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Does anyone use or have any idea if computer UPSs are useful for audio mains conditioning and filtering? For example, using a UPS as you would a power conditioner from Tice or Wedge? If so, what would be a good VA rating to use. What brand, if any, would you recommend. I've seen UPS w/ 500VA ratings going for $80.
If I remember correctly....

If I remember correctly, the good UPSes are constantly running off the battery and letting the AC charge the batteries as long as there's power. So, the conditioning of a constant AC voltage is there, no dips or things like that. The problem is, and this is where things get fuzzy for me, in the shape of the AC waveform. in order to convert the DC of the batteries into AC, they approximate the AC waveform in steps, and its these steps that can cause problems. The waveform may be more consistent, but it can contain quite a bit more noise than before.

If you really want some clean power, why not figure out a way of eliminating the AC-DC-AC-DC conversions involved and run straight off the DC of the batteries. (If I understand the amp designs, they run off DC anyway) So the short answer is, maybe you'll get some better power, it depends on how bad your source is to begin with.

P.S. - Keep in mind, I'm not an electrical engineer, I'm a computer geek who's dangerous with a soldering iron.
Different Waveforms

The waveform coming from a UPS is often not a regular sine wave, but a square one. I've heard of this causing difficulties, although its been so long I don't remember the exact source of the criticism. While not exactly scientific, my monitor behaves strangely when powered by only the UPS, not the AC power cord. Buzzes, hums, and strange squiggles on the screen - these effects are minor, but indicate something a little strange going on...
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Ok, seems like their are more vote for not using one.

Then my next question would be which line conditioning systems for audio purposes is a good value? I think Monster Cable makes one now for around $250. Can anyone recomment any others?


Power Conditioners

I use one by Panamax mostly for surge protection. There is a little "conditioning" built into it, but not much... From what I understand, some of the better ones come from companies like 1) Tice and 2) Power Wedge. Each offer models with digital & analog isolation, dedicated outlets for high powered amps, etc. Entry level into these products is a little pricey - perhaps $200-300 for base models. Check out Audio Advisor for some descriptions and products. I believe they carry both Tice & Power Wedge.

Isn't this why we spent hundreds of dollars on filter caps and high frequency bypass caps? Isn't it true that our oversize transformers and filter caps act like huge resovours that will not charge or drain quickly in response to mains ripples thus filtering out all but a sustained change in voltage, which would result in a gain or loss in max power but not distortion? Would not the bypass caps on the amp boards filter out the rf noise? Am I over simplifying things or have I made a legitimate case?
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Well...the reason to use a line conditioner is to do just that, condition the power coming into the house. If you were able to see the wave form of a power outlets 50-60hz wave, it's very dirty. What the conditioner does, aside for cleaning up pops and RF, EMI and other interference is provide a clean AC wave form. Raising the voltage when there is a sag or lowering it if there is a surge. A power amp supply usually can't do this. (But somewhere there probably is one built by some krazy DIYer.) Line voltages don't stay at a nice 117-120 volts all the time.
I believe that the sound of your system starts to be effected even before the power cord.

So.. back to my original question. Can a UPS do this? From what the forum says, it's a big fat NO! A square wave is not like a Sine wave. That was all the answer I needed.

I did find one from Tripp-Lite that was inexpensive, but had only 4 outlets. But, I'm trying to make sure it is able to be used for Audio/Video apps. It goes for $80. Hopefully their info people will get back to me. If it does work, I will share it with you all.

[Edited by vdi_nenna on 02-01-2001 at 05:14 PM]
A UPS is a bad idea for audio use.
Unless it is pure sine wave, which I doubt. (99% of commercial UPS´s are not). If it is not 100% sine wave then it generates a lot of harmonics into your system which is worse then using the original mains.
A better idea is to use mains filters and a mains stabiliser.
The filters,that should be rated at high currents, take out the noise from your mains supply. So RFI doesnt get into your audio equipment.
These filters are low pass filters and are connected between the mains outlet of your house and the power plug of your equipment. The are designs for this, but even easier is to buy a ready one usually in a metal enclosure with solder tabs or with flat connector tabs.
The stabiliser keeps the mains voltage constant. Either if that is 117 Vac, 230, etc. They are usually a transformer (which also acts as a mains isolator) with multiple primary taps. For instance 200, 205, 210, 215, 220, 225, 230 etc. and secondary at 220, for Europe that is. These usually monitor the mains voltage and accordingly change the primary tap so the output is allways the same.
Line Conditioner

My primary objective in purchasing a "line conditioner" was not to remove the AC noise (which is a worthy goal - and very expensive at the retail shop...) was surge/spike and under/overvoltage protection. I used to live in Tucson, AZ where the power supply could fluctuate from 98 to 125 volts pretty regularly. Also, there was high frequency of lightning strikes during the monsoon season and frequent brown outs during the summer months due to heavy air conditioning use.

The conditioner would shut down all of the connected equipment when it detected anything "strange" going on with the AC line. There would be random times when all of a sudden, the entire system would shut down, and then come back on a few seconds or minutes later. Don't know for sure what it was saving me from (sustained over/under voltage or a spike...) but I do know that it worked. I'm now living in central PA, and the power supply is very stable, almost a round-the-clock 120 volts. The conditioner hasn't shut my system down since I left AZ...
Power Conditioner/Surge Protection

Hey Vince, I have the Panamax Max1000+ (I think). I'm starting to forget model numbers of some of my equipment... Can't say that I hear a difference with/without the filter, but it does protect against surges and under/over voltage. You can probably find them new for about $225-$250. There is one thing to watch out for, however, this model cannot be used with a DBS - it will filter out those signals.

Promitheus is right. A pure sine wave UPS is very expensive and inefficient by its own nature. Personal computer's UPS works reasonably well for computers (not all the times). It has to be very well filtered for audio applications.

A switched mode power supply might be better with batteries and AC mains input possibilities, but again the noise and harmonics are difficult to deal with.


Personally I would recommend a UPS - but only an Online Sinewave one and you can pick them up cheaply as surplus items ( down here in Aus anyway ) .Online UPS's only use the mains to charge the batteries and run the equipment off the Inverter only . Considering the quality of the mains these days ( especially if your close to anything industrial ) the sound quality can dramatically improve with a clean isolated mains source - besides it's the closest you will come to batteries without the huge expense. I bought six UPS's two years ago and sold two to friends . One who uses it on his audio system (Homebuilt Leach , Speakers etc) and says there is a noticeable difference...
Mind you it is overkill ( he bought a 2400VA unit )...

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