Rohde & Schwarz UPV audio analyser, used for all measurements.

MEASURED PERFORMANCE

Frequency response measured flat to 22kHz with a  48kHz sample rate test signal and to 40kHz (-1dB) with a 192kHz sample rate test signal from our Rohde & Schwarz UPV signal analyser, via both electrical and optical S/PDIF inputs. Our response graph shows a slow roll off up to 85kHz (-5dB) then a steep decline imposed by anti-alias filtering above 90kHz.

The three filter settings made little difference to this result, although Steep had a very minor effect, but it neither altered pass band nor stop band amplitude characteristics in any significant way (they alter phase and pulse pre-ringing). Output was free from spuriae up to 250kHz whatever filter was selected. The unbalanced phono socket output delivered 2.1V and the XLR balanced output 4.2V.

Distortion at -60dB was 0.22% with a 16bit signal, as expected, and 0.04% with a 24bit signal, both very good results showing the Stream Magic 6 is linear. Our distortion analysis clearly shows second harmonic predominates too, with 24bit resolution.

Noise was low with 24bit and Dynamic Range very high at 114.5dB, using a -60dB test tone notched out to lift output muting. In fact, noise sinks no lower with digital zero output muting, with 24bit, but 16bit quantisation generates 14dB of noise.

The Stream Magic 6 DACs resolve high definition audio fully, giving a very good measured performance in every area. NK

Frequency response (-1dB)       2Hz-40kHz

Distortion (24bit)   %

0dB                 0.0008

-60dB                 0.04

Separation (1kHz)               135dB

Noise (IEC A)                    -114dB

Dynamic range (24bit)         114dB

Output (phono/XLR)         2.1/4.2V

FREQUENCY RESPONSE, 24/192, S/PDIF

DISTORTION, -60dB, 24bit