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While reading a paper in a recent AES Journal issue, I ran across this interesting statement:

it might be interesting to know that
the stylus in the groove can experience accelerations of up
to 1,000g [12] (g being the acceleration of gravity of 9.81
m/s2). This is about 100 times larger than the maximum
value experienced in military fighter jets [13].
3

That is quite an extreme load for a mechanical component.

Tom,

1000g's for something that is so low mass as a phono stylus isn't really something to worry about. For instance, if a stylus has a tip mass of 0.5 mg, then the transient load is only 0.5 gram. The VTF (assume 1.5-2.0 grams) and proper alignment and antiskate setting would hopefully counteract this and keep the stylus in the groove. The Shure V15V supposed to have had a tip mass of 0.1 mg, which means the transient load would be 0.1 gram, which would be well within the tracking force spec.

I assume the direction of the accelleration force is primarily vertical (common high amplitude low frequency, i.e., 1812 Overture cannon blasts on the infamous Telarc recording), though I recall that recording had a notorious sideways jog that sent many a stylus out of the groove.

David

The cartridges may have a low tip mass, but they also have very small contact area. Therefore even if the force is low, the pressure is high. BTW, I still have my Shure Ultra 500 and a spare stylus.

Tom,
I use a Shure Ultra 500 with an original Micro Ridge stylus as well in my SME 3009 Series III low mass arm.

I have the Telarc 1812 original pressing and it use to launch low compliance cartridges across the record. The Shure just kept tracking without problems at 1 gram tracking force.

That was all horizontal displacement where you can see the almost step function in the groove.

The stylus groove pressure is high enough that the vinyl flows around the stylus in a fluid state.

_________________
Walt

Yes, even the later pressings of the Telarc were reduced in level due to the tracking problem.

The National Symphony performed the 1812 with the Army Howitzers years back. Dynamic range galore!

I have had reissue of LPs on CD that were good and some that were terrible. Same story of decisions made in remastering.

I found Mr. Jovanovic's other paper also interesting -- entitled "New Analytical Results for Löfgren C Tonearm Alignment" with the following statement catching my eye:



There is a follow-on article from Peet Hickman "Analysis of Löfgren`s Tonearm Optimization" that discusses the math --



All very interesting --

_________________
"We are all inventors, each sailing out on a voyage of discovery, guided each by a private chart, of which there is no duplicate. The world is all gates, all opportunities."
Ralph Waldo Emerson