Hi. I'm running PT10 on an iMac w/ Snow Leopard, using an old Digi 002 as the i/o. The Digi connects to the iMac via 1394 Firewire. There's an awful digital "grizz" that comes through the Digi, both at the outputs and the headphone jack. It only happens when I launch a PT session, and what's more weird is that I can almost manipulate the noise with mouse motion/clicks. I did some reading, and some people recommended some software called CHUD that might help, but is this a software issue, or hardware? Thanks much!
I have seen this when you have the Macintosh audio connected to an external pair of speakers or a mixer. It ends up being a grounding issue. Better to buy an isolation transformer if you want audio out of the Mac to an audio device.
Start by disconnecting the mac audio if you have it connected.
ACSR Elite/Avid ACI, Apple Certified Technician
Consulting for Workflow and Digital Technologies at Comprehensive Technical Group