DÖHMANN, “the frontier of Vinyl”

Mark Döhmann has an impressive CV as a turntable designer that stretches back to 1982. You may know him from the £120,000 Continuum Caliburn which he designed around 10 years ago now. That particular deck set the industry alight at the time and offered a new perfomance benchmark for Vinyl reproduction arguably not seen since the days of the big Rockport turntables and the Micro Seiki 8000II.

In 2010 Mark left the industry to pursue some software development projects in bionic engineering but sometime in 2014, under the stewardship of Rumen Artaski of the Audio Union company, he was enlisted to spearhead a new statement turntable project, accompanied by other key leaders in their fields of expertise, notably Tonearm designer Frank Schröder, Allen Perkins designer of the multi award winning Spiral Groove SG1 turntable bearing and Dr. David Platus, founder of Minus K technologies, world leaders in the field of vibration isolation for applications as diverse as Microscopy, Spacecraft ground testing and Neuroscience.

The result of this collaboration of some of the best minds in their respective industries is the Helix 1 turntable. Reflecting the illustrious multi-disciplined team who developed the Helix, this product is an ingenious amalgamation of various complex technologies all designed to bring about the highest benchmark in noise suppression and isolation. Audio Union believe that the Helix 1 delivers the lowest resonance profile for any pickup arm and LP combination and sets a new standard in fidelity to master tape and reduction of background noise.

Following on from the dual arm Helix 1, the team set about offering the deck in a more real estate friendly package and at a substantially lower cost. Whilst the 1 offers superb value for money relative to the marketplace and other ‘super-decks’ against which it was benchmarked and developed, the compact footprint, single-tonearm Helix 2 is now offered at a substantially lower cost with a minimal drop in performance.

Features include

MSA – Micro Signal Architecture©
NSM – Negative Stiffness Mechanism Vibration Isolation
0.5 Hz (Fz) Vertical 1.5 Hz (Fz) Horizontal
MCT – Mechanical Crossover Technology
TMP – Tri-Modal Platter system
EDR – Edge Damping Ring
TDS – Tone arm Damping System
RTS – Resonance Tuned Suspension
DLC – Diamond Like Coating Amorphous Material Bearing Friction Modifier
HTAD – High Torque Adjustable Drive Speed Selections 33, 45 RPM (78 RPM by request)
Velocity Adjustment Lock – Speed is constantly calibrated over 130,000 times per second to deliver precise 33.33 or 45.15 rpm (factory default).

MICRO SIGNAL ARCHITECTURE (MSA)©

Micro Signal Architecture© (MSA) is a cohesive design approach that uses the most advanced available techniques to remove physical and mechanical vibration and electrical noise.

Entering the world of microscopic endeavors there are barriers; for example, the actual method of measurement can deflect the measurement itself. Thought is needed for the measurement system to deliver the best result. For example, numerous research facilities around the globe have millions of dollars invested in microscope systems examining atomic scale objects to enhance our understanding of the physical world.

Images at the nanoscale are extremely sensitive to external vibration even under vacuum. Experiments utilizing sensitive equipment such as; Atomic Force Microscopes, Electron Microscopes and laser scanning systems, require the staff to stand still in the building and machinery to be disabled, when a sensitive image is captured by the microscope. Similar to Hollywood movies of submarine warfare!

In actuality, even foot steps several floors above can transmit through concrete structures and blur the images. This is not an elegant solution for such expensive research, only with the installation of advanced vibration suppression and isolation can the images be retrieved in fine enough detail to show new insights. So how analogous is this to audio?

For analog systems such as the audiophile turntable it is extremely relevant to the performance of the table. For vinyl playback, the enemy of any signal found in the mechanical groove by stylus tracing is also vibration and electrical interference!

Many audiophiles and music lovers lament the lack of isolation on turntables, from entry level to cost-no-object designs. Existing turntable suspension and isolation systems may not achieve the real world performance objectives they claim and listeners experience feedback, information blurring and over-weighted boomy bass response. Modern homes, are not designed for vibration control. In older homes with wooden floors these systems become unstable and do not stop footfall or feedback loops occurring (the classic tiptoe around the suspended turntable else your cartridge mistracks syndrome). This is predominantly due to the natural frequency of these suspension systems not being low enough (0.3hz-1.5hz).

