[sdiy] Shielding

Don Tillman don at till.com
Sat Dec 1 21:28:59 CET 2001

Ingo Debus wrote:

> Like Theo obviously suspects too, this is most likely a ground loop
> problem. A friend of mine had that prob too with a Mackie mixer. It's
> difficult to disconnect signal ground from protective earth in these
> mixers without affecting electrical safety. All jacks are connected
> directly to the case as well as the power transformer, power switch and
> so on. An option is re-building the mixer's power supply into an
> external case (larger DIY project).


Almost all Mackie mixers have balanced line level inputs; it's an advertised
feature specifically for ground loop issues.  Just use a cable where the noisy
ground of the device connects to the negative "ring" input (keeping it separate
from the ground on the Mackie).

  -- Don

Don Tillman
Palo Alto, California, USA
don at till.com

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