I'm unsure of the age of my Classic 30 that I got on a trade two years ago. Made in USA, black, square style. There is a 2005 in the serial number sticker, not sure if that's what it is...probably? Its been a pretty good amp but a couple months ago it developed a pretty loud crackling which, would get louder when I would move the power tubes in 4 & 5. The power tubes are still Groove tubes that were in the amp. I had a new set of JJs to swap in but symptom remained. I figured the Classic 30 could use a cap job and also resoldering the tube sockets could go a long way towards helping the problem I have a buddy that is an electrical engineer and has done some amp work on a Music Man for me in the past. Although there's warnings and trepidation on the Internet about working on C30s ...in two hours I was walking out of his house with a great result. I came to his house with prepped with that second set of JJ EL84s and seven new capacitors: (2) 47uF 500V by F&T (3) 22uF 500V by F&T from Amplified Parts.com (2) 2200uF 50V by Nichicon from Radio Shack online He swapped out all seven capacitors, touched up all solder points on the tube sockets, and cleaned the pots. Re-installed the tubes, we stayed with the Groove tubes. Also, I use 12Ax7s, old RCA's in V1 & V3 and in V2 is an EHX. It seems like the tube brand in V2 doesn't matter a whole lot We didn't test along the way whether it was the caps or a tube socket soldering. The sockets didn't appear loose although he though a few were suspect/lean on solder. None of the caps were leaking and he thought his multimeter would be inadequate to test the old capacitors. FWIW, he not to fully unfold the 3 circuit boards. They were flexed apart a little bit to create some room to work. The result is that the amp sounds SO much better. No noise & sounds great, ready for a new year of gigs.