Analog Corner

Setup and Use: The Döhmann Helix 1 comes in a compact road case and is relatively easy to set up. It sits on adjustable leveling feet, from which the turntable itself is completely decoupled. It's big: 23.4" wide by 5.2" high by 18.7" deep. The MinusK suspension requires no tuning or tweaking, other than to adjust the vertical "travel" once the arm(s) has been installed: The suspension is very sensitive to weight.

Audio Union supplies a pair of thick, mirror-imaged aluminum armboards that can be machined to accommodate your choice of tonearm. The boards are bolted, from above, to suspended platforms. Once a board is in place, it can be leveled and/or raised to keep it from touching the frame below by adjusting two pairs of screws accessible from the top surface. In the front left corner of the chassis top are two illuminated pushbuttons: 33 1/3 and 45rpm, and On/Off (the latter glows red for Off, green for On).

The first time you screw down the record clamp, you'll think you've done something wrong. The suspension will bottom out with a bang, and/or the chassis will twist horizontally, making you think the whole thing is about to slide off the shelf. It won't. That's the MinusK platform behaving normally. You just have to get used to it, and modify your usual screw-down technique. Rubber stoppers or bumpers would prevent the knocking, but I wonder if they'd affect the 'table's tuning . . . ?

Schröder CB tonearm
Frank Schröder, the well-known German designer of tonearms, created his ingenious Captive Bearing (CB) arm for Audio Union. You can watch part of its assembly in the YouTube video mentioned above. (I was asked to edit out part of the procedure in order not to give away any secrets.)

The deceptively simple-looking CB arm, available separately from Audio Union for $4000, features a carbon-fiber armtube and offers nearly complete adjustment flexibility, though it lacks convenience features—such as on-the-fly adjustment of vertical tracking angle (VTA) and stylus rake angle (SRA)—found on some far more expensive arms. The CB uses ultralow-friction hybrid ceramic bearings that feature internal magnetic damping of horizontal motion. The antiskating is also applied magnetically.

The geometry is standard Rega: an effective length of 239.3mm, a pivot-to-spindle distance of 222mm—even the arm mount is the same as for the large, threaded pillars of Rega's older tonearms. The unbroken wiring, from cartridge clips to RCA jacks, is cryogenically treated, high-purity copper.

There's no arm lock because, the manual claims, they resonate—and will inevitably mar the armtube's finish. Nor is there a finger lift—if you're a fumbler, be careful! I won't go over the setup procedure, which is relatively straightforward but difficult to accomplish accurately, other than to commend the instructions for their clarity, completeness, and usefulness.

More useful is the manual's advice about vertical tracking force (VTF), especially the note about how the tightening of various screws affects the sound. The bottom half of the CB arm's two-piece, underslung counterweight can be screwed tightly to the upper half, the degree of tightness affecting the reproduction of the bass.

Measurements
When he set up the Döhmann Helix 1 and Schröder CB in my listening room, Dave Kleinbeck used Dr. Feickert Analogue's PlatterSpeed app (not really of lab quality, but still useful) and got a mean frequency of 3149.4Hz for the Feickert test record's 3150Hz. When, a few months later, I remeasured, I got 3150.5Hz (see fig.1). In that time the Helix 1's dynamic wow had risen slightly, from ±0.11% to ±0.17%. The low-pass–filtered relative maximum speed deviation went from ±0.01% to –0.03%/+0.02%, while the low-pass–filtered absolute maximum deviation went from –0.2Hz/+0.5Hz to –0.9Hz/+0.8Hz. These are exceptionally good, stable numbers.

Listening
The audible difference between a well-damped and a well-tuned turntable was apparent from the first record I played after having spent time with Acoustic Signature's Ascona Mk.2 turntable (footnote 4). Compared to the Döhmann Helix 1, the Ascona Mk.2 left the music in the box, sounding somewhat shut down and flat.

For my review of the Ascona I'd made a 24-bit/96kHz file of Ray Brown's Soular Energy (2 45rpm 200gm LPs, Concord Jazz/Analogue Productions APJ 45-268) and other albums, using the SAT arm, Lyra's Etna SL cartridge, and the Ypsilon VPS-100 Silver phono preamp—the only variable was the turntable.

