Review and Measurements of Audio-gd NFB2 192 DAC

[Calexico]

Un test français
https://www.qobuz.com/LU-fr/info/Hi-Fi-Guide/Bancs-d-essai/Audio-gd-NFB-2-Qobuzissime-pour-ce177050
They talk about no feedback

 

[VintageFlanker]

Is there a single device from China, which is good for something?

Like a certain Chinese device which reached the limit measurable in the last review?...

 

[jasonq997]

Is there a single device from China, which is good for something?

This is the "Audio-GD of forum posts".

 

[LTig]

@amirm
Your didn't even listen in blind test. You've got lot of dacs. Why didn't you a/b test with a better measuring dac? Are you afraid of what you may prefer??
Some like these audio gd dacs. If you were a little curious you would experiment a/b tests as it's easy for you that have good measuring dacs.
They say no feedback measures bad but sounds good.
You say it's no true that it sounds good but you don't even tried to compare.
Excuse me but as you didn't even try to test if you ear was liking better or lesser you ve no credibility.
Your review is just free hate without any curiosity and no respect for people that like these kind of dacs with discrete no feedback output

Where is the dislike button?

Honestly, ASR is about true fidelity and not about nice sounding equipment. If I want to manipulate the sound I use my Behringer Ultrafex Pro or the tone controls in my AV processor (which I do for bad recordings), but I expect my hardware to put out what is put in with as low THD and noise as possible.

Feedback sounding bad is a myth. Just because somewhere in the 70ies one or two power amps were designed so badly that the feedback was too high and made them sound worse doesn't mean that feedback as such is bad. Actually feedback, if properly designed, makes everything better.

 

[MZKM]

They say no feedback measures bad but sounds good.

The mindset of this site is to find well-engineered gear, which means distortion-less, or at least as little distortion as possible. A $500 DAC with more distortion/jitter than a $100 is a bit inexcusable.

There are no studies that show that audible levels of second harmonics is more pleasing. Even if true, this unit has a lot of IMD as well, which we know is not-liked.

This unit also can’t accurately output 24Bit, another area where $100 DACs are much better.

As for no negative feedback measuring worse but sounds better, unless talking about having more distortion sounding better, that would imply that there is something that can’t be measured, which would be hard to prove.

 

[VintageFlanker]

Un test français
https://www.qobuz.com/LU-fr/info/Hi-Fi-Guide/Bancs-d-essai/Audio-gd-NFB-2-Qobuzissime-pour-ce177050
They talk about no feedback

Non pas Qobuz, par pitié !

Qobuz "reviews" are not revelant. The only good point I see is their teardrop part... After that, all listening tests worth nothing and they are ALWAYS positive about anything "for the price"... That plus their partnership with Audiophonics. Qobuz makes advertising by reviewing many products exclusively distributed by Audiophonics, then Audiophonics put the review's link on the product page.
Qobuz has responsibilities in the usurped popularity of Audio-GD in France.

Your review is just free hate without any curiosity and no respect for people that like these kind of dacs.

It's OK, @Calexico , your message/like ratio speaks for itself...

 

[garbulky]

Placebo based effects work this way. Since they are based on one's mindset and not auditory input, when that mindset changes in the future, so does impression of said gear. You want to know why high-end audiophiles keep changing gear? This is the main reason.

I do have a friend that forgets what made his original setup sound great and equate (what I think to be) a worse sounding piece of gear as being the same. This does tend to lead to "upgraditis" cycles.
I'm saying, I doubt these distortions you showed are going to be heard. If they are going to be heard causing say a "brighter" sound then yes I can see what you are saying.

 

[Calexico]

Where is the dislike button?

Honestly, ASR is about true fidelity and not about nice sounding equipment. If I want to manipulate the sound I use my Behringer Ultrafex Pro or the tone controls in my AV processor (which I do for bad recordings), but I expect my hardware to put out what is put in with as low THD and noise as possible.

Feedback sounding bad is a myth. Just because somewhere in the 70ies one or two power amps were designed so badly that the feedback was too high and made them sound worse doesn't mean that feedback as such is bad. Actually feedback, if properly designed, makes everything better.

So to you people that hear it sounds better are all crazy. And they don't care the bad specs.
But nobody on ASR is curious to test if they enjoy it.
That's not honest.

 

[garbulky]

The only issue here is that it's not a high quality dac. People might get mislead into thinking it's a high quality dac due to their inability to tell the faults with their ears, while in reality they could get better dac with $100 or even their onboard. I think this is the main benefit of this website, giving people the ability to see actual, measurable performance, and helping them make conscious decision when purchasing.

That's what I like about this website too. The measurements. Seeing them come up short from company spcifications is good to know too because it tells me if they are being honest.
But I do think people need to keep in perspectivbe that even vastly better measurements don't correlate to better sound once a (relatively low) bar has been acheived. I'm interested in knowing if it sounds better or worse and if so, by about how much.

