Problem with magnetic: the magnitude of the force changes linearly with distance between the magnet and its ferrous target, as the tonearm rotates in the horizontal plane. But The skating force is not linear in the way its magnitude varies. In that respect Magnetic AS might be inferior to a weight on a string, at least the latter is more or less constant with respect to the magnitude of the AS force. Just a thought.
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For me I prefer weight on a string for 2 reasons - You can measure the anti-skate accurately I tend to use very little anti-skate - somewhere between 25 & 30% of the tracking force as recommended by Shure, Grade & van den hul. Many sprung or magnetic antiskate mechanisms cannot get that low with any precision. |
Can you explain how you determine the 25 - 30% via this method? |
Whilst I agree with high horizontal mass being not ideal, in reality the lateral forces on the cantilever are still lower than a pivoted arm - this is documented on the Eminent Technology website. In fact here is an explanation from Bruce Thigpen himself The untold parameter of a pivoted tonearm: To minimize tracking With the ET-2 the side loads to accelerate the tonearm at .55hz So as you add mass, this side load value of the ET-2 goes up As an example I ran a high compliance Shure V15vmr ( with stabiliser removed ) in the ET2 for 10 years without changing the stylus. The cantilever was still dead straight after 10 years. The only significant mod I did to the ET2 was to run magnetic damping for the horizontal movement using eddy currents. |
Re parallel trackers, look at the Simon Yorke Aeroarm (no longer available). Effective mass of the arm is around 25% of a typical 9 inch pivoted arm because it is only 2.5 inches long. Why do most other designers of parallel trackers keep the length near 9 inches just because most pivoted arms are 9 inches? I have closely observed the cantilever of 6 high-end cartridges mounted on my Aeroarm and there is no sideways torsion whatsoever. Tracking is totally secure at the low end of most manufacturers' recommendations. van den Huls track securely at 1.6g. Lightweight Ortofons like A90 and A95 are a match made in heaven with Aeroarm. I will never go back to pivoted arms.
@dover Please explain why you think the skating force does not change linearly as the record is played. Surely it is just a question of geometry? |
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