Schiit Yggdrasil V2 upgrade Technical Measurements
Jul 1, 2018 at 7:32 AM Post #76 of 203
Fig.5 Schiit Yggdrasil 2 output of 1 kHz sine at -130 dBFS (from its balanced analog output), with no bandpass filtering.

While you do see some shape and periodicity that might suggest a sine wave, it's obviously not cleanly sinusoidal. And this is where we get to something I discussed in the previous post. If you want to measure something that's below the noise levels of both the DAC and analyzer, you can limit the passband to the stimulus we're analyzing. We know we're looking at a 1 kHz sine signal, so setting an elliptic high-pass filter at 1 kHz, and an elliptic low-pass filter at 1 kHz, we're going to be very tightly analyzing essentially just the 1 kHz stimulus, and avoiding the noise from the rest of the audioband. Looking at the scope view after filtering, this is what a -130 dBFS 1 kHz sine looks like from the Yggdrasil 2's balanced analog outputs (Fig.6):

The lovely, perfectly shaped sine wave shown here is an illusion. Nobody knows and can show how that signal looks like, no matter what DAC is used, because it is covered too deeply in noise. If you apply a steep and narrow bandpass filter to a signal - whatever signal - it will always look like a sine wave having the frequency of the bandpass center. Feed it triangle, sawtooth, square - doesn't matter. The output of the DAC might have steps, stairs, other irregularities (from theory it definitely will have those) - but there is no way to show it as waveform. The only way to get a grasp of its pureness is doing a very deep THD analysis via FFT. But at -130 dBFS even that usually fails, as the noise floor in the FFT will not go lower than around -160 dBFS. So anything better than -30 dB THD is covered in noise again.
 
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Jul 1, 2018 at 8:17 AM Post #77 of 203
Schitt standing up and telling people if they have an issue to contact info@schitt.com is laudable.

Having a guy like this other guy supposedly measuring "objectively" yet including glittering adjectives and accusations is not.

and this other guy is indeed NOT the second coming of Dale Earnhart!

Alex

Note: Schitt has a 5 year warranty...Why would a vendor have a warranty 5 times the normal 1year warranty if they were going to produce crap?

and to those many, many owners of this dac who tout its greatness over and over are not hearing this stuff,,,wonder why?

and seeing how this dac is on back order tells me more people are buying this dac for a good reason.

and its not from an "objective" set of measurements from a questionable site...
 
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Jul 1, 2018 at 10:13 AM Post #78 of 203
It looks like Amir has a major issue with Schiit, or he dug himself so deep in a hole and he doesn't have the balls to admit he messed up. Then you have the tribe mentality of ASR and Schiit supporters bickering over "charts". The unfortunate outcome is that Schiit has probably lost some business because the average internet audiophile cannot critically think and will take ASR as gospel.
 
Jul 1, 2018 at 10:26 AM Post #79 of 203
Its par for the course.

There are always those that will just blindly follow in tribe mode.
These are not even close to being average audiophiles IMO.

Then there are those that actually buy and use stuff and make there own conclusions without having to sort thru
charts and graphs.

Most of those folks just want to be on a winning side regardless of the facts.

They just want another piece of stuff to put in their tag line...

Such a waste of time...
Alex
 
Jul 1, 2018 at 10:56 AM Post #80 of 203
The only way to get a grasp of its pureness is doing a very deep THD analysis via FFT. But at -130 dBFS even that usually fails, as the noise floor in the FFT will not go lower than around -160 dBFS.

There's no theoretical limit to the depth of the 'noise floor' with an FFT. That's because its a function of the bin bandwidth and with a long enough (in time) waveform to sample, and enough memory to store it in, the limit will be the size of the FFT algorithm. Probably the AP has some limit on the FFT size though.
 
Jul 1, 2018 at 11:40 AM Post #81 of 203
The lovely, perfectly shaped sine wave shown here is an illusion...

The point of that entire post is to show that we will often run into a DAC's audioband noise floor before we reach the limits of its ability to decode linearly at the lowest dBFS levels. So if we want to observe linearity below the noise level across the audioband bandwidth, we have to use a bandpass filter.

...Nobody knows and can show how that signal looks like, no matter what DAC is used, because it is covered too deeply in noise...

Actually in those two figures (copied below, Fig.1 and Fig.2), we do know what the 1 kHz stimulus looks like to the analyzer, first with the noise from the audioband present...


Fig.1 Schiit Yggdrasil 2 output of 1 kHz sine at -130 dBFS (from its balanced analog output), with no bandpass filtering.

...and without all the noise from the audioband present (by using a bandpass filter, in this case elliptic filters on either side of the 1 kHz stimlus)...


Fig.2 Schiit Yggdrasil 2 output of 1 kHz sine at -130 dBFS (from its balanced analog output), with 1 kHz elliptic high-pass filter and 1 kHz elliptic low-pass filter applied.

While it does take bandpass filtering to see the waveform properly, it is coming from the DAC's outputs, and thus it does have to be decoding it at that dBFS level for this to show.

...If you apply a steep and narrow bandpass filter to a signal - whatever signal - it will always look like a sine wave having the frequency of the bandpass center. Feed it triangle, sawtooth, square - doesn't matter...

The signal has to be there in the first place. If at a given dBFS level the DAC is not outputting the waveform then any amount of filtering isn't going to unveil (or make clearer) something that doesn't exist.

...Feed it triangle, sawtooth, square - doesn't matter. The output of the DAC might have steps, stairs, other irregularities (from theory it definitely will have those) - but there is no way to show it as waveform...

I think you're referring to the sinc interpolation that happens by default in APx for time domain measurements. It can be switched off, but is on by default. Here's the DAC outputting a 1 kHz signal at 0 dBFS (sample rate 44.1 kHz, bandwidth-limited by high-pass elliptic filter at 1 kHz and low-pass elliptic filter at 1 kHz), with the interpolation option visible (bottom-left):

Capture-scope-without-interpolation-(hipass-ell-1k_lopass-ell-1k_44.1-kHz_1-kHz-0dBFS).JPG

Fig.3 Schiit Yggdrasil 2 outputting a 1 kHz signal at 0 dBFS (sample rate 44.1 kHz, bandwidth-limited by high-pass elliptic filter at 1 kHz and low-pass elliptic filter a 1 kHz), with interpolation switched off (and the interpolation option showing bottom-left)

And if you want to see the waveform without interpolation at -130 dBFS:

Scope-without-interpolation-(hipass-ell-1k_lopass-ell-1k_44.jpg

Fig.4 Schiit Yggdrasil 2 outputting a 1 kHz signal at -130 dBFS (sample rate 44.1 kHz, bandwidth-limited by high-pass elliptic filter at 1 kHz and low-pass elliptic filter a 1 kHz), with interpolation switched off

(At this low level, the sine wave is not particularly stable, but does maintain its sinusoidal shape.)

...The only way to get a grasp of its pureness is doing a very deep THD analysis via FFT. But at -130 dBFS even that usually fails, as the noise floor in the FFT will not go lower than around -160 dBFS. So anything better than -30 dB THD is covered in noise again.

That's what I did in the post you quoted: Nested FFT measurements. Beneath Fig.2 and Fig.3 in that post, you'll see links to view those same plots with the Y-axis zoomed out.

If I'm misinterpreting any of your comments, let me know.
 

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Jul 1, 2018 at 12:13 PM Post #82 of 203
I think you're referring to the sinc interpolation that happens by default in APx for time domain measurements. It can be switched off, but is on by default. Here's the DAC outputting a 1 kHz signal at 0 dBFS (sample rate 44.1 kHz, bandwidth-limited by high-pass elliptic filter at 1 kHz and low-pass elliptic filter at 1 kHz), with the interpolation option visible (bottom-left):


Fig.3 Schiit Yggdrasil 2 outputting a 1 kHz signal at 0 dBFS (sample rate 44.1 kHz, bandwidth-limited by high-pass elliptic filter at 1 kHz and low-pass elliptic filter a 1 kHz), with interpolation switched off (and the interpolation option showing bottom-left)

And if you want to see the waveform without interpolation at -130 dBFS:


Fig.4 Schiit Yggdrasil 2 outputting a 1 kHz signal at -130 dBFS (sample rate 44.1 kHz, bandwidth-limited by high-pass elliptic filter at 1 kHz and low-pass elliptic filter a 1 kHz), with interpolation switched off

(At this low level, the sine wave is not particularly stable, but does maintain its sinusoidal shape.)
Oooh... can you show that same measurement for a delta sigma DAC? Would it look similar because the steps are just the result of turning off the sinc interpolation, or would it indeed be shaped more irregularly?
 
Jul 1, 2018 at 8:34 PM Post #83 of 203
Actually in those two figures (copied below, Fig.1 and Fig.2), we do know what the 1 kHz stimulus looks like to the analyzer, first with the noise from the audioband present...

While it does take bandpass filtering to see the waveform properly, it is coming from the DAC's outputs, and thus it does have to be decoding it at that dBFS level for this to show.

You missed my point about filtering and the result on the signal. This is not about Sinc, it is about basics of physics/electronics laws. Just try what I wrote about: output a triangle, square whatever signal from the AP, then view it with both these extreme narrow and steep filters active - the waveform is turned into a pure sine wave. Therefore whenever using such an extreme bandpass filter the result will look like a perfect sine. Which then means no one knows how the signal at -130 dBFS really looks like.

@Sapientiam: you are right, large FFT 1M up and lots of averaging will bring the FFT noise floor down. I never tried it because it takes too much time.
 
Jul 1, 2018 at 9:05 PM Post #84 of 203
I am just casually following this circus....:ksc75smile:

So are other "sites" slamming the Yggdrasil or just ASR?
 
Jul 1, 2018 at 9:33 PM Post #85 of 203
You missed my point about filtering and the result on the signal. This is not about Sinc, it is about basics of physics/electronics laws. Just try what I wrote about: output a triangle, square whatever signal from the AP, then view it with both these extreme narrow and steep filters active - the waveform is turned into a pure sine wave. Therefore whenever using such an extreme bandpass filter the result will look like a perfect sine. Which then means no one knows how the signal at -130 dBFS really looks like...

Ah, I did misunderstand your point the first time (but get it now).

I showed both plots, one without the bandwidth limiting and one with. I understand that if I use a square or triangle with such a narrow filter I'll get a sine on the scope -- in either case, I know under the test circumstances, I'm outputting neither (or any other waveform but sine as a stimulus). As I understand it, even that narrow a filter (high-pass elliptic at 1 kHz, low-pass elliptic at 1 khz) is not going to draw from the noise floor the 1 kHz periodicity that even the non-bandwidth-limited scope view showed at the level it was showing. (And, again, that post did include accompanying FFT spectrum plots that weren't bandwidth limited.)

Again, if I'm getting something wrong here, let me know.
 
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Jul 1, 2018 at 10:41 PM Post #86 of 203
You missed my point about filtering and the result on the signal. This is not about Sinc, it is about basics of physics/electronics laws. Just try what I wrote about: output a triangle, square whatever signal from the AP, then view it with both these extreme narrow and steep filters active - the waveform is turned into a pure sine wave. Therefore whenever using such an extreme bandpass filter the result will look like a perfect sine. Which then means no one knows how the signal at -130 dBFS really looks like.
But we do have a good idea of the unfiltered time domain behavior at -120 dBFS.

Here is the yggdrasil A2 -120 dBFS unfiltered time domain sine response with FFT superimposed from dScope:

20180701 yggdrasil 1KHz sine -120 dBFS t2.png



Now here is the yggdrasil A2 -120 dBFS SQUARE WAVE response with FFT superimposed from dScope:

20180701 yggdrasil 1KHz sqr wave -120 dBFS t2.png


To put these levels into perspective, 0 dBFS is 2 Vrms so -120 dBFS is 2 uVrms (2 millionths of a volt.)
20 KHz bandwidth residual noise of a 50 ohm resistor is on the order of 127 nanovolts.
 
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Jul 2, 2018 at 9:45 AM Post #87 of 203
like having to come to the table with no fewer than his years of (no doubt impressive) experience,

Jude;

Impressive is very possibly a major overstatement. He trys to be impressive and has conned his way all these years, but let's be real here.

Started as an entry-level programmer. Well spoken sounds like he actually knows something, this got him a management position. Moving forward, manager at MS, took credit for others work, but no actual hands-on experience of any type. Left MS (he claims early retirement) ok hmm. Questionable ventures after that.

Bottom line, lots of talk, but no real action or verifiable hands-on experience of any type. He is an internet showman, the Audio Vigilante lookng to save the world one DAC at a time!

He claims he and his band of merry men are uncovering the dishonesty in the audio world. If you look at the manufacturers he picks on, there is a pattern.

Bob
 
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Jul 2, 2018 at 10:16 AM Post #88 of 203
NwAvGuy... North West Audio/Video Guy... Microsoft... Seattle. Audio/Video. Checks out.
 
Jul 2, 2018 at 10:54 AM Post #89 of 203
Guys, let's keep it on topic.

While anything I know about his background and experience has come only from what he's posted about himself, taken at his word it is an impressive resume with impressive experience.

Let's try to keep this discussion primarily about the DAC and related measurements.
 
Jul 2, 2018 at 11:11 AM Post #90 of 203
Guys, let's keep it on topic.

While anything I know about his background and experience has come only from what he's posted about himself, taken at his word it is an impressive resume with impressive experience.

Let's try to keep this discussion primarily about the DAC and related measurements.
I am sorry. You are absolutly correct. And you are a good guy, and so are Jason and Mike! :)

And yes we should take people at their word. Btw: I forgot to tell you that I am actually the queen of England!

queen-elizabeth2.jpg

imgres
 
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