Helix 1 Turntable
Mark Döhmann – Systems Architect – Helix 1 Each form of media, digital or analog, is a facsimile of the original performance. No media is truly inclusive of every detail of the performance, however, are we extracting all the available information from the media? Mark Döhmann has proven yet again we are not!
The Döhmann Helix 1 delivers unparalleled analog playback performance due to its unique Micro Signal Architecture© (MSA) engineering that sets new noise reduction and micro-signal preservation benchmarks.
MSA is a cohesive approach to design that uses the most advanced techniques available to remove physical and mechanical vibration and electrical noise. This approach to signal preservation is the brainchild of Mark Döhmann, who has conquered the seemingly insurmountable obstacles frustrating turntable designers since the 1950’s.
Mark is respected among his peers for original thinking and an understanding of a turntable’s architecture and which elements influence psychoacoustics (how our brains perceive music and sounds).
By joining forces with a team of talented scientists, engineers and designers, Mark has addressed each aspect of noise and vibration suppression utilizing the latest in visualization techniques, engineering concepts and patented technologies.
HELIX 1 ARCHITECTURE Helix 1 rewards the listener with the closest facsimile to master tape yet realized. How do we know this?
Our engineering facilities and listening rooms use several studio reference level and highly modified master tape systems to compare the Helix 1 along with a range of other well-known turntables.
The specifications of the Helix 1 demand the ultimate in noise suppression and isolation systems to allow the turntable and pickup arms to deliver the micro-signals buried in the vinyl grooves on well authored LP’s.
Every aspect of the turntable design requires the preservation of the micro signals found in the groove of the LP to be retrieved with as little modification and distortion as physically and electronically possible.
Döhmann Helix 1 by Audio Union table incorporates several engineering advances to deliver the lowest resonance profile for any pickup arm and LP combination.
•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).
You will have to judge for yourself, how close we have come to the gold standard.
Audio Union dealers and owners are convinced there is no peer in analog LP playback.
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 prestress 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.
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 behavior 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 Visualization Techniques
By creating a visualization 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:
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 layman’s 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.
Special features include an EDR – Edge Damping Ring which damps the platter and LP edge and a damping mat to interface to the LP.
Arm Board Assemblies
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 owners manual that includes step-by-step directions for set up although we recommend working with your authorized dealer.
The table is very easy to set up, use and play.
System Components The Helix 1 system comprises a turntable with its internal suspension system using a unique Negative Stiffness Mechanism (NSM) isolation technology and integrated motor using twin belt drive for speed accuracy.
Turntable All controls for normal 33 or 45 operation are located on the turntable top panel.
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.
The current bearing design allows for vacuum hold down and the Control Box has been specified to allow for fitment of a vacuum module. This will be field tech upgradeable when released.
The turntable comes with separate power supply and servo control box which is connected by two custom cables to the turntable chassis.
The turntable is designed to be mounted on a wide variety of surfaces as it has an intrinsic suspension system fully integrated with the chassis.
The specification includes the ability for the turntable to work in older style buildings and domestic locations where wooden floors and building movement create instability and issues such as feedback and footfall interference. The Helix 1 is isolated from these issues.
Dimensions and Weight
Helix 1 - Table Width 600mm (24”) x Depth 480mm (19”) x Height 250mm (10”)
Helix 1 – Control Box Width 483mm (19”) x Depth 480mm (19”) x Height 133mm (5”) Standard 3RU (19 inches) Configuration.
Power 120 VAC, 50/60Hz 2 amps or 220/240 VAC, 50/60 Hz 1 amp
Combined shipping weight is 80Kg (shipped in 2 custom fabricated boxes).
Recommended installation requires a surface capable of supporting up to 80Kg (160 pounds) and a 620mm (25”) wide x 500mm (20”) deep surface for the isolation platform to be able to move freely.
Factory set speed selection by push button for 33 1/3 or 45 rpm.
The Helix 1 allows 33, 45 and if required 78RPM and a wide variety of engineering adjustments to create “audio bliss” that is very user friendly and easy to operate.
Multiple arms up to 12 inch are accommodated with ease of operation and setup assured. Removable arm boards allow simple interchange and calibration.
Note: Set-up assistance and complete service available worldwide through authorised dealer and representative network.
Helix 1 turntable - by Mark Dohmann and Audio Union
Helix 1 turntable by Mark Dohmann with Schroder CB tonearm, demand the ultimate in noise suppression and isolation systems to allow the turntable and pickup arms to deliver the micro-signals buried in the vinyl grooves on well authored LP’s.