Audio Research producing a digital converter? This company -- analogue stalwarts enamoured with valves -- has resisted involvement with Things Digital until the moemnt in the format's history when digital earned, in ARC's own words, 'a degree of technological maturity that allows the introduction of products thatw ill provide years of cutting-edge performance without the threat of rapid (and costly) obsolescence'.

The phrasing implicitly covers a lot of territory, and reading between the lines produces the following: Audio Research, while far from a conservative company a la McIntosh or Quad, waited not until market penetration of CD was accomplished (that happened over three years ago) but until the sounds it could reproduce were of a true high-end standard. Among the refinements/developments which made this possible are stand-alone transports of exceptional quality, anti-jitter circuitry, better DACs, greater experience in the recording and manufacture of CDs, a superior optical connector to the dreaded TOSlink and any of a few dozen other developments which distance today's CD playing from the 14-bit disasters which heralded the format's coming some eight or nine years ago.

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So Audio Research has produced a stand-alone D/A converter, the #2940 DAC1. It's tubeless, but that's neither here nor there. My favourite product in ARC's catalogue is the SP-14, and that sports but one lone bottle. What makes this worth note is that it comes from a firm so absolutely au fait with the subtleties of analogue, and Wm Z Johnson is unlikely to allow the logo to appear on some typically digital doggie-do. The heart of the DAC1 is the superb UltraAnalog 18-bit, 8-times oversampling design, which seems to find a home in all the best devices.

What I love about D/A converters is that there's so little to describe. The DAC1 features only three toggle switches, two LEDs and input/output socketry, calling for minimal customer involvement. It doesn't even feature switchable sampling frequencies, preferring to make this function wholly automatic. So shove in your DAT recorder and forget about switches.

Across the front are an on/off switch with LED indicator (it glows dimply until the device settles down), a phase inversion switch which works in the digital domain and a switch to select one fo three inputs. Next to this is a green LED which tells you when the chosen input is receiving a locked-in digital signal.

The back features gold-plated output sockets and three sets of inputs. And it's here that we find the first points to ponder. All three accept coaxial leads, but via BNC plugs instead of phono (RCA-type) plugs because it's superior. Full Stop. But ARC supplies two phono-to-RCA adaptors so you can switch on immediately, just in case you're in ahurry and not in the mood to solder a BNC onto your favourite coaxial cable. This is restriction No. 1, but it's no hindrance unless you're so anti-adaptor that it makes you see red.

Then we get to the lone optical input. This is fitted to Input No 1; a small toggle switch between the optical an coaxial sockets lets you choose between the two. This also makes it very simple to A/B optical vs coaxial. But here's the rub: Because the TOSlink connector is so loathed bo so many, ARC has fitted an AT&T/ST-type optical connector. And, to the best of my knowledge, only Wadia and Barclay produce CD transports with this type of optical output. And I own neither.