[sdiy] preferred shielded cable, connectors

[Paul Higgins]

I'm pretty sure that you can't do this telescoping ground thing with 
anything except balanced audio.  I remember trying it to eliminate 
ground loops with some unbalanced equipment, and all I got was even 
worse hum.  I know for sure that the equipment had a proper ground 
through the power supply, because I built it.  The problem was 
interfacing it with some old commercially-made pro audio stuff.

The solution wasn't much fun...replacing the rack rails with wood, and 
modding every piece of equipment with a ground post; then a separate 
heavy-gauge ground wire was run from each device to a ground buss I 
found at the hardware store.  Ugh.

-PRH

On Thursday, April 22, 2004, at 04:46 PM, Scott Stites wrote:

> Seems to me, and I could be wrong, but the rule of grounding only one 
> end of
> a shielded cable usually applies to shielded cables that you're 
> running from
> the PCB of a module to the panel connectors, ostensibly to prevent 
> ground
> loops while still providing a grounded shield for the signals that the 
> cable
> is carrying.
>
> Cheers,
> Scott
>
> ----- Original Message -----
> From: "Tim Parkhurst" <tparkhurst at siliconbandwidth.com>
> To: "'jeff brown'" <guitaricon at comcast.net>; "DIY SYNTH"
> <synth-diy at dropmix.xs4all.nl>
> Sent: Thursday, April 22, 2004 10:36 AM
> Subject: RE: [sdiy] preferred shielded cable, connectors
>
>> So what's the deal with the shield connection on 'store bought' patch
> cords?
>> Do they connect it at both ends? I've always heard that you should 
>> only
>> connect the shield at one end of the cord to prevent ground loops. 
>> Now,
>> perhaps this isn't as important when you're patching between modules 
>> in
> one
>> system...right? (since all the modules in a case are going to be 
>> sharing a
>> common ground through the power supply anyway) But this DOES become an
> issue
>> when patching from one piece of equipment to another (synth to mixer, 
>> for
>> example)...right?


Paul Higgins
email: higg0008 at tc.umn.edu