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In Reply to: Re: excuse me posted by OMalley on September 11, 2006 at 13:19:20:
Symmetry is important to vinyl replay I think, especially stereo.If the bearings supporting the 'beam assembly' (cart., tube, counterweight) are spaced (equally) well away from it's centre of mass, they 'take the weight' equally and will behave in a more ... linear (?) way when they inter-react with the yoke, the arm-pillar, the arm-baord or plinth, the equipment stand .......................
Follow Ups:
Tires wider apart make for more stable secure traction. The outrigged weights may compensate somewhat in this regard, sort of like the bar a tightrope walker uses.
The outrigger weights act in two ways. My guess is that they absorb the vibrations and resonances of the vertical bearings. Second they add unsprung mass to the arm itself so it increases mass without increasing effective mass of the tonearm.
They are not attached to the arm, just the bearing/yoke assembly, so they add zero mass to the arm.i can't speak to them absorbing resonance from the bearings but their purpose, mass qua mass, is to add that mass outward on a horizontal plane to create, litteraly mass/inertia to slow down the arms movement along that plane, or to stablilize the arms back and forth movement.
Why? When the cartridge is 'excited' by the groove it will over-react [think Grado here in the extreme] and cause the arm to react as well. Some think this is good in that the arm is nible and allowing the cart to 'do it's thing.' But, stopping that arm from reacting is the point. Keeping that arm stable but fluid keeps that cartridge/stylus riding smoother/deeper into the groove. The cartrdige should move and send that energy up then cantilever into the coils, etc. Hold that cart still and stopping the arms reactive movement stops feedback to the cart. NO WIGGLING. Keep that arms steady to keep the cart steady so that the sylus/cantilever can react to the grooves ONLY means ... a higher level of fidelity[truth in movement], dynamics[deeper in the groove], detail, able to calmly reproduce subtle changes in the groove.
Can you see that picture?
I would describe this modification as akin to the balance beam a tightrope walker uses. Well sort of.But locating the two largest masses, namely the cartridge and the C/W at the very extremes of the "stick" contributes to the same type of stabilization. The idea of the C/W close to the pivot is counterintuitive.
The bearings are in the armtube not the yoke so they can be adjusted more easily for preload.Just because some guy has time on his hands and has created Gandystein's Monster doesn't mean it is all sound engineering. There is alot of NIH going here and there.
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I didn't come here for an argument, Garth, just some considered input.It should be obvious how important 'symmetrical' behaviour is in a tonearm playing a stereo source. Imaging?
I don't know why you're even taking issue with my stating that the cost-compromise design of the Rega included a far-from optimal way of pivoting the arm-tube (for all the arm's many other virtues, which make it such a playground for inventive tweakers).
Was that it offset the angle of the vertical pivot to the angle of the tonearm.Technically this is done to minimize the torsional effect of the counterforce to the stylus.
so symetry is not always the best method. Sometimes offseting angles are better....
And offset counterweights is still up in the air!
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