Pre/Power Amplifiers

From the published information it would seem the D 3020's Class D amp modules remain largely unchanged in the V2. But on the basis of my tests, it seems that NAD has 'tweaked' the amp's performance, reducing its output impedance through bass and midrange, increasing its gain by 1dB and significantly reducing noise to yield a wider 93.9dB A-wtd S/N ratio (from 89.1dB). Again, the V2 easily bests its 2x30W specification, delivering 2x50W/8ohm and a similar 2x58W/4ohm (from 60W/65W with the original D 3020) and, despite adopting a Class D architecture, offers enough headroom under dynamic conditions to yield 140W, 215W (from 240W) and 165W (130W) into 4, 2 and 1ohm loads [see Graph 1]. So this diddy box remains considerably more capable, and load tolerant, than you might expect. Where this V2 model differs, however, is in the mapping of distortion vs. level and frequency. THD now increases linearly with output, from 0.012%/1W to 0.15%/10W and 0.3% at the rated 30W/1kHz. Versus frequency, THD now peaks in the midband and falls in the low bass and high treble – 0.02%/20Hz to 0.15%/1kHz and 0.023%/20kHz at 10W.

The new phono stage, meanwhile, is no mere afterthought. It combines a maximum +52dB gain (good for MMs and high output MCs) with a maximum 4.5V preamp output, a generous input overload limit of 99mV (+26dB headroom over a standard 5cm/sec MM output) and a creditable 82.1dB A-wtd S/N ratio. The frequency response is also very extended with –1dB limits at 13Hz and 100kHz [black trace, Graph 2], stereo separation is a full 75dB (1kHz) while distortion falls with frequency from 0.2%/20Hz to 0.012%/20kHz [red infill, Graph 2]. PM

Continuous power (<1% THD, 8/4ohm): 50W / 58W
Dynamic power (<2% THD, 8/4/2/1ohm): 70W / 140W / 240W / 165W
Output impedance (20Hz–20kHz): 0.028-0.1ohm (172-193ohm, pre)
Freq. resp. (Aux, 20Hz–20kHz/100kHz): +0.0 to –0.3dB/–7.6dB
Freq. resp. (MM, 20Hz–20kHz/100kHz): –0.50 to –0.0dB/+1.0dB
A-wtd S/N ratio (Aux/MM): 93.9dB (re. 0dBV) / 82.1dB (re. 5mV)
Distortion (20Hz-20kHz; 0dBW/MM) : 0.009–0.014% / 0.012–0.2%
Power consumption (idle/rated o/p): 12W / 70W
Dimensions (WHD) / Weight: 186x58x219mm / 1.38kg
Price: £400