Sansui AU-6500
An integrated amplifier from Sansui’s classic lineup, featuring low-distortion transistor design and comprehensive audio controls.
Overview
The Sansui AU-6500 is an integrated amplifier produced by Sansui Electric Co., Ltd., recognized as a classic model in the brand's history. It combines a preamplifier and power amplifier in one unit, offering precise audio control and robust performance. Designed during the height of Japanese high-fidelity engineering, it features a fully transistorized signal path with attention to low noise and high dynamic range.
Specifications
| Rated continuous power (20 Hz - 20 kHz, both channels driven) | 28W + 28W (8 Ω) |
| Rated continuous power (1 kHz, both channels driven) | 30W + 30W (8 Ω) |
| Rated continuous power (1 kHz, single channel driven) | 32W (8 Ω) |
| Music power (IHF) | 94W (4 Ω, 1 kHz) |
| Total harmonic distortion (at rated output) | ≤ 0.1% |
| Intermodulation distortion (SMPTE, 70 Hz:7 kHz = 4:1) | ≤ 0.1% |
| Power bandwidth (IHF, 8 Ω, single channel) | 5 Hz - 40 kHz |
| Frequency response, Phono (RIAA deviation, 1W output) | 30 Hz - 15 kHz ±0.5 dB |
| Frequency response, Aux (1W output) | 10 Hz - 30 kHz ±1.0 dB |
| Frequency response, Main In (1W output) | 10 Hz - 40 kHz ±1.0 dB |
| Damping factor | 40 (8 Ω) |
| Input sensitivity/impedance, Phono1 & 2 | 2.5 mV / 50 kΩ |
| Input sensitivity/impedance, Tuner/Aux/4ch Adaptor/Tape | 100 mV / 50 kΩ |
| Input sensitivity/impedance, Main In | 800 mV / 40 kΩ |
| Phono maximum allowable input | 300 mV (for THD ≤ 0.5%) |
| Output voltage, Tape Rec (Pin/DIN) | 100 mV / 30 mV |
| Output voltage, 4ch Adaptor | 100 mV |
| Output voltage, Pre Out | 0.8 V (THD ≤ 0.08%), 4.0 V max (THD ≤ 0.5%) |
| Signal-to-noise ratio (IHF), Phono | ≥ 70 dB |
| Signal-to-noise ratio (IHF), Tuner/Aux | ≥ 80 dB |
| Signal-to-noise ratio (IHF), Main Amp | ≥ 100 dB |
| Tone control, Bass | ±15 dB at 50 Hz |
| Tone control, Treble | ±15 dB at 15 kHz |
| Loudness contour (at -30 dB volume) | +10 dB at 50 Hz, +8 dB at 15 kHz |
| Low filter | -12 dB at 50 Hz (6 dB/octave) |
| High filter | -12 dB at 10 kHz (6 dB/octave) |
| Muting | -20 dB |
| Power consumption | 65 W (125 VA max) |
| Dimensions (W x H x D) | 440 x 140 x 322 mm |
| Weight | 11.5 kg |
| Original price | ¥59,900 (circa 1973) |
Design
The power amplifier uses a pure complementary symmetry, direct-coupled, all-stage PNP-NPN power transistor design to achieve low distortion. The power supply includes a large transformer and two 6,800 µF capacitors. The phono equalizer circuit employs low-noise transistors in a PNP-NPN-PNP configuration for wide dynamic range and minimal noise. A protection circuit combines a transistor, diode, and relay, with a short-circuit fuse. The unit also includes tone controls, loudness contour, muting, low/high filters, and a 4-channel adapter terminal.
Context
The AU-6500 is listed as a classic model in Sansui's product history.
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