I have been a lot of tracking this week and thought orginally the noise was from the ribbon mic or GML mic pre I rented. Then I paid 5 hours of studio time to use a nice tracking room but with my gear so I could work out a deal. I'm bummed I didn't get much done because I spent most of the time troubleshooting this higher pitched buzzing/synth type sound. We (with the help of the engineer) realized we could remove everything out of the equation except the Fireface UC and it would be there if a mic was plugged. I tried different mic pres, different cables, different microphones, plugged into the computer/standalone mode, I tried all the different usb ports, I tried to use the battery on the macbook pro instead of being plugged in, I tried plugging the powerstrip into the ISO filter power thing the studio had that is supposed to remove noise from electrical outlet. So it seems like a grounding issue with my fireface UC and it's much more apparent at higher gain settings with mics like ribbons and dynamics. In standalone mode if there is no mic plugged in it is only hissy when you turn up the gain high but if you have a mic plugged in I get an electrical type hum that sounds much higher than 50-60hz(must be a harmonic of that tone?) Anybody else have this problem with a fireface and a macbook pro using dynamics/ribbons mics? When I got back home I noticed it is there but because I was using condenser mics before the noise was just turned down because I didn't have the gain turned up as high. I search the forums and saw that a few people have had this problem but I didn't read of any good solutions yet?

I would be extremely greatly if anybody has any advice on how to solve this issue!!