909

About the 909

The Quad 909 is a versatile power amplifier designed to work seamlessly with high-quality stereo preamplifiers, particularly those from the Quad 99 series. It features a unique current dumping circuit that combines the sound quality of a low-power class A amplifier with the power delivery of a high-current class B amplifier. This design eliminates issues like crossover distortion and thermal tracking, ensuring consistent performance without the need for fine-tuning adjustments. The amplifier is compact, weighing approximately 12 kg, and is built into a robust casing. It is well-suited for use with speakers like the ESL-63, ESL-988, and ESL-989 but should not be used with earlier ESL models without protection circuits.