Is SPDIF better than Line Input, and how to do it?

[Alistair]

Topic says it all really.

I have a FireWire Audiophile, and am curious- I currently use RCA cables to hook up the outputs of my SC-8850 to the line inputs on my Audiophile.

The FW Audiophile also has SPDIF In/Out, though.
Would I get better quality inputs from my 8850 if I used a convertor cable which turned the RCA outputs from my 8850 into SPDIF In's on my FW Audiophile?

I suppose what I'm asking is:
1. Does SPDIF sound better than Line In/Out
2. Does converting it (Line Out->SPDIF In) still produce the same result as a SPDIF Out-> SPDIF In combination

Regards,
- Alistair

[jbltecnicspro]

SPDIF would surely be of better quality because it's pure digital.  However, since your Sound Canvas doesn't have digital outputs, I don't think that you can hook it up to SPDIF.  The Line out -> SPDIF would essentially have to be an ADC - something that your sound card already does.  Does your sound card have a lot of noise - is that why you're looking for this kind of setup?  Anyways, while I'm not 100% on this, I believe that a simple converter cable doesn't exist, and that it would require an expensive piece of equipment - something needs to convert the analog into digital, and a simple cable adapter isn't going to do it.

To answer your questions, SPDIF would theoretically sound better than Line In/Out because it's not analog, and converting it would probably do nothing unless you've determined that your sound card has a noise problem with its line input.  Then it might help to convert to SPDIF, but I don't think it's possible - and if it is possible, it probably isn't practical.  I did some searching, btw, and the only thing that I could find was an RCA Coaxial to SPDIF - but this won't help, since the signal is still digital.  Like I said, I don't think this can be done without some sort of ADC. 

[Tom]

I think the noise associated with the LINE IN on the sound card is probably what Alistair hopes to eliminate, and I was wondering the same thing.  If there is a RCA-to-SPDIF converter, it could then bypass the standard analog IN jack on the soundcard...and possibly eliminate some of the noise inherent to my Riviera's LINE IN plug.  The noise ISN'T being generated from my sound modules; it comes from the analog LINE IN on the sound card.

[jbltecnicspro]

I think the noise associated with the LINE IN on the sound card is probably what Alistair hopes to eliminate, and I was wondering the same thing.  If there is a RCA-to-SPDIF converter, it could then bypass the standard analog IN jack on the soundcard...and possibly eliminate some of the noise inherent to my Riviera's LINE IN plug.  The noise ISN'T being generated from my sound modules; it comes from the analog LINE IN on the sound card.

But I don't think such a converter exists - not for cheap, anyway.  His output is analog, while the SPDIF input is digital - he would need some sort of ADC, and that can be expensive.  While it's possible to connect a digital output to a digital input via RCA - it's impossible to do so when the devices aren't of the same signal type.  For example, you'd never want to hook a digital output into an analog input, because you'll get a loud noise that will damage your stereo equipment and speakers.  Hooking an analog to a digital input won't damage anything - it just won't produce sound.

For example, I have an old 5.1 analog receiver that has six RCA inputs for the surround sound channels.  In order to hook an SPDIF system into that, I would need to have the digital signal go through a decoder which passes the signals to their proper channels (front, rear, center, etc..).  The decoder is an ADC.  Keep in mind that standard RCA outputs, like the ones the Sound Canvas modules use, are analog.  SPDIF is digital (it stands for Sony/Phillips Digital Interface, I believe).  Converting an analog signal into a digital signal is not something as simple as a cable crossover.

Besides, Alistair's sound card (hell, anyone's sound card with line input) does just this.  It converts his 8850's analog signal into a digital signal.  But the problem is that his sound card is generating noise.  In that case, he may have to upgrade his sound card.    Or, at least figure out what's causing his noise problem.

[Alistair]

Heh. Yeah, I found out it's not possible (or not worth it), as because what JBL said is true- SPDIF's digital, 8850's output is analog.

I need to get a new module with a SPDIF out sometime.

I presume that wouldn't work. But maybe..

I think the noise associated with the LINE IN on the sound card is probably what Alistair hopes to eliminate, and I was wondering the same thing.  If there is a RCA-to-SPDIF converter, it could then bypass the standard analog IN jack on the soundcard...and possibly eliminate some of the noise inherent to my Riviera's LINE IN plug.  The noise ISN'T being generated from my sound modules; it comes from the analog LINE IN on the sound card.

I don't think that'd work. I don't get noise on line in, my sound card doesn't have a line in like a PCI sound card does.

My sound modules generate a lot of noise, but nowhere near the amount of background that's already inherent when I have the card booted with nothing else going.


EDIT: I'm confused now. I'm an optimist about this sort of thing, so I hope it'll work. But the folks at Hydrogen Audio (my most respected audio information source) seemed to think it was pointless, so..

- Alistair

[Ari]

Could the noise problem with your modules be associated with electrical interference, Alistair?

[Alistair]

Yeah, we're having this discussion in the noise issues thread. I'm confused, myself. This thread's probably defunct now, I don't believe such a convertor exists and all advice I've had seems to indicate it isn't a good idea.

- Alistair

[djlc]

I need to get a new module with a SPDIF out sometime.

The Roland XV-5050 got one.

[Alistair]

Yeah, but I don't have like 300 US bucks plus to spend on a module. Struggling to find 100 bucks for a mixer!

Besides, once I save up, I'd probably get an XV-5080.

- Alistair

[MusicallyInspired]

So...not to derail the thread too much, but what's the difference between SPDIF and Digital Out?

[Tom]

Aren't they the same thing, except for the type of cables/connectors (i.e. toslink) used? 

[Ari]

So...not to derail the thread too much, but what's the difference between SPDIF and Digital Out?

They're the same, essentially.
SPDIF stands for Sony/Philips Digital Interface. Digital out is probably a more general term, whereas SPDIF is a specific standard.