SANSUI AU-5500

Pre owned. In good condition. Shows visible signs of wear, also visible in the photos. Not supplied with original packaging.

The Sansui AU-5500 is a stereo integrated amplifier designed with dedicated preamplifier and power amplifier sections featuring circuits focused on signal stability and linearity. The power amplifier stage employs a differential circuit with a pair of transistors in the first stage, followed by a three-stage Darlington configuration for drive and complementary power transistors in the output stage.

The phono section uses a high-gain monolithic integrated circuit with substantial negative feedback applied to achieve a linear frequency response and wide bandwidth. The input stage of the equalizer amplifier also employs low-noise transistors and a configuration that avoids using the chassis as a ground reference, improving the stability of the various circuits.

The tone control section provides separate adjustments for bass, midrange and treble, with the possibility of completely bypassing the tone control circuit for a more direct signal path. A high-pass filter is also provided to attenuate high-frequency noise and interference, together with a low-pass filter designed to reduce very low-frequency noise, such as that caused by grounding problems or vibrations.

The power supply uses a generously sized transformer with good regulation characteristics. Separate regulated power supply circuits are provided for the phono and tone control sections, helping to maintain stable operating conditions for the preamplifier circuits.

The power amplifier protection system combines an electronic circuit, a dedicated relay and a fuse. The system monitors the temperature of the power transistors and detects abnormal voltages, intervening to protect the loudspeakers. The circuit also helps eliminate the impulse noise normally associated with switching the amplifier on.

The AU-5500 features two tape monitor circuits, allowing two tape recorders to be connected and enabling tape-to-tape copying from Tape 1 to Tape 2 and vice versa. It also includes a Loudness control for low-volume listening, a muting function with 20 dB attenuation, and a selector for stereo or monaural operation.

The output section allows the connected loudspeakers to be selected via terminals A, B or A+B, with the option of completely switching off the speaker outputs. The amplifier also features a selector for separating the preamplifier and power amplifier sections, a DIN socket, a large ground terminal and an additional AC power outlet.

Technical specifications:

• Type: stereo integrated amplifier (pre-main amplifier)
• Output power, both channels: 30 W + 30 W into 8 Ω, 20 Hz–20 kHz; 35 W + 35 W into 8 Ω, 1 kHz
• Output power, single channel: 38 W into 8 Ω, 1 kHz
• Music power: 130 W into 4 Ω, 1 kHz
• Total harmonic distortion: preamplifier ≤ 0.1%; power amplifier ≤ 0.1%; overall ≤ 0.15%
• Intermodulation distortion (70 Hz : 7 kHz = 4 : 1, SMPTE): preamplifier ≤ 0.1%; power amplifier ≤ 0.1%; overall ≤ 0.2%
• Power bandwidth (IHF): 5 Hz–30 kHz
• Frequency response (at 1 W output): 10 Hz–35 kHz, +0.5/-1 dB
• RIAA deviation (30 Hz–15 kHz): ±0.5 dB
• Damping factor: 30 at 8 Ω
• Input sensitivity/impedance: Phono 2.5 mV/50 kΩ; Tuner, AUX, Tape Monitor (RCA/DIN) 100 mV/50 kΩ; Main Amp 800 mV/50 kΩ
• Phono maximum allowable input (THD <0.2%): 200 mV
• Output voltage at 1 kHz: Tape Rec (RCA/DIN) 100 mV/30 mV; Pre Amp 800 mV
• Channel separation at 1 kHz: Phono ≥50 dB; Tuner/AUX, Tape Monitor ≥55 dB; Main Amp ≥60 dB
• Signal-to-noise ratio (IHF): Phono ≥70 dB; Tuner, AUX ≥85 dB; Main Amp ≥100 dB
• Tone controls: Bass ±13 dB at 50 Hz; Midrange ±5 dB at 1 kHz; Treble ±13 dB at 15 kHz
• Loudness (at volume -30 dB): +10 dB at 50 Hz; +8 dB at 10 kHz
• Low-pass filter: 70 Hz, -3 dB, 6 dB/octave
• High-pass filter: 7 kHz, -3 dB, 6 dB/octave
• Muting: -20 dB
• Rated power consumption: 70 W
• Dimensions (W × H × D): 434 × 130 × 315 mm
• Weight: 10.4 kg