Low noise amplifier (T466E)

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

Audible Logic Probe (CB13787E)
We found this logic level indicator in a 1976 amateur radio documentation. The circuit is powered by...
RCA Radio Model 7BT 9J (CB18442E)
This 6-transistor transistor radio is a RCA product from the 1960s. The circuit is powered by a 9...
JFET Sample and Hold (CB5955E)
The operational amplifier is old. The circuit is from an 80's documentation but can be designed...