Most conditioners available to high end audio don't do a lot. The best of them is the PS regenerator, which really can deliver a proper sine wave.
The problem is it can't do a lot of power, although they are making some bigger units now. For the most part, we recommend to our customers that they plug directly into the wall as most 'conditioners' degrade the amp's performance.
The best conditioners we've seen were made by Elgar. These conditioners can deliver a low distortion sine wave right up to their rated current. The smaller conditioners do about 1000VA and the bigger ones we see do about 28 amps and so can run an entire audio room. They employ an enormous isolation transformer that is equipped with a feedback winding. A low distortion oscillator is used to produce a sine wave which is synchronously locked to the AC line, its output is compared to that of the actual output and an error amplifier applies the difference as a feedback signal to the feedback winding, while also at the same time bucking the isolation transformer so it also regulates the AC line voltage.
It thus eliminates spikes, harmonics of the line (the 5th being the most harmful and something that is very hard to eliminate), DC on the line and brownouts. THD of the output sine wave is typically below 0.2% at rated current. No conditioner offered to high end audio can do as well.
The problem is that Elgar got out of the conditioner market a long time ago, so their conditioners have to be refurbished. But customers of ours that have picked them up have been pretty impressed so it seems worth doing.
The problem is it can't do a lot of power, although they are making some bigger units now. For the most part, we recommend to our customers that they plug directly into the wall as most 'conditioners' degrade the amp's performance.
The best conditioners we've seen were made by Elgar. These conditioners can deliver a low distortion sine wave right up to their rated current. The smaller conditioners do about 1000VA and the bigger ones we see do about 28 amps and so can run an entire audio room. They employ an enormous isolation transformer that is equipped with a feedback winding. A low distortion oscillator is used to produce a sine wave which is synchronously locked to the AC line, its output is compared to that of the actual output and an error amplifier applies the difference as a feedback signal to the feedback winding, while also at the same time bucking the isolation transformer so it also regulates the AC line voltage.
It thus eliminates spikes, harmonics of the line (the 5th being the most harmful and something that is very hard to eliminate), DC on the line and brownouts. THD of the output sine wave is typically below 0.2% at rated current. No conditioner offered to high end audio can do as well.
The problem is that Elgar got out of the conditioner market a long time ago, so their conditioners have to be refurbished. But customers of ours that have picked them up have been pretty impressed so it seems worth doing.