 

[Calexico]

The mindset of this site is to find well-engineered gear, which means distortion-less, or at least as little distortion as possible. A $500 DAC with more distortion/jitter than a $100 is a bit inexcusable.

There are no studies that show that audible levels of second harmonics is more pleasing. Even if true, this unit has a lot of IMD as well, which we know is not-liked.

This unit also can’t accurately output 24Bit, another area where $100 DACs are much better.

As for no negative feedback measuring worse but sounds better, unless talking about having more distortion sounding better, that would imply that there is something that can’t be measured, which would be hard to prove.

Nobody say it's the harmonics that sounds good with no feedback.
Maybe measuring transients would show other things

 

[Calexico]

Negative feedback re-injects a sample of the amplifier’s output signal back into the input, 180 degrees out of phase, in an attempt to reduce amplifier non-linearity and distortion. In practice, negative feedback tends to slow the amplifier down and sucks the emotion and life out of the music. High feedback designs usually sound sterile, boring and lifeless, while low or zero feedback designs provide for a more immediate and natural sound.

 

[rmo]

Worse than Schiit

 

[Calexico]

http://www.atma-sphere.com/Resources/Paradigms_in_Amplifier_Design.php

Nice paper about negative feedback and no feedback.

 

[MZKM]

tends to slow the amplifier down and sucks the emotion and life out of the music.

Not true. Look at the 10kHz squarewave Stereophile has for all amps measured. If the transient was slower, the rise-time would take longer.

Slew rate is purely based on frequency range and power.

 

[LTig]

So to you people that hear it sounds better are all crazy. And they don't care the bad specs.
But nobody on ASR is curious to test if they enjoy it.
That's not honest.

No, I don't say that people are crazy when they decide to buy sounded equipment. It just is not my thing.

I have owned sounded equipment and liked it back then, because I fell victim to audiophilia. But finally switching to neutral gear made me more happy than ever.

 

[LTig]

Nobody say it's the harmonics that sounds good with no feedback.
Maybe measuring transients would show other things

Feedback makes an amplifier faster. Just compare the frequency response of an op-amp with open loop gain (just a few Hz) and closed loop gain (several MHz).

 

[LTig]

[..] In practice, negative feedback tends to slow the amplifier down [..]

This is just and plain wrong.

 

[amirm]

Negative feedback re-injects a sample of the amplifier’s output signal back into the input, 180 degrees out of phase, in an attempt to reduce amplifier non-linearity and distortion. In practice, negative feedback tends to slow the amplifier down and sucks the emotion and life out of the music. High feedback designs usually sound sterile, boring and lifeless, while low or zero feedback designs provide for a more immediate and natural sound.

You are in dire need of some real education. See https://www.edn.com/design/consumer...y-there-is-no-such-thing-as-too-much--Part-2-

That is written by a top notch engineer (Bruno Putzey), published in a real design magazine/website (Electronic Design News). He shows two amplifiers, one with a ton of feedback, and another with much less. He then throws a step function at them (which is illegal audio signal by the way):

One amp is darker, the other less. As you see, both perform identically without feedback (straight line) and with feedback (curved line). The curved line is there because the amps don't have infinite bandwidth which is not needed for audio. He notes:

He has a great rant at the end, justifying of this forum and reviews that I do:

So please, don't try to be your own brain surgeon, lawyer or doctor. Listen to people who truly understand the math and engineering here. Following lay intuition as you state, is only going to get you to overpaying for poorly designed equipment that likely sound worse, let alone the same or better.

 

[amirm]

Negative feedback re-injects a sample of the amplifier’s output signal back into the input, 180 degrees out of phase, in an attempt to reduce amplifier non-linearity and distortion. In practice, negative feedback tends to slow the amplifier down and sucks the emotion and life out of the music. High feedback designs usually sound sterile, boring and lifeless, while low or zero feedback designs provide for a more immediate and natural sound.

By the way, vast majority of music we listen to was produced via equipment that used feedback. How come the music was approved by the talent that way if "emotion and life" was sucked out of it before we even got it? And if that was sucked out, how on earth an amplifier is able to detect what is missing and invent it back in?

 

[AndrovichIV]

@amirm
Your didn't even listen in blind test. You've got lot of dacs. Why didn't you a/b test with a better measuring dac? Are you afraid of what you may prefer??
Some like these audio gd dacs. If you were a little curious you would experiment a/b tests as it's easy for you that have good measuring dacs.
They say no feedback measures bad but sounds good.
You say it's no true that it sounds good but you don't even tried to compare.
Excuse me but as you didn't even try to test if you ear was liking better or lesser you ve no credibility.
Your review is just free hate without any curiosity and no respect for people that like these kind of dacs with discrete no feedback output

If you want subjective reviews there's tons of websites such as HeadFi that you might wanna check.