The Unison Research Unico CDE CD player is the latest addition to the company's high-end components and was first introduced in Italy in April 2008.

Arriving in the UK slightly later, it has reportedly, and deservedly, established itself as a strong seller, thanks in part to its sonic performance, cutting-edge componentry and exceptional build quality.

The Unico CDE was developed from the earlier £1,495 Unico CD, but now has a larger chassis and an improved TEAC CD5010A transport mechanism. In its current configuration it utilises a new four-valve output stage using ECC83s (12AX7) in a double triode parallel cathode follower configuration.

Upgradable system

In other respects, this is a typically idiosyncratic offering from Unison Research, which is upgradable and includes the ability to accept internal DAC modifications on a small PC board that can be readily fitted once the top cover has been unzipped.

The Unison factory also supplied the DAC upgrade for this test, a very reasonably priced unit, which co-exists piggy-back fashion with the original equipment DAC. The latter is a crystal cS4392 unit which operates at 24 bit/96khz, either of which can be selected using a front panel menu.

The upgrade DAC_OP2 (option) board is a simple auto-configuring plug-and-play board which uses the same crystal CS8420 receiver as the standard converter, but whose main active component is the well regarded Wolfson Micro WM8740, used here as a dual- mono, dual-differential design.

That's the plus side, but there is another view. It may seem unfair to criticise any player such as this for not being what it was never intended to be, but it is regrettable that the Unico doesn't cater for SACD. After all, experience shows that SACD can be included on players without noticeable detriment to CD replay performance.

Comprehensive connectivity

The back panel repays examination. There are two main pairs of analogue outputs, one single-ended, the other balanced on XLR connectors. There is also a low and a high output gain switch, the latter adding 9dB of voltage gain using a solid-state opamp at the DA output, ahead of the valve output stage.

In addition there is a digital interface, an electrical SPDIF in/ output which can be fed to an offboard D/A. There is also a matching SPDI digital input, so the player can be used as D/A for an external digital source.

For the first 30 seconds after power up, the output is muted, with a countdown timer displayed on the large, but rather low contrast LCD front panel display (its backlighting adapts to ambient light conditions).

After this, performance continues to improve for the first ten minutes according to the manufacturer; though you may notice some further improvement for at least the first hour, until the player reaches thermal equilibrium.

Superb build quality

A so-called advanced menu option is available to select the required DAC and for related housekeeping tasks – to reset the DAC or the whole player, for example, for troubleshooting and to switch off the display.

After this, the unit responds to a conventional set of controls on the front panel, or using the elaborately crafted remote control, the only slight oddity being that there is no programme play option, though the traditional scan, skip and repeat options are on tap.

Build quality is excellent. The case uses black finished panels and a well-engineered matt aluminium fascia. The internal layout is clean, with a minimum of cable runs and a well-endowed power supply.

Easy-sounding player

We're not always enamoured of the sound of overtly valve-flavoured audio electronics, which sometimes come across, at least, as lacking in grip, heavy-handed or soft-edged – or a combination of the above.

But not in this case. The CDE is a well judged design that has got it just right. Without being in any way obvious about it, this is, above all, a relaxed, easy-sounding and genuinely musical player that nevertheless gives a broad, expansive stereo image and an unusually positive impression of musical dynamics – never clipped or aggressive, but always cleanly articulated and always convincing.

Pure vocals

The easy on the ear quality is something that often comes as standard with valve electronics, but usually there is a price to pay. In this case, the achievement is just about seamless, the only possible and very mild criticism being a hint of softness at the very lowest frequency extreme.

The mid and treble are of a different order – fast, expressive and almost luxuriantly coloured at appropriate times. Strings for example sound distinctive and homogenous in an orchestral setting without being homogenised.

Vocals have a real passion and purity and piano has the right mix of percussiveness and sustain, retaining the authentic 'voice' or personality of the instrument. The end result: music reproduction that breathes, that sounds expressive and that simply gells.

It took about three A-B comparison runs between the two DAcs before we quite suddenly achieved these results. The upgrade DAC sounds (tonally, at least) in many ways similar to the standard model, presumably because so many of the audio components and sections are shared.

But the upgrade DAC, in fact, has a clearly superior instrumental and vocal separation, giving a feel of greater contrast and range and for this reason a superior impression of dynamic shadings, especially in more subtle, undemonstrative musical passages that don't naturally show high levels of internal contrast.

Performance passion

The bass, too is just right, if arguably not quite as authoritative as the best of solid-state as implied earlier, but the mid and high frequencies are notably sweet and pure.

This was clearly audible in a recently acquired disc of Grieg, including the evocative music used as the soundtrack for the recent Joanna Lumley TV programme about the Northern Lights.

Through the Unico CDE, the music, which when reproduced with less distinction can sound hackneyed, sang with an understated, but still very real passion that made the hairs on the back of the neck rise.

There were similar experience on offer with other recordings, one very good example of which was the second movement and the vocal finale from the excellent Bernard Haitink/Royal Concertgebouw orchestra version of Mahler's 4th symphony. In both cases and with a number of other recordings, too the sense of a living, breathing sound stage was palpable.

Well-priced deck

There's a feeling among many hi-fi devotees that valves often lead to a lazy attitude to design – which does many things superficially right, but when push comes to shove often doesn't work. This player is the opposite: a design based on a clear understanding of what valves can and can't do and which doesn't fall for the usual pratfalls.

The Unison Research Unico CDE is, in short, an excellent player, well built, well priced and one that plays music extremely well, with great purity, expressiveness and range, irrespective of its enabling technology.

And it benefits from an unusually welcome degree of flexibility, thanks to the upgrade able DAC option from the factory plus its ability to act as a simple, high-quality D/A converter for external digital sources.