The innovation in Helix 1 lies in the ingenious way the NSM isolation technology is integrated. The turntable and NSM device form a fully acoustic and mechanically balanced system. The result is a precisely designed “mechanical crossover” that harmonizes the forces at play between the incoming external acoustic and mechanical vibrations (the environment) and the self-generated internal vibrations caused by bearings, motor and chassis dynamics (the hardware).

By complex use of recent developments in software measurement technology for Chladni plate analysis and engineering “cymatics”, the team at Audio Union has developed a complex chassis system that effectively damps vibration utilizing a semi-active topology.

The Helix 1 showcases the use of semi-active vibration suppression in a pre-stress accumulation/release (PAR) design. This is a method to convert the strain energy of a vibrating system into kinetic energy, which is then released from the system by means of a dissipative device. This delivers superior isolation to the level demanded by the most sensitive electron microscopes and atomic force microscopes.

The design is semi-active; it does not require adding any substantial amount of energy, is highly efficient and cost effective compared to an active system. Active systems have a tendency to add noise to the operating environment, this is also undesirable. Our approach eliminates this unwanted noise that can disrupt the stylus to record interface.

 

Mechanical Crossovers

One of the major influences in the sound reproduction of vinyl play back is mechanical vibration. After all, turntables are mechanical devices. What if a “mechanical crossover” concept could be extended to create a smooth continuous pathway to channel vibrations away from critical areas on a turntable?

Historically mechanical crossovers have been well documented in loudspeaker design for decades. Experienced designers such as Dr Plamen Ivanov Valtchev in Europe have published numerous papers (AES, patents, etc.) on advanced mechanical speaker structures and designs.

Here is a summary of one successful implementation.
Coupling the cone of the speaker to a voice coil bobbin through a compliant section and directly attaching a small lightweight whizzer cone allows the compliant section to serve as a filter! The main cone is not vibrated at higher frequencies as whizzer cone responds to all frequencies, however due to its smaller size; it limits the output at higher frequencies, thereby implementing a “mechanical crossover function”.
From this method we learn the shape and weight of the components influence acoustic behaviour under vibration. Therefore, selection of materials and the suspension elements used determines the crossover frequency and effectiveness!

By extending the mechanical crossover concept to the Helix 1, physical zones can be defined on the infrastructure that focused vibrations away from key areas (platter, bearing, motor, tonearms, floor modes), establishing a smooth continuous pathway to channel vibrations away from critical areas on the turntable!

The Helix 1 has been designed to reject low frequency vibrations coming up from the floor by using the MinusK NSM isolation system and drive higher order vibrations generated through motor noise away from the bearing and platter via a complex coupling to the chassis. For these higher order vibrations local isolation, absorbing, redirecting and suppression technologies are employed including semi-active decoupling from motor vibration.

The Helix 1 is designed to operate flawlessly in non-ideal environments suffering from floor borne vibrations such as older houses with wooden floors, upper floors, attics and any external vibrations which are carried through buildings – even those made from concrete steel, and brick.

 

Measurement and Visualisation Techniques

By creating a visualisation technique to see these vibrations in real life, the team can see where the vibrations “collected” on a chassis under real life operating conditions.

Chladni Plate Analysis

Extensive use of Chladni plate analysis and the subsequent use of pre-stress in the chassis design allowed the positioning of “anti” vibration zones in critical areas (Motor, bearing and arms) vs trying to damp it with one solo material or less effective broadbrush approaches.

Our experimentation confirmed no “magic bullet” exist for resolving the challenges facing existing turntable designs. It is the precise blending of high-tech materials and topologies which has created the sonic breakthroughs in the Helix 1. Vibration analysis has advanced since the pioneering work of Robert Hooke in 1680 and Ernst Chladni in late 1700’s. Chladni’s Law F=C(m+2n)p can be used in complex eigenmode and wave analysis of turntable chassis. The Chladni method is used by artisans and scientists alike in the creation of musical instruments and engineering solutions.

In simpler terms, “the bearing is the center of the “universe” where “planets” (Motors and Arms) sit on an orbital plane (the chassis/plinth). Vibrate the plane (chassis/plinth) by internal or external means and you get vibration patterns and nodes which become visible to the naked eye using Chladni plate analysis.

By placing the bearing and motor and arms into “optimal zones” where vibration was well damped or controlled we provided the best possible place on the chassis for the susb-system to sit with the lowest possible vibration. Helix 1 chassis research created several eureka moments!

