Silicon Nitride vs Ruby bearing for Rega P5


I upgraded my P5 last year with a groovetracer subplatter and ruby bearing for an improvement my wife called "shocking". I've now come across the silicon nitride bearing and have one in hand. I'm reluctant to turn the TT upside down, swab out the well, etc. if the change of bearing isn't going to provide audible improvement. Anyone try this before? Will appreciate your thoughts.........
joe_in_seattle

Showing 2 responses by frank_sm

This is very interesting indeed. Let's analyze the facts regarding mass and hardness. Ruby/Sapphire has a density of 3.98G/CM3 whereas Silicon Nitride has a density of 3.44G/CM3, see a very close resemblence here?
On the MOHS scale (hardness) sapphire is 9, second only to diamond, whereas Silicon Nitride is 7.5, slightly softer in comparison. These 2 materials are so similar in density and hardness that IT is hard to believe anyone can discern a difference, especially given the small size bearing we are talking about here (3/16" dia).
I experimented with Silicon Nitride several years ago and since then I've been reading of massive claims of sonic benefit over a ruby or sapphire bearing. If you can hear a difference, brilliant, however I heard no difference at all. This is one of the overblown audiophile observations going, RE. bearings.
Your quote speaks of a totally different application. A CMM (Coordinate measuring machine) is not a turntable. The probe of a CMM comes in contact with many types of surfaces, some not as smooth as the thrust surface of a turntable. What abrasive surface are we talking about when it comes to a turntable bearing?
Can you add real life experience of your own regarding these bearings in turntable use?