Karaoke Forums

In one of the threads posted by Jian, I read where the power of the amplifier can be limited by the size of the electrical circuit.    Here we go....  This is going to get real interesting.  

It says a 15 amp circuit delivers 1800 watts of electricity.   So a 2000 watt amplifier will only be able to put out 1800 watts, because that's all the circuit can deliver.

Now I always thought that an "amplifier" amplified the amount of power.   What are the copper windings doing in the amplifier if not boosting the power?

So if you use two 2000 watt amplifiers (or bi-amp,) then you will need to plug them into seperate circuits or you will still be limited to the 1800 watt figure.   Minus all the wattage that the rest of your equipment uses.    So you won't even get the full 1800 watts.  And if the bar circuit has other things running off of that circuit then the number gets even smaller.   So you still, no matter what will never get 4000 watts of power, even with two 2000 watt amps.

So now..... we need someone that really knows what they are talking about to straighten all of this out for us to digest in an uncomplicated manner.  

I don't want to hear a lot of I think this and I think that...... If you don't know anything for a fact, ....STAY OUT.......don't guess.  

Yes....I know I posted on the wrong forum... Oppps    :whistle:    Hey, It's karaoke, not brain surgery....

feel free to correct me if I'm wrong, but at 110 volts, 15 amps will result in 1650 watts.....at 220 volts, 15 amps will result in 3300 watts......many factors contribute to the final output of your amp.....I'm no expert......just my 2 cents

Want the bottom line:  Get the manufactures specs.  Read on if you want more

First, when you are saying 2000 watt amp, what does that mean.  For instance:
Power Output (1 kHz)
              Stereo Bridge                  Mono
             8 Ohm   4 Ohm    2 Ohm    8 Ohm   4 Ohm
XTi 4000  650W    1200W    1600W*  2400W   3200W*
XTi 2000  475W    800W      1000W*  1600W  2000W*
XTi 1000  275W    500W       700W*   1000W  1400W*
*With 1% THD.

The XTI 2000 is considered a 2000w amp

AC Line Current:

XTi 1000: 6.5A
XTi 2000: 6.9A
XTi 4000: 8.0A

So 6.9a is well below 15a circuit, However.......

This is based on typcial programming material.  If you start overdriving the amp and clip the sound, the Amp draw could jump up into the 11-13a range.  However....

If also depends on your speaker impeadence.  

Check out this link.  It provides a good chart on powerloading of a different amp, a CE2000.  http://www.crownaudio.com/pdf/amps/138367.pdf

Whatever you do, keep it under, as "brownout" will occur (line voltage dropping) due to drawing more that 15a in very short bursts for peak music notes.  This is damaging for your amp.

for those of us who don't understand electricity (i'm still fascinated that there's a little man in my ice box who turns the light on and off for me), that's about a clear as the mississippi!  but i do applaud your knowledge and the effort to help us laymen out!

_________________
All work and no play make Homer something something

This is really interesting - I'm way over my head here, but if your equipment was trying to pull
to much electricity wouldn't it blow the circuit? I always asked the owner which plug ins to use because if I did blow a fuse at least I asked.

_________________
[shadow=pink][glow=deepskyblue]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[updown]~*~ MONKEY BUSINESS KARAOKE~*~ [/shadow][/updown][/glow]

The 1800 watt figure came out of the thread, not me.

And how about allowing for oscillation?.......for your amp, and your speakers

Typically, speakers will have two ratings for power: RMS and Peak. The RMS is the typical aveage power consumption and the Peak is the how high the power spike it would take. Usually an amp would provide fairly steady power but with power spikes and such, it could drive the amperage to speakers higher. Remember, it's not the voltage but amperage that kills speakers. If you connect your amp to a reliable power source, such as surge protected power strip, your chances of peaking out should be minimum.

_________________

Seize the day and SING!!!

Thank you, Eben.....how are you doing, buddy?......having any luck finding that certain someone....she's out there somewhere......but there is an element of luck involved.........oscillation can also cause your amp to overheat, if I'm not mistaken.......if you have a 500 watt amp at 4 ohms......would you run it at more than 250 watts continuously?.......take care......johnny

As quoted in first sentence:  Look at the manufactures specs.

Ice box man example:
The door opens, the light goes on.  The door closes the light goes off (how can you be really sure - )

Amp example:
The music goes in, you draw 6.9a against a 15a circuit

The reason the other information was provided was for this scenario:
You buy a Biggg ol Truck - It uses 6.9 gallons of gas per hour
If you drive your Big Truck with "pedal to the metal" (Amp Clipping/overdriving) you use lots more fuel, say like 11-13 gallons an hour, and you Big truck tends to explode.
If you modify the engine to get more power (using 2 or 4 ohm speaker set up) you use more fuel, the the engine (amp) has been designed for that, so no problems

Hope this helps, though I still not really sure if the light in the ice box does ACTUALLY go off.

