Voltage regulation


I have noticed that my dedicated mains power slowly fluctuates between 124 and 127 volts. Nothing seems to correlate like furnace - refrigerator turning on and off - time - day of the week etc. I'm looking for something that would keep the output a steady 120V without constricting the current. I'm not looking to break the bank but would like any and all suggestions.

The reason I'm looking for this is because I have a tube integrated where the bias goes up and down with the voltage fluctuations.

Thanks
xti16
Chuck It raises the output voltage by 3V. That pushes the output to 130V. Other than that the Topaz Isolates only. No regulation.
Hey Everyone Thanks for the responses. Any recommendations for a sub 1k budget limit (new or used).
There's some 5000VA/50Hz Sola MCR (works even better at 60Hz) on Ebay for $600. Heavy and expensive shipping. Insist on bolted/strapped to palette. These are noisy, so they have to be mounted remotely, if possible. The MCR is only 3% regulation but have much better CMNR than the CVS models. The SolaHD site has a technical/FAQ section that's educational.

Wouldn't recommend a tap-switching regulator for audio.
Do you hear the difference when the voltage fluctuates? Or you are concerned because you think it might do something bad to your amp etc.? In any case, I doubt that there is such a device for under $1k used that would consistently do it without polluting the current and/or restricting the dynamics. In the past the best audiophile devices of this kind were Accuphase and Burmeister, and they are probably still very expensive used. But even they may not be able to do what you want them to do on a permanent basis. The last time I saw Accuphase here, I think it was $2000 or so.
Some manufacturers have great voltage regulation built into their products. My Burson PI-160 integrated has their own in house voltage regulators and gone are the days when I had to listen at night to get the best out of my system. It sounds the same all day long now. I live in an apartment and the competition for power had its negative effects until I came across this Burson. They claim less than 1% voltage fluctuation and I believe it. I've never heard anything so sound good.
And clean.