303· Verstärker

The QUAD 303 is a stereo power amplifier that revives the 1960s original with a modern internal design. It keeps the symmetrical 'triples' output arrangement, which holds resting current independent of output transistor temperature and keeps the output devices within their ratings. Unlike the earlier quasi-complementary circuit, this version uses a fully complementary output stage, aimed at better linearity and stability with high voltage and current.

Rated output is 2 x 50W into 8 ohms and 70W into 4 ohms, with up to 10A of current into difficult loads, so it can drive a wide range of speakers including QUAD's electrostatic models. A stereo/bridge selector allows mono-block use at 140W into 8 ohms or 170W into 4 ohms. A custom 200VA toroidal transformer supplies the amplifier.

Inputs are one single-ended RCA line input and one balanced XLR input. Outputs are a stereo speaker terminal pair with binding posts, plus a 12V trigger input and a linked 12V trigger output. The anodised chassis has CNC-routed side heat sinks and a finish called Classic QUAD Grey. It is the matching partner to the QUAD 33 preamplifier.