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Review and Measurements of Audio-gd DAC19 DAC

On a much more modest scale, I've built a number of loudspeakers for people I know. I have no measuring equipment at all now. I build from data and experience. In order for me to test and develop say a loudspeaker and provide any specifications regarding their performance I would need to acquire a lot of measuring equipment and spend countless hours doing the measuring.

I'm curious as to how you do this, if you don't mind me asking? Build from a design you've previously developed with measurements? Or model from factory data and trust the data and the models are accurate?
 
I'm curious as to how you do this, if you don't mind me asking? Build from a design you've previously developed with measurements? Or model from factory data and trust the data and the models are accurate?
I have 3 basic designs. I use the same drive units in each. The drive units came with matched impedance curves.
I did measure these designs many years ago (about 35 years ago in fact;))
The rest is done by calculation. It's science, it's all be done before. I do listen and tune by ear after for the couple I've made for domestic use. No they are not necessarily accurate but others I have build have gone to studios with DSP facilities and they tune to the room.
 
AudioGD's challenge machine has yet to be answered
AudioGD said:
Who need the AS-1:
AS-1 is not the lowest distortion DAC in world, but it had the ultra low distortion and price is not expensive.
AS-1 is not only declare with the words has low distortion, we offer the measure diagram for every single unit (It is normal that the THD has few DB different, the first 20 units offer AP SYS-2722 measure diagram, after that will offer AP ATS-2 measure diagram, ATS-2 measure diagram will has around 6DB worst than SYS-2722, but it is not mean the unit performance worse), verify by the professional instruments is welcome.
We known that the proper 2nd THD makes the sound become smooth and rich, the proper 3rd THD makes the sound become transparency and lively, how to adjust the level of 2nd and 3rd THD is the secret technology of the designers, that is why some audio devices have the higher distortion like phono, and some few very expensive European made audio devices had better musical to most people than some others low distortion devices .
We had not applied technology method to adjust the AS-1 THD effect the sound flavor, we just made it has the very low distortion , and through selected the different parts apply to keep the sound listening pleasant . It is not the audio-gd house sound style.
Who need the AS-1?
I guess that is in below:
1, Who concern the specs at first .
2, Who want a monitor sound to test the cable, room, speakers or somethings of audio.


http://www.audio-gd.com/Pro/dac/AS1/AS1EN.htm
 
There is a AudioGD R28 that looks like some of the other resistor ladder dacs. Uses a FPGA to trim the resistors to achieve better resolution. Might get 18 or 19 bit depth.
The R19 was replaced in 2016 and the replacement is discontinued. It is hard to build dacs today with 1704 chips. The chips cost more than some complete dacs.
 
Audio GD are still in business because despite all the golden eared audiophiles and the objectivists horror at the measurements, if you bought this dac and took it home you would probably be delighted with it's performance.
It's a strange thing about many objectivist forums, the mantra if it measures bad, it sounds bad, is just as bad as the subjectivists mantra, trust your ears...
Perhaps someone might be delighted by the look, by the appearance and by the fact that he brought a new "audiophile" device in his home, but nothing else. Roll-off starting at 3KHz is simply no performance at all, this is simply due to a poor design or implementation and there's no excuse for it. :(
 
[...] FYI Before I sent this off to Amir, I did an A/B comparison of this DAC-19 vs. the Topping D50 and could not tell the difference with statistical reliability. System used: FLAC files made from red book CDs via SPDIF, 50K Alps pots for volume control and A/B level matching, Harman-Kardon Citation II amplifier and Quad ESLs.[...]

I was actually expecting at least a small difference in sound, especially with songs containing lot of trebles; I am hoping you could please redo this test and perhaps record the outputs, so we can see Foobar's AB-comparator. A DAC that has so much roll-off on the trebles should definitely lack some of the details of the song. Maybe some contemporary Jazz could make you feel the differences in A/B test...worth trying.
 
Can the bad linearity be another case of ASIO4ALL bit truncation?
 
There are a number of other issues that I think are behind this discouraging lack of performance from allegedly high-end audio companies, besides the well known "placebo effects."

Speakers aside, the audible differences between reasonably well-designed pieces of gear a negligible. (Ignoring gear that deliberately distorts).

So why do people get so hung up on these things?

I conjecture the main reason is that they feel dissatisfied with the sound they are getting from their current system. This is where the speaker quality issue can really throw people off. Instead of looking at the speakers, placement, and room treatment, the dissatisfied listener reads about some new device that "opens up the soundstage" or whatever, and is convinced to buy.

Another reason is that the quality of the audio production, including the musical elements, vastly outweigh every aspect of reproduction system quality. (It's amazing how a really well-produced recording can sound great on a mediocre playback system, as an example from rock music, I'm consistently impressed with the production on Radiohead's records, after The Bends, these guys and their producer are at a whole other level...)

There is quite a range of quality in production, and it's a mind-bogglingly complex thing to get "right"...especially as this includes innumerable subjective factors. Every audio production you hear, except maybe purists stereo recordings, has gone through both analog and digital processing that introduces far more "distortion" than anything found in a competent playback system.

Another issue is that the critical listening skills required to evaluate any aspect of music (re)production are not trivial. Especially the ability to diagnose the cause of unhappy feelings when listening to recordings on your system.

One of the biggest problems in critical listening is that our perceptual system has "circuitry" that "fixes" problems in audio, the best it can, in real-time. There is simple test to illustrate how strong this effect is: find a playback system. It could be in the car, computer, it doesn't matter. It just needs to have reasonably easy to operate tone controls. Listen to 30secs of a song or so, then crank the bass all the up for 30secs, when you turn the bass back to flat the music will sound "tinny" lacking in bass. You will get the opposite effect with the treble control.

