That speaker seems a bit on the low side of efficiency (93dB) for an amp of only 7-10 watts! Nice speaker though. I'd be putting at least 10x more power on that unless the speaker was in a small room.
This is what I know about the Tenor (we had a few in here for service some years back): It is a differential design but using a circuit similar to what is in the BAT VK-60, which is to say two cascaded gain stages driving the output section. That is how our very early amps worked but back in the early 1980s I realized that there were too many problems with the approach (in particular DC Offsets which would result in unequal drive to whatever stage was succeeding, resulting in distortion, especially the 2nd harmonic).
The 2nd harmonic suggests a quadratic non-linearity is present. The differential design suggests a cubic will be present also. Further that amp employs feedback (although not nearly as much as is needed) while the WAVAC does not. I would expect the Tenor to be fast and transparent but a bit dry, perhaps a bit bright and less engaging compared to the SET. Do I have this right?
