Worlds Greatest DAC and what it does differently

[beerandmusic]

On 6/10/2020 at 11:31 AM, pkane2001 said:

 

If you are looking at the differences in the human-audible range, these "VAST" differences would be a VAST exaggeration. A 1kHz sine wave reproduced by most competently designed DACs (possibly excluding some NOS R2R types) will look like a 1kHz analog sine wave. You'll need to zoom in with a magnification of 10,000x times or more to start to see some minor differences, and that would be with some of the poorer performing DACs.

Just out of curiosity, you said vast differences would be a vast exaggeration except for certain pcm dacs....What pcm dacs would be more accurate?  I really don't want to have to build a fancy computer with fancy power supply to handle high rate dsd if pcm 192k would be sufficient...is there a PCM dac that would do better at accuracy that you could recommend or are you in the DSD camp?

[Miska]

16 hours ago, beerandmusic said:

MISKA>> mandatory ones being such as 128 kbps MP3

huh?  i dont get this statement?

 

Reason why DLNA was created is that UPnP AV specification doesn't say anything about any file formats. So you could have two different devices that don't have support for any file format in common. So DLNA specification was created to specify set of mandatory and optional file formats a UPnP device needs to support to be DLNA compliant. This includes both audio and video formats.

 

One of the mandatory supported file formats in DLNA is 128 kbps CBR stereo 44.1 kHz MP3.

 

DLNA is about file format support for UPnP AV protocol.

 

16 hours ago, beerandmusic said:

I can stream DSD256 via dlna..i have been doing so for over 5 years...or are you just saying you can only do somethings with mp3 files?  I have replaced all my mp3's with wav or dsd.

 

You can maybe stream it over UPnP AV, but not via DLNA, because DLNA specification doesn't know anything about DSD. Such formats fall outside of DLNA scope and naturally work over UPnP AV.

 

IOW, DLNA specification just amends UPnP AV specification with set of file formats to ensure that devices would have some common baseline formats so that you can always get some audio or video output.

 

[davide256]

On 6/12/2020 at 5:45 PM, Miska said:

 

It could be inside the DAC, or outside of the DAC. I'm doing it in player software.

 

And yes, I'm talking about analog output of the DAC too. Modern DACs heavily rely on DSP algorithms, to the extent that DSP algorithms largely define base performance of the DAC.

 

Example; here you can see Holo Audio Spring 2 DAC running with 1 kHz -120 dBFS input, TPDF dithered to 24-bit, at 1.4112M sampling rate:

 

And here the same, but data noise-shaped to 20-bit to match linear range of the R2R ladder:

 

You can see that the second one is at least 20 dB (10x) cleaner! In fact it is much more than 10x cleaner, while having actually more dynamic range, but limited by analog noise floor.

 

Another view, here is same DAC running sweep with built-in oversampling (8x) to 352.8k:

 

You can see that the first image around 352.8k is at -60 dB meaning about 10-bit equivalent reconstruction accuracy. And actually four image pair bands visible. At 192k sampling rate it would be much worse.

 

Here's the same, but at 1.4112M sampling rate with oversampling done in player software:

 

You can see there there are no images at least clearly visible at multiples of 1.4112M sampling rate. The difference here is more than 40 dB (100x)!

 

And here's the same again at DSD512:

 

Here you can see that within about 100 dB range, 1.4112M PCM through R2R section and DSD through the DSD section produce similar image levels on this DAC, so we can reach at least decent RedBook reconstruction.

 

In all cases, source file is 44.1k sampling rate. We could also look into narrower spectrum to see differences in there.

 

 

This is just a very brief example what DSP can do to operate the conversion section to perform well.

 

Does the width of the blue band determine imaging stability?  seems to me the wider the band, the greater the deviance in volume reproduction  for overtones.

[pkane2001]

13 hours ago, beerandmusic said:

Just out of curiosity, you said vast differences would be a vast exaggeration except for certain pcm dacs....What pcm dacs would be more accurate?  I really don't want to have to build a fancy computer with fancy power supply to handle high rate dsd if pcm 192k would be sufficient...is there a PCM dac that would do better at accuracy that you could recommend or are you in the DSD camp?

