Интегральные усилители — Yamaha A-S301

The Yamaha A-S301 is a two-channel Class AB integrated amplifier that combines an analogue preamplifier, a moving magnet phono stage and a built-in digital to analogue converter in one full-width chassis. It belongs to the range that also includes the A-S501, A-S701 and A-S801 and shares their ToP-ART circuit philosophy, in which the signal runs from input to output along a direct, symmetrical layout.

Key specs that matter

Minimum RMS output is 60 W per channel into 8 ohm across 20 Hz to 20 kHz at 0.019% THD, and around 70 W into 4 ohm. Dynamic power per channel is listed at 100, 120, 140 and 150 W into 8, 6, 4 and 2 ohm respectively. Frequency response runs from 10 Hz to 100 kHz within 1.0 dB, the damping factor is 210, the signal to noise ratio is quoted at 99 dB and channel separation is 65 dB at 1 kHz. The converter is a Texas Instruments PCM5101 rated for 24-bit and 192 kHz signals and fed by one optical and one coaxial input. The case measures 435 x 151 x 387 mm and weighs about 9 kg.

Engineering and use context

Yamaha builds the amplifier on its ART Base chassis, which adds a solid centre bar for rigidity and vibration damping. A custom power transformer, block capacitors and extruded aluminium heat sinks are used, together with a one point grounding system and two direct signal path speaker relays. Pure Direct mode sends the music signal along the shortest possible circuit route and bypasses the tone section. A continuously variable analogue loudness control is also fitted. Inputs are chosen with a rotary encoder and indicator LEDs, and the aluminium fascia carries a silver hairline finish. An Auto Power Standby function switches the unit off after 8 hours without operation, and the supplied remote handset also has a hairline finish. The line-up of analogue connections totals six inputs, counting the phono socket, plus one analogue output for a recorder.

Pairing

Two sets of speaker terminals can be selected as A, B or A+B, so a second pair of loudspeakers can be driven from the same amplifier. A subwoofer terminal provides a line feed for a powered woofer. Owners of a vinyl deck with an MM cartridge can plug it straight into the phono stage, while the optical and coaxial connections take the digital output of a TV or Blu-ray player. Bluetooth playback needs the optional YBA-11 wireless adapter from Yamaha.

Alternatives

The Yamaha A-S501 is a higher-powered model in the same A-S series of stereo integrated amps.