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.