In addition to tone control, this circuit of the SGS 1982 linear integrated circuit manual has a loudness control. The supply must be made with a 24V voltage source.
This circuit can generate signals up to 100 kHz. Found in documentation from the 1980s, it makes...
Some old record players use variable reluctance phono pickups, requiring a special amplifier...
This circuit is from a Radio Electronics from July 1965. The circuit uses components from the time...