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I' m wondering if someone has any experience with this issue:
my mtp av USB is causing an audible hum in my soundcraft compact 10
mixer. I have a rack unit about 3 ft tall with my mixer on top of the unit and the mtp
on the top rack. When I power the mtp on I can hear a hum in my
mixer through the cons and monitors. When I put the mtp at the bottom of the rack, the hum is not
heard.
I hear an audible hum in monitors and in cans when my compact 10 mixer and mtp av USB
are close together in my rack.

I had tried to trouble shoot this issue by putting different rack units
under or on top of the mtp to see if the humm can be duplicated.
I do not hear humm with my 8 pre or my 828mk3.
The humm only occurs when my mixer and the mtp are close together.
When I put the mtp at the bottom of the rack far away from the
mixer the hum disappears.

I spoke with motu tech who said I should turn off unit and switch
red voltage switch to 220 and back to 110. I did this and the results
were the same. Motu also said it might be a blown fuse. I tested the
Fuse and it seems to be working correctly. Any ideas what's causing this?
Thanks

I have nothing plugged into my mixer or the mtp and I still hear a humm
when they are close together. Any ideas what might be causing this?

Thanks for your help

Sounds like the MTP power supply is radiating energy your mixer is picking up. Since the MTP has a voltage selector switch, it probably uses a transformer as opposed to a switching power supply. Solution: you know it already. Put the MTP at the bottom of your rack and leave it there.

Thanks for your response. Do you think this
hum would be present in my recordings even
if I swap it the mtp to the bottom of the rack?
How come my other gear doesn't pick up the humm?
Have you ever experienced this with any of your
gear? Is their an issue with power supply?
Sorry, I'm not very good with electronics.

Thanks again

J

Some equipment is more susceptible to hum pickup than others. Do test recordings of silence for all of your audio devices/paths and play each back at a high volume; you'll know if you have a problem.

Thanks Again for the advice. I will try what to said.