6AC7 Amplifier (T450E)

Obtained in MIT documentation, this 4-stage circuit has high gain for small signals. The power supply sources 150 V.

4-Band Rectangular Generator (CB25327E)
This circuit generates signals in four frequency bands with the threshold values indicated in...
Dark switch (CB8256E)
This twilight switch or pass switch was obtained from a 1967 Philips documentation. The circuit...
Noise Generator (CB7078E)
Published in Popular Electronics with the curious name of Obnoxious Noisemaker, this 1968 circuit...