Pioneer AM/FM 4 channel stereo receiver model QX-646. 10 watts RMS into 8 ohms per channel times 4. Features one phono input, one tape monitor, low and high filters, two bass/treble controls, CD-4 separation left/right controls, loudness on/off, FM muting on/off, modes - 2ch - CD-4 - RM - SQ, functions - AM - FM mono - auto - phono - aux. Also has a tuning meter. From 1974 - 1976. Neat receiver.