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In the papers following my amplifier, it says that it is capable of 150Wpc i 8 Ohms, 230Wpc i 4 Ohms, but a mindblowing +/- 40 Amperes of peak current.

In my book this is pretty much, but knowing my amp very well (on year 4 now), I have no reason to not believe it. How much current is your amp capable of letting go, compared to the Wattage?

Damned if I know and I can't make any sense out of the Nu Force specifications on their web site http://www.nuforce.com/hi/products/Monoamp/ref9v3se/index.php
Don't care really as my ears tell me there's way more than enough power, either as current or watts, to run my Usher Be 10's. Mind you I never play music as rock concert levels and the sub bass is taken care of by the amps inside a pair of Velodyne DD15's and I'm not going hunting around for the power specs for those either.

Wow, that sure is alot of amp draw. I thought my B&K amp drew alot of current at 17 amps. It has 200wpc into 8 ohms and 375wpc into 4 ohms. The best thing I did for it was have a dedicated 20 amp circuit installed for it.

Before I had the dedicated line installed, the amp always dimmed the living room lights or blew the circuit breaker when I turned it on. It seems to draw alot of current at turn on.

Of course, it is PEAK meaning short term current. 40 amps is good. 10ms is all you need.

John verify my math:

The square root of watts/ohms = current. current X ohms = rms voltage. Peak voltage is current X ohms X 1.41?

I might be passing around misinformation.

Correct if I am wrong with great haste!

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I also guess it's not a very common thing, as my power fuse blows at 13 Amps, and it hasn't done that yet

Perhaps it's a capacitor thing?

Capacitance is expressed in farads, whatever the hell those are.

Musical Fidelity A5 Integrated

400 watts @ 4 ohms

Current peak-to-peak = 75 amps

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I also guess it's not a very common thing, as my power fuse blows at 13 Amps, and it hasn't done that yet

Perhaps it's a capacitor thing?

Capacitance is expressed in farads, whatever the hell those are.

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On a QSC amp the current line current draw on a 260 watt/ch amp at 1/3 power with pink noise (about 90 watts per channel) is 6.6 amps per their website. I don't think I would want to be in the room to listen to that.

I also found out that my B&K 200.5 amp has a spec of 75 amps peak to peak whatever that means.

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I also found out that my B&K 200.5 amp has a spec of 75 amps peak to peak whatever that means.

Current flows in two directions, back and forth through the loudspeaker. Peak to peak refers to the difference between the positive peak and the negative peak. In your case, the amplifier will supply a maximum of 37.5 amps in each direction.

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The square root of watts/ohms = current. current X ohms = rms voltage. Peak voltage is current X ohms X 1.41?

Your math is basically correct. I would only add that peak and rms need to be the same in each equation, so that:

rms current x resistance = rms voltage
peak current x resistance = peak voltage
peak voltage = rms current x resistance x 1.41 for a sinusoidal waveform

Music is rarely sinusoidal.

Much of that has to do with power supply design and cap storage. The NAD amps are a case in point, designed for large voltage swings for short periods.

I don't understand your point. Yes, the NAD amps are designed to provide high peak outputs, but the formulas above remain the same.

Yes, thanks. I tend to over-explain.

The short term peak current output is dependent on the amount of capacitance in the power supply. A large energy storage capacity in the power supply can greatly increase short term peak power.
Amplifiers that have very large energy storage reserves will continue to have an output after AC power has been removed. The more storage the longer they will produce sound.

That energy storage is what allows some amplifiers to have very high peak current output.

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The short term peak current output is dependent on the amount of capacitance in the power supply. A large energy storage capacity in the power supply can greatly increase short term peak power.
Amplifiers that have very large energy storage reserves will continue to have an output after AC power has been removed. The more storage the longer they will produce sound.

That energy storage is what allows some amplifiers to have very high peak current output.

Hi Joe. I agree with everything you said. Not to be argumentative, but I'm now wondering if some people are misunderstanding my post about the formulas. I'm not saying that peak output currents can't be higher than 1.414 times the rms value, in fact they can be many times higher. Also, the formulas refer to the actual output, not the rated rms vs. the available peak output of an amplifier.

Is there something I said that you wish to dispute? That's fine, have at it! :-)

Since I posted them I did not say they did not.

Dispute you say!
I can't argue with math. I was an Electrical Engineer before I retired. I was only trying to point out that huge storage capacity in the power suply will allow short term peak current output well beyond an amplifiers rated output.

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It may me checked if you pull the plug in the middle of playing a tune. The amp continues to play for several seconds without AC...

Pretty cool, yes?

It may be cool, but it might not be good for your speakers. After the power is disconnected the voltage on the power supply rails starts to decrease. When you begin to hear distortion, you're actually clipping the signal. We all know what clipping can do to your tweeters. I don't mean to alarm anyone, but please be careful.

Yes, an excellent point.

I didn't think you guys would pull the plug at full blast, but just because I'm paranoid doesn't mean everybody's not against me.