Unison Research Unico Pre Preamplifier and Unico DM Power Amplifier (Hi-Fi+)

Equipment+
Categories:
Solid-state power amplifiers,
Tubed preamplifiers
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Products:
Unison Research Unico DM,
Unison Research Unico Pre
Unison Research Unico Pre Preamplifier and Unico DM Power Amplifier (Hi-Fi+)

Unison Research really lives up to the name; it’s a true unison; a combination of loudspeaker manufacturer (Opera) along with two parallel electronics brands ? the all valve Unison and the valve/transistor hybrid Unico ranges. The Italian company has one of those richly deserved reputations for building lovely looking products, and even if the powder-coated Unison models represent the diffusion line, these aren’t exactly fugly products, either.

The looks are new, even if the names aren’t. There was a Unico preamplifier that came before, also called the Unico Pre. But that was big and tall and slightly clunky looking line-and-phono affair, where the new Pre just looks like a well-built, standard sized one-box line-only preamp. It’s a hybrid design, featuring J-FETs in the input stage and ECC82 double triodes in the gain stage. This, the company considers, gives the best overall balance; the J-FETs for linearity, the triodes for four-o (smooooth) smoothness across the mids.

It’s a four-input pre, marked CD, tuner and two auxiliary inputs. There’s also a tape monitor circuit. The inputs are run through both balanced and single-ended pathways, with a selector at the front. In theory, you could run four separate balanced and four single-ended sources (and the single-ended only tape) through the Pre. The chassis is laid out dual-mono style, with all the left and right channel inputs and outputs at either side of the pre, and the IEC mains and odd-ball spring-clip speaker cables-for-amplifier link in the centre of the rear panel. Each side of the Pre has one balanced and two single-ended connections to the power amp.

The DM power amp is also derived from its squared-off predecessor. It’s still a big case, but shorter and wider than before. The DM name is short for ‘Dual Mono’, and once again it’s two amplifiers in a box, sharing a common central power supply. The 150 watter is capable of being driven in bridged mode, at which point its power rises to a whopping 500 watts per channel. Like the Pre, the DM is a hybrid design, but this time uses a pair of ECC82s in the input stage (again, think smooth, this time just a three-o) and push-pull MOSFETS at the meaty end. It can be used in balanced and single-ended mode.

Aside from the more conventional lines, the biggest changes to the amps involve increased logic control, especially on the Pre. Both models still have soft-starts and carefully controlled warm-ups (no sound for the first 30 seconds to give those tubes a gentle nudge into life), but now without the pink light show from the power button. In addition, the Pre now moves source selection from a simple four-position rotary dial to a logic-driven affair. This means little green indicator LEDs at each source and a central LED volume display. It also means the control surfaces have some of the worst feeling knobs around, completely free from resistance and with some deliberate play. This isn’t a deal-breaker, as it’s a sign of moving away from ‘hard’ controls on the front panel, but some still want their volume dials to feel ‘right' and that’s not going to happen here. The remote, on the other hand, feels wonderful thanks to its wooden back panel. Unison alternates between handsets with the bare minimum of buttons and ones that can control anything in a 20 metre radius. This falls into the latter category ? given the limited level of control on the front panels, this handset can operate balance, control matching CD players and more. Comprehensive, but you might spend a lot of time swearing at it because the pause button looks identical to the station selection control.

There is a schoolboy error to the reporting of the sound of the Unico Pre and DM, one that I confess to (almost) making. It’s a remarkably natural sound, which can easily be dismissed as a ‘soft, smooth, rock-free wallpaper’ approach. This is almost a knee-jerk reaction to Italian amplifiers, as if we can’t get past it coming from the land of gelato. But Italy is the land of espresso too, and there’s more strength behind that smoothness.

If you begin with John Martyn and travel all the way to Lambchop, you’ll hear a sumptuously natural, inviting presentation, with plenty of detail and good dynamics. There’s something of the hybrid to the sound; not in terms of triodes and solid-state, but the way it manages to convey much of what American audiophiles look for in audio (expansiveness, precise and three-dimensional imagery, and that sort of macro-lens up close dynamic contrast and detail) while retaining a lot of what ticks the box for British hi-fi buffs (a sense of rootedness to instruments within a soundstage, well-ordered and deep bass and a good sense of rhythm).

