How much amp can home/bar electrical handle?

Discussion in 'Amps and Cabs [BG]' started by Arranger, Apr 4, 2004.

  1. Arranger


    Mar 9, 2003
    I'd think that this has to be an issue some of the time, right?

    Do I have to worry about plugging a World 2.1 or a PLX 3002 into my basement electric, or into the community power strip at the local pub?

    I see the PLX 3002 needs 10A. I don't know what current the 2.1 would need, because it's not in the spec sheet. Is amperage the way to sensibly judge the available juice?

    Thanks for the course in safe wiring!
  2. BruceWane


    Oct 31, 2002
    Houston, TX
    Yeah, amperage is the thing you're concerned with.

    99% of the outlets you plug into are good for 15 amps max. Well, let's say they're wired for 15A, max. I've played a few dumps where the lights would flicker so much you would have thought it was a light show.

    The Stewart 2.1 ought to be fine with 15A. Any electrical device that requires more than that will have a different AC power plug. One of the flat terminals will be sideways, so you cannot plug a device needing 20A (or more) into a 15A outlet. I've heard that there are adapters out there, but I absolutely wouldn't use one. You'll probably flip the breaker pretty quick, and if the systems not to code (I suspect many bars aren't) you could cause a fire.

    There are power amps that require 20A, usually around 3500 watts and up. The Crown Macrotech 3600VZ and 5000VZ come to mind, and they have the appropriate plugs to match. I thought about using a MA3600VZ in my rig, but decided not to because of that. Unless you or your soundman have a power distribution box, you're not gonna find a 20 amp outlet in a bar. Then even if you do have a PD box, half the time the breaker box has no available space to hook the thing up.

    That said, it's not a bad idea to have some surge protection on your equipment. One of the basic units from Furman will do fine. Don't bother with anything more expensive than 100 bucks or so, maybe a little more if it's got rack lights. For your use, anything more is overkill.
  3. JMX

    JMX Vorsprung durch Technik

    Sep 4, 2000
    Cologne, Germany
    Come to Germany - 230V and 16A ;)
  4. Arranger


    Mar 9, 2003
    I welcome the thought, thank you! :hyper:
  5. whats the use for so much juice in a bar or in your home?
  6. Arranger


    Mar 9, 2003
    You're certainly right. But, if it's the only amp I have, I'll need to use it everywhere. It will actually double for a variety of uses.

    Thanks. Any other replies?
  7. Munjibunga

    Munjibunga Total Hyper-Elite Member Gold Supporting Member

    May 6, 2000
    San Diego (when not at Groom Lake)
    Independent Contractor to Bass San Diego
    Lessee ... QSC PLX 3002 requires 10 amps. That's correct ... for one-eighth power pink noise. If you're running it bridged at four ohms and take it up to max power output, that'll be, ummm, lessee ... 3000 watts divided by 120 volts gives 25 amps! Now, that'd be your output current. Depending on the efficiency of the amp, the input current's gonna be a bit higher.
  8. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    Although, unless Arranger has a very big basement or a very large local, I hope he is not putting out 3000W :eek:
  9. Steve


    Aug 10, 2001
    You're amp is going to have to sustain that kind of output long enough to cause the bi-metal strip in the circuit breaker to heat to the point where it trips.

    Your wife, your neighbors or the bar owner will have their hands around your throat before that happens.......
  10. BruceWane


    Oct 31, 2002
    Houston, TX
    Technically, that's true. But the only way you're going to drive that amp to put out 3000 watts continuous is with a tone generator. You won't do it with typical music, and especially not the signal from a bass alone.

    Munji, I'm pretty sure that you know what pink noise is. For those of you that don't, it's a signal that has ALL frequencies in the audible range, 20Hz to 20Khz, in equal proportion, all at the same time. It's used for calibrating speaker systems and testing amps. Only. It sounds like a big, thick hiss. You've probably heard it at a few concerts before the show starts. It's used to EQ the PA system to the response of the room; since an arena full of people has significantly different response characteristics than an empty one, the sound engineer waits until the seats get filled to EQ the system. You're never going to be running anything like pink noise through your bass rig. Maybe if you're using a bass synthesizer you might come close, but if you're into that kind of technology, you probably already know all of this and how to deal with it.

    Unless you're running a compressor on a totally extreme setting, you'll never hit peak wattage for more than a millisecond or two. Not a problem. The distortion you'll get on the attack of the note will be enough to warn you to back off. Of course, if you happen to like the sound of a solid state amp that's clipping, I could be wrong, but that kind of distortion isn't tolerable even in the most hard-core industrial music.

