Try plugging the MOTM AC cord into a 2-wire adapter. I bet it's your house
wiring.
Paul S.
----- Original Message -----
From: "J. Larry Hendry" <jlarryh@...>
To: <motm@yahoogroups.com>
Sent: Sunday, February 11, 2001 6:14 PM
Subject: Re: [motm] Ground Loops
>
> ----- Original Message -----
> From: GeorgeK <george.kisslak@...>
> To: <motm@yahoogroups.com>
> Sent: Sunday, February 11, 2001 4:43 PM
> Subject: [motm] Ground Loops
>
>
> Well, I just finished building my first modules, the 900, 120, 420
> and 320, and amazingly everything seems to work (and looks great
> too!) What a sweet filter the 420 is! (In just a few more days, my
> girl gets some flowers, and I get some sound sources - my 2nd order's
> in!)
>
> I've run into a little problem, however. When the 900 power supply
> is installed into a rack with the modules and is powered on, I begin
> to pick up some minor 60hz hum; not much, but enough to ruin the dark
> background - Bummer. (FYI, the rack is wood frame with metal rails.
> A mixer is in a separate all-metal rack. Everything is plugged into
> the same power strip. Patch cords are shielded) I pick up hum
> regardless of which jack/module I plug into. I visually checked all
> coax solder joints and ground wires; everything looks ok. Funny
> thing is that even when I disconnect all of the modules' power cables
> from the 900, I still pick up hum whenever the 900 is on. There's no
> hum when the 900 is not in the rack, whether connected to and
> powering the modules or not.
>
> Is appears the AC ground is part of the common ground with the
> modules when installed in a rack with metal rails. This is by
> design, correct? Is it possible that the mixer being in a separate
> rack is a problem? If anyone on the list has some insight, that
> would be great.
>
> Cheers,
> George
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