Re: How to quiet humming speakers?

TorbenGB wrote:

If you short both the tip and ring to the sleeve it should not buzz loudly.

You're right. I now unplugged the minijack and shorted all three parts
of it, and the humming WENT AWAY completely. When I removed the metal,
it started humming again.

Then I plugged it into my (cheap old) MP3 player instead. It still
hummed.
I powered the player ON. The humming STOPPED. It also didn't hum while
playing.
I stopped the player. No humming.
I powered the player OFF. The humming is there again.

That suggests that when the power is off the player presents a high
impedance, similar to no connection.

I unplugged the MP3 player. Still humming.
I plugged the speakers into my audio unit again, and now it doesn't
hum!

I also noted that plugging/unplugging the minijack in my audio unit
creates that brief, loud buzzing, but plugging/unplugging the minijack
in my MP3 player gave no loud buzzing.

Does this indicate a poor connection inside my audio unit??!

That it sometimes hums and sometimes doesn't suggests the jack in the
audio unit might be a bit weak -- these things have little pieces of
springy metal that make the actual connection, and they can sometimes
lose their springiness.

I hope not because it was expensive, but if so then I would get in
touch with the manufacturer (www.slimdevices.com).
I have several of these audio units, so I just tried swapping in
another one. Turns out it's the same there: when plugged in, the
speakers are quiet only if I wiggle the minijack a little, otherwise
there's a little humming. And WHILE wiggling it's making a buzzing
noise like hell.


Thank you all for your help so far! I hope you can answer this too.
-Torben

I'd suggest getting a pair of resistors of appropriate value (this will
depend on what the player is designed for, but something like 200 ohms
might be generally suitable) and putting them across the input of the
speaker amplifier -- unless, of course, you also need to be able to use
it with a high impedance device.

But before doing that, you might also consider another possibility --
are you sure the plug and jack are the same size? There shouldn't be
much "wiggle" if both the plug and jack are the same size. If they're
not, adapters are available.


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