Alva Solo

Alva Solo is a dedicated phono stage for moving magnet cartridges. It amplifies the low-level turntable signal to a nominal 300 mV output, with 39 dB of gain at 1 kHz and RIAA equalisation accurate to +/- 0.65 dB from 30 Hz to 20 kHz. The input is 47k ohm with 100 pF capacitance, and the overload margin is above 30 dB.

The circuit uses a surface-mounted circuit board and a switch-mode power supply, both aimed at keeping noise and hum low. Signal to noise ratio is above 90 dB and THD+N is below 0.0025%. A subsonic filter removes low-frequency rumble from worn records, and a balance control corrects channel imbalance from a cartridge.

For power, the unit switches itself off after 20 minutes of inactivity and draws under half a watt in standby. It accepts mains voltages worldwide and ships with a mains lead. It is intended to sit between a turntable and an amplifier or hi-fi system that lacks a built-in phono input, or to replace a turntable's weaker internal preamp.