This circuit was found in a1980s Motorola documentation. The integrated circuit is from that time. The frequency depends on the crystal.
This circuit obtains phase-inverted signals from a single signal. The circuit uses two LM741...
This circuit with the HA2400 was found in the March 1980 Radio Electronics magazine. The circuit has...
This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response...