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Digital mixer use with a generator.....?


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Hello:

I posted this question on another site but thought it would be best to post it here to seek additional advise....

 

I am providing the rig for an annual outdoor event next weekend.

The stage power is the same as per last year (I was told that it was). Last year's event organizer used a Predator 4000 (non-inverter) generator.

My Crown Itech/XTI/XS amps were fine as well as my outboard gear and Mixwiz.

 

I would like to use my QU-16 digital mixer this time around.....

 

Are there any issues using a digital mixer powered by a non-inverter genny?

 

Has anyone had any experience with this?

 

Mike M

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End result:

 

Hello All:

 

I ended up using my analog desk (Mixwizard) for the gig. The generator was indeed the one that was used during last year's event (Predator 4000). There were no negative issues.

 

Since the generator had two 13amp outputs I ran my TX4/9S rig with the above listed amp rack on one 13 amp circuit with the other going to stage lighting. No problems. There seemed to be plenty of (clean enough, I guess) power for the PA's needs.

 

Regarding the generator: The event organizer told me that the last time he used it was during last year's event. He didn't even use "gas stabilizer".... He only changed the engine oil after last year's use. "It started on the first pull...." Oh well, maybe he was lucky or the Predator generator was a good one.

 

The genny was a bit loud but since it was behind the "showmobile" it was not noticed by the attendees.

 

Would I get a Predator 4000 for my use? Maybe.... At a little more than $300.00 (which is cheap) I would use it for lights (not particularly sold on its use for a digital mixer) but used at a distance (50+ feet) from a performance area, it should be fine.

 

a note: The DJ was surprised at the amount of sound my rig put out on only 13 amps (liking my Crown amps at this time).

 

Let's see what happens next year.

 

Mike M

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I will refrain from making absolute statements outside my knowledge base but...............It is my understanding that some/most/all non-inverter gennies can also cause damage in a cumulative manner as well as immediate. The fact that all went well for your gear this time, and the next, next, next. does not mean your gear isn't taking a slow beating. As expensive as this stuff can be, I would suggest you consult with a subject expert (of which we have several) who can speak to this. As I stated earlier, I had two brand new class-D amps go down the very moment I turned them on with such power.

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I will refrain from making absolute statements outside my knowledge base but...............It is my understanding that some/most/all non-inverter gennies can also cause damage in a cumulative manner as well as immediate. The fact that all went well for your gear this time' date=' and the next, next, next. does not mean your gear isn't taking a slow beating. As expensive as this stuff can be, I would suggest you consult with a subject expert (of which we have several) who can speak to this. As I stated earlier, I had two brand new class-D amps go down the very moment I turned them on with such power. [/quote']

 

You do have a point. I should probably check with my amps' manufacturer (Crown).

 

Mike M

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Hey, Andy -- how good is the 60Hz these days in "big boy" generator-land? I ask because Hammond intonation (typically) depends on it. Nothing like an organ going flat when you turn on the lights!

 

Wes

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Pretty good, it depends on the calibration of the engine speed control circuit. Speed control is a fairly tricky feedback control system with all the usual tradeoffs. Fast, high gain response runs the risk of overshoot and oscillation, so it's critical that the governor be set up for critical (or overdamped) response.

 

 

 

One trick is to specify a higher than necessary capacity, then rely on the rotating mass and higher prime mover power to load ratio to improve dynamic performance.

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Pretty good, it depends on the calibration of the engine speed control circuit. Speed control is a fairly tricky feedback control system with all the usual tradeoffs. Fast, high gain response runs the risk of overshoot and oscillation, so it's critical that the governor be set up for critical (or overdamped) response.

 

 

 

One trick is to specify a higher than necessary capacity, then rely on the rotating mass and higher prime mover power to load ratio to improve dynamic performance.

 

 

The guys at Starsound specify diesel gennies only for flywheel/ crankshaft mass (among other things)

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Thanks. Interesting info. I'm always pretty wary of running Hammonds on generators, so far I have always managed to insist I get "house power" (sometimes with the aid of a 100' extension cord) because of frequency concerns. I only need about 3A and the equipment is completely isolated from the PA and stage, which mitigates most safety concerns. (I wonder if, in that scenario, it would be safer to have the organ's chassis ground lifted due to the possibility of a ground potential difference. The original factory design is two-prong, unpolarized plug feeding a single-insulated transformer...I check each power transformer for primary/secondary leakage when I acquire an organ, so far have none that leak more than a couple of volts).

