Phono preamplifier for MM and MC cartridges
The Cambridge Audio Alva Duo is a separate phono stage that accepts both moving magnet (MM) and moving coil (MC) cartridges: flexibility that makes it compatible with a wide range of turntables. It raises the cartridge's tiny signal to line level, 300 mV nominal, with a gain of 39 dB for MM and 60 dB for MC.
Input impedance is 47 kohms for MM and 100 ohms for MC, with an input capacitance of 100 pF; the RIAA curve is followed within ±0.3 dB from 30 Hz to 20 kHz.
Built-in headphone amplifier
The Alva Duo has a headphone amplifier with a 6.35 mm output on the front panel: it allows records to be enjoyed privately, even late at night, without switching on the rest of the system. Just connect the turntable and the headphones.
The subsonic filter removes the very low frequencies produced by worn records, for a cleaner sound.
A low-noise design
The switch-mode power supply operates outside the audible frequencies, so it introduces neither hum nor interference, and the surface-mounted circuit keeps the signal as clean as possible. The stated signal-to-noise ratio exceeds 90 dB with MM and 70 dB with MC; THD+N at 1 kHz is below 0.0025% (MM) and 0.20% (MC), with an overload margin above 30 dB.
After 20 minutes of inactivity the unit switches itself off; in standby it draws less than 0.5 W, at most 10 W in use, and it accepts mains voltages worldwide.
Dimensions and accessories
The Alva Duo is grey, measures 48 x 215 x 159 mm (height, width, depth) and weighs 0.95 kg: at 215 mm wide it takes up half the space of a traditional hi-fi component.
The box contains the mains lead, the user manual and the safety guide.
