Pro-Ject Tube Box DS3 B True Balanced Phono Preamplifier - Black - Ex Demo

Product Details

• Brand: Pro-Ject
• Model: Tube Box DS3 B
• Finish: Black

Condition Notes

This Pro-Ject Tube Box DS3 B came off our own demonstration floor and is in excellent condition. The black fascia is clean with no notable marks, the loading potentiometer and selector buttons operate correctly, and the valve cages and rear sockets are unmarked. It is supplied with its original E88CC valve pair, the external power supply and the documentation, in the original carton. One only, at a saving over the $1,529 RRP.

The DS3 B is the Tube Box the rest of the range has been building towards. Pro-Ject has made valve phono stages for years, but this is the first to run genuinely balanced from input to output, with a 5-pin mini XLR and a full XLR pair alongside the usual RCA, and a balanced XLR output at the other end.

That matters more for phono than for anything else in a system. A cartridge produces a few millivolts, and it is inherently a balanced source, so running it balanced rather than converting to single-ended at the tonearm keeps common-mode noise out of the quietest signal in the chain. If your preamplifier has balanced inputs, this is where the benefit actually shows.

The loading arrangement is Pro-Ject's own and remains unusual: impedance is set by a continuous potentiometer rather than fixed steps, so you can turn it while a record plays and hear the cartridge respond in real time rather than guessing between presets. Gain runs from 40 dB to 65 dB, capacitance from 50 to 400 pF, and two turntables can stay connected at once.

Amplification is by two E88CC valves with polypropylene capacitors throughout, and there is an 18 dB per octave subsonic filter at 20 Hz for warped records. For a serious cartridge on a serious arm, it is a long way past what a solid-state stage at this money will tell you.

Main Specifications

• Configuration: Valve phono stage for MM and MC, true balanced in and out
• Valves: 2 × E88CC / 6922
• Gain: 40 / 45 / 50 / 55 / 60 / 65 dB (+6 dB using the XLR output)
• Input Impedance: Stepless 10 – 1,000 Ω, or fixed 47 kΩ
• Capacitance: 50 / 150 / 300 / 400 pF
• Output Voltage: 500 mV at 1 kHz from 5 mV input (at 40 dB)
• Signal to Noise Ratio: Greater than 87 dBV, A weighted
• Total Harmonic Distortion: Less than 0.03%
• RIAA Accuracy: ±0.5 dB, 20 Hz – 20 kHz
• Subsonic Filter: 20 Hz at 18 dB per octave
• Inputs: 1 × 5-pin mini XLR, 1 × XLR pair, 1 × RCA pair
• Outputs: 1 × XLR pair, 1 × RCA pair
• Power Supply: External 18 V / 1,000 mA DC
• In the Box: External power supply, documentation, original carton
• Dimensions (W×H×D): 206 × 70 × 194 mm
• Weight: 1.56 kg without power supply