i just bought this old gibson amp from my friend for 50$ The model is Gibson Plus 50. ive done alot of looking around the internet and all i have found out is that.

it is a ss slave amp
50 watts
2x10 speakers
1966-1967
made in Kalamazoo Michigan by maestro
it was probably used for both guitar and accordion

there is a wiring diagram on the gibson website.
http://www.gibson.com/Files/schematics/Gibson%20Plus%2050.pdf

if anyone could tell me anything more about it would be awesome. heres are some pics.










thanks for any info you have