Computer UPS for mains filtering ?


Active Member

Posted on another forum but no replies so through I would try here.

Anyone tried using a computer uninteruptable power supply to condition the mains between the house ring main and the hifi components ?

Also to this end, Thinking of putting a 3000VA unit in the loft and running the outputs to select power sockets in the flat (for both my computers and hifi components). Anyone see any issues with doing this ??



Novice Member
This was suggested in the DIY Mains cable thread but apparently they produce the wrong shape waves, square rather than sine or something. Also expensive and VERY VERY heavy.



Active Member
Finally found it.

Will have to do some more reading up on it to find out what 'not suitable' means.

As for cost....I currently have 6 Cyrus units, TV, Sat, Video, HTPC.

Just to cable the 6 Cyrus units at £30 / cable (taken from other thread) I will be looking at £180. For a second user rack mount UPS (Compaq 2200VA 6 output approx £1000 new) which could go in the loft (if I could winch it up there :) ) I would be looking at around £175 + postage etc on ebay making it still quite close and negating the need to re-wire the flat and put the HiFi on its own ring main (as I have two fridges and just about every other electric device on one main).

The weight issue is a fair point, mind you I am not thinking of moving it around one settled so it is just the initial placement that would be an issue.


Standard Member

If you really want to use a UPS to provide the best quality conditioned power then you need to use a "double conversion on-line" UPS. This topology provides the best quality true sine wave held at 230V with 50Hz frequency also very precisely held.
It works by converting all the incoming AC into DC then rebuilding the DC back into AC at the output. Hence why it always has a perfect fully regulated 230VAC 50Hz sinewave with no spikes or glitches coming through. These UPSs act as line conditioners in addition to being a true UPS i.e. goes to battery when the mains fails.

The compaq you refer to is a "line interactive" UPS. A cheaper, but inferior topology. Line interactive UPSs have basic filtering at the input for spikes and surges and other than that merely pass on the input mains directly to the output. That includes any voltage variations and frequency variations. Some designs include a transformer that crudely regulates the voltage by stepping up or down the voltage when the input deviates beyond a certain percentage (typically 12%) from the 230VAC mains.
Line interactive's are only designed to work as a UPS when the mains fails and it goes to battery. With mains present they merely sit there waiting for the mains to fail.


What you haven't explained is WHY you want to condition your mains? Do you have lots of transients on it? Do you get short duration supply interuptions?
Surely you are not one of those fools who thinks the hifi would sound better with a better mains power supply input? This might just have been possible with old-fashioned amplifiers with crude power supplies and poor PSRR, but with todays designs it is utter nonsense.
Don't waste your money on such things - spend it on material to watch and listen - its what you bought the kit for isn't it?:cool:

Similar threads

Top Bottom