Phono Preamplifiers

Phono stages with multiple gain and/or loading options often trade versatility for ease-of-use, employing fiddly DIP switches to select between the various options. Not so here – full remote control over MM and MC gain and loading (ok – the variable MC loading is achieved via two analogue pots) is achievable via remote making 'tuning-on-the-fly' so much easier. PS Audio claims +44dB, +50dB and 56dB gain for its MM input and +60dB, +66dB and +72dB for MC, values that are closely matched on test at +43.9dB, +49.3dB and +54.8dB for MM and +59.9dB, +65.4dB and +70.9dB, respectively, for MC (all single-ended in/balanced out). These are well chosen steps, the lowest MM gain offering a 6.4mV sensitivity with the highest MC gain representing 0.29mV (286µV). Moreover, each step is engineered with a generous +25dB input overload margin, sufficient to accommodate the 'hottest' +18dB groove modulation (re. 11.2µm/300Hz), of 166mV, 86mV and 40mV (MM), and 27mV, 14mV and 6.5mV (MC), respectively.

The active/passive RIAA equalisation is also very flat and extended out to 100kHz, with two broad but mild –0.1dB dips either side of 1kHz and a subsonic filter amounting to –6dB/2Hz [black trace, Graph 1]. The RIAA-eq'd distortion [see Graph 2] is not vanishingly low, but with a minimum of 0.0055%/40Hz and a maximum of just 0.071%/20kHz (re. 0dBV) it is still a couple of orders of magnitude lower than the best MM/MCs. Noise is also just below the threshold of most vinyl systems, the 76-80dB A-wtd S/N ratio (MM/MC) more than adequate for the task. The 26V maximum (balanced) output is arguably overkill, but if the Stellar Phono had a volume control it could surely drive any partnering power amplifier directly... PM