Tonearm Design & Build Quality
The Priority of Low Level Signal Purity
It is difficult to appreciate why the mechanical integrity of a tonearm should have such an enormous influence on the performance of your system. The first step is to realize that the mechanical movements and electrical signals generated by your cartridge are extremely small – beyond imagination. The electrical signals generated by mechanical movement are amplified thousands of times to produce sound through your loudspeaker.
It follows that the slightest source of unwanted vibration and resonance is magnified to exactly the same extent as movements intended to create the correct signal. Not only can unwanted vibration introduce coloration, but this vibration also affects the cantilever movement to cause distortion. It’s the elimination of this spurious vibration that results in the large differences that exist between mediocre and high end arms.
The Cause of Unwanted Vibration
As the cartridge stylus negotiates its tortuous way through your record grooves it undergoes forces measured in tons per sq. inch. This sends shock waves down the arm tube. What happens to these shock-waves normally? Some of the energy is transmitted down into the deck, but much of it meets the counterweight structure and is reflected back down the arm tube to the cartridge. This is highly detrimental for good sound quality due to the aforementioned facts. There is a secondary reason why the rear end of the arm is an extremely critical area. The counterweight represents by far the highest moving mass in the arm and affects an arm’s performance in ways that are hard to imagine. The counterweight is excited into resonance by the motion of the arm. This means that it should be decoupled and yet also remain rigid to the arm (to avoid introducing other problems). The beauty of the Origin Live designs is that the rear end of the arm acts as a shock absorber. For mechanical waves traveling down the arm from the cartridge and the rear end acts to de-couple the counterweight, whilst maintaining rigidity.
Proven design principles
Origin Live’s first work on tonearms involved removing the rear-end stub of Rega tonearms and upgrading them with a replacement design. Rega rear end stubs are screwed into the end of the arm – this leaves much room for improvement! Origin Live replace the old stub with a new stub. The new stub is torqued onto the arm by a thin high tensile bolt. The new stub is also designed for optimum decoupling whilst maintaining more rigidity in micro flexure than the original. This change also allows the counterweight to be rigidly clamped onto the stub using an Allen bolt. An unmodified arm should not have the counterweight rigidly coupled in this way, due to the old vibration characteristics of the standard arm / rear stub joint. This ingenious modification elevates a good arm into the same league as the super arms and at an insignificant outlay.
De-coupling the armtube
To give an example of the way that Origin Live “break the mould” with design, you only have to observe the “floated bearing” philosophy that is employed in the tonearms. Origin Live bearings are highly specified to suit tonearms – however the bearing houses are deliberately not machined to a tight tolerance as this degrades up the sound to an intolerable degree. We have found that tightly held bearings are not beneficial but this is easily confused with “bearing play”. There are very strong technical arguments to suggest that tightly coupling the arm to the deck via tight bearings is detrimental in the light of listening tests. These confirm that once you house the bearings outside the arm tube, it is best to “float” them rather than “grip” them in a tight fitting housing. People hypothesise about bearing chatter, etc. – maybe this is the case with high resonance arm-tubes and lower quality bearings. However listening soon shows up that there is absolutely no bearing chatter in any of our arms – in fact resonance in our arms is so minimal that it’s extremely difficult to measure in terms of amplitude or deflection.
Minimising ripple effects
Another factor which indicates “floating” the arm tube to be a good idea is that uni-pivots and knife-edge bearings work on this principle. Vibration transmits through the surface which supports the tonearm in various ways. Most significant is “rippling” – not just a simple 1 or 2 dimensional movement as some imagine. Ripple exerts twist or angular force into the structure.
The mechanism of ripple is seen dramatically with very fast frame photography taken inside ships undergoing underwater explosive shock. When a mine explodes under a ship, the inside becomes a death-trap of flying fittings that have become detached due to the underwater shock wave. Anything attached to a side wall or part of the ship structure detaches at speeds of up to 600Km/hour. The reason this happens is due to the shock waves setting up ripple in the ship structure and side walls.
In the micro-vibration that occurs in analogue replay, ripple effects are very important. Uni-pivots are rigidly grounded in one sense but decoupled completely from ripple effects. However (and it is a big “however”) they cannot hold the cartridge well against torsion exerted by bass notes. Widely spaced conventional bearings reduce ripple effects as do floated bearings. However they have the added benefit of holding the cartridge rigidly, resulting in a more dynamic bass performance.
Low friction bearings
The Silver tonearm and upwards use special low friction bearings that improve in specification right up to the ceramic bearings used in the Conqueror. Long and intensive research has been invested in bearing design as it plays a very significant role in sound quality. The influence of bearing friction is surprising and can only be put down to the fact that it not only allows improved tonearm tracking but more importantly minimises environmental vibration from affecting the arm. This effect can be likened to putting the tonearm on ice. The ice can ripple but due to low friction and inertia the tonearm is affected much less in terms of vibration and motion.
The quality of cable required to transmit the extremely low level of signals generated by cartridges needs to be of the highest calibre. Origin Live has invested exhaustive research into this critical area over many years and have developed the best sounding cables possible.
Dual Pivot design on higher arms in the range
Dual pivot combines the virtues of ultra low friction uni-pivots with the stability of conventional gimbal bearings without any of the drawbacks. The pivot points are made from a special grade of Tungsten which sit in hardened steel cups. Jewelled bearings were rejected as they are prone to shatter and proved too fragile with no real sonic advantages. The bearings controlling horizontal movement are a low friction design specified by Origin Live.
Carbon Hybrid tube (higher range arms only)
The armtube uses a special carbon fibre construction combined with Ebony and expensive metal alloys. Carbon fibre is both strong and inert. However, even the most inert materials still have “tone”, and the only way to further reduce resonance is to combine other materials into the mix.
This principle is best illustrated by the legendary “Stradivarius” violin. Stradivarius found that particular types of wood in special combinations, made all the difference in the world to the sound produced. The same principles of endless testing with pitch-perfect hearing has been conducted over many years to refine Origin Live arm designs – the only difference being that resonance is being eliminated rather than created.
All arms include built in VTA adjustment – arms from Encounter and upwards have the advantage that this adjustment can be carried out from on top of the armboard. Lower arms in the range require accessing the underside of the armboard to tighten the clamping nut
Correct azimuth is set at factory using highly accurate jigs. However, cartridges are not always manufactured to super fine tolerances and therefore some people like the ability to adjust azimuth themselves. We provide this facility on all our upper arms from Encounter and above.
Tonearm Effective Mass and Cartridge Matching
To minimise vibration it is often recommended to match the tonearm effective mass to the stylus compliance. However in practice, matching the arm effective mass is nowhere near as important as very low resonance and structural integrity within the arm itself. Yes, compliance matching can help in badly behaved arms but with a well designed arm it’s of such low significance that it can be ignored.