gazraman

It would be interesting to know if you experienced the same interference sound on your functioning imac with a 3.5mm stereo to rca lead direct into your amp from the headphone jack. The fact that the noise affects the USB port suggests something like an earth fault or other electrical gremlin.

I just got a brand new 3.06 21.5 inch imac and plugged my fostex pm2 powered studio monitors into the headphone jack of the mac. The sound was unacceptable with a huge amount of interference noise from the HD, screen and mouse. It sounded like a 50's robot. I then tried using my old behringer uca 202 interface that came with an old mixer. The same noise was apparent on the USb connection, which I find extremely weird. I eventually toslinked it up to an old sony minidisc recorder which i cue up to act as a DAC and it is completely silent although not a lasting solution. It seems on mine the only solution is optical which i can see causing some real problems later on. Anyone think this is a fault with this unit or is the whole design flawed?