well i have a amp that i suspect has a power rating of 1200 rms at 1 ohm at 18 volts not 14 volts is there any way to check this? Can i go somewhere and get it checked i know there has to be somwhere that tests power rating? its the Power Acoustik BAMF 2000/1d im sure its at 18 volts but i just want to see. it would be interesting to find out the real power output
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With a multimeter and ampprobe, you can find out the real numbers it's doing.
Another hint, your amp has 2 x 40 amp fuses. Take 80 (the total of the fuses) and multiply that by 14.4 and that gives you 1152 watts rms. Now that's saying you're at 14.4 all the time, and 100 percent efficient amp, you'd be hitting that. Your amp isn't 18 volt.
Almost every single amp is rated at 14.4 volts. Some are rated at 12 volts, some have a 14.4 and a 16 volt rating.
ok well what is a amp probe? is it just a probe that tests for amps? my buddy has all this stuff so how do i do it? is there a special track i would have to play while doing it like how you set your gain?
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that doesnt really help me without any explanation of what it is or what to do with it?^^^
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you clamp it around your
+ speaker wire. Dont put both + and - in the clamp.
P = I x V
power in watts = current in amps x voltage in volts
You can't measure power real power using this method unless your circuit is purely resistive. Any readings you get will be higher than the actual because the circuit has an inductive component. You're actually reading the apparent power coming from the amplifier of which the reactive component does no real work and is returned to the amplifier. It tends to cause heating of the amp and circuitry but does nothing to actually move the speakers.
Quote:
Real, reactive, and apparent power
The apparent power is the vector sum of real and reactive power
Engineers use the following terms to describe energy flow in a system (and assign each of them a different unit to differentiate between them):
* Real power (P) - unit: watt (W)
* Reactive power (Q) - unit: volt-amperes reactive (VAr)
* Complex power (S) - unit: volt-ampere (VA)
* Apparent Power (|S|) , that is, the absolute value of complex power S - unit: volt-ampere (VA)
In the diagram, P is the real power, Q is the reactive power (in this case positive), S is the complex power and the length of S is the apparent power.
The unit for all forms of power is the watt (symbol: W), but this unit is generally reserved for the real power component. Apparent power is conventionally expressed in volt-amperes (VA) since it is the product of rms voltage and rms current. The unit for reactive power is expressed as "var", which stands for volt-amperes reactive. Since reactive power flow transfers no net energy to the load, it is sometimes called "wattless" power.
Understanding the relationship between these three quantities lies at the heart of understanding power engineering. The mathematical relationship among them can be represented by vectors or expressed using complex numbers,
S = P + jQ \,\! (where j is the imaginary unit).
The complex value S is referred to as the complex power.
Consider a simple alternating current (AC) circuit consisting of a source and a load, where both the current and voltage are sinusoidal. If the load is purely resistive, the two quantities reverse their polarity at the same time, the direction of energy flow does not reverse, and only real power flows. If the load is purely reactive, then the voltage and current are 90 degrees out of phase and there is no net power flow. This energy flowing backwards and forwards is known as reactive power. A practical load will have resistive, inductive, and capacitive parts, and so both real and reactive power will flow to the load.
If a capacitor and an inductor are placed in parallel, then the currents flowing through the inductor and the capacitor tend to cancel out rather than adding. Conventionally, capacitors are considered to generate reactive power and inductors to consume it. This is the fundamental mechanism for controlling the power factor in electric power transmission; capacitors (or inductors) are inserted in a circuit to partially cancel reactive power of the load.
The apparent power is the product of voltage and current. Apparent power is handy for sizing of equipment or wiring. However, adding the apparent power for two loads will not accurately give the total apparent power unless they have the same displacement between current and voltage (the same power factor).
I usually do amp probe around the power wire going in to the amp while the amp is playing to see what kind of current draw is on the system. Take that, multiply that by voltage and it'll give you power. It's nice to play a test tone for a few seconds to see if voltages will stabilize. Then from there, you multiply by the efficiency of the amp and you'll have your rating. No single amp is 100% efficient.
Lanman31337 - Cavfire wrote:I usually do amp probe around the power wire going in to the amp while the amp is playing to see what kind of current draw is on the system. Take that, multiply that by voltage and it'll give you power. It's nice to play a test tone for a few seconds to see if voltages will stabilize. Then from there, you multiply by the efficiency of the amp and you'll have your rating. No single amp is 100% efficient.
That's a much better way, but I didn't know that manufacturers put out the efficiency numbers on the amps.
What's funny is that you're amplifier will put an AC component back onto the DC signal coming from the battery because of the capacitors in the amp. We get into trouble with the power companies because they transmit to us a 60Hz signal and we add a 12KHz signal back onto the line with our variable frequency drives. We've had to add huge filter banks to minimize the effect we have on the power grid. We affect the power factor on the system so much that they throw hissy fits when we take our plant down without letting them know ahead of time. (they don't bitch too much considering we pay 5 to 6 million a month for our electricity usage).
Some companies do efficiency ratings, some don't. Class a/b amps aren't efficient, around 65%. Class D are around 85-95 percent efficient. Another cool tidbit of info is class a/b amps have a sloped oval wave, while class D have a square wave (PWM)
All of our drives are PWM. I didn't know that about class D amps.
I did a 31hz test tone and got 503 watts rms. My buddy then wanted to see what his alpine 500 mono did and at 31 hz it did 279, and also we tried a 45 hz tone and it did 405 watts. Does that mean if I do a higher test tone it will give me higher numbers?
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Try using a 60 hertz test tone.
