Ralph (Atmasphere), Class A, AB, etc aside, I think it's also worth mentioning that many tube amps use negative feedback which reduces the output impedance at the taps. I would surmise that if a tube amp's output impedance off the 8 ohm tap is 1 ohm, and say half that off the 4 ohm tap, the tube amp may behave somewhat "SS-like" in the way it drives speakers that were voiced to be driven by a SS amp.
For example, I understand that the output regulation of my amp is approx. 1.2 db off the 8 ohm tap, which I think permits the inference that my amp can drive a speaker with a varying impedance plot so that the speaker's output SPL as a function of FR is pretty flat. Perhaps even better performance off the 4 ohm tap. Of course, there's the issues you have written so much about: odd ordered harmonic distortion and TIM distortion.
I think this post summarizes the numerous on-line and off-line conversation I have had with you and Al.
Regards,
Bruce
For example, I understand that the output regulation of my amp is approx. 1.2 db off the 8 ohm tap, which I think permits the inference that my amp can drive a speaker with a varying impedance plot so that the speaker's output SPL as a function of FR is pretty flat. Perhaps even better performance off the 4 ohm tap. Of course, there's the issues you have written so much about: odd ordered harmonic distortion and TIM distortion.
I think this post summarizes the numerous on-line and off-line conversation I have had with you and Al.
Regards,
Bruce