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.
Spiral Groove builds two turntable models, identical in design concept using decoupled mass, purpose specific materials, and precisely designed construction to eliminate noise and give precise speed control for ideal playback.
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.) are found in both the SG2 and SG1.1.
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. Both the SG2 and SG1.1 platters utilize a 14 inch drive ring of either aluminum or stainless steel to guarantee exceptional speed stability. 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.
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.
All of our turntables use a 12 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 either the SG2 or SG1.1 perform as designed. Once the tables have been leveled and the speed checked for accuracy, they stay 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.