73 Superbass Issues (fuses blowing)
Posted: Fri Mar 25, 2016 4:03 pm
Hi all
I have my good buddies 73 PTP Superbass here. Initially it was blowing the mains fuse. I took the amp out and retubed it with a brand new quad of JJ EL34 I have on hand. The plate voltage was 512 and I set the bias accordingly. I replaced the mains fuse when I changed the tubes as well.
Ran the amp and (he uses a hot plate ok) it's 16 ohm just like the output load
I ran it loud and then the power indicator started to "dim and load" with my guitars input ok. I'd strum and you'd see the light drop and go up. (Like a visual current indicator). The output volume was "wavering" and the HT fuse then blew. I stopped at that point.
I put the proper spec SB time delay fuses in it. I think the filters might be dried up and the bias caps as well.
I realize this could be a bad PT possibly as well
The amp is 125% original. Everything. He got it from ROYAL BRIT and it looks like it came from the original owner or from a umplayed collection. It's immaculate
Has original bias caps, all original Daly filters. The dye joints are 125%. The board was never lifted
I am thinking I should replace the bias caps and the filters...
Am I correct here in my logic?
Please advise and sorry for the dumb questions
Regards
Dan
I have my good buddies 73 PTP Superbass here. Initially it was blowing the mains fuse. I took the amp out and retubed it with a brand new quad of JJ EL34 I have on hand. The plate voltage was 512 and I set the bias accordingly. I replaced the mains fuse when I changed the tubes as well.
Ran the amp and (he uses a hot plate ok) it's 16 ohm just like the output load
I ran it loud and then the power indicator started to "dim and load" with my guitars input ok. I'd strum and you'd see the light drop and go up. (Like a visual current indicator). The output volume was "wavering" and the HT fuse then blew. I stopped at that point.
I put the proper spec SB time delay fuses in it. I think the filters might be dried up and the bias caps as well.
I realize this could be a bad PT possibly as well
The amp is 125% original. Everything. He got it from ROYAL BRIT and it looks like it came from the original owner or from a umplayed collection. It's immaculate
Has original bias caps, all original Daly filters. The dye joints are 125%. The board was never lifted
I am thinking I should replace the bias caps and the filters...
Am I correct here in my logic?
Please advise and sorry for the dumb questions
Regards
Dan