Why so many Power plants for sale?

I had the PS 300 and then got the Hydra. Kept the Hydra and sold the PS 300. No comparison. Balanced power,voltage adjustment or not.....the Hydra is better even without these features. It is passive. IMHO

I have tried both the P300, Exact Power, and Equi=Tech.

P300. I think the P300 is a good product, especially at Audiogon prices--I have one up for auction now. Made a big difference in television quality and virtually eliminated noise from my CDP and preamp (the main culprits). As I stated in an earlier post on this subject, I think the reason so many come up for sale is that PS Audio has sold so many of them (a positive rather than negative reading on your observation). And the P300 is an entry-level unit so, after trying it, many upgrade to larger units.

Exact Power. I had a few concerns when I ordered this product given the lack of reviews. However, my experience is consistent with the review on the Exact Power site. I think it is a nice product which really does the job. You can hook up a lot of gear to it--far more than my circuits could deliver power for. I live in an apartment with poor power so it may bring greater improvements given my situation than yours. And my system is not overly power hungry so perhaps others can comment on any dynamic limitations this product imposes. One issue which I have heard raised is that downstream transformers may hum when attached to the Exact. I have heard this about the Power Plants as well so this may be common to power regenerators. I have noticed this with the Exact but it is quite minor.

Equi=Tech. Another nice product. Cleans up the AC well and generates balanced power. As you say, it will not adjust power voltage or frequency. A nice touch in my system following the Exact in the chain. But the Exact would get you most of the way there.

Good luck. --Scott

Power regeneration like on PS audio powerplants is good for low power sources but not for power amplifiers or expencive tube CD players or phono-stages since it doesn't have that capability to deliver enough power into. In fact it seems more and more not to have any use...

They're very good units, but are inefficient because they require so much power themselves that even the biggest ones really don't work on large power amps. I had to use a Richard Gray unit for those. Eventually it was just easier to get rid of both and switch to a Burmester 948 (expensive, but takes the whole system).