Digital connections and pure digital devices aren't going to pick up interference like that. It's likely only going to happen on an analog connection or an analog device. The third is harder to test, and you'd need to find out where it gets picked up. Older audio gear (or dare I say more 'audiophile') can be more sensitive to electrical disturbances on the power network.Īn electrician might be able to help you if this is the problem. One way to isolate this is if you happen to have a UPS powerful enough to handle a MP7,1 (it's able to draw a lot of power): power the MP through that (potentially forcing it to run from the battery by not disconnecting the UPS from the mains, just as a test). The earlier suggestion to try a power supply from another room is a good one, but you'd have to make sure to get it from another circuit down as far away as possible from where the rest of your gear gets its power. Together with other gear in your room, you might be loading a circuit rather high.

if you live in a country where the supply is only 110Volt, that supply can load power lines significantly. The MP7,1 power supply can use a lot of power, esp.

The second one depends a lot on your situation, electrical wiring in your place and even where you're located at around the world as the rules change with regards to electric installations.

The first is easy to test: turn off the microphone(s) and 'play' another silent source (like a CD player not having a disk in it) - your audio gear picks up EM interference from the mac ?.

- your audio gear picks up disturbances on the mains power caused (or made worse) by the mac ?.

- your audio gear picks out audio from the mac ?.

Mac pro 2007 power supply issues