Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Headphone Systems Everything to do with Headphones

Lehmann headphone amp clone on aliexpress
Lehmann headphone amp clone on aliexpress
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th October 2017, 04:01 AM   #21
asuslover is online now asuslover  Romania
diyAudio Member
 
Join Date: Aug 2016
Location: USA
Lehmann headphone amp clone on aliexpress
what do you guys think about this one:
High-end Stereo Class A Headphone Amplifier Board Amp PCB base Lehmann circuit | eBay
looks the same to me.
Attached Images
File Type: jpg s-l1600 (1).jpg (196.6 KB, 333 views)

Last edited by asuslover; 13th October 2017 at 04:05 AM.
  Reply With Quote
Old 13th October 2017, 04:15 AM   #22
abraxalito is offline abraxalito  United Kingdom
diyAudio Member
 
abraxalito's Avatar
 
Join Date: Sep 2007
Location: Hangzhou - Marco Polo's 'most beautiful city'. 700yrs is a long time though...
Send a message via Yahoo to abraxalito
In my experience, the classic Lehmann circuit was an almost total disaster for SQ. I blogged about it here : Bargain beaut - headphone amp - diyAudio
I cannot believe this is anywhere near classA as claimed - if it were so then the 10R emitter degeneration resistors in the output stage would be lower in value by maybe an order of magnitude or more.
__________________
I know you think you understand what you thought I said but I'm not sure you realize that what you heard is not what I meant - Alan Greenspan
  Reply With Quote
Old 13th October 2017, 04:23 AM   #23
rjm is offline rjm  Japan
Richard Murdey
diyAudio Member
 
rjm's Avatar
 
Join Date: May 2004
Location: Kyoto
Lehmann headphone amp clone on aliexpress
Quote:
Originally Posted by abraxalito View Post
Just say 'no' to classAB for headphones. As 99% of cans only need peak powers of a few h̶u̶n̶d̶r̶e̶d̶ mW, classA is the way to go.
ftfy
__________________
RJM Audio website|blog
  Reply With Quote
Old 13th October 2017, 05:40 AM   #24
ammel68 is offline ammel68  United States
Banned
 
Join Date: Sep 2009
Location: Southeast, U.S.
Lehmann headphone amp clone on aliexpress
Default My Lehmann Clone Finally Just Went into the Trash Where it Belongs!

This thread made me pull my Lehmann clone, which was built upon a blue PCB a few years ago, from a stack of projects that I had thrown over in the corner for trash in the near future.

After blowing the dust off it and connecting it to my recently purchased Niles SI-2100 Class D power amplifier, I was instantly greeted by some low-level hum with the volume all the way down.
So I did the ground rerouting as suggested in this post thinking it may be a ground loop:
100Hz Hum in Lehmann Linear clone
The ground rerouting in that post was a total waste of time and didn't make any difference with the low level hum, so I tried connecting all input and output grounds to the same point on the signal ground(op-amp) side of the board.
Still...there was low level hum, so I concluded that the LM317/337 on-board PS wasn't up to the job of keeping the hum(or ripple) out of the super-duper discreet "diamond buffer" section of this design.

Just for kicks...I tried this Lehmann clone with my plasma TV and cable box hoping for the best.
As soon as I turned the TV on, there was even more hum and other crazy noises amplified by this POS Lehmann clone to the point it was unlistenable.
It was at this point...I disconnected my Lehmann clone and threw straight it in the trash where I should have thrown it several years ago.

This got me thinking, so I tried my simple LM317/337 PS with Calvin's discrete buffer and experienced the same type of low level hum even though it only has a theoretically gain of one.
Switching over to my clone of Salas' DCSTB cap multiplier PS resulted in ZERO hum with Calvin's buffer, though I didn't waste my time lowering the voltage to see if it would lower the low level hum problem with the Lehmann clone.

So...there are 2 things that should be learned here ladies and gentlemen:
1. Don't waste your time and money on these "Lehmann Clone" kits with a on-board LM317/337 PS from eBay and Aliexpress unless you like a little 60 or 100 Hz "hum" to go along with your lower-level musical enjoyment. I don't but you may!
2. Don't even think about using a LM317/337 PS with a discrete amplifier design. These old regulators just aren't up to the job. Perhaps something that I should post over in the PS forums.

Last edited by ammel68; 13th October 2017 at 05:43 AM.
  Reply With Quote
Old 13th October 2017, 08:07 AM   #25
blackdod is offline blackdod  Europe
diyAudio Member
 
Join Date: Jun 2011
Location: Spain
A couple of years ago I made one with good quality components and I matched all; sand, resistors... I did some mod on the PSU regulation and spent a lot of time experimenting with several caps and OPAs.

I had no problems with noise or hum.

It's an interesting amp to learn.
Attached Images
File Type: jpg 2l44AqH.jpg (899.7 KB, 217 views)

Last edited by blackdod; 13th October 2017 at 08:14 AM.
  Reply With Quote
Old 14th October 2017, 10:50 PM   #26
Aatto is offline Aatto  United States
diyAudio Member
 
Aatto's Avatar
 
Join Date: Feb 2017
Location: Austin
Quote:
A couple of years ago I made one with good quality components and I matched all; sand, resistors... I did some mod on the PSU regulation and spent a lot of time experimenting with several caps and OPAs.

