The Phono Box is a phono preamplifier for MM and MC cartridges, with a selector on the rear panel and a line-level output: it links a turntable to an amplifier that has no phono input.
Phono Box: what it does and how it connects
Many of today's amplifiers no longer carry an input for a turntable cartridge. The Phono Box fills the gap: it amplifies the turntable signal, equalises it to the RIAA curve and delivers it to an ordinary line input such as AUX. A switch at the back chooses between MM, with 40 dB of gain and a 47 kohm load, and MC, with 60 dB and 100 ohms; input capacitance is 120 pF either way.
The circuit uses low-noise integrated circuits and an output stage of very low impedance, which reaches 9.5 V at 1 kHz. RIAA equalisation stays within 0.5 dB from 20 Hz to 20 kHz. The stated noise figures are 94 dBA for MM and 75 dBA for MC, with distortion of 0.01 % and 0.05 %. With a 3 mV MM, or a 0.3 mV MC, typical output is 300 mV.
The RCA sockets are gold-plated and the small footprint lets it sit beside the turntable, so the cable carrying the cartridge signal stays short. Power is supplied by an external 18 V DC adaptor, and on standby consumption is below 1 W. The faceplate is offered in more than one finish.
Specifications
- Type: MM/MC phono preamplifier with line output
- MM/MC selection: switch at the back
- MM input impedance: 47 kohms / 120 pF
- MC input impedance: 100 ohms / 120 pF
- Gain: 40 dB (MM), 60 dB (MC)
- Typical output: 300 mV at 1 kHz from 3 mV (MM) or 0.3 mV (MC) in
- Maximum output: 9.5 V at 1 kHz
- Noise: 94 dBA (MM), 75 dBA (MC)
- Harmonic distortion: 0.01 % (MM), 0.05 % (MC)
- RIAA accuracy: within 0.5 dB from 20 Hz to 20 kHz
- Sockets: gold-plated RCA
- External power supply: 18 V DC, 200 mA
- Standby consumption: under 1 W
- Weight: 570 g
- Size (width x height x depth): 103 x 36 x 104 mm (115 mm over the sockets)
- Finishes: black, silver
