Quad 405 rear panel and associated PSU sub-chassis parts, sold as-is for spares or repairs. Fully disassembled; not a complete amplifier.

Specifications

• Country of Origin: United Kingdom
• Year Manufactured: 1970s
• Type: Two-channel solid-state power amplifier
• Amplifier Topology: Current-dumping (Class A front-end + Class B output stage with feedforward error correction)
• Power Output: 100 W per channel into 8 ohms
• Speaker Load Impedance: 4 Ω to 16 Ω
• Frequency Response: −1 dB at 20 Hz (12 dB/octave subsonic filter); −0.5 dB at 20 kHz; −3 dB at 50 kHz
• Power Bandwidth: 10 Hz – 20 kHz
• Input Sensitivity: 500 mV for 100 W output
• Input Connector: 4-pin DIN socket (RCA adaptor cable supplied)
• Total Harmonic Distortion (THD): 0.05%
• Signal-to-Noise Ratio: 95 dB
• Damping Factor: 80
• Channel Separation: 85 dB at 1 kHz
• Dimensions (W × H × D): 340 mm × 115 mm × 195 mm (13.4" × 4.5" × 7.7")
• Weight: 9 kg (20 lbs)
• Years of Production: 1975 – 1982 (Quad 405); succeeded by Quad 405-2 (1983–1993)
• Manufacturer: Acoustical Manufacturing Co. Ltd. (later Quad Electroacoustics), Huntingdon, England