USB SQ, what can one expect

Cerrot - you are correct...

Simply put...
- USB does send data in packets
- each packet contains a CRC - Cyclic Redundancy Check
- the CRC tells the DAC whether the packet received was identical to the packet sent
- Asynch USB allows the DAC to request packet re-transmission
- if incomplete the DAC requests the same packet until the CRC indicates the packet is complete
- even if the CRC is corrupted the DAC simply requests the packet again
- the DAC then assembles the data stream once complete and plays it.

If this did not work the DAC would simply stop playing or skip - which in my case it does not.

This is the same technology used to transfer the spreadsheets and accounting info of Fortune 500 companies - and it works - otherwise computer systems in general would fail miserably - they don't

S/PDIF does not have CRC checks and balances and therefore you NEVER know if bits are getting dropped.

Yes - there may be other issues with USB, but transferring the correct data stream to an Asynch DAC is not one of them

Here's another link
http://www.thewelltemperedcomputer.com/KB/USB.html

Is it the perfect solution - maybe not

But it is NOT as bad as you are portraying it

I think it really depends on which USB approach a specific DAC manufacturer has implemented.

I have observed power issues with DAC's that power the USB circuitry via the USB cable, which most quality USB DAC's tend to avoid

Regards

Willie - a dual cable may help, but it does not eliminate the common-mode noise problem.

Steve N.
Empirical Audio

XMOS provides a tool to record errors on the USB cable. Errors do happen occasionally.

Gordon Rankin believes that they occur often and are the cause of some SQ issues. I'm not so sure...

Steve N.
Empirical Audio

Willie, you definitely know more about USB than I do. I can't stand the sound and can't stand how they shoved it down everybodys throat. The USB is a filthy, disgusting place. Iwill check the link.

Cerrot: "I can't stand the sound and can't stand how they shoved it down everybodys throat. The USB is a filthy, disgusting place. Iwill check the link."

Interesting choice of phrasing. What did USB ever do to you that you should harbor such anger toward it? It just seems like a disproportionate response for the subject at hand.