Phono Preamplifiers

The Nu-Vista Vinyl S allows for two groups (MM and MC) of four gain settings, in 3dB increments, although the practical gain is +6dB higher than we saw in the Vinyl 2 when tested via the balanced XLR in/outs [see boxout]. As a result, the 40-49dB settings amount to +46dB, +49dB, +52dB and +55dB, handling MM pick-ups of 5.0mV, 3.55mV, 2.53mV and 1.79mV output (re. 1kHz/5cm/sec), respectively, to deliver 0dBV from the Vinyl S.

The MC gain options range from +60dB to +69dB (+66.5dB, +69.4dB, +72.4dB and +75.3dB, in practice) and will match lower output MCs over a 473-171μV specification. Higher output MCs are still perfectly ‘useable’ at the +60dB (+66.5dB) setting, of course, thanks to the 70dB A-wtd S/N ratio (re. 500μV input) and useful 10mV input overload – equivalent to a very healthy margin of 26.5dB relative to the baseline 473μV sensitivity.

That 70dB A-wtd S/N ratio is consistent across all four MC gain settings, as is the higher 81.0dB (re. 5mV input) across the quartet of MM options. The RIAA-corrected response is good to within ±0.15dB from 20Hz-20kHz, rolling off gently to –3dB/5Hz and –1.4dB/100kHz. The ‘Mild’ subsonic filter [blue, Graph 1] adopts the IEC profile, rolling off below 100Hz to –3dB/25Hz and –6dB/15Hz while ‘Standard’ [red trace] has a +0.7dB lift at 25Hz with a steep roll-off thereafter. Distortion via the MM input falls to as low as 0.0012%/1kHz before increasing to 0.01%/20kHz [black infill, Graph 2] while the extra gain of the MC stage adds a little distortion to the tune of 0.004-0.045% [20Hz-20kHz, red infill, Graph 2]. Across all gain settings, and over the full 20Hz-20kHz audio bandwidth, distortion remains markedly lower than might be expected from the very finest MM/MC pick-ups. PM