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.
This circuit is from an American publication about old neon lamps. The circuit is leak proof and...
Another useful audio circuit using an operational amplifier is the one shown in the figure. It is a...
This circuit is from a 1979 publication. The sensor consists of plates or screens that, when...