    Again, any device that will require more than 15A in typical usage will have a different AC plug. If you do stupid things like continuing to push tha amp when things sound very, very bad, you will trip a breaker. Typical usage does not include stupid things like cranking it 'til it smokes or throwing it in a full bathtub.
  11. And that's about everyone in WV and a lot in PA and OH. The amps weren't what blew the breakers, it was the lights.
  12. Arranger


    Mar 9, 2003
    Yea, that's what I thought. I would throw it in the tub FIRST, and then watch it smoke. :cool:

    Thanks for the thorough reply.
  13. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    I have had difficulties in the past with this very issue. My prior amp, an Audio Centron RMA-1600, drew 20A, and I would blow circuits (in home and bar settings) on a regular basis. Suffice it to say, it was a PITA. However, my PLX 3002 in addition to being far more powerful (and much lighter!) has not had as much of a problem, though it still has tripped circuits a couple of times. Definitely avoid having your stage lighting and any amplification on the same circuit, or you will blow them for certain. Ideally, if you have sound support, and if the bar provides for it, a dedicated 220 line, with 110 stage power provided by the sound tech, is the way to go.

    But FWIW, I have used my PLX 3002 in my home on numerous times with no problems at all (though the RMA-1600 would blow circuits in the same setting).

    Good luck, Tom.
  14. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    FWIW, I have a QSC 3002 and an Eden Navigator preamp,Korg tuner, and effects pedalboard that all go through my Furman PM-8 conditioner which has a meter for both volts and amp draw. The amp draw while playing pretty loudly stays around 2 to 3 amps, and occassionally flickers on 4 amps draw. If the whole rig doesn't draw but 4 amps when driven, there's no way the QSC alone can draw 10 amps just by being powered on with a normal load.
  15. Arranger


    Mar 9, 2003
    So, it's only on power-up that the major draw will occur?
  16. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    While the circuit breaker's handle will be marked 15 or 20 A, it's only rated for carrying 80% of that current, i.e. 12 or 16 A.

    Like GreyBeard wrote, it's the lights that cause the problems, because the current that they draw is continuous.
  17. There is another factor that you need to consider with high powered amps, - the design of the power supply.

    The older ones used large transformers in their power supplies, and when you powered them up, the split-second current-surge to initially magnetise the transformer core was the thing that took the house fuse out.

    More modern amps have slo-start power supplies that do not have the switch-on surge. This may explain why some people have problems and others don't.

    With regard to the comment on running sound on the same circuit as the lights, you are likely to get a buzz on the sound system, caused by the dimmer circuits. Your best bet is to use a longer power cable and try to plug into another circuit elsewhere in the hall/bar/building
  18. Petebass


    Dec 22, 2002
    QLD Australia
    Or beter yet, ask if they've got 3 phase power. If so, use it to run the lights and run the sound off the power outlets. Or run a 3 phase splitter and put the lights on and sound on a seperate phase.

    If worse comes to worse and you have no choice but to run lights off the same circuit as the sound, you're best bet is the scale down the light show. If possible, run some sort of lighting mixer or chaser so that all of the lights aren't on all of the time.
  19. Jerrold Tiers

    Jerrold Tiers

    Nov 14, 2003
    St Louis
    Not surprising. That's the difference between ordinary and higher efficiency amplifiers.....

    The RMA 1600 (designed in about 1985) is a standard traditional single voltage type power amp. Those, of any brand, will always draw more power than a higher efficiency multi-voltage-level type such as the QSC you mentioned.

    Multi-level type amplifiers are most efficient at low and medium output levels, dropping lower at full output (relevant mostly for PA subs in discos).

    Class-D will be 90 to 97% effiicient from around 1/10 power up to full output.

    A standard single-supply amplifier will be 30% efficient (or so) at lower levels, and theoretically top out at close to 70% on a sine wave, although you generally can't get that good. Figure 50% on average.

    Most all types drop in efficiency as they get to the lowest load impedance that they are rated for, and are most efficient at the lighter loads.
  20. Ericman197


    Feb 23, 2004
    Chances are that you're never going to need all that power, and if you do, you'll have the right equipment to deal with it. For home practice and bar shows, you don't really need more than a moderately sized combo. It's unfortunate that everyone is into such loud music nowadays... there's a gig in my area for a maximum of 25 people ( usually 50+ :meh: ) that has a Marshall stack, Ampeg stack, and an extremely loud drum set... yet somehow everything has to be mic'ed and amplified to the point where the kick drum can knock you over if you're under 200lbs. :bag: