[quote name='Conan' timestamp='1461683551' post='3036722']
I don't think amps have outputs with different impedances, do they?
My understanding is that the output from the amp is in Volts, and that depending on the impedance presented by the speaker cab, that voltage creates a certain amount of movement in the speaker that we perceive as sound. More voltage = more sound.
The socket on the back of the amp indicates the minimum (or even recommended) impedance of any cab connected to it...
I believe all of the above to be true. That doesn't mean that it is, of course!
[/quote]
Mr MooseBlaster's amps are all valve though so have different transformer tappings for 8, 4 and (in the case of the CTM100) 2 ohms.
Valve amps are different from solid state - going too low on the impedance is *generally* not quite as bad because of the way the current and voltage is delivered and soaked up. With solid state amps the lower the impedance the more current the output transistors try to pass. It gets to a point where they can't keep passing more current so they eventually go pop.