Ampeg B-15N in good shape -- sounds great, doesn't rattle (even on the dolly), not pristine but not too ratted up for an amp that's >50 years old.

I bought it 1994. The black plastic polarity switch had already been replaced with a metal toggle. Since then I:

• Replaced the output transformer
• Replaced the ungrounded power cable with a grounded one
• Replaced the straight 4 pin XLR speaker connector with a right-angle-4-pin -- keeps the auto stand-by but you can set the amp a few inches closer to the wall
• Replaced the tattered, heavily yellowed by cigarette smoke grill cloth.

It's hard to date these things. The standby switch is on the rear of the head, which would indicate post 1968 and the control panel graphics are blue silkscreen, which would indicate pre-1972. The speaker, which looks like the CTS alnico, is actually an Eminence ceramic, produced, per the codes, in the 49th week of 1969. Eminence became the standard B-15 speaker ~1973 but, according to some sources, Ampeg occasionally sourced B-15 speakers from Eminence due to supply chain shortages throughout production. So the speaker might be original, might be a replacement. Who knows? It sounds good - starts breaking up after about 11:00 on the volume.

The rectifier is an RCA 5AR4, the 6L6s are Sylvania, and the 6SL7s are Sovtek. I can't vouch for tube health but the amp sounds solid.