I'm now playing files of that recording made with both turntables, and both sound very good—but the Helix lets the music erupt (as I wrote about the Caliburn 11 years ago), while the Ascona suppresses attacks and blunts sustains. The Helix allows both attacks and sustains to be fully expressed—from both Gene Harris's piano and, especially, Gerryck King's cymbals—while the Ascona Mk.2 blunts the shimmer and ring. This is what I heard directly from these turntables; having these files is really useful for corroboration—and mea culpas!

I could hear from the Ascona the same blunting of individual piano notes, especially notes higher on the keyboard; they were tamped down, instead of having a more generous, natural sustain and decay. The Helix 1's tunefulness—its harmonic and rhythmic correctness from top to bottom—was immediately obvious, as was the absence of any identifiable mechanical artifacts that could give its sound a specific character.

The Helix's smooth, liquid flow reminded me of VPI's similarly priced Direct Drive turntable, which says a great deal about what Audio Union has managed in a belt-driven design in terms of speed stability and, especially, musical drive. I could describe, say, its bottom end as "fast and clean," etc., but breaking the 'table's performance down into pieces would give short shrift to its top-to-bottom coherency—and, because of its exceptional image stability and solidity, would detract from the overall sound's easy believability and consequent relaxed listening pleasure.

After a more-than-satisfying month or so of listening to the Schröder CB arm with the Lyra Etna cartridge, through either the Ypsilon VPS-100 phono preamp with MC10L step-up transformer or CH Precision's P1 phono stage with optional power supply, it was time to change one of the variables by swapping the Schröder for the SAT arm—but not before recording more files.

With the SAT on the Döhmann Helix 1, two things became obvious: First was that the Schröder was a strong performer for $4000, or even more; and second, that the SAT on the Helix 1 put the Helix 1 and the Caliburn on a more level playing field. The SAT's superior bass performance was immediately obvious, but so was the Helix 1's ability to handle the SAT's explosiveness.

Also clear was that the Caliburn, overall, sounded slightly more laid-back than the Helix 1, which was somewhat more "present" and fast in terms of transient response. With "Exactly Like You," from Soular Energy, the Helix 1 produced sharper, more pleasing piano and bass attacks—but the Caliburn countered with richer textures in instrumental sustain and resulting harmonics.

I also digitized "All Roads to the River," from the reissue of Janis Ian's superb Breaking Silence (LP, Morgan Creek/Analogue Productions APP 027), mastered by the late Doug Sax, and I heard the same differences—which, through the Caliburn, produced a more fully fleshed-out reproduction of Ian's voice.

These are minor obsessive differences in the short term, and somewhat bigger ones long term—but so would be the Caliburn's almost four-times-higher price, were it still available. If I were offered a Helix 1 in exchange for the Caliburn plus cash for the difference in prices, I wouldn't do it—but I'd sure think about it!

Conclusions
I can't say that Audio Union's Döhmann Helix 1 is the equivalent of the Continuum Audio Caliburn, or that the Schröder CB performs as well as the Swedish Analog Technologies arm. But I'm not surprised that, overall, the two turntables, fitted with the same arm and cartridge, sounded more similar than different. The same chief designer oversaw both, keeping in mind the same carefully chosen goals.

More than a decade of thought and technological progress have allowed Mark Döhmann and another team of experts to find other ways to damp and tune, to house the motor outboard, and to avoid having to use an 86lb platter of cast magnesium alloy (which is costly and difficult to cast), or any number of other expensive tactics that can now, for the most part, be accomplished far less expensively (footnote 5).

Had I installed the Helix 1 in the same 2005 system that provided the context for the Continuum, I'd have written about it what I felt about the Caliburn: "no turntable in my experience comes close to its sonic performance and you are guaranteed to hear your favorite demo LPs, indeed all of your LPs, as you've never before heard them—I don't care what 'table you use or have heard."

Over the last decade or so, the best turntable designers have definitely upped their game, but I still think that, regardless of price, the Döhmann Helix 1 is at or near the top of the heap in terms of sound quality. What I said in the January 2006 issue about the Caliburn is equally true of the Helix 1: "What I marveled at most throughout the review period was not any particular sonic parameter in which the Caliburn performed well, but the unforced believability of almost everything I played, at whatever volume I played it."

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Footnote 4: See my review in the December 2016 "Analog Corner."

Footnote 5: Michael Fremer reviewed the Mk.2 version of the Helix 1 in April 2020.—Ed.