Audiogon member Blindjim has posted a detailed review of the Running Springs Audio Haley AC power filter ($1,400). Upon comparing it to the PS Audio Duet, the reviewer notes:
In contrast to the PS Audio Duet, which I am in favor of owning as I own two of them, the Haley leaps ahead in the degree of speed and flow the musical picture develops. There is more dynamic thrust, and pace to it’s tempo than that provided from the PSA Duet.
Read the entire review, then check out Blindjim’s system and other reviews.