Telephone start circuit (CB10154E)

This circuit activates a recorder from the signal obtained from a telephone line in the service. It is used to make automatic call recordings.

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Preamplifier for 60 kHz band (CB20234E)
This circuit uses a loop antenna to receive and amplify signals from the 60 kHz long wave band....
a FET Tone Control (CB4515E)
This circuit was obtained from a 1967 magazine. The magazine no longer exists, but the circuit can still...
Microphone preamplifier (CB7499E)
This two-transistor preamplifier was found in a 1960 Sylvania transistor manual. The output...