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Unsurpassed musicality. Inspired design makes the most difficult task appear simple   www.spiral-groove.com

As a medium for capturing music, vinyl remains unsurpassed. To convey its rich and nuanced potential, a turntable must, at the very least, achieve a high degree of control over the speed of its platter and the transfer of energy among its components. Noise is the nemesis, an uncompromised signal emerging from a silent background the goal.

"After reviewing quite a few cost-no-object analog rigs over the last few years, we’re absolutely smitten with this one...the SG-2 offers a HUGE sound for a relatively affordable price. It’s simple, beautiful and offers an exquisite level of fit and finish. We chose it as our Product of the Year in the analog category, and we recommend that you audition it before writing a check for one of those mega-buck contenders" Tone Audio

 

Turntable Art and Science

 

Vinyl remains unsurpassed for reproducing music. To convey vinyl's rich, nuanced potential, a turntable must have precise speed control and operate without producing mechanical or electronic noise. The goal is an un-compromised signal emerging from a silent background.

Noise Control

 

In the turntable body aluminum is the first-line of defense against errant vibration, storing and releasing energy in predictable ways. Assembled into a sandwich of differing thicknesses and separated by proven damping material, the result is a dense, stiff, and silent platform. The sound-absorbing, mechanically solid, yet isolated layers (i.e.: the motor, turntable bearing, arm-board, etc.) is found in SG1.2.

The platter is where the music begins. Spiral Groove's platter is belt-driven at the contact plane of the bearing to eliminate wobble or oscillation.  Spindle and bearing are decoupled yet precisely aligned. A thick phenolic layer forms the bulk of the spinning disc, topped by layers of vinyl and graphite. These materials act together to dissipate the energy generated by the stylus in the groove, all but eliminating the “stylus talk” common to most turntables. Threaded record clamps, made of stainless steel or anodized aluminum (depending on the model), snug the record to the graphite to create intimate contact for vibration transfer. Together, these features dramatically reduce the turntables' noise floor, giving unparalleled depth and specificity of image.

Stylus Talk

 

Pops and clicks on records occur when the stylus encounters a piece of debris in the groove and "plays" it as if it were part of the record. Such encounters also generate energy that, in some platters, is reflected back into the vinyl, moving the stylus and sending a second signal milliseconds after the first. This "echo" is so close in time that the pop or click is not heard as two pops, but as a louder and longer single event.

And, reflected waves don't only come from dust or dirt in the grooves. The movement of the stylus through the groove also sends energy into the record which, on insufficiently damped platters, comes back through the record to the stylus, causing a higher noise floor and coloring the sound.

Spiral Groove spares no effort to prevent mechanical-electrical feedback. SG platters are carefully engineered and constructed to dissipate energy. And they do: SG platters dissipate reflected energy so it can't get back to the stylus. Vinyl is a lot quieter and the music clearer when played on Spiral Groove.

Speed Control

All of our turntables use a 20 volt, AC synchronous motor driven by our proprietary outboard motor controller. The controller transforms AC wall current to DC and generates its own sine wave with switchable frequencies and adjustable phase to precisely control the motor. At startup the motor runs at full torque until it reaches speed when the current is reduced for smoother and quieter operation. The LED speed indicator flashes during start up, becoming steady when 33⅓ or 45 RPM is reached. Speeds are independently adjustable by 10% with 18-turn pots accessible on the turntable.

Please note: there is no further adjustment, calibration, or “tweaking” required to make the SG1.2 perform as designed. Once the table has been leveled and the speed checked for accuracy, it stays set up indefinitely. Get right to setting up the tone arm and cartridge (even these operations are easier and faster with Spiral Groove's Centroid tone arm) and enjoy a new level of reproduction from your favorite records.

 

RevolutionRevolution: Passion meets Performance

A serious 'entry-level' turntable for very high quality analog playback; the Spiral Groove Revolution incorporates sleek lines and bold colors in a “modern meets retro” package.

The SG Revolution is what happens when you blend just-the-right materials with uber-careful acoustics and electronic design.

The combination of materials and careful design are primary forces in the SG Revolution Turntable. Multiple layers of impedance matched material in the body, platter and feet, deliver an ideal playback environment for the LP.

