Unison Research Simply 845 Integrated Amp Review

Published On: January 11, 2009
Last Updated on: October 31, 2020
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Unison Research Simply 845 Integrated Amp Review

Ken Kessler compares the Unison Research Simply 845 tube power amp to an Audio Note Ongonku for one fifth of the price. Can this sexy, yet affordable amp live up to this much audiophile hype. Read more to find out.

Unison Research Simply 845 Integrated Amp Review

By Author: Home Theater Review
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Although my own experience of Unison Research during its first decade has been limited to a mere three products, I must have chosen wisely for two of them were leading up to the Simply 845. From the Simply Two entry-level single-ended integrated amplifier, it borrows the basic layout of an elongated chassis with the valves at the front and the power supply at the back, the controls on a horizontal plane, the wooden trim. From the Smart 845 monoblocks it borrows the basic amplifier stage. Even its name is something of a hybrid. (I'm biting my tongue as far as the company's use of English is concerned.)

Additional Resources
• Read audiophile power amp reviews from the likes of Krell, Mark Levinson, Audio Research, Linn, Naim, VAC, VTL, NuForce, Pass Labs and many others here.
• Read about tubes on the Audiophile blog, AudiophileReview.com.
• Want to read audiophile stereo preamp reviews? We have dozens from brands like ARC, Krell, Classé and many more.
• In the market for audiophile loudspeakers? Here are over 100 reviews from brands like Wilson Audio, THIEL, MartinLogan, Bowers & Wilkins, PSB, Vandersten, Magnepan and many more.

The Simply 845 - given its world launch at the Hi-fi Show - not only upholds but further develops two traditions which have made Unison Research one of the most successful valve amp manufacturers in the world: (1) a sane pricing policy which almost qualifies as under-pricing, and (2) looks which make you say, "Gimme!" For the first, get ready to welcome a massive, superbly constructed integrated amplifier which instantly identifies itself as an Ongaku for around five percent of the latter's price: £2950. For the second, well, just look at the pictures...

As with the earlier gems, the Simply 845 is styled by Carlo Chiarello to marry both functionality and elegance. He favours asymmetrically sculpted sections of solid cherrywood for the front panel and the side trim, and it's this which - more than anything - identifies a Unison Research product. The rest of the case is matt black with a warm, 'tactile' paint finish, applied even to the ribbed heat-sinks. As was first seen in the Smart 845, a novel heat shield creates a barrier between the massive valves and the circuitry. For the earlier model, it was a 'chimney' made of ceramic; for the Simply 845, a sheet of curved stainless steel reflects the heat away from the delicate bits.

But with Unison Research, it's in the details. Despite the topological simplicity of a tube integrated amp - a case, a couple of switches, a rotary control, some sockets - Chiarello manages to add deft touches which you might not even notice for a few weeks. There is, for example, a tiny strip of a heat sink in between the two large capacitors, behind the stainless steel barrier; buried in there and coloured the same grey/black as the rest, it's easy to miss. The stainless steel of the barrier is repeated as an overlay on the horizontal surface which holds the controls and the valves. There are subtle gold accents ranging from the plating of the terminals and sockets to the colour of the controls. The supports for the stainless steel shield match the gold of the controls. Even the case itself is deceptive.

Your eye tells you that it narrows toward the back because the front half of the '845 features the wooden side panels which increase the frontal dimension. But then you notice that, even with the wood subtracted from the case, the front is still wider, 350mm as opposed to the rear panel's 320mm. I have no idea what amount of craft it takes to fold sheet metal into a four-sided case with non-parallel sides, but this was deemed desirable in the same way that speaker enclosures are designed not to feature parallel innards. By the way, prepare your equipment rack to accept a monster measuring 600x390x260mm (DWH) overall and weighing 35kg.

The rest is the work of Prof. Giovanni Sachetti, who has designed all of the electronics for the company he co-founded. Along with the evolutionary process mentioned above, the Simply Four integrated amp (the Simply Two's big sister) provided elements of the input stage, uprated as appropriate and coupled to the output stages of two Smart 845s. Sachetti prefers the most direct circuit possible, so the signal paths can be seen to trace the same route as they appear to follow externally: the input stage to the driver stage section works precisely as the input sockets and valves appear on the outside, from left-side front of the chassis to centre-front. The power supply capacitors are mounted mid-chassis, directly behind the input section and the vales, with the transformers mounted at the rear close to the speaker terminals.

Naturally, the operating mode is single-ended pure triode, with a useable power output of 24W/ch. I've made no bones about the 845 valve being one of my all-time fave tubes; it's always been a favourite of Prof. Sacchetti, too. (Amusingly, the company bowed to public pressure and created a design using that over-rated piece of shit, the 300B, but refused to be forced into producing yet another gutless wonder; the company's flagship Palladio uses four 300Bs to provide a 'sensible' 30 watts from each monoblock.) And although Sacchetti has referred back directly to the Simply Four and Smart 845, the Simply 845 uses higher rated components in certain key places, e.g. the bridge rectifier.

What fans of the Simply Two and Four will notice as missing is the variable feedback switch; the Simply 845 doesn't require it because it's a zero-feedback design as per the Smart 845. What controls remain include the AC switch at the back, the volume control at the front (under an arch formed by the wooden fascia's left-hand section), a tape/source monitor switch and a rotary to choose one of the four line level inputs. That's it. The Simply 845 features a special socket at the back for connecting the company's dedicated, stand-alone Simply Phono stage, while speaker connections consist of large, Michell-like multi-way connectors. Oh, and they offer a choice of 4 or 8 ohm impedances, necessary when you don't have wattage to waste.

