fat_fleet
Swollen Member
My '67 Twin Reverb stopped working last night. Before the sound went out for good, it kind of swished in and out for a little while. I managed to get a recording of it:
wtf_amp
Anyhoo, after swishing in and out randomly like that for about 15 minutes, it went out completely. After it went out, I took a look at the back of the amp. Power section tubes were all still lit up normally but preamp tubes were completely dark. I went down the line swapping the preamp tubes out one-by-one with a known good one. Nothing worked, but I noticed that when I got to v6, the phase inverter, the new tube did seem to light up.. not quite as bright as one would expect from a live preamp section, but lit up nonetheless. V1-v5 remained dark and there was still no sound.
Looking at an online chart, I see that the PI should be a 12AT7.. however the tube that was in there (before the swap) was a 12AX7. Not sure if that has anything to do with my problem.
Anyways, that's about all the info I have. Thanks in advance for any ideas about this.
wtf_amp
Anyhoo, after swishing in and out randomly like that for about 15 minutes, it went out completely. After it went out, I took a look at the back of the amp. Power section tubes were all still lit up normally but preamp tubes were completely dark. I went down the line swapping the preamp tubes out one-by-one with a known good one. Nothing worked, but I noticed that when I got to v6, the phase inverter, the new tube did seem to light up.. not quite as bright as one would expect from a live preamp section, but lit up nonetheless. V1-v5 remained dark and there was still no sound.
Looking at an online chart, I see that the PI should be a 12AT7.. however the tube that was in there (before the swap) was a 12AX7. Not sure if that has anything to do with my problem.
Anyways, that's about all the info I have. Thanks in advance for any ideas about this.