I'm in the middle of building a TMB based (largely) on the Ceriatone design / schematics. I'd been regularly visiting the site and noticed the modifications to the design.

I wrote to Nik and got the following answer:

Question: "I have checked the two layouts and the differences are that the later version has a 47n 630v cap and 100k 3W resistor across it's terminals, and secondly the EZ81 has a 10n 3kV(!) and two 1N4007 diodes across lugs 1 and 7.

Nik's answer: "As for the cap and resistor on stdby, it's just anti pop, and switch
saver (DC protection).
As for the cap and diodes, that's again protection for the tube rectifier when you use the stdby. But not need to do these - tube rectifier that usually fails with usage of
stdby switch is the GZ34, EZ81 is usually fine.
   
Same with the stdby switch mod - its optional."



Hope this helps everyone!

M