 

Coincidentally, I'm working on a crystal-timed 240Vrms 50Hz sine generator specifically for Hammond run motors. This info tells me why products like that aren't a bit more common. If big-boy generators were as much of a PITA as the "trailer in a field"-gig generators I've dealt with in the past, I would expect every backline organ in the country to have something like that installed.

 

As for problems that can crop of with a diesel...a certain government agency with its HQ local to me found an interesting one during the ice storm of '98. Apparently you need to refuel them occasionally if you're running monthly tests...

 

Wes

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You do have a point. I should probably check with my amps' manufacturer (Crown).

 

Mike M

 

Well, I just got off the phone with Crown tech support. I explained the parameters (as per listed) and the tech told me that as long as the amps were working properly (without any drop-outs, etc.) the generator being used was adequate. I also asked him about the long-term affects on the amps powered by such generators and he stated that as long as the amps did not show any signs of stress (drop-outs, etc.) and was passing audio, all should be fine with no long-term damage to the units.

He started that if there were problems with the gen power, the problems would occur upon power-up, not well into use.

 

Let's see what happens.

 

Mike M

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Well Mike I'm certainly in no position to tell Crown they don't know what they're talking about so I won't. Considering the high cost of audio gear and the low cost of renting an inverter-design gennie like the Honda EU's, Yamaha's, Robin-Subaru's, why risk it ?

 

There are a plethora of gennie-powered-blown/damaged gear stories that may not have involved Crown products. Even if a manufacturer gave me a life-time guarantee for such use, I just feel better knowing I'm feeding my gear the safest, cleanest power I can. There are so many factors to worry about in a production, anywhere I can eliminate one I do.

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Well, I just got off the phone with Crown tech support. I explained the parameters (as per listed) and the tech told me that as long as the amps were working properly (without any drop-outs, etc.) the generator being used was adequate. I also asked him about the long-term affects on the amps powered by such generators and he stated that as long as the amps did not show any signs of stress (drop-outs, etc.) and was passing audio, all should be fine with no long-term damage to the units.

He started that if there were problems with the gen power, the problems would occur upon power-up, not well into use.

 

Let's see what happens.

 

Mike M

 

As somebody who has extensive experience with generators (and specifically the engineering behind them), I can say without a doubt that the guy you talked with is full of dookie. He may not know it, he may not even understand WHY there are such increased risks, but working as an engineer in the power distribution and system design industry (prior to and concurrent with my current work), there is absolutely increased risk, especially with all of the Chinese junk on the market these days.

 

Hey man, it's your gear. If you don't care about it's reliability, all the power to you.

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There is probably more truth to your statement than one may think.....

 

The tech that I talked to was young - ok, a kid. Kids (with degrees and all) do not have the experience that only "pounding the pavement" for years gaining e-x-p-e-r-i-e-n-c-e brings.

 

I have not doubted your opinion. I've just "dug around" a bit to see what others have experienced...... The tech, although meaning well, sounded a bit like my son who is currently attending a university in Boston as an engineering major....zero experience, but with all the answers.

 

How many times have we (as sound techs) started using a piece of gear "by the book" and adapted its use to what works best in a "real" situation?

 

When I started building my rig years ago and finally "graduated" to bi-amping my cabs I called a specific speaker company, talked to a "kid tech" asking how much power to drive the woof of the cabs. Mind you: full-range operation of the cabs (according to the owner's manual) recommended 800 watts @ 8 ohms for the horn/woofer combined. I ran the cabs full-range with this power with no problem.

 

When I went to biamp operation I called the manufacturer and talked to a "kid tech" to ask how much power I should give to the woofer alone. He said: "give the woofer 800 watts @ 8 ohms"...which I did....it sounded odd to me, but "they're" the experts. Two burnt crossovers later I reduced the power to 500 watts @ 8 ohms (I use Itech amps) per woofer and all has been rock-solid.

 

So much for that tech's advise. I got the crossovers fixed under warranty.....

 

Yes, an inverter generator would be ideal. I know that. I was just "kicking some tires" to seek information. I'll probably add an inverter generator to my bid for next year's event.

 

Thanks for all of your advise.

 

Peace.

 

Mike M

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I have been involved with the service end of this business for many years, I have seen the effects of gennys gone wrong. Really not good.

 

 

 

If you understand how a genny works, and how excitation fields work, you can easily see the potential for damage. Better gennys gave more robust control systems to prevent or limit such exposure to failure.

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I haven't had any problems running digital consoles on generators, but I've only ever used Honda EU or festival generators.

 

I'm very specific about the type of generator I require and have walked away from a few shows because the client didn't source the correct generator.

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