2. analog
  3. 188395-72

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!

wrm57
dover
2,262 posts
 

@wrm57 

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.

 

 

 

 

 

wrm57 OP
1,057 posts
 

@dover , good info, thanks. 

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rauliruegas
13,103 posts
 

Dear @wrm57  : Ikeda opinion it's  only that an opinion and that's all.  There is no brittle and it's not true that the EPA 100 is not for low compliance. Again , Technics makes that kind of mistakes.

The EPA 100 comliance cartridge range it its counterweigth wise mechanism says in the tonearm manual from 5cu and I had first hand experiences with the EPA 100 and several low com'liance japanese cartridges with outr any single trouble.

In the other side, my advise is that you go step by step with your tonearm and for me first step is th internal re-wiring that you could do it with Audio Note UK silver wire that's excellent.

Then listen it for a while and decide if in true the tonearm needs a bearing change: don't change what is in good operation, remember?

 

R.

wrm57 OP
1,057 posts
 

That's good advice, @rauliruegas. Much appreciated.

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