From Linn we have had (over the last 25 years):
* the Cirkus bearing and its fixing arrangement to the top-plate.
* the new top-plate, having a fixing bolt in the motor corner, to help the top-plate mate to the plinth better (so motor vibrations are transferred better to the plinth).
* new power supplies for the original AC motor - and now the Radikal and its DC motor.
* the Keel - which, because it is a one-piece subchassis/armboard combination, provides a rigid connection between the two which enables the stylus to extract far more low-level detail from the grooves. (This low-level detail gets lost by the "lossy" connection between the original pressed-steel subchassis and armboard, which uses those 3 little screws).
And from 3rd parties over the years we have had:
* the Cetech CF-composite subchassis in about 2000.
* the Sole aluminium/MDF-composite subchassis in the late 2000s.
* very new is the RubiKon subchassis/armboard.
* plus one or two other subchassis.
We have also had beautiful looking plinths made from exotic woods by a Dutchman called Henk (who I believe has ceased business?) and, still current, Chris Harban in the US. These are "standard" plinths but the mechanical properties of some of the woods make plinths made from them sound better than those made from other woods.
My proposition, for anyone who feels like repeating my experiment
, is that the mechanical properties of the plinth can be improved by a different method of construction. (The reason why Linn don't do this is that it would make the plinth a lot more expensive. 
)A standard plinth is made from planks which are about 23mm thick and the top-plate is supported by 6mm strips, fixed to the inside of the plinth on 3 sides. The vibration flow from top-plate to plinth is thus:
* from top-plate to supporting strip, then
* from supporting strip into the plinth, proper.
My proposition is that the energy flow will be improved if the planks which make up the plinth are increased to 30mm thick ... and a 7mm rebate is made on the inside edges of the plinth, to allow the top-plate to sit directly on the plinth sides. IE. the "two-step" energy path in a standard plinth (top-plate to strip to plinth) becomes "one-step".
This rebate is obviously only as deep as the thickness of the top-plate but it needs to be deepened to 20mm around the armboard, to allow clearance.
After thinking about this for a year or two, I was able to find a furniture maker who could make up a plinth like this. The result, I am delighted to say, is that the new plinth provides a much more controlled bass for my LP12 (in particular, some of my Bob Marley LPs had, with my particular phono stage, a very loose bass; now, the bass stops and doesn't "overhang" like it used to - if that makes any sense!
). And the soundstage increased in width - which was unexpected.Regards,
Andy
