side of both Voltage and size. They´re also 2/3 of the price. The only negative are the estimated life span @ 105 degrees Celsius will be 8000 hours instead of 10000 hours for 63V.

https://www.digikey.com/product-det...c-components/EEU-FR1V471B/P15391CT-ND/3072271


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## leeperry (Oct 29, 2017)

Well the higher the voltage rating the higher the ripple and 12.5m will fit everywhere as far as I can tell. I'm kinda looking for game-enders, not interested in saving a few bucks or rolling caps several times in a row. My friend wanted me to go much higher than 470uF but FR is apparently prone to oscillation so I'd rather stick to the original value(which is already overkill FWIR).

I will also have to try that wima bypass trick under the PCB as it's also supposedly a major winner and maybe upgrade them to vishay's later on but man you gotta hear OPA1622 

I'll also try OPA1688 for the hell of it


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## mikaelmark

leeperry said:


> Well the higher the voltage rating the higher the ripple and 12.5m will fit everywhere as far as I can tell. I'm kinda looking for game-enders, not interested in saving a few bucks or rolling caps several times in a row. My friend wanted me to go much higher than 470uF but FR is apparently prone to oscillation so I'd rather stick to the original value(which is already overkill FWIR).
> 
> I will also have to try that wima bypass trick under the PCB as it's also supposedly a major winner and maybe upgrade them to vishay's later on but man you gotta hear OPA1622
> 
> I'll also try OPA1688 for the hell of it


As I suppose you´re amp is functionally working already; What kind of cap´s do you have in it now for those six?


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## leeperry

unsure http://www.imagebam.com/gallery/mcgpqvg8qur89zjlh3p9srdo86ldmrw9


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## mikaelmark

leeperry said:


> unsure http://www.imagebam.com/gallery/mcgpqvg8qur89zjlh3p9srdo86ldmrw9


Oh, those are Panasonic, or rather Matsushita!

But it´s the the M-series.

http://www.hardwaresecrets.com/how-to-identify-japanese-electrolytic-capacitors/3

http://en.globals.social/item.html?...000UF+disassemble+pyrami&key=Filter+capacitor


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## leeperry

Cool, FR's should make for a nice SQ improvement hopefully?


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## mikaelmark

Panasonic/Matsushita are generally of good quality, also their low budget consumer Electronic Equipment, with good spec´s and long life span.

But of course, as the FR´s are the upgraded model in their highly regarded FC and FM family, they should be among the best! Please report back with your experices if you decide to go with the FR.

For the OpAmp, please take a look at the Burson V6 Vivid or Classic, a few pages back in this forum thread. I´ve bought four Vivid after they were newly arrived this summer, and they should be the best in the world - at a cost of 130$. The sound are phonemenal, in both amp´s and DAC´s!

https://www.bursonaudio.com/products/supreme-sound-opamp-v6/


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## leeperry

I'll be rolling FR's within 10 days and 1622 outputs 145mA, nothing touches it IME and yes I've heard Burson V5.


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## penmarker

Currently I got the V5 in my unit, and it sounds good. However since its a discrete opamp inside a plastic case, it does has a temp limit. I read somewhere it was supposed to be 50 celcius.


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## mikaelmark

Yes, I read claims about the temp. problems for the V5 and remember some user told about there was an upgraded version of the V5 to handle heat better, but at the cost of sound quality (read 37mil´s post) https://www.head-fi.org/threads/bur...o-opamps-discussion-and-reviews.854912/page-4

V6 has ventilation holes at the top and when I inserted it in my small DAC, I had to cut a hole in the enclosure to make it fit, and this also let the V6 "breath" more.


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## leeperry

I'm also expecting this thing, will be fun to try but I don't see it killing 1622 huh: https://www.aliexpress.com/item/HDA...module-HIFI-amplifier-module/32819103049.html


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## mikaelmark

I had take a look at this earlier also, but honestly - I don´t believe it´s worth the price.

And don´t forget the horizontal size: 25x32 mm (1inch x 1 1/4 inch). It´s huge!


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## leeperry

price went bonkers after I ordered, I got it for $17 shipped.

should fit, we'll see but it won't beat 1622 anyway.


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## mikaelmark

The LBC amp have a 100 Ohm resistor and a small cap between the signal earth and chassi earth, but not all consumer Equipment are using this technology, especially low and mid buget HiFi.

In my setup, only the DAC are earthed/grounded, and everything connected to it will be grounded by RCA Interconnect cables, but is this enough, or should I connect separate grounding cables from all the equipment (such as receiver) to the DAC?

As far as I know, it is not a good idea to ground all equipment by their own as this can create grounding issues.


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## leeperry (Nov 11, 2017)

Obviously the RCA cables common ground is sufficient to avoid ground-loops so I'm not sure what you're after?

Anyway, I just rolled those 63V 470uF FR caps and I'd venture saying that sonic improvement was well worth the $7 as in more detailed, more bass at low volume and louder center channel. VR's heatsinks aren't getting any warmer either, happy camper here 

I'm not sure if that's how ESR works but anyway I think those caps are indeed faster in the way that nothing gets blurred, not going back to stock 16V cheapies


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## mikaelmark (Nov 11, 2017)

leeperry said:


> Obviously the RCA cables common ground is sufficient to avoid ground-loops so I'm not sure what you're after?
> 
> Anyway, I just rolled those 63V 470uF FR caps and I'd venture saying that sonic improvement was well worth the $7 as in more detailed, more bass at low volume and louder center channel. VR's heatsinks aren't getting any warmer either, happy camper here
> 
> I'm not sure if that's how ESR works but anyway I think those caps are indeed faster in the way that nothing gets blurred, not going back to stock 16V cheapies


Really nice to hear about your improvent with the FR´s!

About the grounding; yes, that´s what I meant - ground loop. To avoid that, I have connected wires from different Equipment to the Power supply chassi of the DAC, that is grounded to the wall outlet. But grounding the Active sub woofer was not good, as this introduces constantly humming.

But as you already stated; Mabye the Interconnect´s will do the job. What I´m afraid of is that EMI and EMF from the chassis will pass the same way as the signal, and I assume that´s why a 100 Ohm resistor and a cap are used - but I do not have this in my Yamaha RX-V771 receiver.


https://en.wikipedia.org/wiki/Ground_loop_(electricity)

http://fms-corp.com/emfemibasics_overview


----------



## leeperry

First day with those FR caps was a little edgy yet very bassy but now it's pure bliss 

RCA cables ground will definitely share all grounds between your audio devices.


----------



## francisdemarte

Just logged in to check and its good to see this thread is still going strong after all these years!


----------



## vrajcevski

assembled this one: 
https://www.aliexpress.com/item/The...32808241455.html?spm=a2g0s.9042311.0.0.pWPfAH 
the parts were really wellmatched - apart from 2 resistors that were wrong ( 68 Ohms supplied instead of 680) but the rest was pretty much spot on - the components supplied were actually wthin 0.1% from each other.  

So - Listened frost with the supplied OPA2134 - I did notice a bit of edginess at larger volumes - both on HD650 and AKG K7xx, AND the case was getting fairly hot. Swapped for LM4562 - better sound overall - not much BUT the edginess was still there  -  and the case was getting pretty warm - Not Hot  BUT warmer than I had liked it. DC offset was really small hovering around 1mv ( probably within the tolerances of my meter). 

So decided to go with an LM 4562HA in a metal can, mounted on a stand and with a heatsink . so - Edginess gone, and after about 1 hour of pretty loud listening, the case is not even luke warm - so it seems possible that the typical OpAmps that I had used - all in a plastic case had some high frequency instability - and the Metal can one is Stable - hence the heat. I guess I will not know till I get and osciloscope. 

In terms of modifying - I think I will hold back on any component swaps - and focus on MAYBE adding a shunt regulator. 

But so far - sounds fantastic I'll just listen for a while till I get itchy fingers and figure out a way how to splice a regulator between the 317/3317 and the rest in an attempt to get the ripple further down. 

Must thank everybody for all the details in this thread


----------



## noobDiyAudio

Hi I just bought a lehmann clone / lovely cube equivalent (board assembled) from eBay. I am currently having an issue where if I plugged my headphone all the way into either of the front 2 headphone jacks, only the right channel works. If I plug it almost in, then both channel works fine but lacks the same sound quality as if I plugged it all the way in (even though it is only 1 channel when all the way in, I can tell the difference). I tried the output at the back and only the left channel works. 

Any help would be much appreciated, I can replace components if need be. Thanks.


----------



## penmarker

Report to the seller and request for replacement. All assembled boards are supposed to be tested before shipped out.


----------



## noobDiyAudio

penmarker said:


> Report to the seller and request for replacement. All assembled boards are supposed to be tested before shipped out.



