Greetings. I am relatively new to the tube amp world, and I have a vexing problem. My brother gave me his ten year old Jolida 302A (he claims there was only five years of wear on it). I had it for a year and it played superbly.
Last Thanksgiving it blew a power tube, which I replaced with a new EL34. It played wonderfully until News Year Eve when it blew the new tube in the same socket. I took it in to the shop, and the repairman said he replaced a bias resistors and capacitors.
The machine played superbly until two nights ago when it blew another tube, right next to the socket that blew before. The repairman seems uncertain what could be the problem, other than a transformer which he has tested, since he said he has replaced everything that could go wrong.
I am at my wits end: three blown tubes in four months. Is it possible that I have some weird power surge in my house that is blowing them out? I use a surge protector. There are other machines (cd player and turntable) connected to the same socket but these are fine. In fact, I have a tube headphone amp on the same line and that is fine as well.
I would appreciate any advice on this. Thanks!