 

I find DSD and PCM pretty much interchangeable, although PCM is much simpler to use in my application since I use various plugins and convolution filters as part of my audio chain. R2R NOS DACs with no software oversampling/filtering are not the correct (mathematically) way to reproduce sound. They introduce significant distortions and a stair-case waveforms, especially at lower levels, that look nothing like the original signal. This can all be fixed with proper filtering and oversampling in the DAC or in software, such as HQP. Of course, there are those who find the poorly reproduced R2R NOS audio to sound better. But it's not because it's more 'natural' or more 'accurate', quite the opposite.

[beerandmusic]

1 hour ago, pkane2001 said:

 

I find DSD and PCM pretty much interchangeable, although PCM is much simpler to use in my application since I use various plugins and convolution filters as part of my audio chain. R2R NOS DACs with no software oversampling/filtering are not the correct (mathematically) way to reproduce sound. They introduce significant distortions and a stair-case waveforms, especially at lower levels, that look nothing like the original signal. This can all be fixed with proper filtering and oversampling in the DAC or in software, such as HQP. Of course, there are those who find the poorly reproduced R2R NOS audio to sound better. But it's not because it's more 'natural' or more 'accurate', quite the opposite.

Don't schiit multibit oversample/upsample? Or they just don't upsample high enough?  I was wondering if you had a recommendation for a "non-diy" PCM dac....or DSD dac that does both PCM and DSD equally well? Many seem to like RME adi-2 and Topping D90?  Would it possibly be beneficial to get an older higher end used pcm dac like ayre or emm?  As you know, it seems everyone on ASR believe all dacs that measure well sound exactly the same...do you fall in that same camp?

[Miska]

18 minutes ago, beerandmusic said:

Don't schiit multibit oversample/upsample? Or they just don't it high enough?

 

Cheaper Schiit devices run at 176.4/192k over/up-sampling on a tiny DSP. That is not high enough. It is like CD player's from late 80's. But note that on those CD players they would know that source is always 44.1k sampling rate, nothing else. They didn't need to accommodate any hires in the analog filter design. However the analog filter had corner very close to 20 kHz and thus having adverse phase effects in audio band. Later higher digital filter DAC output rates (352.8k and 705.6k) allowed less intrusive analog filter. Still not perfect, but already much better.

 

More expensive models do 352.8/384k which is already better and same as many DAC chips do. That gets you a little bit closer to proper reconstruction. Depending on analog filter something like 60 dB (~10-bit) accuracy.

 

Then of course another question is quality of the upsampling filters and what kind of response they have. Resulting accuracy in DAC chip filters is in range of 8-bit to 20-bit equivalent.

 

[Miska]

2 hours ago, davide256 said:

Does the width of the blue band determine imaging stability?  seems to me the wider the band, the greater the deviance in volume reproduction  for overtones.

 

What do you mean width on blue band? Width of the two images around multiples of output sampling rate is 22.05 kHz which is Nyquist band of the original 0 - 22.05 kHz sweep. Left peak are negative frequencies (inverse spectrum) and right peak is positive frequencies. In the middle is multiple of sampling rate. These images are result of "stair step" pattern in the output waveform that analog filter has not been able to completely smooth out.

[pkane2001]

1 hour ago, beerandmusic said:

Don't schiit multibit oversample/upsample? Or they just don't upsample high enough?  I was wondering if you had a recommendation for a "non-diy" PCM dac....or DSD dac that does both PCM and DSD equally well? Many seem to like RME adi-2 and Topping D90?  Would it possibly be beneficial to get an older higher end used pcm dac like ayre or emm?  As you know, it seems everyone on ASR believe all dacs that measure well sound exactly the same...do you fall in that same camp?

 

No idea. Haven't seen a Schiit DAC in person or ever considered one. Measurements I've seen have been OK/average recently, mediocre in the past. As I said, I'm using PCM almost exclusively these days. And while I have a few DACs that are DSD capable, I don't find DSD to be as convenient. And if I were you, I wouldn't take someone else's recommendation on what sounds best, including mine, no matter how many adjectives they use in their description. As far as measurements, RME has some very excellent devices out there, although they are not cheap.

