[sdiy] Reverb picking up power supply hum

[Jean-Pierre Desrochers]

The thing you can do is put the 'output' side of
your reverb thank as far as you can from the synth power
supply transformer. This is the supply transfo 60hz
that your reverb output transformer picks up.
Long ago this was a problem while some Hammond
organ had a reverb unit installed inside the organ.
Sometimes the tank was not oriented correctly
from the organ supply transfo causing induced hum.

JP

----- Original Message ----- 
From: "Scott" <Scott at scottwick.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Friday, April 24, 2009 3:39 PM
Subject: [sdiy] Reverb picking up power supply hum


> If I mount my power supply (power-one 3 amp) inside my synth cabinet, I 
> pick up some hum in my reverb (tellun neural agonizer).  I've tried 
> grounding the power supply frame to earth.. the reverb tanks to earth.. 
> various grounding schemes using the synths neutral line, etc.
>
> Is there anything I can do?  There isn't a lot of room but I might be able 
> to fit the p.s. inside a cage if that would help.
>
> I know building a little case for my power supply and leaving it external 
> would work, but that is definitely the last thing I will do.
>
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