Maybe newer PS Audio regenerators are much better, I don't know. Anyone compared ?Yes. The new ones seem considerably better. We could not run our gear on the older ones but we can now and they help out!
Now those German things look serious and they use safe chemistry for batteries. $30K ?One of our customers makes those- we had one at Munich about 6 years ago and it worked quite well. We used it only for the front end of the system- not the amps. It needed to be recharged every day, but it was on all day long.
They will have no effect on sound, unless you live in Texas :-), or at a place where power variations are more than 10%. In that case, instead of spending your money on those frivolous items, you should sue your power company anyway, to get better results. In this case, a conditioner is of no use anyway.. and maybe a regenerator may help, if it can keep the mains supply at a relatively stabe +/- 3% of what it is supposed to be.This statement is problematic- in fact, false. The things that affect equipment performance are distortion on the AC line and of course the voltage. The former is responsible for a variety of problems. The 5th harmonic (300Hz) is arguably the most troublesome. It shows up when a power transformer (like those big cylinders you see on power poles) get pushed past about 50% of their capacity. The 5th harmonic can be responsible for power transformer vibration, increased diode noise, synchronous motors wanting to turn in the wrong direction, stuff like that.
Fluke Instruments has published a number of articles on this topic. I'm sure they want to sell meters and the like, but they aren't targeting audiophiles! So this isn't snake oil- sheesh!
The other thing that can mess with toroid power transformers in particular is DC on the line (which can look like a 2nd harmonic)- usually caused by an electric heater running on half power (and so only using half of the AC waveform). The resulting DC can saturate the core of the transformer and cause it to rattle. Removing the DC is cheap and easy though; we build DC blockers into our equipment and you can get them easily enough as outboard devices.
If the efficiency of the power transformer is compromised (low voltage or 5th harmonic, DC on the line, and often, all three...) then the power rectifiers, which only turn on at the tops of the AC waveform for a few milliseconds, won't be able to charge the power supply properly. This is both measurable and audible. A regulated power supply can get around this problem if it has enough headroom, but regulating the power supplies of power amplifiers is difficult to say the least and therefore a rare thing to see.
So a power conditioner that actually does its job correctly is helpful for audio equipment. What I see as problematic is that most (over 90%) of high end audio power conditioners simply don't do their job- most of them are glorified power strips.