Using autotransformers

It has been suggested to me that the best way to avoid incoming voltage irregularities from the street to my Krell mono blocks is to add an autotransformer to each amp's dedicated 20 amp line.

It was also not recommended that I use ordinary voltage regulators because they reduce sound quality.

Have any of you had experience with autotransformers in your system? If so I would like to hear your feedback on this.
Often as high as 130-135 Volts and on other occasions it would drop to below 110.
04-28-13: Puerto

Your profile says you live in the USA.

If you live in the USA contact your power company. Power companies here in the US are regulated by the state. Most if not all require a max voltage variation of + or - 5% average, RMS.
120V being the base line. + 5%) 126V - 5%) 114V.

Now if you are experiencing low voltage at times in some parts of the house and high voltage in other parts of the house at the same time that is a horse of a different colour.
That usually indicates a loose service entrance neutral conductor.
I do not live in the USA. I now live in Mexico.
04-29-13: Puerto


You do have a few options.

* Sell the Krell mono blocks and buy amps with auto input voltage sensing.

* Install a Constant Voltage Transformer, CVT. Also known as a Ferroresonant transformer.

* Buy an Automatic Voltage Stabiliser, AVS.
Example of,
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Ferro-resonant transformers don't work so well for audio. They make a lot of physical noise and electronic noise too.