I have had the IDE header problem, but touching up the solder joints seems to have fixed that. In my case, I'm not streaming my music from the hard drive (which is actually a CF card) but rather from the Ethernet port, using my custom player software. The front outputs are fine, just the rear are acting up. I don't have a tuner.

I've looked at the PCB and can't see anything obviously wrong. I'm going to touch up all the related solder joints and I think I'll replace those BB INA2137UA op-amps for good measure. If the op-amp was ESD zapped I'd think it could have this problem, too.

I tried wiggling the unit in the dock while the noise was happening, and no change. I also cleaned the dock connector with a little DeoxIT.

For now I've put in my spare empeg (always good to have a spare!) and it's been working fine.

Thanks for the help guys, I'll let you know how the resolder / op-amp change goes.