The Revolution body is a sandwich of aluminum and delrin. This rigid platform creates a tightly coupled yet isolated connection between platter and tone arm. Its aluminum platter, with varied interior and exterior angles, is topped with a delrin record surface to create an isolated energy sink for stylus-induced vibrations. A low voltage AC synchronous motor and highly evolved motor control system assure constant speed and minimum noise. Graphite, aluminum, and engineered elastomer, in the height-adjustable feet provide excellent isolation from external disturbances.

This carefully orchestrated combination of high mass, extreme solidity, superior speed stability and non-existent noise floor, converge in the Spiral Groove Revolution to deliver the cutting edge of LP playback.

  • Weight - 78 lbs. excluding tonearm and power supply
  • Size - 20” W x 15” D x 7” H
  • Body - Aluminum and delrin sandwich
  • Platter - Aluminum with delrin record surface
  • Platter bearing - Hardened steel low profile inverted bearing with sapphire thrust plate.
  • Feet - Graphite, aluminum and elastomer - height adjustable
  • Motor - AC synchronous
  • Power supply - AC sine wave generator and amplifier. Phase corrected and frequency adjustable.
  • Speeds - 33 - 45 rpm, adjustable
  • Removable arm board
  • Magnetic weight reduction system in platter
  • Guarantee - 10 years mechanical, 3 years electrical

SG1.2

Spiral Groove SG 1.2

The SG1.2 body is comprised of four aluminum layers in two independent constrained-layer platforms. These two mirror-imaged assemblies, separated by four carefully positioned elastomers, function as a single platform. The feet, with Strange Attractor technology and low frequency damping, are attached only to the bottom layer. The second layer, which is separated by rigid damping material, provides a stable platform for the motor. The upper half of the SG 1.2 body isolates the platter and tonearm in a similar fashion. The bearing/platter assembly attach to the 3rd plate from the bottom. The top plate, which is separated by a rigid damping layer, provides the tonearm mount. This allows motor, platter, arm, and the furniture the turntable rests on, to remain isolated from each others' vibrations while maintaining critical alignment between them.

The unique Spiral Groove bearing is made from the same case hardened steel used for an F1 racing car's crankshaft. Utilizing material made for high heat, high speed, high wear applications might seem unnecessary for a turntable bearing, but, it's actually ideal for several reasons. For one, it allows us to machine an extremely small bearing gap for superior platter stability. Secondly, since both bearing components are made from the same material, the clearance between bearing parts remains unchanged by temperature variations. In bearings made with dissimilar materials, varying rates of expansion and contraction result in variations in the stability of the platter. This can’t be controlled unless a heater is used to stabilize the temperature. Our bearing design assures consistent high level performance without complicated compensation systems. And the steel we use is so durable that we confidently offer a 20 year warranty.

The Spiral Groove bearing incorporates a steel ball and sapphire thrust plate so the entire weight of the platter rests on the very small contact area between the ball and sapphire. This spot is vulnerable to wear and is a source of noise. To further insure the bearings durability and smooth operation we use a custom designed magnet system that reduces the weight on the sapphire to about 2 Lbs. This is a major contributor to its smooth operation and low noise.

Like Strange Attractors, the SG1.2 platter is built with irregular shapes and carefully chosen materials. The Graphite and Aluminum assembly provides a non-resonant surface for the record to mate to. Energy transfers quickly from the record through the platter and is dissipated internally. A 14 inch stainless steel drive ring provides the inertia of a much heavier platter. The speed stability it provides can be heard in the SG1.2's rock solid sound stage. Our simple and reliable clamp assures close contact between the record and platter surface and helps flatten warped records.

Our arm board has a lovely twist, so to speak: the SG1.2 arm board is fitted with a stainless steel bayonet mount. With the push of a button and a slight twist like a camera lens, it is easily removed from the turntable. This unique system provides the enthusiast fast and easy arm-and-cartridge swaps with accurate re-attachment. Once a cartridge and arm are set up and adjusted, detachment and re-attachment with the bayonet mount provides solid, locked-in, perfect alignment every time.

The extremely low residual noise floor of the SG1.2 reveals not just nuance, but sheer clarity. It breathes both low level and high level dynamics more convincingly. With very controlled authority it reveals low frequency extension and drive that is felt as well as heard. The SG1.2 exudes an authoritative calm that is a window into the soul of the performers. By removing itself from the equation it lets the vinyl—and only the vinyl—do the talking.