 

An overall better-measuring DAC will be more transparent. I prefer not to make pronouncements on what someone will hear or not, but a DAC that adds a lot of distortion will be less transparent than one that doesn't, by definition. And within measurements I include my own DeltaWave null-type comparison that allows me to judge how close the reproduced musical waveform is to the original source. One of the main reasons I wrote DW was that I wanted an unbiased way to judge things like DACs, DDCs, amps, power supplies, software, and even cables. 

[beerandmusic]

24 minutes ago, pkane2001 said:

 I include my own DeltaWave null-type comparison that allows me to judge how close the reproduced musical waveform is to the original source. One of the main reasons I wrote DW was that I wanted an unbiased way to judge things like DACs, DDCs, amps, power supplies, software, and even cables. 

So what have you discovered using this DW software regarding what dacs came close to reproducing to the original source?

Also, any surprises in all your testing of anything?

 

[Miska]

2 hours ago, pkane2001 said:

And within measurements I include my own DeltaWave null-type comparison that allows me to judge how close the reproduced musical waveform is to the original source. One of the main reasons I wrote DW was that I wanted an unbiased way to judge things like DACs, DDCs, amps, power supplies, software, and even cables. 

 

Challenge is always to find a suitable capture device that has enough bandwidth and resolution and doesn't have analog + digital anti-alias filters that would complete otherwise incomplete reconstruction of the analog waveform...

 

So far I need to use three different measurement devices for complete set of measurements.

 

[pkane2001]

13 hours ago, Miska said:

 

Challenge is always to find a suitable capture device that has enough bandwidth and resolution and doesn't have analog + digital anti-alias filters that would complete otherwise incomplete reconstruction of the analog waveform...

 

So far I need to use three different measurement devices for complete set of measurements.

 

 

It's a challenge, but not a major one. There are excellent ADC devices out there, and some are inexpensive if you look at the Pro market. I rarely need one to go beyond 192kHz/24 bits, but when I do, I use a 100MHz DSO for that. 

[pkane2001]

15 hours ago, beerandmusic said:

So what have you discovered using this DW software regarding what dacs came close to reproducing to the original source?

Also, any surprises in all your testing?

 

 

I found that some inexpensive devices are often not very good, while others are really excellent. I've also found that pro devices are often a much better quality than some high-end audiophile ones, and at a lower price. Lately, I've been buying most audio equipment on the used pro market.

 

I found no obvious differences between audiophile and generic USB cables. I found very little difference between interconnects. I found some of the audiophile power-supplies to generate more noise than non-audiophile, stock versions. I found some of my older (high-end) DACs to be OK, but not anywhere near the performance of many modern, inexpensive DACs.

 

One finding that I didn't expect: I found many ground loops between devices. In my testing, ground loops are the norm. Rarely do I see a device that's fully immune to them, even with balanced interconnects, etc. It's really important to make sure these do not exist in your system before deciding to upgrade any of the components. Sometimes these manifest themselves in a low-level noise, sometimes rise to an audible hum. This is also an area where pro equipment seems to perform better.

 

 

[Miska]

2 hours ago, pkane2001 said:

It's a challenge, but not a major one. There are excellent ADC devices out there, and some are inexpensive if you look at the Pro market. I rarely need one to go beyond 192kHz/24 bits, but when I do, I use a 100MHz DSO for that. 

 

Yes, but I'm not talking about source files. I'm talking about checking DAC's reconstruction performance, and thus that needs enough bandwidth and dynamic range to capture all the output until it falls into the analog noise floor.

 

Remember that 192k 24-bit file contains a very long series of images until the zero-order-hold function falls into -144 dB at very high frequencies. When you want to reconstruct things, you need to remove all images and leave just the base band. Otherwise you are not getting the original analog waveform but something else.

 

I have 200 MHz DSO, but it has only 8-bit resolution, although it has 1M point FFT it still lacks a lot of dynamic range. So that's only the third instrument I use to do some basic checks about EMI/RFI output.

 

[pkane2001]

2 hours ago, Miska said:

 

Yes, but I'm not talking about source files. I'm talking about checking DAC's reconstruction performance, and thus that needs enough bandwidth and dynamic range to capture all the output until it falls into the analog noise floor.

