Power questions

[Faux127]

I'm leaning towards the inverter type that was posted, but I'm weary that I won't have enough headroom

[sine143]

difference between 3kw and 6kw is 3db, 3db that your gear isnt even capable of extracting. *I* think you'll be fine.

[Grant Bunter]

Wait up guys,

Looking at amplifier output is only part of the answer!
Sure, you need to look at output because that dictates amplifier requirement.

You need to know the amount of power the amplifier/mixer/peripherals consume to produce that output, in order to decide the correct generator.

2 cabs/channel is most like 4 ohm load.
From:
http://assets.peavey.com/literature/man ... _26189.pdf

Pages 105 and 106.
Look at current draw.
The IPR II 2000:
Current Draw @ 1/8 power in watts: 185 @ 4 ohms.
Current Draw @ 1/3 power in watts: 425 @ 4 ohms.

& 3000:
Current Draw @ 1/8 power in watts: 315 @ 4 ohms.
Current Draw @ 1/3 power in watts: 735 @ 4 ohms.

Since, in terms of output, 50V @ 4ohms = 625W, that to me means you need to look at current draw at 1/3 power at least, because while output is never linear, amplifier power supply requirement increases in a directly proportional fashion.
So, for amplifiers alone, you require a minimum 1160W of output from your generator.
The power consumption of the rest of your gear should either be printed on the chassis or in the manual.

Next you need to look at any given generators cycle load specs. The trick there is to have a genny that produces the output required at less than 100% (simply because that's asking to much of the genny on a full time basis), but higher than the usual cycle load rating around 60%. This is so the genny doesn't carbon up in the engine. The hitch is, while you have to cover the higher rating when you're pumping the system, if you have a quieter gig on genny, you drop below the cycle loading. SO at the end of the gig, you need to turn up the revs on the genny to equate revs required for minimum loading for, say, 5 mins to de carbon...

edit, can't find any info on power draw for the amplifiers at more than 1/3 power, but that should also be considered, unless you want to do lots of math.

And when looking at reviews, I urge to to not just look at the amount of and star rating. The latest mentioned that the "regular" sockets had limited output...

[Faux127]

Wait up guys,

Looking at amplifier output is only part of the answer!
Sure, you need to look at output because that dictates amplifier requirement.

You need to know the amount of power the amplifier/mixer/peripherals consume to produce that output, in order to decide the correct generator.

2 cabs/channel is most like 4 ohm load.
From:
http://assets.peavey.com/literature/man ... _26189.pdf

Pages 105 and 106.
Look at current draw.
The IPR II 2000:
Current Draw @ 1/8 power in watts: 185 @ 4 ohms.
Current Draw @ 1/3 power in watts: 425 @ 4 ohms.

& 3000:
Current Draw @ 1/8 power in watts: 315 @ 4 ohms.
Current Draw @ 1/3 power in watts: 735 @ 4 ohms.

Since, in terms of output, 50V @ 4ohms = 625W, that to me means you need to look at current draw at 1/3 power at least, because while output is never linear, amplifier power supply requirement increases in a directly proportional fashion.
So, for amplifiers alone, you require a minimum 1160W of output from your generator.
The power consumption of the rest of your gear should either be printed on the chassis or in the manual.

Next you need to look at any given generators cycle load specs. The trick there is to have a genny that produces the output required at less than 100% (simply because that's asking to much of the genny on a full time basis), but higher than the usual cycle load rating around 60%. This is so the genny doesn't carbon up in the engine. The hitch is, while you have to cover the higher rating when you're pumping the system, if you have a quieter gig on genny, you drop below the cycle loading. SO at the end of the gig, you need to turn up the revs on the genny to equate revs required for minimum loading for, say, 5 mins to de carbon...

edit, can't find any info on power draw for the amplifiers at more than 1/3 power, but that should also be considered, unless you want to do lots of math.

And when looking at reviews, I urge to to not just look at the amount of and star rating. The latest mentioned that the "regular" sockets had limited output...

Awesome information Grant, thanks so much! I assume that the 2800 running watt generator will be enough power. If I'm only using ~50% power, then I can take the necessary steps to clean the genny at the end as you described. It looks like I'll be going with the smaller inverter type

Out of curiosity, why does it rate current draw at 1/3 power? Is that because most people don't just play sine waves all night, and actual music uses much less power than a 60hz sine?

[Bas Gooiker]

Don't forget to hook up a few par cans(bulb not led) to the genny aswell. To give it a bit of a stable constant load to compensafe for the big variations in power draw of the amps.

But i would really advise you to rent one from your local AV company until you can afford a decent one. Seen to much gear go bang on cheap "construction" type generators.