Some resources can be viewed here:
History of Chladni’s Law
Chladni Plate
Music + Math: Chladni Plates

 

Motion Control

Helix 1 design is a significant enhancement on state of the art and its motion control defines what will become part of a new breed of “super turntables”.

HTAD – High Torque Adjustable Drive. This is where torque curves and “ballistics” can be adjusted by “musicians and artisans” to “voice” the table for ultimate performance and musicality. This software driven perspective unveils a unique capability for system designers to work with every aspect of a drives performance and open new vistas into music performance.

The precision motor industry is changing rapidly to embracing a software driven architecture. Helix 1 technology is taken from latest developments in sub micron servo drive systems for precision optics and adapted by our engineering team to deliver superior motion control to the Helix 1.

The Helix 1 motor control system is a digital closed loop servo with greater than 16bit resolution. Absolute positioning reading occurs over 120,000 discrete positions of the rotor per revolution. The motor spins several hundred times to achieve one revolution of the platter thus increasing the system resolution by an order of magnitude over a direct drive topology.

In laymans terms; this means at 33/45 rpm platter speeds we have an incredibly high number of checks on the speed stability per second. This information is fed to a super fast microprocessor in the servo control and our custom written software then defines the stiffness and the ballistics of the system and responsiveness of the servo loop. Different ballistics (inertia/force ratios) can be programmed to yield different sonic signatures and sound dynamics. Using a laptop interface we can tune sonics of the drive and control a comprehensive set of variables.

The table can act like a high torque Direct drive or like an underpowered low torque design depending on servo programming. Torque force can be adjusted to suit sonic palettes and the frequency of the drive shifted to areas that are better handled by the mechanical design and vibration control.

Cogging is prevented by a proprietary coil design that smooths the motor to vanishing low levels of vibration. Our motor design team has delivered extremely low motor noise on the Helix 1. We have not found any comparable system able to attain similar results.

The speed is factory set for 33 and 45 and does not need adjustment in normal operation. However if a user wishes to adjust the reference speed a software application via a smartphone/tablet/computer allows adjustment. It is also able to be securely connected to our service technicians for diagnostics and firmware / software upgrades.

Advanced settings are provided to factory trained technicians via stored named reference files for clients custom installations.

 

Plinth

The 120mm (four-inch) plinth is made from precision CNC aircraft grade aluminum and structural alloys and weighs close to 50 kg (100Lbs) when assembled. Connected by a series of interlocking plates which are fitted closely to the MinusK suspension system and allow for the mounting of the sub-systems such as motor, bearing, tonearm combinations. A laminated glass plate is used to add ballast and lower the center-of-mass. This glass plate provides visual access to the MinusK suspension for performance monitoring.

 

Platter

The 15Kg (30Lb) platter is made of triple layer of an engineered thermoplastic (made for Audio Union by a European supplier of polymers), and non-ferrous alloy machined to close tolerances. Each high-mass platter is balanced and shaped for lead-in groove and record label.

Special features include an EDR – Edge Damping Ring which damps the platter and LP edge and a damping mat to interface to the LP.

 

Spindle/Spindle Housing

High reliability and ultra low-noise operation were specified as part of the architecture. Audio Union engineer Stanislav Stoyanov developed a new low height, high stability custom bearing design for the Helix 1 using MARAGING STEEL to provide the desired capabilities, precision and low thermal and flex modulus. A single, ceramic ball, located at the bottom of the spindle is used for trouble-free operation on a quiet thrustpad. The high tech lubrication system is sourced from the aeronautical engineering field to ensure low noise operation.

 

Record Clamp

The record clamp is designed for ease of operation and secures the LP effectively on the platter surface and flattens even severe warps in poor quality LP’s. The clamp is a multi-piece design which has a reduced damage profile in the event a user accidentally drops the clamp onto an LP during operation. This was designed for “real-world” use (late night LP sessions and low lighting where operator fatigue sometimes occurs).

 

Motor

A precision single spindle high-torque motor featuring zero cogging is used. The motor can supply up to 100 watts of power for the most demanding control needs. By careful software controlled ballistics the belt system is gently started and bought to rest to avoid premature wear. Speeds are factory set and rock solid.

 

Belt

Dual high damping o-ring belts are provided for stable drive transmission.

 

Arm Board Assemblies

The Helix 1 supplies two armboards (for dual arms) that are removable and can be predrilled for most commercially available arms or left blank for future use. The armboards are able to be fitted or removed externally with arms mounted. No need to dismantle and recalibrate. The chassis has a damped tubular cross-section underneath which precisely locates the armboards relative to the bearing and platter. This provides a very rigid system with minimal flex and movement.

