Quick quiestion on External Cabnets

[IM4Tone]

Re: Quick quiestion on External Cabnets

I'm unclear. You're saying that in a tube amp, Ohm's law doesn't hold, so a speaker system with half the impedance gets the same current and therefore the same power? That makes no sense. I agree that tubes don't act ideally (not nearly as close to the ideal transistor behavior as solid-state anyway), but unless the tubes are providing a self-limiting effect that keeps the impedance of the speaker circuit roughly constant, or the amp design only works at a single nominal impedance so adding cabs requires changing the impedance of the ones you have, more cabs equals less impedance equals more speaker circuit power.

Ohms' law ALWAYS is a law, it always 'holds.
In a solid state amp, halving the resistance will double the current, hence doubling the wattage. When you're near max for the amp (the OP was talking about very low powered amps) this doubling of current will most likely burn up the amp.
In a tube amp, halving the speaker load is accompanied by changing taps (via an impedance switch or automatically by the way a second speaker output jack is wired) which changes the turn ratio of the output transformer, which in-turn changes the reflected impedance that is seen by the tubes. Wattage may change slightly due to the specific design of the amp, but nowhere the magnitude of 2X.
The law of conservation of energy is also always a law. You cannot create energy via a passive device (speaker), only by putting out more energy from the energy source (the amp).

 

[skyydogg01]

Re: Quick quiestion on External Cabnets

Remember, too, that Sensitivity is measured at a certain frequency ... like 1 kHz ... not through the entire frequency range.