ARCAM SA20 Class G Integrated Amplifier

ARCAM SA20 Class G Integrated Amplifier – Class G Stereo Integrated Amplifier

The Arcam SA20 is a stereo integrated amplifier built around Class G amplification, a topology Arcam has refined over decades. Class G runs the output stage from a low-voltage supply at ordinary listening levels, where it behaves with the finesse of a Class A design, and switches in a second, higher-voltage supply the moment the music demands it. The result is an amplifier rated at 90 watts per channel into 8 ohms that stays composed on demanding passages without wasting power as heat at normal volumes.

Alongside five analogue inputs including a moving magnet phono stage, the SA20 carries a 32-bit ESS Sabre DAC fed by coaxial and optical inputs, so a television, streamer or CD transport can connect digitally and use the amplifier’s conversion rather than its own. It is deliberately a two-channel product: no surround decoding, no video switching, just a complete stereo control centre for passive loudspeakers.

Key features

• Class G amplification, 90W per channel into 8 ohms, both channels driven
• 150W per channel into 4 ohms at 1kHz
• ESS9038K2M Sabre DAC supporting PCM up to 24-bit/192kHz over coaxial
• Moving magnet phono input for turntables, switchable to line level
• Five analogue inputs and three digital inputs in total
• Full IP control over Ethernet for integration into control systems

Class G, in plain terms

A conventional Class AB amplifier runs one supply voltage sized for the loudest moment in the music, which is inefficient and generates heat during the quiet majority of listening. Class A sounds superb but wastes even more energy. Class G tracks the signal: at low levels only the low-voltage rail is active and the output devices operate in their most linear region, then the high-voltage rail engages seamlessly for transients and bass peaks. You hear the benefit as an amplifier that sounds relaxed and detailed at evening listening levels yet still controls speakers firmly when a recording gets loud.

Digital and analogue sources

Two coaxial inputs accept PCM sample rates up to 192kHz and the optical input up to 96kHz, at bit depths from 16 to 24 bits, with a choice of seven digital filter types so the presentation can be fine-tuned. The DAC section is specified with a signal-to-noise ratio of 115dB. On the analogue side, three line-level RCA inputs, a front-panel 3.5mm input and the phono stage cover CD players, streamers with analogue outputs and turntables; the phono input follows the RIAA curve within 1dB and provides 21dB of overload margin. A pre-amplifier output allows a separate power amplifier or a subwoofer arrangement to be added later.

Daily operation and integration

A backlit remote control is supplied, a 3.5mm headphone output rated for loads from 16 ohms to 2k ohms covers private listening, and the amplifier can be driven by home control systems thanks to full IP control through its Ethernet port and RS-232 connection. That Ethernet port is for control, not music streaming; the SA20 has no built-in streaming platform, so pair it with a dedicated streamer as a source. Build is a full-width 433mm chassis weighing 9.2kg, with maximum power consumption of 500W.

Choosing speakers and sources

With 90 watts into 8 ohms and a healthy 150 watts into 4 ohms, the SA20 suits the majority of standmount and floorstanding speakers in small to medium rooms. The specification that matters most in matching is not the headline wattage but how an amplifier behaves into real loads across the full 20Hz to 20kHz band, which is exactly how Arcam rates this model, both channels driven at 0.5 percent THD.

For a focused two-channel system built from a turntable, a digital source and one good pair of speakers, the SA20 concentrates its entire budget on amplification quality, and it shows in the specification.