Using a shore power isolation transformer at home?

Oil change every 10,000 kWh, as usual :)

Face,

Isolation transformer is to address the input transformer vibration that is caused by something in the AC. Fluctuations are to be addressed by that servo-regulated variac. Sorry, I brought another topic under the same thread.

Mrtennis,

It is hard to know remotely, but wrong volage is probably the easiest thing to detect, just measure it. If it is indeed too low, might be possible to demand your power company to fix it.

Why are they not the same, from the electrical point of view?

Thanks!

Ngjockey, thanks!

Can you please clarify what do you exactly mean by "grounded input"? Shortening the neutral THAT COMES FROM THE PANEL TO THE TRANSFORMER to ground? Why is that a good idea? I've never heard of doing that (I am not very experienced with "pre-receptacle" wiring and might be wrong here: when you take something right from the panel, you can, probably, assume that ground and neutral are, essentially, the same).

Let me ask two more questions:
First, is it a better idea to have 2:1 transformer, converting 240 to 120?
Second, is it a good idea to add "enhanced grounding" via some buried rod?

Thanks!

Thanks, that was very detailed!

I am planning to install a dedicated line, and I am comparing the possibilities. Right now I have two main issues with power:
(1) sometimes the power transformer of my amp hums much louder than it should, and some "fraction" of this noise even penetrates into the speakers;
(2) the AC voltage can be anything from 118 to 124.

The former I hope to cure with a dedicated line (probably w/o any isolated transformer to start with).

The latter (which probably does not affect the sounding too much, but drives me crazy when I want to set the optimal regime for the tubes in my amp) I plan to cure with Monster's AVS 2000 variac+servo (I am almost ashamed to use anything from those bastards, but it looks like these servo-stabilizers are their only product that does what it says and is priced adequately, if buying used).

To have a layer of protection just in case AVS 2000 goes crazy, I plan to put PS Audio's Duet between it and my tube amp.

Does this all make any sense?

Why not?

Voltage is unstable, and I want 120V sharp. Isn't a servo stabilizer the way to do that in a non-limiting, neutral fashion?

Just looked at this diagram from Monsters of their AVS 2000.

Probably, I will through away all pre-transformer filters, to make it even less intrusive.

throw away, I mean :)

Sorry, I forgot to tell what Monsters AVS 2000. Here is a photo: http://www.bukutronics.com/?p=54. Besides those "high voltage suppressor" and "radio frequency suppressor" (see here) which I will surely bypass before I use a unit, this is nothing but a variable transformer (variac) with a motor that rotates its pickup contact, trying to keep sharp 120V.

The Monster bastards charge for a new unit 4-5 times more than what it is worth; besides, they almost surely limit the current by their "suppressors". However, to buy such a unit for under $500 (btw, the variac is 3 kW rated) and to slightly mod it into something less limiting starts making sense, at least to me. Of course, this type of a device does not give an instantaneous voltage correction if something serious happens to the AC line (that is why I want a non-limiting surge suppressor from PS Audio after the variac), but what I have most of the time in my place is a "slow floating" somewhere between 118..225, which is driving me nuts! To give you an example: those fluctuations are wide enough to cause the filaments on my 45's to go all the way from the allowed minimum of 2.45 to the allowed maximum of 2.55. Wouldn't you find that annoying?

What you are saying about transformer vibration is right, let me tell you what I have narrowed it down to. Two important things: first, it happens relatively rarely, and usually at nights. Second, similar thing start happening to other electrical devices - at least, to the ones connected to the same AC line from the panel. What I have not done, unfortunately, was to check whether other AC lines from our panel suffer from this also - probably, will do it as soon as this humming happens again (btw, the hum is rare but very obvious, nothing to blind-test here). To conclude, what I know for sure is that the transformer vibration is caused by something that occasionally comes from the AC; what I do not know yet is whether the cause is inside our house or something outside.