This module combines the functions of both preamplifier and volume attenuator with tone control. The latter function allows independent control of the treble, midrange and bass levels. The preamplifier stage adopts a pair of NE5532 OPA mounted on DIP8 and therefore interchangeable to adapt the sound reproduction to its listening and audio system.

The power supply stage benefits from a high quality design with signal regulation and filtering to promote accurate and precise sound reproduction. The LM317 and LM337 controllers are adjustable according to the OPA used.