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
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