Phono Preamplifiers

When Hegel's chief designer, Bent Holter, set about maximising the versatility of the V10 design there was an acceptance that this came at a cost: users would need to negotiate fiddly little DIP switches to select between the various options. The +20dB extra gain that separates MM and MC inputs, and their respective 0dB, +5dB, +10dB and +12dB 'fine gain' settings are all selected via DIP toggles, as are the subsonic filter and the various impedance (MC) and capacitance (MM) loads on offer. Hegel claims +40dB, +45dB, +50dB and +52dB gain for its MM input and +60dB, +65dB, +70dB and +72dB for MC, values that are closely matched on test at +40.3dB, +45.8dB, +50.8dB and +52.8dB for MM and +60.6dB, +66.1dB, +71.1dB and +73.0dB, respectively, for MC (all RCA single-ended in/XLR balanced out).

In practice, the lowest MM gain setting offers a 9.69mV sensitivity but the +5dB option with its 5.16mV sensitivity and very healthy 123mV input headroom will be the best 'default' for high output MMs. Similarly, the 'MC +5dB' setting – a sensitivity of 494µV with an input overload limit of 12.5mV – is ideal for the vast majority of 'coils. Moreover, this excellent range of sensitivities, coupled with at least 27dB of headroom at each step, is complemented by useful A-wtd S/N ratios of 79dB (all MM gain settings) and 78dB (all MC settings).

RIAA equalisation is also very flat and extended out to 100kHz within ±0.25dB, its steep subsonic filter amounting to –3.5dB/20Hz and –13dB/12Hz [see Graph 1]. If you have big, reflex-loaded speakers then this sub filter should be engaged. The RIAA-eq'd distortion [Graph 2] is slightly higher at bass frequencies, although 0.005% is still 100-1000x lower than any vinyl front-end! The minimum of 0.00028%/5kHz is spectacularly low. PM