Question about S/PDIF coax>TOSlink conversion

Hey Hardware Forum!

I'm contemplating buying the RME Babyface, as it seems to be a better choice for my my current needs. I have an Audient MiCo standalone micpreamp/AD converter which I'm connecting to my current interface (Focusrite Saffire Pro 10) via coaxial S/PDIF. The Focusrite seems to have some problems staying sync'd to the Audient and frequently drops out completely mid-session requiring restart of both the interface and SONAR.

I'd like to keep using the Audient with the Babyface, but since the Babyface doesn't have a S/PDIF coax input, I'll have to use a coax>optical converter.

Question is, is it just as easy as that, or may there be problems with sync or otherwise?

Sven

"it depends"... in theory there should be no problems - I've used the M-Audio converter and patchbay for years and have not had problems. However, every device is different, and I guess it is possible that someone goofed up their S/P-DIF implementation.

SvenArne


Thanks for your input!

Ohhey, your reply raises two questions:
- Is a wordclock feed "superior" to sending the clock along with the signal?
- Is the electrical/optical conversion process not necessarily 100% perfect? Can the quality of the clock and/or audio signal be degraded? Is this type of conversion known to introduce jitter?

Lastly, will using the Babyface as a 4-input device like this (2 x RME analog + 2 x Audient digital) cause the RME converters to underperform as a result of being externally clocked?

Sven

It's not so much that wordclock is a better way to send the clock, even if that's true in most cases, in your case it's being able to get clock back to the external device from the interface that would help. That way the interface can run off it's internal clock and send it out to the preamp to keep things in sync. If you only have SPDIF hooked up the preamp has to be your clock source since digital audio interfaces are single direction only.  That puts your clock down a wire to your main interface putting it and all conversion at risk.  If the interface can be the clock then only the converters in the preamp are at risk of getting bad clock.  It also means your software and interface can't autoswitch sample rates, a real bummer if you use different sample rates from time to time. 

Yes all digital audio connections have errors, they are not 100% perfect, and yes the clock can degrade going down a wire and if that is the clock source that means all the audio on every connection is now impacted.  The entire system has to run off that one clock signal.

Thanks for your wisdom, Ohhey! If my plan to use the two units together as I described is not optimal, I may be better of with the FireFace UC and take advantage of it's extra analog inputs. I know getting the BabyFace implies being stuck with the clock from the MiCo, and I really don't want to ruin the performance of the RME (even though I'm 99% sure I'd never hear the difference...)

Sven