cpizey Posted July 10, 2012 Share Posted July 10, 2012 We're playing an outdoor gig and have been asked what spec of generator we need. Oddly we have never run off a genny before, and I know there can be problems. We have already had some issues where we have had to run off very long cable runs (voltage drop upsetting guitar preamps). As a stab in the dark I would guess that we need at least 10amps (240 x 10 = 2.4KW). Although we probably average much less than this I'm concerned that our power amps when switched on pull a LOT of power momentarily. Obviously we switch them on one at a time, but if the genny can't cope with the initial current in-rush, I guess we won't be able to switch on.http://www.blue-room.org.uk/public/style_emoticons/default/unsure.gif Our amps:2x Peavey 2600 - output 2x900W @4ohm1x Wharfedale 2800 - output 2x1400W @4ohm1x Omnitronic P1000 - output 2x500W @4ohm1x Hill DX 700 - output 2x350W @4ohm2x Mosfet 200W guitar power amps1x Hartke 300W bass amp Any advice will be most gratefully received. Thanks Conrad Link to comment Share on other sites More sharing options...
kerry davies Posted July 10, 2012 Share Posted July 10, 2012 Not sure about the equipment calculations as to what power you will be drawing but if 2-3kW is required I can recommend one of THESE! I cannot be specific about Devon but they are pretty commonly available. However! Your question assumes that the only things being powered are your kit and the generator is dedicated to you and no one else. If the real question is not what generator you need but how much power then all bets are off about speccing a genny until much more is known about what else they wish to supply. Link to comment Share on other sites More sharing options...
Stuart91 Posted July 10, 2012 Share Posted July 10, 2012 Make sure that whatever generator you hire has a voltage regulator. This keeps the voltage stable and prevents wild fluctuations which can damage equipment. Watch out for generators from the tool shop - they often only put out 220v to start with and that drops quite rapidly. Not a problem for festoon lighting or power tools, but electronics won't like it. Link to comment Share on other sites More sharing options...
timsabre Posted July 10, 2012 Share Posted July 10, 2012 Watch out for generators from the tool shop - they often only put out 220v to start with and that drops quite rapidly. Not a problem for festoon lighting or power tools, but electronics won't like it. Plus you have to position them about 5 miles away or the noise of the genny overpowers everything. Ask for a 100kva supersilenced set, then you'll be ok :) Link to comment Share on other sites More sharing options...
Brian Posted July 10, 2012 Share Posted July 10, 2012 Ask for a 100kva supersilenced set, then you'll be ok :)Only if the delivery driver remembers to leave you the keys! Link to comment Share on other sites More sharing options...
cpizey Posted July 16, 2012 Author Share Posted July 16, 2012 Thanks all for the advice. I should have mentioned that it was a small charity event - so with their (lack of) budget we weren't able to exert much influence.We did get a 6KVA, which had enough grunt for our power amps, but regularly upset our guitar pre amps and effects units, which kept cutting out intermittently and restarting.I guess this was caused by the voltage dropping momentarily. We have to endure a similar scenario next week, so is it possible to buy a 'voltage regulator'? What should we be looking for? - power conditioners may be? Or is this more UPS territory? Thanks again. Link to comment Share on other sites More sharing options...
TonyMitchell Posted July 16, 2012 Share Posted July 16, 2012 We have to endure a similar scenario next week, so is it possible to buy a 'voltage regulator'? What should we be looking for? - power conditioners may be? Or is this more UPS territory? Thanks again. Get a diesel set with automatic voltage regulation (AVR), this will ensure voltage stability, so as not to upset your sensitive electronic equipment. There are small sets available (6-10kva) with AVR modules, from the likes of Stephill, Hyundai, etc. The larger diesel sets tend to have AVR as standard. Link to comment Share on other sites More sharing options...
cpizey Posted July 16, 2012 Author Share Posted July 16, 2012 We have to endure a similar scenario next week, so is it possible to buy a 'voltage regulator'? What should we be looking for? - power conditioners may be? Or is this more UPS territory? Thanks again. Get a diesel set with automatic voltage regulation (AVR), this will ensure voltage stability, so as not to upset your sensitive electronic equipment. There are small sets available (6-10kva) with AVR modules, from the likes of Stephill, Hyundai, etc. The larger diesel sets tend to have AVR as standard. Thanks for the prompt response. We'll try and influence the organisers to get the a decent genny with AVR, but if we can't persuade them, is there anything we can buy for ourselves to 'smooth' the power from the genny? Link to comment Share on other sites More sharing options...
