electromuse A10 help please

[tcac30]

Hey,

I'm new to this forum, hope I'm posting in the proper place for this question. My friend found a 1940ish Electromuse A10 amp...it has 4 tube sockets but only 3 tubes were with the amp: 5y3 , 6SL7 , and 6F6. I know the 5y3 is the rectifier, and the 6sl7 is a preamp....but is the 6f6 the power tube? What could the missing 4th tube be?

Thanks,
Tom

[Jazz P Bass]

6F6 Power Pentode

The 6F6 is a power pentode.
Maybe it is a push pull amp & one is missing.
With the amp off, capacitors drained, see if there is relationship between the two pin #3's. Push Pull will have both at B+ voltage.
Or check pin #8 on both & see if they are grounded.

[tcac30]

you were correct

Yep....it's push-pull. We recapped the amp and put in 2 6v6s (same pinout, differnt current handling) and the amp works and sounds good. he's got an old lap steel guitar and this will be more of a display in his house than actually playing it.

Thanks for your help!
Tom