 

Remember that 192k 24-bit file contains a very long series of images until the zero-order-hold function falls into -144 dB at very high frequencies. When you want to reconstruct things, you need to remove all images and leave just the base band. Otherwise you are not getting the original analog waveform but something else.

 

I have 200 MHz DSO, but it has only 8-bit resolution, although it has 1M point FFT it still lacks a lot of dynamic range. So that's only the third instrument I use to do some basic checks about EMI/RFI output.

 

 

My testing usually focuses on the audible range. I let DAC do what it would normally do to reproduce the source file, then do a null-compare of the recorded result to the original file. DeltaWave allows me to apply an arbitrary low pass filter, so I usually do that to limit the result of the comparison to, say, under 20kHz. 

[beerandmusic]

6 hours ago, pkane2001 said:

 

I found that some inexpensive devices are often not very good, while others are really excellent. I've also found that pro devices are often a much better quality than some high-end audiophile ones, and at a lower price. Lately, I've been buying most audio equipment on the used pro market.

 

I found no obvious differences between audiophile and generic USB cables. I found very little difference between interconnects. I found some of the audiophile power-supplies to generate more noise than non-audiophile, stock versions. I found some of my older (high-end) DACs to be OK, but not anywhere near the performance of many modern, inexpensive DACs.

 

One finding that I didn't expect: I found many ground loops between devices. In my testing, ground loops are the norm. Rarely do I see a device that's fully immune to them, even with balanced interconnects, etc. It's really important to make sure these do not exist in your system before deciding to upgrade any of the components. Sometimes these manifest themselves in a low-level noise, sometimes rise to an audible hum. This is also an area where pro equipment seems to perform better.

 

Thanks for all of this very valuable information.  Firstly....how does one ensure they have no ground loops between devices?   Do any inexpensive DACS do this well?  I don't ever notice any "hum" but maybe it is at such a high level that I don't hear it...but i still swear when i use anything (spdif, hdmi, network), they always sound better than usb, and what I struggle with, when there seems to be such competing opinions.  Also why would a usb thumb drive from my marantz on same ac circuit sound better.

[beerandmusic]

35 minutes ago, pkane2001 said:

 

My testing usually focuses on the audible range. I let DAC do what it would normally do to reproduce the source file, then do a null-compare of the recorded result to the original file. DeltaWave allows me to apply an arbitrary low pass filter, so I usually do that to limit the result of the comparison to, say, under 20kHz. 

I personally would rather have a solution that recreates as accurately as possible than one that just focuses on what is percieved as the "audible range" if it can be done relatively inexpensively. 

[beerandmusic]

6 hours ago, pkane2001 said:

 

 Lately, I've been buying most audio equipment on the used pro market.

Can you provide some examples models, especially if they isolate well?

 

Quote

I found no obvious differences between audiophile and generic USB cables. I found very little difference between interconnects.

 I am surprised there would be any difference in interconnects unless they were just "loose"? 

 

Quote

I found some of the audiophile power-supplies to generate more noise than non-audiophile, stock versions. I found some of my older (high-end) DACs to be OK, but not anywhere near the performance of many modern, inexpensive DACs.

What inexpensive modern dacs do you have first hand knowledge with that you are comfortable making this statement?

 

 

[pkane2001]

1 hour ago, beerandmusic said:

I personally would rather have a solution that recreates as accurately as possible than one that just focuses on what is percieved as the "audible range" if it can be done relatively inexpensively. 

 

With DeltaWave you decide what upper frequency is good enough. I know my hearing is diminished above 15kHz, so no reason for me to keep looking much above 20kHz.

 

1 hour ago, beerandmusic said:

Can you provide some examples models, especially if they isolate well?

 

Didn't keep track of this. I just found that I needed to fix ground loops nearly every time I tested by using separate power supplies (one being battery powered) or by using Toslink.

 

1 hour ago, beerandmusic said:

 I am surprised there would be any difference in interconnects unless they were just "loose"? 

 

Measurable differences well below -100dB, so nothing to get excited about. But yes, there were measurable differences.

 

1 hour ago, beerandmusic said:

What inexpensive modern dacs do you have first hand knowledge with that you are comfortable making this statement?

