This circuit is from an old English publication from 1968. We can implement it with TIP32 transistors in a more modern version. Power can be done with either large batteries or a power supply.
We found this circuit in a documentation from the 90s. It lets frequencies around 1 kHz pass,...
The circuit shown by the figure below can produce signals in the range between 20 kHz and 30 kHz....
This circuit is from a publication from 1980 and can be used as an amplifier to supply loads up to...