Two common problems can arise with hi-fi amplifiers, based on the choice of amplification class.
Class A (the traditional audiophile’s choice) uses a single power supply constantly running at full capacity, even when there’s no signal coming through. Whilst this is great for reproducing subtle details at low levels, this kind of system can struggle to deliver extreme power when needed.
Class A/B (the most common amplification class) instead switches between TWO internal amplifiers, one for each half of the audio waveform. This is far more efficient but often a recipe for crossover distortion, as low-level details may get lost within any mis-match where the two amplifiers switch over.
Class G amplifiers solve these problems in a very elegant manner. Essentially the Arcam SA20 is a hybrid amp which utilises Class A specifically for low-level signals, then switches in an additional power supply to drive those larger sections of the waveform, as & when needed. Very neat.
- Class G amplification for impeccable sound and efficiency
- 90W of power per-channel
- Continuous power per-channel (both channels) 80W
- Continuous power per-channel (one channel) 176W
- Class A output to 12W
- x5 analogue inputs including phono (x1 line/MM switchable)
- x3 digital inputs (x2 SPDIF, x1 Optical)
- 32-bit DAC (Sabre ESS9038K2M)
- Full I/P control
- Total harmonic distortion + noise = 0.003%