Re: Weird consumer problem

Paul Stamler <pstamlerhell@xxxxxxxxx> wrote:

A friend of mine asked for help on this. He's recently installed a new, not
fancy turntable from Gemini in his home stereo system, one that's been
modified to play 78s and rebranded "Rek-O-Kut". He's been getting a bad buzz
from it, which wasn't there on his older JVC turntable. I checked to see
that the ground wire was properly connected; it was. I unplugged the table
from the Onkyo receiver's phono inputs: no buzz, just some very low-level
hiss.

Okay, says I, we've got some kind of ground loop. So I unplug everything
that's connected to the Onkyo except the turntable and speakers; it still
buzzes. The owner has everything plugged into a power strip; wondering if
the power strip could be faulty in some way, we replace it. No change.

Then I unplug everything from the power strip except the turntable and the
power amp. The buzz is gone. Aha! Ground loop with something else, messing
with the ground system of the Onkyo which is probably no great shakes on
grounding. So I start plugging things in again, and when we plug in his CD
recorder, the buzz comes back.

So the problem seems pretty clear -- ground loop via the four cables (L & R
send and receive) going from the Onkyo to the CD recorder. I unplug them.

The buzz doesn't go away.

The CD player is radiating trash onto the power line and the turntable
is picking it up? Could be the power line filter on the CD player causing
the problem. The power line filter may be in front of the switch and it
may be leaking a spike of trash to ground on each cycle.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
.

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