I have a digital amp with a switching power supply, the Teac/Tripath with extensive mods by VinnieR. I have never tried isolation transformers such as the OneAC or Powervar units, so I can't comment on them.
I got the Transcendent Sound Balanced Power Supply Kit which can be found @
http://www.transcendentsound.com/power_supply.htm The effect on my modded Teac/Tripath amp was incredibly positive. Just more of everything. There is a but. The switching power supply of the Teac or more to the point, its power chord seems to feed the EMI back into everything ganged with it. (So don't gang anything w/ it.)
The costs ($399 w/ shipping) are relative to the gains. Wayne @ Bolder Cables also offers a similar unit at a nearly similar price point.
The excellent BPT and Equitech units are generally greater capacity and offer the ability to keep devices separated so that one can't poison the others. The cost is commensurate with their performance.(high) Balanced power works at least w/ my digital amp, I have heard the huge improvement w/ my own ears.
I have another system w/ a Decware amp and Wright Sound pre/phono which are tube devices that run in A class and the gains when I tried the balanced power unit there were not nearly in the same league. However, an LCD TV running there showed huge improvement.
Will it work w/ the Sony? There is one way to find out.
DIY just seemed too much of an unknown to me. The Transcendent Sound or Bolder cables devices were professional engineered and that matters to me.
John Risch, the cable guru from AA, has plans on his web site for a balanced power unit which includes parts recommendations but I felt a bit squirelly about the lack of a safety net but others may be more adventurous.