That is one of the option I am considering. I was just hoping if there's a known fix that exist to avoid going through the whole process of sending it back and waiting for a replacement.


----------



## mikaelmark (Dec 25, 2017)

noobDiyAudio said:


> Hi I just bought a lehmann clone / lovely cube equivalent (board assembled) from eBay. I am currently having an issue where if I plugged my headphone all the way into either of the front 2 headphone jacks, only the right channel works. If I plug it almost in, then both channel works fine but lacks the same sound quality as if I plugged it all the way in (even though it is only 1 channel when all the way in, I can tell the difference). I tried the output at the back and only the left channel works.
> Any help would be much appreciated, I can replace components if need be. Thanks.


A thinkable failure reason to try first is if it´s dirt or oxide at either the phono jack or the socket, you can just clean the connectors metal surface with some alcohol (Isopronanol or similar).

If that will not solve it, you can try this step: As I´ve had a similar problem with mine; there was silence at one channel when touching the headphone cables 6,35 mm (1/4 inch) jack, and it was the phono jacks three metal connectors pressing not firm enough. The solution was to open up the enclosures lid and simply pushing gentle at all the three metal connectors at the female phone socket with a plastic tool.

The last step you can try, if the problem still are there; visually check/measure all solderings to be sure they are good and measure all resistors they have correct values.





Have a Merry Christmas everbody!


----------



## vrajcevski

So Assuming you have had a chance to read through the full thread - as much as it is very long, you need to be prepared to open the case- and if you are- when you do and turn the amplifier on- check that BOTh internal LEDs are on. that would establish that at least to a point you have the power going to both channels. There is no standard published troubleshooting method so first things first - before you get to unscrewing and removing the board to check for cold solder joints or checking for shorts or pressing and squeezing, first vicula inspection that at least you have the voltages in check the internal LEDs. They SHOULD be on, even if you have removed the OpAmp from the socket. In fact witht he AMPunplugged from Power, you could remove the OpAmp, and the 2 LEDs should be on. if they are on, then you can start looking for other things. 

I think earlier in this thread -and i don;t know the post there was a diagram with voltages that can be checked.  Do You have at least a universl meter? they are not expensive and are necessary for any kind of troubleshooting. 

Also - be mindful that the primary of the transfomer is at Grid (High) voltage, and if the safety  case grounding is not properly done it can be lethal.   even if grounded properly, I would feel a  more comfortable with an ELCB protected power point or at least extension cable.


----------



## noobDiyAudio

mikaelmark said:


> A thinkable failure reason to try first is if it´s dirt or oxide at either the phono jack or the socket, you can just clean the connectors metal surface with some alcohol (Isopronanol or similar).
> 
> If that will not solve it, you can try this step: As I´ve had a similar problem with mine; there was silence at one channel when touching the headphone cables 6,35 mm (1/4 inch) jack, and it was the phono jacks three metal connectors pressing not firm enough. The solution was to open up the enclosures lid and simply pushing gentle at all the three metal connectors at the female phone socket with a plastic tool.
> 
> ...



Thanks for the feedback, I measured all resistors, all have  the correct values.



vrajcevski said:


> So Assuming you have had a chance to read through the full thread - as much as it is very long, you need to be prepared to open the case- and if you are- when you do and turn the amplifier on- check that BOTh internal LEDs are on. that would establish that at least to a point you have the power going to both channels. There is no standard published troubleshooting method so first things first - before you get to unscrewing and removing the board to check for cold solder joints or checking for shorts or pressing and squeezing, first vicula inspection that at least you have the voltages in check the internal LEDs. They SHOULD be on, even if you have removed the OpAmp from the socket. In fact witht he AMPunplugged from Power, you could remove the OpAmp, and the 2 LEDs should be on. if they are on, then you can start looking for other things.
> 
> I think earlier in this thread -and i don;t know the post there was a diagram with voltages that can be checked.  Do You have at least a universl meter? they are not expensive and are necessary for any kind of troubleshooting.
> 
> Also - be mindful that the primary of the transfomer is at Grid (High) voltage, and if the safety  case grounding is not properly done it can be lethal.   even if grounded properly, I would feel a  more comfortable with an ELCB protected power point or at least extension cable.



Thanks for the feedback. Both internal LEDs are on. I have a multi-meter, output from the voltage regulator seems fine. I can't seem to find the diagrams with voltages that you refer to. Could you please link it to me if you manage to track it down.

I guess more information I can give is that when I have the headphone plugged in at the front, 2/3 of the way in (with 2 connection touching the headphone jack), I get sound on both side of the headphone. With this setup, I change the balance to LEFT or RIGHT balance and in both case, there is still sound coming from both side of the headphone. It seems that both side of the headphone is linked to either 1 of the channel when plugged in 2/3 of the way.

Again the problem still persist that if I plugged the headphone all the way in, I only get the right channel. It seems that the last connection (the inner most one out of the 3) for the front jacks is not working properly.

Would anyone know what sort of voltages I should be expecting from the transistors? Or any other advice on how to move further?


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## penmarker

Or it could be the connectors? I have this problem if I use my TRRS earphones due to the microphone need extra terminal on the jack. Do you have a different headphone with a 1/4" termination? Are you using an adapter for mini to 1/4" jack? Does the line out only one channel happens all the time or only when you plug in a headphone?


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## vrajcevski

I am with Penmraker on this one- Considering LEDs are on - cheap phones WITHOUT a microphone would do fine to test.


----------



## noobDiyAudio

penmarker said:


> Or it could be the connectors? I have this problem if I use my TRRS earphones due to the microphone need extra terminal on the jack. Do you have a different headphone with a 1/4" termination? Are you using an adapter for mini to 1/4" jack? Does the line out only one channel happens all the time or only when you plug in a headphone?





vrajcevski said:


> I am with Penmraker on this one- Considering LEDs are on - cheap phones WITHOUT a microphone would do fine to test.



I have done the test with cheap phones WITHOUT a microphone. I still only get the RIGHT channel on the front head phone jack and only the LEFT from the pre-amp output at the back (without anything plugged in at the front). I suspect that the different in right and left from the front to the back is just me connecting the RCA at the back incorrect.


----------



## vrajcevski

Ok,  So I Don;t know how to link directly to a post - but post 389 by Flukell has the voltages as measured on a Lehman amplifier with the diagram for one channel. I'd say if you also measure those voltages on the working channel you will have direct reference from you r version of the board as well as component. but they are a good reference and start. at least it will point you to which area to focus on. 

See if this link works well: 

https://www.head-fi.org/threads/the...ehmann-black-cube-linear-clone.501046/page-26

If not you will have to search for Post 389


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## noobDiyAudio

vrajcevski said:


> Ok,  So I Don;t know how to link directly to a post - but post 389 by Flukell has the voltages as measured on a Lehman amplifier with the diagram for one channel. I'd say if you also measure those voltages on the working channel you will have direct reference from you r version of the board as well as component. but they are a good reference and start. at least it will point you to which area to focus on.
> 
> See if this link works well:
> 
> ...



Thank you for finding the post. I just checked and all the voltages is ok.


----------



## mikaelmark

noobDiyAudio said:


> Thank you for finding the post. I just checked and all the voltages is ok.


As I already stated in my earlier post, I have experienced problem with my 6,35 mm socket - and the solution was to carefully bend the three connectors down with no headphone jack inserted.

To verify this is case also for you, please try to cut the cable on a old/damaged headphones or use a upgrade cable with no headphones to it.

Insert the jack into the amp´s socket, and with power turned OFF, open the enclosures lid and measure each at a time of the three connectors at the socket and the other end of the cable. You should have no more than a few Ohms. With the probes still left, gently push the jack in all directions and see if the resistans are changing. Repeat this for all three connectors. As you are aware your right channel are working fine, you can use that as a guideline (right channel using the middle connector and the inner (tip at the jack) are for the left channel and the connector closest to the inserting hole/nearest eclosure are ground).

If the inner connector measure different to the other, then you can try to do like me and carefully push it gently downwards.


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## noobDiyAudio

mikaelmark said:


> As I already stated in my earlier post, I have experienced problem with my 6,35 mm socket - and the solution was to carefully bend the three connectors down with no headphone jack inserted.
> 
> To verify this is case also for you, please try to cut the cable on a old/damaged headphones or use a upgrade cable with no headphones to it.
> 
> ...



Thank you for the instruction. Just checked the connector and they both read the same resistance.


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## nanchangbob

Using a test tone and oscilloscope would of course be nice, but since you probably don't have an o-scope you can select AC on your DVM and place the ground lead on the ground pin "  of the 6.35 headphone jack. Play a test tone and then 
place the red lead on left and then the right channel pins. You will read an AC voltage when playing the tone, both channels should be almost equal. If you have voltage on the input side of the socket when the headphones are plugged in
and nothing on channel of  output side of the 6.35mm socket your problem is with the socket. If you don't have an AC voltage on either the input or output side of socket on one channel you issue is before the output socket.

