AC regenerator

AL, I have been enlightened many times by your thoughtful answers to many of these technical questions. I have read a lot about people running devices off of batteries to isolate them from the power grid. A couple of days ago I was thinking, why don't people use UPS back up power supplies for their equipment and just turn off or unplug the UPS before a listening session? Wouldn’t this isolate the components and create the desired effect? And what is the difference between a power regenerator and a UPS? Don't they both regenerate the AC?

Thanks,
Greg

Thanks very much, Greg. Those are logical questions, and yes, a UPS is a form of power regenerator.

However, for a number of reasons a conventional UPS would be unsuitable for use with an audio system. Those reasons include:

1)Some of them, especially the inexpensive ones, don’t generate pure sine waves. They generate a stepped approximation to a sine wave, which most likely means that their output has far worse harmonic distortion than is present on the AC that is coming out of the wall.

2)Limited run time. I have 900 watt/1500 volt-amp “pure sine wave” UPS's on a couple of my computers. Their specs indicate a runtime when on batteries of 11 minutes when loaded at half capacity, and 2 minutes at full load. My computer setups each draw about 200 watts when not doing heavy processing. The UPS that is on each of those setups will power them for less than half an hour when on batteries.

3)Lead-acid batteries, which are what are used in conventional UPS’s, don’t like to be subjected to large numbers of deep discharge/charge cycles. That will severely degrade their useful life, as I understand it.

4)I would be concerned about rfi (radio frequency interference) they may generate, which could couple into the audio system either via power cords or through the air. I’ve noticed that an AM portable radio will buzz fairly loudly when brought near my UPS’s.

5)I would also question how well they would respond to high speed fluctuations in current demand that power amplifiers (other than Class A) will require.

Thanks again. Best regards,
-- Al

Al,

I have also meant many times to express my thanks for your ever informative replies to technical issues, you are very generous with your knowledge..

Best Regards,
Ps

I guess I'm the only one who has not had an enthusiastic experience with AC regenerators. I've found restricted dynamics with it in my system despite reviews stating otherwise. However, it did clean up the sound.

What devices do users connect to isolation transformers, or filters, or regenerators? For example, with regeneration: digital, turntables, preamps, but not amps because of dynamics loss?

Power conditioning is in my to-do list. So far I only have 2 dedicated lines into 2 aluminum boxes housing good outlets and then good power cords.

Thanks!