Eminent Technology ET-2 Tonearm Owners

Dover
Again you enter into needless personal attacks

Does the cantilever deflect due to the higher lateral forces imposed upon it?
I see no movement with my cart tracking eccentric records and the math predicts none. However in absolute terms no one could say that there is zero deflection. A more appropriate question would be. Is the additional horizontal mass dangerous to the health of the cartridge, which has been your accretion all along. It would seem that this is not so. There appears to be no issue. If there was it would be all over the web that arm XYZ is a mass murderer.

The second important question should be. Does increasing the effective mass of the ET2 make its performance better or worse. For those of us with untrained ears the answer is yes.
We would need to include BT in at least a semi trained ear camp, as he advocates stiffening the counterweight beam on the arm he designed when using low compliance carts. This is counter to what you advocate when you loosen further the leaf spring.

I like your analogy of a pipe being moved independently at each end.
This of course presupposes that the cartridge body is moving relative to the groove. If it is not, which is what we want, the cantilever has one fixed pivot point at the suspension. The stylus end describes an arc as it traces the groove.

Richardkrebs,

There was no personal attack. I simply addressed the anomalies and reasons for the errors in your post dated 03-14-13.

I will review your latest post tomorrow.

Richardkrebs

With regard to cantilever deflection on eccentric records, it is clear you are confused. Let me explain:

Your original statements on this matter were and I quote
03-12-13: Richardkrebs
Below this resonant frequency the cartridge is able to move the arms weight, start it and stop it, without cantilever deflection. I do not need to talk to cartridge manufacturers to confirm this. Do the math.

03-13-13: Richardkrebs
What I have constantly said is that this force will not be enough to deflect the cantilever while tracing an eccentric record, provided the resonant frequency of the arm / cartridge system is above 0.55 hz for a 33 rpm and 0.75 hz for a 45 rpm record.[/quote]

Now however your position is, and I quote from your post of 03-16-13:

I see no movement with my cart tracking eccentric records and the math predicts none. However in absolute terms no one could say that there is zero deflection.

Richard, you have made two conflicting statements in two consecutive sentences in your latest post of 03-16-13.

Your first sentence states the maths predicts no cantilever deflection.
Your next sentence contradicts that sentence and all your previous assertions for the past week or two and states that no one could say there is no deflection.

Should readers of this thread take it that you now agree that Bruce Thigpen and I are correct and there is cantilever deflection below the resonant frequency. You were incorrect when you stated "Below this resonant frequency the cartridge is able to move the arms weight, start it and stop it, without cantilever deflection".

Dover.
No confusion at all. In Engineering, the term absolute is.....absolute.
By way of example, over on the TT drive thread, a fellow poster said that " there is no stretch in the silk thread I use to drive my platter." or words to that effect. Within the loading the thread sees, this statement is almost certainly true. However if he had said that "there is absolutely no stretch..." he would be making an indefensible statement.
One would also be very unwise to say that "tracing an eccentric record with a standard ET2 causes absolutely no cantilever deflection"

Hasn't this discussion run its course.
Like the light weight ET2, there are many heavy weight linear arms in use, performing well, producing beautiful music.

Richardkrebs -

You have now conceded after 4-5 weeks of obfuscation that there is cantilever deflection on eccentric records below the resonant frequency.

It follows that adding mass increases deflection as I asserted back in February. On 02-16-13:

By increasing the horizontal mass of the arm significantly, when you play an eccentric record the increased resistance to motion from the additional mass will result in increased cantilever flex.

Your latest comparison of the deflection of a sprung cantilever with the elasticity of a silk thread is at odds with the application of scientific principles.

Do we need to spend another 5 weeks going through the difference between the modulus of elasticity of a woven silk thread and the bending motion of a cantilevered suspension.

Hasn't this discussion run its course.

This is the third time that I'm aware of over the past weeks that you have requested a discussion be terminated. It is not obligatory for anyone to participate. Whilst you are keen to champion your Technics modifications and your own homebrew tonearm, this is not your personal thread.

No confusion at all. In Engineering, the term absolute is.....absolute.

This not correct. The discussion we are having is on the cantilever flex generated by an eccentric record. This is not absolute as there are variables involved, to wit - the mass and inertia of the arm, the compliance of the cartridge and the level of eccentricity in the record.

The laws of physics are absolute. Correctly applied they enable us to develop mathematical models for scenarios that are not absolute.