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Worlds Greatest DAC and what it does differently


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On 6/10/2020 at 9:31 PM, 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.

 

Given that the other DAC here is running 16-bit R2R at 192k sample rate, you don't need to zoom much to see stair steps on it. Or in frequency domain to see images at multiples of 192k sampling rate...

 

Vastly different, to a well performing DAC, the difference in image levels is in several tens of dB, even close to 100 dB.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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On 6/11/2020 at 7:33 AM, beerandmusic said:

Yes, he was...i specifically stated in the thread, "differences within the audible spectrum" and i repeated it many times.

 

I'm pretty sure even in THD frequency distribution figure within audible spectrum differences are well over 10 dB. And then when you take into account things like different digital and analog filter roll-offs and differences in phase responses within audible spectrum.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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On 6/11/2020 at 7:16 PM, beerandmusic said:

edit to add:: since you believe if everything was perfect that 44.1khz should be sufficient to capture the audible spectrum, I personally think that 96K would likely be more ideal as 44.1K is very close to our boundaries and that 96K "may" be a rudimentary step that would leave no room for argument, and plus it is a multiple of 48k which I understand is more ideal for video, that 96K "may" be a "sweet spot" for both recording and reconstruction.

 

96k is not enough for proper reconstruction with analog filters. Even very early CD players from Philips used 4x upsampling filters to play at 176.4k rate. And these are still far from perfect.

 

96k may be OK'ish for delivery format, but not for running conversion section. These are two different things.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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2 minutes ago, beerandmusic said:

3) would there be any measurable differences between 2 different competent dacs one being pcm 192K and the other upsampled to quad rate dsd at the "analog out"

 

Of course yes. If you look close enough, you can find differences between two DACs of same model, thanks to component tolerances.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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2 minutes ago, beerandmusic said:

ok...lets go with PCM 192K then?

 

As I said earlier, when you get PCM sampling rate at about 1.5 MHz, then R2R ladders with typical analog section begin to look decent. But that is not easy thing to get working properly in first place due to settling time problems at high precision. But luckily there are digital domain tricks that you can do to help the DAC perform better.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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3 hours ago, beerandmusic said:

Ok this brings me to another question...can HQP play directly to a DLNA renderer without NAA? (not sure I am using the right terms...i know i can play music from DLNA music server on qnap from jriver to my marantz streamer...can i play from hqplayer to marantz streamer?

 

No, but HQPlayer Embedded can operate as UPnP Renderer. (DLNA is sort of obsolete specification for high quality audio, it just specifies bunch of mandatory and optional formats, mandatory ones being such as 128 kbps MP3)

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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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.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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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.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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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.

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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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.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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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.

 

Signalyst - Developer of HQPlayer

Pulse & Fidelity - Software Defined Amplifiers

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