XXHighEnd

Ultimate Audio Playback => Your questions about the PC -> DAC route => Topic started by: vrao on January 17, 2015, 06:41:39 pm



Title: USB bandwidth
Post by: vrao on January 17, 2015, 06:41:39 pm
After a talk with a manufacturer, I found not all USB cables are the same, most bandwidth limited.
So question is what mb/s is required for 768/32? And can our present USB cables handle it?

VJ


Title: Re: USB bandwidth
Post by: Nick on January 17, 2015, 10:49:19 pm
VJ hi,

768 by 32 bit requires bit transfer at 24.58Mhz. USB 2 in its fastest mode (used by the NOS1) has a carrier frequency on the cable of 480 MHz so even with the overhead of the USB protocol the 24.58mhz data transfer rate will not be a problem.

Where the cable bandwidth is important is that the link transfers data in short bursts carried at the 480mhz link speed so the cable needs to be good enough to accurately transmit the 480mhz carrier waveform.

Evidence is that there are a number of variables that go into making the transfer over USB run well, these appear to be linked to the accuracy of timing and electrical transmission and how effectively the data in at the receiving end can be clocked in. IMHO Cables are perhaps not the prime consideration but do have a role to play in getting the USB link to run well for music data.

Regards,

Nick.


Title: Re: USB bandwidth
Post by: vrao on January 18, 2015, 08:17:36 am
Hi Nick,
Interesting points you bring up!
This whole issue arose with the present USB cable, wherein I noticed data sync issues, and dynamic compression. I asked the maufacturer, and he mentioned it was good for only 196/24.

So to all who are looking into USB Cables, consider bandwidth as an important parameter.

The YFS cable is fine, and its tour will continue for now.

VJ


Title: Re: USB bandwidth
Post by: PeterSt on January 18, 2015, 10:17:31 am
49.152MHz (Mb/s). But then I am used to play stereo ...
:yes:


Title: Re: USB bandwidth
Post by: Nick on January 18, 2015, 11:20:43 pm
49.152MHz (Mb/s). But then I am used to play stereo ...
:yes:

Lol, yes I forgot we have two ears and two channels.

Best regards,

Nick.


Title: Re: USB bandwidth
Post by: vrao on January 21, 2015, 05:36:47 am
So, this issue arouse because recently all the music was trasferred from a 4TB SSHD to a 6TB spinning disc (5400RMP). A lot of classical music was added to the drive, and was the primary genre for the ears in the last week or so!
Maybe it has to do with the HD data access? As Nick said, the new drive stresses the bandwidth in some fashion?

I'll have to take my words back, spinning is a tad bit better.

Regards,
VJ