NAD C 700 Streaming Amplifier Lab Report

Lab Report

If the C 700 looks like a scaled-down M10 [HFN Jun '19] then, in key respects, it is – the latter's ES9028 DAC replaced by an ES9010 here just as the Ncore amp module is exchanged for a more cost-effective UcD102 in the C 700. The M10 and C 700 are rated at 100W and 80W/8ohm, respectively, and while the former has the edge in continuous power at 100W/8ohm and 200W/4ohm vs. 95W/130W from the C 700, the little newcomer has a more impressive and load tolerant dynamic performance at 121W, 226W, 302W and 196W into 8, 4, 2 and 1ohm loads [see Graph 1, below]. As we saw in the M10, all digital and analogue inputs are managed digitally and finally passed to the UcD amps after D/A conversion at 48kHz/24-bit, so the response of the power amp is limited to –0.3dB/20kHz (and –2.5dB/21kHz) regardless of the incoming sample rate.

The preamp outs, however, extended to within ±0.2dB at 20kHz, 45kHz and 90kHz with 48kHz, 96kHz and 192kHz digital inputs, respectively. The digital filter is a standard linear phase type while jitter is very low at less than 12psec with 48kHz/24-bit files and typically ~10psec at 96kHz/192kHz. The A-wtd S/N is wider, relatively, via the preamp than the power amp outputs (the former 106.1dB, but the latter at 79.1dB re. 0dBW is a little below average) though distortion is tightly managed in the UcD amps at 0.003-0.01%/1W and 0.009-0.025%/10W (all 20Hz-20kHz). Via USB in/pre out, THD is as low as 0.0004% through bass and mid over the top 30dB of its dynamic range [black trace, Graph 2] but is uniformly higher at 20kHz – a minimum of 0.0025% – over the top 20-30dB of its dynamic range [blue trace]. Linearity is true to ±0.1dB over a 100dB range. PM


Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max. current is 14.0A


Distortion versus 24-bit digital signal level over a 120dB range (1kHz, black; 20kHz, blue)

Continuous power (<1% THD, 8/4ohm) 95W / 130W
Dynamic power (<1% THD, 8/4/2/1ohm) 121W / 226W / 302W / 196W
Output imp. (20Hz–20kHz, Pre/Amp) 95-115ohm / 0.07-0.09ohm
Freq. resp. (20Hz-20kHz/45kHz/90kHz) –0.0 to –0.1dB/+0.2dB/–0.2dB
Digital jitter (USB / S/PDIF) 12psec / 10psec
A-wtd S/N ratio (Digital/Amplifier) 106.1dB (0dBFs)/79.1dB (0dBW)
Distortion (20Hz-20kHz, Digital/Amp) 0.0007-0.0013%/0.009–0.025%
Power consumption (idle/rated o/p) 18W/200W (1W standby)
Dimensions (WHD) / Weight 218x96x266mm / 4.8kg
Price £1299

NAD Electronics International
Supplied by: Sevenoaks Sound and Vision, UK
01732 740 944