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DACs — Pro-Ject DAC Box RS2
Description, images, technical data and specifications
Pro-Ject DAC Box RS2
Image source — © Pro-Ject
The DAC Box RS2 is a high-end standalone D/A converter made by Pro-Ject Audio Systems, derived from the Pre Box RS2 Digital with the analogue preamplifier section removed, so it has a fixed output level. The recommended retail price in Europe is EUR 1,699. It uses ESS Sabre converter chips in a dual mono configuration, carries a display with a responsive user interface, and its casework is offered in silver or black. An all-aluminium remote handset is included.
Key specs that matter
Two ESS9038Q2M chips, one per channel, accept PCM up to 32 bit and 768 kHz and DSD up to DSD512. The asynchronous USB input handles 32 bit and 768 kHz plus DSD as DoP or native. Of the six digital inputs, the remaining ones are a balanced AES/EBU socket, a single coaxial port and a pair of Toslink optical ports, all limited to 24 bit and 192 kHz, plus an I2S link over HDMI. MQA is supported with full hardware unfolding. Output impedance is 180 ohm in solid-state mode and 220 ohm in tube mode. THD+N across 20 Hz to 20 kHz is below 0.0008% in solid-state mode and 0.001% in tube mode, measured at 2 V RMS and 1 kHz. The case measures 206 x 72 x 222 mm and weighs 1520 g without the supply.
Engineering and use context
A fully balanced, double mono topology is used throughout. PCM and MQA material can optionally be upsampled with proprietary filtering, and re-clocking is performed by an XMOS chip with a multi-core RISC architecture. A switch selects either a tube circuit using four 6922EH valves or a solid-state circuit. In the maker's words the design is ultra-linear and extremely low in noise. Power comes from an external 20 V, 3 A DC supply rated for 110 to 240 V mains at 50 or 60 Hz, with a maximum draw of 1.2 A DC and standby use under 0.5 W. The product is listed as Roon Tested and works with Audirvana, and it also carries the Hi-Res Audio designation.
Pairing
The analogue pre-out is offered on both XLR and RCA sockets, letting the DAC connect to balanced as well as unbalanced amplifier inputs. The HDMI I2S input is intended for the CD Box RS2 T transport, and the DAC also provides a 16.9344 MHz master clock output to that transport, so the two units run from a shared clock. Computer playback runs over the asynchronous USB connection.
Alternatives
The DAC Box RS Final Edition from Pro-Ject uses two Texas Instruments PCM-1792 chips, a switchable Diamond ECC88 tube or Class A output, DSD128 over PCM and nine input options.
Key specs that matter
Two ESS9038Q2M chips, one per channel, accept PCM up to 32 bit and 768 kHz and DSD up to DSD512. The asynchronous USB input handles 32 bit and 768 kHz plus DSD as DoP or native. Of the six digital inputs, the remaining ones are a balanced AES/EBU socket, a single coaxial port and a pair of Toslink optical ports, all limited to 24 bit and 192 kHz, plus an I2S link over HDMI. MQA is supported with full hardware unfolding. Output impedance is 180 ohm in solid-state mode and 220 ohm in tube mode. THD+N across 20 Hz to 20 kHz is below 0.0008% in solid-state mode and 0.001% in tube mode, measured at 2 V RMS and 1 kHz. The case measures 206 x 72 x 222 mm and weighs 1520 g without the supply.
Engineering and use context
A fully balanced, double mono topology is used throughout. PCM and MQA material can optionally be upsampled with proprietary filtering, and re-clocking is performed by an XMOS chip with a multi-core RISC architecture. A switch selects either a tube circuit using four 6922EH valves or a solid-state circuit. In the maker's words the design is ultra-linear and extremely low in noise. Power comes from an external 20 V, 3 A DC supply rated for 110 to 240 V mains at 50 or 60 Hz, with a maximum draw of 1.2 A DC and standby use under 0.5 W. The product is listed as Roon Tested and works with Audirvana, and it also carries the Hi-Res Audio designation.
Pairing
The analogue pre-out is offered on both XLR and RCA sockets, letting the DAC connect to balanced as well as unbalanced amplifier inputs. The HDMI I2S input is intended for the CD Box RS2 T transport, and the DAC also provides a 16.9344 MHz master clock output to that transport, so the two units run from a shared clock. Computer playback runs over the asynchronous USB connection.
Alternatives
The DAC Box RS Final Edition from Pro-Ject uses two Texas Instruments PCM-1792 chips, a switchable Diamond ECC88 tube or Class A output, DSD128 over PCM and nine input options.
Specifications
Model name
DAC Box RS2
Conversion type
N/A
Engine
ESS9038Q2M
DSD compatability
Yes
Parameters
up to 32bit/768kHz and DSD512
Frequency response low +/- 3dB (Hz)
N/A
Frequency response high +/- 3dB (Hz)
N/A
Gain (dBu)
N/A
Output Level (balanced) (V)
N/A
Output Level (single-ended) (V)
N/A
Input Impedance (balanced) (Ω)
N/A
Input Impedance (single-ended) (Ω)
N/A
Output Impedance (balanced) (Ω)
180 solid state, 220 tube
Output Impedance (single-ended) (Ω)
180 solid state, 220 tube
Analog outputs
N/A
Signal to Noise Ratio (dB)
N/A
Total Harmonic Distortion + Noise (% at 22 kHz)
< 0.0008
Dimensions (mm)
206 x 72 x 222
Weight (kg)
1.52
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