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post #1291 of 1304

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.


Edited by mayday75 - 6/6/15 at 2:19am
post #1292 of 1304

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.

post #1293 of 1304

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

post #1294 of 1304
Quote:
Originally Posted by mayday75 View Post
 

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.

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. 

post #1295 of 1304

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.

post #1296 of 1304
Quote:
Originally Posted by mikaelmark View Post
 

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.

post #1297 of 1304
Quote:
Originally Posted by mayday75 View Post
 

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.

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?

post #1298 of 1304
Quote:
Originally Posted by mikaelmark View Post
 

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.

post #1299 of 1304

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.

post #1300 of 1304
Quote:
 

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.

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.

post #1301 of 1304
Quote:
Originally Posted by mikaelmark View Post
 

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.

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?

post #1302 of 1304

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?


Edited by Expansion - 6/29/15 at 12:52am
post #1303 of 1304
Thread Starter 
Quote:
Originally Posted by Expansion View Post
 

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?

 

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. 

post #1304 of 1304
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
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