These perceptual effects combine with aspects of conscious attention to different parts of the musical sounds, of which there are often hundreds or thousands in a complex production.

Now consider again the multitude of sources of expectation bias, visual bias, emotional and physiological states that affect perception!

The result is that things never "sound the same." Each playback will sound different. The beginning of a single playblack will sound different from the end.

Combine this with the fact that we all only listen to a tiny subset of all possible recordings, usually of which we know little about the production itself, and it becomes very hard to decide whether something "sounds good"!

This can lead to "chasing your tail", switching in and out different parts of your system, one time thinking this amp sounds so much better, another time being convinced that the converters in your old CD player sound much different than these new-fangled DACs!!!

For myself, the advantage of having a piece of gear that measures up to a standard level of performance is that at least I can "rule it out" as being the source of frustration with my music listening experience.

---

March's point about it not necessarily costing more to manufacture good performing audio gear is well put.

While I think getting the best audio performance "just for the sake of it" is an interesting project in-and-of-itself, it's interesting how it can also lead to the exact same phenomena that peddlers of "snake oil" products rely upon! Expectation bias.

What I would like to see from audio companies is focus on hitting a specified level of performance that is "good enough" in that gains beyond are not audible. Then the buyer could "rest easy" in this aspect of purchasing. There remains plenty of room for improvement in many other aspects of equipment design:

- cost, manufacturing cost, green production techniques

- proper safety design and testing

- reliability/repairability

- upgradability, mod-ability

- features, it's surprising how hard it still is to find gear at the price you want that has the right combination of features!

(I want an affordable DAC/amp that would run custom dsp EQ curves. Look at the massive amount of functionality found in the average AVR, for the price. Basically, a product that strips that down to a USB input, spdif input, and maybe two rca inputs would do the trick. There's already extensive dsp capabilities in these AVRs, there should be more than enough horsepower to run 6 channels of parametric EQ or so. But there is no good way to access it in current AVRs, Leave out all the extra stuff, making it smaller and cooler.)

- ergonomic issues...the functioning of the controls on an AV playback system is a huge factor in subjective performance. Just having tone controls vs having to go into submenus with the remote makes a concrete difference. Likewise with the resolution of the volume control. The amount of gain, and the taper of the control, can have a big affect on how I "feel" about a system.

- power consumption/heat relative to performance

- size, physical design, weight
 
Can the bad linearity be another case of ASIO4ALL bit truncation?
It may be contributing to it. Whether it is all of it, is hard to say. It may also be that ASIO4ALL is working well and it is the DAC that is doing the truncation.
 
It may be contributing to it. Whether it is all of it, is hard to say. It may also be that ASIO4ALL is working well and it is the DAC that is doing the truncation.

That would be odd as PCM1704 is a 24 bit part. Try SPDIF maybe? Could also be those internal jumpers aren't set right.
 
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I keep reading overly enthusiastic reviews of Audio-GD products by audiophiles. I think this has to do, indeed, with the massive constructions of these devices that plays well with most audiophiles prejudices. It's also clear that these devices clearly lack any QA/QC.

We know by now that huge discrete designs are not needed to make something high-performance (from the ODAC to the Khadas Tone Board or even the RME ADI-2 DAC if you go to higher tiers), but apparently they sell much better.

It's fun though that the same audiophiles advocating for high-res and extreme DSD upsamplings end up praising DACs that are barely good for 16 bit reproduction. Probably we should simply accept that subjective listening has very little to do with the quality of the gear and that most of the audiophile community is simply delusional.
 
It has lost the path for a very long time. The cable industry, mechanical isolation, power conditioners, and other high profit items are all for ego building.
The opposite end is the products like the Tone board. Wonder how they make a profit. But that is a good thing for buyers.
 
What do you mean that its yet to be answered?
AudioGD built the AS-1 in response to ASR's bad measurements of audio-gd products. I figured ASR would accept the challenge of measuring the AS-1 and therefore proving that audio-gd's goal isn't perfect measurements but a good "knowledge" of "musicality" in electronics yet capable of building a "perfectly measured" machine for ASR review method.
 
AudioGD built the AS-1 in response to ASR's bad measurements of audio-gd products. I figured ASR would accept the challenge of measuring the AS-1 and therefore proving that audio-gd's goal isn't perfect measurements but a good "knowledge" of "musicality" in electronics yet capable of building a "perfectly measured" machine for ASR review method.

If "musicality" (assuming it's a real concept) is achieved by designing products with intended high noise and distortion, why do they have to be expensive and use high-end digital chips and selected components?
 
AudioGD built the AS-1 in response to ASR's bad measurements of audio-gd products. I figured ASR would accept the challenge of measuring the AS-1 and therefore proving that audio-gd's goal isn't perfect measurements but a good "knowledge" of "musicality" in electronics yet capable of building a "perfectly measured" machine for ASR review method.
If that is the case, they should have contacted me and send one in for review. The only reason it is not reviewed is because no one who owns one has sent one in, not that we are afraid of testing it.
 
control, ability and hype parts

Something like an ADAU1701, which costs under $20 and has four inbuilt DAs, could do all this with DSP, giving greater control over the distortion transfer function than with physical circuits.
 
If "musicality" (assuming it's a real concept) is achieved by designing products with intended high noise and distortion, why do they have to be expensive and use high-end digital chips and selected components?
Because they can.
 
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