[Don Pearce]

nospam wrote:
Hello,

We recently had a heat wave on the East coast starting on Saturday. That
same day I turned on my home recording computer system and had a nasty hum.

I ripped apart the system and isolated the hum between the power amp and the
speakers. I have a Hafler TA1600 power amp. If I plugged one speaker into
the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

Does humidity in the air cause hum somehow? Can I get fancy speakers to
eliminate this? Or maybe my speaker wire shielding is bad?

The heat wave broke last night - humidity is back to normal for NJ. And the
hum is gone....

Thanks in advance,
bruce



Probably the mains got upset by some huge and abnormal load it
encountered during the heat wave - air conditioners flat out or
something. Still, this would not normally be expected to affect an
amplifier, which should cope perfectly well.

Just to be sure, did you disconnect all the inputs from the amp - just
switching them off doesn't stop ground loops.

As for speaker wire it isn't shielded, and doesn't need to be.

d