Low efficiency? Yes, I think the S-30 is going to run out of gas. There's no way to solve this other than be using a different amp or different speakers.

Agree, to solve the low impedance problem, the autoformers will do the trick. To solve the low efficiency problem, you need more watts.

Agree, to solve the low impedance problem, the autoformers will do the trick. To solve the low efficiency problem, you need more watts.