One of the main issues I had to undertake as a Peavey Classic 50 212 (<2000) owner was the reverb not working at all after several years of use. One might think "ok, take the old tubes out, and replace them with new ones". Sure, but what are you supposed to do when there are no specs on the old tubes (just an 12AX7)? You dig!
After digging in shops, YT videos, blogs and forums, I ended up to use the "ol' faithful russian" to do the task with the phase reverse and the spring reverb "manipulation".
Great! Everything back to normal! I even experience better control on how the amp's reverb "breaks up" as I turn the knob. Great tones for rock/blues (my thing), my Strat sings like a humming bird. The tube seems to combine very nicely with the preamp and gain tubes (Tung Sol, TAD) giving my amp all the depth and bite it had when I bought it - it also feels a little bit crunchier, although I put the same power tubes as before. So, nice LPS tube for the classic series, should give it a try!