I don't have one of these jacks but if memory serves me correctly I believe the ground is the pin farthest from the front panel.  "verify"  These jack's are switched, so when nothing is plugged in you will not read continuity across the pins when you plug in a jack you will read close to zero ohms across the jack.      "no power applied of course".


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## vrajcevski

Do you have a spare Op Amptoswap? even ne 5532 would do to test. Ultimately any of the ones mentioned Dual OpAmps will be OK to test. cold solder could also be the issueso that one is probably best done to refresh all solder joints instead fo trying to figure out which one is bad. also - we have not really looked at the input signal coming through ? so check if any of the wires from the input actually connect to the board.  

We know you don;t get output, but not sure if you have looked if you get input at all. if you for example- as the previous poster mentioned- runa a 2 channel 50 Hz test tone, any digital meter will be able to at least show a value on the AC range.


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## noobDiyAudio

So I did more digging and replaced the input capacitor for the side that is not working, the sound did not work but at least the AC voltage measured at the input and output of the opamp for that side is no longer 0.  I also replaced the capacitor near the OPAMP for the channel that's faulty. Still no luck on getting both channel to work.

Please see the attached image.

It seems that the working side has a voltage (AC) of 0.492V for both input and output channel at 0 gain. While the non working side has 0.014V at 0 gain. It seems like something is restricting the voltage going into the OPAMP. I check the circuit diagram on the first page of this thread and the only thing that is before the OPAMP are the capacitors (which I have replaced) and the poteniometer (which I desoldered and check externally).

To go further, I have also checked the DC voltages of the transistors and they are all the same as each other (since 1 channel works the transistor for the faulty channel should show different values). 

Anyone got any ideas on what's going on. I'm stuck on what to do next.


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## precsmo (Jan 5, 2018)

ddepo by dfewo precsaseomo


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## vrajcevski

noobDiyAudio said:


> So I did more digging and replaced the input capacitor for the side that is not working, the sound did not work but at least the AC voltage measured at the input and output of the opamp for that side is no longer 0.  I also replaced the capacitor near the OPAMP for the channel that's faulty. Still no luck on getting both channel to work.
> 
> Please see the attached image.
> 
> ...


Swapping components is not the best way forward- you say you swapped the capacitor at the input on the non working channel . Do you get 0.492 V AC after it? just before the ALPS POT or not ? 

My suggestion would be to remove the opamp from the socket. and then measure if you are getting the same voltage  on the inputs of each half. If you follow the diagram - once the Op Amp is removed, you should have nearly identical AC voltage to ground on the sockets for Pin 3 and pin 5.  If you don;t then the only options would be shorted or flaky capacitors connected between the input pins and ground OR some kind of short to ground from the socket itself. - Or  dead channel on the chip.  

With 0DB setting, the OpAmp has amplification of 1 - ( o Db) which means the input voltage should be the same as the output voltage on the opamp - which you have on the working channel. on the non Working channel   the voltages are very small so - it is possible that the number you have is within the margin of error of the voltmeter - but they are essentially 0 ( 14 mV is all but zero).


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## noobDiyAudio

vrajcevski said:


> Swapping components is not the best way forward- you say you swapped the capacitor at the input on the non working channel . Do you get 0.492 V AC after it? just before the ALPS POT or not ?
> 
> My suggestion would be to remove the opamp from the socket. and then measure if you are getting the same voltage  on the inputs of each half. If you follow the diagram - once the Op Amp is removed, you should have nearly identical AC voltage to ground on the sockets for Pin 3 and pin 5.  If you don;t then the only options would be shorted or flaky capacitors connected between the input pins and ground OR some kind of short to ground from the socket itself. - Or  dead channel on the chip.
> 
> With 0DB setting, the OpAmp has amplification of 1 - ( o Db) which means the input voltage should be the same as the output voltage on the opamp - which you have on the working channel. on the non Working channel   the voltages are very small so - it is possible that the number you have is within the margin of error of the voltmeter - but they are essentially 0 ( 14 mV is all but zero).



Hi so I took out the OpAmp and the input voltage I got on Pin 5 is 0.495 V (AC) while Pin 3 is 0.033 V (AC). I checked for short circuit and even replaced both the caps near the OpAmp, still same result. I did noticed something strange though, if I plugged in the amp, leave it on for a few minute then turn it off, when I check the continuity between the Right side and the middle ground (at the input socket) my multimeter buzz not beep but buzz. Really odd, the same behavior can be exhibit when I check between ground and the resistor next to the right gain switch (from the photo I previously attached). When I check continuity elsewhere the multimeter beeps as normal, only when I do the steps mentioned will it buzz.


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## vrajcevski

ok, so could be anything - related to cold solder - I would simply resolder all the spots in the path from the input to the opamp - i don;t think you have a [roblem further back, but may be worth checking anyway. it sounds like a cold solder that is intermitently connecting, and it sounds like the 0.033vAC you are getting is actually caused by a ground loop, rather than any input coming throough.  

Also , when you take the board out, check for anything at the bottom touching the case and shorting. While you are at it, just check all the traces and solder points for shorts. the fact that your input to the OpAmp is so low simply limits the space to look for. there are probably about 6- 7 solder points to check.


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## nanchangbob

OK, I think you need to reset and look at the more analytically. If your going to start messing with electronics you should really do some reading or take a course as it can hurt or even kill you.

That said, look at what you have, one channel not operational.  If you have one channel working you can assume that your voltages on your op-amp are not your problem. Op-amps have positive and negative supplies and since you are using a dual op-amp than your supplies are good since one channel is working.   As I mentioned before you can download a test tone and check the output using a DVM on AC this will only let you know that the signal is reaching your jack.  Here is a place you can download the test tones. http://www.kicker.com/test-tones

If you are going to troubleshoot this thing you really need an o-scope, I have a cheap Hantek that I use sometimes and I have uploaded a few pictures of the signals. 

First is the input and output of the op-amp, I normally keep the switches both down for 0db gain, but I switched one up so that you could see the signal gain. I clipped the channel one lead on the 10K resistor going into the op-amp and the channel two probe was connected to the 47R on the output. Signal-in "good" signal out with gain = good op-amp.  You would then jump to the output if both channels check good. Checking AC voltage around the op-amp will show you little to nothing. Remember an op-amp amplifies the difference of the inputs, If the chips have the +VCC and -VCC it will amplify the difference of the inputs.

If you have actually downloaded and played the test tones and check at the output jack and one channel has readable voltage and one doesn't the first place to start if your not willing or able to get an o-scope replace the op-amp. You can buy a OPA2134 from eBay for $3.99 including shipping. Do not do any soldering and don't pull your amp apart. When you place the op-amp in the socket be careful with the pins. I hold it in my fingers and bend the pins on a desk to make sure the align properly with the holes. Also make sure the notch on the top of the op-amp is aligned correctly. Good luck!


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## noobDiyAudio

vrajcevski said:


> ok, so could be anything - related to cold solder - I would simply resolder all the spots in the path from the input to the opamp - i don;t think you have a [roblem further back, but may be worth checking anyway. it sounds like a cold solder that is intermitently connecting, and it sounds like the 0.033vAC you are getting is actually caused by a ground loop, rather than any input coming throough.
> 
> Also , when you take the board out, check for anything at the bottom touching the case and shorting. While you are at it, just check all the traces and solder points for shorts. the fact that your input to the OpAmp is so low simply limits the space to look for. there are probably about 6- 7 solder points to check.



Thanks for the advice I have since cleaned all the solder joints and resoldered all the points on the input side of both channels (just to be sure)



nanchangbob said:


> OK, I think you need to reset and look at the more analytically. If your going to start messing with electronics you should really do some reading or take a course as it can hurt or even kill you.
> 
> That said, look at what you have, one channel not operational.  If you have one channel working you can assume that your voltages on your op-amp are not your problem. Op-amps have positive and negative supplies and since you are using a dual op-amp than your supplies are good since one channel is working.   As I mentioned before you can download a test tone and check the output using a DVM on AC this will only let you know that the signal is reaching your jack.  Here is a place you can download the test tones. http://www.kicker.com/test-tones
> 
> ...



Hi thanks for the concern, I am experienced with electronics. I have spare OPAMPs, unfortunately I do not have the o-scope. I have taken the OPAMP out of the circuit and the problem seem to be from the input. There's not much to the input circuit, but after triple checking everything , including for shorts the problem still persists. This is a really odd issue.


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## noobDiyAudio

Thanks for those who have assisted me during this issue. 

Attached are more pictures of the voltage measured at the specified given test conditions, I measured both the working Right Channel and the non-working Left Channel.

