Do power conditioners help with unwanted hum/noise

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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Sean, thanks much for the tip. I have done a bit of research here and lurked eBay. The best kind appears to be what's called an ultra isolation transformer with very (high? low?) internal capacitance, on the order of 0.0005 pF. I have a 220V three-wire line (2 hot, 1 neutral, and I can run a dedicated ground) ready for use as the new audio circuit, so what I need is bucking and isolation.

I don't know if single transformers exist which can do both jobs, but that might be the ideal solution, if I could find it.

My problem is my relative ignorance in the domain. I can wire up a house and build an amp kit but I don't know enough to ask all the right questions of an eBay seller, or recognize that a tranny has the right taps by looking at it and its specs.

Could you possibly suggest a basic reference on the subject?

Tobias: You don't need a bucking transformer at all. You can simply use a 220 - 240 volt transformer and separate the legs down to two 110 - 120 volt lines. Personally, i prefer to keep all of the equipment on one leg of the 220 line, but there are those that have split them and never run into problems. Many of these transformers can be run with multiple taps i.e. 110/120, 220/240, etc...

The spec's that you quoted as far as capacitance and "ultra isolation" are right on the money. The only other real factor is current capacity. This would be the rating in KVA's. If you have a 5 KVA ( 5000 watt ) transformer and are running it at 220 volts, you can use ohm's law to tell you how much current it can sustain. Divide 5000 by the input voltage ( 220 or 110, etc... ) and you'll arrive at how much current the transformer can pass. As mentioned in other threads about this topic, i recommend staying below 60% of the rated capacity of the transformer if possible. That is, if your entire system adds up to 2000 watts of draw, you should have a transformer capable of 3 KVA ( 3000 watts ) at the very minimum. A 3.5 KVA unit would be better and closer to the ratio i described. Obviously, a 5 KVA would provide even more headroom with the potential for an even lower noise floor due to less noise induced by the transformer itself.

Hope this helps. Sean
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