Resolution Audio Opus 21 CD player reviewed

Overview: Price: £2850 Website: www.resolutionaudio.com Spec: Four BurrBrown PCM 1704 24-bit converters,16x upsampling DIN, XLR balanced & phono ouput sockets Analogue-domain volume control Digital input (up to 96kHz) Size: WxDxH: 24 x 25 x 7.5 cm (each component) Total weight: 3.5kg

Established in 1993 by Jeff Kalt, Resolution Audio is a small San Francisco based brand which has an unusually small but well formed range of products consisting of this two box CD player and an integrated amplifier that integrate more closely than most. The latter is actually a DNM design in a Resolution case, one that exactly matches that of the Opus 21 - player and amplifier featuring a multi-pin connection system in the top and bottom of their respective chassis. Look underneath the transport section of the Opus 21 and you will see a serial style plug that connects directly to the matching amplifier when the units are stacked. This approach also extends to the Opus 21 which has also had design input from Dennis Moorecroft (DNM).

The Opus 21 is a two box CD player with a difference. The accepted thinking with high end players used to be that you put the disc drive or transport in one box and the digital to analogue converter or DAC in the other. This philosophy began to lose its sheen when a specific type of digital distortion called jitter was discovered in the early nineties. Jitter is often increased when a digital signal is transferred between separate boxes and this has spawned an increased interest in single box players, even very expensive ones.

The two boxes that make up the Opus 21 represent a new approach to these issues. Here one unit contains the transport, DAC and analogue output stage, while the other houses the display and power supplies. This splits the critical audio oriented elements from the 'noise' making parts whose radiations have a tendency to upset the analogue and digital sections of a player. It is such an obvious way of tackling many of the problems of CD reproduction that I'm surprised no one else has tried it. I guess this is how Jeff Kalt and Dennis Moorecroft came together, both have the ability to work 'outside the box', as those Yankees are apt to say.

The Opus 21 units are connected by a multipin umbilical with mains power plugged into the display unit only. It seems slightly surprising that the casework connection approach chosen for amp and player wasn't used for these two boxes, but the idea is to separate the problems of one from the other so you are not encouraged to stack them. Having said that it turns out that placing the section with the display on top of the disc driving audio section seems to give the best results.

Output connections include volume controlled single ended and balanced outputs, a digital input (for signals up to 96k) but no digital output and a fixed level DIN output. The latter very much a DNM thing, but it is not alone, even the mighty Naim in its increasingly mass market form still uses the pesky things, a nuisance because suitably terminated interconnects are not so common.

The Opus 21's volume control is hardly an innovation, such devices could be found on many early CD players, but it's a rarity on serious contemporary machines. Resolution Audio has put a high quality volume control in the analogue domain, eschewing the bit reduction technique used by brands like Wadia, in favour of more traditional technology. The Opus 21 has a numerical display for level and is claimed to drive any power amp.

Sound quality

It took an immense effort of will to go back to a more traditional preamp in the chain system after using the player directly injected. The DI result is simply stunning, the transparency being so high that even hard bitten reviewers like me are inclined to start tweaking racks and cables to squeeze the last ounce of performance from the rest of the system. I tried balanced and single ended connection, and got the best results with the single ended. but that may be because I have better single ended interconnects (Living Voice), a balanced LV interconnect might give better results still.

Resolution Audio is the right name for this player, it has remarkably high resolution and you'll find plenty of more expensive players that won't match it. It seems to excel in the areas where most CD players are struggling, namely dynamics/energy, stereo imaging and naturalness of tone. The degree of solidity and presence to instruments is quite uncanny and will have you poring over your CD collection to find out which are the best recordings. These are not always the ones you expect either. Granted my ECM discs have a richness and realism that puts them way above the norm but less likely sources such as Elbow's Asleep in the Back also offer unusually high fidelity despite all the multitracking, compression etc. used in the studio. I found myself unable to take the disc off because it sounded so compelling through this player. Which is not something that often happens with a well used test disc.

The limitations of a Bryston BP25 preamplifier are not so great (they are in fact not great at all) as to undermine this level of quality and the player continued to shine when connected via a DIN to phono cable to this preamp. The quality of timing became more apparent in this configuration, something that few disc spinners offer with this degree of subtlety and precision. It's not a hard edged thing either, this is a fine and extremely revealing player that tells you what's on the disc without apparently adding anything of its own - which is still quite rare with digital electronics. It reflects what the musicians did in the studio, if they played hard and fast that's the way you'll hear it, except you'll also hear all the harmonics and lower level sounds more clearly as well.

The Opus 21 encourages collection exploration, even if you've had a great CD player for some time. You'll find more inner detail and tone colour on your discs than you will have heard before. Bass is particularly well resolved, even juicy. Whether it be a male voice, double bass or piano, you can hear texture and tone colour that eludes most of the competition. This may seem like an expensive CD player but in the grand scheme of things it's a steal.

Verdict:

Real high resolution at a competitive price, this is a very impressive player in all respects, forget new formats, with one of these your existing CDs will sound twice as good.