Hi Chris, BTW the pressurized air bottle is true. :-)
I forgot to answer an earlier question of yours: I prefer to use less counterweights farther out on the I-beam. I prefer it because this way the center of gravity of the arm is more centered along the bearing, and because I have less lever forces on my semi-springed subchassis. It helps to float the arm better across it's way.
It also reduces the maximum lateral mass, effective at "DC", below the resonance frequencies of arm/bearing and I-beam/counterweight.
Less counterweights farther out in effect tunes the I-beam / leaf spring resonance lower down. In the end, this is a more important aspect than the leaf or counterweight looked at separately I think.
I went through many such tests during the 80's and beginning of nineties, taking some of them up in the last years.
I didn't like the single leaf springs with my medium to low compliance cartridges, I preferred the double spring ones - I don't think I have a triple leaf I-beam.
There is another aspect of the I-beam, which is critical / sub-optimal: The weights are not centered around the I-beam, ie. it exerts an offset torsional force on the leaf. This means that any vertical movement of the arm activates a hidden torsional resonance, which slightly modulates tracking force. The vertical axis is the one axis, where you want *absolute* "true inertia", and as few resonant modes as possible, including arm resonances, as it affects the critical downforce.
My feeling is that the stiffer beams control this aspect better than the single leaf beam.
I always preferred the I-beam leaf with a bit more damping than originally provided, using BluTak.
For balancing I move two Blue-Tak "saddles" along the I-beam, and the arm lever extension, to keep lateral forces equilibrated.
My ET2, now with ET 2.5 bearing is an early one. I ordered the bearing for around 0.8 bar (ca. 11 psi) and it still runs OK with ca. 3 psi. Though below ca. 6 psi things go audibly downward, the magic disappearing somehow. In fact the ET 2.5 has "simply" more surface and is therefore already stiffer, but the price is a higher lateral mass, probably 10g more.
Sending the arm from Switzerland to the US - and parting from it - would probably affect my sleep... not in the best way. :-) It works good enough... I'm Just checking lateral balance after adjusting the VTA.
I forgot to answer an earlier question of yours: I prefer to use less counterweights farther out on the I-beam. I prefer it because this way the center of gravity of the arm is more centered along the bearing, and because I have less lever forces on my semi-springed subchassis. It helps to float the arm better across it's way.
It also reduces the maximum lateral mass, effective at "DC", below the resonance frequencies of arm/bearing and I-beam/counterweight.
Less counterweights farther out in effect tunes the I-beam / leaf spring resonance lower down. In the end, this is a more important aspect than the leaf or counterweight looked at separately I think.
I went through many such tests during the 80's and beginning of nineties, taking some of them up in the last years.
I didn't like the single leaf springs with my medium to low compliance cartridges, I preferred the double spring ones - I don't think I have a triple leaf I-beam.
There is another aspect of the I-beam, which is critical / sub-optimal: The weights are not centered around the I-beam, ie. it exerts an offset torsional force on the leaf. This means that any vertical movement of the arm activates a hidden torsional resonance, which slightly modulates tracking force. The vertical axis is the one axis, where you want *absolute* "true inertia", and as few resonant modes as possible, including arm resonances, as it affects the critical downforce.
My feeling is that the stiffer beams control this aspect better than the single leaf beam.
I always preferred the I-beam leaf with a bit more damping than originally provided, using BluTak.
For balancing I move two Blue-Tak "saddles" along the I-beam, and the arm lever extension, to keep lateral forces equilibrated.
My ET2, now with ET 2.5 bearing is an early one. I ordered the bearing for around 0.8 bar (ca. 11 psi) and it still runs OK with ca. 3 psi. Though below ca. 6 psi things go audibly downward, the magic disappearing somehow. In fact the ET 2.5 has "simply" more surface and is therefore already stiffer, but the price is a higher lateral mass, probably 10g more.
Sending the arm from Switzerland to the US - and parting from it - would probably affect my sleep... not in the best way. :-) It works good enough... I'm Just checking lateral balance after adjusting the VTA.