--- In "Russ Wigh" <> wrote:
>
> I have also found that when I use this connected cable business and
A/C
> power to the recorder, I get a loud buzz that makes recording
impossible.
> With AA battery power the buzzing noise does not occur.
>
Some recorders (Sony HiMD spring to mind :) AC power supply has a very
significant leakage current, presumably due to capacitive coupling from
the low voltage side to the AC mains. When the recorder is placed near
a grounded surface or even a large lump of ungrounded metal, the
leakage current flows through the recorder into the input stages via
the microphone lead capacity to the metal. And you get hum and buzz,
which gets worse as you place the recorder/mic cable closer to the
grounded surface/ large lump of metal. I can't use my NH700 HiMD to
record on the mic input using the Sony AC power supply for that reason.
Your long cables may be acting as the capacitor with the ground. You
could try earthing the shield connection at the recorder, but it does
sound like you should eliminate the motley collection of balanced to
unbalanced connections you are using first, particularly as it is
losing you signal level. That is not right at all - one bal/unbalanced
conversion should'd do that. Go balanced as far as you can, and if you
must convert to unbalanced do that close to the mike end as you can.
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