Originally Posted by nosuch
Got the woody jr. yesterday and it looks stunning (my wife says it looks like a cool box actually) and sounds as I remember my pro jr. (You have to turn it up a bit to make it sound good). There is some tube rattling so I might change tubes. Must I rebias the amp or just put in a matched pair of 84s?
I don't think you need to rebias when swapping EL84s in a Pro Jr. By the way, the awful spring tube retainers (a horrible design) are often the cause of rattling and other undesirable noise in the PJ. Usually, you can just remove them as long as your tubes fit fairly snugly in the sockets. PJs are super tube-sensitive. I've done extensive swapping in mine and was surprised to find that JJ EL84s (and the new "Mullard" "reissues") proved to be by far the quietest and best-sounding options -- more so than numerous pricey NOS tubes I tried. My own PJ is one of the first made (USA) and I love it but have found that it took a fair amount of fussing to conquer excessive noise. Quiet tubes definitely helped. (And the reverse... put a microphonic tube in a PJ, and run for your life!) Good luck. These amps are worth the fun/fussing to dial them in.