TonyMitchell Posted July 16, 2012 Share Posted July 16, 2012 Thanks for the prompt response. We'll try and influence the organisers to get the a decent genny with AVR, but if we can't persuade them, is there anything we can buy for ourselves to 'smooth' the power from the genny? I did some tests several years ago, with a 2200va APC SmartUPS, hooked up to a horrible little hireshop petrol genny, to track the voltage spikes. The UPS flattened the output, however the spikes were severe (<180v to >260v) and the UPS was furiously clicking away every few seconds as it detected under and over voltage conditions, which the software logged. Not wanting to ruin a good UPS, the part I didn't test, was how long the UPS would tolerate this input condition for. I ran the test for about 20 minutes. Link to comment Share on other sites More sharing options...
kerry davies Posted July 16, 2012 Share Posted July 16, 2012 Even charity gigs need to learn to do things properly or not do them at all. The question they have to answer is; are they prepared to pay for any and all damage to your equipment due to their cutting corners on generator hire? The question you have to ask is; is it worth the salt to have your gear ruined? Even if you went out and spent a fortune on UPS, not cheap kit, it may last a half hour and be ruined itself. Live in the solution not the problem, the solution is to start things off right, not build on the sand of poor foundations. (Free philosophy, must be getting generous in my old age.) Link to comment Share on other sites More sharing options...
cpizey Posted July 16, 2012 Author Share Posted July 16, 2012 Thanks for the prompt response. We'll try and influence the organisers to get the a decent genny with AVR, but if we can't persuade them, is there anything we can buy for ourselves to 'smooth' the power from the genny? I did some tests several years ago, with a 2200va APC SmartUPS, hooked up to a horrible little hireshop petrol genny, to track the voltage spikes. The UPS flattened the output, however the spikes were severe (<180v to >260v) and the UPS was furiously clicking away every few seconds as it detected under and over voltage conditions, which the software logged. Not wanting to ruin a good UPS, the part I didn't test, was how long the UPS would tolerate this input condition for. I ran the test for about 20 minutes. Kerry is of course right that its much better to start off right rather than deal with the problem, but its going to be very hard getting charity event organisers to get the point when there are plenty of other bands willing to take our place with no interest (yet!) in any of this. So given that its only a few of our low-current rack units that have been getting upset I was thinking of getting one of these to at least try and protect them: Zigor Ebro 650 UPS Thoughts?Thanks again.Conrad Link to comment Share on other sites More sharing options...
Brian Posted July 16, 2012 Share Posted July 16, 2012 Thoughts?That's a line-interactive type so will suffer the same problems as Tony documented above. The output's still not going to be pretty if the genny is ropey. Link to comment Share on other sites More sharing options...
kerry davies Posted July 16, 2012 Share Posted July 16, 2012 Sorry Conrad, we can't make it work but FYI;HSS, Exeter, 6KVa, super silenced, AVR @ £108ish. (I called, they have them.)Hire Station, Exeter, same thing @ £87ish (though details like delivery I do not know), plus if you want to run sensitive stuff only an IT specific 1.2Kw @ £37.There is a specialist company called Generatorhire (Doh!) in Exeter that hires gennies for events and weddings. They might even be open to requests for charitable discount since they are locals. You can beat a mule all day long but it will never become a thoroughbred. (More free philosophy!) Link to comment Share on other sites More sharing options...
greenalien Posted July 17, 2012 Share Posted July 17, 2012 Had a 6kVA diesel genny from HSS in Exeter last year for a party in a field near Honiton - it was crap, the voltage went down below 160V on-load, and it leaked oil everywhere. Luckily, we managed to get HSS to replace it just in time, and the replacement, which looked brand new, worked perfectly, drove a 2kW PA plus 2.5KW of lighting all night without missing a beat or dropping below 220v,.Moral - as soon as possible after arriving at the gig, put a decent load on the genny and check the voltage - easily done with a plug-in pass-through meter.NB - I have seen amplifiers get fried by connecting them to too small a generator - beware! Always work out the load, then get a genny with plenty of spare capacity! Link to comment Share on other sites More sharing options...
dbuckley Posted July 17, 2012 Share Posted July 17, 2012 If its just preamps giving problems then they dont need much power and alternative solutions are possible, like better regulated psu. Sure the 240v may be all over the place but the 12v or whaevever the preamps need can stay rock steady. Link to comment Share on other sites More sharing options...
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