I was just about to bite the bullet & shell out for one of  these units and then I read a couple of customer reviews on Amazon which put me off Oxxtron, so I'm now looking at APC, though I don't want to spend a fortune on it and don't really know the load I'm drawing.

My entire studio (DAW, Console, Outboard, Keyboards) are essentially all powered from one wall socket, though this splits out into a pseudo star system using several 6-way distribution blocks.

What's the easiest way to calculate (or measure) the total load on the system so I can spec a suitable APC UPS?

Thanks

There are special meters that can read in line current and that is the best way. Could you borrow one from any electrician friends you might know. Another is to add up all the power ratings of all your gear.

Do you really need to put your whole studio on the UPS? It's really only the computer and monitor that really needs it. If you have a failure then you only need those items running in order to do a save.

Unless you are wanting the UPS for power cleaning purposes. There are better units that do both the filtering and backup. Well here in Australia anyway. But I am sure there are the same devices in the UK obviously. Don't get an under rated one though, that is where you can go wrong.

I have my equipment - PC, Roland Octa Capture and a couple of small power requirement devices all on UPS.  If I were doing a recording session and only had the PC connected and got a short power glitch/dropout it could still interrupt a recording session if I only had the PC connected.

APC and Cyberpower seem to be the two main "consumer" UPS vendors here in the US.  

One thing to consider, thanks to the EU requirement, is that new/recent PC power supplies are "PFC" type.  Many PFC power supplies require either a true sine wave output from the UPS (when on backup battery power) or that the UPS has a less than 4ms switching time.  If the UPS does not meet one of those spec's many PFC power supplies will fail (will power off) when the UPS is switching to backup battery power.

Hi Jack.

The PFC requirement is indeed one of the reasons that the Oxxtron models fail (allegedly) so spectacularly.

Jeff, I head what you're saying about only running the pc & monitors via UPS. I justy like the idea of being able to flip one switch to turn the entire studio off.

Although thinking about it, I can still do this if I go from wall socket to 6-way block and running the ups from the block.

Hmmm. Lots to think about.

Bristol_Jonesey


I was just about to bite the bullet & shell out for one of  these units and then I read a couple of customer reviews on Amazon which put me off Oxxtron, so I'm now looking at APC, though I don't want to spend a fortune on it and don't really know the load I'm drawing.

My entire studio (DAW, Console, Outboard, Keyboards) are essentially all powered from one wall socket, though this splits out into a pseudo star system using several 6-way distribution blocks.

What's the easiest way to calculate (or measure) the total load on the system so I can spec a suitable APC UPS?

Thanks

If you're running everything off of one wall socket, then you can estimate how much power you're using simply by checking the breaker rating on that circuit.  if it's a 15A breaker (typical - some bay be 20A for household use) then you're using 230V X 15A = 3450W.  (NOTE:  I know that Colin is in the UK so his voltage is 230V, if you're in the USA your house voltage is 120V).
 
that will be a conservative estimate (more than you're actually using) because a) you're only using 1 wall socket and that breaker will cover more than just one  and b) you're not tripping the breaker (or at least you didn't say you were) so you're not using the full 15A yet anyway.

and by the way..."uninterruptible power supply" is a misnomer and is one of my pet peeves!  all consumer UPS's are NOT "uninterruptible" - check the specs - they all have a "switching time."  if you have to switch from AC to DC power converter then there IS an interrupt in the power.  it's not long enough to stop the computer from working, but it's incorrect to call it uninterruptible!  (this is not directed at you, Jonsey - this is directed at the consumer market who created this incorrect name).

True UPS systems run off of the battery directly, or from the battery thru the AC converter without switching from the AC of the incoming current to the output for the equipment connected to it.  but that scheme is too expensive for home and small business (consumer) use, so they designed a system which switches to the battery back up when certain voltage/current conditions exist on the incoming line, which is much cheaper and actually much more reliable for the battery (batteries have to be replaced on true UPS's more frequently than consumer "UPS's").

anyway - just ranting - not directed at you, Colin - just the marketing idiots who originally created these things. 

The rating of a wall socket does not tell you anything about how much power you are using. It is telling the maximum amount of power you can use. eg my wall socket is 240 V rated at 10 amps which translates into 2400 watts but I am only drawing much less than that. eg 400 or 600 watts or so. Just as a computer is also not necessarily drawing the amount of power the power supply is rated at. The power supply inside your computer is the maximum power it can supply and most often the computer will be drawing less than that.

The only way to do it effectively is to measure the current in line and you can do that with the correct device. Adding up the total power consumption on all your gear might bring you into the ballpark although some of those ratings might be in maximum power draw situations eg your active monitors going flat out but most of the time they are not. 

I don't agree with jcschild below re using more than one circuit.  Unnecessary if the total power consumption of your entire studio is well under the maximum you can draw from one wall socket. In fact for earthing reasons and earth hums it is better. But if I were running a 1000 watt radiator or similar I would definitely plug that into its own circuit.

