Need advice on juicing our amps

[luvpbass]

We just racked the four power amps we use for gigs. The rolling rack at the stage has a pair of Crown XLS 602s - one for the subs, the other for the mains, as well as a pair of Crown XLS 402s, with each powering a pair of floor monitors.

Our question is: The Furman strip we have, an RP8, has a maximum input of 1,800 watts. Can the four amps, plus a DOD 2 channel eq for the monitor amps, be plugged into this?

On the 602s, it says 1,000 watts right under the power chord plug. On the 402s, it says 1,300 watts. Is that the power the amp draws? If so, will this set up trip the Furman?

Also, when using the two 602s for the mains and subs, should the amp for the mains be set the same as the subs, or should it be turned down lower than the amp for the subs?

Thanks for any help you can provide.

 

[GregShadoan]

It could be ok, but when you pull all the current these amps can run you will blow the breaker. Power is IMO the most important factor in building/running a PA system. I would dedicated at least two (2) twenty amp circuits for this configuration. So no, your furman is useless.... to me.

 

[modulusman]

Smarter minds than I have said you do not need power conditioners in your amp rack. Here is the current draw for amps Invalid Link Removed I am surprised you havn't had any problems yet. If you ever push the PA hard it will probably shut down.

 

[modulusman]

Are you using a crossover? What are you using for PA subs/mains?

 

[luvpbass]

we use a crossover and the yamaha 1x18 subs are run bridge mono, as are the yamaha club series 1x15. the monitors also go bridged mono with two yorkville 1x15 on one amp, and a yorkville and passive hotspot on the other for the drummer. power shutdowns have been a hassle. we try run extension across the room in the hope of a getting the amps on separate power circuits but it's a crap shoot. My bass rig regularly experiences a lack of volume and tone due to puny power. it's the number one most annoying problem with gigging after "play freebird!" drunks and stairs cases.

 

[JackANSI]

I would have to echo GregShadoan's comments about using more than one circuit. (but you run a greater risk of buzzing with each new circuit you attach to.) Try to get some device to measure your current draw and try to balance it out as even as possible on each circuit. Once you get a pretty good balance though, just label things right and you should be better off than before.

I have one of these for that task: http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=AP7800 Doesn't show sharp peaks, but gives a pretty darn close estimation of when a breaker is going to pop. (got mine for ~$165 shipped on ebay)

Make sure you're using a nice big thick extension cord when you do go any distance over 12 feet. I use 12ga minimum over that length, its expensive, but required IMO. In the past I've bought cords meant for industrial uses that were 10ga and bigger and just cut and reterminated in the type of plug I needed. Just don't go crazy and put a 15A male and a 20A female and expect the circuit is going to do 20A. You just need the thicker cord to get the current to your rack with the least resistance.

Is this a PA you guys take with you all the time, or is it a semi-perm install in one location?

If it is a mobile one, you're pretty much going to be dealing with these issues with little to no chance of remedy. You can even try pulling some lows out of the subs and cut the infrasound on your crossover when in a real pinch for watts.

If it is a semi-perm install, see if the building owner will front the dough to put in 3 or 4 more dedicated 20A circuits at a minimum. Probably will end up being 2-3 grand if its done right by a professional

 

[modulusman]

By running your amps in bridged mono I think you are drawing more current than if you ran them in stereo.

 

[GregShadoan]

Power in small clubs/rooms are always a pain in the arse. Club owners rarly give a crap if your power is clean and installed properly. It is a huge problem, at least here in the US IME, and also can be dangerous. Then the added complication if you happen to be carrying a little lighting package around. Whenever I have to do something like this it always my first objective/question, where/what/how is the power. Your amps have the capibility of pulling 4600 watts, which is why the 1800 watt furman is useless for powering them up, unless you use 4 of them on their own circuit.
As I said before, you most likly will get away with using 2 dedicated 20 amp circuits, but even then, it might not be enough.

For example, most large touring PA's, have a 3 phase 90 AMP service in each rack, sometimes 2, getting power from a main distro, 200 amps is common. The good news is that most moderen amps are now switching power supplys, which can be run using much less (read green) power then even 2-3 year old amps. The industry is moving green faster than most. Even modern lighting is now (some) very low power.

The new crowns are in this catagory. The Itech series is an example of that. Although from experience, you still need 30 amps to use an iTech 8K for subs.
These are the guys most concert PA companies use. Invalid Link Removed

 

[walterw]

By running your amps in bridged mono I think you are drawing more current than if you ran them in stereo.

yep, that's the problem. you get more power into the speakers, but it has to come from somewhere.

bigger amps run stereo tend to not draw as hard as smaller amps bridged.