What innovative, unconventional cartridge designs can you recommend?

@richardbrand,

The G’s is totally a function of the frequency being produced and the modulation and there is a calculation for it - read this article - Dr. A. M. Max, Disc Phonograph Records, Max, RCA Engineer Magazine 1966-08-09 1966-08-09.pdf which also calculates the force from a spherical stylus of different dimensions and different VTF, and the "calculated" forces at 2.5-gm VTF can range from 65,800-psi to 121,300-psi.  However, the G-forces developed have only a minor impact and it’s because of the very low effective tip mass with modern cartridges being very low Effective Tip Mass | myhi.fi.  

Note that the record does deform under the forces of the stylus, but provided the forces remain in the ’elastic’ region, no permanent deformation occurs.  However, if the stylus mass is too high (generally considered >5-gm), then the forces exceed the elastic region and ’plastic’ deformation can occur.  The Dr. Max article addresses the elasticity of the record with greater detail in this article - Groove Deformation in Gramophone Records.

FWIW, on a different but related to records, this very recent article 2023, is excellent on the subject of tracing distortion Tracing Distortion on Vinyl LPs
 VLADAN JOVANOVIC, 22236.pdf.

Take care,

Neil

@antinn 

calculates the force from a spherical stylus of different dimensions and different VTF, and the "calculated" forces at 2.5-gm VTF can range from 65,800-psi to 121,300-psi

Agree that the highest G-forces are only generated where the acceleration of the stylus is at its maximum.

Since a long ton is 2240-lbs (and is close to a metric tonne but about 10% more than a short ton of 2000-lbs) we can divide 65,800 and 121,300 by 2240 to get about 29 and 54 ton per sq inch.  This is beyond the breaking strength of mild steel and way higher than my calculations for a line contact stylus.  Something has to give, and what gives is the vinyl!  It deforms elastically around a conical stylus, increasing the contact area and reducing the pressure.

I recall advice that the same side should not be played immediately in order to give the vinyl time to recover its original shape.

So, comparisons of cartridges, playing the same track with one cartridge right after the prior cartridge played it, is not good practice?

We could suppose they cannot sound the same.

Charles Kirmuss says wait 24 hours to play an LP again, they have to cool.

@richardbrand ​​@elliottbnewcombjr, 

I recall advice that the same side should not be played immediately in order to give the vinyl time to recover its original shape.

Charles Kirmuss says wait 24 hours to play an LP again, they have to cool.

It's probably best not to play the same track repeatedly, but for the album, there is a 15-20 min delay before the same spot is replayed, and the how much is the record actually heating - very little.   

The thermal conductivity of the diamond is the highest of all materials - ~1000 Watts/(meter-deg-Kelvin) - List of thermal conductivities - Wikipedia. Compare that to PVC or most other plastics - Plastics - Thermal Conductivity Coefficients (engineeringtoolbox.com) at <1-W/m-K).  Additionally, the cantilever even if boron (~27 W/mK) which has the least of the various cantilevers (other than cactus) has a thermal conductivity much higher than the record. The diamond and cantilever are going to transfer the heat much faster and therefore heat much faster than the record.

Additionally, consider the record is moving between 51-cm/sec (510,000-microns/sec)-at the outer cut to 25-cm/sec (250,000-microns/sec) at the inner cut. If the stylus contact width is 2.5-micron, the stylus is in contact with the record at a spot 2.5-microns wide at most (2.5-microns)/(250,000-microns/sec) = 0.00001-sec (10 microseconds).

The amount of energy (watts) to produce heat can be no more than what is being used to spin the record - it's the conservation of energy, and as the record rotates, air is being moved which provides some cooling.

I don't believe the heating effect is significant.  After all vinyl is a plastic which is permanently deformed when heated and pressed as a record.  At room temperatures it deforms elastically, springing back to shape eventually.

Let's estimate the friction watts converted into heat when a 1-gram stylus tracks a record groove at about 50 cm/second (@antinn).  For simplicity let's take a coefficient of friction of 1, so the drag on the platter is also 1-gram.  In reality, friction is a bit less, but there is extra drag with modulated passages.

From Wikipedia

At average gravity on Earth a kilogram mass exerts a force of about 9.81 newtons

Let's round a kilogram to about 10 newtons.  So a 1-gram mass exerts a force of about 0.00001 newtons.

When an object's velocity is held constant at one meter per second against a constant opposing force of one newton, the rate at which work is done is one watt

The record periphery is spinning at 0.5 meters per second, so the work done by a 1 newton stylus would be about 0.5 watts.  Downsizing to one gram, gives 0.5 x 0.00001 = 0.000005 watts, or 0.005 milliwatts or 5 microwatts.