I have very nearly finished re-engineering a pair of Dynaco MkIV monos.
I've replaced PT for 240V mains, and used completely new schematic with 2 x 6CG7 and 2 x KT88 output tubes, with emphasis on classA1 and fidelity rather than high power.
See my new page at
http://www.turneraudio.com.au/Dynaco-mkIV-reformed.html
I have also edited an old page bout Dynaco ST70. This page did have my hand drawn schematic for what I did in 1999, and what a terrible mess that schematic was!
That schematic is still there, but a whole lot of new info is there now.
The ST70 can be taught to sing extremely well, using side cutters, hot soldering iron, and other implements of torture. It can also be taught to never smoke, by application of a minor amount of Squalid Steight devices.
See the revised page on ST70 at
http://www.turneraudio.com.au/dynacost70mods.htm
Patrick Turner.