Quote from: bluebooI checked the pre-amp out with the speaker disconnected, put it in my mixer and your right, the distortion's gone on both on clean and gain channel through the pre-amp out.. So does this mean anything in particular?
Yes, it means the preamp is in the clear and your fault is after the Fx point, i.e. in the power amp.
Did you try it with a known good lead between Fx Send and Fx Return?
Sorry, I should have been more specific, we are looking for the voltage across the speaker while the amp is idle, un-driven.