Outboard DACs

A new arrival from the US with superb measured performance.

Bricasti’s M1 DAC invites comparison with the dCS Debussy [HFN Dec ’10]. Not merely because of its price and professional antecedents but because of a sterling performance on the test bench.

Not unnecessarily large, it oozes the solidity you’d expect of a proper professional audio product – it’s constructed of aluminium alloy panels machined from solid before being anodised and the markings laser-etched. This high standard is carried through to the circuit design: a double mono configuration with separate linear power supplies and DAC boards per channel. One thing we’d criticise is the inclusion of large ventilation slots in the top cover.

Each channel uses a single stereo Analog Devices 1955 high performance multi-bit delta sigma DAC chip, configured to operate in mono. Its on-board digital volume control is not used, while the filter pass-through mode allows Bricasti to apply its own, user-selectable reconstruction filters. Direct digital synthesis (DDS) clocking ensures extremely low levels of clock jitter to be achieved; synchronisation of the DDS clocks on each DAC board is accomplished by a Sharc DSP chip on the main digital processing board. Rather than fibreglass, the DAC boards are made from Arlon, a ceramic-filled PTFE on a lightweight fibreglass reinforcement.

Not a volume control, the circular knob that dominates the fascia is a jog control that allows you to scroll through the various set-up options, eg, AES/EBU, S/ PDIF (both balanced/unbalanced) or Toslink input, or the seven reconstruction filters. The input display shows the current sampling rate (up to 192kHz).

THE RIGHT BALANCE,
Although differences were small, we preferred the S/PDIF connection as marginally more revealing. And of the – too many? – filter options we quickly chose filter 1, regardless of sampling rate. With Eva Cassidy’s Simply Eva the dynamic range is a little squashed and there’s more EQ and reverb on her voice than we care for, but this is probably the minimumintrusion means of enjoying this fine singer. We used ‘Songbird’ (what else?) as one of the tracks for the 44.1kHz filter comparison, and it proved very revealing of the changes, large and small, that the different filter algorithms make to the M1’s sound. Filter 1 delivered just the right balance of warmth and intimate insight into the subtleties of that remarkable vocal tract.

Harrison Birtwistle’s Chronometer – a taped piece of electronic music released on DualDisc [SAM 0801] – is at the boundary of what many people would choose to call ‘music’ at all. It comprises numerous processed sounds recorded from different timepieces and was composed for quadraphonic replay.

Even in two-channel guise it’s a strangely compelling piece that creates, perhaps, a brooding undercurrent of dystopian dread. The M1’s ability to render vividly the diverse colours of all the elements of Birtwistle’s construction, and sustain that unsettling atmosphere throughout, went a long way to breathing life into what, on a lesser source, would weave its magic much less effectively.

We also tried HDtracks’ 24- bit/176.4kHz download of The Rolling Stones’ Through The Past Darkly, albeit downsampled to 88.2kHz because the TC Electronic box used to feed the S/PDIF signal to the M1 is only compatible with two-wire connection above 96kHz, a mode that the M1 doesn’t support. No matter, because there’s nothing but noise above 44.1kHz in these transfers in any case. Lacking KK’s extensive collection of successive releases of this material, Nonetheless we were utterly convinced that this is what those old analogue masters must really sound like. Rough and ready, brash, seething with testosterone…

VERDICT
However you look at it – sound quality, construction, engineering, test bench performance – the M1 hits the spot. All it lacks compared, say, to the dCS Debussy is an asynchronous USB input, which is a shame, otherwise it’s clearly in the same league. Cheaper too.

Originally published in the Yearbook 2011