Pre/Power Amplifiers

Tested via its analogue line input, power output, and distortion, rather depend on the position of the volume control because the input ADC (sampling at 48kHz-192kHz/24-bit) clips before the output. At a volume setting of –6.0dB distortion is 0.006% (very close to NAD's specification) but at a volume setting of 0.0dB distortion rises to 0.012%, and at +6.0dB it's 0.025% (all for the same 1kHz/1W/8ohm output). However, with the volume at –6.0dB the maximum power output is just 2x50W/8ohm, while at 0.0dB it is 2x190W into both 8/4ohm (with the 'speaker compensation' set to 8 or 4ohm). While the amplifier is clearly protected against high continuous power outputs into lower impedances, its dynamic output (in traditional NAD style) is generous at 200W and 400W into 8/4ohm loads with a current-protected 433W/167W into 2/1ohm loads [see Graph 1].

In practice the M32 is far better optimised for its digital MDC card where a maximum 2x182W/8ohm is achieved with a peak level 0dBFs digital input and with the volume set to –0.5dB. The amplifier clips at 0.0dB (200W/8ohm at 1% THD) so the volume control should never be advanced beyond this point. The digital input frequency response(s) scale with input sampling rate reaching +0.1dB/20kHz, +2.9dB/45kHz and –8dB/90kHz with 48kHz, 96kHz and 192kHz media, respectively. Distortion (plus noise) is typically <0.01% through bass and midrange frequencies over the top 50dB of its dynamic range [black trace, Graph 2] but increases steeply above 10kHz-20kHz as a result of the modulator's ultrasonic requantisation noise [blue trace]. Jitter is impressive low at 260-300psec from 1-10W output at all incoming sample rates. PM

Continuous power (<1% THD, 8/4ohm): 190W / 190W
Dynamic power (<1% THD, 8/4/2/1ohm): 200W / 400W / 433W / 167W
Output impedance (20Hz–20kHz): 0.005–0.20ohm
Freq. resp. (20Hz–20kHz, 45kHz, 90kHz): –0.2 to +0.1dB / +2.9dB / –7.8dB
Digital jitter (48kHz/96kHz, 0dBW): 262psec / 300psec
A-wtd S/N ratio (re. 0dBW/0dBFs): 84.8dB (Analogue) / 107.2dB (Dig)
Dist. (20Hz-20kHz; 0dBW/–20dBFs) : 0.009-0.27% / 0.002-0.22%
Power consumption (idle/rated o/p): 37W / 400W (4W standby)
Dimensions (WHD) / Weight: 435x133x396mm / 9.8kg
Price: £3499