Linear tracking vs. Pivoted tracking tone arms.

RJM, There are adapters to convert a P-mount tonearm to use non-Pmount cartridges.  Usually, they are inexpensive.  Check with Sound Smith for a good one.  eBay for a cheap one.

Atma-sphere et al, There is one type of pivoted tonearm that exhibits the property of a low vertical inertial mass with a high horizontal inertial mass, a la most SL tonearms. That is the Dynavector DV series. Rather than try to translate what Dynavector says about this feature of their tonearm, I am quoting here the DV505 owners manual:
www.dynavector.com/etechnical/505manual.html
The verbiage hints at why a high horizontal mass has some advantages as regards low frequency resonance control. As I think I mentioned once before, there are also a few vintage conventional pivoted arms that have obvious added mass on their lateral aspects, added usually at the pivot, e.g., the SAEC, to name only one brand. My point is that there are possibly some theoretical advantages to having a low vertical and high horizontal inertial mass, combined in one tonearm. Ralph, I would be interested to know what you think about this.

I just found this quote in the DV507 MkII brochure:
"The DV507 bi-axis tone arm has a large inertia for horizontal movement and a very small inertia for vertical movement. We shall now explain the reasons why this is advantageous.

It is well known that a cartridge generates an audio signal by the differential motion between the cantilever and the cartridge body. Consequently, if the supporting point of the cartridge (the tonearm) vibrates, the tonearm motion affects the audio signal.

In these conditions, the signal, which causes the tonearm to vibrate is of low frequency and large amplitude.

In the currently used 45-45 stereo record cutting procedure, low frequency signals are almost entirely recorded in a horizontal direction. This means that the low frequency signal, which can cause vibration in the tone arm, exists only as a horizontal force.

The tonearm therefore must have sufficient effective mass and rigidity in the horizontal plane in order to provide a stable platform for the cartridge.

On the other hand, for the mid to high frequencies, the effective mass of the tonearm should not be too large since the combined mass of the cartridge and the head shell need to be taken into account as well. In particular, where records have a warped surface, the vertical effective mass needs to be small enough to ensure a good tracking ability on such surfaces.

To summarise, the tone arm should have a large effective mass and enough damping in the horizontal plane and at the same time a small effective mass in the vertical plane."

I'm just sayin'...

Kinda have to agree with Ketchup. Was going to say the same thing. Check your friend's set-up accuracy and his cartridge, if indeed there is any basis at all for your hypothesis that his playing your LPs on his rig damaged them.

Dover, I do think Tony has a point about mating an air-bearing tonearm with a spring-suspended turntable. I think I have read elsewhere that such a pairing can cause problems. Especially I was dubious how a Linn LP12 would mate up with the ET2. (Someone else on this thread has that combo.) However, your success with the Sota/ET2 would go to show that what is problematic in theory is often OK in practice.

Dave, I had not seen those data from John Ellison. Thanks for the URL. Actually, given the premise that one cannot "hear" tracking angle error; one can only hear tracking distortion, I find it surprising in fact that there is so little difference between the pivoted example and the SL example with 0.5mm overhang error, comparing only the red curves for distortion. At worst, when the stylus is between 80 and 90mm from the center of the LP, the pivoted arm gives about 0.7% tracking distortion vs ~0.2% for the very slightly misaligned linear tracker. At other distances from the center of the LP, the difference in distortion is much less and sometimes in favor of the pivoted arm. I wonder at the audibility of this difference (but I know you say you can hear it). I also wonder how many SL tonearms are running with this much set-up error and worse. I would guess it is not uncommon for there to be an +/-0.5mm error in set-up.

Oh, I'm not arguing against SL tonearms as regards geometry. That would be illogical. I admit I am just too lazy to mess with one. So much else in my audio system requires regular care, and then there is my penchant for tweaking. Sometimes I just want music.