late one : To earth, or not to earth...

Don Tillman don at till.com
Sat Jan 10 18:41:11 CET 1998


   From: Martin Czech <martin.czech at intermetall.de>
   Date: Fri, 9 Jan 1998 13:37:12 +0100 (MET)

   I never had problems with consumer hifi stuff, because there are no
   ground loops, all chassis are separated from earth, the internal trafos
   are insulating types, safe. All devices have their own power supply...

It's really not difficult to make ground loops happen in consumer hifi
stuff.  I mean, that little seperate turntable ground terminal on the
back is there for a reason.

(I know, nobody makes receivers with turntable inputs any more.)

Okay, when you connect a VCR and televsion set to the hifi you have an
opportunity for a ground loop depending on the situation.

   Now, would it be a stupid idea to do this in a modular synth:  Every
   module gets not only it's own regulator and overvoltage protection
   (this is good practice) but also it's own trafo , rectifier etc., i.e.
   now the modules have no ground connection to each other. 

I'd say it's not a good approach.

First off, ground loops only happen when you have one or more higher-
powered noisey devices sharing the same ground wires as one or more
low-level signals.  That's generally not the case in modular synths.

And as soon as you connect two external devices with their own grounds
to a group of modules connected together (and that's typically going
to be the case, eh?) you've got the potential for a ground loop.

(Also power supplies are the least fun part of a synth building!)

  -- Don



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