'Has anyone compared the sound of Si3N4 bearings to the original ruby?"
Drag coefficient has a sound?
Which EPA-100 bearings?
I picked up a nice EPA-100 a few months ago in excellent cosmetic and functional condition. The bearings seem good, as far as I can tell—it passes the WallySkater stiction test with aplomb, anyway. And it sounds remarkably alive and resolving with no obvious behavioral issues.
Still, given the famous fragility of its ruby bearings and the age of its internal wiring, I suspect it can sound even better with some refurbishment—new bearings, new wiring, whatever it needs. I think this tonearm is good enough to warranty the investment.
JP at Fidelis Analog has graciously agreed to work on it. He offers, and prefers, silicon nitride ceramic bearings (Si3N4) for both performance and longevity. He also has a supply of ruby bearings for those who prefer to keep it original. So, I have a decision to make. I like the idea of keeping it stock but I want the best performance and, most important, sound.
Has anyone compared the sound of Si3N4 bearings to the original ruby? Has anyone replaced the ruby with Si3N4 and regretted it? I’d like to hear some hands-on, ears-on experience before I make the choice.
Thanks!
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Ruby's and Sapphire are fragile and may be difficult to ensure the parts produced from it in a Tonearm or TT, will be intact at the end of a Long Freight Journey. Si3N4 is commonly seen used as a bearing in place of a Steel Ball, the Si3N4 is known for its robustness, and is seen at interfaces where impact damage is a risk. https://forum.audiogon.com/discussions/silicon-nitride-vs-ruby-bearing-for-rega-p5
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@pindac , thank you for those links. Very interesting, especially moisin’s comments. @rauliruegas , I appreciate your experience in this matter, as in others analog. Is it that you think the ruby material (actually sapphire, as it turns out) has a preferable sound to the Si3N4? I ask because the hardness and density of the two materials seem virtually the same, which means their friction and stiction will be pretty close to each other when the bearings are unflawed, which means their mechanical performance should be pretty much the same. So what’s left? Whence your strong preference for ruby?
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my understanding is the silicon nitride bearings produced today have a far truer surface ( in terms of roundness ). In terms of sound - Isamu Ikeda ( Fidelity Research, Ikeda ) always eschewed the use of jewelled bearings, describing the sound as brittle, but bear in mind his cartridges are low compliance and demand very good bearings. Having said that I would not recommend very low compliance cartridges be used in the EPA100. The top Technics cartridges of the day were medium to high compliance. In my view its a no brainer - if it were my arm I'd install silicon nitride bearings. JCarr has replaced the bearings in his own EPA100 with silicon nitride.
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@dover , good info, thanks. |
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