 

Nearly every one that's been measured on Gearslutz, since most posted a captured audio file that I could run through DeltaWave. At one point, I was planning to construct my own measurements list for all of these captures, so I downloaded and processed them all through DW. Had a recent disk crash and lost the files and the results. Maybe when I have a little more free time in the future, I'll try to do this again. Oh, and about 15 or so DACs that I have in my physical possession, from cheap SoundBlaster and Behringer interfaces to higher-end but still inexpensive Focusrite, UAD, and Apogee models.

 

[beerandmusic]

2 minutes ago, pkane2001 said:

Didn't keep track of this. I just found that I needed to fix ground loops nearly every time I tested by using separate power supplies (one being battery powered) or by using Toslink.

 

I routinely use toslink as it always sounds better than USB "to me", so perhaps i have ground loops (but i don't hear any hum or constant noise, that is typically suggested regarding them, but maybe it is above my hearing level but still affects the overall sound).

Since toslink isn't an option if i want to play native DSD files, i continue to look for different usb solutions.  When you say you use differeent power supplies, do you use them with the source or the dac? And are there any inexpensive power supplies that you have found that consistently improve this issue?

[beerandmusic]

PKANE>>

Quote

I found some of the audiophile power-supplies to generate more noise than non-audiophile, stock versions. I found some of my older (high-end) DACs to be OK, but not anywhere near the performance of many modern, inexpensive DACs.

 

2 hours ago, beerandmusic said:

What inexpensive modern dacs do you have first hand knowledge with that you are comfortable making this statement?

 

16 minutes ago, pkane2001 said:

Nearly every one that's been measured on Gearslutz, since most posted a captured audio file that I could run through DeltaWave. At one point, I was planning to construct my own measurements list for all of these captures, so I downloaded and processed them all through DW. Had a recent disk

crash and lost the files and the results. Maybe when I have a little more free time in the future, I'll try to do this again. Oh, and about 15 or so DACs that I have in my physical possession, from cheap SoundBlaster and Behringer interfaces to higher-end but still inexpensive Focusrite, UAD, and Apogee models.

 

 

WHen you use one of those models on Gearslutz, did you still have to use a "better" power supply?

[pkane2001]

33 minutes ago, beerandmusic said:

I routinely use toslink as it always sounds better than USB "to me", so perhaps i have ground loops (but i don't hear any hum or constant noise, that is typically suggested regarding them, but maybe it is above my hearing level but still affects the overall sound).

Since toslink isn't an option if i want to play native DSD files, i continue to look for different usb solutions.  When you say you use differeent power supplies, do you use them with the source or the dac? And are there any inexpensive power supplies that you have found that consistently improve this issue?

ground loops can be just a slightly elevated set of noise spikes, easy to see in a measurement but not obvious when listening. When measuring a device, I just make sure that the devices are not connected to the same power line. For example, use a laptop running off a battery while the DAC is running off AC power.

[pkane2001]

32 minutes ago, beerandmusic said:

PKANE>>

 

 

 

WHen you use one of those models on Gearslutz, did you still have to use a "better" power supply?

I have no control over how these were recorded, since these were done by others. Since a lot of these were recorded using an audio interface (the DAC and the ADC are both in the same unit) the chance of ground loop being formed between them is much smaller.

[Jud]

1 hour ago, pkane2001 said:

Had a recent disk crash and lost the files and the results.

 

Aaaargghh! (On your behalf.) 😕

[Jud]

9 hours ago, pkane2001 said:

I found many ground loops between devices. In my testing, ground loops are the norm. Rarely do I see a device that's fully immune to them, even with balanced interconnects, etc. It's really important to make sure these do not exist in your system before deciding to upgrade any of the components. Sometimes these manifest themselves in a low-level noise, sometimes rise to an audible hum. This is also an area where pro equipment seems to perform better.

 

I really think working on eliminating such sources of noise in *systems* that don't appear in individual components, cables, etc., on the test bench is a very fruitful pursuit.

[asdf1000]

On 6/13/2020 at 5:45 AM, Miska said:

Here you can see that within about 100 dB range, 1.4112M PCM through R2R section and DSD through the DSD section produce similar image levels on this DAC, so we can reach at least decent RedBook reconstruction.

 

 

Hi @Miska

 

Can you explain what you mean by the 100dB range because there's a lot of spikes in between -74dB and -102dB