10-20-2020, 08:25 PM
Beedoola,
Definitely check the screen resistors, they need to be 1k 5W. The 6550s sound great in the V4, but consider moving on to a KT-88 when these crap out. I have found that the KT-88s take the high screen voltage better.
I've heard of people swapping the preamp tubes, I don't think it will get you very much, as the power amp will distort well before the preamp in the V4.
When you say you want more headroom, what exactly are you looking for?
-Hangman
Definitely check the screen resistors, they need to be 1k 5W. The 6550s sound great in the V4, but consider moving on to a KT-88 when these crap out. I have found that the KT-88s take the high screen voltage better.
I've heard of people swapping the preamp tubes, I don't think it will get you very much, as the power amp will distort well before the preamp in the V4.
When you say you want more headroom, what exactly are you looking for?
-Hangman