Outdoor gig - Generator power for amps.?

Chas Holman · Post by **Chas Holman** » 10 Mar 2001 5:24 am

We have an outdoor gig coming up - a fishfry out in someone's pasture. There is NO electricity nearby but they've offered to get a generator for AC power. Is it necessary to "condition" the AC power coming out of the generator for the apmlifiers and PA system..? I was thinking of using the APC UPS/surge protector unit, that I use for my computers, just as a precaution.

Blake Hawkins · Post by **Blake Hawkins** » 10 Mar 2001 6:00 am

Chas, wait until the generator is up and running and stabilized before you connect to it.
The power conditioner is fine to use.
If the band interconnects any equipment, be sure you use the same feed from the generator. Sometimes two different generator feeds will be referenced to different grounds or different polarities of the generator.
If it is a small generator you won't have that problem.
Blake

Lee Baucum · Post by **Lee Baucum** » 10 Mar 2001 11:10 am

It has been my experience that tube amps may tend to distort a bit if the amperage (I think it's the amperage) levels aren't consistant.

Lee, from South Texas

Chas Holman · Post by **Chas Holman** » 10 Mar 2001 11:52 am

Blake & Lee - thanks for the rapid responses. Do you think we could get away with coming straight off the generator..? Or should we definitely use the UPS to at least 'condition' the raw AC..? It's been my experience with computers that (direct) generator power is an absolute no-no. BTW - All of the gear is solid state.

Of course, my biggest concerns are really:

a) Wonder how loud we'll have to play to drown out the din of the generator's engine..?

b) Will there be enough cow patties layin' around so's I have something to level up the legs on the Sho-Bud...!

Danny Hullihen · Post by **Danny Hullihen** » 10 Mar 2001 2:28 pm

Chas: I've seen a lot of damage done to amps being powered by generators. Be exceptionally careful if you're using any digital equipment! Like computors, this is a big no.

Blake Hawkins · Post by **Blake Hawkins** » 10 Mar 2001 2:36 pm

Chas, It depends on the generator as to what kind of output you have and if it is clean or not. The waveform should be a pure sine wave,
If you have a volt meter, take it along with you and verify the voltage.
I did many television remote broadcasts using generators with few problems.
Well, we did have about $5000 worth of damage on one shoot when a young tech, who I had specifically told not to connect a second feed, did so after I left the site.
The producer called me one hour before the broadcast and told me all the cameras were smoking and had no pictures. I had to come up with three new cameras and rewire the power...but we made it. (the second feed had 220v where the ground should be.)
Find out as much about the generator they plan to use before you go.
I see no reason why you could not use a power conditioner. It would certainly give you some protection against spikes and overvoltage. Just be sure it can handle the current draw of the sound equipment.
Will this generator also be used for stage lighting? If so, you must be extra careful about the way it is hooked up.
Also if solid state dimmers are used, they can cause spikes in your power if you are on the same feed.
Some generators will cause a noise in sound equipment we refer to as "hash" the power conditioner would help get rid of that.
Any noise you hear in your equipment should be at a very low level.
Blake

<FONT SIZE=1 COLOR="#8e236b"><p align=CENTER>[This message was edited by Blake Hawkins on 10 March 2001 at 02:38 PM.]</p></FONT>

Bill C. Buntin · Post by **Bill C. Buntin** » 11 Mar 2001 7:52 am

It would be a good idea to check the speed of the machine before you guys try to run any sound equip. Lighting isn't generally too picky about gen. speed. By the way, the gen. speed determines frequency which needs to be of course 60 hz. I have a Onan in my motor coach. I have ran everything imaginable off of it with no trouble. Just make sure that you don't demand more wattage than the gen. can deliver. If its a small gen. like 5k or so, I wouldn't load it more than about 4500 watts. Give yourself a little spinning reserve. A better solution would be to run overhead wires from the nearest electric source. Course it may be too far away. What makes the portable gen. risky is that you are relying on one governor to control machine speed. So the integrity of the power is all in the engine governor's hands. Find yourself a Fluke digital multimeter. After you check voltage, then set that sucker on frequency, and watch the reading when you guys start firing up the equipment. Westinghouse and GE have always pretty much agreed that 59.9 hz to 60.1 hz is ok. if the frequency reading drops to below 59.8 hz, then turn off equip. until you get the freq. back closer to 60 hz.The ABS UPS is a good idea, but it won't gaurd you from a frequency problem. Surge protection is really kind of a myth anyway especially when you are dealing with a system that is an island like one generator and a load. If they are running lights, make sure the gen. has enough capacity. A few incandescent light bulbs would actually help to stabilize the machine. But if its real elaborate, a 2nd generator would be better. Hope I helped you. Just so you'll know, I play steel guitar as a sideline and hobby. I am an Operations Shift Supervisor at a steam electric power plant, so what I'm telling you about the little generator is the REAL DEAL. Regards