I did indeed find the capacitors in the power supply very critical as well on the main board as well. Tried many different brands, my conclusion is to choose components that stay close to the original sound which is excellent IMO. Please read my old thread, but Black gates as the main filter on the main board was the best there not the replica LCR.
To get rid of that graininess some people have noted here is what i did
by passed all the switches
changed the pot for a bournes
parallel the black gate filters on the main board with Jantzen Superior (very very important to get the right overall sound) (note audio note now make black gate replicas but i feel they sound a touch more polite than the originals)
use a super regulator on the heater supply
replace every single signal cabling to western electric.
Do not change the original main cord for something fancy neither the umbilical cord, the originals will keep the original sound intact.
Use Toshibas for the pre valves, best i could find and closest to the original sound Doug wanted.
No grain, wonderful PRAT but with valve timbre kept intact and a very wide sound stage.
To get rid of that graininess some people have noted here is what i did
by passed all the switches
changed the pot for a bournes
parallel the black gate filters on the main board with Jantzen Superior (very very important to get the right overall sound) (note audio note now make black gate replicas but i feel they sound a touch more polite than the originals)
use a super regulator on the heater supply
replace every single signal cabling to western electric.
Do not change the original main cord for something fancy neither the umbilical cord, the originals will keep the original sound intact.
Use Toshibas for the pre valves, best i could find and closest to the original sound Doug wanted.
No grain, wonderful PRAT but with valve timbre kept intact and a very wide sound stage.