Integrated Amplifiers

Although the principal claim to fame for the MA9500 is its increased reservoir capacitance and higher dynamic output over the lookalike MA9000 [HFN Sep '18], in practice there's not a substantial difference. Continuous outputs are 2x420W/8ohm and 2x415W/4ohm for the MA9000 versus 2x430W/8ohm and 2x425W/4ohm for the MA9500. Under dynamic conditions the MA9000 achieved 575W/8ohm, 545W/4ohm and 560W/2ohm via the 8, 4 and 2ohm output taps, respectively, with 935W/1ohm (30.6A) also via the 2ohm tap. Under the same conditions the MA9500 offers 597W, 557W, 582W and 1020W (31.9A) into 8, 4, 2 and 1ohm loads [Graph 1, below]. As before, distortion is well 'buffered' against output level or loading at ~0.0015-0.002% over the first 100W and with frequency from 0.0007%/20Hz to 0.002%/20kHz. Noise is moderately low, yielding an A-wtd S/N ratio of 87.4dB (re. 0dBW) while its frequency response stretches from –0.25dB/20kHz to –3.2dB/100kHz (8ohm tap).

The latest digital board, now based on an ESS9028PRO DAC with its default 'fast' linear phase filter, offers a much reduced 0.0006-0.008% distortion [see Graph 2] from its balanced preamp outputs (4V, with volume at 70%; maximum 16.3V at 94% volume). The preamp response achieves +0.0dB/20kHz, +0.4dB/45kHz and +0.1dB/90kHz with 48kHz, 96kHz and 192kHz media, respectively. The A-wtd S/N ratio remains a respectable 111dB and jitter is low, but not vanishingly so, at <220psec (all sample rates). Encouragingly, the MA9000's premature truncation of low-level detail is 'fixed' in the MA9500 which enjoys a fine ±0.4dB resolution at –100dBFs and ±1.1dB at –110dBFs. So this is more than a 'buffed up' MA9000! PM