Sure. But that's how they -say- it works....switches the 12ax7 and ef86 in and out of the front end and the 12ax7 cant seem to get the chimey highs the ef86 has.
But is it really -only- switching between those tubes and doing nothing else to process sound? Because I doubt it...
Always reminds me of one of those "hybrid" amps. It's tube channel had the 12AX7 triode configured as cathode follower so the tube in that channel did practically nothing short from little signal attenuation. What was not mentioned in marketing bulletins was that the tube channel also featured a fixed band-pass + mid-scoop EQ and clipping diodes. The "tube sound" of those was naturally very audible and easy to distinct.
Well, they certainly ain't going to sound drastically different -as is- if running clean. Which is why the traditional pentode to V1 is kinda senseless arrangement because chance is you never overdrive that stage to begin with.I bet that if you get two gain stages, a triode and a pentode one, both driving a volume pot, set to the same output level and switch back and forth, you can't tell one from the other.
Overdriven pentode and triode will clip somewhat differently though; a triode will slightly "gain compress" on one half wave before hard clipping while a pentode will usually just hard clip unless you "force" gain compression via screen. How audiblr is THAT difference. Not very. In general both still sound like clipping distortion.
And because circuit naturally has paramount importance plain generalisations about triodes and pentode operation don't even take very far...
Oh, but one can configure pentode to triode very easily, and even blend between the two states so it shouldn't be too difficult to devise schemes for evaluating triode vs. pentode, everything else staying the same. Those two modes will, however, have drastic gain difference, which you need to compensate.