The OA2 Tonearm
The Engineers at U-turn Audio have release a greatly improved tonearm for the Orbit Turntables – The OA2 Tonearm.
The OA2 tonearm has the same low center of mass and relatively low effective mass as the original. The OA2 uses high-quality materials: glass-filled nylon, aluminum, brass, and stainless steel. The OA2 tonearm is completely designed and assembled at U-turn Audio in the USA. But there are four things that are very much new about it:
1. New gimbal bearing design
The OA2 has been upgrade from a Uni-pivot design to a gimbal bearing design, consisting of two pivot axes connected perpendicularly. The vertical axis of the new bearing consists of two stainless steel cone-shaped pivots that rotate on hardened steel ball bearings. High-quality radial ball bearings are mounted to a machined aluminum shaft for the horizontal axis. The new gimbal design has less bearing friction, which allows the stylus to move more freely as it tracks the grooves of your record. This translates into less distortion and better imaging.
2. Heavier counterweight
The OA2 features a redesigned, higher-mass, stainless-steel counterweight. This allows the OA2 to accommodate a wider range of cartridges weighing up to 7.2 grams. Popular upgrades such as the Ortofon 2M Series, Shure M97xE, and Audio-Technica 440MLa can now be installed. The new counterweight has an internal clamping mechanism, which makes it easier to fine-tune VTF when switching cartridges.
3. Internal anti-skate
When you play a record, friction between the stylus and record surface produces a skating force that pushes the tonearm to the center of the record.
The OA2 tonearm is designed with an anti-skate mechanism consisting of a small spring that is pre-set at the factory. This mechanism provides a small amount of outward force to counteract inward skating force.
The new anti-skate mechanism allows the stylus to sit more precisely in the center of the groove, which improves trackability and further reduces distortion. The difference is most noticeable on difficult-to-track passages that contain large amplitudes or complex waveforms (e.g. trumpets, percussion).
TEST NOTE: Geardrum Audio put the new OA2 through the Shure trackability test. It scored an impressive 6 out of 6 with no inner or outer groove distortion.
4. Improved tonearm geometry
The effective length of the tonearm was increased to allow for the use of Stevenson, Lofgren A (Baerwald) or Lofgren B geometries. Each type of geometry has its benefits. For example, Lofgren B has the lowest average distortion across the entirety of the record, while Stevenson is best for reducing distortion on the inside of the record. With the new tonearm, we are now using Lofgren A as the default alignment for all Orbits (this is something that you can easily adjust if you prefer an alternative geometry).
Source: vinylengine.com
The OA2 tonearm finish has been upgraded. Glass-filled nylon parts are now textured for a more uniform finish, and aluminum parts are tumbled in walnut shells for a more polished look and feel.
U-Turn Audio has the best customer service available – contact them directly if you have more questions.