PS Audio Stellar Gain Cell DAC & Stellar M700 DAC/Preamp/Monoblocks Lab Report

Lab Report

Although PS Audio has adopted the tried-and-tested ES9018 DAC, the usual mix of low noise, low distortion and vanishingly low jitter are swamped here by PSU noise and THD from, presumably, the encapsulated 'Gain Cell' preamp. The A-wtd S/N is 90dB (re. 0dBV, or just 103dB via the DAC at the maximum 6V balanced output) while distortion is a steady 0.016% on the left, 0.0095% on the right, from 20Hz-20kHz. The 'Gain Cell' itself offers a maximum +12dB gain, delivering up to 19.9V from a 97ohm source impedance via its balanced outputs. Add the DAC into the signal path and distortion reaches 0.09-0.11% at 0dBFs with a minimum of 0.005-0.02% over the top 30dB of its dynamic range [see Graph 2, below]. The ES9018 DAC is capable of far lower than the ~3000psec jitter/PSU intermodulation recorded here, and this will surely add some fuzzy warmth to the Stellar DAC's sound.

The 76.1dB A-wtd S/N ratio (re. 0dBW) of the partnering M700 monoblocks suggests they're no 'quieter' than the pre, but this is an innocuous white noise. Otherwise the M700 is deceptively powerful, matching its 700W/4ohm rating at 365W/8ohm and 715W/4ohm, the Class D architecture yielding little or no difference under dynamic conditions at 366W, 725W and 750W into 8, 4 and 2ohm, falling to 495W/1ohm as a result of its 22A current limit [see Graph 1, below]. This and the trend of gently rising distortion above 10W (0.0009%/10W to 0.005%/100W, 0.011%/200W and 0.022%/300W) is also visible in Graph 1 (albeit lower under continuous than dynamic conditions). PM


Dynamic power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue) and 1ohm (green) speaker loads. Max. current is 22.3A


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

Continuous power (<1% THD, 8/4ohm) 365W / 715W
Dynamic power (<1% THD, 8/4/2/1ohm) 366W / 725W / 750W / 495W
Output imp. (20Hz–20kHz, Pre/Amp) 97ohm / 0.011-0.022ohm
Freq. resp. (20Hz–20kHz/100kHz) –0.09 to –0.5dB/–8.9dB
Digital jitter (USB / S/PDIF) 3050psec / 3150psec
A-wtd S/N ratio (DAC/Amp) 102.7dB (0dBFs) / 76.1dB (0dBW)
Distortion (DAC, 0dBFs/Amp, 0dBW) 0.085–0.095% / 0.0009–0.008%
Power consumption (Preamp/Amp) 7W / 402W (19W idle)
Dimensions (WHD, each unit) 432x76x305mm / 21kg (total)
Prices (DAC/Preamp & Monoblocks): £1550/£2700

PS Audio
Boulder, Colorado
Supplied by: Signature Audio Systems
07738 007776