Add a switch and circuit to change between ultra-linear and triode mode in a Dynavox VR 70 E II.

[Jazzmi]

Hi all....did you know how to d it? Thanks. I just buy this amplifier low cost and good quality, I think, also with the tube preamp TPR-3.
I think it will be improved with this circuit and switch, normally used in others amplifiers as Cayin.. So, thanks for your help.
By the way, my amplifier JCV AX-Z911BK is in the workshop.