Lehmann headphone amp clone on aliexpress

what do you think ?
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component placement looks like the original
aliexpress link
 

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what do you think ?

These "Lehmann" clone boards have been discussed many times here before.

Having personally built a couple of these "Lehmann clones" in the past, I would forgot about this sh_tty sounding design and move on to something else!
Utilizing a dual op-amp(OPA2134 or whatever dual JFET op-amp you prefer) for the VGS is one of the limiting factors here vs. using a single op-amp for each channel.

Look for a JLH headphone amp PCB if you're determined to try one of these Chinese clone headphone amps.
The all discreet JLH desing sounds MUCHO better IMHO, but will require a DC servo to keep the offset from possibly "frying" your headphones.
 
huh, i was just wondering how the hell they cloned a 1000$ product into a 30$ kit !
i got another board from the same company i believe and the seller claimed that this circuit is also based on lehmann :
GZLOZONE Lehmann HV-4 Headphone Amplifier Kit With ALPS 27 Type Potentiometer

i put it together with its all crappy components, the only thing i changed was the coupling caps which i replaced with solen ones and man it surprised me, it sounds fantastic, no noise no hum , dead quite and looks like a good design overall, so i got lucky you think ?
 
From my limited experience of browsing (but not buying) amps Zerozone is one of the better guys. The full kit is only about $5 more than the bare PCB, a real bargain. To protect your precious cans I'd AC couple the output rather than rely on trimming the DC offset though.
 
i got 250ohm, so about 300uf ?
few more questions :
- does the cap have any effect on the sound, i read it effects bass., is the brand effect the sound character , like solen, m-caps ... ?
-is there any more general solution ? like if i want to switch between different impedance cans without worrying about cap value ?
 
Yeah, 250ohm would suit 330uF (nearest standard value).

There are plenty of guys who hear differences between caps, I'm not one of them (yet). So I use a bog-standard electrolytic. Preferably not a low ESR one unless that's all you have as lower ESR normally means higher leakage.

You can size your cap according to the lowest impedance 'phones you're going to use. The only downside is a bigger (longer) switch-on 'thump' with the higher-Z kinds. This can be minimized though by fitting resistors (say 1k ohm) across your jack outputs to provide the ability to charge the cap with nothing plugged in. Then only plug in your cans a few seconds after powering up.
 
i like that !
i found this for JLH :
NEW JLH HOOD1969 Class A Headphone amplifier PCB

what do you think ?
any suggestions on ebay/aliexpress ?

As I stated above, IMO the JLH smokes the Lehmann clones for SQ.
You can "roll" all the dual op-amps you want, but it still won't match the JLH's SQ.

DC offset is a big problem with the JLH and varies wildly depending on the temperature of the output devices.
Better AC couple that one for sure as abraxalito suggests.
 
Yeah, 250ohm would suit 330uF (nearest standard value).

There are plenty of guys who hear differences between caps, I'm not one of them (yet). So I use a bog-standard electrolytic. Preferably not a low ESR one unless that's all you have as lower ESR normally means higher leakage.

You can size your cap according to the lowest impedance 'phones you're going to use. The only downside is a bigger (longer) switch-on 'thump' with the higher-Z kinds. This can be minimized though by fitting resistors (say 1k ohm) across your jack outputs to provide the ability to charge the cap with nothing plugged in. Then only plug in your cans a few seconds after powering up.

will do the coupling thanks for the input :)
 
Their Beyerdynamik A-1 copy is quite good, comparing to its price. (200 bucks or so)

yeah i did gave that one a try while back,i was happy with it till i tried this one :
GZLOZONE Lehmann HV-4 Headphone Amplifier Kit

As I stated above, IMO the JLH smokes the Lehmann clones for SQ.
You can "roll" all the dual op-amps you want, but it still won't match the JLH's SQ.

DC offset is a big problem with the JLH and varies wildly depending on the temperature of the output devices.
Better AC couple that one for sure as abraxalito suggests.

I already bought this one a few weeks back :

GZLOZONE HV-5-TB Headphone amplifier PCB
i wanted to give this one a try since i had good experience with GZLOZONE before and since it's hybrid. there's no info on the board, lol, took a risk :D

JLH is next on the list :D
 
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I already bought this one a few weeks back :

GZLOZONE HV-5-TB Headphone amplifier PCB
i wanted to give this one a try since i had good experience with GZLOZONE before and since it's hybrid. there's no info on the board, lol, took a risk :D

Hmm...I've never seen that board before. Looks to be quite complex and uses a lot of components.
I have to agree that you took a BIG chance on that one, especially since I don't see a schematic for it.
Best of luck assembling it & working all the bugs out...LOL.
 
Hmm...I've never seen that board before. Looks to be quite complex and uses a lot of components.
I have to agree that you took a BIG chance on that one, especially since I don't see a schematic for it.
Best of luck assembling it & working all the bugs out...LOL.

i m very pleased with how it turned out tho, as for this board yeah, i m hoping for the best ( and not preparing for the worst ! ) lol, i ll let you know how it turned out, i ll probably receive it in a week or so.

pic from finished GZLOZONE Lehmann HV-4 amp :
 

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I believe Sennheiser chose the Lehmann BCL amp to power their HD800 headphones at the launch. You might think they know a thing or two about headphones and amps, so surely the BCL can't be that bad??

Like most kit they can be tweaked to some extent for better sound, primarily the power supply.
 
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it does not mean if they manufacture speakers/headphones they know everything about the amps or the other way around, if you are a painter it does not mean you know how paint was made or how to make it ! but as a experienced painter you know what paint to choose.
Lehmann has a good reputation and i m sure guys at Sennheiser tried different amps before they choose one , or it's like a contract or something.