Integrated Amplifiers

As we saw in the Ovation CS 8.3 Black [HFN Dec ’22], which employed an earlier generation of Pascal’s S-PRO2 Class D amp module, AVM’s increased 550W/4ohm rating still amounts to 2x235W/8ohm and 2x470W/4ohm in practice, with 245W, 510W, 930W and 485W achievable under dynamic conditions into 8, 4, 2 and 1ohm loads [see Graph 1, below]. However, while the 8/4ohm power output is unchanged, the CS 8.3 S has better low impedance drive – the Black’s 19.4A maximum current increased to 22A here. Overall gain is also increased to +42.2dB while the A-wtd S/N is boosted from 78.4dB to 82.8dB (all re. 0dBW). This general ‘polishing’ of the Class D design is further reflected in the reduced THD from the Black’s 0.017-0.09% to 0.005-0.085% (all 20Hz-20kHz, re. 10W) while, versus level, THD increases gently from 0.0013%/1W to 0.005%/10W, 0.016%/100W and 0.035%/200W (re. 1kHz/8ohm). Finally, while the Black’s response rolled gently away to –2.6dB/20kHz, the CS 8.3 S is far ‘flatter’ at –0.2dB/20kHz, and –5dB/100kHz.

The digital stage benefits from AVM’s uplift from ES9018 to ES9038 DAC where distortion falls to as low as 0.0009-0.0018% over the top 20dB of its dynamic range [see Graph 2] and jitter is almost entirely eliminated (from 250psec to 5psec here). The 110dB A-wtd S/N ratio (volume set at 2.35V for a 0dBFs balanced XLR output) is improved while, again, the ‘Steep’ and ‘Smooth’ digital filters are linear phase types, the former trading more extensive ringing for a full 83dB stopband rejection and flatter –0.05dB/20kHz, –0.4dB/45kHz and –0.4dB/90kHz responses with 48kHz, 96kHz and 192kHz media, respectively. PM