Low noise amplifier (T466E)

Found in 1948 MIT documentation, this 4-tube amplifier is characterized by its low noise level.

Operational VCO (CB13131E)
The circuit shown in the figure uses two of the four operational amplifiers found on the LM324...
Integrated Tone Control (CB14793E)
We found this circuit in a publication from the 1980s. The circuit can still be easily implemented...
Light Relay (CB473)
In this circuit the relay triggers on when light falls onto the sensor, a common LDR. Power supply...