Why is SPDIF better than USB? - Page 2

Originally Posted by baglunch 

... is it danceable?

to answer your OP question...most USB inputs run off a 16/48 max PCM270x chip that sounds craptastic compared to any serious S/PDIF interface.

It could be done pretty easily. In some situations I2S instead of spdif is possible as well. But an external reclocker like the hiface has the benefit of swappability. Also it can be plugged into a usb port, then only have an spdif cable, but make sure to support the hiface because it is not very healthy for the usb port to have too much weight leveraged against it.

Then you have to ask, what's more important, convenience or the theoretical benefits of less wiring and I2S instead of usb or spdif? Maybe the way reclockers are now strike a good compromise between the practical and the ideal. Still I think hard-drive based transports can minimize the issue of long distance digital transmission, but I think creating such devices is outside the expertise of most audiophile companies. If I can find a typical hard drive based transport with built-in lcd screen, good software and price, I would mod it to be audiophile grade and put it right next to my dac for I2S.

Not so long ago I used to wake up in the middle of the night in sweat after having nightmare about my PC not outputting bit-perfect and jitter corrupting signal down my optical cable.

To the OP: why don't YOU just listen to both and decide for YOURSELF what sound YOU like most.

Spending too much time on Head-fi feels like being in the Matrix. You need to decide NOW if you want to take  the red pill or the blue pill? 

What a Novel idea!

Using your ears to decide if something sounds good rather than reading posts, measurements, and specs.

Nah, thats just too strange....it will never catch on...

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Originally Posted by Dynobot 

What a Novel idea!

 

Using your ears to decide if something sounds good rather than reading posts, measurements, and specs.

 

Nah, thats just too strange....it will never catch on...

 

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Originally Posted by plonter 

It's just tad obvious though.... (...just saying).

Peete.

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Originally Posted by leeperry 

 

 

using toslink? I also did some real world experiments: my Firestone Bravo S/PDIF transporter uses a WM8804 chip to reclock S/PDIF to 50ps. When feeding my Firestone Spitfire DAC, a 15cm homebrew 75Ω tinned copped coax cable sounded noticeably tighter and clearer than this 65 strands glass toslink 6ft cable. Both were running off linear regulated PSU's and the Bravo is using a Tenor chip, which I filter w/ an ADUM4160 dongle.

 

Toslink requires 2 light conversions...m2tech said that toslink was unmanageable jitter-wise when releasing their hiface, it's in their FAQ. Very often you can see 700/800ps jitter mesurements for toslink, but even the best S/PDIF receivers(such as DIR9001) only provide a 50ps clock recovery.

Toslink. I would rather not get into a jittter debate here. All I can say is that with my system and rapid swiitching *I* could not hear differences between the two inputs playing the same tracks time-aligned. Anyone with a 2009 Zero and two computers could try this. I guess if this is an interesting enough question I could record the analog outputs and compare them, I'll have a go next week. 

Originally Posted by nick_charles 

Toslink. I would rather not get into a jittter debate here. All I can say is that with my system and rapid switching *I* could not hear differences between the two inputs

I've got no problem believing that you would not hear a difference between a plastic toslink cable through a CS8416 S/PDIF receiver and a PCM2704 USB input. Especially when the Zero is using OPA2604 opamps(if you didn't swap them).

Jitter is the plague of digital audio, and the reason(together w/ the galvanic isolation) why ppl prefer coax over USB or toslink....now the OP can buy the best gear he can afford, and hear it for himself

Quote:

Originally Posted by leeperry 

 

I've got no problem believing that you would not hear a difference between a plastic toslink cable through a CS8416 S/PDIF receiver and a PCM2704 USB input. Especially when the Zero is using OPA2604 opamps(if you didn't swap them).

 

Jitter is the plague of digital audio, and the reason(together w/ the galvanic isolation) why ppl prefer coax over USB or toslink....now the OP can buy the best gear he can afford, and hear it for himself

My Zero uses the 627 opamp - I paid extra for it

I do have an older 2604 zero as well, but it does not have USB...

My opinion about the importance of jitter is not the same as yours, but I'm not getting drawn.

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Originally Posted by leeperry 

 

Did you compare a low jitter short coax against that crummy PCM2704 USB controller? I'm sure you could source an Hiface from a seller w/ a return policy. I don't know how good this would sound, but definitely better than plastic toslink or PCM2704. This PDF about WM8804 discusses the audio jitter audibility, and was presented at an AES convention: http://www.wolfsonmicro.com/documents/uploads/misc/en/A_high_performance_SPDIF_receiver_Oct_2006.pdf

 

The paper that your pdf references in section 3  (Audibility of Jitter) is Benjamiin and Gannon 98 who place jitter audibility in the several 10s of nanoseconds, it is the only reference to empirical testing of jitter audibility in the paper. Whatever you think about my DAC's USB receiver it won't make jitter any more audible.

Originally Posted by nick_charles 

Whatever you think about my DAC's USB receiver it won't make jitter any more audible.

So I take it that you have never tried a low jitter coax transport...because its improvement will be inaudible anyway, right? So all the ppl raving about a clearer and more focused sound in the Hiface thread are defenseless victims of teh evil placebo?

You ran a shootout of audio cables, maybe trying a low jitter coax transport could shed some lights too...It's highly unlikely that, using some transparent-enough headphones, you wouldn't hear a diff. between the Hiface and the USB/toslink inputs of your Zero DAC. Just saying

Quote:

Originally Posted by leeperry 

 

 

[1] So I take it that you have never tried a low jitter coax transport...because its improvement will be inaudible anyway, right? So all the ppl raving about a clearer and more focused sound in the Hiface thread are defenseless victims of teh evil placebo?

 

[2]You ran a shootout of audio cables, maybe trying a low jitter coax transport could shed some lights too...It's highly unlikely that, using some transparent-enough headphones, you wouldn't hear a diff. between the Hiface and the USB/toslink inputs of your Zero DAC. Just saying

1. I have two Coax transports CD players (a 1990s type and a 2000s type) , I do not know what their jitter figures are, controlled tests run by serious researchers (in two continents)  and not amateurs like myself suggest that the likely jitter levels in any of my systems is not a problem  , so yes there is no reason to expect the improvement to be audible.

Have any of these ravers tested this in anything like a controlled manner, i.e direct time-aligned and level matched comparisons ? or was there a gap of minutes, hours or days between the auditions. A more meaningful test however would be to record the signals from the two systems and compare them digitally , removing expectation problems. It is of course possible for a thing to be faulty, this could be more reliably shown with numerical comparisons against a reference. I've done this kind of test it is far more telling than simple A/Bs 

2. I am still out over $100 on cables bought and resold at a loss or not resold (who wants to buy a cable when the seller tells you openly that they think it will make zero difference, I still have the silver cable) . You want to lend me a Hiface (as a matter of ethics I will not buy something knowing that I will return it) I'll happily run the tests you suggest and also measure the outputs which would be much more rigorous than my hearing as you could argue I did not want to hear the differences.

But let's make this more interesting. How about this. I will buy a Hiface with RCA Coax and test it against the raw USB using a 24/96 ADC on the analog outputs. I'll publish the graphs, the test files and the raw data. If there is a significant difference in the FR (not just a level difference overall, I already have one of those), (the gizmo is doing a conversion, one wants to make sure it isn't cheating) or timing variation AND the Hiface/Coax output is more accurate than the USB vs the reference I will keep the Hiface. If not (there is no significant difference or the Hiface is measurably less accurate) you buy it from me. You can even nominate a neutral 3rd party to validate the data if you like.

I can eat the loss if I am wrong.