I have checked the continuity of the circuit and for shorts to ground. I am really stumped as there are not much components between the signal and the input to the OPAMP and I have checked all the components (even replacing some of them). I also replaced the terminal at the input end, it's really odd how at the point where the signal enters the circuit (the terminal) the voltage is already incorrect. I also tried using different input jacks and cables and the problem is still there.


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## nanchangbob

What is the resistance reading to ground from R201 and R205? 

What is the resistance reading from both sides of the input capacitor to pin 5 of the op-amp?


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## noobDiyAudio

nanchangbob said:


> What is the resistance reading to ground from R201 and R205?
> 
> What is the resistance reading from both sides of the input capacitor to pin 5 of the op-amp?



The resistance reading from R201 and R205 to ground are:
R201 and R205 to ground = 48.7k (pot end)
R201 and R205 to ground = 58.3k (input end pin 3 and 5)
input caps to pin 3 and 5 = 58.3k


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## nanchangbob

To make sure there is no confusion!

1.  Op-amp is in placed and not pulled.
2.  Measure pin 7 to ground that is R205 according to the schematic you provided.
3.  Measure pin 3 to ground that is R201.
4. Put one tip of your dvm tip on the RCA input center pin and put the other dvm prob tip on pin 3 of your op-amp. Just a simple continuity test. test resistance. Mine measure around 26K ohms, it will depend on the capacitor, but it should be something near that value.
5. Repeat the above steps on your right channel.  You should then be able to determine which side of the op-amp you are having a problem. You mentioned you have a lot of op-amps? Did you try replacing the one in your unit with another dual op-amp?

With my op-amp in place I read over 13.5 M ohms on pin's 1 & 7 of my op-amp.


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## vrajcevski

asmuch as I can agree with what you said, the whole thread started as support to somebody who has no or minimal knowledge, and minimal tools. AND no titme or possibly inclination to go take a course and buy tools.


 the topology of the amplifier is quite simple.

if you remove the OpAmp, you basicaly have the input signal terminating on the Opamp socket input pins. this then goes Nowhere UNLESS the OpAmp is in the socket and working .

if you feed the same signal on each channel ( rca) you should expect to get the same value on each channel input pin on the socket - and if you don;t then you have a problem in the path to to  OpAmp socket input pin.

if you do get the same vaolue  , then it is likely that there is a dead opamp channel.

the whole discussion has gone the way it has simply because of the assumption of minimal knowledge of electronics and no measurement instruments apart from universal meter - tape and gum so to speak. I still think eliminating cold solder or even something as trivial as short under the board across the positive and negative inputs on one channel is simple enough to do .

But yes, a course and instruments would be great if the interest is there - otherwise it will be much cheaper to simply go to the seller and get a replacement or refund -with the risk that the same problem may happen again.


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## vrajcevski

based on the No OPamp measurements, it looks like you  get o.o3 at the very RCA- I assume you have checked for no shorts on the RCA itself?  if you just sum the voltages on the path from the very input to the input pins, you get almost no voltage drops, meaning minimlal current flow .   

What is the input AC voltage of the signal before  you plug the RCA cable into the input? I assume it should be 0.485V  or close? If that is true  then the only thing to explain drop to 0.031v  there is a short to ground somewhere. to prove- or disprove - what is the resistance between Signal and ground  you get on the RCA socket itself? for DC it should be open circuits after the input capacitors and c318 charge completely-  this would be no signal and no power on measurement.


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## noobDiyAudio

vrajcevski said:


> asmuch as I can agree with what you said, the whole thread started as support to somebody who has no or minimal knowledge, and minimal tools. AND no titme or possibly inclination to go take a course and buy tools.
> 
> 
> the topology of the amplifier is quite simple.
> ...



Hi thanks for the help, I've asked the seller to send me a replacement.


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## requal (May 17, 2018)

noobDiyAudio said:


> Hi thanks for the help, I've asked the seller to send me a replacement.


Just want to say: the same problem on this board  Anyone had resolved it?

Edit: I found problem. It was broken transistor in my case.


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## mikaelmark

If connecting a headphone amp. to a home cinema receivers PRE Out or AV Out, must the receiver be powered on, or will the headphone amp. get the signal also if the receiver are turned off?

And what´s the difference between PRE Out and AV Out? Should´nt both be low voltage, suited for example an external amp? My receivers manual, says the PRE Out will have the same signal as from the speaker cables and AV Out will only output from analog in -sources.


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## mikaelmark

I have now replaced the OpAmp from OPA627 to Burson V6 (discrete) for two units, and for one (battery driven), it working fine.

But for the other unit, after a few seconds after first turn on, it was a quiet "Pofff", followed by a smell of burned electronics! And now only the two LED´s near the OpAmp will light - the one in the front beside the headphone jack is off and also the regulator´s LM317/337 will not be heated up.

I can not see any damaged capacitor or anything else, so maybe it´s the new Burson OpAmp exploded!? Do someone have any idea what could have happened?


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## davveswe

do you have any good tweak to remove dc offset? some opamps in the amp has high dc offset, especially with 10x gain.


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## davveswe

Where can i get opamp bias adapters?


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## mikaelmark

You can buy them in your "local" electrical equipment store or at eBay/Amazon for example. They will be quite cheap, and I advise you to look for gold plated one´s.

But, if you´re a bit handy, you can do like me and solder the two resistors directly on the secondary side of the PCB (down side), between pin 1, 4, and 7 at the OpAmp without using any extra socket/adapter.

Note that I removed those resistor´s, when swapping for Burson V6, as there may be risk for everheating otherwise.


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## UncleGrandpa

Hi there!
I have been using the Lovely Cube for 2 months now, and I'm planning to upgrade its opamp to SS3602. May I ask if there is any steps I need to take apart from replacing the OPA2134 with the SS3602 itself? I saw some people must did something like "class-A bias". 
Also, in you guys' opinion, it is worth to upgrade the 2134 to the SS3602 and what are the changes? 

Thank you guys very much!


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## penmarker

Every circuit responds differently to opamp changes, you'll need to roll them yourself to listen to what's best for both you and the amp.

No special steps to replace the opamp. Just turn off the unit and unplug, leave for a few minutes so the power caps discharge, and swap out the opamp.
The class A biasing requires another opamp socket and soldering some resistors. The guide is the same across most opamps but I don't recommend it for fear of overheating.


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## UncleGrandpa

penmarker said:


> Every circuit responds differently to opamp changes, you'll need to roll them yourself to listen to what's best for both you and the amp.
> 
> No special steps to replace the opamp. Just turn off the unit and unplug, leave for a few minutes so the power caps discharge, and swap out the opamp.
> The class A biasing requires another opamp socket and soldering some resistors. The guide is the same across most opamps but I don't recommend it for fear of overheating.


I'm using the original lovely cube which was bought from Alicemagicbox. If possible, do you think it is necessary to upgrade the opamp? Thanks!


----------



## penmarker

UncleGrandpa said:


> I'm using the original lovely cube which was bought from Alicemagicbox. If possible, do you think it is necessary to upgrade the opamp? Thanks!


I wouldn't make it a priority. With my V5 the improvement is subtle and I can't really remember how the stock 2134 or upgraded 4562NA sound like. 
The great thing is opamps (except those audiophile marketed ones) are cheap, and you can just buy a bunch and roll through them.


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## UncleGrandpa

penmarker said:


> I wouldn't make it a priority. With my V5 the improvement is subtle and I can't really remember how the stock 2134 or upgraded 4562NA sound like.
> The great thing is opamps (except those audiophile marketed ones) are cheap, and you can just buy a bunch and roll through them.


The SS3602 is like 70$ so it is not so cheap. I read a lot on this thread and found some members said that the 2134 was trash? So now I'm pretty confused when you say the improvements are subtle with such a good opamp like the V5.


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## penmarker

I upgraded from the 2134 to the 4562, and only later to V5. I haven't compared the V5 to the 2134 and I don't think I can find the 2134 anymore to compare.

The 2134 is certainly not trash, they sound okay as a stock opamp but there are better opamps out there.


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## UncleGrandpa

penmarker said:


> I upgraded from the 2134 to the 4562, and only later to V5. I haven't compared the V5 to the 2134 and I don't think I can find the 2134 anymore to compare.
> 
> The 2134 is certainly not trash, they sound okay as a stock opamp but there are better opamps out there.


Yeah of course there are better opamps, just that I don't know if it is worth to upgrade to them, because the best opamp costs quite a lot


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## penmarker

UncleGrandpa said:


> Yeah of course there are better opamps, just that I don't know if it is worth to upgrade to them, because the best opamp costs quite a lot


Honestly after you get to a certain price or performance point, the differences between parts or component or product start to shrink. I'd recommend you to go for it and get the 3602. Maybe in the future you get another amp with swappable opamp and you can reuse it if you want to. But if you want an objective experience between that vs 2134 you'll have to wait for someone who had tried to chime in. Or probably look for the opamp thread in the DIY section (IIRC there's one there) and read through their impressions.


