Phono Preamplifiers

While not directly compatible with strain gauge pick-ups [HFN Nov '21], the Soulnote E-2 is otherwise the closest example of a 'universal phono preamp' we have tested. As it's not practical to lab test the 'optical' eq block (the pick-up's internal LEDs are powered via the R– and L– pins while the output is returned via R+ and L+), I have focused on the MM/MC stages. The user-selectable high pass (Low Limit), the Turnover and low pass (Roll-off) are immensely flexible, offering no fewer than 144 possible eq curves. The default 50Hz, 500Hz and 2.12kHz settings, respectively, yield an accurate RIAA response [black trace, Graph 1], flat to within +0.3dB/20Hz to –0.2dB/20kHz out to –0.3dB/100kHz. The 'Low Cut' option invokes a mild subsonic filter that reaches –6dB/2Hz [dashed trace, Graph 1]. The 50Hz, 630Hz, 1.59kHz and 150Hz, 630Hz, 6.89kHz extremes of the legacy curves are illustrated by the red and blue traces, respectively, with the RIAA eq function plotted in green [Graph 1].

Soulnote rates the E-2's gain options at +52dB and +72dB for MM and MC, respectively, which turns out to be +47.1dB/56.4dB (MM, low/high gain) and +69.6dB/77.2dB (MC, low/high gain) via the balanced output. This is a very compatible spread, matched by input overload limits of 104mV, 82mV and 9.8mV, 7.7mV for MM and MC – a solid +26dB headroom if used with 5mV/500µV MM/MC pick-ups in the low gain setting. Distortion is more than low enough at 0.0045-0.060% [20Hz-20kHz, re. 0dBV; see Graph 2] while the A-wtd S/N ratios are very fine at 87dB (MM) and 70dB (MC). Finally, Soulnote specifies its balanced XLR output at 2.8V but the maximum output is actually an amp-busting 52V! PM