Solid State Preamp Reviews

To look inside the preamp or the power supply was to understand why some hobbyists custom-order the DNM 3D with optional clear acrylic casework: While other engineers have praised such concepts as short signal paths, star ground schemes, and consistent signal-path spacing, those ideals are executed with greater care, ingenuity, and comprehensiveness in the 3D Six than in any other product I've seen, in any field. I can't imagine that artificial hearts, prenatal monitoring devices, or even missile-guidance systems are made with greater skill or precision.

Installation and setup
My review sample of the 3D Six preamp was delivered and installed by one of DNM's American reps, who also brought along a sample of DNM's four-tier equipment rack, designed to contain a full stack of DNM electronics. At the time the 3D Six was installed, my record player was the only source in use—and, as luck would have it, a mild but steady 60Hz hum made itself known the moment we powered up the system. We tried a couple of different grounding schemes for the turntable chassis and tonearm, which lessened if not quite eliminated the problem. Assuming the hum was just a phono thing and that I was well on my way to banishing it altogether, that's how we left it, with my hearty approval.

But despite my best efforts, the hum persisted with every phono cartridge in the house, and then and only then did I try rearranging the gear. The hum went away completely when I increased the distance between the preamp and its power supply. It seems that the worst effects of the power transformer's pattern of electromagnetic radiation are felt when the power supply is placed directly under the preamp itself; sliding the former rearward and the latter forward on their respective shelves took care of the hum, but it looked goofy. I ceased using the DNM stand and placed the 3D Six on other supports, taking advantage of all 45" of its power-supply umbilical.

Owing to the 3D Six's reliance on DIN sockets, not to mention its unusual if laudable grounding arrangements, I had to rely exclusively on DNM's own spaced-pair interconnects: 1.5m DIN-to-DINs for line-level sources, a very short phono-socket-to-DIN for my record player, a 1.5m DIN-to-twin-DIN for driving the DNM PA3ΔS amplifier, and a 1.5m DIN-to-phono-plug for driving all other amplifiers. I never experienced the slightest bit of hum with any of the unshielded DNM cables, but toward the end of the review period I encountered a slight intermittent hum associated with one of the phono-input sockets, apparently as a consequence of near-daily plugging and unplugging.

None of the amplifiers I used with the DNM preamp—Shindo's Cortese and Corton-Charlemagne, the Quad II, or Fi's 2A3 Stereo, not to mention DNM's own PA3ΔS—are balanced designs. However, prospective 3D Six owners should note that it can be set to a floated-ground mode for driving balanced amps simply by changing the switch settings on the line-amp boards, power-supply distribution board, and motherboard, as explained in the owner's manual. Switch provisions are also provided on those boards for selecting between normal and direct (noncapacitive) output modes. Ironically, there were no adjustment switches where I might have expected to find them: on the phono boards. The gain on those boards is fixed, as is load impedance (27k ohms for MM, a highish 1k ohm for MC), which prevented me from using my admittedly oddball EMT OFD 25, a high-output MC cartridge that overpowered the MC boards yet wanted a load under 500 ohms.

Listening
Let me remind you of my experience with the entry-level 3D Primus: Used with the tube amplifiers of my choice, that DNM preamplifier's most appealing characteristic was its combination of extraordinary clarity with a top end that was very extended yet utterly smooth and "organic," without any forcefulness or lack of naturalness. Its spatial performance was also strikingly good, with remarkable stage depth and detail: the sorts of things that often don't appeal to me at all, yet won me over when enjoyed in tandem with the 3D's undeniable ability to find the musical essence of most recordings. On the down side, my Shindo Masseto had more sonic texture and color and, most noticeably, greater bass depth and impact.

Good though the 3D Primus was, the 3D Six was better in virtually every way—although the distinctions weren't enormous, and I felt that the more expensive DNM sounded enough like the base model that few careful listeners would fail to hear the family resemblance.

Listening to Albinoni's Adagio in G Minor, performed by organist Philippe Lefebvre and the Orchestre du Festival under the late Tibor Varga (LP, Philharmonia PA 402 V12G012), I heard the 3D Six give more (realistic) weight to the low organ pedals than the Primus—though still not quite as much as the Shindo Masseto—as well as put across a greater amount of musically pertinent detail. As to the latter quality, switching from the humbler to the dearer preamp was like going from a good conductor to a great one: Certain lines were brought to the fore, seeming to be played with greater emphasis, feeling, and nuance.