 

Tonearms

The Helix 1 is able to function with your choice of arm. We recommend the Schröder CB Arm which has been custom designed to work seamlessly with the Helix 1 and delivers exceptional performance.

 

SET UP

The Helix 1 turntable can be mounted on normal non-audio grade furniture (as the suspension system will work independently) and fit in with any architecture and decore.

Any platform the turntable sits needs to support 70Kg (140 pounds) and is at least 620mm wide and 500 mm deep.

Helix 1 includes an owner’s manual that includes step-by-step directions for set up although we recommend working with your authorised dealer.

The table is very easy to set up, use and play.

 

System Components

Turntable

All controls for normal 33 or 45 operation are located on the turntable top panel.

Control Box

A separate “control box” motion control servo drive is located in separate 3RU standard rack size housing which can be placed conveniently nearby or out of sight.

The unit comes pre-calibrated to precise speed for 33 and 45 from factory. The drive system monitors the speed constantly over 130,000 times per revolution to deliver direct drive like accuracy without speed drift. Speed adjustment is accessed via simple USB interface on the Control box and can be done remotely or onsite using a simple GUI connected to the USB direct or via secure Wifi.

Version shown here is anodized silver/black halftone edition. Unit is available in all black and all silver anodized configurations.

Mark Döhmann – Systems Architect

Mark is recognized for continuously developing analog systems having been a staunch advocate of the core technology since the early 1980’s. He has a well-respected track record in innovation and design of advanced turntables and tonearms of the highest caliber since 1982. He generates original ideas and understands the influence these innovations have on the sonic result.

In 2012 Mark experienced firsthand the use of Chladni plate analysis in the creation of bespoke stringed instruments by a world-renowned luthier. Mark was impressed by the luthier’s mastery of his art and recognized the potential for the same techniques to be used in deriving the sonic attributes of a turntable. This “eureka” moment opened a whole new panorama of creativity and new tools for turntable design.

Mark originated the tight integration of NSM technology into the Helix 1 design with Dr David Platus from MinusK. The engineering team constructs each mechanism from exacting specifications needed for the Mechanical Crossover to function as designed. The end result is a customized NSM system capable of consistent laboratory grade integration of the technology into every table we manufacture.

 

Rumen Artarski – Executive Director of Engineering and Marketing

Rumen aka “Cesar”, the Director of Engineering, has well established international credentials in the audio and video industry. His journey started with an Electrical Engineering degree from University of Denmark before working in UK (London) in several high end recording studios as an engineer and studio designer. As a successful entrepreneur in many industries; including clients in aerospace, defense, and big budget film and television it was only natural for Rumen to return his focus to his true passion for music.

Rumen is the key integrator and facilitator of the engineering team used for the integration and application of the “mechanical crossover” and Micro Signal Architecture© directives. His collaborative efforts successfully incorporated the subassemblies, motion control systems and drive technologies; all possible noise sources that exceeded the MSA specification. His patience, knowledge, effective communication skills and commitment to our customers is the key factor in the successful development of the Helix 1.

 

Frank Schröder – Analog Designer

Frank is one of the most respected analog designers of his generation and one of the industry’s true gentlemen. His immense knowledge of audio history of the audio art provides insight into the genesis of ideas and who they should be rightly attributed to. He has designed several impressive analog systems in his own right and his tonearms are among the most sought after in the market. He holds patents for his technologies and is a regular visitor to Audio Union’s main European manufacturing hub.

The CB tonearm is generating industry discussions as being one of the finest tracking arms ever made. The bearing system offers lower friction numbers lower than even the venerated Technics EPA-100. Sonically, the CB it is a musical masterpiece.

His contributions to the Helix project include advanced magnetic pre-loading systems and the ingenious arm bearing design. The Helix 1 is evidence of Audio Union’s ability to collaborate effectively to attain our lofty goal, restoration of “High Fidelity”.

 

Lee Gray – Industrial Designer

Lee is one of the rising stars in the Audio engineering community having penned several award winning industrial designs. The look of the Helix 1 table is a testament to his abilities, aesthetics and integration skills. He is part of the Audio-Union consulting team.

