A dual mono, balanced D/A converter with two ESS9038Q2M chips, six digital inputs and an output stage switchable between valves and solid state: PCM to 32 bit / 768 kHz, DSD512 and MQA.
DAC Box RS2: conversion and output stage
The DAC Box RS2 derives from the Pre Box RS2 Digital, minus its analogue preamplifier section: what remains is a pure converter with a fixed-level output. The two ESS9038Q2M chips work one per channel, with separate signal paths for left and right on a fully balanced circuit. Over USB it accepts PCM as high as 32 bit / 768 kHz and DSD up to DSD512, DoP included; the other inputs go up to 24 bit / 192 kHz.
The USB input is managed by a multi-core XMOS microcontroller, while re-clocking is entrusted to an Altera MAX II CPLD. MQA decoding is complete and done in hardware. There are eight selectable digital filters, among them the optimal-transient filter devised by the creators of MQA, and they allow the sound to be tuned to personal taste. The output stage, discrete and balanced, switches between solid state and 6922 valves: the choice is left to the listener.
Besides USB, two optical, one coaxial and one AES/EBU input there is an I2S input on an HDMI connector intended for the CD Box RS2 T transport, to which the DAC also supplies the 16.9344 MHz master clock. Analogue outputs are XLR and RCA. The large front display sets out the information in an orderly way and the menu responds quickly; an aluminium remote control is supplied.
Specifications
- D/A converters: 2 x ESS9038Q2M in dual mono configuration
- Maximum resolution over USB: PCM 32 bit / 768 kHz, DSD512 native and DoP
- Digital inputs: USB 2.0, HDMI I2S, balanced AES/EBU, coaxial, 2 optical
- Optical, coaxial and AES/EBU inputs: up to 24 bit / 192 kHz
- MQA: complete hardware decoding
- Analogue outputs: XLR and RCA
- Output impedance: 180 ohms solid state, 220 ohms valve
- Distortion (THD+N): under 0.0008% solid state, 0.001% valve (2 V RMS, 1 kHz)
- Output stage: discrete and balanced, valve or solid state
- Valves: 4 x 6922EH
- Master clock: 16.9344 MHz output for the CD Box RS2 T transport
- Power: 20 V / 3 A DC from a 110-240 V mains adapter
- Current draw: 1.2 A maximum; standby under 0.5 W
- Dimensions: 206 x 72 x 222 mm (width, height, depth), sockets included
- Weight: 1520 g, power supply excluded
- Finishes: black, silver
