Sansui AU-555A Stereo Solid-State Hi-Fi Amplifier. The Sansui AU-555A amplifier was manufactured between 1971 and 1973, making it just over fifty years old. I bought it from a previous one-owner in 1975, which means I've had it in my posession for nearly fifty. It's been in consistent and careful use in that whole time and never failed me once. It has been serviced once, as you can see on the photo. The metal sides and front panel are in perfect condition, and the close-up photos show light scratches on the wood panel sides. My only regret is that, although the top wooden panel is near perfect, I was foolishly convinced to engrave my phone number on it (to deter would-be thieves!). You can see it in the photo, in the middle, near the top. It's not too deep, and I'm sure a little tender application of matching colour could lessen the blemish. Very sad to part with this beautiful piece of hi-fi equipment, but the tech needs of today's audio require features such as bluetooth, digital connection to Smart TV, etc, etc. This model amplifier is an outstanding example of a vintage hi-fi stereo amplifier, renown for its sound qualities and reliability. It's a full-function integrated amplifier offering 2x MM phono inputs, 2 line-level RCA inputs, Tape inputs (DIN and RCA), and 2 pairs of spring type speaker terminals for running 2 pair of speakers. The AU-555A can also be used just as a preamplifier or just as a power amplifier by removing the bridge clips at the back. This Sansui's power output is 25wpc into 8 ohms and 33wpc into 4 ohms. On the front panel there's a Power button, 1/4″ phono jack, Speaker selection switches (A and B), Low Filter button (low-frequency noise reduction), High Filter button (high frequency noise reduction), a Loudness switch, Balance control knob, Stereo/Mono operation, Volume, Input Selection, and Tape Monitor. This amplifier has a sleek silver design with a brushed black front panel. It has a sturdily-built one-piece walnut veneered ply cover. Specifications Power output: 25 watts per channel into 8ohms, 33 watts per channel into 4 ohms (stereo) Frequency response: 20Hz to 30kHz Total harmonic distortion: 0.5% Damping factor: 50 Input sensitivity: 2mV (MM), 180mV (DIN), 180mV (line) Signal to noise ratio: 70dB (MM), 80dB (line) Channel separation: 45dB (MM), 50dB (line) Output: 180mV (line), 30mV (DIN) Speaker load impedance: 4Ω to 16Ω Semiconductors: 23 x transistors, 2 x diodes Dimensions: 395 x 127 x 278mm Weight: 8kg