Extra Noise via midi power

[JamsLoud]

Hello,

I have noticed that when I power devices with the USB ports on the face of the MRCC it add's a lot of extra noise to my audio signal coming from the synths. 

Some of my synths can take power and midi with the USB port which is great for my configuration, but when doing this via the MRCC...NOISE.

Anyone else having this same issue?

Attached is a picture of the audio from a synth powered via normal power, then the MRCC adding lot's of noise to the signal.

THANKS,

JAMS

[Jesse Johannesen]

Huh, I haven't experienced this before so there is likely to be some aspect of this that we can change to get that back into the expected range. Let's start by changing where the unit is plugged into the wall power. Try to pick a spot without a power strip, and if it's already a direct connection, lets try a different plug (on a separate breaker maybe). Next if we haven't solved it with those steps, let's see if it's still there if we take each USB host powered device out of the equation one by one. Next we can try powering the MRCC unit with a different USB C power source, (minimum 500mA supply, and in that case let's only power one synth).
That should give us some useful info hopefully. Let me know if any of those steps sorts it out. Also let me know what the synths you are using are and maybe I can do a little parallel research on my end.
Jesse

[Darryl]

Also try plugging MRCC power supply into the same outlet as the PC that MRCC is connected to.

I don't have a noise issue with MRCC, but in my studio I can get ground loops that make a nasty hum. There are USB isolators that can remove ground loop issues from USB. I use one like this on my USB DAC: https://ifi-audio.com/products/idefender-plus/

If re-arranging the way power is connected doesn't help, something like that on the MRCC USB PC connection may help. You might find a cheaper one if you decide to go this route, but the chips to make these are expensive. MRCC PC port is USB 2.0, so don't need anything fancy.