This 45 to 90 Hz hum elimination circuit was obtained from a 1980s documentation. The operational can be of any kind, including the modern low voltage ones. Power supply must be symmetrical.
![](/images/stories/cir/224712472023_144547_0001.gif)
This 45 to 90 Hz hum elimination circuit was obtained from a 1980s documentation. The operational can be of any kind, including the modern low voltage ones. Power supply must be symmetrical.