These are my Silverface Bassmans model AB165. One is a 68, the other a 69. These amps were my main workhorse amplifiers for twenty years, until i bought my Traynor YBA-1A.
In 1980 I bought a Marshall, not quite sure but I think it was a 50 watt 2204 JMP. I was never happy with it, and I understand now that part of the reason was that it had 6550's in it, and not EL34's. It just wouldn't overdrive like I thought it should. I didn't know much about tube amps then. I had owned a Bassman some years before and was always happy with it, so when I saw two SF Bassmans in the original Dirt Cheep Music in Marietta GA in 1984, I traded the Marshall for them.
I rewired my 4x12 to be a stereo cabinet, and ran the Bassmans in stereo with a Boss stereo chorus and a Boss SD-1 overdrive. I was in tone heaven. They sure don't make 'em like this anymore. I have been running these amps pretty much dimed for all these years and the only problem I have had is a burnt power tube socket.
When I started learning about tube amps I did these modifications:
Rewire Bias Balance to Adjustable Bias.
Replaced all electrolytic caps.
Replaced bad turd brown caps with Orange Drops.
Replace phase inverter caps with .1 OD's for better low end crunch.
Remove Death Cap and replace AC cord with three wire grounded one.
Anyone who knows about Fender amps will have noticed that these amps don't look like regular Silverface Bassmans. I changed the logo and grill cloth to match my Mojo 4x10 cabinet. Don't worry, I kept the old faceplates. I had Danny cut me two new pieces of wood to attach the new cloth and logo to. They can be switched back in a few minutes.