At the left in the picture below is a Hartley Oscillator using a single 45 triode.
To the right of the Hartley is a twin 45 linear amplifier.
Rear view of above:
Rear view of twin 45 linear amplifier:
Front view of twin 45 linear amplifier:
Front view of single 45 Hartley oscillator
Rear view of single 45 Hartley oscillator
