quiddity
Responses from quiddity
| Why is the price of new tonearms so high Axelwahl Your suppositions are correct and the figures are reasonable. If we model a 100 g counterweight positioned 50mm behind the pivot, its contribution to the effective mass of a 225mm arm is 4.94 g*. If this is the position for VTF of 20mN, i... | |
| Why is the price of new tonearms so high DertonarmThat is completely wrong (again). The moment of inertia of a rigid body does not change with movement.Yes we are talking differnt models. Mine is a model of what is happening, yours is a fiction. | |
| Why is the price of new tonearms so high Kirkus We are indeed "singing from sheet". The point that seems to be lost on the other participants is that this is a dynamic analysis. This follows directly from D'Alemberts principle. Mark Kelly | |
| Why is the price of new tonearms so high DIVIDED BY Rotational compliance is linear compliance DIVIDED BY the square of the effective length. Sorry I wrote it the wrong way around. | |
| Why is the price of new tonearms so high Kirkus I composed the above offline before you posted again, it is in response to your post from last night (my time). Since the issue of efective mass is causing confusion, I can take it out of the argument by reverting to rotational units. If we... | |
| Why is the price of new tonearms so high Kirkus You make a good point so I'll answer that first. The answer should make it plain that everything Dertonarm has said in response is wrong. I chose the example I used because the frequency was far enough away from practical cart/arm resonanc... | |
| Why is the price of new tonearms so high T-Bone Yes, that is what I am saying. It follows from a simple torque balance on the arm according to D'Alembert's principle. Rather than boring everyone by converting forces to torques and computing moments of inertia, I used the concept of equiv... | |
| Why is the price of new tonearms so high Completely wrong.Your first paragraph makes no sense: the effective mass of an arm is simply the moment of inertia divided by the square of the effective length.In the second para you present a supposition which I have already shown to be wrong bu... | |
| Why is the price of new tonearms so high Next a look at the effect of "warp riding". Assume a standard "taco warp" so the warp frequency is 7 rad.s^-1. This gives a maximal velocity of .007 m.s^-1 in the vertical plane for each mm of vertical warp and a maximal acceleration of .049 m.s^-... | |
| Why is the price of new tonearms so high I've kept out of this thread but now that we are getting contributions from people who actually understand tonearm design I thought I might contribute a little.Frank it is true that VTF will increase with record thickness but by my calculations t... | |
| Dedicated phono-pre for MM only? Kirkus Thanks for that, I will have a more careful look at the design calculations for my MM only phono amp. The input stage is currently using 2SK389BL as diff amps with simple resistive loads (balanced inputs, there's no need for a feedback conn... | |
| Dedicated phono-pre for MM only? Kirkus I'm not sure I understand your point about dynamic capacitance of JFET vs V/T inputs, and if I do I'm not sure I agree with it. Assuming that you are talking about junction thickness dependent capacitance varying with drain - source voltag... | |
| Micro SX-8000 II or SZ-1 ThuchanAssuming that question was directed at me;I think it's an interesting contrast with the Micro Seiki approach. The MS product shows a level of design sophistication and engineering input which is well beyond that achieved by VPI.This is refl... | |
| Micro SX-8000 II or SZ-1 I'd like to confirm T-Bone's opinion. Two sx8000s chained together would be about 1/10th as effective as the high inertia motor assembly of the SZ-1, from the point of view of inertia alone. The two platter solution would however result in far les... | |
| Micro SX-8000 II or SZ-1 Let's not turn this into a discussion of Saskia, it's meant to be about the Micro Seikis. I used it as an example only. |