12-09-13: Richardkrebs
Depending upon the counterweights used and the weight of the cartridge, this total can approach 100 grams. The same ball park as my arm.
You have stated in earlier posts that you added 30g of lead to your ET2 plus lead to the headshell and replaced the original plastic counterweight beam with an M10 threaded rod. You have strongly advocated adding more mass to the ET2.
It is simply not possible to add 30 plus grams of lead and arrive at the same net weight to an unmolested ET2.
With my low compliance Denon 103 weighing 9 gms I could balance the ET2 with 35g at the counterweight giving a total mass of around 79 grams. ( That would be about 43 gms using your maths ).
Re your comments on transmissibility -
03-14-13: Richardkrebs
Shown here is a link to the Math on driven harmonic oscillators, a mathematical representation of an arm/ cartridge assembly. It shows in both formula and graphical terms what I have been trying to say. The Math is a bit of a struggle but fortunately the graphs show the results.
en.wikipedia#Driven_harmonic_oscillators
I have pointed out before, the model you refer to applies to a harmonic oscillator like a pendulum. You are incorrect if you think that this represents a cartridge.
The arm/cartridge/record interface has 2 fulcrum points -
The stylus point around which the cantilever pivots, constrained by the groove.
The cantilever suspension point, about which the cantilever also pivots, but which is partially constrained by the rubber suspension damping.
The forces involved are double ended - you have the groove applying a force to one end of the cantilever via the stylus. The other end of the cantilever has forces being applied from the arm motion.
The 2 forces are not in sync because there is a suspension joint between the cantilever and the arm.
In order to conceptualise this, think of 2 people holding a pipe and each one trying to move it sideways out of sync with the other. That is what the cantilever experiences. It is not a pendulum and it is not a harmonic oscillator.
The Wikipaedia example you have chosen does not apply.
Rather than get lost in fanciful mathematics the bottom line is that the cantilever flexes when faced with an eccentric record, even more so with added lead mass.
I quote Bruce Thigpen directly
the cartridge will "see" .55Hz mounted in any tonearm, more so in one with higher horizontal inertia
I don't think Kuzma means the stylus does not deflect at all at .55Hz, that would defy physics
Postulating that the cantilever does not flex with an eccentric record and that adding mass has no impact defies physics.