[HAM] Vibrato Problem

[David Anderson]

Mark,

I had a similar problem once, so I'll tell you what I found.

I was getting a low pulse that got louder in C positions of the  
vibrato switch and louder in C3 than C1 or C2.

This was a chopped organ that I put a Trek SSP-3 preamp in, and the  
case was chopped such that there was little room in it for anything  
but essential components.

The back was hinged, so I installed the preamp on the back (outboard  
expression pedal), but I found that I got a pulsing hum when I closed  
the back.

It turned out that I had positioned the preamp's power supply  
transformers so that they were too close to the vibrato line. I had  
to re-position the preamp to move them further away.

Got a reverb unit or anything like that in the organ? Can you *move*  
it and see if the annoying noise is from some unexpected source?

David