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 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 is 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 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 an incredibly powerful tool for high-end 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. True Balanced Connections The interconnect cable between a record player and a phono stage is prone to pick up noise on the way. That noise and interference can stem from a lot of unavoidable sources, such as household applicances, wi-fi and bluetooth devices, other power cables and audio amplifiers. Unshielded (i.e. RCA) interconnects can amplify the picked-up noise and make it audible through your speakers, interfering with the pure musical signal. Balanced (typically XLR) cable connections double the wires carrying the musical signal – with one side inverted. In this case noise still gets picked up by both wires, but with one side reversed. When the signals are re-joined at the phono stage, the picked-up noise is cancelled out by the opposing signals. The benefit of this is a louder, cleaner musical signal that has doubled in size with almost no remaining noise. Click here to read more about ‘True Balanced Connections’ . Key Features: High class, affordable phono stage MM & MC capable Sturdy metal casing protects against vibration and interferance Fully discrete hardware design – No op- amps Fully passive RIAA & DECCA equalisation Balanced XLR & Unbalanced RCA inputs & outputs. Unique continuously variable input impedance loading and channel ballance controll to match every cartridge to %100 (adjustment even while playing) super low noise and low distortion. Available in silver or black Specs Input Impedance: Fixed 47kohms, Variable 10-1000 ohms Gain: MM: RCA 40, 43, 46, 50dB (+6dB using XLR) MC: RCA: 60, 63, 66, 70 dB (+6dB using XLR) Signal To Noise Ratio: MM: (40dB): 89dB A-wt (10mV; < 0,0024% (MC60dB, 1kHz) Input Impedance: Fixed 47kohms, variable 10 - 1000 ohms Load capacity switchable: 50, 100, 150, 200, 250, 300, 350, 400 pF THD: < 0,0015% (MM 40dB, 1kHz); < 0,0024% (MC 60dB, 1kHz) Input impedance: Fixed 47kohms, variable 10 - 1000 ohms RIAA Accuracy: within 0,4dB/20Hz - 20kHz Inputs: RCA & XLR Outputs: RCA & XLR Subsonic at: 20Hz with 18dB/octave Outboard Power Supply: 20V/3A DC; 110 - 240V, 50/60Hz PSU: 20V / 3A DC Dimensions W x H x D (D with sockets): 206 x 72 x 200 (230)mm Weight: 1600g without power supply Power Consumption: max 350mA DC Hi-Fi Choice, October 2021 Verdict: 5/5 Comments of Note: "Superbly refined and accurate sonics; features; solid build. A reference level phono stage that offers an exceptional level of performance and very flexible spec." Read the full article here.
