Pro-Ject Audio Systems has announced a new flagship phono stage to complement their extensive range of high-end turntables and electronics. The Phono Box RS2 is a fully balanced, fully discrete phono pre-amplifier of the highest quality, with extensive setting options to accommodate any turntable or cartridge system.

Available in either a Black or Silver metal chassis, the Phono Box RS2 is one of the most versatile and adjustable devices in todays market.

Phono Box RS2 Features Include:
✓ Full moving magnet (MM) and moving coil (MC) suppor
✓ Fully balanced, true dual mono electrical design
✓ Fully discrete hardware design, utilising no op-amps
✓ Fully passive, selectable RIAA and DECCA equalisation curves
✓ Balanced XLR and unbalanced RCA inputs and outputs
✓ Continuously adjustable impedance dial for MC cartridges (adjustable during playback)
✓ Adjustable Gain and Capacitance settings
✓ Channel balance control to suit any cartridge (adjustable during playback)
✓ Subsonic filter switch
✓ Superior low noise and low distortion measurements
✓ Steel and aluminium casing to protect against vibration and interference
Phono Box RS2: £1,299.00 (SRP)
Available in Black or Silver finish from January 2021.

Phono Box RS2 in detail

The Phono Box RS2 sets out to be the ultimate phono preamplifier, in the highest class. It is a fully discrete, fully balanced dual-mono device with split passive RIAA and DECCA equalisation, resulting in a “no expense spared” phono stage designed to achieve the best possible sound. It is also extensively adjustable, suiting it to any system, environment or personal listening taste.

After countless hours of listening tests and many years of experience, the Pro-Ject design team took the decision to employ discrete circuitry in the Phono Box RS2. Discrete circuits involve no operational amplifiers (op-amps) and the end result is a more neutral, natural, dynamic and vivid sound. They are more complicated to put together and involve a greater variety of components, but the result when utilised in a well-organised electrical layout is a true high-end sound.

Elsewhere the Phono Box RS2 circuitry is fully balanced throughout, meaning the + and – signal chains are treated individually for absolute signal integrity, resulting in less unwanted noise, errors and interferences. It’s because of this layout that the phono stage measures so well in its signal-to-noise ratio.

The Phono Box RS2 uses split passive equalisation for both its RIAA and DECCA curves. This is more costly to design and implement, but ensures the most accurate representation of the ideal EQ curve, and allows for better impedance matching.

Similar attention to detail is employed throughout the cartridge matching options. The Phono Box RS2 has eight optional settings for Gain, ranging from 40dB to 70dB. As 70dB gain involves a voltage amplification of many times the original cartridge signal, the quality of the electrical circuitry is paramount and needs to be incredibly silent – hence the other electrical design choices made. However, this range of choice makes for easier system set-up, allowing you to match the turntable output to other sources connected to your amplifier.

Load impedance can be manually adjusted via one of the two front-mounted potentiometers. This innovative system allows for seamless adjustment of the impedance during playback, anywhere from 10 to 1,000Ω, allowing you to find the perfect load impedance for your cartridge. Elsewhere there are also eight different options for capacitance – allowing for better cartridge matching with MM systems.

A final innovation for the Phono Box RS2 is the introduction of a balance function. Pick-up cartridges, by their nature, suffer from small imbalances between the left and right channels. To correct this, the Phono Box RS2 features a second potentiometer on the front panel to adjust the exact centre of the sound stage, ranging from 2dB to the right or left. This range of tolerance covers almost all good cartridges, and truly means the Phono Box RS2 is one of the most versatile phono stages on the market.

To maintain signal integrity, the Phono Box RS2 is supplied with an external 20V power supply. During 2021 Pro-Ject Audio Systems will also introduce a true high-end linear power supply upgrade that will work with the Phono Box RS2. The Power Box RS2 Phono will feature a purpose-designed transformer and circuitry in order to deliver a clean and stable 20V signal to the Phono Box RS2, and will also feature an extra 15V output for direct connection to a supported Pro-Ject turntable.

The Phono Box RS2 is a tool for enthusiasts and professionals who are looking to ‘perfectly match their turntable and cartridge to the rest of their system’. However, despite its many available features, because its core focus is on absolute signal integrity and a class-leading electrical design, it will also suit users who simply expect the best sound possible from their vinyl hi-fi system. Purists can effortlessly enjoy the best sound while experts and tech-enthusiasts will find their perfect high-tech phono stage – the Phono Box RS2 truly is ‘the ultimate solution’.

Technical Information
Input Impedance: Fixed: 47kΩ
Variable: 10 – 1,000Ω
Load Capacitance: Switchable: 50, 100, 150, 200, 250, 300, 350 or 400pF
Gain: MM (RCA): 40, 43, 46 or 50 dB (+6dB using XLR)
MC (RCA): 60, 63, 66 or 70 dB (+6dB using XLR)
Signal to Noise Ratio: MM (40dB): 89dB A-weighted (10mV)
MC (60dB): 79dB A-weighted (1mV)
THD: MM (40dB, 1kHz): < 0.0015%
MC (60dB, 1kHz): < 0.0024%
RIAA Accuracy: Within 0.4dB / 20Hz – 20kHz
Subsonic Filter: At 20Hz with 18dB/octave
Inputs: 1 x RCA (pair) / 1 x XLR (pair)
Outputs: 1 x RCA (pair) / 1 x XLR (pair)
Power Supply: 20V / 3A DC
Power Consumption: Max. 350mA DC
Dimensions (W x H x D): 206 x 72 x 230mm (including sockets)
Weight: 1,600g (excluding power supply)

No more articles
%d bloggers like this: