Hey-Hey!!!,
I am thinking that a pentode with the load line chosen to drive below the g1=0 knee would be cool. Either this or go for a load line dominated by 2nd-HD which would drive through g1=0 to the right of the knee.Perhaps a 10% E-Linear pentode driver with a pentode ahead of that stage. EF184 in two stages perhaps? Tone control between the two stages, and a little bit of E-Linear NFB around the last stage?
I thought the 12AX7 in two stages before a 6V6 was the Champ circuit.
With a pentode final, there can be a whole lot more resistance to an imperfectly filtered B+. I am thinking 6AX5 feeding an LCLC PS with 10 uF/600B Oilers and lots of inductance. 10Hy-10uF-20Hy-10uF perhaps?
Come to think if it, I have some E55L/8233 pentodes that would probably sing with ~150V and 1k5 load. I was just informed that Heyboer has some sweet SE output Iron. That would be just the ticket.
cheers,
Douglas