Marantz AM/FM 4 channel stereo receiver model 4230. From the year 1973 to 1978. 15 watts RMS in 2 channels, and 30 watts RMS in 4 channels. Features, Dolby system meter, play cal L or R selectors, record level L or R, 400hz tone, high filter, loudness on/off, FM muting, speakers, main or remote, modes, dimension, Dolby Nr selectors, for record play and FM, headphones front and rear, and both signal and tuning meters, too many features to name. Neat quadraphonic stereo receiver!