I had no problems with noise or hum.

It's an interesting amp to learn.
i m not sure what is going one here, with all the negative feedbacks i read here about these clones, i got this :
Lehmann HV-4 Headphone Amplifier Kit as i said, with its shitty components came with the kit ! the whole kit ( board+components+shipping ) was about 30 something dollars, but surprisingly it turned out quiet good actually, of course i replaced the shitty coupling caps with solen but other than that no tweaking what so ever, right out of the box, no noise no hum whatsoever and the sound quality is amazing very well balanced.
so i m not sure if this individual seller actually knows what they doing or i got lucky, but they have quiet interesting boards in their shop and i got myself another one of their boards just for fun, see how the other one will turn out.
blackdod, how do you like the sound quality ?

Last edited by Aatto; 14th October 2017 at 10:55 PM.
  Reply With Quote
Old 15th October 2017, 03:24 AM   #27
ammel68 is offline ammel68  United States
Banned
 
Join Date: Sep 2009
Location: Southeast, U.S.
Lehmann headphone amp clone on aliexpress
Aatto, you're "Lehmann HV-4 Kit" link above doesn't work for me.

My example used the older blue board like in this kit:
Kit Headphone Amplifier Board AC 15V-0-15V Reference Lehmann Circuit Design | eBay
I didn't use the same quality components that blackdod used with his example.
I did use Dale RN55 resistors to replace all the 1/4W Chinese resistors and larger Dale 1% 10 ohm emitter resistors for the BD139/140s.
I didn't use any coupling caps on the inputs since my sources didn't have any DC on their outputs.

For the power transformer, I used an old and reliable Rat Shack 12V-0V-12V 3A unit.
Initially, I used the supplied 1kuF 'lytics for the 6 caps in a row across the board.
Using 2kuF on the outputs of each of the LM3xx regulators is dumber-than-dammit since it's a well known fact that these old LM317/337 regulators will oscillate like hell with that much capacitance on their output pins.
So for curiosity, I reduced all 6 'lytics down to 220uf but there was no change in the hum.
At this point I unsoldered all 6 of my new Nichicon 220uF caps from the board and threw the board in the trash!
I don't have the time or patience for troubleshooting kits that should work the first time if assembled correctly.

Increasing the volume to get above the hum, I found my Lehmann clone's sound quality was fair at best despite trying about a dozen different op-amps. Some of these op-amps are some of the best sounding singles (OPA627 & ADA4627-1) on the planet when used in other applications, but made little difference in the sound of my Lehmann clone.

Whether or not the yellow boards you guys are using are "improved" in some way(s) to reduce the hum I don't know.
Nor will I be finding out since I don't plan on buying a yellow(or any other color) board and finding out.
  Reply With Quote
Old 15th October 2017, 02:41 PM   #28
Aatto is offline Aatto  United States
diyAudio Member
 
Aatto's Avatar
 
Join Date: Feb 2017
Location: Austin
try this :
GZLOZONE Lehmann HV-4 Headphone Amplifier Kit
no doubt these Chinese boards are a gamble, but sometimes it worth it, for 20-30 bux you won't feel that bad, i always burn in anything i buy with some cheap headphones or speakers, so if anything goes wrong i wont blow any precious stuff
  Reply With Quote
Old 16th October 2017, 04:59 AM   #29
ammel68 is offline ammel68  United States
Banned
 
Join Date: Sep 2009
Location: Southeast, U.S.
Lehmann headphone amp clone on aliexpress
I totally agree. If the project doesn't work out or should you not care for the sound, at least you haven't lost much money or time.
  Reply With Quote
Old 16th October 2017, 12:10 PM   #30
blackdod is offline blackdod  Europe
diyAudio Member
 
Join Date: Jun 2011
Location: Spain
Well I bought a clone with all components but I got curiosity and finally I spent enough money to leave it to my linking.

Pcb is of a normal quality but if you abuse it you'll probably take off the pads.

I don't know what brand are the resistors but in my case they were at 1% and I used some in non-critical places.

Caps. I checked volt/cap and all is Ok but I wasn't sure and I decided to use originals brands and others series (Nichicon Muse and KW and Mundorf Mcap and Mlytic).

Sand... here I used original components also in the place of the ones that come with the kit.

Unfortunately, some places are famous for selling fake sand and caps.

I never did the amp with the kit components so I can't say how it sound but giving you some care and changing various details you can have a "decent" headphone amp.

I'm not going to argue whether Lehmann's design is good or not. I have other very superior amps and they all have pro and cons.

My intention was to leave the amp to the maximum level with extremely precise measures without much alteration of the design.
  Reply With Quote

Reply


Lehmann headphone amp clone on aliexpressHide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
[Headamp] upgrading a Lehmann BCL clone Cidious Headphone Systems 386 5th July 2018 11:57 AM
I need headphone amp. Lehmann? thyristor44 Headphone Systems 21 5th May 2017 06:03 AM
100Hz Hum in Lehmann Linear clone PsychoM Headphone Systems 33 24th April 2017 08:35 AM
adding headphone jack to dynaco pas 3 clone rwshocker Tubes / Valves 1 27th December 2010 09:19 PM
lehmann headphone amplifier clone parhelia Headphone Systems 0 7th January 2010 01:00 PM


New To Site? Need Help?

All times are GMT. The time now is 01:45 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki