USB audio cracked... finally!

[k-man]

1 hour ago, Speed Racer said:

 

Seriously! Any review by manishandher of any Schiit product is suspect and I would be unable to trust it. 

Way too cynical Speedy ! A bit of healthy respect between the 2, they have even named Mani for one of their components.

[Dev]

1 hour ago, k-man said:

Way too cynical Speedy ! A bit of healthy respect between the 2, they have even named Mani for one of their components.

 

A safe bet for a phono pre but I suspect they would ever dare to name it after a DAC

[opus101]

6 hours ago, manisandher said:

 

I've never understood why people think transformers prevent noise from passing through them. They prevent DC, for sure, and are certainly bandwidth limited. But in this case, they must pass (edit - really need to get my M and k sorted out!) 500MHz or so, so any noise under (edit) 500MHz will get through. If it didn't, the USB signal wouldn't either.

 

Transformers are good for rejecting common-mode noise (they have good CMRR). They must pass 500MHz (or whatever the bandwidth) as a differential-mode (often called 'normal mode') signal but when there's equal noise on both signal lines (seeing we're talking differential transmission) then the trafo's going to reject it.

Of course in practice the noise is never quite equal on the two lines so some noise is going to get through as a normal-mode signal.

[PeterSt]

7 hours ago, jabbr said:

 In any case the DIYINHK version is $40 but doesn't have the isolation.

 

Then you are looking at the wrong DIYINHK version. 

The one costing $109 sure has isolation. And much more than the Schiit offers. Like 1024 DSD support. Hahaha. Oops.

 

But it is still USB. Who wants that. 

[Speed Racer]

10 minutes ago, PeterSt said:

 

Then you are looking at the wrong DIYINHK version. 

The one costing $109 sure has isolation. And much more than the Schiit offers. Like 1024 DSD support. Hahaha. Oops.

 

But it is still USB. Who wants that. 

 

You might want to reserve criticism for a product until you have a chance to hear it in action......

[marce]

14 hours ago, mmerrill99 said:

As I said to Jabbr, I would suggest you read the links & correct your knowledge on this - you seem to have many contradictory views to what Ritchie says.

 

No, it's not just about PCB traces as I pointed out to jabbr

Cables are best twisted pair, these notes are for PCBs mainly, where the close coupling can not always be maintained. Point most PCBs follow the defined rules for a differential interfaec. I.e. diff pair impedance.

[marce]

13 hours ago, mmerrill99 said:

@The Computer Audiophile

What I actually said was " read the links & correct your knowledge on this"

 

I specifically gave links to quality articles by known experts in the field which answers the points raised in many of the posts which followed. What I meant by " read the links & correct your knowledge on this" was meant to mean just that & specifically to avoid the boring esoteric stuff being posted when there was no need - it's already answered in the articles.

 

I also believe that there's a bit of imbalance in your view of what's personal:

 

 

 

 

You should have explained yourself better...

I wonder if anyone creating these wonderful products has ever thought of using Signal Integrity software, you'd save a lot of time and hassle...

[marce]

11 hours ago, Speed Racer said:

 

I still don't get this. Look here:

 

 

How does the noise get past the magnetic transformer?

Noise especially high frequency couples capacitivley.

 

[marce]

11 hours ago, jabbr said:

 

There's also GMR which really is very similar to transformer: https://www.nve.com/Downloads/galv.pdf

There is still some capacitive coupling through many of these devices especially the Adum types.

[Superdad]

12 hours ago, manisandher said:

 

From the Schiit website:

 

Suggests that nothing before the Gen 5 will make a difference. Might buy a new Schiit DAC with Gen 5 installed just to find out. Will obviously report my findings...

 

To be clear--and I am not knocking that they are being cool and doing isolation without using traditional digital isolators (even the best of which add some jitter)--the isolation that Schitt is doing is, as with every** other DAC that has isolators, their transformers come AFTER the USB PHY/processor.  

 

So to the extent that signal integrity, ground plane noise, and packet data noise affects other DACs with GI (on the I2S lines after the USB processor), it likely will for the new Schiit input board.  It will likely still sound great, but just as with others (Chord, exaSound, Berkeley Alpha, and lots of other DACs with isolation after their USB processor), USB cables and other modifiers of signal integrity (aka all the "decrapifiers"/"regenerators"--yes we all know I am a purveyor) are still likely to be heard.

 

(** the asterisks in the first paragraph above by "every" are a nod to PeterSt. as he is putting his Phisolator (Silanna chip) isolation ahead of his USB processor.  And you will see others doing so--also with the Silanna chip as used in the ISO REGEN--soon.  The newly announced  Auralic DACs for sure.)

