Looks like it may be a 6U8 or 12BY7. Yep, 6AQ5s and 5763s. 73 – Mike

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

908-902-3831

From: [email protected] <[email protected]> On Behalf Of [email protected]
Sent: Saturday, June 22, 2024 8:59 AM
To: B. Smith <[email protected]>; Milsurplus <[email protected]>
Subject: Re: [Milsurplus] Mystery Circuit

A conversion of a type 42 amplifier into an 80 meter MOPA. The question is what type of miniature tube? 

I used to build 6AQ5 MOPA's in my pre-solid state QRP days.

Mike N2MS