Bristol I don't like turning the entire studio on with one switch. It is not actually a smart idea at all. Firstly you will give the switch contacts a serious workout every time you do it and that could wear out. Also everything coming on at once might create a power situation/surge that some things may not like or even get damaged.

I have got a power board connected to the one wall socket but with 4 switches on it. I have got my studio wired up to 4 circuits. My computer goes direct to 24/7 power and gets power all the time. I did design and build a power filter though which has a frequency response only up to and slightly above the mains frequency. I am sure that helps a lot. (I still power it off when not in use) That way even if all 4 switches are switched off (by someone else that is) and the computer is doing something important it will never get power shut off in the middle.

Circuit 1 feeds a spare extension cord now which is not used. Circuit 2 feeds the mixer and some basic important power feeds to to my laptop etc. Circuit 3 feeds a six foot rack with everything in it and circuit 4 feeds just the monitor system. That way I can turn them all on of course and sequentially but also I can leave stuff off that I may not necessarily use. eg to do a computer backup I don't need any circuits on or to just do some editing on phones circuit 2 only etc.. You will save power by switching parts of your studio on that you only need at any given time. Think about what things you actually need to do any particular job and put those items on the same circuit. It works very well. 

As far as the UPS thing I tend to think they are only really helpful if you in an area prone to power failures. If you are not you may not need it at all. The price of that unit also looks too cheap for me as well. I did some research on this a while back and found out the units that really work cost much more eg over $1000 for about a 1200watt unit but it was a serious quality unit though.

UPS' have been around for a long time.  I've worked in computer rooms with "UPS" systems since the late 70's.  They were called UPS systems then.  However, the commercial systems work differently from the small UPS systems that are marketed for PC's today.

The commercial systems have several sections in them.  The first section is a rectifier that converts the incoming AC to DC.  The DC does two things, it keeps the bank of C&D batteries charged and also feeds the DC to AC inverter (and thus AC output).  This provides complete isolation from the commercial AC power line (for noise, etc).  If the AC power fails or dips below a set voltage there is an "instantaneous" switch to the DC batteries for the DC power source.  I had a 400KVA, 480 Volt unit for my computer room.  The UPS was in the sub-basement of the building, my computer room was on the 10th floor.  I had a power room that had transformers that converted the 480 VAC to 240 VAC 3 phase and to 220 and 120 VAC for equipment.  The batteries for the 400KVA UPS unit were 120 1 Volt C&D wet cell batteries.  The Batteries would last for approx 20 minutes, long enough to do an orderly shutdown of equipment if needed.  However, most AC power failures were either momentary or less than 10 minutes so we rarely had to do a complete shutdown of the computer room.

1) running everything off one circuit never mind one plug is not good. you should have minimum 2 x 15 amp circuits (or 20 amp)

also depends on how much gear you have.

ideally you have 1 UPS for computer and LCDs and another for the rest.

Tripp lite is who i prefer or Ultra for the larger units.  APC is too pricey.

typical computer. 700W power supply, 2 x LCDs @ 75 watt each (really more like 25watts but safe is better)
so just for those items you need 850W UPS.  NOTE watts do not equal VA.. a 1000 VA UPS is not good enough for 850W..

also Brown outs/Dirty power are far more common and far more damaging than spikes. so you really need a line interactive UPS.
(this keeps the volts the same no matter what your power does..  well to a point of course.)
something like the tripp lite OMNIVS1500 its 940W.

for higher wattage than that the Ultra ULT33046 2000VA

its generally cheaper to buy 2 smaller UPS than 1 large one for more wattage than 1200 it gets really expensive.


you need to add up all the wattage of your items to find out.. just knowing your plug is 15 Amp dont tell you jack..
which BTW is only good for 1800 Watts

Jeff Evans


The rating of a wall socket does not tell you anything about how much power you are using. It is telling the maximum amount of power you can use. eg my wall socket is 240 V rated at 10 amps which translates into 2400 watts but I am only drawing much less than that. eg 400 or 600 watts or so. Just as a computer is also not necessarily drawing the amount of power the power supply is rated at. The power supply inside your computer is the maximum power it can supply and most often the computer will be drawing less than that.

The only way to do it effectively is to measure the current in line and you can do that with the correct device. Adding up the total power consumption on all your gear might bring you into the ballpark although some of those ratings might be in maximum power draw situations eg your active monitors going flat out but most of the time they are not.  

I do agree with this to an extent.  I merely offered an easy way to give a conservative calculation.  without buying a device to measure the power consumption, the next best way is to check every device you have connected and see what their ratings are and add them up.  this again, as Jeff says, is not the real power consumption, but is a maximum that it will use. 
 
however, this, IMO, is the best way to calculate for your "UPS."  since the device to measure your power consumption is only what your system is loading at that particular moment in time, it does not show maximum, average or trends.  calculating for the maximum (by adding max's of each device) would give you a number higher than your normal consumption, but lower than the "quick and dirty" calculation of volts X circuit breaker amp rating.