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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => AC Power and Grounding => Topic started by: Tracy Garner on November 30, 2013, 10:13:46 AM
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I recently acquired a Honda 3000is generator and want to power a DJ setup (2xCDJ1000, DJ mixer, laptop) with a pair of SRX 718/712 and 2x ITech 8000. What is the suggested limiting I should use on the iTech 8000s to keep from overloading the generator but still provide enough power to the cabinets within reason?
iTech 8000
Ch. 1 - SRX712
Ch. 2 - SRX718
iTech 8000
Ch. 1 - SRX712
Ch. 2 - SRX718
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I recently acquired a Honda 3000is generator and want to power a DJ setup (2xCDJ1000, DJ mixer, laptop) with a pair of SRX 718/712 and 2x ITech 8000. What is the suggested limiting I should use on the iTech 8000s to keep from overloading the generator but still provide enough power to the cabinets within reason?
iTech 8000
Ch. 1 - SRX712
Ch. 2 - SRX718
iTech 8000
Ch. 1 - SRX712
Ch. 2 - SRX718
Crown specs show the 8000's pulling 8.3 amps from 120v to drive an 8 ohm load/channel, 14.6 amps to drive a 4 ohm load.
You can get an "extra" 3.5 amps from the 3000's if you use the twist-lock outlet instead of the duplex Hubbells. Max available ampage is rated at 23.3.
I have partnered with a buddy who owns another 3000 and invested in a yoking kit. We now can borrow from each other and get 50 amps to work with.
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I recently acquired a Honda 3000is generator and want to power a DJ setup (2xCDJ1000, DJ mixer, laptop) with a pair of SRX 718/712 and 2x ITech 8000. What is the suggested limiting I should use on the iTech 8000s to keep from overloading the generator but still provide enough power to the cabinets within reason?
iTech 8000
Ch. 1 - SRX712
Ch. 2 - SRX718
iTech 8000
Ch. 1 - SRX712
Ch. 2 - SRX718
If you keep the amps from clipping driving 8 ohm loads, I think you should be OK. The twist-lock outlet that Dick mentioned is a good idea - you can power one amp from the twist lock, and the rest of the system from the Edison receptacle.
Keep in mind that turning down your system 3dB cuts your power consumption in half.
I've run 2 IT12Ks from Dick's EU3000 for an outdoor wedding, and it worked fine for my moderate volume application. The ITechs actually have a fairly high idle current draw - my system of the two IT12Ks plus my GLD drew 7 amps with no audio output running, but after that, they're pretty efficient.
It would be worth testing this before gig day, and then make sure you're running System Architect to keep an eye on things.
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If you keep the amps from clipping driving 8 ohm loads, I think you should be OK. The twist-lock outlet that Dick mentioned is a good idea - you can power one amp from the twist lock, and the rest of the system from the Edison receptacle.
Keep in mind that turning down your system 3dB cuts your power consumption in half.
I've run 2 IT12Ks from Dick's EU3000 for an outdoor wedding, and it worked fine for my moderate volume application. The ITechs actually have a fairly high idle current draw - my system of the two IT12Ks plus my GLD drew 7 amps with no audio output running, but after that, they're pretty efficient.
It would be worth testing this before gig day, and then make sure you're running System Architect to keep an eye on things.
This is pretty helpful info. I looked around for other threads to try to get some insight.
On the iTech outputs, would you suggest RMS limit? Voltage limit? I usually run these things at factory default but it seems like there is some opportunity to use the limiters in this setup.
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I would use both, if you set the Rms limiter at around the program rating of your boxes and the peak limiter to keep you out of clip, you should be fine with your power draw. I would recommend trying it out before the gig. I have a friend with 2 it8000s and one of them does not like to run on a generator at all. The other is fine.
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I would use both, if you set the Rms limiter at around the program rating of your boxes and the peak limiter to keep you out of clip, you should be fine with your power draw. I would recommend trying it out before the gig. I have a friend with 2 it8000s and one of them does not like to run on a generator at all. The other is fine.
If you set the RMS limiters to that value, you'll *never* have limiting from them. While I can't divulge the exact settings I developed (work done for hire) I can say that the power threshold is well under rated power.
In JBL's VerTec presets they do not use the RMS limiters at all, only peak voltage limiters.
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This is pretty helpful info. I looked around for other threads to try to get some insight.
On the iTech outputs, would you suggest RMS limit? Voltage limit? I usually run these things at factory default but it seems like there is some opportunity to use the limiters in this setup.
I have not played much with the limiters, as I am using manufacturer presets, but I suspect Tim is correct. "Program" power has a significant crest factor built-in relative to true "RMS" power, so the speakers operating at "program" (whatever that means), will have an RMS power much lower - possibly as low as 100-200 watts. This is actually a lot of energy if you think about it - a 150w Halogen light bulb can get to 700-800°.
This is one of those scenarios that trying to calculate everything will be much harder than measuring it or just trying it. I would start with clip limiters, and if you get in trouble, back them off 3dB.