Wasn't planning on posting the build but it might be useful to someone somewhere.
Based on the 2203 pre-amp, the output section is a bit different, but it can run el34's and in my opinion sound better. (for some reason the 6v6gt's are a lot brighter compared to the el34's, could also be the different tap you need to run the el34's and the change to the NVB)
I liked the gain mod adding a bypass cap on V2 cathode resistor (switchable) (the standard 0.68uf on the 820ohm) I liked a 10uf bypass cap added to (switchable) (mine is v1a I think ) that friedman adds to his v1b. A 270pf snubber cap across v1 pin 1 and 3 to prevent high freq oscillation. Added a switch rather than 2 input jacks to switch channels and added switchable bright caps (1nd, 4n7) and no brightcap.
NVB running off of the 8ohm tap, running a 4ohm 412 cab. elevated heaters....think thats most of the mods oh and a 220k plate load resistor for more compression rather than the stock 100k.
Total cost was about R11 000 and custom transformers can be wound at Pieter Souris Transformers, they do output transformers, chokes etc.
Schematics or layouts thats usefull:
Some build pics
