amplifier power consumption

Look on the back of your amp.

The largest your budget allows. Even though the watts may be sufficient to run your amp, dynamics can still suffer.

have you seen this :

http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&productId=100625870&langId=-1&catalogId=10053&ci_src=14110944&ci_sku=100625870&cm_mmc=shopping-_-googlebase-_-D27X-_-100625870&locStoreNum=159&marketID=1

I would be hesitant to use even the 540W ups, without knowing the exact power requirements of your particular amp.

Here is a Cambridge integrated amp rated 75W/channel and spec'd for a maximum power consumption of 600W.

Here is a Creek integrated amp rated at 80W/channel and spec'd for 340W consumption at full power.

So the numbers can vary widely.

Also, I would want to derate the ups capability by a factor of 2 or more (meaning its rating should be twice the expected worst case requirement) to allow margin and to minimize the possibility of affecting dynamics.

Keep in mind, too, that some ups's, especially the inexpensive ones, put out quasi-square waves instead of sine waves. You would want to be sure to get one that puts out true sine waves.

Re the wattmeter that Riley linked to, I would question whether or not it will capture and display very brief peaks in power demand, which is what is important for your purposes.

Regards,
-- Al

To repeat Rog's response it should give the info on the back of the unit. Usually near the AC power inlet...

As Al said make sure the UPS puts out a true sine wave. SCRs will give you at best a 12 step wave (12 pulse). Cheapo Battery Back Up UPS a square wave, horrible for audio equipment.

The only true UPS units on the market today that I know of uses IGBT technology.
*Undistorted waveform (low harmonics)
*Fast switching speeds (100% step loads)
*No ripple DC (long battery life)

A True On Line UPS unit takes the AC incoming power and converts it to DC then converts it back to AC.

A True On Line UPS unit using IGBT technology cost quite a bit more $$ to buy than an SCR based unit.

Just to further Almarg's & Jea48's point re. ensuring that you buy a UPS with a true sinewave output - I understand that some friends bought an UPS that did not (i.e. output a sq. wave) & they were not aware of this & it fried the electronics over a short period of a few months.
So, be very careful of the output waveform. Most of the time UPSs are targeted to PCs that use switching power supplies hence it does not matter but to audio electronics sq. waves are bad news. APC has come out w/ an audio version UPS but I believe that it's not cheap.

Your best bet would be to buy a PS Audio unit OR a (Canadian) PurePower unit. The PurePower has a battery backup while I believe that The PS Audio units do not.

Rrog, my amp has been modified and puts out more power than it did in its original state, but i will look on the back of the amp anyway (hadn't actually thought to do that! duh!)

Riley - thank you very much - I may just go out and pick up one of those!

Almarg and Jea48 - I appreciate your advice as well (and will pay heed to your warning about the unit not measuring peaks).

by the way -

Stangely, a very good service technician whom i know suggested using even the CHEAPEST one by a company called APC (the unit that puts out 200w). He states that he has all his equipment (all tubes) ALL connected to it (amp, cd player, tt) and that it 'does the same job as the more expensive ones', therefore 'you don't need anything more'. I asked him several times if he's sure... and he insisted it was more than fine for my application.

His statements really confused me, to be honest, since it doesn't seem to make all that much sense to me. Then again, i'm not an electronics technician.

"The largest your budget allows. Even though the watts may be sufficient to run your amp, dynamics can still suffer."

I agree with Face. Amp that consumes peak 600W, like mentioned Cambridge, does not take 5A sinewave current but short narrow pulses of very high current (repeated 120Hz).

Strangely, a very good service technician whom i know suggested using even the CHEAPEST one by a company called APC (the unit that puts out 200w).

That is probably this model, at $49.99.

I believe that when ac power is present all it does is to pass the incoming ac to the devices that are plugged into it, with some degree of surge suppression applied to the ac. One of the documents indicates a total current capability for all of its outlets of 8 amps, when ac is present.

When ac power drops out, or drops to too low a level, the battery backup kicks in after a delay of a few milliseconds. That provides a stepped approximation to a sine wave, which will keep a 200W load powered for about a minute.

So for several reasons (lack of true sine wave in backup mode; lack of power regeneration; completely inadequate power rating in backup mode; and noise filtering which is probably either ineffective or not provided at all) you don't want to let that get anywhere near your audio system. :)

APC's much more expensive products that are intended for audio and video systems, which I understand to be generally highly regarded, are linked to here. And here (on the lower half of the page) are some comments by Kal Rubinson on their model S15.

Regards,
-- Al

thanks a ton, guys! i really appreciate this help.

Perhaps i was confused with what my techie suggested (although i doubt it).

I may just try one of the cheaper units from APC for now (since i can always return it) and report back here as to how it worked out for me.

One point to note is that i'm getting a bit of a buzzing coming out of my woofers, which the technician says is non-existent in his tests... apparently, my amp runs cleanly and well above spec. This is part of what led me to believe i need a UPS.