Even here, it’s easy to still fall into that trap of thinking the Pre and DM are ‘nice’ rather than ‘good’. But it’s here you turn to the darker, stormier side of things; nasty, kiddy-scaring music like Tool or John Pickard, or grunty, rude bass-heavy leftovers from the 1990s like Leftfield or Aphex Twin. Even some evil jazz from the likes of Fringe Magnetic. It takes the lot in its stride and dispels the notion that this is merely some kind of laid-back smooth ride.

Whatever you put through the Unico duo comes out extremely natural sounding. The sense of scale to instrument sounds, and the way those instruments separate out within the soundfield is particularly exact and beguiling. It’s not an imposition on the sound and the duo won’t try to turn processed pop into events dripping with ambience. But it does seem to step out of the way more readily than most.

Then there’s the bass. Rich, deep and full, it can be understated when the music demands it and gut-churning when called for. This is the one time where the Pre takes a step forward past the DM though. The amp, though very good, doesn’t have that sort of absolute control over the drive units as demanded by some of the more demanding loudspeakers. This may change when used bridged, but this isn’t the first choice to drive amp-crusher speakers like the Magico Mini II. That’s pushing it way out of context though, and in partnership with the sort of speakers you might expect on the end of a few grand’s worth of amp (I used ProAc Response D Twos), it worked like a charm.

There’s still a touch of softening to that naturalness on single-ended inputs and especially on the single-ended pre-to-power connection. On, ahem, balance, the sound of the amps in balanced mode is perhaps preferable to single-ended. Not by any significant amount, but balanced just seemed to give music an edge that it lacked in single-ended. Drums were snappier and tighter, with the buzzing decay of the snare springs more ably delineated from the beat itself. This wasn’t down to improved detail in balanced mode, but the fact that the single-ended combo could sound too smooth at times, as if it were papering over cracks that didn’t need papering over. A lot of this might come down to personal taste (in part because the difference is not substantial); if you listen to a lot of power chords, balanced will do it for you, but if your music tastes are pitched more toward the Francois Hardy/Scott Walker school, go single-ended (we could make the same statements between Beethoven and Mozart, or between Thelonious Monk and Dave Brubeck). So, when it comes down to it, I’m not sure if the ‘preferable’ part of balanced mode here is actually ‘preference’. I’d certainly be happy with the amp in either mode.

Splitting the two apart for a brief period showed both were very good at their jobs, but were such an obvious partnering that the chances of someone considering one without the other seems almost absurd. They work together like conjoined twins. If you do split them apart, the pre has a character not unlike a classic Conrad-Johnson model, while the power sounds a little like a Counterpoint or Coda. In other words, taken separately, the sound of each starts to sound less ‘honest’ and more ‘warm’, but in combination the two ‘warm’ sounds patently cancel one another out.

I must confess to holding on to this amplifier for a lot longer than a reviewer has any right to. In part that’s simply down to sheer weight of hi-fi traffic in the review roll-call, but another part simply didn’t want to give it back any time soon. It may not have the sort of cachet of the big names in the game, and it doesn’t make for shiny-shiny audio sounds that instantly attract listeners, but instead the Pre and DM play the long game. They are the natural choice for long-term listening.

TECHNICAL SPECIFICATIONS

UNISON RESEARCH Unico Pre
Line inputs: Four balanced and single-ended inputs, one tape monitor input
Outputs: One balanced and two single-ended outputs, one tape monitor output
Valves: 2x ECC82 (12AU7/5814A)
Bandwidth: 10 Hz - 100 kHz at -+ 0.5 dB
Input impedance: 47 kOhm
Output impedance: <100 Ohm
Power consumption: 700 watt maximum
Dimensions (WxHxD): 240x170x520mm
Net weight: about 12 kg
Price: £2,160

UNISON RESEARCH Unico DM
Balanced and Single-ended inputs
Output power: 150 watt per channel
Bridge mode: 500 watt
Output impedance: 2 - 8 Ohm
Bandwidth: 2 Hz - 100 kHz at - 0.5 dB
Input impedance: 20 kOhm / 15 pF
Output Stage: Improved dynamic class A symmetrical with power MOSFET complementary pair
Damping factor: > 50
Total feedback factor: 9.3 dB
Power consumption: 700 watt (at full output power)
Dimensions (WxHxD): 240x160x440mm
Net weight: 18kg
Price: £2,880

Manufactured by: Unison Research
 www.unisonresearch.com

Distributed by UKD Ltd
Tel: +44(0)1753 652669
www.ukd.co.uk

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