Hi all, wondering if anyone can shed some light on this predicament. I have a 62 Pro that has been my main gigging amp for 15 years (Pedal Steel.) With a JBL D-130F, this has been a magical amp, full, bright, warm, clean. . But I had an elusive short that dogged me forever, causing crackling and pops at inopportune times. Over the years I have basically had the thing rebuilt chasing this down, and finally I think I got it licked by replacing a tube socket. At the same time, the tech who did the work recommended replacing some caps that had strayed from spec, putting in a fresh set of preamp tubes, and replacing some more caps in the tremolo section to try to get rid of a thump it had developed at higher intensity settings After I got it back the amp sounds great in some regards (quieter for sure) but there has been a drastic tonal change. It lost a lot of presence/high end, seems to be on both channels. Dialing the Treble knob up brings it back but it's a thinner brightness than before, not as "open", chimey, glassy, Fendery as before. The Normal channel is muted, and the Vibrato channel is choked & nasally. In addition, the Presence knob has lost a lot of its effect, it does add in some crispy top end but to my ear a much narrower band of it. So, we've started going backwards, restoring some of the original parts, putting the old tubes back in. . . mostly this has just brought back the noise from before, nothing has restored the previous tonal character of the amp. At this point, the only thing left to roll back is the tremolo circuit, there are about 5 caps in there that he replaced with poly film types, and one big gumdrop on the intensity knob (which was changed to reign in the range of the trem sweep which he thought was causing the thump when it bottomed out. . .) My question, before I take it back one more time and make the poor guy undo another batch of his work - is it possible that these components in the trem section would have an overall affect on the tone of the amp? Or is there something else that we should be looking at that would do this? The tube socket?? Of course the power tubes, speaker, output tranny. . . but none of those were messed with (unless there was some secondary impact from the other changes. . .) I know that it's not always possible to go backwards with these things, and it may have just sounded a certain way with the parts that were in it. . . but I want to make sure we don't go on a wild goose chase when maybe one of the steps that we took had an unforseen effect that could be undone. Also, with all the other work that has been done on this amp (not that many components in there are original, really) it has always retained its basic character. Something this time made a pretty drastic difference. Thanks!!! BTW the tech is being very accommodating about helping me sort this out, and he's done great work for me on other amps. I think we're both going to learn something from this!