The basis of this circuit is the HA2400 released at the time. The circuit is from a Radio Electronics magazine from March 1980. The power supply must be symmetrical at 15 V.
This oscillator was found in the November 1986 issue of Radio Electronics magazine. The frequency...
This sophisticated circuit with a low, medium, and high treble filter is from 1990 documentation. The...
This circuit was obtained from a 1998s Popular Electronics. The magazine no longer exists, but the...