{"id":21888,"date":"2026-10-03T11:05:37","date_gmt":"2026-10-03T09:05:37","guid":{"rendered":"https:\/\/audio-2g.com\/?p=21888"},"modified":"2026-10-01T10:43:25","modified_gmt":"2026-10-01T08:43:25","slug":"unison-research-unico-dm-v2-and-unico-pre","status":"publish","type":"post","link":"https:\/\/audio-2g.com\/en\/unison-research-unico-dm-v2-and-unico-pre\/","title":{"rendered":"Unison Research Unico Dm v2 and Unico Pre"},"content":{"rendered":"\t\t
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Unison Research<\/a> Audio 2G has tested\u2014and, incidentally, with great satisfaction\u2014several tube integrated amplifiers, notably the following models <\/i>Simply 845<\/i><\/b><\/a>, <\/i>Simply Italy <\/i><\/b><\/a>and <\/i>S6 Black Edition<\/i><\/b><\/a>. However, the company based in Dosson di Cassier, in the province of Treviso, has for years included in its product line a series of hybrid amplifiers\u2014that is, amplifiers that combine solid-state and tube technology\u2014called Unico. In the specific case of this review, we are examining the new version\u2014V2, to be precise\u2014of the Unico Pre and the Unico Dm, which date back to 2008. This should give us pause to consider just how long the models offered by this Italian manufacturer remain in the catalog and how thoroughly technological innovations are refined and developed before being incorporated into a new model.<\/i><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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One of the most iconic models in the Unison Research tube amplifier series: the Absolute 845, which makes extensive use of high-quality wood and copper in its cabinet. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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A little history.<\/b><\/h2>

Unison Research was founded in 1987 by a group of passionate audiophiles, led by Giovanni Maria Sacchetti (1945), who later drew on the entrepreneurial expertise of Giovanni Nasta. Sacchetti devoted himself to the study and design of hi-fi systems from a young age, combining his interest in electronics with a passion for music inherited from his father, a talented pianist. After completing his studies in electronics, he devoted himself to teaching, as well as to the design and development of Unison Research amplifiers. Another pillar of the Treviso-based company is Prof. Leopoldo Rossetto, a full professor of advanced analog electronics at the Faculty of Engineering at the University of Padua, whose design insights form the basis of the A.S.H.A. technology, which I will discuss later in this article. I\u2019d like to acknowledge the contributions of two other engineers to the development of Unison\u2019s latest products: Alessio Fusaro, whom we\u2019ve already interviewed regarding previously reviewed products, and Agostino Zamai, a student of Prof. Rossetto who served as his thesis advisor.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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The Unico Pre+DM v2 combo in Midnight Black. The wood accents on the power switch could be seen as a sort of nod to the model in the previous image.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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Aesthetic design.<\/b><\/h2>

An aesthetic analysis of Unison\u2019s new preamp and power amp\u2014if conducted with a casual eye\u2014might lead to the mistaken conclusion that the design is understated and elegant but lacking in points of interest. Nothing could be further from the truth. If you focus on the edges of the front panels, you can appreciate the subtle variation in their thickness, as well as the unique shape of their edges, which taper from one side to the other. The other surfaces are also finely crafted: the metal covers are perforated to form the Unison logo, while the side panels\u2014also perforated\u2014feature a pattern reminiscent of a musical signal envelope, as one might see it on a computer display. Aesthetics aside, it is worth noting that the front panels are made of 15 mm-thick solid-machined aluminum, while the other surfaces are 2 mm thick, contributing\u2014thanks in part to some clever design features\u2014to a highly rigid structure that prevents the occurrence of unwanted mechanical resonances. Personally, I found the beautifully crafted wooden power switch delightful: a sort of nod to the defining characteristics of the tube amplifier series, whose cabinets make extensive use of this noble material.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Unico Pre<\/b><\/h2>

