Integrated Amplifiers

Power output is on-target, prodigious [see boxout] and unaffected by choice of either analogue (line) or digital (USB or optical) inputs, although the former’s bandwidth is limited to <1Hz-39kHz (re. –3dB) because of the input ADC’s 96kHz sampling. The core 192kHz sampling of the ADH amplifier realises a <1Hz-87kHz response with high rate digital inputs where distortion is also slightly lower – 0.0003% versus 0.001% (all re. 1kHz/10W/8ohm). Versus frequency, distortion is also commendably flat at just 0.00015-0.004% [pink trace, see Graph below] – the slight rise at HF is inevitable but not shown in Devialet’s own supporting graphs because (read the small print!) it used a 20kHz bandpass filter during its measurements. This has the effect of removing any harmonics above 20kHz that would otherwise contribute to the overall result. Treating the Astra as a ‘power DAC’ [Graph below] allows its distortion vs. digital level to be mapped as we would in any HFN streamer/DAC review except here the output is 160W/8ohm (and not a typical DAC’s 2V or 4V) at both 1kHz [black trace] and 20kHz [blue trace] at 0dBFs. With the Astra’s volume set to ‘0.0’, its power output with a –20dBFs digital input is therefore 1.6W/8ohm.

Otherwise the Astra easily meets or exceeds its other performance parameters. The output impedance is closer to 0.002ohm than the specified 0.004ohm, so the ‘damping factor’ is twice Devialet’s figure, ensuring the Astra is unaffected by changes in loudspeaker load. Noise is fabulously low too, rewarding the Astra with a super-wide 96.5dB A-wtd S/N ratio (re. 0dBFs input and 0dBW output) just as the channel separation is >130dB through the midband (90dB at 20kHz). PM