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Geshelli Archel2 Headphone AMP Review: another champ?

AnalogSteph

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@amirm Thank you for the test! I'm wondering why there is around a 10 dB difference in THD+N between the Archel2 and the THX 789 at low power levels, which should just be a measurement of noise, but they are pretty much the same in the 50 mV SNR test?
Same. For SNR re: 50 mV, look at ca. 76 µW into 33 ohms. This gets me ca. 92.5 dB for the Archel2 in low gain mode (correct) but only ca. 83 dB for the THX 789 at minimum gain. Is this because the standard THD+N vs. power test is run with the volume wide open, while the 50 mV test is not, thus reducing input stage noise accordingly (which would make sense when operating sensitive headphones)? That must be a really low-noise input stage in the Archel2 then, much like the O2.

I would also be interested in a measurement of input clipping level, in high gain in particular.

I think it's interesting that the difference in output noise level between low and high gain seems to be about 15 dB, despite the high gain being a nominal 4X (12 dB). Why would that be?

Yes, the pot would appear to not be quite up the same standard... channel tracking performance seems average at best, quite possibly it's a rather low value like 10k tops. That said, you've got a low (unity) gain mode, you shouldn't need that much attenuation anyway.
 
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This is my first post here because I spend most of my sleepless nights on Head Fi lol.

But I've been lucky enough to have the Geshelli Archel 2 for review and let me say this is one incredible little amp.

I've used it with every Headphone I could get my hands on Including my Sennheiser HD-600 and HD-650 as well as the Hifiman Sundara and it is an incredible little amp.

Easily the best I've heard in a the sub $300 price category .

Pairs very well with my Enog2 pro Dac
 

Noob

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I hope there will be a review and measurement of the original Archel Pro after this to compare how they have changed since the first iteration.
 

slmccaul

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Just ordered one. Don't listen to my 20+ year old HD 580's too often but couldn't resist. BTW, this is my first post here and I have appreciated all of the information, data and knowledge I have gleaned from this web site over the past 6-9 months. Thanks to everyone that has contributed, love it.
 

GrimSurfer

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If I were running a big audio company, I'd buy this guy's design and sell it with a fancier case for $399. Barring that, I'd offer him an in-house position and see what he could do with an infusion of resources and lab time.
 

bidn

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Excellent, invaluable review as usual, Amir!

It seems there is a typo above the 33 ohm graph:
"Switching to 300 ohm maintains the excellent performance but power is not as high as I like to see:"
Shouldn't it be 33 instead of 300?

[edit: found the answer: 600 ohm] BTW, sorry if this was asked already, but I would like to know which impedance is used for the 50 mV test?

Thank you again for your invaluable work and sanitization of the world of audio devices!
 
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theshakomaster

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Could we possibly slip a Khadas in that case.... looks like there’s a slot for it..... :)
 

Degru

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Power output seems a bit on the low side. My Fiio A5 portable amp exceeds it into low impedance and nearly matches it for high impedance. Though obviously with not nearly as good measurements, though should still be transparent. I wonder if it would be able to keep up the performance if it was built with higher power output.
 

bequietjk

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Had to order one. Just had to, in sky blue/clear.

What a wonderful time of audio this is.

Thank you ASR & Geshelli Labs. Cannot wait to hear this with my enog2.

I was just about to send my Archel Pro back to G Labs today for a gain adjustment, haha. I still might!
 

DuxServit

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Just ordered one.

Thanks Amir, ASR folks and Geshelli Labs.
 
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amirm

amirm

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Is this because the standard THD+N vs. power test is run with the volume wide open, while the 50 mV test is not, thus reducing input stage noise accordingly (which would make sense when operating sensitive headphones)?
Correct.
 
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amirm

amirm

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It seems there is a typo above the 33 ohm graph:
"Switching to 300 ohm maintains the excellent performance but power is not as high as I like to see:"
Shouldn't it be 33 instead of 300?
Yes, corrected.
 

maxxevv

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Could we possibly slip a Khadas in that case.... looks like there’s a slot for it..... :)

Definitely room in there for a E1DA 9038D (single ended version of the 9038s) though !

The only possible shortcoming I can think of is the slightly low power for low impedance loads. Insensitive planar headphones might pose an issue.
But its really clean output and low output impedance would make for an excellent desktop amp for super sensitive IEMS though.
 
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