The A.C.T. 2

In the award winning ACT Two, Advanced Composite Technology is used to create the lightest, stiffest, most highly damped tube on the market which is almost 15% lower in mass than the ACT 0.5. The ACT Two provides all the technically proven virtues of the ACT 0.5 but in a more refined package.

The ACT Two is further testimony to our single minded commitment to the analogue medium and is a worthy addition to the Wilson Benesch product range.


Arm Tube

Wilson Benesch Ltd was the first company in the world to produce a fully moulded, single component arm tube. Torsionally it is typically ten times stiffer than conventional arm tubes. It is three times stiffer in bending and an order of magnitude better at damping audio frequencies. Carbon fibre is unquestionably ideal for this function. The structure is formed from two contra rotating helixes of pure carbon fibre, much the same as some of the most effective natural structures which have benefited from millions of years of design refinements.

The shape of the beam is also quite natural as it has been determined precisely by its function and physical limits, rather than by the crudities of a manufacturing process as in the case of metals or ceramics. As a result, material use is exact and exists only where it is required. It should be noted that this is quite different from the mass produced straight carbon fibre tubes being used in other designs.

The performance of the carbon beam is matched by the equally effective and equally unique Kinematic bearing. The combined function of the bearing and counterbalance provides the ideal mechanism for a tonearm movement. The benefits of this technology for the end user are significant. All aspects of reproduction are improved as the cartridge is provided with the opportunity for the first time to do its job without being heavily influenced by the function of the system designed to support it.


Kinematic bearing

The bearing system of the ACT 0.5 and ACT Two tonearms is unique, although its operation is derived from a long established engineering principle, namely Kinematic location. Basically, the theory of Kinematics states that there are just six types of motion that a body can experience. Movement in the three axes of our three dimensional world and rotation in each of these axes. These motions are known as the six degrees of freedom. To fix a body in space one must prevent movement in each of these.

The kinematic bearing system allows just two degrees of freedom. Rotation about one axis to track the record and rotation about a second axis to allow for any vertical movement of the cartridge. All linear motions are completely eliminated, thus giving the cartridge a super stable reference from which to carry out its task as a measuring instrument. Indeed the classic application of Kinematics is in the design of high precision laboratory measuring equipment.

The bearing is stabilised by the low slung counterbalance beams which eliminate radial movements of the tube. The simple design also permits fine adjustments of azimuth. Single point contact between the counterbalance and beam is provided by four carbon chrome balls thereby avoiding troublesome resonance from a compliant type of mounting. The whole system is simple and reliable; there is no need for adjustment; it is unaffected by temperature change; pre-loading is no longer a concern; damping is catered for; the whole component functions without any noise. It will perform as well in thirty years time as it does today! It is important to note that neither a ballrace nor a uni-pivot can claim to satisfy the requirements of Kinematic location or indeed the other advantages incorporated into this deceptively simple solution.