Mbox Analog Input with Digital Output

[Alhuero]

So I thought I figured out a novel way to use the pre's on the Mbox to feed into an external 8-track recorder with suspect pre's, but I'm getting some strange clicking (jittering) on the inputs after running them for awhile.

What I've done is hooked up two microphones to the analog inputs on the mbox and setup a phantom session enabling record on two tracks panned hard left and hard right. I've then taken the S/PDIF RCA digital out of the mbox to a converter which translates the RCA to an Toslink optical output; the required feed to my recorder.

It all seems to work fine for awhile, but eventually I start getting a clicking noise on the mbox inputs that continues even with the mics disconnected. The only way to get rid of it is to close the session and reopen it.

I'd be interested in any guesses on what might be causing this.

Thanks, Alex