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Topic: Plugging my audio equipment into my UPS (Read 7683 times) previous topic - next topic
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Plugging my audio equipment into my UPS

Follks,

I have an APC UPS (http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SUA1500RM2U&total_watts=50).  I have my amplifier plugged into it because i have the extra outlet to do so.  I've read repeatedly in various manuals that one should plug ones amplifier directly into the wall.

1. Why? What difference could it possibly make? Isn't the filtering on the UPS a good thing (if it does anything at all)?  As long as the UPS isn't overloaded it should be giving enough voltage/amps to the audio equipment just like plugging it in to the wall, right?


I'm a computer tech and i've had clientèle computer equipment fail due to brown outs and the quick off/on/off/on in succession that we get around here when the snow makes the power lines sag.

2. Couldn't this happen to my amp (it has a circuit board in it (a class-t) as well? So it'd be best to keep it plugged into the UPS?

Thanks.
Music lover and recovering high end audiophile

Plugging my audio equipment into my UPS

Reply #1 –
Quote from: BearcatSandor on
1. Why? What difference could it possibly make?


The output of a lot of those devices is often not all that close to mains power.  On older equipment this sometimes caused problems.

Quote from: BearcatSandor on
Isn't the filtering on the UPS a good thing (if it does anything at all)?  As long as the UPS isn't overloaded it should be giving enough voltage/amps to the audio equipment just like plugging it in to the wall, right?


Assuming its output is very good, yeah its probably comparable to what you get at the wall.  Otherwise, maybe not. 

Quote from: BearcatSandor on
2. Couldn't this happen to my amp (it has a circuit board in it (a class-t) as well? So it'd be best to keep it plugged into the UPS?


Probably not. 

Plugging my audio equipment into my UPS

Reply #2 –
some years back i read (comparision with proper measurements - sorry can't remeber where it was) that the output of an ups is not as good as one might think. it was even worse with a online-ups

Plugging my audio equipment into my UPS

Reply #3 –
You're probably better off getting an actual power conditioner, or just a good surge suppressor.
flac > schiit modi > schiit magni > hd650

Plugging my audio equipment into my UPS

Reply #4 –
well, this *is* a surge suppressor. That's what it does, and also provides back-up power by the same means. 
What would a power conditioner do that this does not?

@Saratoga: Why 'probably not'?  Why is the circuit board in an amp less vulnerable than in a computer?
Music lover and recovering high end audiophile

Plugging my audio equipment into my UPS

Reply #5 –
Quote from: BearcatSandor on
well, this *is* a surge suppressor. That's what it does, and also provides back-up power by the same means. 
What would a power conditioner do that this does not?


Neither of those things is likely to do anything. 

Quote from: BearcatSandor on
@Saratoga: Why 'probably not'?  Why is the circuit board in an amp less vulnerable than in a computer?


I have no idea what happened to whatever computer you're talking about, but a brown out is not going to damage an amplifier.

Plugging my audio equipment into my UPS

Reply #6 –
I deal with computers a lot, and have also built dozens of them throughout the years, and, that I can remember, haven't experienced hardware failure when the power is cut off. More likely, it's software corruption that damages the system.

Plugging my audio equipment into my UPS

Reply #7 –
Quote from: BearcatSandor on
I have an APC UPS (http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SUA1500RM2U&total_watts=50).  I have my amplifier plugged into it because i have the extra outlet to do so.  I've read repeatedly in various manuals that one should plug ones amplifier directly into the wall.

1. Why?


A number of reasons. One is that it is easy for a power amp to create a momentary load that may cause the collapse of the SMPS power supply inside the UPS and unnecessarily dump power for everything plugged into it.

Back in the days of laser printers, people were cautioned about plugging them into their UPS. They had heating elements that could momentarily draw a lot of power.

Also, you need to think about the purpose of a UPS which is delivering uninterrupted power. You no doubt know that that short interruptions are bridged by an internal battery. You know that batteries have limited capabilities. Therefore, it is common sense to put as few things as possible on your UPS so that its ability to bridge interruptions is maximized.