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## KonstantinN (Sep 25, 2018)

chetlanin said:


> The lazy way to correct for voltage offset independently in L or R channel.(there are other ways, of course!)
> 
> (In my case the offset was rather high in one channel, 17mV, while very acceptable in the other. A little trying and failing, and I ended up with less than 1mV offset by reducing the resistance in (what I call) R3 in the drawing to ca. 1.4k by  (from 1.5k) by adding an Rx=18k in parallel. The Idle current was accordingly increased by less than 2mA (of 57mA originally), a totally insignificant change IMO. I don't know if this could be of interest to any of you. You can see the added resistor in the photo).
> 
> ...


This is also my first post here even though i am a long time lurker.
Following the direction of chetlanin and bla-bla’s comments, i zeroed DC offset of my LC output by soldering 4 variable 50k resitors in parallel to the 1.5k resistors (R25, R28,R29,R32) on the schematic.









A bit of nipples turning - hooray! 0mV DC in both channels!

And a note about Muses8920 opamp for the Lovely Cube - it sounds great! With good recordings - better than 2111 to my taste for width and depth of the sound stage and instruments separation and positioning. Unfortunately it comes at the cost of less engaging vocal and emphasizing of bad recordings imperfections. Had anyone tried Muses01 in the Cube ABing with 8920?


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## penmarker

What you can try is getting some substantial heatsinks for the output devices and put in a Burson V5 or V6.

The only reason for the heatsink suggestion is because the Bursons don't like high temps. My V5 works fine, however some people reported their opamps burnt in class A designs. The spec also rates the operational temp only up to 55 degrees C if im not mistaken.


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## francisdemarte

Amazed and glad to see this thread is still active 8 years after it was started  Rock on!


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## Cidious (Dec 16, 2018)

I'm still rocking my Lehman clone. As you can see it underwent a lot of customisations and tweaks through time. But this is practically how I ran it for over a year. Sometimes rolling some opamps.. Got a Burson V6 Vivid incoming. Look back in this thread for the customisations that I made and why.

As far as I can remember

60VA transformer (biggest that could fit. from 40VA to 60VA)
Mundorf 4700uf PSU caps
Panasonic FM PSU caps
ELNA Silmic II at the opamps
Resistors are audio grade ones in signal path.. need to look up what types.. blue and red hahaha
Zener PSU mod
Some bigger electrolyte caps at the PSU
Matched all voltage regulators and resistors. everything PERFECTLY matched
Clarity bladiebla caps at the signal input positions
Black wima caps in signal path
and for Opamp decoupling I used these small black drops which I forgot the name of.. Some luxury stuff.. I rolled quite some caps in and out and they sounded best.



 



 

I mainly run the Lehman with my Mad Dogs and my  (heavily) modified DT770 (has nothing DT770 in it anymore. 45MM Tesla drivers and similar dampening to the DT1770 with some tweaks here and there. Lovely set of cans. Got a set of MrSpeakers Aeon closed incoming. So I took another look over the amp to see if everything is still performing as I want.



 

 

Current Setup
Laptop -> USB -> UFEEL USB004 (signal purifier) -> QED Custom USB cable -> Topping DX3 Pro + Linear PSU -> QED signal lines -> Lehman BCL clone headphone amp + 2xOPA111VM or 2xOPA627BM + UFEEL MK902MKIII dip8 adapter -> Mad Dogs or DT770 Tesla mod cans

Replacing the opa with Burson V6, adding MrSpeakers AEON closed cans, Maybe trying Topping D50 DAC since they are so darn cheap in China. €140 with 11.11, 12.12 or 1.1 discount haha. That's worth to try.


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## Cidious

Got me a Burson v6. Lord what fun! I'd say 20% audio performance improvement over the dual single opa627bm or dual single op111vm. 
More refined and defined. Less noise and everything just sounds more confident and controlled. Bass is tight and thick. Highs are defined but not harsh. Mid a little laid back on the Vivid. But it pairs well with the dual AKM 4493 DAC I'm running with. 

I don't think there is much more I can tweak out of the Lehman. This was another great upgrade. Worth it. Total cost of my unit might not be very budget friendly anymore but certainly top notch.


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## mikaelmark

What will be the result, if using a lower value for the DC coupling cap´s, for example: 1uF instead of 1,5 – 1,8uF?

I found information about how to calculate/determine the value, and if decreasing/lowering the value, it may generate more distortion and that the headphone impedance may change the minimal capacitance value needed. It also say´s a higher capacitance value is ofter preferred.

So, should 1uF be enough for this LBC-amp? And what will the result be versus using original value?

https://www.eetimes.com/document.asp?doc_id=1274884


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## KonstantinN

mikaelmark said:


> What will be the result, if using a lower value for the DC coupling cap´s, for example: 1uF instead of 1,5 – 1,8uF?


f3dB = 1/(2*pi*R*C)
Reducing the blocking capacitance value you decrease amount of low-frequency signals that will pass it. For LC 1uF is still fine, It means that 3Hz input signals will be decreased by 30%. The lower the frequency of the signal, the more signals will be decreased.


----------



## mikaelmark (Jan 13, 2019)

KonstantinN said:


> f3dB = 1/(2*pi*R*C)
> Reducing the blocking capacitance value you decrease amount of low-frequency signals that will pass it. For LC 1uF is still fine, It means that 3Hz input signals will be decreased by 30%. The lower the frequency of the signal, the more signals will be decreased.



Ok, so you do´nt think it will reduce an hearable amount within the hearable frequency range over 20Hz? How many dB lower will it go/block?

And are there any pros. if choosing lower value and any cons. if choosing very high value, let´s say more than 2uF?


----------



## Cidious

Popped in a Burson V6 vivid.. Felt like the sound quality improved by about 15 over OPA627BM and OPA111VM.. Couldn't believe my ears.. Then a bit later I got a Sparkoslabs SS3602 discrete opamp.. and another 5-10% improvement over the Burson V6 to my ears... and then I rolled back to dual OPA111VM and OPA627BM to verify... and they can't come close... 
The Burson costs about €65 and the Sparkoslabs €80... but... I'd say WORTH IT


----------



## lawrence2357 (Feb 14, 2019)

Hey all I just bought one of these used and I'm very impressed. Assuming it came stock, what opamps should I try? I'm using HD560, HD580 and HD650. (I'm assuming there's no point in trying to drive my HE6!) For the 560s I'd like a little taming of the highs, the 650s already sound good so just a bit more "quality" if that's possible. The 580s are as you'd expect in the middle so something suited to them would be nice too but I could probably live with one or the other. I don't want to do any other mods, recent posts refer to extra heat sinking for Burson opamps so I'd rather avoid that.

Oh I'm also thinking of using it as a preamp, are the opamps in circuit when used like that?

I should also start a new thread for my other amp I just bought, an Iota Audio Reference, wow that's something else. Virtually nothing on the web just a passing reference that they are available.


----------



## Cidious

Opamps that I found very suitable for most of my headphones were opa2111vm (or dual 111vm) opa627bm Burson V6 (discrete) and Sparkos SS3602 (also discrete) 

The Burson V6 is a very good opamp for it's price. And you can have a vivid and a classic to roll for different music styles / headphones. But obviously it won't come cheap. Vivid being more clear and analytical and defined. Classic being more musically pleasing and organic but less detailed. Both of them very good opamps and bring clarity and control.

A step above that (also quite a bit more expensive) is the Sparkos SS3602. It's practically the end game. Best of both worlds of the Burson V6 versions. Without any significant weak sides. Very well balanced, neutral and great detail and control. Sounds effortless. 

I'm running Sparkos SS3602 now but I'd be happy to use the Burson V6 too if I didn't have the Sparkos laying around. As for the aforementioned IC opamps.. they are better than most other IC opamps... But in terms of clarity they just can't compete with the discrete ones.. I'd never go back to IC for the headphone amp. 

I hope it helps. All depeneding on budget I guess.


----------



## lawrence2357

Thanks for that Cidious, the previous owner is selling me his collection which are:

"the original stock chinese op2134 which was a bit nasty, a proper Texas Instruments 2134PA, and pairs of op 602AP, 637bp and 797anz which I think need that adapter which is also there."

Do you know if any of these are any good? I'll keep an eye out for some second hand discrete ones.


