Axiom Home Page Forums General Discussion Technical Questions Noise Filtering

I have a chance to buy a used APC backups power supply, at an extremely good price. I was wanting to run my 2channel system thru this to clean up the AC and provide surge protection and noise filtering. I know absolutely nothing about this stuff and the manufacturer(tech support) doesn't know if it will benefit me either. The unit provides "Full time multi-pole noise filtering : 5% IEEE surge let-through : zero clamping response time : meets UL 1449". This UPS is intended for computer use, and my question is would it work for audio? Thanks for any replies.

john,

It certainly shouldn't harm your audio, but you may not see any benefits. Do you have a problem with noise on your circuits right now?

No problems, just thought that it may benefit with better surge protection and noise filtering.

I use one (got it for $35) just in case of a power outage or power surge. This keeps my amp, my speakers and my sub well protected.

OK well here's my small amount of understanding regarding APC backups. The way that it provides surge protection is by feeding all the incoming juice into a battery, and then feeding your equipment off that battery. So when it says zero clamping response time, what that really means is that the APC unit will fry instead of your stuff (which is preferable, but not ideal.) Other units divert energy surges internally or else switch off for the duration of the surge. I am fairly sure that APC's just feed it into the battery. (And thus can end up quite fried.) They are designed mainly to provide a few minutes of power to computer users in the case of a power outage so that current work is not lost. It's good that it meet UL 1449, don't buy any "surge protector" that doesn't or you're essentially buying an expensive extension cord.

So in short, it ought to provide surge protection and power filtering just like it claims, it may not survive any serious power surge (read: lightning strike), and you'll be able to listen to music for a little while in the dark.

If you're getting a healthy discount, it's probably worth it if you want the protection. You can probably get something better designed to filter and protect in the same (retail) price range though if you are willing to lose the battery backup.

Ringmir:

The UPS feeds a battery (24v or 12v DC, depending on model, I have one that uses dual 12v in serial and one that uses dual 6v in serial) and uses a power inverter to get AC back off the battery to supply the equipment... the voltage clamping happens BEFORE the battery.

The UPS just acts as a cistern in a city... when water consumption is more than incoming, the extra demand is met by the cistern, and after the demand goes down, the incoming water tops up the cistern. UPS' still use the same shunting as any other surge protection device for high transient voltages.

Bren R.

Ok well it can't possibly be *zero* clamping time. The laws of physics being what they are and all it has to take time. To save your battery you need something on the order of nanoseconds. Do you know what the real clamping time is?

I can pick this one up for 20. but I read on the back of the ups that it has an input max of 400watts and that is what my amp by itself consumes, so I will probably pass on it.
Also I didn't really care about the backup portion anyway.
Thanks alot guys

Yeah with an input max of 400 watts it's clearly designed for the high-end desktop user. 20 bucks is an excellent price though, you might want to pick one up for your pc