Phono Preamplifiers

Tested via its MM/RCA and two MC/XLR inputs, and partnering balanced XLR outputs, the Asterion V2’s notional +46dB, +70dB and +76dB gain settings are, in practice, +53.1dB, +77.3dB and +82.5dB, respectively. Used via the RCA line outputs, the MM gain falls back by 6dB to 47dB, so these are perfectly ‘useable’ figures amounting to sensitivities of 2.2mV (XLR out) and 4.4mV (RCA out, all re. 0dBV). The high voltage 6922EH tube-based RIAA stage also endows the Asterion V2 with a very substantial 19V maximum output (re. 1kHz/1% THD) but because the gain is fixed – there’s no volume control here – and because the passive eq. section soaks up a lot of headroom, the input overload margin is necessarily limited. For the MM stage this amounts to 49mV which is +27dB (re. 2.2mV input sensitivity) or +19.9dB (re. standard 1kHz/5cm/sec), both sufficient to accommodate the maximum groove excursions likely to be encountered in practice.

Audiophiles need to be more mindful with MC pick-ups deployed in balanced mode, and via the balanced XLR outputs, because the high gain of the MC1 and, in particular, the MC2 input yields exceptionally high sensitivities allied to restricted input overload margins [see boxout, p59]. This is a pity because the Asterion V2 has otherwise been expertly engineered to achieve a fabulous A-wtd S/N of 91dB in MM mode and 89dB in MC1/MC2 modes. These are state-of-the-art figures, and all the more impressive bearing in mind the high gain. Distortion [see Graph 2, below] is well managed too – just 0.016-0.08% (20Hz-20kHz, re. 0dBV) – while the RIAA-corrected response is true to ±0.6dB from 20Hz-100kHz [see Graph 1, below]. The optional subsonic filter includes a 3rd-order roll-off below 18Hz, reaching to –3dB/14Hz and –9dB/9Hz [dashed trace, Graph 1].

RIAA-corrected frequency response from 5Hz-100kHz (subsonic filter, dashed trace; balanced o/p)

Distortion versus frequency re. 0dBV from 5Hz-40kHz (MM input, balanced output)