Black chassis, wooden trim, stainless steel fittings: all of these force the eye toward the valves they frame. The four small tubes at the front include two ECC82s and two ECC83s for the pre-amplification and driving stages. Behind them, the glorious 845s, with automatic biasing to ensure that this is as easy to use as any solid-state integrated amp. (Yeah, right, if you include the need for ventilation and a shelf supporting 35kg as to be normal integrated amp practices.) And it's only right that the two 845s, standing there like a couple of pillars forming the gates to sonic heaven, capture your gaze.

Why? Because 845s have a certain warmth, a way with the emotional content of the music which separates them from nearly all other tubes, bar the 211 and the KT66. Even with no-nonsense sources like the Krell KAV-300CD, surgically precise cables from Transparent and speakers as naked at the Quad ESL63s, the sound remains human, radiant, intense. No, make that 'Italian'.

Quite how it happens might have nothing whatsoever to do with the actual circuitry, nor the topology, nor even the 845 itself, so much as it has to do with pure attitude. It speaks volumes for Unison Research that nearly half of the owner's manual features a dissertation on how to hand-fashion woodwork, using centuries-old techniques originally mastered by instrument makers. And the wordage borders on soft-porn in its descriptions of the pleasure one gets from running one's hand along the warm, curved, golden, luscious - ahem, I was getting carried away there. Unison Research isn't obsessed with technology; it's obsessed with artistry. So what you get from the Simply 845 might be classified as interpretation rather than reproduction.

Which will be identified by measurements guys and all those who hate S.E.T.s as A Bad Thing, because the word 'interpretation' leaves room for inaccuracy. But that doesn't seem to be the case. The details, the bass extension, the speed, the dimensional and positional concerns, the tonal balance and everything else which we dissect when assessing performance remains as it should. There was no great shock moving from the state-of-the-art solid-state analysis of the Sutherland 2000 to the Unison, or from GRAAF's push-pull, 6550 traditional tubeware. It wasn't a sudden case of loss of information, or added coloration.

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As S.E.T. worshippers - even those seduced by the 300B - continue (incessantly) to remind those immune to their charms, the 'special element' is a mid-band richness which adds to the sense of involvement. More to the point, it realism, which might seem like a contradiction in terms. Realism is realism, and enhancements can only alter. But there's no other way to say that the music seems more real; only to accuse other technologies of sounding more like hi-fi. And maybe it's the core of the Tubes Vs Transistor battle which has been raging for a couple of decades. Which means that S.E.T.s must be the most undiluteded form of tube playback available, rivalled only by the far more rare OTLs.

So, rather than a hazy, cloudy form of updated anachrophilia, the Simply 845 provides a level of transparency and clarity with which modernists can feel comfortable, at the same time ensuring that vocals and acoustic instruments are not stripped of any of the presence or richness which separates hi-fi from music. No feeling of filtration intrudes, no clouding nor removal of desired edging due to the selection of 'vague' tubes (read: 300B). And any sense of reticence vanishes as soon as you try a recording with a single voice in front of an orchestra or chorus. Big Daddy's 'With A Little Help From My Friends' showed that the Simply 845 is not shy, that it hides nothing. The vocalist appeared stage-centre, the backing singers arranged behind. Neatest touch of all? The vocalist stood just in front of the line of speakers, the backing group just behind.

With even the often-too-polite Quad ESL63s, the sound had snap, power and forcefulness. Impact was provided as needed, while bass extension - heard through the Quads - proved yet again that Peter Walker was right about the ESL63's lower registers and everyone else was wrong. And the main question: the wattage? Better than adequate, if you don't mind the following unscientific observation: the Quad electrostatics and the Ruark Epilogues filled my 14x26ft room with the volume control at 11 o'clock, the hungry little Quad 77-10Ls at the half-way mark, Opera Plateas at 10.30, the old ESLs at 10 on the dot.

And the amp never overstepped its role, never inflicted too much warmth nor too much tubey-ness. And, referring back to my own particular belief - that designers' personalities can be found in the sound - the Simply 845 doesn't fail me: it has the gentility and sheer class of Prof. Sachetti, and the utter precision and command of his partner, Dottore Ambrosino. Those of you who met the pair at the Hi-Fi Show know that's a fairly accurate description of the two.

All of which makes the Simply 845 something of an ideal single-ended triode amplifier for those who want to avoid inconvenience, criminal pricing, crude construction and - most importantly - a lack of power or an excess of euphonic coloration. No S.E.T. will ever be populist - indeed, no valve amp ever will be again; the transistor saw to that. But for those who want their music alive and well and living in their listening rooms, one choice is - simply - 845. And when you hear it through the ESL63s, you'll know what an unbeatable combination 'Anglo-Italian' can be.

Additional Resources
• Read audiophile power amp reviews from the likes of Krell, Mark Levinson, Audio Research, Linn, Naim, VAC, VTL, NuForce, Pass Labs and many others here.
• Read about tubes on the Audiophile blog, AudiophileReview.com.
• Want to read audiophile stereo preamp reviews? We have dozens from brands like ARC, Krell, Classé and many more.
• In the market for audiophile loudspeakers? Here are over 100 reviews from brands like Wilson Audio, THIEL, MartinLogan, Bowers & Wilkins, PSB, Vandersten, Magnepan and many more.

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