[sdiy] Grounding of inputs/outputs for modules

Elby Designs elby_designs at ozemail.com.au
Fri Aug 3 13:27:11 CEST 2012


My understanding...

If all connections are within the same system then having the sleeve
grounded or open would make no difference as the signals are all referenced
internally to the same common.
If you are using single core patch leads then again it would make no
difference.
Having one end of a screened lead open (i.e. the screen is connected to the
body of the jack at one end but not at the other) then having the socket
sleeve grounded would allow the screening on the lead to do its job and
`screen' the signal core from any stray/radiated noise. For example if you
are patching the WHITE output from a NOISE module you don't want that signal
being radiated in to other passing signal leads.
If you are using fully screened leads then again it shouldn't matter if the
sockets are grounded or not but the screening will only work with the
grounded sockets.
As far as I know, none of these situations will cause ground loops or
associated noise problems.

Where the problems start are when you connect to a separate system which has
a different signal reference and its own grounding.

I believe here that the rule should be that you make one common connection
between the systems to establish a common reference and address ground loop
problems at that point. After that you should be able to patch with grounded
or ungrounded sockets and screened or unscreened leads without problems.

In theory you can provide your modules with a signal common, a power common
and a `panel' common and control all of these and, specifically, steer the
panel common to true earth. In reality this usually never happens unless the
whole system is built with compliant modules, power supplies and grounding
paths. For example, Oakley provides 2 grounds on his busboard allowing his
modules/system to take control of grounding problems but as soon as you plug
in most modules from most other manufacturers, that control falls flat on
it's face.


Best Regards
Laurie Biddulph
Mobile: 0400 257 645
Phone: +61 (0)2 4340 0938
Web: www.elby-designs.com

Elby Designs
9 Follan Close
Kariong
NSW 2250
Australia


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Tom Wiltshire
Sent: Friday, August 03, 2012 8:39 PM
To: synthdiy diy
Subject: [sdiy] Grounding of inputs/outputs for modules

Hi All,

A quick question if I may:

I'm building some Eurorack synth modules. Normally when wiring up jack
sockets, I'd have the sleeve grounded, and the signal on the tip. Is the
ground necessary for synth modules? Seems to me that with everything on the
same power supply (and therefore the same ground) I'm going to be creating
lots of little ground loops if I connect it.

What's the standard practice for this?

Thanks,
Tom

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