Sansui QRX 9001 (1975)

A high-end quadraphonic receiver with built-in oscilloscope and proprietary matrix decoding, introduced in 1975

Overview

The Sansui QRX 9001 is a quadraphonic receiver made by Sansui, introduced in 1975 as the company's top-of-the-line model. It is known for its warm, detailed sound, robust construction, and advanced features for both stereo and 4-channel playback. Designed for serious audiophiles and quadraphonic enthusiasts, it integrates complex decoding technology and a built-in 4-channel oscilloscope for precise speaker alignment.

Specifications

Year of Production1975
Power Output125W per channel (8Ω, min. RMS, 20Hz–20kHz, ≤0.3% THD)
Frequency Response20Hz to 20kHz
Total Harmonic DistortionNo more than 0.3%
Signal-to-Noise Ratio (Phono)70dB
Signal-to-Noise Ratio (Aux)90dB
Input Sensitivity (Phono)2.5mV
Input Sensitivity (Aux)150mV
Damping Factor50
Speaker Impedance4-16Ω
Inputs2 phono, 2 aux, 2 tape, tuner
Outputs2 tape, 4-channel direct out
Tuner SectionAM/FM
Dimensions (W x H x D)21-1/4" x 7-1/2" x 17-1/4"
Weight58 lbs

Design

The QRX 9001 features Sansui’s proprietary QS (Quadraphonic Synthesizer) and SQ (Stereo Quadraphonic) matrix decoding, along with the Sansui Vario-Matrix circuit for 4-channel discrete quadraphonic playback.

Context

As Sansui’s top-of-the-line quadraphonic receiver, the QRX 9001 was positioned at the pinnacle of 1970s surround sound technology. It was considered one of the best quadraphonic receivers ever made, targeting audiophiles who valued both technical precision and immersive audio experiences.

Market

Common issues include failing capacitors in the power supply and decoder boards, as well as dirty controls and switches. Restoration can be expensive and time-consuming, but fully restored examples can sell for $2,000 or more, making it highly sought after by collectors and quadraphonic enthusiasts.

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