Mcintosh MA-5300 USB problems

Bear with me. I was born with a strong back and a weak mind.

In the past I had many problems with USB connection between my Mcintosh MA-5300 and a computer. Both a Mac Air and a Mac Mini. With and with out Roon.

A few months ago I installed a dedicated circuit to my audio equipment. Never realizing that fixed my problem. I said I was slow.

So I decided recently to plug in a watt meter to see what kind of power I was pulling for the MA-5300. Moved the plug to an outlet that I had previously used for the equipment with the watt meter. This outlet was visually easier to read the LCD display on the meter. Restarted the Mcintosh, rebooted the MM. USB kept dropping out in Roon, both the MM Core and the Mac Air control.

Ok so I removed the meter between the outlet and the MA-5300. Maybe something is wrong with this meter, it was only $20. Restarted everything. Same results. USB is constantly dropping in and out every 1/4 second.

Plugged the MA-5300 back into the dedicated circuit and Roon core and control are happy. USB is solid and no drop outs.

I know that there a some complaints about the Mcintosh USB drivers, but I never realized how sensitive this would be to power.