Triode versus Ultralinear/Pentode

I don't understand why an end user would re-design an amplifier that had already been researched, tested and optimized by the manufacturer.

Makes no sense whatsoever.

If one desires a triode amp, then buy a triode amp...or buy an amp that allows switching from pentode to triode. Many exist at all price points.

I'm 95% there Tvad. It's why I have doubts over the wisdom of what I am considering. I think your logic is impecable. It's not like Roger said, "great idea, I don't know why I didn't think of that." - Although I'm sure he was also interested in bringing something to market with more power than triode would have provided. The whole triode idea is driven by the fact that my speakers (Merlins) like to be driven by amps with very low damping and NFB, and triode operation theoretically permits use of less NFB (or none?), etc. But I do hear the logic behind what you are saying, and I'm leaving well enough alone and going with the amp as designed by Roger.

The best I have heard Merlins is driven by a VAC 30/30 Signature.

Liquid.

Taking up atmasphere's point and changing the question. Is it always true that the compromises envolved in making an amp adjustable between Triode and Pentode, mean they will perform worse than an amp optimised for triode or pentode only?
To answer my question and having spoken to a few tube amp designers, it is my belief, that the compromises do, inevitably, have some effect on performance.

03-09-08: David12
Taking up atmasphere's point and changing the question. Is it always true that the compromises envolved in making an amp adjustable between Triode and Pentode, mean they will perform worse than an amp optimised for triode or pentode only?

I owned a VAC Phi 110/110 that had both modes. There was no compromise in performance that I could discern from other amps I have owned that were pentode only. In fact, when run in triode with zero negative feedback, in many respects it was the best sounding amp I've ever owned.