[selkin]

let's say I have a PC with an integrated soundcard which has spdif In and Out.
I buy a DAC which has spdif In and Out as well. I connect them together.

Will the digital signal bear the bad qualities of the integrated DAC chip of the motherboard or the signal will be "untouched" when it arrives to the ecternal DAC ?

And is optical interconnect the same as usb in the way of transmitting data between DAC and PC ?

 

[1UP]

1. It won't bear the qualities of the DAC as it's not gone through conversion to an analogue stage. Untouched is a different matter depending on whether you subscribe to the idea that different transports are susceptible to varying levels of jitter and indeed whether jitter matters or not.

2. No. Optical is electrical S/PDIF.

 

[pedxing]

Chances are, your soundcard will be smart and just send the bits out of the SPDIF output straight into the input of your external DAC. I wouldn't worry about it too much, just make sure you got the sound software/drivers on your computer set up correctly.

Although, your question is not entirely silly or stupid. Many of the ipod docks that claim digital audio actually resample the analog output from the ipod and then pump it through a fancy DAC. They do what you feared in your silly question. As far as I know, Wadia is the only company who builds a fully digital iPod dock.

USB is entirely different from SPDIF. Go and google for USB specs if you want to read how USB audio could be implemented and used.

 

[selkin]

hey, thanks for the answers

and do you think badly coded/developed drivers can result in bad SQ? even if it is just software ?

 

[1UP]

Well, DSP can be just software, and mess with your output. On the whole, though, things have come a long way from the SB Live bad times.

Poor latency and stuff is a function of bad drivers, though this more affects recording than playback.

 

[apatN]

Digital vs. digital vs. digital.

 

[insyte]

I also want to try connecting my pc to my dac via coax instead of usb. Will need to buy and install the connector to my motherboard first

 

[krmathis]

1. It wont bear the bad qualities of the integrated DAC chip of the motherboard, as it will be sent digitally to the external DAC.
2. No. Optical use light, while USB use electric current. Totally different standards.

Don't loop-back using both inputs and outputs though. Only output on the sound card and input on the DAC

 

[selkin]

didn't mention to loop it back.

I actually thinking of getting a tc electronic 24D which has(high res. picture) optical in and out. I plan to use that to get rid of the noise coming from my computer, but with optical I'm not going to be able to use the card's 4 output I presume. because altough both usb (in this case firewire) and optical are digital, the optical is just not capable of doing the same tasks that an usb or firewire would do.
well I don't know how to say this better

anyhow, I'm just not gonna be able to use the card's features through it's optical I/O. that's it?

you see. this is not clear. why is optical not capable of doing such things.

 

[krmathis]

Quote:

Originally Posted by selkin /img/forum/go_quote.gif didn't mention to loop it back.

Ok, not directly.
But that you mentioned soundcard with spdif In and Out, DAC with spdif In and Out, and connecting them together. So no surprise that I though you were hooking it all together...

 

[selkin]

now I don't know why did I write that. I was in fact thinking of looping back.
it was a bit too late for posting messages on forums. just like now.

hope you disregard my sillyness

anyway, do you think it's not a good idea to loop back digital signal ? and why ? because it'll act like an analog loop back ?

 

[1UP]

It's pointless.

 

[krmathis]

selkin. No harm done! I just disregard that part...

Looping back simply make no sense, as you want a clean digital signal straight into the DAC. No fuss needed.

 

[selkin]

cheers

yeah... I was hoping an optical IN & OUT together would equal an USB. however somehow I knew it would not be just that easy

well... gonna have to buy a new PC to get rid of the RFI noise than..
can't really go around it.