Quote
What difference could it possibly make?


Adding unnecessary loads can lead to self-induced power interruptions, or reduce the ability of the UPS to bridge momentary interruptions for equipment that needs to be kept alive.


Quote
Isn't the filtering on the UPS a good thing (if it does anything at all)?


The filtering in a UPS isn't why you bought it. Most people buy UPSs to bridge short interruptions. Do try to stay focused!

Quote
As long as the UPS isn't overloaded it should be giving enough voltage/amps to the audio equipment just like plugging it in to the wall, right?


Right, but the more load you put on the UPS, the shorter of an interruption that it can handle.  Handling longer interrupts is what most people are looking for from a UPS.

Plugging my audio equipment into my UPS

Reply #8 –
Quote from: BearcatSandor on
well, this *is* a surge suppressor. That's what it does, and also provides back-up power by the same means. 
What would a power conditioner do that this does not?


In general...

When the UPS is on battery, it will output a step-approximated sine wave.  Power conditioners used for pro-adio applications are designed to provide clean power, but do not have any backup power.  The do have voltage regulators, and will provide clean power to high current load devices.

Arnold - Feel free to correct or add to this.
flac > schiit modi > schiit magni > hd650

Plugging my audio equipment into my UPS

Reply #9 –
Quote from: indybrett on
Quote from: BearcatSandor on
well, this *is* a surge suppressor. That's what it does, and also provides back-up power by the same means. 
What would a power conditioner do that this does not?


In general...

When the UPS is on battery, it will output a step-approximated sine wave.  Power conditioners used for pro-adio applications are designed to provide clean power, but do not have any backup power.  The do have voltage regulators, and will provide clean power to high current load devices.

Arnold - Feel free to correct or add to this.


You're clearly on the right track. A UPS is not inherently a surge supressor, but putting good surge supression onto a UPS is a good defensive move on the part of the manufacturer.

You're also right about the output of your typical computer UPS not being anything like a pure sine wave. Usually, the UPS provides a stepped approximation of a sine wave which is just fine given that the computer has a very flexible SMPS of its own.  This brings up another point, which is that a well-made computer power supply provides quite a bit of inherent surge and sag control of its own.  These days so much audio gear has a regulated SMPS of its own that the requirements on line power are very relaxed.

I have installed literally 100s of computer systems and file servers. I rarely if ever put in a UPS unless some higher authority such as a vertical market software vendor demands one, and then only because its not worth the fight.  If the customer already is having problems with power outages then of course I put in the UPS but places in the midwest with problems like that are rarer than hen's teeth.  A UPS can lead to more system outages when the battery gets old or people start plugging stuff into it willy-nilly.

Plugging my audio equipment into my UPS

Reply #10 –
Thanks for the responses.

This UPS is a not a step-approximated sine wave unit, it's a pure sine wave unit. Also, this is a Class-T amp. If i *really* turn it up it past the level that i usually listen at it uses about 7 watts, according to a kill-a-watt that i've hooked it up to, so i'm not worried about *my* amp per se.

But this is useful info. Arnold, i never thought about that with regards to power amps and sudden draws of power. It makes me wonder why APC puts out a battery UPS designed for home theaters ( http://www.apc.com/products/apcav/index.cfm ). They must be protecting against that load somehow (stronger supply?).

Reading between the lines it seems that a computer will not be damaged by a sudden loss then gain of power, or a voltage sag.  Correct? What it is harmed by is a spike which would not be caused by a computer shutting off/on/off/on in rapid succession like can happen to the power out here.

I have a UPS because my power in the winter is less than awesome. I get outages multiple times a month. Sometimes they last fractions of a second and sometimes they last minutes or hours (once for 7 days) and i just want enough time to have my computer shutdown gracefully.  It's a linux box and i have it programmed to do so when the APC battery turns on for a set amount of time.

Thanks.
Music lover and recovering high end audiophile