In all honesty, most domestic DACs fall somewhere between ‘inadequate’ and ‘woefully inadequate’ when it comes to telling the world what they are doing. There are exceptions of course – Chord Electronics and its colour-coded control surfaces being an obvious example – but many domestic digital devices limit their interfaces to a few small LEDs denoting frequency, lock, occasionally your choice of source, and power. Sometimes, there’s not even a button to be found. The German brand RME comes from the pro-audio world. They do things differently there, and the ADI-2 series – including the ADI-2 DAC tested here – positively bristle with displays and control surfaces.
This is not the only aspect of professional audio that filters across to the general public. First, display aside, the product is that combination of solidly built and no-nonsense in approach; the power supply is an external box, and the case is solid, but not made from solid unobtanium covered in dodo leather and panda eyelids. The rear connectors aren’t cast from the purest copper known to man by dwarf-lords. And, unlike many domestic audio brands, the obsession with brand names on the circuit board is not as important as how it performs in its job. You won’t find RME crowing about using the latest chipset from the DAC brand du jour, just an impressive set of provided specifications and measurements.
The ADI-2 DAC’s no-nonsense approach extends to its inputs and outputs. It lacks some of digital audio’s alphabet soup, eschewing inputs such as AES/EBU, BNC, HDMI, I2S, RS232, and RJ45. Instead, it covers the basics with a lone USB 2.0 Type B, RCA coaxial and Toslink optical S/PDIF connectors (AES/EBU is supported if you use an adaptor on the coaxial input). For analogue, it features both single-ended RCA and balanced XLR stereo connectors, and two headphone sockets; a 3.5mm TRS minijack socket for in-ear designs, and a 6.3mm TRS jack socket for headphones. These are not ‘commoned’, but in fact reach back to two separate headphone amplifiers – a lower-gain, lower-noise design for extremely sensitive earphones and in-ear monitors, and a higher-output design for driving traditional headphones.
Then, we get to the nitty-gritty: the control surfaces. Using four push-buttons, three rotary/push knobs, and a small but colourful front-panel display. These are designed to set-up, and operate the DAC, and work in harmony with the black ABS shield-shaped remote. If you begin to wonder why a DAC needs this degree of user interaction, a quick flip through the comprehensive English/German manual quickly demonstrates the thoroughness of the RME concept. You can assign names to inputs and set the preamp to deliver different output levels for the line outputs and/or the ‘Hi-Power’ headphone output (the IEM output remains at a fixed reference -3dBu level), reference input levels. mono/stereo options, the choice of four digital filters, the ability to assign the centre dial to act as a volume or balance control, and controls for adjusting stage width, crossfeed, parametric EQ, tone, and de-emphasis.