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Festival power questions

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invisibility View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote invisibility Quote  Post ReplyReply Direct Link To This Post Topic: Festival power questions
    Posted: 06 April 2017 at 9:03am
Hello. I'm almost done building these:

4 x TH18s loaded with 18LW2400 (1200W AES, 2400W program)
2 x SMT-212s loaded with 2 x 12MI100 (450W AES, 900W program), 1 x 9CP755TI (70W AES)

For the sub amp I have a SAE PWM13 (each 18LW2400 driven separately):

http://saeaudio.com/pqm-series/

For the mids I have a SAE PMX1450:

http://www.abeltronics.co.uk/amptesting.php?z=Lexon_PXM1450

For the tops I have a MC2 MC650:

http://www.abeltronics.co.uk/amptesting.php?z=MC2_MC650

(I also have a QSC RMX 2450 as a backup)

If you add up the watts it's about 8000W, plus a few computers and not much else. The Abletronics reviews review of the PM1450 and MC650 both say typical power factor for a toroidal amplifier (thouhg I don't know what number this is!). The PQM13 I don't know anything about.  

I want to take it to Nowhere festival in Spain in July. What should I specify in terms of generator capacity? At least 10kVA? I'm not expecting this will be an option, but would one 32A single phase be sufficent we didn't run everything at full power? Probably I can only get 16A cabling, so I'm going to need three phase, right? If I got a three phase to 16A single phase distro box I'd run the PQM13 on it's own phase and the other other amps on different phases, right?

Power outages are unfortunately a common occurance. Is it worth it trying to put the LMS (an UltraDrive PRO) on a UPS to avoid pops when the power comes or goes? 

Finally, if I want to try and run the rig off a domestic supply (16A schuko plugs) is it crazy to try and find two separate circuits, run the PQM13 off one and the rest of the the other? Obviously I wouldn't run it at full power. 

Finally, what do people use for measuring power usage? I have one of those cheap plug in things, but I don't think I trust it. I also have a clamp meter, but it's a bit of a pain - I'd have to make up special cables to expose the wires or something. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 06 April 2017 at 12:33pm
you should be able to run that off a 32A single phase distro. 10kVA is on the low side for the generator I would think. You also need to run some dummy load (~2kW) that will give some load to the generator at times the amps aren't drawing much current.

you will probably get away with a 16A domestic supply as the fuses are quite slow blow. just keep an eye out that your plug isn't melting. or turn the volume down a couple of dB.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Conanski Quote  Post ReplyReply Direct Link To This Post Posted: 06 April 2017 at 5:37pm
Originally posted by invisibility invisibility wrote:

If you add up the watts it's about 8000W,


That's nice but it doesn't matter unless your idea of music is non stop sine waves, and if that is the case will have to limit output to the RMS rating of the sub drivers or they won't survive... so again that big number doesn't matter.
Actual music has a mean(average) intensity level somewhere between 1/3 to 1/8 of peak so your mean AC power draw is gonna be 1/3 to 1/8th of peak, so believe it or not you could run this rig on a much smaller power generator than you think.. 4kw should do it. But... as already mentioned because music presents such a dynamic load to the AC mains you will need a dummy "preload" so to speak to keep the gen set operating at a higher level so that it can supply the peak demands of the audio system, so that has to be factored into the equation as well.


Edited by Conanski - 06 April 2017 at 5:38pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote shagnasty Quote  Post ReplyReply Direct Link To This Post Posted: 06 April 2017 at 5:37pm
I use one of these for little gigs :-


Just a cheap Chinese meter (I have these meters in my racks too) with a neon to show earth is good and pair of Powercons.

For a couple of pounds more you can get a meter with PF readout as well, which can be kinda handy (or sad if you run a lot of blade arrays)

http://www.ebay.co.uk/itm/Digital-LED-Current-Voltage-Tester-Meter-Electric-Energy-Power-Detection-W-/262850905938?hash=item3d33228752:g:S7kAAOSw8gVYAE9j

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Post Options Post Options   Thanks (0) Thanks(0)   Quote 4D Quote  Post ReplyReply Direct Link To This Post Posted: 06 April 2017 at 10:31pm
It is all about the voltage regulator on the genset.

The bigger the genset the better the regulation system.

Most fests the power guys will balance the phases. Ask for at least 32A sph.

If its a dedicated gen set 16k and upwards with a 20% static load is good, Sure you can get away with 6k or 8k but it can end with silence.


Spare amp & controller is a good plan with any festival genset scenario..
DMZ. "The bass was intense. Girls were literally running up to stand next to the subs"
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Post Options Post Options   Thanks (0) Thanks(0)   Quote mini-mad Quote  Post ReplyReply Direct Link To This Post Posted: 06 April 2017 at 11:53pm
Originally posted by shagnasty shagnasty wrote:


..i might have to make one of those... looks handy!
If it sounds like a gorilla is trying to escape, turn it down.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote invisibility Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2017 at 7:17pm
Thanks for the replies. I'll do some tests on a 16A domestic supply and see what the numbers say.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2017 at 9:45pm
Bear in mind that most of the meters will not show true current peaks and may mask the real draw of your kit.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote kedwardsleisure Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2017 at 11:20pm
a ready made decent meter will show instantaneous and peak watts, amps, volts and PF. They aren't expensive
K. Edwards Electronics Engineers

North Staffordshire

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Post Options Post Options   Thanks (0) Thanks(0)   Quote scottylaroq Quote  Post ReplyReply Direct Link To This Post Posted: 10 April 2017 at 1:08am
kedward got a suggestion of one? festival season coming up for us canadians too! and our common ac here is nothing to write home about.
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