There is more to it than just the tube, I'm afraid. Single-ended topology has sonic advantages over push-pull topology.
What are the efficiency and impedance (minimum as well as "nominal") of your speakers? Some 845 amps are specifically designed to work well with medium efficiency speakers.
Duke
What are the efficiency and impedance (minimum as well as "nominal") of your speakers? Some 845 amps are specifically designed to work well with medium efficiency speakers.
Duke