Power Conditioners


I have been researching AC conditioners and the more I read the more I am confused. There are passive units such as the Running Springs and Velocitor and then there are the ones using transformers for "balanced power". Is one better for the front end and one for the amplifiers? Any info or opinion would be appreciated. Don
donaudio
if you can find a used accuphase ps-500 here in audiogon, this would be the cats meow. i purchase a ps-500 here in audiogon for $2800 and it was rated 10/10. This is an extremely good power conditioner. If you don't need more then 500w of power, then this ps-500 will be your last purchase for a power conditioner.
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Been using Richard Gray Power Company (RGPC) Pro 400 over 10 years w/o  issue.