[Faux127]

Don't forget to hook up a few par cans(bulb not led) to the genny aswell. To give it a bit of a stable constant load to compensafe for the big variations in power draw of the amps.

But i would really advise you to rent one from your local AV company until you can afford a decent one. Seen to much gear go bang on cheap "construction" type generators.

I'm pretty sure I'll be going with the inverter type. I don't want to rent anything, my goal is to be completely self sufficient.

[Faux127]

Resurrection!


I've been emailing between manufacturer's (genny company, peavey) and it seems like the generator I was looking at (construction type) has AVR with an allowance of +/-5v swing. They pointed out that the generator puts out about 9% THD in the AC power, and questioned of my gear will accept that. Peavey referred me to a fellow who has operated a generator service, and he says that with the AVR on the genny, it should be fine, but I should be hooking up the sensitive equipment (driverack, mixer) through a furman or tripplite power conditioner with a voltage readout. This is where I get confused, as you guys all say that a furman power conditioner is a glorified power strip, which I was also under the impression of. So who's right in this situation? If the voltage is regulated well at the genny, as well as having plenty of headroom, will the power conditioner clean up the AC signal?

[Grant Bunter]

Resurrection!


I've been emailing between manufacturer's (genny company, peavey) and it seems like the generator I was looking at (construction type) has AVR with an allowance of +/-5v swing. They pointed out that the generator puts out about 9% THD in the AC power, and questioned of my gear will accept that. Peavey referred me to a fellow who has operated a generator service, and he says that with the AVR on the genny, it should be fine, but I should be hooking up the sensitive equipment (driverack, mixer) through a furman or tripplite power conditioner with a voltage readout. This is where I get confused, as you guys all say that a furman power conditioner is a glorified power strip, which I was also under the impression of. So who's right in this situation? If the voltage is regulated well at the genny, as well as having plenty of headroom, will the power conditioner clean up the AC signal?

Believe me, I feel your pain lol.

Well, lets look at what you've said bit by bit.

THD:
In order to decide if 9% THD is a problem because you're using a genny, you would have to compare that to typical THD in mains power. To get that figure, contact your power company.
Basically, if THD is twice that of mains power (as an example), and no given brand name generator is better than any other for THD, that's what you have to live with when buying a genny.
If it turns out that 9% THD from a generator is excessive compared to another brand of genny, then I would go for the genny with lower THD, or the make and model most similar to THD in mains supply.

Swing:
If the AVR genny you're looking at delivers 110V +/-5V, that's a possible +/- 4.5% swing.
Again, compare that to average (and extreme) swing with your power company mains supply figures.

Power conditioners:
The features on power conditioners are directly proportional to cost.
From what I can gather, base models don't voltage regulate, while the most expensive models do.
Since you're looking at a genny with AVR, do you need also need voltage regulation with a power conditioner?
ie do you need to regulate a regulated supply?

What most power conditioners apparently do is protect from voltage spikes (a problem associated with mains power and perhaps cheaper gennys), and clean up "dirty" sine wave supplies from EMI and RFI, and maybe non uniform sine output.
There's plenty of info on the net saying they don't do any of that terribly well.
And again, many EMI and RFI problems are associated with mains power and what another user/consumer is doing somewhere down the road a bit.
Not so much with a genny in the middle of nowhere!

As far as the voltage output meter, well, I guess it would be handy. Having said that, if you're at your mixer, picking the next track, cueing it, mixing it blah blah blah, or mixing a live band, really, how often would you get to look at that voltage meter?

Power conditioners might be handy for crappy cheaply built (to save cost) computer switch mode supplies, but IMO that's about it.

The final nail in the coffin IMO is that power conditioners also consume power to perhaps do what they supposedly do.

It's often been said that SMPS in class D amps are power sensitive. Others say that isn't the case.
I run old iron for subs and mains, SMPS amps for mons. None of that, nor my mixer or rack has had a hiccup on my genny, without a conditioner, so far.
TBH, I can't even tell most times where I use my rig on the genny, if my gear is running abnormaly warm or hot, as, invariably, the environment I am running my gear in has an ambient temperature approaching or above 100 degrees F. It seems no different to when I run on mains power.

While that situation is extreme, and may lead to premature failure of some components, I just take a teaspoon of cement and harden up to the fact that I may need to replace items down the line...

[Faux127]

So because I have the voltage regulation on the genny, then all I need to worry about is the THD in the AC, and it seems like power conditioners do nothing with that?
If I were to get a power conditioner, it would be a $100+ model, so I would hope that it would help the THD.
My electric company says the voltage swing for my house is +/-2v, so that's a little tighter than the 5v on the genny. They weren't sure of the THD, but they're going to ask around the office and call me back.

Awesome info, thanks a bunch. I'm hoping that the bigger construction generator will be fine because I don't want to have to buy another small inverter genny when I expand next year.

