Фонокорректоры — Pro-Ject Phono Box RS2

The Phono Box RS2 is a balanced phono stage, and Pro-Ject Audio Systems places it in its reference class. It handles both MM and MC pickups, keeps the signal balanced all the way through, and is built from discrete transistors without any operational amplifiers in the signal path, in a true dual mono layout. Silver and black versions are made.

Key specs that matter

Two input types are fitted - one balanced XLR pair and one single-ended RCA pair - and the outputs are offered on both XLR and RCA as well. Moving magnet gain can be set to 40, 43, 46 or 50 dB via the RCA outputs, while the MC positions give 60, 63, 66 or 70 dB, and the XLR outputs add 6 dB to every figure. Loading is a fixed 47 kohm or a continuously variable 10 to 1,000 ohm, with capacitance selectable in eight steps from 50 to 400 pF. Rated signal to noise is 89 dB A-weighted for MM at 40 dB with 10 mV input and 79 dB for MC at 60 dB with 1 mV. THD at 1 kHz is under 0.0015 percent for MM and under 0.0024 percent for MC. RIAA accuracy stays within 0.4 dB from 20 Hz to 20 kHz, and a subsonic filter works at 20 Hz with an 18 dB per octave slope. The supplied 20 V, 3 A DC adapter accepts 110 to 240 V mains, and the unit draws 350 mA and less than 1 W in standby. It measures 206 x 72 x 200 mm with sockets and weighs 1.6 kg without the adapter.

Engineering and use context

In a true balanced amplifier the plus and minus halves of each channel have their own circuit, so the RS2 carries four amplifier sections, and noise picked up equally on both legs of the signal is subtracted out. Equalisation is split and passive, and a selector offers the DECCA curve next to RIAA. Pro-Ject's potentiometer loading system lets the owner turn the impedance during playback and hear the effect at once. A second control shifts the channel balance by up to 2 dB left or right to compensate for small level differences between the two cartridge coils. The chassis is steel covered with screwed aluminium panels for rigidity and screening. An outboard linear supply, the Power Box RS2 Phono, is offered as an upgrade in a case the size of the preamplifier.

Pairing

The highest gain settings suit MC pickups with very small output, while the XLR input suits turntables wired for balanced transfer. The XLR outputs are the natural match for a balanced preamplifier or integrated amplifier.

Alternatives

The Pro-Ject Phono Box DS3 B belongs to the DS3 line and likewise relies on fully discrete, balanced circuitry with stepless load matching and memory for two turntables.