Hello-
I've got a Pismo which puts an awful 60hz hum when I plug it into the AC power
supply.(it is most noticeable if I am using iTunes and hooking it up to an
amplifier at a party.)It's almost as loud as the music itself.I am staying in
Mexico, and there is basically no such thing as a grounded outlet here,so what
I do is unplug it. and run on battery for 45 minutes (no more hum)
I checked out some other forums; perhaps I have a 'ground-loop' problem; I
haven't run my own ground wire outside yet (i think it needs to be driven 3
feet into the ground? Orhooked to a water pipe, etc)but I have tried plugging
in the sound system and the laptop into TWO separate circuits (I used the house
next door). Still, a ridiculous hum.
I'v got 2 white iBooks which do not have this problem.
So I'm guessing that once again my sound card is bad, on the Pismo?I've been
through two so far. Sometimes vocals on a song sound distant.
I've got a new (generic) charger, but the original Apple hummed louder.
One person suggested running a car power supply unit (110v to 12v DC), then
plugging in an inverter into that, which brings the power back up 110v, and
plugging the laptop into that.He uses that when onstage and he needs the laptop
to work without a hum. He says it's insane but works perfectly. Is there a
filter made to refine the AC or DC power,or a way to create a 'clean' power
supply?
Another suggestion was to REMOVE the grounding pin... I though the lack of
ground was my problem, originally.
Perhaps the PISMO is my problem, instead?
thanks,steve
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