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.

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.

At first, I was furious, wondering how ARC could fail to inclue a TOSlink as an option for the other 99.9999999% of the world's CD users. ARC, I must suppose, was merely sticking to its guns, refusing to compromise the performance of the DAC1 just for the sake of universality. In this respect, the company deserves the same recognition as Madrigal, who felt so strongly about optical connections that they made the proceed coaxial-only. And, like Wadia and Barclay, I must also nod to ARC for having the integrity to say, 'If you must use optical, then it has to be the vastly superior AT&T connection'.

This still ticked me off no end, as there are two other inputs, and it would have killed 'em to slip in a TOSlink for convenience's sake. So, through kindness on the part of Pedro at Acoustic Energy, I managed to borrow a Wadia transport, and I'm glad I did. This superb transport showed me something which may be a thought harboured by many at ARC: optical -- AT&T or otherwise -- still sucks.

As the Wadia WD3200 features coaxial and optical outputs, I wired both to the DAC1. I tried it with optical on Input 1 and coaxial on Input 2, and also with both wired to Input No1, selecting via the toggle. With myself and three volunteers doing the listening, on seven out of eight demonstrations the coaxial was preferred. But there was a reason.

The one test where the optical beat the coaxial happened when I was using what I thought was a pretty hot digital coaxial interconnect. Then I tried Siltech's new, dedicated-to-digital HF-6 silver wire. Expensive at #75 for 0.5m unterminated, right?

Wrong. Very wrong.

In every case where the Siltech was used, the improvement over the optical connection was so great that two wholly non-audiophilic types and a young 'golden ears' chose the coaxial consistently and repeatedly. From this point on, then, I'm referring to the DAC1 in coaxial mode and with the Siltech wire. And I'll tell you right now that you won't get the measure of the coaxial input on any stand-alone D/Q converter unless you audition it with HF-6. And when I try, however arbitrarily, to measure its value when compared to other accessories or tweaks, I can only come up with the conclusion that at #75 it's the CD fetishist's Bargain of the Year. But back to the DAC.

To learnwhat the DAC1 could do, I used it with the Krell MD2, the Wadia and the transport section of the Marantz CD-12And what we found was that the coaxial provided richer, fuller, more natural bass, greater front-to-back depth, a sweeter top end and a greater 'acoustic'. In only one area did the optical transmission show any superiority, and that was marginally deeper bass extension. And I do mean marginal. And what it gained in extension, the coaxial balanced with greater weight. and with the Siltech wire.

Ary -- however arbitrarily -- . Lead-swapping -- I only had one piece of the Siltech -- involved running each transport with the HF-6, Gryphon's new dedicated digital coaxial wire and Master Link Grey. What I found was this:

Discs played through the Audio Research DAC1, while lacking the 'ultra' analogueness of the CAL Tempest II SE (and, therefore, its highly euphonic inaccuracies...), suffers less from digital grain, edge or sharpness than any other combination I can name, while still retaining all of the detail in the recording. This is not a case of shaving off bits here and there, nor of acting like some kind of trick filter. The DAC1 merely reassembled the digital jigsaw puzzle with fewer visible cuts, the pieces blending together with a seamlessness which suggests some sort of sonic Moulinex. The various and disparate parts flowed into a concrete, cohesive whole. No Viewmaster 3D, no pockets of mono here and there, no more Frankestein's monster.

Part of the magic is the phase inversion facility, which showed the importance of phase integrity more vividly than any other device I've yet encountered. So profound is the change wrought by the use of the switch, that one must flick it to-and-fro during an audtion to make certain that it's in the right mode. Invert when it should be straight through, or vice versa, and the DAC1 will sound no better than a #149 Dixon's Special.

As it stands, the DAC1 goes straight in as my reference converter, regardless of transport but most definitely with the Siltech HF-6 in the chain. Whatever your feelings about CD, you owe it to yourself to hear your favourite torture track through this device. It is, quite simply, the best thing to happen to CD since the advent of the mid-price disc.

The phrasing deep marketars ago) but until the sounds CDers which is typically digital doggie-do. Hence t (And forget about a digital-out signal, too...)fromBNC is by virtue of offering a constant 75-oum impedancea deither/orthe twoonly ype of optical output. And I havednot that 1 and coaxial on Input 2 and helping with the listeningButinserted ,viany other combination I can name-style It makes CD musical, from top to bottom, by restoring and/or extracting a finer sense of ambience, of texture and of warmth than was previously available. Its midband is so lifelike that it should be issued with free copies of

Remembering Big Bill Broonzy.