The operational amplifier for this tone control found in a 1977 Signetics manual may be the 741. The power supply must be symmetrical and the signal cables short. The bass gain is 20 dB.
With a load of 35 ohms this amplifier provides a power of a few tens of milliwatts, but we can use an...
This 1965 General Electric circuit uses a "Thyrector" that is a suppressor of the time. The...
The coil of this transmitter has 4 coils of wire 26 or 28 in the form of 1 cm without core and on it...