Should i use a UPS on my ht system?

Chris Grillo · 07-25-2003, 08:52 AM

Hi, I have a older home and i was courius if a UPS would do any thing to clean up my system. More then that are there any advantages or disadvantages to using a UPS? do any of you guys even use somthing like this in your ht systems? Thanks

Bob McElfresh · 07-25-2003, 11:20 AM

No.

The UPS devices sold for computer systems are passive devices - they do nothing for the AC power quality. When they DO kick in, the output power is very rough (it is an emergency backup after all - intended to work for a few minutes). There is even argument that hooking a battery-charger into the same outlet as your HT gear is a noise-generator.

A Power Conditioner is different than a UPS. Those have mixed results depending upon how poor your AC service is.

Chu Gai · 07-25-2003, 11:44 AM

The age of your home notwithstanding, what sort of problems are you having?

Chris Grillo · 07-25-2003, 12:48 PM

I guess I was conserned that poor power quality may cause things like excess hiss or even do some damage to the rec's internal parts! how do i test the condition of power?

Chu Gai · 07-25-2003, 01:07 PM

well that may well be a matter external to your home. there are a couple of things you can do to get a handle on your outlets and wiring. Home Depot sells a circuit tester that'll test for miswiring...hot neutral reversed, ground not connected, etc. It's located in the electrical area and it's $4. Apart from that you could always get a recording multimeter from Radio Shack and what you could do is check your voltage. They can be set up so that they'll take voltage measurements at fixed intervals. That'd give you some idea of the voltage 'stability' (some nominal variation is normal and expected). Also I'd consider examining the exterior ground outside of your home. Look at the wire. See if it looks like it makes good solid connections and isn't frayed or kinked. If it is, it can be replaced either by yourself or a qualified electrician.
If you're presently getting hum, it may be due to matters apart from your wiring. This ought to give you something to do this weekend.

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Karl_Luph · 07-25-2003, 01:24 PM

Ya'll got me curious about something here. I've seen numerous pro-audio racks that use a Furman power conditioner and they make a more expensive model that maintains an even voltage to the equipment even if there's a significant rise or drop in the voltage at the wall socket. Can anyone recommend these kind of units for HT?

Brian Fitterman · 07-25-2003, 02:11 PM

That is a voltage regulator. Most if not all UPS's now are voltage regulators to some extent.

Most pieces of electronics now-a-days have a pretty good tolerance for voltage variences...but sometimes during peak power uses, like very hot summer days, the voltage gets pretty low on some lines. If you have alot of a single circuit in your house, this can add to that too. At that point it might become a danger to your equipment.

I had this happen once to me. We had alot on one circuit in my living room. When my system was in there and I had a B&K ref 30, when the voltage got below 105, the relays chattered and I lost the sound. This was not good. But I fixed it by running a dedicate 20 amp circuit. Even on the hottest days the voltage never went below 110ish.

Some places may need this kind of equipment, some do not. Next time there is a really hot and humid day (95+ degrees) measure the voltage in your plug...if its low, then you might want to invest in one.

BTW, APC and Tripplite make good voltage regulators for a fraction of the cost of the Monster and Furman ones. Plug a good HT line conditioner in one of those and you should be all set.

If you have seperates get two. One 2400 watt for the amps, and one 1800 watt for the rest of your stuff. Otherwise one 2400 watt should cover you.

Claude M · 07-25-2003, 04:47 PM

yup UPS is a bad idea for audio equipment, some not all UPS (cheap ones) have a square wave output that at best will cause a buzzing sound (harmonics in square wave).

Chu Gai · 07-25-2003, 06:26 PM

Sometimes even the ones that output a sine wave aren't so clean looking. See if you can get someone at whatever company to send you or point you to a link where they show you the AC waveform.

Kevin C Brown · 07-25-2003, 11:54 PM

Furman actually makes products for home theater use too:

http://www.furmansound.com/consumer/ref/

Chris Grillo · 07-26-2003, 01:17 PM

Thanks Guys !! I love this place

Emmanuel_L · 07-27-2003, 04:10 PM

I've looked at 3 of my UPS with a scope (and a differential probe) and the waveform is a pure sine.

I have

APC SmartUPS 700 (line interactive)
APC SmartUPS 1000 (line interactive)

Liebert GXT1000 (online)

The line interactive on battery mode (or in voltage regulation) have a little noise near the zero transition.

The online one is perfect all the time since the AC is generated all the time (stable voltage).

I would not use UPS with amplifier but with other gear, I literally see no problem (on higher end UPS).