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Audio-GD NFB-11.38 Performance Edition Measurements (DAC, Preamp & Headamp)

garbz

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I had an earlier version and as you can see there are a lot of discrete components. It stopped functioning just after a year.
I am not surprised. Even without the mods that assembly looks amateurish at best.
No I take that back. Many amateurs have higher standards than that.

Those mods are a disgrace from the original manufacturer as well.
 

tvih

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Because it's a DAC/pre/headamp for under €500.
Well his point was others doing it with a remote... which my Topping DX3 Pro+ that costs 200 can also do? So why not something costing more than double that?

Not that I personally even need filter settings, but when it's a feature on the product it should also be usable in a reasonable manner. Hardly an unreasonable point of view.
 

PeteL

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In my opinion, adding subjective impressions of this DAC/amp would add nothing to the review. Speakers and headphones are another story though.
I think that relative audibility of measured performance flaws is a greatly unexploited subject in the state of where knowledge is of audio reproduction. It does add something to know if trained ears can detect audible degradation , because in he long run, this knowledge base may lead to better mesurment metrics, so far the audibility tresholds are highly theoretical and don’t have any statistical data to back them. it is very likely that those limitations in knowledge are stearing manufacturers in chasing measurment metrics in directions that serves no purpose. And this is not what good engineering is, doing stuff that has no impact on what an audio product is suppose to achieve which is to be percieved by eardrums and ultimately brain, if engineering ressources and money is spent toward something that has no impact on that, it is poor use of intelligence. Audibility matters, in fact it’s all that matter.
 
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acbarn

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I think that relative audibility of measured performance flaws is a greatly unexploited subject in the state of where knowledge is of audio reproduction. It does add something to know if trained ears can detect audible degradation , because in he long run, this knowledge base may lead to better mesurment metrics, so far the audibility tresholds are highly theoretical and don’t have any statistical data to back them. it is very likely that those limitations in knowledge are stearing manufacturers in chasing measurment metrics in directions that serves no purpose. And this is not what good engineering is, doing stuff that has no impact on what an audio product is suppose to achieve which is to be percieved by eardrums and ultimately brain, if engineering ressources and money is spent toward something that has no impact on that, it is poor use of intelligence. Audibility matters, in fact it’s all that matter.
Determining audibility thresholds is important, no argument there. But the subjective impressions of one reviewer in an uncontrolled listening situation doesn’t provide any useful data to help reach that goal.
 

IVX

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when I worked on the Cosmos ADC design I tried many oscillators to clock ES9822 which appeared to be very sensitive to the jitter, you can see that on the resulting SNR directly. Of course, I tried Accusilicon as well but I found that just an average between NDK NZ2520SD(slightly worse vs Accusilicon) and Epson SG-210STF(slightly better vs Accusilicon). I have to say, that NZ2520SD and SG-210STF price is $.5 but Accusilicon $10.
Inside of the huge Accusilicon case, I found the same sized 2520 SMD oscillator ))
3dcc683fb89459b7810676ea7a4f373.jpg
 

TheBatsEar

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TheBatsEar

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OP
VintageFlanker

VintageFlanker

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Is there a post somewhere where you explain your measurement setup in detail?
You got everything in the disclaimer.;)

All measurements are done with a dedicated laptop, and only when battery-powered (affects performance when measuring unbalanced outputs).
IMG-20220413-WA0004(1).jpg
 

audiofun

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You got everything in the disclaimer.;)

All measurements are done with a dedicated laptop, and only when battery-powered (affects performance when measuring unbalanced outputs).View attachment 201338
you created a ground loop when measuring this way.
computer -> USB->COAX->DAC->ADC->USB->computer.
You need two laptop computers on battery to measure coax and usb properly, and do nor form a loop.
 
OP
VintageFlanker

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you created a ground loop when measuring this way.
computer -> USB->COAX->DAC->ADC->USB->computer.
I agree for the first part, if it was with a regular desktop PC (as it was a repeatable case in my previous measurements). Battery-powered when measuring unbalanced killed this issue (with whatever Coax or USB, toslink also had concerns) with just any others DACs I've on hands but this one. None loopback software measurements could be done with two separate laptops, BTW.;)

At the end, if Coax/USB is sensitive to loop, it is Audio GD's fault.
 

audiofun

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I agree for the first part, if it was with a regular desktop PC (as it was a repeatable case in my previous measurements). Battery-powered when measuring unbalanced killed this issue (with whatever Coax or USB, toslink also had concerns) with just any others DACs I've on hands but this one. None loopback software measurements could be done with two separate laptops, BTW.;)

At the end, if Coax/USB is sensitive to loop, it is Audio GD's fault.
Not really. Any top performing unbalanced DACs I have produces ground noise when connected this way. See experiment.
You're just holding it wrong. I regard AudioGD as scam. but in your ground loop case, it's not their fault.
 

milosz

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Nice job. I wonder if some people prefer the elevated 2nd harmonic that this thing produces? Even though the 2nd harmonic level is higher than good quality DACs made these days, it is still pretty low in objective terms - THD + Noise (at -3 dB FS) plot shows it at about -90 dB. Can people hear an added 2nd harmonic that is 90 dB down? If you were playing music from your system with an in-room level of 100 dB SPL (which is damned loud, really) wouldn't something in the playback that is 90 dB below that level actually be quieter than the approx 20~30 dB SPL of ambient noise in the typical living room?

Yeah it doesn't measure that great; one can buy better these days at bargain prices. But I really doubt many of us here - IF ANY!- could actually hear the difference in a blind A/B of this DAC vs a good Topping unit.

We really need a Audioscience Psychoacoustics Review to submit some of this gear to a population of listeners in well designed blind A/B tests, and maybe also some blind "long listening tests" that some seem to prefer.
 

pkane

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I agree for the first part, if it was with a regular desktop PC (as it was a repeatable case in my previous measurements). Battery-powered when measuring unbalanced killed this issue (with whatever Coax or USB, toslink also had concerns) with just any others DACs I've on hands but this one. None loopback software measurements could be done with two separate laptops, BTW.;)

At the end, if Coax/USB is sensitive to loop, it is Audio GD's fault.

Hi @VintageFlanker ,

I'm very much enjoying reading your measurements and reviews, keep it up!

Between coax and USB there's still a possibility of a ground loop even on laptop batteries, but an optical input is guaranteed to break it. If toslink doesn't show the same level of noise, you may have a ground loop (a difference of potential between grounds). It may be worth investigating connecting grounds between the laptop and the DAC, and/or between the DAC and the ADC by a short thick wire to see if this effect can be reduced or eliminated.
 
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