Crystal oscillator with a 6A6 (T437E)

We found this circuit with the 6A6 double triode in a 1938 Radio Handbook. The power source is not provided.

FET Input Operational Stage (CB14620E)
The presented circuit was found in the National Semiconductor FET Databook. The setting applies to other...
Amplifier for 12 V (CB8962E)
This configuration with the LM383 appears elsewhere on this site. The circuit shown was obtained...
High Impedance Preamplifier (CB941E)
This very high input impedance preamplifier is from a publication of 1977 but can also be mounted...