DescriptionThe Quad 909 is a two channel power amplifier using current dumping technology. It weighs approximately 12kg and is built to be robust. The performance of the 909 amplifier is as accurate as it is possible to achieve by careful design, selection of components and rigorous test procedures. The unit has no controls other than a power switch (which is normally left on) and may be mounted out of sight in a cabinet or other convenient location. To keep BUS connections simple you can place the unit below the 99 preamplifier. Power amplifiers can be placed alongside or out of sight using a long 99 AMPBUS cable. The amplifier is full compatible with the ESL-63, ESL-988 and ESL-989 loudspeakers but it should not be used with the earlier model ESL which could be damaged by signal peaks unless a protection circuit is fitted in the loudspeaker.SpecificationsPower output: 140 watts per channel into 8Ω (stereo)Frequency response: 13Hz to 40kHzTotal harmonic distortion: 0.01%Input sensitivity: 0.775VSignal to noise ratio: 108dBSpeaker load impedance: 4Ω (minimum)Dimensions: 321 x 140 x 240mmWeight: 12kg