Active subwoofer without hum?

[miepel]

Hallo,
I am looking for a new subwoofer. My older Sony woofer does a good job, but produces a disturbing hum with it's power supply. You can hear it on the back of the unit, while speaker itself is silent.
Is there an affordable active woofer, that produces no mechanical hum?
Rainer
PS: Please excuse my poor English.

[miepel]

I have tried another subwoofer (Mivoc Hype 10 G2). The hum was not that loud (toroidal transformer), but not quiet enough for me.

[Hoser Rob]

Try another cable.

[miepel]

The subwoofer is not connected to any source. When I connect it's AC plug, I can hear the mechanical hum from the transformer.

[ranchhand]

I have had that happen when the input plug on the subwoofer gets loose from the stress of the input jacks, and a tiny crack forms where the plug is soldered to the circuit board inside the woofer. If you lightly jiggle the input plug(s) you may hear a crackle and the hum stops. I took my subwoofer apart, re-soldered where the input jack connects to the circuit board, and that fixed it.

[miepel]

The hum is produced MECHANICALLY by the transformer. Do you know a subwoofer that uses a high quality transformer? I don't want to hear this mechanical hum any longer.

[Hoser Rob]

"The hum is produced MECHANICALLY by the transformer. "

I believe that'd actually be a buzz, not a hum. If that's what it really is ... get a new subwoofer. There may be another problem causing this, but that sort if thing isn't as easy to fix as web crap posts indicate, and you're talking about exposing people who don't know what they're doing to potentially lethal voltages.

Even transformers that are not especially high quality almost always avoid mechanical noises.