Who has Caps on their AC lines ???

You can purchase a multimeter or dedicated capacitance reading meter to see what value they are. If you don't want to do this, and can live without them for a while, you can drop them in the mail to me. I can read the value and return them back to you. You might also be able to find a local repair shop that can read the value for you.

I have been using caps on my AC for quite some time. It is a simple tweak that i've discussed here more than a few times.

As far as Iso's go, they are not all created equally. Many people use too small of an iso, resulting in less than optimum results. They then base their opinion of how well an iso can work on this less than optimum installation, passing on the negative experience to others.

In order to avoid this, i've always recommended buying an iso that was rated for at least twice the draw of all of your components. On top of that, you want to find a model that uses a VERY large core. You can find iso's of identical KVA ratings with wildly varying core sizes. As a general rule, the larger the core, the less likely they are to saturate under heavy load or large dynamic swings. Sean
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Benie: You want to place the caps near the input side of the iso's for greatest results. This reduces the amount of "muck" that the iso has to deal with.

After that, all you'll have to worry about is keeping the AC "clean" from behind the iso up to the component. This means running low impedance power cabling that is RFI / EMI resistant.

One could take further steps to improve the internal power supply of the components by adding increased filtering, snubbers on the rectifiers, etc...

Paying attention to system grounds and how they are implimented component by component can also help lower the noise floor. There are a couple of different grounding schemes that manufacturers use, some being more effective than others.

Obviously, one can go as "crazy" on this as they can afford to and / or spend the time on. If done in reasonable fashion and with some form of consistency though, the benefits are quite additive and beneficial in nature. Sean
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I am currently looking through Belden's online catalogue for something like this that also meets some other specific criteria. So far, i haven't been able to find anything that i'd recommend. Sean
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I should have clarified that the 250 volt rating that i previously mentioned was for the working AC voltage, which is different from the DC working voltage quoted for most capacitors. I agree that a higher voltage rating is better, as the 120 volt ( nominal ) rating of U.S. based AC systems is an RMS rating, not a peak rating. AC peaks will typically run at somewhere around 160 volts during normal use. Having said that, the peaks can be measurably higher than this, especially if one is talking about heavily distorted AC or spontaneous spikes and surges. As such, it is better to be safe than sorry.

As a general rule, a cap rated at 400 volts DC will typically spec at appr 250 volts AC. Going to a cap that is rated for 600 volts DC offers even more headroom, but at increased cost. For as much money as we spend on some of these other ludicrous and far less beneficial "tweaks", splurging for higher rated caps can buy a lot of peace of mind for not that much more money.

Musicfile: I've used Xentek and Topaz "ultra-isolation" units in the past. These are superior to their standard "isolation" transformers, as they typically offer appr 20 more dB's of common mode noise rejection. Having said that, even their standard models are typically far superior to a toroidal design, as they typically offer appr 30 - 40 dB's more common mode rejection. Just make sure that you choose a unit that is rated for well above the intended draw and that it has a "gonzo" sized core. The actual core size may be more important than the actual rating, so long as one is not trying to run the transformer at or very near rated capacity. Sean
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