AW: "gndloops"

[Martin Czech]

> The omnipresent magnetic field (50/60Hz) is the bad guy, IMO.
> The point is that a magnetic field does induce a *voltage*, not
> a current, in a closed loop.
> 
> The Maxwell equation to look at is   rot E = - dB / dt.
> 

[Good point, point given , set Haible :->). Of course I know Maxwell's
four equations. But writing my mail I was more thinking about
currents and how they turn into error by Ohm's law.  I think it is just
another perspective]

Now, I decided that magnetic ac fields are not regarded, because I have
to keep them low anyway, e.g. for other guitar gear.  That's my
situation at home.  If synths have to live in a highly hostile magnetic
field environment, however, then  groundloops via patchcords are
terrible, no question. So this initial assumption may be wrong.

The question was for me to find a tradeof and to avoid a totaly
balanced system (maybe this was not clear in my first mail). I know that
it is not perfect. But a conventional wired system is worse than that.

Further: If I set up a system in the proposed way, and I have the
feeling that problems get worse, I can always change it afterwards:
simply connect the different grounds on the module pcb via bridges
instead resistors (in fact, there are "0" Ohm resistors for that purpose
on the market) and disconnect/high-Ohm-connect the cable shields at one
side. This is possible. But if you start with a "normal" system, it is
almost impossible to do it the other way after you have finished it.

m.c.

------------------------------------------------------------------------
m.c. has made it finally:  3 CDs out now; 72 min. minimum; "1"
(1994-1995),"2" (95-96),"three" (96-97); experimental stuff; mostly
Eimert/Stockhausen style; but also modern popular style