May 2009. Munich High-End Show. Thorens is delighted to announce that the results of over 18 months of research and development have come to fruition in the shape of the new Thorens TD 309 Tri-Balance turntable. The TD 309 will be available from September 2009 in a choice of Black or Red. Estimated retail price Euro 1000 – 1200.
Summary
• New innovative Tri-Balance suspended sub chassis turntable
• New suspension system to make setting up easy
• New Team in design and marketing
• Design brief: Performance, Performance, Ease of setting up, Design etc
• Low Noise, Low Voltage electronically speed controlled DC Motor for best performance
• Adjustable belt tension for best performance
• Aluminium sub platter with single line contact
• Fused silica platter for consistency and sound quality
• New low resonance TP92 arm with precision Japanese bearings
• Arm adjustable for azimuth and overhang.
The Background
The story began with Heinz Rohrer the CEO of Thorens making the decision that the time was right to move from the ‘stabilise and grow’ strategy of the past few years to the ‘invest to re-establish position’ strategy. Heinz had always planned Thorens as a three-term strategy. ‘Recovery and survival’ when he first took over Thorens, then ‘stabilise’, and now ‘investment to re-establish pre-eminent position’.
Of course, the way to create the products to reposition Thorens was key. Advice was sought from many areas. Advice was considered and a radical decision was taken. If Thorens was to develop innovative, performance orientated products it needed a very wide combination of skills that could not come from one person. It had to be a team. The choice of team in some ways was easy. Heinz had already worked with Helmut Thiele on some industrial design projects. Helmut was both a colleague and an old friend of Karl-Heinz Fink. For electronic engineering, the obvious choice was the brilliant Walter Fuchs who worked with Karl-Heinz on some projects. That left product planning and marketing. Karl-Heinz suggested Steve Harris to get a more international team and Heinz agreed after meetings in London and Basel. The team formed. Some with turntable design experience, some not; but they came with the benefit of open minds.
The Brief
The brief was simple: remember the past if possible but do not let that stop you designing something brilliant. The target customer was a music lover but not necessarily a total audiophile. At the same time, audiophiles should also feel comfortable with the turntable. The primary goal was performance, the secondary goal was performance and after that came the normal constraints: great looks, ease of use, flexibility, price.
The Design
Early in the discussions about the first model, the team agreed to go with a suspended sub chassis, to design a new tonearm and to continue with belt drive.
The choice of motor type was left open until a series of tests, both measurement and listening based, could be analysed. The decision to use a low-voltage low-noise DC motor was actually an easy decision. The far lower radiated field, the ease of accurate short- and long-term speed control together with the lack of cogging, delivered improved measurements and actually, more importantly, sonically a lack of thickness in the lower registers that became known to the team as woomf (or lack of woomf in the case of the DC motor). The motor mounts in an anti-vibration adjustable moulding.
The belt is traditional Thorens: high-precision rubber 4mm wide 496mm long that is ground to a tolerance of 0.03.
Tri-Balance
Traditionally suspended sub chassis turntables often require skills in setting them up which are often seen as almost black magic to the music lover. It was important that these modern turntables were suited to a modern lifestyle, with all its time pressures, and were easy to optimise.
The system therefore had to have three feet and to be in static balance. Thinking of the future: the design allowed alternative weights to balance alternative tonearms.
The three suspensions are easy to adjust from the top with just a hex driver. The TD 309 benefits from being on a shelf or rack that is not massively heavy, as the suspension is tuned to 4Hz deliberately well below and ideal cartridge/tonearm resonance.
The suspension delivers the maximum vertical freedom with minimal totally controlled lateral wobble, which also reduces footfall related problems especially in rooms without solid floors.
Besides the three feet, giving cause for the name Tri-Balance the whole Turntable, Tonearm and Platter are all precision and static balanced.
DC Motor Control
Initially the TD 309 will be supplied with a Switch Mode Power Supply (SMPS) delivering the necessary 12V DC. This was chosen from many on the basic of sonic performance. Later in 2009 Thorens will launch an optional upgraded linear power supply which will improve performance considerably. The nature of power supplies and their interaction with turntables could be the subject of a white paper in itself. Interestingly, linear does not necessarily beat switched mode certainly with significant price restraints. Speed control is by an electronic Low-Q high-precision feedback control circuit. Speed is constant regardless of weight of record or dynamic drag from the stylus. The belt tension is adjustable to allow for belt stretch. Best performance is with the belt as loose as possible before wow and flutter increases.
Platter
The sub platter is precision-machined Aluminium (ALMG1) with a single ring micro-contact area. The diameter of the contact point (121mm) selected by Finite Element Analysis (FEA) to be at the lowest resonant point. Massive oversize fused-silica platter chosen for consistency and sound quality.
Chassis
The base is precision machined from MDF by Computer Numerically Controlled machines to achieve consistently tight engineering tolerances. Very stiff rubber feet on suspension system to stop slipping on shiny surfaces but not to act as a secondary suspension.
TP 92 Tone Arm
The armtube is manufactured from an Aluminium extrusion that is cold worked and rolled for strength. The armtube is surface damped with a random contact material designed to damp resonances without adding emphasis on any one frequency. Reduced modal resonance. Arm resonances and bearing rattle were found to be the most obvious but not only key design parameters. The bearings are sourced in Japan from the leading supplier of high quality, high-precision bearings.
The innovative but simple magnetic anti-skate system features zero stiction and zero friction.
Brass dual-decoupled counterweight.
The headshell is mounted to the cartridge and arm tube separately to allow 5mm of overhang adjustment. Azimuth setting and an extra 6mm overhang adjustment is available at the bearing end of the tonearm.
The Centre of Gravity (CoG) of the cartridge, horizontal bearing and counterweight are on a line with the tonearm giving good dynamic and static balance.
The arm wiring is known as 5.1 as there is an extra ground to allow grounding of lower arm section to avoid current flowing over the bearings. Arm wires are terminated at two high-quality RCA sockets on the rear of the TD309.
Arm is medium mass designed for cartridges of between10 – 20 l0-6 cm.dyne
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