D-Lab
Silver Supporting Member
- Messages
- 17
Hello all,
I went to a Ham radio swap meet today and picked up a rough Alamo model 12 combo amp. The back is missing. Original speaker missing. Cabinet is rough, missing veneer. Missing tubes. Filter cap blasted.
Put it on the bench. Replaced the tubes/speaker/output transformer and installed new filter cap. Plays now and sounds good, however lacks gain due to the stock 6SJ7 tube. So, the question is, do I update the preamp with a 6SL7, to obtain the gain, or do I leave it stock, so not to offend the collectors? The amp is far from stock now with my repairs. I plan to make a new rear panel. The original was nothing more than 1/2 plywood. Oh yes, I also found that this amp was not wired correct as per the Riders schematic. Screen was circuit mis-wired, although I saw no evidence that the amp had past maintenance? I plan to make a schematic, in case you guys need it.
Heres a few pics of the project.
TD
I went to a Ham radio swap meet today and picked up a rough Alamo model 12 combo amp. The back is missing. Original speaker missing. Cabinet is rough, missing veneer. Missing tubes. Filter cap blasted.
Put it on the bench. Replaced the tubes/speaker/output transformer and installed new filter cap. Plays now and sounds good, however lacks gain due to the stock 6SJ7 tube. So, the question is, do I update the preamp with a 6SL7, to obtain the gain, or do I leave it stock, so not to offend the collectors? The amp is far from stock now with my repairs. I plan to make a new rear panel. The original was nothing more than 1/2 plywood. Oh yes, I also found that this amp was not wired correct as per the Riders schematic. Screen was circuit mis-wired, although I saw no evidence that the amp had past maintenance? I plan to make a schematic, in case you guys need it.
Heres a few pics of the project.
TD
