Circuit Diagram Knowledge

Many modern high quality amplifiers have loudness controls built in. In most instances they are manually switched into circuit when required  in a few amplifiers the circuit is switched in at all times.
Nevertheless there are innumerable older or present-day low-priced amplifiers that are not fitted with loudness compensation - and it is for units such as these that this simple project has been designed. The device shown is for a mono amplifier two are required for stereo amplifiers. lt can be very simply assembled on tag strips or matrix board, and, when completed connected between your preamplifier and main amplifier. lf yours is an integrated unit it should be readily possible to break into the volume control circuit just connect the unit in series with the slider terminal of the potentiometer. Screened leads may be necessary of long lengths are required.  We would like to emphasize that this is a c0mpr0mise circuit. Ideally a loudness control must be designed specifically to suit the amplifier for which it is intended. Also the degree of Loudness compensation should be related to the volume control setting. This latter requirement involves replacing the existing volume control by a suitably tapped potentiometer a device that is not readily available  "off the shelf" - so the circuit shown here introduces a fixed amount or compensation that is adequate for moderate listening levels. This circuit will suit most amplifiers quite well ·- and in any case can be adjusted by minor variation of component values if required. `Switch SW1 should be a double·p0le double-throw type if stereo operation is required.