 

Of course the many users' ears will tell soon.  And I am for any and all advances in USB, Ethernet, and future computer audio interfaces.  Just wanting to keep things in perspective.  

 

[Jud]

1 hour ago, marce said:

There is still some capacitive coupling through many of these devices especially the Adum types.

 

Yes, I love the marketing copy that talks about “perfect” immunity or isolation.  Perfect is quite hard.

 

Very very good can be done with care and a little expenditure, though.

[manisandher]

3 hours ago, PeterSt said:

But it is still USB. Who wants that. 

 

 

Hey Peter, what exactly did you mean by this?

 

Mani.

[seeteeyou]

What else could we add? Not much?

 

https://www.computeraudiophile.com/forums/topic/28637-holo-audio-spring-dac-r2r-dsd512/?page=12#comment-627406

On 2/4/2017 at 11:10 AM, GUTB said:

 

SBAF is a cult / insular ego bottom feeder site. The general audio knowledge of CA is significantly higher. Marvey, the owner of the site, also reviewed the Spring and found it to be slightly inferior....to the Gunjir Multibit.

 

This particular one seemed to be the ćùļţ leader, who knows?

 

https://www.computeraudiophile.com/profile/25602-marvey/

Quote

JOINED
December 12, 2015

 

LAST VISITED
December 12, 2015

 

[Jud]

2 hours ago, manisandher said:

 

 

Hey Peter, what exactly did you mean by this?

 

Mani.

 

Heh - the discussion of USB frequently reminds me of what Winston Churchill said about democracy:

 

Quote

Indeed it has been said that democ­ra­cy is the worst form of Gov­ern­ment except for all those oth­er forms that have been tried from time to time.…

 

USB has the worst problems of any audio interface, except for all the others that have been tried commercially so far.   

 

This isn't to say better interfaces aren't to come, just that we should recall SPDIF, optical, and I2S have their own limitations and disadvantages.  AES/EBU may have its own problems as well, but I'm not sufficiently familiar with it to know about them.  (Can it be run async, with the controlling clock in the DAC?)  Ethernet is promising, but as we've been discussing, its galvanic isolation isn't a panacea; and thus far we don't have an interface available to consumers that will do the resolutions some folks like to run.

[manisandher]

12 minutes ago, Jud said:

AES/EBU may have its own problems as well, but I'm not sufficiently familiar with it to know about them.  (Can it be run async, with the controlling clock in the DAC?)

 

Hey Jud, I used AES/EBU for a long time, using a Weiss AFI1 (firewire) to interface my Pacific Microsonics Model Two to the audio PC. Yes you can have the controlling clock in the DAC - you need to have a separate clock line and set the DAC to 'master' and the interface (or the transport, or whatever else) to 'slave'. It worked pretty well. The biggest issue for me was the lack of proper impedance matching on the 110 Ohm cables (only 50/75 Ohm BNC seems to be capable of providing this effectively), so all AES cables sounded different. Even different lengths of the same AES cable sounded different, as did varying the AES signal voltage through the cable. I'm pretty certain I documented all this right here on CA - the threads are probably 6-7 years old now.

 

Mani.

[marce]

Its a basic USB interface, use some signal integrity software, play about... Me thinks some audiophiles see to many gremlins with any digital interface. I see lots of comments about signal integrity but don't see no evidence of signal integrity verification.

Isolation and noise, again how much noise is there, what frequency, etc basic EMC engineering that most products have to conform too, it would be interesting to get some info about how much noise is being put out by a selection of source devices (PC's, bespoke severs etc.) and how and if any devices are stopping it and whether they are adding their own problems.

All this is pretty simple stuff for something based on a USB interface (or even SPDIF) compared to some of the digital interfaces around.

[marce]

3 minutes ago, manisandher said:

 

Hey Jud, I used AES/EBU for a long time, using a Weiss AFI1 (firewire) to interface my Pacific Microsonics Model Two to the audio PC. Yes you can have the controlling clock in the DAC - you need to have a separate clock line and set the DAC to 'master' and the interface (or the transport, or whatever else) to 'slave'. It worked pretty well. The biggest issue for me was the lack of proper impedance matching on the 110 Ohm cables (only 50/75 Ohm BNC seems to be capable of providing this effectively), so all AES cables sounded different. Even different lengths of the same AES cable sounded different, as did varying the AES signal voltage through the cable. I'm pretty certain I documented all this right here on CA - the threads are probably 6-7 years old now.

 

Mani.

With measurements?

[PeterSt]

1 minute ago, marce said:

All this is pretty simple stuff for something based on a USB interface (or even SPDIF) compared to some of the digital interfaces around.