The abbreviation “DM,” which identifies the ending, unequivocally indicates the nature Dual Mono<\/i> of that product. It\u2019s true that the same model number could also be used for the preamplifier, and the first clue to this is the \u201calmost symmetrical\u201d layout of the rear panel, with all the connections for the two channels arranged mirror-image to the vertical axis. I wrote \u201calmost\u201d because, in fact, the perfect symmetry is \u201cspoiled\u201d by the pair of RCA connectors for the MM\/MC phono input located on the right. Nevertheless, the circuitry of this section is also dual-mono, right down to the PCBs, which are separate for the two channels, L and R. Also on the rear panel, we find two sets of DIP switch <\/i>for selecting the type of pickup, adjusting the electrical parameters, and, if necessary, increasing the gain by 10 dB. There are four line inputs available, three of which are dual inputs in both balanced (XLR) and unbalanced (RCA), and a single RCA input that can be used\u2014after appropriate configuration via a menu accessible from the front panel and navigable using the alphanumeric display\u2014to connect an external processor, creating a sort of \u201ctape monitor.\u201d<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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The layout of the rear panel is completely symmetrical with respect to the vertical centerline, with the exception of the RCA connectors for the phono input. Note, however, that the DIP switches for the corresponding adjustments are also positioned symmetrically at the ends, since they belong to two separate PCBs for the two channels.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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The digital input section is located on a dedicated board and includes four S\/PDIF inputs (2 optical and 2 coaxial) and an asynchronous USB port (XMOS chip) capable of handling PCM data streams up to 384 kHz and DSD up to 256x. The chipset used is the Sabre ES9018K2M, whose balanced-output architecture integrates seamlessly with the Unico Pre\u2019s tube circuitry, ensuring high-quality conversion and tonal consistency. Our tests were conducted in a Linux environment (Audiolinux) and confirmed full compatibility. The Unico Pre is inherently balanced and, consequently, uses a Burr Brown PGA2311 stereo chip for each of the two channels to control volume. Although these chips are capable of handling a 120 dB dynamic range in 1\/2 dB steps, in this case we chose to limit the range to 59 dB using 74 levels with varying steps: 1\/2 dB for levels between \u201c99\u201d and \u201c29,\u201d 1 dB between \u201c29\u201d and \u201c10,\u201d and finally 2 dB for levels below that. Once the cover is opened, the dual-mono architecture is immediately evident due to the mirrored layout of the main PCB, at the center of which is a large connector that carries the various power supply branches from the dedicated separate section, which, as expected, uses a toroidal transformer of considerable size. From a circuit design perspective, the Unico Pre, like the Unico DM v2 power amplifier, uses vacuum tubes for the analog input stage\u2014specifically, an excellent Genalex Gold Lion ECC83\u2014along with discrete transistors and integrated circuits. The main PCB is built using through-hole technology, while the digital board, the two volume boards, and the phono section boards are manufactured using SMD technology.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Once the cover is removed, you can see that the design is essentially dual-mono. Note the two Genalex Gold Lion ECC83 tubes. On the left, resting on the table, is one of the two volume control boards equipped with the Burr Brown PGA2311 chip.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Unico DM v2<\/b><\/h2>

