Stock Electrical, Can I go with a large amp at high ohm load?

[Jes 42 10+ year member]

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[maylar 10+ year member]

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Since we are talking about car audio I'm going to retract my statement of saying I'm absolutely right (if I ever said that),but with:
Amp 1000 watts @ 4 ohms = 71 amps

Amp 1000 watts @ 1 ohms = 71 amps

there must be something I am missing because you can't change resistance and keep power the same without supplying a different amount of electrons per second. If you are correct then I'm missing something huge or you're talking about a different part of the system as me because well "that doesn't math" lol.

You're thinking in terms of the output side of the amp. And you'd be correct, the same power at lower impedance would be higher current and lower voltage.

Everyone else is talking about the INPUT side of the amp. From the battery. Voltage is constant, at 14V. So, for 1000 watts and 14V the input current is 71 amps. Regardless of the OUTPUT impedance.

This is where efficiency comes in. You don't get something for nothing - any amp will always draw more power from the battery than it sends to the load. An amp that's 80% efficient supplying 1000 watts will draw 1250 watts from the battery. If the efficiency of the amp is better at higher output impedances, then it'll draw less power (and less current) than with a lower impedance load.

... Phizzikz

 

[adulbrich 5,000+ posts]

Not only that, but what I said earlier about the 4 ohm at a specific wattage pulling less current than .5ohm, nobody has agreed with yet for some reason. Yes, efficiency plays a role but I'm talking about the actual laws of the universe. Even if efficiency was somehow magically the same, the lower resistance at same power would pull more current and push less voltage than the higher resistance. I will demonstrate this clearly:
Wattage = Voltage X Amperage and Resistance = Voltage / Amperage

therefore...

If Wattage remains the same, and Resistance increases, Voltage increases and Amperage decreases

Edit: need to add something...

Likewise... If Wattage remains the same, and Resistance decreases, Voltage decreases and Amperage increases

I agree that even if efficency wasn't the issue, you would pull less current at 4 ohms than .5.

Im just gonna stop posting in this thread hahahha.. I made myself look like an asshat here

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Lol, yes

 

[mlstrass 5,000+ posts]

F math....HO alts and batts work for me lol