Confused about impedance and wattage.

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Optical
Tokai
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Re: Confused about impedance and wattage.

Post by Optical »

You can understand everything about this from basic Ohms law: V = I x R and Power = V x I
Any amplifier has a fixed operating voltage, so you can see that varying the speaker impedance will therefore vary the current and therefore the power that can be achieved from that fixed operating voltage.

50W for a 4 ohms load means the operating voltage is sqrt(P X R) = sqrt(50 x 4) = 14.4V
So to change to another load, power = 14.4^2 / whatever load. For example: 14.4V^2 / 8ohms = 25.9W ; or 14.4V^2 / 16ohms = 12.9W


Tube amps are entirely different because they have output transformers which change the effective load on the amplifier.

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