Интегральные усилители — Yamaha A-S501

The Yamaha A-S501 is a stereo integrated amplifier in the A-S series, placed between the A-S301 and A-S701. Yamaha describes it as an integrated amplifier with the advantage of digital input, combining an MM phono stage and analogue line inputs with optical and coaxial digital connections for a TV or Blu-ray player.

Key specs that matter

Yamaha specifies a minimum RMS power of 85 W per channel into 8 ohms from 20 Hz to 20 kHz at 0.019% THD, while for Europe the maximum is given as 120 W per channel into 4 ohms at 1 kHz and 0.7% THD. Dynamic power per channel is 130 W into 8 ohms, 150 W into 6 ohms, 185 W into 4 ohms and 220 W into 2 ohms. Frequency response covers 10 Hz to 100 kHz within 1 dB. Distortion from the CD input to the speakers is 0.019% at 50 W into 8 ohms, and the CD input noise figure is 99 dB with the input shorted at 200 mV. Damping factor is 240, compared with 210 for the smaller A-S301. In total the rear panel carries eight audio inputs and two audio outputs. The unit measures 435 x 151 x 387 mm and weighs 10.3 kg, the same footprint as the A-S301 and A-S701.

Engineering and use context

The A-S501 is built on ToP-ART, short for Total Purity Audio Reproduction Technology. Its I/O Direct Symmetrical Design routes the signal in a straight line from input to output, and the ART Base (Anti-Resolution and Tough) adds a rigid mounting structure under the chassis. Parts include a custom-made power transformer, 12,000 microfarad block capacitors and extruded aluminium heatsinks. A Pure Direct mode bypasses the tone circuits for a shorter signal route, and a continuously variable loudness control is fitted. The front panel is aluminium, in keeping with the simple styling of the range. On Yamaha's comparison table, the A-S501 shares Pure Direct, ToP-ART, digital inputs and the subwoofer and DC outputs with the A-S301 and A-S701. Auto Power Standby switches the unit off when it is left unused, and standby consumption is 0.5 W.

Pairing

The speaker terminals are gold-plated, as are the CD and phono RCA sockets and the coaxial digital input. A dedicated subwoofer output is provided, and a DC output can trigger other equipment. The phono socket is intended for record decks using MM pickups, while the digital inputs take a television or disc player with an optical or coaxial output.

Alternatives

A step higher in the same line, the Yamaha A-S701 is rated at 100 W per channel RMS into 8 ohms and adds switchable CD Direct Amplification.