Integrated Amplifiers

The MA9000’s multifilar-wound transformer-coupled output has been a staple of its high-power amplifiers for decades [MC510, HFN Jun ’08 and MC601, HFN May ’11] and by offering a full 2x420W/8ohm and 2x415W/4ohm it continues its tradition of overwhelming its basic specification (300W in this instance). Under dynamic conditions this improves to 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. Distortion is remarkably unaffected by output level or loading at typically 0.00075-0.001W over the first 100W [see Graph 1] and with frequency from 0.0004%/20Hz to 0.0036%/20kHz. Moreover, McIntosh’s ‘Power Guard’ protection regime is remarkably effective at preventing THD from exceeding 1% no matter how hard the MA9000 is pushed, and the (inner) heatsink temperature holds to 48°C. Noise is moderately low, yielding an A-wtd S/N ratio of 88.1dB (re. 0dBW) while its freq. response reaches –0.25dB/20kHz and –3.35dB/100kHz (8ohm tap).

The digital board, based on an ESS9016 Sabre DAC with a standard linear phase filter selected by McIntosh, offers a moderate 0.002-0.012% distortion (20Hz-20kHz, 0dBFs) from its fixed preamp outputs (2.15V), with a minimum of 0.0009-0.003% at –20dBFs [see Graph 2] and with response limits of +0.3dB/20kHz, +0.6dB/45kHz and –8.3dB/90kHz with 48kHz, 96kHz and 192kHz media, respectively. The A-wtd S/N ratio is a respectable 110dB and jitter suitably suppressed at <90psec (all sample rates) but low-level resolution is effectively muted below –100dBFs [again, see Graph 2]. Top-billing here is the analogue amp and autoformer, rather than the partnering DAC stage. PM

Continuous power (<1% THD, 8/4ohm): 420W / 415W
Dynamic power (<1% THD, 8/4/2/1ohm): 575W / 545W / 560W / 935W
Output impedance (20Hz–20kHz): 0.152–0.195ohm (150ohm, pre)
Freq. resp. (20Hz–20kHz/100kHz): –0.28 to –0.25dB/–3.35dB
Digital jitter (S/PDIF at 48kHz/96kHz): 90psec / 65psec
A-wtd S/N ratio (re. 0dBW/0dBFs): 88.1dB (Analogue) / 110.3dB (Dig)
Dist. (20Hz-20kHz; 0dBW/–20dBFs): 0.0004–0.004%/0.0009–0.003%
Power consumption (idle/rated o/p): 61W / 1180W (1W standby)
Dimensions (WHD) / Weight: 445x240x559mm / 45.8kg
Price: £12,995