----------



## zxzxzx207

I was just wondering. Does any one have a high resolution picture of the sticker at the bottom of the amp? Mine didn't come with one and I want to print one out


----------



## Cidious

lawrence2357 said:


> Thanks for that Cidious, the previous owner is selling me his collection which are:
> 
> "the original stock chinese op2134 which was a bit nasty, a proper Texas Instruments 2134PA, and pairs of op 602AP, 637bp and 797anz which I think need that adapter which is also there."
> 
> Do you know if any of these are any good? I'll keep an eye out for some second hand discrete ones.



Uhm I didn't really personally like any of those on headphones. 797 does well in my DAC's IV stage but not so well in my headphone amp. 637bp I haven't tried but read and heard 627bp is better. 602AP I don't know. and original 2134AP is ok but nothing to write home about. I would look for 2x627BP or 2(x)111VM or 2604AP. and if you can afford maybe one of the Burson V6 variants. they are about 20-25% better than the best IC opamp that i've tried. It really lifts the veil of things and makes the sound more effortless somehow.


----------



## zxzxzx207

In case someone needs it in the future, I remade the label at the bottom of the case.


----------



## mikaelmark

I intend to replace the voltage regulators LM317 and LM337 with Sparkos discrete SS1117-15 and SS7915, as the Lovely Cube will run at +-15 VDC.

Has someone any experience about those voltage regs?

https://sparkoslabs.com/discrete-voltage-regulators/


----------



## mikaelmark

zxzxzx207 said:


> In case someone needs it in the future, I remade the label at the bottom of the case.


Also have in mind that if only DIP Switch no. 2 is on, then the Gain will be 18dB.

I don´t know why this are only being illustrated for some labels/pictures!


----------



## mikaelmark

I just made some picture modding, to include the 18dB Gain:


----------



## zxzxzx207

Ah yes I noticed the 18dB one as well, never included it as I just preferred even numbers i guess haha. Btw if you just started making the amp, I silk-screened out my label on aluminium 
	

	
	
		
		

		
		
	


	




 If you're interested you can have one for the cost of shipping as I had to print quite a few.


----------



## zxzxzx207




----------



## mikaelmark (Apr 14, 2019)

Sparko told me the 100 Ohm resistor´s should be removed and that 1K1 resistor´s should be shorted when installing the discrete voltage reg´r SS1117-15 and SS7915. So the Zener mod (see earlier post´s in this thread) should will not actual here.

Also, a Mica Wafer should be used between this voltage reg. and heat sink: https://www.elfa.se/Web/Downloads/-1/_7/kjE-1_7.pdf


----------



## mikaelmark

The use of Mica Wafer for insulation between a voltage regulator´s tab and heat sink, seem´s to be important, as the tab will have voltage on it and are NOT grounded. I assume this is only for safety, if the heat sink will be in touch with the grounded enclosure (I have mistakenly done this fault for the LM337 without the mica, and was heard a loud BANG, then it was dead - but after a while it worked but may get some noise to the sound).

Also, when using Mica Wafer´s, Thermal Compound should be applied at both side´s of the Mica, due to the risk of overheating otherwise. And don´t forget to isolate the hole at the tab if using metal screw to the heat sink.

There are also recommandation´s about using Mica insulator´s for transistor´s, so maybe the BD139/140 heatsink´s should have Mica inslutator´s, altough the tab for the heat sink´s are grounded!? Any thought´s about this?

https://books.google.se/books?id=wU...QAQ#v=onepage&q=mica thermal compound&f=false


----------



## zxzxzx207

If you want to make your life easier, just use silicon heat transfer pads. cut to size and apply. They are not electrically conductive. I've used it in the past in a few of my builds. When using thermal paste make sure to use non conductive and non capacitance paste.


----------



## Dukei

I agree with zxzxzx207, as it still considered low voltage any type of insulation is ok to insulate with. I'd go with the most common and cheapest heatpad


----------



## mikaelmark

zxzxzx207 said:


> If you want to make your life easier, just use silicon heat transfer pads. cut to size and apply. They are not electrically conductive. I've used it in the past in a few of my builds. When using thermal paste make sure to use non conductive and non capacitance paste.


I will Arctic MX-2 thermal paste for both side´s of the insulation.

But, should the transistor´s BD139 and BD140 (SOT-32) also be insulated to it´s heat sink?

There are some recommendation´s about grounding the heat sink´s (supposedly due to eliminating EFI/EMI that may generate noise otherwise), and I understand that voltage regulator´s LM317 and LM337 must be insulated to the heat sink because the tab are not connected to ground. But this is not true for the transistor´s.

http://www.learningelectronics.net/circuits/high-power-headphone-amplifier-using.html

I hav´nt used any insulation so far, but maybe there should be some advantage´s?

Any thoughts or recommendation´s about this?


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## mikaelmark (Apr 20, 2019)

zxzxzx207 said:


> If you want to make your life easier, just use silicon heat transfer pads. cut to size and apply. They are not electrically conductive. I've used it in the past in a few of my builds. When using thermal paste make sure to use non conductive and non capacitance paste.


Are below what you referring to (0,3 mm Sil Rubber, Thermal Gap Pad):

https://www.elfa.se/Web/Downloads/46/02/07564602.pdf

It seem´s to be quite similar to Mica wafer; Dielectric strenght: 5 versus 6 kV mm and thermal resistance: 0,4 K/W. And if using the Sil-pad, I assume thermal paste should be used, however!?

And for insluting the mounting M3 screw for the heat sink, this polyamide insulator should be fine: https://www.elfa.se/Web/Downloads/-2/_5/ktE-2_5.pdf


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## zxzxzx207

https://www.google.com/amp/s/www.westfloridacomponents.com/wfc/amp/product/G321APF03.html

They make them precut too. With the pads no thermal paste is needed. The one I'm using has to be cut to size but it's a lot cheaper.


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## Dukei

If the the BD139 and BD140 have metal tab on the backside and they share the heatsink togheter, then they should be insulated. 
Don't forget to isolate the screw aswell, (if you are using metal screws).


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## zxzxzx207 (Apr 20, 2019)

https://imgur.com/a/9wDR22H

So this is my build, 99% complete, just waiting for an ITO top to come and I'm done

For LT317 and LT337 its mica + nylon washer and thermal paste
BD139-16 and BD140-16 is just thermal grizzly kryonaut.


----------



## vintageaxeman

zxzxzx207 said:


> https://imgur.com/a/9wDR22H
> 
> So this is my build, 99% complete, just waiting for an ITO top to come and I'm done
> 
> ...



What is an ITO top please?


----------



## zxzxzx207

Right now the top is acrylic. ITO glass is conductive glass that I will use to replace the acrylic. Help reduce interference not that there is any now tbh but just smth nice to have.


----------



## vintageaxeman

I would like to use that on the top of my modded cd player. Is it easy to obtain? Where are you getting yours from please?


----------



## zxzxzx207

Not that easy to find, some science equipment suppliers can sell it. I had to go trough some of my contacts from work as they normally don't do single orders. For reference the ITO top for this was 50USD. It is not cheap especially for one off pieces.


----------



## wrexel

Hi I have a Lovely Cube which has been gathering dust as I haven't been listening to CDs for some time and was thinking of connecting a streaming source to it. Would it make sense to connect a USB DAC to it and use my phone to stream music to it and if so how would I connect into the line ins for the Lovely Cube? I would be using a HD600 mostly for listening. Thanks in advance!


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## KonstantinN (May 2, 2019)

Have tried negative feedback mod for the amp. It is a game changer for low impedance headphones! My 16 ohm 70mm driver cans have moved to a higher league  Dynamic range and transparency have been improved dramatically. And the mod is very easy to implement - you need to desolder one end (the one that is closer to the back side of the amp) of 4.7k resistors near the opamp and connect it to the middle point of the output 10 ohm resistors.
Original blog post: https://blogs.yahoo.co.jp/be_kow/53647233.html







Author implements the mod on back side of the board, while it can be done of front side also:





Happy modding!
Native OPA2134 sounds very detailed in such configuration. OPA2604 adds more bass  Other opamps may require 10pF capacitors across 4.7k resistor or setting the gain to 0db.


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## mikaelmark

This week I finally finished my LBC -amp, as I replaced the standard voltage regulators LM317 and LM337 for Sparkos discrete 7915 and 1117-15 (+- 15 Volt DC). I used Silocon pads between the regs tabs and the DIY heatsinks, made of a strip of aluminium connected to the enclosure, using nylon M3 screw.

https://sparkoslabs.com/discrete-voltage-regulators/

Paired with Burson V6 Vivid, Mundorf 10.000uF M-Lytic, Audyn True Copper (huge size) bypassed with Russian FT-1 Teflon, Holco H4/PRP9372 1 Watt resistors, Polystyrenes, Elna Silmic, Panasonic FR, BYV-27, PCB with extra thick copper, OFC wiring, matched transistors BD139/140-16 and a Dale 24 step volume attenuator.

