Pro-Ject Phono Box MM

The Phono Box MM is a phono preamplifier for moving-magnet cartridges and high-output moving coils: 40 dB of gain, RIAA equalisation and a line output for connecting a turntable to an amplifier with no phono input.

Phono Box MM: the essentials for a turntable

This is the entry phono stage in the range, intended for anyone whose amplifier lacks a turntable socket. It takes the signal from a moving-magnet cartridge, or from a high-output moving coil, equalises it to the RIAA curve and amplifies it by 40 dB so that it can go to a line input such as AUX. The input presents 47 kohms and 120 pF.

The circuit is dual mono, to keep the two channels well apart, and uses special low-noise integrated circuits: the stated figures are 88 dB A-weighted for noise and distortion under 0.04 %. With 5 mV in at 1 kHz the output is 500 mV. Both sets of RCA sockets are gold-plated.

The metal case screens the electronics from vibration and electromagnetic disturbance, and the external 18 V DC supply keeps the transformer away from the circuits. Its very modest size lets it be placed close to the turntable. Current draw is 20 mA and standby consumption stays under 1 W.

Specifications

• Type: phono preamplifier for moving magnets and high-output moving coils
• Input impedance: 47 kohms / 120 pF
• Voltage gain: 40 dB
• Output level: 500 mV at 1 kHz from 5 mV in
• Noise: 88 dB (A-weighted)
• Harmonic distortion: under 0.04 %
• Input: one pair of gold-plated RCA sockets
• Line output: one pair of gold-plated RCA sockets
• External power supply: 18 V DC, 500 mA
• Current draw: 20 mA DC, under 1 W on standby
• Weight: 280 g, power supply excluded
• Size (width x height x depth): 107 x 30 x 75 mm