The RU-EQ3 from RDL is a three band, shelving single channel EQ and features a balanced bridging input, which may be connected unbalanced if desired. The output driver is 150 Ω balanced, and is intended to drive unbalanced or balanced lines of 150 Ω or higher impedance.
The three front-panel knobs provide active equalization, each controlling a separate audio band. The bands were carefully selected to yield a module that works effectively in a wide variety of systems with each band's center frequency being either boosted or attenuated by up to12dB.
The bandwidths of the low and high bands were selected so that those controls can be functionally considered as bass and treble controls. A third midrange control is optimized to voice band adjustment, with the overlap tailored to provide smooth operation for wideband music applications.
A feature unique to the RU-EQ series is the OVERLOAD indicating LED. When audio signals are equalized, the boosted level can cause the output circuit to clip. The OVERLOAD indicator flashes if either the input or output stage clips.