It's a 5A3 - gets a little flabby maxed with Humbuckers but sweet with single coils.
Some guy was trading this 75 SFDR in at the local Guitar Sinner and I happened to be there.
It was not working and I don't know what they gave him for it, but I got it as is for [a very low price]
It had all original parts, including the RCA tubes when I got it home, but one power tube was dead.
Also the reverb send tube socket was corroded really bad.
New filter caps and a new pair of power tubes and it runs great.
Was going to BF it, but the circuit was identical except for the rectifier.
I put the original speaker away for safe keeping and threw a Weber 12F-150T in it. Love it.