No offense to anyone here who has spent a lot of money on the Monster conditioners, but I think they are massively overpriced wastes of money.
In regards to the AVS 2000 voltage regulator, it uses a large, variable transformer hooked up to a motor, and is only capable of regulating long term, slow changes in available wall voltage. If you measure your wall output and find that it is consistently well below 115V, then the hooking up the HTS 2000 may help. Unfortunately, it has absolutely no power cleaning or noise reduction itself, and should not be used with power amplifiers or large receivers because it is actually much slower to react to quick demands for lots of power than the wall outlet itself.
Monsters PLC's have moderate power cleaning and noise reduction ability, but at the cost of limited current output, so again, you cant use them with amps and big receivers. Source components may benefit a little (if your wall power is excpetionally noisy), but not enough to be worth the money. Neither is capable of fixing a clipped AC wave form, which is often the big problem when you are dealing with a situation of a large number of high drain devices hooked up to a circuit that may not be under your control. Surge protection is just the same basic MOVs that are in you're average power strip.
Shunyata Hydras and Chang Lightspeeds use basically a bunch of large capacitors in a box. They are not current limiting, and (the Changs at least, not sure about the Shunyatas) have the ability to break ground loops, which can be a nice bonus. AC noise reduction is better than the Monster stuff, but you are paying an awful lot of money for a bunch of large capacitors in a box. They also use basic MOVs to stop surges.
The Richard Gray stuff are parallel transformers, and the PS audio passive conditioners are series transformers. They'll both tell you that their method is better. I've tried them both, and I think the Richard Grays do a better job. Again though, neither can fix a damaged AC wave form. The only products that can do that are PS's AC regenerators, which give you perfect power and perfect 60hz (or 50 or 90 or whatever speed you want) waveforms. The AC regenerators can take the worst power imaginable and turn it into perfect lab grade power, but be aware that they are very expensive, and very inefficient because of the AC\DC\AC process. You get about half the wattage back out that goes in from the wall.