Most circuit breakers are designed to "Blow" when a CONTINOUS overload (using too much electricity) situation exists.

Brownouts are a condition where you are drawing too much electricity for a very short duration (say a bass note), and since the circuit breaker DOESN'T "Blow", a temporary reduction of voltage occurrs.  This is very bad for your amps.

You can kind of sort of relate a brownout condition to a mis-fire on your car.  If you are drving the car hard and it starts mis-firing every couple of seconds.  Your car will not shut off, but it is very bad for the engine.

That's why its a good idea to have a power conditioner for your equipment to protect your investment.

The question remains unanswered.    :whistle:    Ossilation doesn't matter, ohms doesn't matter, gas mileage doesn't matter, nothing matters in this question, but the following.    The 1800 watts and 2000 watts are arbitrary figures.   It doesn't matter what they are or if I have speakers hooked up surrounding Cleveland..  

If the amp can put out "X" amount of watts at full power and the circuit puts out less total watts than the amp, what happens?   Does the amp work to it's full capacity or the full capacity the circuit can deliver?   This is a very simple question, with I assume a complicated answer.

The circuit will blow a fuse at full power.

probably before full power is reached.....doesn't matter, who runs their amp full power?......no me

All this talk about watts! So I want to ask a question. Why use watts as a rating of something that makes sound? Would it not make sense to use decibels to measure sound output?  I know we all want to know how much power our equipment has but power doesn't equal sound does it? I know I might not be exactly on topic with this question but for my own curiosity I am asking.

I'm gettin 18 amps at 110v pushing 2000watts.
2kwts is the MAX it can put out, it does not run on max power even if you have everything turned all the way up. It runs at what the RMS value that is allotted for the unit. This will show on the unit itself.

I know you don't like these kind of answers and that you don't like me that much either. But, there it is...

E=I*R
W=E*R or
(I(squared)* R) = W

If it spikes to max power it will blow the fuse. It may melt the fuse at nominal power.



It could be that I should just stay out as it says in the OP.

The key peice of information that would help this formula actually work is the actual power that the unit says on the label, not the marketing department's dream sheet.

Pablo - I like how you explain things. It makes it much easier to understand.

_________________
[shadow=pink][glow=deepskyblue]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
[updown]~*~ MONKEY BUSINESS KARAOKE~*~ [/shadow][/updown][/glow]

This article may explain it better. http://www.prosoundweb.com/lsi/power/power.php

There are two parts read both. But don't blame me if you don't understand it.

_________________
I can neither confirm nor deny ever having or knowing anything about nothing.... mrscott

Primary reason is that, as you stated, decibal does not equal to power. The circuit may take maximum power it can but the decibal output can be lower mostly due to the power conversion efficiency. It depends on how well the circuit processes power, it can put out high decibal or not. You can put maximum current through the circuit and blow it before you even achieve decent decibal. So, it's all about operating your equipment to best efficiency.

Here is basic equation of power. If current=I, Resistance/Impedance=R, Voltage=V, power (in watts)=W, then:

V*I=W
V/I=R, V=IR
W=I(sqr)R

So, the way the fuse/trip circuit works is that it works on total energy. If the total energy exceeds the maximum, it will blow based on the amperage. What that means is that if you graph the amperage versus time on a graph paper, the area under the curve is what triggers the blowout. So, if you have 1000A for only a micro second, it will less likely to blow than if you have 100A for half a second. So, it's not only the total amperage (based on steady 115V for example) times the total time the circuit exceeds the amperage. The electronic circuit works the same way. It has operating power it can handle and depends on how much energy goes through the system, it can blow up or be ok.

So, if you have 1200 watt of power going through an equipment that is rated for 1500 watts, with 120 volts steady voltage, then you would be pushing 10 amps of current through that circuit. Let's say you get a spike of 5 amps. That would mean total of 5x120=600 watts of total power is generated. However, if that 5 amp was only for 1 millisecond, that means you only got 60 watts per second of power, which would probably not damage the circuit. If you got that for a second, the chance of the circuit blowing is very good since you are getting 600 watts of power for a full second.

Also, typical circuits are made so that you have at least some head room, otherwise equipment would fail all the time. So, typically + or - 10% head room is built in to the circuit. So, occasional spike of power would not damage the equipment. However, pushing it to the limit all the time would be asking for trouble.

_________________

Seize the day and SING!!!

1.  I have never posted that I didn't like anybody, so knock it off.

2.  The question is still unanswered.      How can you get 18 amps on a 15 amp circuit, unless it's a 20 amp circuit?


The answer to the original question doesn't call for formulas, fuses or calculations.    

Can an amplifier put out more watts than the circuit puts out in watts?