Review: Pro-Ject Pre Box RS Digital – Chameleon

Technical data

Pro-Ject Pre Box RS Digital


DAC1 – 2 x PCM1792 24/192

DAC2 – PCM5102 32/384


6922 EH

Digital inputs

1 x USB 2.0 Audio 32/384 + DoP-DSD 64/128

1 x RJ45 Sonic I2S for CD Box RS in Sonic Mode

2 x S/PDIF 24/192, 4 x S/PDIF Optical 24/96

1x AES/EBU balanced 24/192

Line-level input

1 RCA/phono sockets

Input impedance


Analog outputs

Pre-out (XLR & RCA), Headphone (6,35mm jack)

Headphone impedance

5 / 20 / 50 ohms switchable

Analog input sensitivity

1,6V RMS for full headphone output

Frequency response

20Hz – 50kHz (+ 0/- 0,1 dB)

Signal to noise ratio

-100dB (IEC-A)


0,005% solid state output/ 0,25% tube output

Master clock output

16,9344MHz for CD Box RS in Sonic Mode

Outboard power supply

20V/3A DC

suitable for your country’s mains supply

Power consumption

300mA solid / 850mA tube / 90mA standby

Dimensions W x H x D

206 x 72 x 200mm (210 with sockets)


1950g without power supply

Sound and more after the jump:



Back before he became the main photographer for bunches of audio magazines and stuff, Nathan was fiddling with pretty cool audio gear all day long at TouchMyApps. He loves Depeche Mode, trance, colonial hip-hop, and raisins. Sometimes, he gets to listening. Sometimes, he gets to shooting. Usually he's got a smile on his face. Always, he's got a whisky in his prehensile grip.


  • Reply June 23, 2016

    Barun C

    Nice review Nathan. I’ve very much similar thoughts about companies who specialise in DACs and get into making DAC amps but have problems with implementing a good amp stage, with the exceptions being the Resonessence Labs Concero HP and the low impedance amp section of the Audiotrak Dr. Dac 2 DX.

  • Reply June 23, 2016


    Can I choose between solid state and tube output for the headphone jack? or just for the pre out balanced / unbalanced?

    • Reply June 23, 2016

      ohm image

      You can choose between valve or solid state for both.

  • Reply September 19, 2016

    Michel INGELS

    Hello Nathan,

    Thank you for this nice review. You ended it by “NOTE: Pro-Ject are looking into the headphone performance of the unit loaned me.”

    Did you receive any further reaction about it from Pro-Ject?

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