> On 7/6/2012 2:42 PM, Jerry Kaidor wrote:
>> It reminds me of the importance of ground loops.
>> Ground loops and me - we have a history.
>
> There is no such thing as a "ground loop" -- it is a totally false
> concept.
The actual cause of the hum/buzz problems we blame on these
> imaginary "ground loops" are LEAKAGE CURRENT from the AC power system,
> the IR drop in the green wires
*** Um, the OM-1 had no green wire. Two-wire cord.
You seem to have some problem with the words or sounds "ground loop" - OK,
let's call it a Squigblap. My OM-1 suffered a squigblap - voltage at
unexpected places caused by IR drop in chassis connections which developed
unexpected resistance.
I find that squigblaps are generally or often caused by running
multiple incompatible signals through the same conductor. I eliminated
60Hz squigblaps in my old ARC5-cabinet linear by using separate returns
for pretty much everything, especially the filament AC. Having
separate return
conductors for each signal pretty much naturally leads to a "single point
ground".
Doing electrical work on my airplane, I installed a fancy GPS/Radio
unit. Garmin fought with squigblaps by having a separate return for
every single signal. Lots and lots of returns. A shop fabricated me a
wire harness for it - they had consolidated some of the power returns. I
took the harness apart and added all the mising returns. It was a nice
quiet installation.
- Jerry Kaidor,KF6VB
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