Do power conditioners help with unwanted hum/noise

Gs5556 puts his finger on the problem that has just been solved for me by an isolation transformer.

Since home heating season began this year in Montreal (and electricity use went up), I had been getting a hum on my bedroom lullaby system (HK 930, Paradigm Titan) that made it unusable for me, no matter what the volume setting. Adding a CDP made it worse, doubled the hum volume. The darn hum went up and down in volume, like a prop-driven small aircraft buzzing the neighbourhood. (OK, it was hum plus buzz... ).

I found a small (250VA), very cheap isolation transformer on eBay and it has cut the noise down to a viable level, not gone, but slightly more than just perceptible.

My main system is on a dedicated line and I get the same hum there, but at a much lower level. I've put the transport on a Deltec 500VA hospital-grade isolation transformer and the results are so good that I intend to give the entire dedicated line similar medicine.

You may want to try this before you spend much $$$.
I had a sporadic hum that I thought was in the AC line. I ran a new AC outlet back to the circuit breaker but it didn't cure it. I discovered the cause by accident when I disconnected the cable wire from the back of my TV and from the wall to rearrange some wires. The hum disappeared completely.
It comes back every few months but I just disconnect the cable line and reattach. It must build up a charge over time. Worth a try.

Tobias: I'm glad to hear of your results. I've been advocating isolation transformers for several years now and have helped others find suitable models for their given installation. Lak and Psychicanimal can testify to the benefits involved and i'm certain that others can too. That is, when the iso's are properly selected and installed. You might want to do some further research on the subject in the archives before investing more money into various iso's as some surely work better than others. Some iso's are more prone to introducing problems into the system, both due to poor design and improper selection for the intended application. Sean
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There are some other solutions for cable connections--like the "magic box" or somesuch. If you think the hum might be system related (i.e., post power conditioner), could you try unplugging other components to see if it goes away?

Edesilva: The "magic box" is basically an impedance compensated isolation transformer and that is why they work as well as they do : ) Sean
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