Ok, now a questions about power amps?

[CyberStrat]

I'm still putting together my new rack. right now I'm starting with just one amp, because that's what I can afford.

My question has to do with watts, price, quality. I really haven't looked too much because my local music shop talks like the Behringer EP2500 is quite a good amp for the $$$. My budget is no more than $400, and used is ok.

The crown 402 is 400watts @ 4ohm's. The behringer 2500 is 650watts @ ohm's. This is per side watts,

Anyway does the watts matter. Are we talking about clean power and more headroom in the Crown? In this example how will these two amp compare?

Thanks,

Cyber.

[Kap'n]

The four things that matter to me about power amps

Clean power at full bandwidth
Reliability
Minimum ohm ratings
Weight

I'm currently using a QSC RMX140 for mains/monitors, which is something like 275 W @ 8 ohms/side, 700 W @ 2 ohms, both channels driven. I wouldn't recommend anything with less power, but more would certainly help. It's all about clean headroom. Crown and QSC are the two major brands that are going to give you that, and reliability. I'd be less sure of what you're going to get with something other than those or Crest, or other quality brands.

If you never plan on using more than two speakers/side, a minimum 4 ohm rating is OK. 2 is always better, as you're less likely to run into issues, or you end up in a situation where you need that third or fourth monitor.

Weight. The RMX1450 is something like 26 lbs. Doesn't sound like much, but boy do I wish that I'd sprung the extra $100 for the PLX series. Half the weight. Some time when I get some extra cash, I'll buy a PLX or XTi, and keep the RMX permanently set up for practice, so I won't have to move it again.

[Spudman]

The thing about power amps is that certain ones do sound better than their cheaper counterparts.

A Mackie, Crown, QSC etc are going to sound cleaner than some other brands so that is something to look into. I haven't heard the Behringer amps but other brands that we have tried certainly do sound less clear than the three I mentioned.

For your budget look into the Mackie 1400. It's not too heavy, plenty of features for versatility and sounds good.

[juniorspecial]

Calculate carefully the amount of power you need.


Then triple that. That's what to buy.

[CyberStrat]

Can you tell me about calculating the power I need?

Right now we use to peavey PR15's and two peavey 12" monitors. 400 watts (800 peak) for the 15's and 500/1000 on the monitors. We will run the 4 ohm load on both channels, correct?

How much power should I be looking for? Is it bad to have less or more? How closely does it have to match up?

Cyber

[Offshore Angler]

The more the better. Crowns get my vote. They sound great and are reliable. Remember, once the power amp takes a dump the show is over. It's best to have two. Run the mains off one and the monitors off the other. If one craps on you, you can re-cable and limp through the job.

[Cygnus X1]

Woops.
I answered in the other post.

Crown , not Berhinger.

[chuckocaster]

i've only ever really used crown and qsc's, i've also used some REALLY high dollar amps, but that was only when i'd mix big outdoor festivals. i've never used a mackie power amp, but i think they should be fine, everything else they make seems to be pretty bullet proof.

like the others said, buy as much power as you can. pa sound is way different from guitar amps, you want as much clean headroom as you can get, and that means a lot of power.

[CyberStrat]

I'm quite confused understanding how large of an amp to buy.

My speakers are the peavey PR15's,"400 max program watts". I'm running them together for a 4 ohm load

There are two music shops in town and one is telling me I should have about a 400 watt amp, such as the crown XLS402 or possibly the 602, but it's not necessary. They have 450w and 600w @4 ohms respectively. The other store is telling me more like 800w like a qsc PLX1804.

So how do I calculate power for speakers?

Thanks

[Kap'n]

If you're planning on driving speakers to their maximum rating, you will want around twice the power that the speaker is rated to. That ensures you clean headroom. If the power amp distorts, it feeds square waves to the tweeter, and will burn it out.

OTOH, if you're not planning on driving the speakers all out, you can get away with less.

[CyberStrat]

Thanks Kap,

We'll I would say I'm not planning on drive the speakers wide open. The store that suggests a larger amp tells me with too little power, the speakers will burn out. Is that correct?

To do the math, do I just add the 400 watts from each speaker? Then that comes up to 800w with a 4 ohm load? Is that the amp I should be looking for for maximum speaker output.

One of the stores also says speakers are always over rated, that's why I don't need the larger amp.

Right now I'm leaning toward the Crown 402 or the 602, but the 802 is 800w @ 4ohm. My local store does a blowout on the 402 at $325, plus the rebate is going on now.

Cyber

[Kap'n]

The store that suggests a larger amp tells me with too little power, the speakers will burn out. Is that correct?

If the power amp goes into clipping, yes. That's the square wave thing I mentioned earlier.

[Mikey]

Me? I'd get the 602 with eyes towards picking up a 202 to run the monitors separately. That way you'd have plenty to run the mains, plenty to run the monitors, and the ability to switch off if the 602 blows up during a gig...not likely.
Right now, I'm running a 202 and a QSC 200 watter respectively and we're fine.

[Rickenjangle]

Yep, and we run 4 mains and 4 wedges.