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Lehmann headphone amp clone on aliexpress
Lehmann headphone amp clone on aliexpress
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Old 29th October 2017, 05:56 AM   #61
ammel68 is offline ammel68  United States
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Lehmann headphone amp clone on aliexpress
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Originally Posted by Aatto View Post
wow, such stubborn guy, does not accept that others may have success with their build . i dont wanna argue with you but just fyi my other lehmann clone works absolutely dead quiet too, no audible hum/noise.
No stubborn guy here Aatto...I personally don't give a big, fat damn if others here have success with their "dead quiet" builds, or not. Can you please understand that???
My carefully crafted and assembled Lehmann clones have gone straight into the trash where they belong, since they weren't quiet enough with my EPB fiber optics cable box and my 42" plasma display.
If you're using your Lehmann clone with other sources(like a CD player or music streamer), then it may very well be quiet enough for these sources.

FWIW...I don't really care since there are other headphone amplifiers out there that literally "mop the floor" with these junky a$$ Lehmann clones such as the Schiit Audio Magni 3, which I received a few days ago:
Schiit Audio, Headphone amps and DACs made in USA.
UNBELIEVABLE SQ for only $100.

Good bye Lehmann!!
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Old 30th October 2017, 12:56 AM   #62
madisonears is offline madisonears  United States
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Does the input impedance of this amp vary with volume control setting? It is the first element connected to ground in the input path and the only thing other than a 10k resistor in series with the opamp input. Is that a good design? Any way to "fix" it if it's not a good design?

I just bought the bare pcb. I recognize that the full kit consists mostly of junk and counterfeit parts. There is no way even the Chinese can sell a complete amp with a genuine Alps pot and other parts for such little money. I intend to populate the board with decent parts and a couple boutique parts such as a bulk foil resistor in the opamp feedback loop. I've heard the difference that can make in other circuits and I think it might be worth the cost even in this crude amp.

Peace,
Tom E
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Old 30th October 2017, 10:59 PM   #63
Aatto is offline Aatto  United States
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donno about this one, but the other lehmann clone have constant input impedance of 50k ( if i remember correctly). as for the parts god knows how they come with such cheap prices, altho the only part i changed on mine was the input coupling caps, and it did make a huge difference.
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Old 31st October 2017, 01:43 AM   #64
madisonears is offline madisonears  United States
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Parts Express sells this populated pcb and all a buyer needs to do is attach a transformer. It is stated in the specs and in Lehman's own specs that the input imp is 47k, so I guess that's what it is. Everything else I've read says that a volume control in this position will alter input impedance, at least to some extent, and the challenge in any such design is what value pot to use. The BOM calls for 50k, but I'm wondering if that's ideal. A lot depends on output imp of upstream device. I'm taking PC outputs, and I have no idea what that output imp is.

There are two reviews at PE: one review says the amp is quiet, the other complains about hum. Seems like a real coin toss with this design, or perhaps it has to do with connected components.

Peace,
Tom E
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Old 31st October 2017, 02:48 AM   #65
Aatto is offline Aatto  United States
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huh, never seen the PE one, but TBH the board n components look sh$$$y.
as we all discuss it really is a coin toss, i couldn't be happier with mine even though it's all chinese components.
but now even with the good luck i had in the past , i wont bother buying the whole kit, go for the board, and take a look at JLH and nac52 clones as well, people here had better experience with those.
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Old 27th February 2018, 05:13 PM   #66
madisonears is offline madisonears  United States
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Finally completed the Lehmann clone amp, and it is absolutely dead nuts quiet through headphones. Volume cranked, and nothing. It's sitting right on top of my computer with no special cabling or shielding. I made one modification to the stock design: instead of taking the pre-amp outputs off the board by way of the narrow traces that run directly under the power supply, I attached a twisted trio directly to the headphone jacks solder pads and ran them along the "quiet" side of the board to the output jacks at the rear of the amp. Now there is no signal path element anywhere near the power supply.

Can't tell much about the sound yet as I just powered it up. Nothing seems bad, but it's too early to tell if it's really good. It certainly has excellent clarity, but I would expect the sound to warm up a little after some hours of play. I have not yet tried the pre-amp outputs, but I measured DC offset at the output jacks and got 1.3 and 1.1 mv without shorting the inputs. Does that seem good?

I don't hear any on-off pops, so I'm guessing DC at headphone jacks is minimal.

Peace,
Tom E
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Old 5th March 2018, 01:21 PM   #67
Aatto is offline Aatto  United States
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glad to hear you have good luck with yours, i also finished mine about a week ago, getting the preamp out directly from the front head out sounds like a good idea since i get some hum and other noises when i crank it up using it as a preamp. but headphones out is dead quiet.
I got the same results as yours and i like the sound, it is clear and it certainly has a character, nothing to color the sound much may be the character is the flatness.
i used it more as a preamp rather than listening through headphones but i will put it to work once i put a case together.
overall i like it and i m building another one for a friend of mine to use it in a studio environment.
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Old 5th March 2018, 01:27 PM   #68
Aatto is offline Aatto  United States
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