Next week I will do a comprehensive A/B-testing against Burson Fun, V6 Classic and Sparko SS3601 and promise to do a review.


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## mikaelmark (Jun 16, 2019)

Here´s a link to the review: https://www.head-fi.org/threads/bur...l&utm_source=watched_thread_reply_messagetext

Another thing; Someone suggested shorting pin 5 and 8 (Trim and NC) for single OpAmps, such as OPA134 and OPA627, for DC Offset.

Can this mod be applied for any single OpAmp, if they´re solderet to an double single to dual -socket in the LBC, also discretes? And what are the advantages?


----------



## mikaelmark

As the Power supplies cap´s C103, C104, C203 and C204 in the output stage should be 470uF as standard, and can safely be increased to 1000uF - do anyone know if it´s ok to increase them to 1500uF?

Or is that too much? Pros and cons?


----------



## KonstantinN

mikaelmark said:


> As the Power supplies cap´s C103, C104, C203 and C204 in the output stage should be 470uF as standard, and can safely be increased to 1000uF - do anyone know if it´s ok to increase them to 1500uF?
> 
> Or is that too much? Pros and cons?


The more, the better. While real improvement of the ripple is negligible after some capacity.


----------



## mikaelmark

KonstantinN said:


> The more, the better. While real improvement of the ripple is negligible after some capacity.


Thank´s for your quick reply!

Some people stetes higher values for components will generate more noise to the sound (same for faster rectifier diodes).

As I have some 1500uF Panasonic FR, I may use them for this position for my latest insanely modded LBC, with SparkoS SS3602 discrete OpAmp and Intertechnik Audyn True Copper Cap for DC coupling. But I´m a bit confused about those caps, as the manufacturer assert that due the construction of those caps, they should only be used in crossovers for spekers, and for DC coupling one should choose their MAX sibling model. But what can happen - it should not be a safety risk due to the low signal voltage and for me the sound is fine?

Any thoughts about this?


----------



## KonstantinN

mikaelmark said:


> Some people stetes higher values for components will generate more noise to the sound (same for faster rectifier diodes).


Too generic statement. My answer was about specific components (capacitors) at specific place, playing its role in specific function (Low frequency filter).



mikaelmark said:


> Intertechnik Audyn True Copper Cap for DC coupling. But I´m a bit confused about those caps,


I do not know this manufacturer and never saw a data sheet for the mentioned capacitors. Therefore - no comments from my end.


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## mikaelmark

I´ve earlier tested and reviewed the Burson V6 in the BCL, that were quite good, and a couple of months ago also SparkoS SS3601/2 - and those were truly fantastic in my BCL amp!

Now, I´m up for testing the NewClassD and soon also from Orange. This far, the NewClassD has only been fitted in a AK4399 DAC, and it seem´s very promising!

But one small thing is confusing me a bit; Lars Clausen from "Dexa", that were kind to provide me with the NewClassD discrete OpAmp, suggested me to fit some bipolar Mylar caps to each power pins as a complement to the original electrolytic 240uF in the schematic. This should favor the 20kHz and below 200Hz sound. He told me those caps should preferrably be 1nF or at least 0,33uF but 1uF are also ok! But 0,1uF and 0,47uF are not ok!

Why?? Can someone please describe this for me, as it do not seem´s logical!?

However, yesterday I soldered some 2,2uF Vishay KP1830 (all measured 2,1uF) to each V+ and V- pin to ground, totally four caps for single discretes. And to my ears, I believe the sound are now better than before.

But when I gave him the BCL schematic, he told me it seems to already having enough stabilization caps to ground.


----------



## mikaelmark

I´m testing several discrete OpAmp´s for my portable LBC (with first generation NiMh 16VDC/2Ah battery pack), all with good results. And the batteries are drained to about 7VDC, then the volume will be a lot lower and if going below the OpAmp´s working voltage, it will also be distorted. Now, I wonder about some things:

1. As the input power is directly connected to the +/-15VDC output at the voltage regulators LM317/LM337 to minimize the power draining from the battery, so also the voltage reg´s and the two big power power filter cap´s and of course also the rectifier diodes, will not be used - may the voltage reg´s draw any mAh current backwards, altough there are no draining component at this direction other than the unused power stage. Maybe it´s best to remove the whole power section (by removing the voltage reg´s or cut the PCB´s copper conductor´s for the output pin´s)?

2. Should the two big filter cap´s (with original value 4700uF) be used altough the amp is running by batteries, or will the OpAmp be satisfied without them powered in realtime directly from the batteries?

3. Can I safely remove all the three (or any of them) LED´s for the amp, to minimize the battery draining?

4. As those discrete OpAmp´s will accept 24VDC, will it be fine if raising the batteries voltage to something between 18 and 24VDC?

5. With above in mind, should the amp be better if replacing the NiMh with Lithium, such as dynamic and transient speed etc?


----------



## mikaelmark

Some people told me this LBC -amp will not have any local negative feedback from the output stage to the input, so it will have a high DC Offset and also have insane output levels and maybe also high distortion!

Any thought about this and maybe what to do about it/how it can be fixed?


----------



## mikaelmark

I just get an recommendation from SparkoS, to solder a 22pF NPO/COG film/ceramic cap in parallel with each 4K7 resistors R102 and R202 for negative feedback to ensure stability for high speed, high performance OpAmps, such as discretes (where there´s a risk for oscillation).

Those will be connected to 1 - 2 and 6 - 7 (-In/Out for each channel).

Don´t know if this mod will fix the problem with the local feedback/DC Offset, but it should not affect the sound quality as the bandwith will be around 1,5mHz.


----------



## mikaelmark

By default, this amp are having fast recovery rectifier diodes BYV27 (not the cheaper and slower "standard" 1N400x) bypassed with 0,1 uF capacitor for each diode to eliminate unwanted high voltage peakes (refer to R301 - R304 and C301 - C304 at the schematic).

But some people say those bypass cap´s should only been used for standard slow rectifier diodes, eventually also combined with a low ohm resistor in serial. If BYV27 has bypass caps, there may be a worser result as there will be a small amount of quiscent/leakage AC current.

Maybe it will be better if removing those 0,1uF bypass caps (the four square in the power supply)? Any thoughts?


----------



## mikaelmark

One week ago, I E-mailed Norbert L. about his design for the BCL Linear SE, using BYV27 with 0,1uF plastic films in parallel with each rectifier diode - but has´nt been replied from him yet.

However, I get an reply from Andrew Sparks (the guy at SparkoS Labs manufacturing discrete voltage regulators and the phenomenal SS3602 OpAmp), and he´s VERY kind and helpful and has a big technical khow-how, and he gave me this link below:

https://diyaudioheaven.wordpress.com/tutorials/power-supplies/snubbering/

So the suggestion for the LBC amp will  be to remove the four plastic film 0,1uF C301 - C304, and then solder only one capacitor (either one of those four being removed or maybe even better a NP0/C0G X7R ceramic capacitor) with one resistor at about 10Ohm in series to it (between the two incoming transformers secondary AC and before the four rectifier diodes - I suppose preferable after the two yellow temp. fuses RF1/RF2).

This Snubber mod should ensure a cleaner power stage for the LBC and combined with the voltage regulator diode mod (see earlier posts in this thread), this amp will do it´s best for your headphones!


----------



## penmarker

Mikael, is it possible to increase the class A bias current to the output devices if we mount them to larger, more substantial heatsinks?


----------



## mikaelmark

Penmark; -If you´re talking about Class A for some standard IC OpAmp, such as OPA2164, NE5532 and OPA627 by using two resistors at for example 4,7k Ohm between -neg voltage and both output, then it´s possible to decrease the resistor value to get a higher biasing. But I don´t think you should go below 3 - 4k Ohm.

Of course this will increase the power consumption for the OpAmp, but I don´t think it´s necessary to use any bigger heatsink for the voltage regulators or BD139/140-transistors (as long as you´re not going insanely low for the resistors).

But have in mind that this BIAS mod will not get be a true Class A, and will have some negative aspects - as it will be if going for a discrete OpAmp, such as SparkoS SS3602:

https://tangentsoft.net/audio/opamp-bias.html


----------



## penmarker

No I am not referring to the opamp biasing but the BD139/140.

I'm asking because while building the SuSy DynaHi, the heatsink fins regularly get over 50°C. Looking at how small the heatsinks are on the BD139/140, I feel like the biasing could be increased with substantial heatsinking.


----------



## mikaelmark

Don´t be worried, the BD´s can go as high as 150 degrees Celsius (junction temperature), and works best at about 75 C. Therefore, you will get the best sound after the amp has reached it´s optimum working temperature, after about 15 - 60 min. This is even more important if using tubes.

I´ve often experenced my gear will get quit hot after about 15 min when touching the chassi/enclosure, then it will be a lot less warm.  Not really sure why.

