New member. Interested in Dynaco ST400 and ST416 info.

I'll mostly be lurking but I've got several ST400s and a ST416 I've been maintaining for a few decades and looking around to see what people are doing to make them a little nicer. My ST416 is about to get a new PC30 and filter caps from AkiTika and fresh PC28s from Fantasia since both boards are pretty cooked after 5 decades esp under the PC28 resistors that I did the 3watt metal film replacement on a few years ago and spaced them off the board but the pcboards were already pretty crispy...
 
I do get annoyed with these amps. Sometimes they act up and I just get unhappy and toss them in a corner and then acquire and use something else for a while. This is usually because I didn't do something I should have done properly the first time. This works except that all these amps are heavy and I'm at risk of forming a gravity well and subsequent singularity.