>> The only problem I have had with this is AC (60 Hz) hum. It seems
> to
>> depend which outlet I plug into. Or perhaps it is the routing of
> the
>> extension cord. Anyway, I always need to check the setup for hum
>> before I leave it. Once I eliminate the hum, it works just fine.
>>
>
> Thanks for that Ed - perhaps you (& others) could say more about
> this mains hum issue. I've heard about this before but usually in
> relation to cheaper machines.
I have no experience of hum with my 744, but one thing I know is that
many wall-wart power supplies radiate a powerful AC magnetic hum
field. Putting such a power supply near a mic or the input
transformers of a recorder will always couple hum into the audio. The
Sound Devices recorders don't have mic transformers, and the power
supply may be transformerless, too, but that doesn't necessarily mean
that the input circuitry won't pick up a neaby hum field at high gain.
Try plugging the power supply into an extension cord and waving it
around whilst listening to the recorder's inputs. Keeping the supply a
couple of feet away from the audio components should be sufficient to
avoid this phenomenon.
-Dan Dugan
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