Further, I used to own two Blue Circle Power Line Pillows and every time i plugged one into an outlet, the breaker would trip. I'm not certain what that means about the power here, but i'm sure it's not good.

Any thoughts from anyone on that?

I may just try one of the cheaper units from APC for now (since i can always return it) and report back here as to how it worked out for me.

You may just damage your audio equipment......

Before you hook the cheapo UPS battery back up unit to your audio equipment I suggest you take it to your technician and have him do a bench test with a scope hooked up to the load side of it. Use a 150 watt light bulb for the load.

After everything is set up and the light is lit unplug the UPS from the wall AC power..... More than likely you will see the light flicker and get brighter for a split second. Then take a look at the sine wave on the scope..... That square wave could damage the power supply/s in your audio equipment.

I don't see the justification for needing a UPS. Do you experience frequent power outages or brownouts? For buzzing woofers, maybe you should look into line conditioning instead.

Face: Well, the situation is this: I used to own a pretty good setup (unison unico, rotel transport w/ msb link dac III with half nelson upgrade, variety of speakers including Neat mystiques, StudioLab Ref 1, NHT 2.5i). This setup sounded great w/ all speakers mentioned at my former residence.

Upon setting up in my new condo, the sound collapsed. Flat, undynamic, lacking in clarity, no real depth, thin/hard, lacking air. Further, every time i plugged in my Blue Circle Power Line Pillows, the breaker would trip, which raised a red flag right off the bat. However, since the condo was brand new, i simply assumed it CAN"T be a problem with the power.

I was told that, unfortunately, the wiring in newly built condos is done SOOO cheaply and in a shoddy way that i'm likely picking up all kinds of interference, not to mention experiencing power fluctuations. Further, I never had any buzzing coming out of my woofers at my former residence, then suddenly, out of the blue - buzzing out of the woofer cones at the new residence.

My tech said that these issues w/ my system could be the direct result of the power in my building, which is why he suggested essentially stabilizing the power flow by using a UPS. This was also suggested to me by a high level electrical engineer at my office building.

Regarding line conditioning, from what i've read, for the most part, line conditioning deadens the musical experience - and i'm trying to go in the other direction! What was suggested by both techies is that a UPS would be more effective...

At this point, i'm almost ready to bail on the system entirely and take up basket weaving, so i wouldn't have to worry about power, acoustics and setup.

It sounds to me like what you need is not a ups per se, but a power regenerator.

As was said earlier, some higher-end ups's will provide that function, by converting the incoming ac to dc, and then converting the dc to a clean 60Hz sine wave.

Something like the PS Audio Power Plant Premier will also do that, without providing the battery backup function. But a cheapo ups will not do that, as has been said, and also creates a risk of damaging your equipment if the ac drops out.

Also, I'm wondering if the buzzing might be due to a ground-loop issue, or to rfi pickup that is specific to your new location. Are you using the same interconnect cables as at your former location? If they are unbalanced (rca) cables, and if they are either significantly longer than the ones you had been using, or if they are a different make or model, that might have increased the likelihood of ground loop issues.

And if there are any nearby dimmer switches, try turning them off as they can introduce distortion on the power lines as well as rfi.

Regards,
-- Al

Hi again, Al

No, no new cables... cables are routed cleanly... standard cable with rca ends... no dimmers...

yes, i was under the impression that both these people were talking about a power regenerator built into a ups (or that all ups' were power generators, more specifically).

I also make a point to turn off everything - even shut off my fridge at the fuse box - just to to get the best sound...which ends up still being mediocre at best anyway.

Are you sure the buzzing is not due to a ground loop issue? The way to check it is with a ground isolator plug adapter (isolates the third prong). Your condo electrical system may not be wired or grounded properly.

Tonywise -

funny you should mention that. I was sitting around, trying to 'enjoy' some tunes the other night..fiddled around w/ the wiring a bit...Turned the amp off for a few moments and when it was turned back on, the left channel began crackling. Upon touching the volume knob to turn it down, there was a static discharge that made the left channel cut back in.

I talked about this with both an audiophile friend and an electrician; the audiophile mentioned the possibility of ground look, so i'm going to go grab a cheater plug and check things out. Beyond that, the electrician suggested lack of grounding in the condo and offered to check it out for me.

Something is definitely amiss and, after all your comments and my further observations, it seems as though i was originally barking up the wrong tree.

This is definitely an exercise of my patience. At least I have something to work with at this point.

Is there a way to calculate or estimate an amplifiers consumption with the specs posted by the manufacturer about it? I'm looking for a number either @ idle or ballpark consumption when it has a load. The reason I ask is that I'm looking at a Vincent Audio SP-993 amplifier but I can't power consumption specs about it. I went onto Vincent's site and couldn't find anything either. Normally I just use my Kill-A-Watt but where the amp is I can't easily go there and measure it myself.

Thanks in advance.

Haven't read all the responses but a UPS shouldn't be run at over 60% capacity. Even that is generalized for SMPS, not linear power supplies.