Roland Micro-Cube problem

I finally upgraded my amp from the Denon stereo to a Roland Micro-Cube last night. Sounds really great, but I get a nasty hum on the Micro-Cube.

The hum disappears when I touch the volume antenna on the Theremin.

When I touch the Micro-Cube, or the jack on the cable, I create low notes from the Theremin. Something is clearly very wrong. Never any problems with the Denon.

The Theremin is the Etherwave standard. My music room contains only one curcuit.

Any suggestions to what could be the problem? Will it help to run the Micro-Cube on batteries?

/Andy

The answer to my second question is: no, it does not help using batteries in the Micro-Cube. It does not help either to turn the theremin power adapter in the outlet. It does help a bit to place the Micro-Cube in front of the Theremin. Can the cable be the source of the problem?

I know many other uses the Micro-Cube, so any suggestions are still welcome.

/Andy

I once had very similar symptoms, although with a different amp and theremin, and it turned out to be a grounding issue. Is the outlet in which you plug the theremin and amp properly grounded? Have you tried using a different one? Does the theremin sound ok if you run an audio cable from your waist to a metal part of the theremin? (note that I don't know if doing this last diagnostic is safe for health, I just know I survived...)

I will try the audio cable thing tonight, but as I recall there are really no metal parts on the theremin apart from the antennas.

I have tried several outlets without success, but the whole room is just supplied by one curcuit, so I don't think it matters which outlet I use.

I have another room apart from the house, built in 2005, with electrical installations up to code. I will try to set up out there tonight, and see if that helps. The electrical installations in the main house is from the the last renovation in the 1950'ies.

Must remember to thank the Denon stereo for handling this problem for me for almost a year.

/Andy

Have you tried the Cube amp with an instrument other than the theremin or with a different instrument cord?

With the theremin, it is common for the pitch to rise substantially whenever you touch any metal part on the theremin, the cord (plugs), or on the amp.