Tested with a Rohde & Schwarz

UPL audio analyser 

MEASURED PERFORMANCE

Frequency response at 44.1kHz sample rate (CD) measured flat to 20kHz, our analysis below shows. With 96kHz sample rate the limit was a constrained 30kHz, not the 48kHz possible. However, although the increase in bandwidth isn’t great the rate of roll off was slow and analogue like.

The DAC was very linear, producing  a very low value of 0.16% distortion at 16bit resolution, -60dB (see below), falling to 0.16% with 1LSB of dither applied in our Rohde & Schwarz digital signal generator.

At 24bit resolution the Naim DAC measured just 0.04% at -60dB – as good as it gets. EIAJ Dynamic Range with CD was a high 100dB because of the high linearity. Output was a normal Philips standard 2.15V.

Jitter from USB was very low our anlaysis below shows, a -60dB signal inducing just 20pS of signal related jitter, less than 10pS random jitter and 22pS of low rate clock drift – all very low values, making the ND5 XS a very low jitter source. 

The VHF/FM section of the tuner module uses Software Defined Radio techniques and possessed a performance fairly typical of the (budget) breed. Frequency response was reasonably flat to 11kHz, but exhibited the undulations of digital filtering (see below). A hard cut-off above 12kHz eliminates all higher frequencies.

Distortion was high (2.5%) at full modulation on Left and Right, but low (0.1%) in the Mono (L+R) channel. At 50% modulation the figures had fallen to around 0.3% of 2nd and 3rd harmonic, more reasonable but still high.

Hiss was very high at -56dB (IEC A weighted) and will be audible; analogue tuners typically manage -62 to -72dB. Sensitivity was good, however.

Naim’s on-board DAC gave very good results and is well able to resolve high definition audio. Jitter was very low too. The VHF tuner was an SDR solution of mediocre quality though, afflicted by hiss and not for critical listeners measurement revealed. NK

DIGITAL TO ANALOGUE CONVERTOR

Frequency response (-1dB)

2Hz-30kHz

Distortion (16bit)  %

0dB          0.0007

-6dB         0.0005

-60dB       0.16

-80dB       2

Separation (1kHz)          112dB

Noise (IEC A)               -108dB

Dynamic range (EIAJ)    100dB

Output                           2.1V

VHF/FM

Frequency response      10Hz-11kHz

Stereo separation           28dB

Distortion (50% mod.)     0.3%

Hiss (CCIR)                   -56dB

Signal for minimum hiss   0.6mV

Sensitivity

mono                            5µV

stereo                           42µV

FREQUENCY RESPONSE (what it means)

DISTORTION  (what it means)

JITTER  (what it means)

VHF/FM FREQUENCY RESPONSE  (what it means)