Big Marantz with 4 cool blue VU meters. All settings set right to factory specs at 230V input. Contacts cleaned. Sounds very nice. This is a add-on surround effect amplifier, your own 2-channel receiver/amplifier will be the front system. The Marantz model 2440 quadradial adaptor amplifier converts any stereo system with tape source monitor feature to a full featured 4-channel system. The 2440 incorporates Marantz's exclusive vari-matrix circuit which simulates 4-channel sound from normal 2-channel stereo programs, and is capable of reproducing 4-channel sound from any matrix encoded source. The amount of effect is variable and can sound as normal stereo to a wide spacey sound. It will also reproduce any discrete 4-channel program as well as regular stereo and monaural programs. An optional plug-in decoder adapts the 2440 for specific matrix systems such as Columbia's SQ or Electro-Voice Stereo 4. (Not included) Specifications Power output: 20W/ch into 8Ω (stereo) Frequency response: 5Hz to 45kHz Total harmonic distortion: 0.3% Damping factor: 45 Input sensitivity: 150mV (line) Signal to noise ratio: 80dB (line) Channel separation: 30dB (line) Output: 1V (Pre out) Dimensions: 17-1/3 x 5-1/3 x 14-3/8 inches Dimensions: 416 x 146 x 330mm Weight: 9kg Year: 1981 Carefully shipped