Don’t know whether this is normal but when I have my cv expander attached to minimoog voyager I get a very high frequency almost inaudible as background noise when any note is pressed especially at higher output volumes. Without it attached there is no background noise there at all. I wondered if the cable is picking up interference? Anyone else notice this? Is there a solution other than adding a gate when recording to remove the frequency?
Thanks
I just got one today and it is not humming as you described… just wondering did you install that little bridge adaptor between the connectors at the end of the ribbon cable, as described in the notes that come with the unit?
Yeah i did fit that,
Thanks for the reply. Knowing that it isn’t supposed to be there helps. It must be picking up interference.
It turned out to be the cp251 which is powered via the vx-351 in the moogerfooger rack. With the feet screwed into the rack there is interference. Bizarre, I took out the screws and the high pitch noise has gone.
You didn’t mention the CP-251 in your OP.
Yeah, hum from powering the CP-251 off the VX is a known problem. The fix is disconnect the inner connection and use a wall-wart to power the CP-251.
Thanks for the help with this 
Me too!
Sorry for the bump, but I just got the 351/251 combo installed. I don’t get a hummmmm, I get a quiet but annoying high pitched Squeeeeeel. The high pitched noise is the 251? I’m not sure how I would get the wall wart plugged into it from the rackmount.