The 12B4 version is just a second socket away. Minor re-fits to the heater supply unless a voltage regulator was used, then it is just a matter of the second socket.

Anyway, in case you noticed, the first thing I wanted to do is hotrod the circuit...
cheers,
Douglas

I feel that I can get equal or superior sound from a cascoded MOSFET mu-follower 76 (CMMF76)linestage

Now I have not tried the 76, but I have heard the rest of his system, and introduced him to gas tube regulated/MOSFET mu follower linestages.

Anyway, looking arond is absolutely not a Sin.
cheers,
Douglas

Very linear, cool looking (vintage ST-shape), µ=13,8 - but low current tube... And 5-pin sockets can be found (new Chinese ceramic and old amphenol).
L-Ken-Rad `55, R-Radiofotos `39.

• 76.pdf

Given the number of generations Doug is ahead of us, I think you're son will be finishing it up for you.

I would like to revisit Guinevere. The build quality of mine is OK, but I think I can do a lot more given some time. Also, I would like to integrate dual 12b4s.......Colin

By the time all that is done, it looks pretty messy, but I have lost interest in doing it pretty, and would rather spend effort and resources on a new project( v. building a fisished and presentation-worthy job of it ). I don't see much reason to emend this practice either.
Cheers,
Douglas

I would like to go back and beef up the chassis some. Right now it's sitting on a piece of copper that's not the best platform. When doing this I would like to add the 2nd rectifier (and get it running again.)......Colin

I don't know. These are the most incredibly microphonic tubes i have ever seen/heard.

I have 2 sets none are remotly usable...John