Pro-Ject Phono Box RS2 Phono Preamplifier
The Phono Box RS2 is the ultimate phono preamplifier. Fully balanced from input to output, the electronics are fully discrete, the unit is free of op-amps, and it uses split passive RIAA or DECCA equalization.
A discrete circuit is composed of electronic components that are separate, individual devices – also called 'discrete' components. These are 'passive'"' components (like resistors, capacitors and inductors) as well as 'active' ones, in this case transistors.
The opposite of this would be an integrated circuit with operational amplifiers (op-amps) in the signal chain. Countless hours worth of listening tests and years of experience have shown us that even the very best op-amps do not tend to be neutral, natural, dynamic nor vivid.
Standard phono pre-amplifiers with integrated circuits have tens or hundreds of components, but discrete designs employ hundreds or thousands of components by comparison. That makes for an extended and more costly design process, but results in the best sound for your money.
Phono Box RS2 employs a true fully balanced design principle. Balanced transmissions consist of a hot and a cold (also called + and -) signal. Both the + and – signal chains effectively carry the same musical information. A true balanced amplifier can now extract the final musical information out the +/- signals and subtract (remove) all noise that could potentially be added along the transmission.
In a true, fully balanced amplifier like Phono Box RS2, the + and – sections of both the left and right channels are treated individually, which doubles the amplifier sections as a result.
Split Passive EQ
Phono Box RS2 uses split passive equalization 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. Split passive equalization allows for better impedance matching and lower deviation from the ideal RIAA or DECCA curve.
Numerous Cartridge Loading Options
No other phono preamp in the world offers the gain flexibility of Phono Box RS2. A huge range from 40dB (voltage amplification by 100x) up to 70dB (voltage amplification by 3690x) is possible. Load impedance can be set on the fly via a potentiometer – a system invented by Pro-Ject Audio Systems.
It allows you to seamlessly adjust impedance during playback and immediately assess the impact of various loading options. By nature, cartridges suffer from small imbalances between the left and right channels. To correct this, Phono Box RS2 introduces a new feature that is rare in this price category.
A potentiometer allows you to adjust to the exact center of the sound stage in a range of 2dB to the left or right.
The Phono Box RS2 has a steel chassis that is covered by aluminum panels. This construction delivers great rigidity and splendid isolation from interference.
Input impedance: Fixed 47kohms, variable 10 - 1000 ohms
Load capacity switchable: 50, 100, 150, 200, 250, 300, 350, 400 pF
MM: 40, 43, 46, 50 dB (+6dB using XLR)
MC: 60, 63, 66, 70 dB (+6dB using XLR)
Signal to noise ratio:
MM (40dB): 89dB A-wt (10mV)
MC (60dB): 79dB A-wt (1mV)
< 0,0015% (MM 40dB, 1kHz)
< 0,0024% (MC 60dB, 1kHz)
RIAA accuracy: within 0,4dB/20Hz - 20kHz
SubsonIc: at 20Hz with 18dB/octave
Inputs: RCA & XLR
Outputs: RCA & XLR
Power supply: 20V/3A DC; 110 - 240V, 50/60Hz
Power consumption: 350mA DC < 1 watt standby
Dimensions (WHD): 8.1" x 2.8" x 7.9"
Weight: 3.5 lbs.