Low noise amplifier (T466E)

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

Body Heat Detector (CB25684E)
Using a piezoelectric sensor of the time, this circuit was found in the February 1994 issue of...
12 To 9 V Converter with Protection (CB5006E)
I found this circuit in an old English magazine from 1981, but it can still be assembled with some...
1 KHz Band-Pass Filter (CB242E)
Only signals about 1 kHz can pass through this tuned circuit. The main component is a operational...