[Grant Bunter]

Nothing I could find says any power conditioner will alter THD.

I would think you would need the higher end, more expensive regulator type conditioners to maybe address THD output from your genny.

While a "brownout" isn't well defined, a 10% power sag or dip is thought to equate to brownout.
So, if you've ever had a brownout on mains in your area, your power companies figure of +/- 2.5% is errr, not believable. Ask them for extreme swing figures, as I think they've quoted you an average.

All in all though, don't just base your decision on purchase on price alone. If another genny has lower THD, as I said earlier, go for that. As I also said, if the THD is much the same across a range of genny brands and models, at similar pricing, so be it.
Buy once, cry once. If you're going to expand later, buy a higher KvA genny up front, and give it a good rev at the end of the gig for 5 minutes (with the power off) to de carbon the engine.

BTW, my genny cost me $2200AU...

[Faux127]

Nothing I could find says any power conditioner will alter THD.

I would think you would need the higher end, more expensive regulator type conditioners to maybe address THD output from your genny.

While a "brownout" isn't well defined, a 10% power sag or dip is thought to equate to brownout.
So, if you've ever had a brownout on mains in your area, your power companies figure of +/- 2.5% is errr, not believable. Ask them for extreme swing figures, as I think they've quoted you an average.

All in all though, don't just base your decision on purchase on price alone. If another genny has lower THD, as I said earlier, go for that. As I also said, if the THD is much the same across a range of genny brands and models, at similar pricing, so be it.
Buy once, cry once. If you're going to expand later, buy a higher KvA genny up front, and give it a good rev at the end of the gig for 5 minutes (with the power off) to de carbon the engine.

BTW, my genny cost me $2200AU...

Yeehaw that's spendy.
It's hard to spend a bunch for a generator for a PA that I'll be using only a few times a year, and mainly for free. The genny I'm looking at is more than double what I need, so I think I'll just go with that. I've had plenty of times where my power at my house would dim all the lights pretty badly, so I don't believe a nice generator like this one will be bad. It's not like it's a harbor freight model

[Grant Bunter]

About $600 of that cost was for the extended fuel capacity (It holds about 5 of your gallons and will run for 20 hours at above 60% load on that, 13HP honda engine).

I guess you have to add up the value to replace your gear if you blow it all with a "lesser" generator. What I spent on the genny is less than the value of my gear. I don't use my genny much either, but I need it to do some gigs where I am.

I always recommend amps on last, off first, but don't switch on everything you own at the same time when running on genny.
You can probably switch on everything else except the amps at the same time, but 1 amp at a time, with a 5 to 10 second pause between each amp, so the revs and output stabilise.

If the model you buy requires "running in" oil, or your first oil change is due at a limit in hours that is shorter than your first gig, stick 2-3 x 500W floodlights on the output and run in with that load for the recommended time and change your oil before the gigging.

I take it Harbour freight is not known for their quality products...

[escapemcp]

I run my rig off a 2.8kva 'construction' Genny (£180 from Lidl - Honda clone). This runs 2inuke 3000 amps - one running an Otop on each side and the other running the subs (2xT30 (50V lab12) a side) - along with decks, processors, lighting etc. It does this quite happily, although it does briefly lose revs when you turn the amps on due to the high inrush current.

I was looking at an inverter model myself, and found an article that mentioned if you are running purely SMPS (switch mode power supplies) on an inverter Genny, you should oversize the Genny by about 2.6 times to avoid it tripping out. You'd be well pissed off if the Genny tripped every time you turned an amp on as it would render it useless for amp duty.

And a final note.. Use the earth rod on the Genny... if it does develop a fault it then has somewhere safe to dump current, rather than through your kit.

[sine143]

didnt you say one of your inukes died recently escape?

that genny

[Faux127]

I run my rig off a 2.8kva 'construction' Genny (£180 from Lidl - Honda clone). This runs 2inuke 3000 amps - one running an Otop on each side and the other running the subs (2xT30 (50V lab12) a side) - along with decks, processors, lighting etc. It does this quite happily, although it does briefly lose revs when you turn the amps on due to the high inrush current.

I was looking at an inverter model myself, and found an article that mentioned if you are running purely SMPS (switch mode power supplies) on an inverter Genny, you should oversize the Genny by about 2.6 times to avoid it tripping out. You'd be well pissed off if the Genny tripped every time you turned an amp on as it would render it useless for amp duty.

And a final note.. Use the earth rod on the Genny... if it does develop a fault it then has somewhere safe to dump current, rather than through your kit.

The guy I was talking to was mentioning the ground rod, and ground fault extension cords. I think this genny will work fine. I don't have many gigs anyways, should lower my chances of gear frying