Is it true?

rick57 · 30th October 2006, 12:41 PM

That in PC audio, jitter is not really an issue?

Thanks

philpoole · 30th October 2006, 11:22 PM

Hi Rick,

If you're using an external DAC with your PC, be it on a USB cable or a soundcard, its a DAC. In this case, jitter will of course be an issue.
Within what context are you referring to (i.e. am I missing something?).

Cheers,
Phil

rick57 · 31st October 2006, 02:42 AM

Hi Phil,

I read www.positive-feedback.com/Issue22/nugent.htm

where an EE suggested/ claimed in PC audio, jitter is not really an issue, though without any detail etc

I'm a sceptic . . but

I’m going over to PC audio for a audiophile system, and a family system; one internal soundcard, the latter external to a 2nd hand notebook. (Both M-Audio, cheap off eBay)
While planning these two PC audio systems, I was hoping for some similar conclusions/ clarification/ measurements

Cheers,
Rick

metalman · 31st October 2006, 06:37 AM

Somewhere on the TI website there is an article on the development of the SpAct architecture that they had to develop to create the compatability between USB (an asynchronous signal) and digital audio formats (which are synchronbous). It details in more detail than I could ask for the issues surrounding jitter and USB audio transfer. I'd recommend looking it up.

The short answer to your question from that article is that the USB transfer eliminates all jitter related to the normal sources in a CD player, but does not eliminate jitter completely. There is still jitter from the innacuracies of the clock source feeding the USB converter chip, the accuracy of the PLL within the USB chip, and possibly even from noise in the power supply feeding the USB chip.

Cheers, Terry

rick57 · 31st October 2006, 09:50 AM

Thanks, Terry

I'll check it out

30th October 2006, 12:41 PM	#1
rick57 diyAudio Member Join Date: Dec 2002 Location: dry ol Melbourne Australia	Is it true? That in PC audio, jitter is not really an issue? Thanks

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30th October 2006, 11:22 PM	#2
philpoole diyAudio Member Join Date: Oct 2004	Hi Rick, If you're using an external DAC with your PC, be it on a USB cable or a soundcard, its a DAC. In this case, jitter will of course be an issue. Within what context are you referring to (i.e. am I missing something?). Cheers, Phil

31st October 2006, 02:42 AM	#3
rick57 diyAudio Member Join Date: Dec 2002 Location: dry ol Melbourne Australia	Hi Phil, I read www.positive-feedback.com/Issue22/nugent.htm where an EE suggested/ claimed in PC audio, jitter is not really an issue, though without any detail etc I'm a sceptic . . but I’m going over to PC audio for a audiophile system, and a family system; one internal soundcard, the latter external to a 2nd hand notebook. (Both M-Audio, cheap off eBay) While planning these two PC audio systems, I was hoping for some similar conclusions/ clarification/ measurements Cheers, Rick

31st October 2006, 06:37 AM	#4
metalman diyAudio Member Join Date: Jun 2003 Location: Calgary, Alberta	Somewhere on the TI website there is an article on the development of the SpAct architecture that they had to develop to create the compatability between USB (an asynchronous signal) and digital audio formats (which are synchronbous). It details in more detail than I could ask for the issues surrounding jitter and USB audio transfer. I'd recommend looking it up. The short answer to your question from that article is that the USB transfer eliminates all jitter related to the normal sources in a CD player, but does not eliminate jitter completely. There is still jitter from the innacuracies of the clock source feeding the USB converter chip, the accuracy of the PLL within the USB chip, and possibly even from noise in the power supply feeding the USB chip. Cheers, Terry

31st October 2006, 09:50 AM	#5
rick57 diyAudio Member Join Date: Dec 2002 Location: dry ol Melbourne Australia	Thanks, Terry I'll check it out

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