AW: AW: To earth, or not to earth...

[Magnus Danielson]

>>>>> "HJ" == Haible Juergen <Juergen.Haible at nbgm.siemens.de> writes:

 >> 5) Systems can be cascaded together with one (and only one)
 HJ> ground path
 >> between them.  (I think there could be a problem here....)

 HJ> There are problems.
 HJ> I have my CS-50 connected to the mixer with its unsymmetrical output.
 HJ> (10m cable length).
 HJ> When I also connect the JH-3 Modular's Sample and Hold output
 HJ> to the CS-50's external (modulation) input, I can choose between two
 HJ> evils:
 HJ> With the shield connected, I get a severe ground loop and HUM.
 HJ> Without the shield connected, the Sample and Hold bleeds ito the
 HJ> Mixer over the shared GND connection.
 HJ> No Idea how to cure this without going balanced ...

Hmm.. some loose thougths...

Sounds like you would benifit from a transformer isolation to cut the
groundloop without riscing or having to do the jump in the signal.

How tigth is the chassi/protection ground connected to the signal
ground in the CS50?
If it too tight, maybe modify it to be several ten's of kohms, then
will the ground loop have that resistor in it and it will act as a
current limitor...

One could also have similar things for the shield, but I think it is
unwise...

Cheers,
Magnus