If one will be able to hold a finger to the BD transistors when operating, it should not be "possible" to hold it more than 5 seconds. There´s another story for the OpAmp, as it should not be too high in temperature - if so, there´s something wrong and it´s possibly oscillating, giving a distorted sound and shorting the life for it.

Of course you can get a bigger heatsink, and also a thick plate connected to all four, but I don´t recommend it becuse they may not reach their optimum working temp. In my LBC, each BD-139/140 has it´s own separate small heat sink connected to the tab with either thermal paste or silicon rubber. Then there´s a aluminium (formed as a upside down cup connected to the enclosure) over them with only a slight gap underneith it for air ventilation. This will raise the transistor temp also operate as a shield as the enclosure is a grid ventilated Power Supply from a PC.

https://www.digikey.se/en/datasheets/stmicroelectronics/stmicroelectronics-encd00001225


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## mikaelmark (Jan 1, 2020)

I asked at other forums the question about replacing the four 0,1uF caps for the LBC (and other audio gears as well), one guy has used a scope to measure if this will be an advantage or not - and he replied this should be good, but the values I suggest are not optimal as there will be some too high ringing.

Refer to the post from prairiedog 25th November: https://www.edaboard.com/showthread...ypass-cap%B4s-amp-gounding-speaker-basket%B4s

He suggest to use a capacitor at about 33nF with a resistor in series at about 330 Ohm, connected in parallel with the transformers secondary right before the head fuses (see my illustrating below):




 

Also remember; I was introduced to this Snubber by a guy that just recently has designed an headphone amp with a price of 2995$, more than twice the price for a Lehmann BCL SE with the standard 0,1uF caps for each rectifier!

Below are the reply I get from him:

"So this is called a snubber for the rectifier. Many dont really
understand these circuits or how to implement them, but here is a good
article.

https://diyaudioheaven.wordpress.com/tutorials/power-supplies/snubbering/

The best way is a single R and C in series across the transformer secondary.

To actually get a snubber to work correctly is not trivial and requires
knowledge of the transformer leakage inductance and rectifier stray
capacitance!"


----------



## mikaelmark (Dec 6, 2020)

Below are the modded schematic for my Power Stage, to be used with SparkoS Voltage Regulators LM1117-15 and LM7915:


----------



## mikaelmark

As I had some Rifa 47nF 630V laying, I choosed to soldered it to a 330Ohm 2W carbon resistor.

Within a few days, I´m gonna solder this Snubber to the voltage input for my Lovely Cube.

Will report back with my thoughts, when done!


----------



## mikaelmark (Feb 2, 2020)

When I connected the Snubber (a 47nF paralleled with a 330Ohm resistor), I realized the PCB already has a pair of soldering pads connected to the transformers secondary and the Heat Fuses input.

So, now I´ve done some listening with my HD800, and this LBC amp works tremendously well - those headphone are now full bodied and not so sibilant as they were earlier, altough the SS3602 much treble! Regarding the Snubber mod, it seem´s to do very vell, as the amp are has a really black background and plenty of tight and deep bass, so I can really recommend this mod for this amp, as well as it can be used with every amp, DAC and CD-player etc with AC Voltage input. Do´nt forget to remove the four original 0,1uF cap´s for the rectifiers.

Except the Snubber mod, I´ve also done following below to reduce noise and EMF/EMI:

- Replaced the cheaper 1N400x with BYV27 (as they´re faster and with less noise, giving a cleaner Power to the Voltage Regulators).

- Connected a filter (from a PC´s Power Supply) at the Primary side at the transformer.

- Mounted some aluminium brackets inside the amp (connected to the enclosure) for less noise from neighbour components.

- Applied some glue or double sided rubber adhesive tape between PCB and caps to reduce vibrating movement for them.

- Mounted some caps underneath the PCB at the secondary side (mostly due to their big size, but this may also reduce some inteference from other components).

- Connected the Voltage regs heating plates to chassi enclosure (Silica sheet or similar must be used between the tabs and heating plates, when doing this!).

- Shielded the internal OFC signal cables and the cable between the transformer and amp, connected to chassi Earth.

- Soldered the OpAmp directly to the PCB, without any socket (to avoid bad connection or oscillation from the PIN´s).

- Move the Toroid transformer out from the enclosure, in it´s own metal enclosure at a distance of about 8 inch.

- Connect the amp´s enclosure Earth to main wall outlet sockets Earth (if you have 3 PIN earthed wall outlets). This will help getting rid of any EMF/EMI noise and avoid letting it go towards the signal Earth that´s already separated with 1000pF cap and 100 Ohm resistor.


I will also add some rubber feet underneath the enclosure to minimize vibrations and a Ferrit bead to the high voltage cable, near the amp. And twisting the cables will also reduce EMF/EMI (at any direction; CW or CCW).


----------



## mikaelmark

I took some time to play with the black and white DIP switch settings label, and add some colour to it.

Note that I removed the High voltage warning and maked a Check for 220 Volt version.


----------



## mikaelmark

And here is an even more colourful one, once again a bit more modded:


----------



## mikaelmark

My LBC amp is working flawlessly perfect!


And as many people are worried about the amp are generating a lot of heat (mostly when used in BIAS Class A) and the enclosure has no ventilation holes, my solution about heat (sseen in the pictures above) was to use an aluminium plate to build a separate internal housing for the BD139/140 transistors, as those should generate most heat and will also benefit from higher temperatures than the other components.

For the outer enclosure, it has ventilation holes at the top to reduse heat to those.


----------



## Riversalt

Hello friends.
Is there an updated Diy version of this Lehmann amp that doesn't need to be modified / repaired?

I am not good with Diy mods pcb so I look for something ready made that I can only buy on Aliexpress.

But I see that everyone always needs a repair or another for fake or non-standard parts.

What do you suggest?


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## mikaelmark

Most of the China clone kits at eBay/Aliexpress will have the cheapest components, I suppose that´s the reason many amps will fail or measure badly. They also use to have blue coloured PCBs. Many caps and resistors will not have the best quality or correct values, but should however work (for one that are not to choosey). For example, many caps are Polyester, that are no good for audio - at least they should be MKP Polypropylene, or even better Polysterene or Teflon (depending what area they´re used). But I think the most critical are the transistors BD139-10 and BD140-10, that in the original should be -16. And don´t forget the volume control attenuator, as it usually are of worst thinkable quality! For the original, it will have a 50K Ohm Alps "Blue Velvet", that are pretty nice. But replacing it for an stepped attenuator, will take it to another level! About the resistors, they should at least be 1% tolerance Metal film (but upgrading to for example Dale, Holco or PRP9372 copper models are even better!).
And the original LBC, are using OPA2134, while the clones will only have JRC/NE5532 (the cheapest one can think of!). There´s really many to choose among, and discretes will be the best and most expensives.

From start, I purchased some kits, and when I realized above, I began to replace more and more of the components. So later, I purchased some upgraded green PCBs of high quality (thicker copper) from eBay, and then added my ownprefered components/parts. It has since then been more and more modding to them, as seen in my modded schematic.

My latest recently upgrade, are to replace the SparkoS SS3602 for their SS2590 (the discretes OpAmp Pro model, that will cost ~50% more and are HUGE in size!).

So everything will depends on how much money you what to spend; For a cheap standard China-kit at ~$40, you should not expect too much (maybe it´s a bit better than the worst thinkable integrated headphone amps, used in low budgets receivers). For a complete set with hand picked components, that will be equal to the original BCL (with an MSRP at ~$15.000), it will cost you ~$200. If one decide to go all the way with an insanely upgraded amp (as I almost have), one should be prepared to pay at least $500.

So however how deciding, the cost should be quite a bargain, if having the "know how"! If not, please ask and we will help you - that´s why we´re using this forum!

Don´t hesitate to start the project, as long as you have at least some basic knowledge and tools such as an soldering iron. And I promise you will have fun and learn a lot on they way!


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## mikaelmark

Or if anyone is interested, I can assemble a unit as I have components and PCB for spare. I live in Sweden, so preferable in Europe.


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## Dreddguy

Gentlemen. My first post in this hefty thread. While I wait for my BCL/c to arrive I was researching opamps and came across this YouTube.
Having being a victim of counterfeit opamps myself I thought this might be useful. 
You can skip the first 10 minutes.


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## Gsus01 (Jun 6, 2021)

It's finished and sounding great. It has a pop start but is dead silent with no music at any volume. it's amazing how it moves my dt990 pro 250ohm .  Very happy with the build.


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## core3m

Hello,
I have a  clone of the Lehmann Linear amplifier.
I am looking for the right opamp for it.
With OPA2134 the sound was too dry and too sharp. With the NE5532 it sounds too dry (but not sharp  ). 
Do you know any warm, analog opamp that would work here?


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