A couple of thoughts, first I could see it being a deal more difficult to put a 1200 arm and adjustment mechanism into a Rega plinth than to put a Rega arm into a Technics.

The former will require some drastic surgery on the plinth I would expect.

Secondly, and perhaps more apropos, similar appearing arms can have widely varying effective mass by utilising varying armtube materials or thicknesses, consider the SME 3009 of the period where effective mass varied from around 7 gm to around 13 gm.  Since the effective mass provides the inertia against which the stylus/cantilever must push whilst attempting to move generating elements relative to each other to generate a signal, it is arguably of more importance than VTF in optimising tracking.

Certainly the practise of "mass loading" medium mass arms, such as the RB250/300 to optimise the performance of low compliance cartridges such as the DL-103 is an example of this.  I rather feel that varying the impedance loading of MC cartridges has a similar effect, although not to the same degree.

It may well be that the present medium mass 1200 arm is of higher effective mass than the similar arm fitted to the Planar 3 at a time when higher compliance cartridges were more common.  The very light SME 3009 SIII was developed to meet the requirements of the Shure V15 as were many other arms of that period.

Conjecture to be sure, but is that not the scientific method ? - formulate a theory that fits the observed facts and then test it ?

Over to you tester 1. 

Erm, thanks, I think  

I'm no "born again" policeman so I hope the duties are largely ceremonial. 

I read through posts after this one and got a bit lost, so I've gone back to the beginning. My first reaction is that this sounds mostly like a simple case of mistracking. Do you use a guage, like the Shure, to measure tracking force? I've often found that the settings achieved by trusting the counterweight dials built into arms like the Technics to be less than accurate.

On the Rega theme, I did an internal rewire to Litz wire using an old B string to draw the wires through. It makes a difference on an P3-24 so I imagine a greater benefit on Planar 1-3. If you have the tools and electronics experience, it is a lot easier than you would expect! Well worth £10 and an hour or two's work. There are some excellent DI4Y services out there.

Thought I might resurrect this old thread rather than clutter the Genera thread.

Graham, which motor did you order for the P3 ? - the new 24v one or the older one ?

Point being, if they have not/cannot supply, I have a spare of the older type here that I am unlikely to use having replaced it with the 24v version and speed switch PS.

It is still the newer design with the adhesive pad mounts rather than the old style rubber "O" rings.

Also have the PCB and IIRC some adhesive mounts that I did not use for the new 24v motor.

Motor has been fitted with an adjustable thrust bearing too that did not go on the 24v one.