The first thing that stands out about the rear panel is the size of the two large 750 VA toroidal transformers, which take up a significant portion of the interior space. Looking at them from above, you can see that they have been secured together using a shaped metal plate. The heat sinks, which are large and thus have a substantial radiating surface area, are also connected to each other by a metal bracket that runs across the unit from side to side. Perpendicular to this bracket are two additional metal brackets that connect the front and rear panels, helping to improve the overall mechanical rigidity of the unit. Significant attention has been paid to minimizing vibrations through strategically placed neoprene pads in certain areas. The power amplifier also features a clear dual-mono layout. The Unico DM v2 power amplifier is a hybrid design, featuring a Class A tube first stage with two ECC82 \/ 12AU7 Gold Lion tubes, while the second stage employs an innovative complementary push-pull configuration with three pairs of MOSFETs (IRFP240\/9240) in parallel.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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At least half of the internal volume is taken up by the two toroidal transformers. Note the dual-mono configuration here as well.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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With this model, Unison Research introduces A.S.H.A. technology for the first time; the acronym stands for Analog Synchronized Hybrid Amplification<\/i>. This technology gives rise to a unique power amplifier configuration known as Class A-AB, which combines the musical qualities of Class A with the efficiency and reliability typical of Class AB. Care must be taken not to confuse this configuration with the one widely used for decades known as Class AB, where the active devices initially operate in Class A and then switch to Class B when power demands require it. Here, the amplifier operates constantly in Class A and activates the complementary stage in the negative half-wave only when necessary. For a detailed description of A.S.H.A. technology, please refer to the video uploaded to our YouTube channel, where engineers Fusaro and Zamai explain it in precise terms that are still understandable even to those without specialized knowledge of the subject.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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From a user interface perspective, the Unico DM v2 power amplifier is extremely intuitive: on the front panel, you\u2019ll find the main power switch embedded in the wooden Unison logo, along with two small buttons, each paired with an LED. One button activates the RCA\/XLR switch, while the other activates standby <\/i> mode ( <\/i>energy-saving mode). On the rear panel, there are two pairs of speaker terminals\u2014useful for bi-wiring<\/i>\u2014and a switch to toggle between Stereo and Mono modes.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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The rear panel features superbly crafted binding posts designed for bi-wiring. Note the switch for mono operation of the amplifier.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Unison Research Unico Dm v2 and Unico Pre:Listening<\/b> Impressions<\/h2>

The listening test of the Unison Research setup was conducted by connecting an excellent pair of floor-standing speakers downstream\u2014the B&W 804D5s\u2014whose review you can read here<\/a>. Equally excellent was the source component\u2014in this case, the Rockna Wavedream Reference<\/a> DAC\/streamer, which we\u2019d also reviewed for our YouTube channel and website. In short, a top-notch system designed to allow this preamp and power amp\u2014from which we had very high expectations\u2014to perform at their very best. And our expectations were not disappointed; in fact, we were truly impressed by something I wouldn\u2019t hesitate to call innovative. What? Simple: the sound. That\u2019s right, because the Unico Pre and the Unico DM v2 combine power\u2014more than enough to bring out the best in the demanding 804 D5s\u2014and the refinement I\u2019ll discuss later, with a particular quality of sound that, at least at first, left me taken aback. I\u2019m referring to the fact that these components perform the same way at low, medium, and high volumes. Let me explain: you\u2019ve probably noticed that every system has a well-defined range <\/i>the volume range within which it sounds best. If the volume is set too low, the sound lacks energy and definition, falling short in terms of focus and clarity. If it\u2019s set too high, tonal coherence begins to diminish, the soundstage flattens out, and the subtle, detrimental effects of distortion start to become noticeable. Well, none of that happens with these new Unison speakers, which, from the very first notes, give you the feeling that you\u2019re hearing the very best the system has to offer, regardless of where the volume knob is set. At low volumes\u2014perhaps during an \u201cintimate\u201d listening session late at night\u2014this characteristic ensures you don\u2019t miss a single nuance of the musical message in the track you\u2019re listening to. Conversely, at high volumes, you can reach stadium-level sound pressure without even realizing it. In our test, the sign that something out of the ordinary was happening was the unusual excursion of the B&W woofers, which were driven hard by the Italian duo without any apparent strain. That said, it\u2019s clear that there\u2019s always a \u201cnatural\u201d volume level at which listening should take place, and that this level varies depending on the track\u2019s content. In short, listening to Dream Theater<\/i> is one thing, a Mahler symphony is another, and a string quartet is yet another. Certainly, the Unison Research pair is capable of accompanying us through all these very different listening experiences, always guaranteeing a sound devoid of even the slightest hint of distortion. <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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The side and top panels feature decorative cutout patterns. In particular, the Unison logo is clearly visible.<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t
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There\u2019s a track that I love very much and that has been on one of my listening test playlists <\/i>for years: \u201cBehind the Yashmak<\/i>,\u201d taken from the<\/i> Esbj\u00f6rn Svensson Trio\u2019s *Live in Hamburg*<\/i> (ACT 2007), which has allowed me to appreciate the unique character of the Unico pair. The track opens with an acoustic double bass solo by Magnus \u00d6str\u00f6m, which gradually increases in complexity, accompanied by some subtle electronic sounds. Here, the Italian amplification system performs with great authority and control, successfully reproducing the full richness of the acoustic instrument\u2019s sound with admirable precision. This is followed by the main theme developed by the late Scandinavian pianist, which unfolds into a dizzying crescendo into which Dan Berglund\u2019s drums are woven. The timbres and harmonic nuances, of both the piano and the double bass, have been reproduced with the utmost fidelity\u2014both in the initial pianissimo passages <\/i>and in the final climax <\/i>\u2014where the exceptional power of the Unico DM v2 amplifier, combined with the absolute absence of distortion, gave me a tremendous thrill. Thanks to the excellent recording, the live <\/em> feel is <\/em> truly intense, and\u2014believe me\u2014for me to write something like this, it\u2019s not just the usual clich\u00e9. <\/p>