 

That is what you would like (to think). Any complex interface (you implicitly refer to) is error corrected. Also, such an interface does not suffer from jitter really, assumed it carries low enough jitter not to produce errors. Think telephone conversations (ok, they s*ck to begin with).

Audio (as in audiophile terminology) is a totally different world for uncountable reasons. The most complex of all, perhaps.

[manisandher]

23 minutes ago, marce said:

With measurements?

 

Me? No. I observed the differences in sound, as I described. I then went looking for what might be causing them and learned a lot from Pat over at AR-T, an RF engineer who has the necessary equipment to test these things.

 

Edit: This is the sort of stuff he likes to do:

 

Output return loss from his Legato USB-to-spdif converter:

Output return loss from an unnamed competitor's product:

Output return loss from another unnamed competitor's product:

Mani.

[Jud]

2 minutes ago, PeterSt said:

Audio (as in audiophile terminology) is a totally different world for uncountable reasons.

 

I know they are uncountable for you, as long as you've been in this (anyone looking at the number of controls in the XXHighEnd software interface can see that), but I have a feeling marce might like you to count some reasons. 

 

I'll go first: One XXHighEnd control helps to determine how much of the audio file is preloaded into memory before being sent along for playback.  Of course I wondered how this could affect the sound.  I then coincidentally ran into a thread on another audio site (Computer Audio Asylum) where John Swenson and Gordon Rankin explained how this could occur.  So effects can come from surprising angles.

[marce]

18 minutes ago, PeterSt said:

 

That is what you would like (to think). Any complex interface (you implicitly refer to) is error corrected. Also, such an interface does not suffer from jitter really, assumed it carries low enough jitter not to produce errors. Think telephone conversations (ok, they s*ck to begin with).

Audio (as in audiophile terminology) is a totally different world for uncountable reasons. The most complex of all, perhaps.

No its moving digital data from a to b, complex no not really, low speed by today's standards, jitter and USB!!! the DAC has ultimate timing control. Sorry whether its moving data for wave front sensors or digital audio its about getting the digital information from a to b intact and readable. We use signal integrity software (as well as physical checking of waveforms) and only for the hard interfaces, if USB audio is that hard why do I see NO evidence of proper signal integrity engineering...

[jabbr]

7 hours ago, PeterSt said:

 

Then you are looking at the wrong DIYINHK version. 

The one costing $109 sure has isolation. And much more than the Schiit offers. Like 1024 DSD support. Hahaha. Oops.

 

But it is still USB. Who wants that. 

 

Yes that's correct. But of course $60 for a bare board translates to ?3x ?10x to the end customer?

 

DIHINHK has very good prices.

 

Ha, USB, well maybe if you've figured out the issues, then Ethernet won't be better ... although Fiber does get rid of the capacitive coupling issues to some extent

 

[marce]

18 minutes ago, manisandher said:

 

Me? No. I observed the differences in sound, as I described. I then went looking for what might be causing them and learned a lot from Pat over at AR-T, an RF engineer who has the necessary equipment to test these things.

 

Mani.

Thanks.

 

[manisandher]

2 minutes ago, marce said:

Thanks.

 

Probably didn't get the graphs up quickly enough...

 

Very interesting stuff!

 

Mani.

[PeterSt]

16 minutes ago, marce said:

Its a basic USB interface, use some signal integrity software, play about... Me thinks some audiophiles see to many gremlins with any digital interface

 

OK, next attempt. 

 

So we have the subject of this topic - the cable. If you are certain that USB cables don't make a difference for audio, then I think it is better to stop reading.

 

Then we have my personal idea that at this moment (and for me / Phasure) the most in audio can be advanced by means of USB improvements. You may call it tweaks, but those sound only different. So improvements is key.

Of course it is (or should be) moot to you that this is my thinking. Fact is that since I think like this, the one after the other real improvement pops up (ask the customers).

 

Data integrity ? no. For many maybe yes, but not for me as the USB errors are shown in real time. They should not be there and they are not there. And *if* they are there you will hear clicks or pops or scratches, up to silence when things really fail. Btw, more USB cables fail on this than not.

Sadly, we can also say : Data integrity ? Yes. But this is more of the voodoo kind and the hope that less jitter in USB data sounds better or technical is better for the further work out of the D/A process. You may have seen me write about that I am not certain about this. Still the Phasure NOS1a/G3 too has a "femto clock" for its USB interface. Does it help ? yes, together with the remaining upgraded parts it does. On its own ? I don't think so, or it is inaudible.

 

Higher bandwidth USB ? well, this is a very indirect one, with the notice that this is about the upsampling possibility the DAC can digest (mind you, which thus the computer can spit out). Not so important ? ... only know that the filtering (which is that upsampling) "makes" the sound.

 

I'll stop for now but notice that this is all interface related only and that our interface is USB.