Sme arm "Bridge Removal"

Could someone explain to me what "loading" the bearing means? And how having the bridge in place, or not, affects that "loading"?

Yesterday, I removed the bridge on my SME V, and to me, it looks simply bolted to the main tonearm yoke casting. The attachment bolts themselves do not appear to do anything more than simply hold the bridge in place (they do not hold the bearing in place!) -- and tightening them wouldn't do anything more than hold the bridge tighter and tighter until you snap the bolts! There does not appear any way that tightening (or loosening) these bolts affects the the tonearm's vertical bearing, which is already press-fit into the main yoke casting and would not be affected by the presence or absence of the bridge.

Having the bridge in place completes the gimbel design look of the mechanism, and IN THEORY would keep the top of the main casting from spreading apart, perhaps with slight variations in temperature; but such microscopic changes are, it seems to me of little consequence, and in any case, do not affect the built-in "tightness" of the bearing (if that's what is meant by loading?)

Nsgarch,
...technical issues aside, tell me did you like the change in sound?

Dear Neil,
I suppose that 'loading the bearings' is the same thing that Dertonarm refers to as 'pre-tension of the bearings' in the following (which,incidentally, is the explanation that convinced me to go ahead with the application of damping):
"While all done and designed in the best intention [= the SME V design],the shape of the magnesium armpipe with the widest diameter at the bearing does somehow amplify and ill-control armwand inherent resonance. The heavy pre-tension of the bearings doesn't ease things in this manner at all."
[http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1266367593&openflup&142&4#142]
I suppose that what he is referring to is the degree of tightness of the bearings in their sockets.
Exactly what the role of the bridge is in all this, I am not so sure. As you say, it is simply bolted to the yoke. When I decided to remove it (a long time before applying the external damping), I did so on the simple (and perhaps simple-minded) basis that it was just a cosmetic element (and in fact the arm does look better with it in place) which could resonate and degrade the sound to some small degree (after all there those who remove the fluidd damping trough for the same reason). Its cosmetic nature appeared to be confirmed by SME, who assured me that it played no structural role in the design and could be removed without untoward consequences.
Best regards,
Peter

Sme10 - I did not hear any of the changes you and others have reported. Frankly, if I did, I would would be more alarmed than pleased. But I'm still very anxious to understand what this "loading" terminology refers to, and hope someone will explain it.

Thanks.

Neil
.

The bridge removal was recommended by Roy Gregory in one of the early issues of HiFi+, for all of the reasons mentioned above. I do not believe there was any mention of bearing tensioning, although he did mention that you need to be careful not to overtighten when putting it back on in order to avoid deforming the cradle, thereby affecting the free movement of the bearing. I tried it on my SME IV, but I didn't feel comfortable leaving it that way. Although I "thought" I could hear a difference, my recollection is that it was not great enough to warrant marring the beauty of the arm. On the other hand, that was a long time ago, and some of my components, including my TT, have changed since then. I haven't thought about this in several years -- maybe I'll try it again and report back.

Enjoy!

Neil (no relation to the other Neil)