This legendary piece of vintage high-end audiophile equipment doesn’t need much explanation. Lots of info to find on the net. The Quad 306 is a high quality stereo power amplifier primarily intended for use in very high quality sound reproducing systems. It would normally be used in conjunction with a Quad control unit though other signal sources could be accommodated. The 306 uses a current dumping output circuit, a Quad invention which eliminates many of the problems associated with transistor amplifiers, and is covered by patents in several countries. In a current dumping amplifier there is in effect both a low power very high quality amplifier and a high power heavy duty amplifier. The low power amplifier controls the loudspeakers at all times calling on the high power amplifier to provide most of the muscle. The low power amplifier is so arranged - it carries an error signal - that provided the larger power transistors (the current dumpers) get within the target area of the required output current it will fill in the remainder accurately and completely. The reproduced quality is solely dependent on the small amplifier which because of its low power can be made very good indeed. Specifications Power output: 50 watts per channel into 8Ω (stereo) Frequency response: 13Hz to 40kHz Total harmonic distortion: 0.03% Input sensitivity: 0.375V Signal to noise ratio: 105dB Dimensions: 321 x 64 x 207mm Weight: 4.62kg Little signs of use. pictures are also part of the description. Including high quality gold plated banana speaker plugs and new power cable. If you win the pre-amp too, (see my other auctions) I'll refund shipping costs of the other items. Carefully insured shipped.