Post by MarkSAnyway, for a pair of restored to stock Dynaco MK lll's & Vlad causing all kinds of chaos & tube inflation, what KT88's or 6550's are out there that can handle a Mk lll reliably?
At this stage of the game, and assuming you are not looking for NOS, I would start with Jj tubes. I would *AVOID* anything made in China. Matching is a good thing, and technically, you need only match within an amp, not across the two of them, although if you are willing to pay the freight, that is not a bad thing either. The issue is that small differences between the amps more-or-less reduce the benefit of cross-amp matching anyway. Note also that within a few dozen hours, the tubes will have drifted to some degree as well.
Install the new tubes. Run the amp for about 10 minutes (ideally with a shorted input). Do the bias. Repeat every 30 minutes until there are no further changes.
Note to the rest of the multitude: These are mono amps based on the 6550/KT88 output in PP, 6AN8 driver, and 5AR4 rectifier. They are nominally rated at 60WPC with a heavy tailwind. They weigh ~25 pounds, or ~11.5 kg.
About covers it.
Peter Wieck
Melrose Park, PA