Integrated Amplifier Yamaha A-S501 Black

Integrated amplifier with ToP-ART architecture and digital inputs for TV and Blu-ray

The Yamaha A-S501 is an integrated stereo amplifier built on the ToP-ART (Total Purity Audio Reproduction Technology) concept, which combines an analogue signal path with the ability to connect digital sources. The power section delivers 85 W + 85 W RMS into 8 ohms at 0.019 % THD, or 120 W + 120 W into 4 ohms, with dynamic power of 130/150/185/220 W depending on the load impedance. Thanks to its optical and coaxial digital inputs, it allows direct connection of a television or Blu-ray player without the need for an external converter.

The design is based on I/O Direct Symmetrical Design, i.e. a symmetrical layout of the left and right channels in a straight line from input to output, which shortens the signal path and reduces the risk of interference. The bottom of the chassis is formed by the ART (Anti-Resonance and Tough) Base with a central reinforcing beam that increases the rigidity of the whole unit and damps vibrations. The power supply and output stage feature a custom-made power transformer, 12,000 µF block capacitors, extruded aluminium heat sinks, two relays switching the direct signal path to the speakers, and single-point grounding.

The Pure Direct mode routes the signal along the shortest possible path, bypassing the buffer amplifier as well as the tone control, loudness and balance circuits, resulting in lower distortion and cleaner detail reproduction. The continuously adjustable analogue loudness control with electronic volume control compensates for the reduced perception of frequency extremes at low listening levels, so tonal balance is maintained even during quiet playback. A signal-to-noise ratio of 99 dB (CD), a frequency response of 10 Hz – 100 kHz ±1.0 dB and a damping factor of 240 contribute to stable control of bass drivers and precise instrument localisation.

Connectivity covers eight analogue inputs including an MM phono input for a turntable, two outputs, a subwoofer output and a DC-out for powering the YBA-11 wireless adapter with aptX support. The terminals allow two pairs of speakers to be connected with A, B or A+B switching. Gold-plated speaker terminals, RCA connectors (CD, Phono) and the coaxial terminal minimise transition losses. The brushed aluminium front panel is complemented by a rotary input selector with LED indication and the Auto Power Standby function, which switches the unit into standby mode with 0.5 W consumption after approximately eight hours of inactivity.

Key features

• Power: 85 W + 85 W RMS into 8 ohms, 0.019 % THD
• ToP-ART: Symmetrical signal path and ART Base chassis
• Digital inputs: Optical and coaxial input for TV and Blu-ray
• Pure Direct: Bypasses tone controls and buffer for a pure signal
• Connectivity: MM phono, subwoofer out, two pairs of speakers