 

Allen Perkins – Bearing Design

The bearing system in a turntable is a critical part of the interface between the chassis and the platter. Great bearing designs are recognized for their ultra quiet operation, lack of precession and superb stability. Allen Perkins is one of the gentlemen of the industry and accepted globally as an innovator and builder of quality turntables in his own right. The bearing technology used in his SG1 turntable received critical acclaim for its ultra low noise operation. This key attribute was one reason Mark reached out to Allen to assist him on the original prototypes of the Helix One turntable. This early collaboration with Allen led to further bearing development in Europe to match the production needs of the Helix system. The Helix One bearing system maintains precession at vanishingly low levels and delivers ultra low running noise to meet the MSA specification. Fully manufactured in Europe with CMM and Quality Assurance systems ensuring all parts hold the precision tolerances required to match the unique platter system of the Helix One.

 

Bo Christensen– Industrial Designer

Bo is one of the most acclaimed creative designers in the Audio industry having penned several award winning iconic designs with Primare and Bow Technologies as well as other commercial brands. Bo was part of the genesis of the Audio Union team and provides his considerable master skills to guide the aesthetic values.

 

Stanislav Stoyanov – Mechanical Engineering

Stanislav is a graduate of the European and Russian Aeronautical engineering schools and holds qualifications in advanced engineering disciplines, science and advanced metallurgy. He heads up the mechanical engineering team at Rumen’s facility and oversees the many millions of dollars of CNC and surface finishing technology. He continues to work on commercial aeronautical projects for Lufthansa Technik. This means the Audio Union products are able to access the best systems for quality manufacture and repeatability. Full CMM and Quality Assurance systems ensure parts are built to best practice.

 

Dr. Plamen Ivanov Valtchev – Engineering Consultant

Plamen is a senior technology contributor to Audio Union and the Helix project. He is an expert in the use of advanced software visualization, FEA modelling and acoustics. In a jointly owned facility with Rumen Artarski our CEO, Audio Union has access to the most advanced test and measurement equipment. Plamen developed new software driven tools for the Chladni plate analysis methodology and also worked on the physical test models.

 

Dr David Platus – Vibration specialist and Founder of MinusK

David is one of the most respected designers in the field of vibration isolation and holds numerous patents in the field. A close association with Dr Platus led to the design of a new custom low frequency isolation system for the Helix 1 table. This technology is a world first for a turntable project.

 


Thomas Kleinbeck – Mechanical Engineering

Tom is one of the guiding forces behind the EnKlein Systems company and hails from Kansas City MO. He is a senior mechanical engineer and advanced fabrication specialist. He holds numerous patents for engineering innovations and aeronautical technology. Everyday people travel safely whilst relying on some of Tom’s inventions. Tom was highly trained by the US government in technology during his tenure in the armed services and this broad experience means the Helix 1 is built to most exacting standards and achieves high reliability. Tom works closely with Mark to ensure the conceptual world is translated into reality. He provides engineering services to the European team at Audio Union and coverage to our Support team in USA and Asia/PAC.

 

David Kleinbeck – Director Audio Union International

David is the founding member of EnKlein Systems and also hails from Kansas City MO. David is one of the world’s leading RF/EMI/Transmission engineering consultants. He holds a BSECE, Electrical, Electronics and Communications Engineering from University of Missouri-Columbia. David has worked for several US Government agencies in various technical capacities before joining the commercial sector with Fluor Daniel, Nortel Networks, Sprint and most recently K&M Systems as VP Research and Development. He holds several patents and is regularly consulted by global telecommunications companies for technology initiatives.

David provided the electronic and RF shielding topology for the Helix 1 to ensure the Micro Signal Architecture© extended across the electrical and RF spectrum.

David also heads up Audio Union International the USA based Head Office and provides technical, business and corporate governance to the business to allow our USA customers access to quality business support and services.

Further Reading
The sound the Helix 1 was producing was incredibly compelling, engaging and supremely musical. The level of detail and nuance to the sound, the deep, authoritative bass and immense sound-stage scaling made available through the SAT arm and Lyra pick up were deeply involving. I’d be hard pressed to list another turntable that was as capable as the Helix 1 in producing such an absolutely black, dead-silent background for the music to leap from.
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.”
Fremer, Stereophile
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.”
Michael Fremer, Stereophile
“we dropped the needle and I knew instantly, that it was the quiestest turntable I’ve ever heard. What this turntable delivers sonically is stunning.”
Peter Breuninger, AVShowrooms