The test case of symphonic music only serves to confirm my impressions. In particular, the clarity of the musical message during pianissimo passages ensures that the listener doesn\u2019t miss a beat, allowing them to attune themselves to the compositional structure of the score. The first movement (Allegro moderato) of the Concerto for Violin and Orchestra in D minor, Op. 47<\/i> by Sibelius, performed here under the direction of Klaus M\u00e4kel\u00e4 with the Oslo Philharmonic Orchestra and featuring Janine Jansen as soloist (Decca), opens with an introduction by the strings in tremolo<\/em> This is followed by the soloist\u2019s entrance, presenting the main theme, which is expansive and expressive. With other amplifiers, I\u2019ve found myself having to turn up the volume a bit to fully appreciate the ethereal\u2014typically Nordic\u2014atmospheres during the opening moments of playback, only to have to suddenly turn it down when the entire orchestra enters in the finale. With the Unison Research pair, I didn\u2019t need to do that at all, thanks to their exceptional resolution and microdynamics at low volume levels.<\/p>

As mentioned at the beginning of this paragraph, these listening impressions are based on use with the Rockna DAC\/Streamer, but how does it differ when using the built-in DAC? Well, with the same source\u2014namely, the Roon server running on my Antipodes K30\u2014the difference proved to be quite marked across all parameters, but what stood out most was a slight loss of tonal accuracy. Worthy of note, however, is the phono stage, which is quiet, dynamic, and tonally accurate. <\/span><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Conclusions<\/b><\/h2>

As you know, I don\u2019t have a background in electronics, so what I\u2019m about to write may not be of any value. However, I believe that in an industry where countless technical solutions have already been tried and tested\u2014and where what\u2019s presented as technological innovation is often little more than a \u201ctweak\u201d to technical solutions dating back several decades\u2014Unison Research\u2019s offering struck me as a genuine innovation. What I\u2019m reasonably certain of is that this Unico Dm v2 and Unico Pre combination delivers a distinct sound of decidedly high quality. If we add to this a versatility that leaves no room for criticism, a high standard of build quality, and\u2014a detail not to be overlooked\u2014an overall cost that is, all things considered, comparable to that of a high-end integrated amplifier, I\u2019d say that once again, Unison has hit the mark. If you have the chance, I recommend going to listen to them.<\/p>

Giulio Salvioni<\/i><\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t

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Technical Specifications<\/h2>

Unico Pre<\/h3>