SG 1.2 Features and Specifications

  • Oversized stainless steel platter drive ring for increased inertia and speed stability
  • Inverted sapphire disc/hardened steel polished ball bearing for silent, long wear
  • Platter driven at rotational plane of bearing for wobble-free rotation
  • Spindle de-coupled from bearing for optimal mechanical isolation of record
  • Magnetic levitation system to reduce platter weight on the sapphire thrust bearing
  • Graphite and aluminum platter
  • Low durometer round belt
  • Quick-change bayonet mounted arm board
  • Electronically selectable speed control with fine adjustment: 33⅓ & 45 rpm
  • Low voltage/high torque AC synchronous motor with proprietary phase control to eliminate cogging.
  • Adjustable, decoupled, aluminum and graphite feet
  • Dimensions: 18.5” W x 15” D x 4.5” H
  • Weight: approximately 80 lbs.

Centroid TonearmStructural rigidity and the efficient dissipation of unwanted mechanical energy are hallmarks of the Spiral Groove tonearm. Three criteria have determined the choice of tonearm materials: low mass, high strength, and the ability to transfer energy quickly away from the cartridge. Moreover, in order to give that energy somewhere to go, SG has established a direct link between cartridge & mechanical ground.

No other tonearm available today dispenses with wayward energy more efficiently or effectively.

Optimal rigidity and the exceptionally fast transfer of energy from headshell to ground are just two of the reasons the Centroid tonearm delivers unsurpassed speed, dynamic energy and tonal purity. Another is its overall balance. Unlike most other tonearm designs Spiral Groove use advanced computer modelling to simulate the forces exerted on the arm as the cartridge tracks the record. Understanding these forces dynamically has enabled SG to compensate for them mechanically. This approach is called 'Balanced Force Design' (see below), and with it’s principles they have greatly improved tracking & optimized the performance possible from any cartridge.

In order to deliver their best performance, high-end cartridges require tonearms that facilitate precise alignment. On the Centroid tonearm the Overhang, VTA, Azimuth, Zenith, Anti-skate control and tracking force are all easily & precisely adjustable. Spiral Groove, in addition, supply a proprietary mirror setup gauge to enhance the performance of any manufacturers cartridge, as well as ease the set-up of the arm.

The Spiral Groove tonearm was designed not only to set new engineering standards but also to please the user. Like the turntables themselves the tonearm is exceedingly user friendly. Originally the Centroid was conceived to make a perfect marriage with the Spiral Groove turntables, but in their wisdom SG have also designed a version of the Centroid arm with a Universal fitting arrangement, thus allowing all vinyl users access to Spiral Groove’s ground breaking performance – irrespective of the choice of table used.

As with all of Spiral Groove’s products the Centroid is simply a “servant to the music”.

TECHNICAL SPECIFICATIONS
Balanced Force Design™ - modal analysis places centroid at bearing point
Counter-weight design minimizes moment of inertia by staying close to bearing
10" pivot-to-stylus distance
Swiss made sapphire bearing cup and steel pin
“Zero tolerance” unipivot bearing design
Multi-layered, damped arm tube
Low mass, high strength aluminum/carbon fiber arm tube
High purity copper internal wiring
Overhang, VTA, Azimuth, Zenith, Anti-skate & Tracking force all easily adjustable
Precise mirror set-up gauge included

Balanced Force Design is at the heart of Spiral Groove and the basis for all products we manufacture. Indeed, it is one of our most important “assets”. The result of our design method is product homeostasis, where sheer performance, manufacturability, intuitive interaction, durability, and beauty exist in balance. Balanced Force Design is elemental and simply described, however the implementation is far from easy.

The first seemingly obvious goal is to establish, in fundamental terms, the function of the item being developed. i.e. a rotating platter at a constant 331/3 RPM. The next goal is to identify anything that would compromise or impede functionality. A constantly rotating platter is but one operation within the matrix of operations in an active turntable. Identifying and understanding the inter-related dynamics of all its parts is a much bigger and more complex task.

Finally, the most difficult goal is balancing the solutions while not creating new problems in the process. When accomplished, the result is a naturally elegant product that provides a level of performance, service life, and ease of use far beyond it’s seemingly simple form.