Densely scored music of every genre was a delight: The 3D Six was literally unmatched in its ability to shine sonic light into the murk without making recorded music sound even the slightest bit bright. "Monkey & Bear," from Joanna Newsom's Ys (LP, Drag City DC303), which I daresay can't be appreciated without at least some awareness of its story line, came across with greater clarity than I'd heard before, its otherwise mildly unfathomable lyrics well untangled (footnote 2).

The DNM was also singularly good at clarifying—again, no other word for it—the thick orchestration of Strauss's Ein Heldenleben, played brilliantly well (and recorded ditto) by Fritz Reiner and the Chicago Symphony Orchestra (LP, RCA Living Stereo/Classic LSC-1807). That one also showed off the DNM's fine sense of scale: It sounded every bit as impressively, believably large as the Masseto—sheer bigness of sound being among the Shindo's great specialties. More important, as with all of the finest electronics I've tried, the DNM preamp allowed me to relax and enjoy the music as music: Through the 3D Six, the Strauss had a satisfying degree of emotional color—humor in particular, as it should have.

True to its rep for being true to the original, the DNM allowed overcompressed pop records to sound dramatically flat. Examples included such otherwise wonderful records as Mott the Hoople's Mott (LP, CBS 69038), Cat Stevens' Tea for the Tillerman (LP, A&M SP 4280), John Lennon's Imagine (LP, Apple SW 3379), even the Kinks' Lola versus Powerman and the Moneygoround, Part One (LP, Reprise RS 6423). Curiously, all of those selections sounded somewhat more stirring through the Shindo Masseto preamp than through the DNM; as always, and meaning no condescension one way or the other, it's up to the reader to decide which approach distorts the music and which does not.

But the music-making was of the highest order when I returned to comparatively uncompressed material—such as my favorite recording of Schubert's "Trout" quintet, by Clifford Curzon and members of the Vienna Octet (LP, Decca/Speakers Corner SXL 2110). Through the DNM 3D Six, the sound was open, clear, and, again, surprisingly big—surprisingly if only for the almost unavoidable subconscious association between small, light playback gear and small, light sound. But here the players and their instruments were spread a good distance from one another, each seeming to occupy the same generous space that they would in a real concert setting. Even the piano was beautifully huge, as was Johann Krump's double bass—although I missed that instrument's very deepest tones, of which my Shindo delivered a shade more.

Here, the DNM was every bit as good as the Shindo Masseto in its ability to portray realistic dynamic and dramatic peaks: Curzon's occasional lunges at the keyboard, some of which had escaped my notice through lesser electronics, always sparked my attention through the DNM, as did the consistently good portrayal of more subtle peaks and nuances. As Mahler said, what is best in music is not to be found in the notes—and so it was with this lovely record: Even the decay of the sound of each piano chord, especially in the early measures of the scherzo, seemed freighted with a degree of expression lost by most other playback gear, but captured consistently well by the DNM. For all its cleanness and timbral fidelity, the 3D Six never skimped on sheer expression: It played not just the sound, but the music.

Conclusions
When reviewing a new audio component in combination with a variety of associated equipment, as I do whenever possible, I intend my remarks to represent a sort of aggregate experience. So it goes here—but this time I'd like to shed light on some distinctions that might otherwise be missed.

In particular, when using the DNM 3D Six preamp to drive the many tube amplifiers at my disposal, it seemed that the characters of those amps were especially well presented, even brought to the fore. If anything, the wonderful Quad II monoblocks sounded even more rich and luxuriant than usual. The flea-powered Fi amp seemed more tuneful than ever, with almost startling presence—again, more than I'd expected. And the Shindo amps were amazingly colorful, dramatic, and alive, the different flavors of the two different models being clearly laid out.

Was all that down to the DNM's low output impedance? Its lack of coloration? Its tendency not to pollute its electrical surroundings with noise? Was it the DNM cable? Or the simple fact that my equipment shelf was resonating at a different frequency than usual, given the reduction of the mass on top of it?

Darned if I know. But even as my faith in the DNM's unique musicality, and the almost peerlessly high quality of the thing as a piece of electronic art, remains rooted in place, I'm even more curious than usual to see what John Atkinson's measurements uncover.

In engineering, the difference between being correct in one's convictions and being merely doctrinaire is the simple difference between making things that work or making things that don't. On the evidence of his latest preamplifier—as, I admit, with every other DNM product I've heard—Denis Morecroft is clearly on the better side of that fence. The 3D Six is simply amazing. Few amplification products are more beautiful, more effective, more fun to use, and, consequently, more recommendable.

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Footnote 2: I wonder if, on one level, the song is meant as a parable in which small, independent record labels—or publishing houses, or film studios—are seen as being less philanthropic than we enjoy thinking they are.