I thought about the 'shoe box' argument by convertible cars
wich causes the lesser rigidity of those cars. Per analogy
the bridge my have some influence on the arm rigidity. However I have no idea about the 'forces' involved.
Regards, |
I think it really depends on your table. If you need the sound to be more airy then the bridge removal does help. But if that is not what you are looking for, then leave it on. It certainly does look better with the bridge. But there is a difference in sound. I like what I heard but in my system I did not really need the change. |
I have to agree with Rccc on this one. I tried it again and, to me, removing the bridge didn't change anything, except the looks of the arm. SME is not the kind of company that would continue to market a product for all of these years without remedying what would have to be characterized as an obvious design flaw (if, in fact, the bridge degraded the sound). That being said, SME have stuck with that van den Hul phono cable for all of these years and, although I think that it is the quietest cable around (perhaps because of its triple point grounding scheme), I have been able to better it in almost every other way with a variety of aftermarket cables, most recently the Harmonic Technology Crystal Silver Phono. I wonder why they have never adressed this cable issue. Is it just a cost thing, or do they really want the arm to sound the way it sounds with the van den Hul MC D501? |
I have an SME V that I bought used here on a-gon with a wiring "upgrade?" sans head shell clips and the anti skate defeated. I went all the way and took off the bridge and listened this way for seversl years with a variety of carts and pres. Recently I sent it back to SME for a complete rebuild . It was returned to me as a brand new current spec V (bridge in place). The arm has never sounded better and I have no intention of modifying it in any way again. It seems to me if these tweaks were genuine improvements SME would have incorporated them over time into their current spec. |
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) |
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
. |
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 |
Nsgarch,
...technical issues aside, tell me did you like the change in sound? |
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?) |
I have had an SME V in my system for numerous years now. I have modified it in the following ways:
1. changed external wiring first to Cardus and then to Siltech Avondale;
2. changed internal wiring first to Van den Hul MCS 150, and then to Kondo;
3. removed the bridge;
4. applied very small amounts of damping material (in fact a sort of adhesive putty very similar to Blutack) externally to the armtube at certain key points (near the bearings, near the headshell).
When the arm was sent to SME for the second rewiring it was already without the bridge. SME did the job without demur and returned the arm without replacing the bridge. On the phone they said that they had seen a number of arms modified in this way (they simply warned me to take care - should I one day decide to replace the bridge - not to tighten the screws too firmly : apparently this could damage the bearings).
The following well-known modification I decided to forego:
5. bypassing the headshell clips and running a single length of internal wiring from the cartridge clips to the five pin connector in the base.
I abandoned this idea on advice from SME and others (Definitive Audio, UK): the more delicate the internal wiring, the greater the likelihood of breaking one of the strands while changing cartridges.
The application of the damping material was done on the basis of advice received in this forum (Dertonarm, who I thank). There are also posts on Vinyl Asylum that recommend this. I experimented quite a bit, varying the amount of the material and the position. I ended up rolling it out in order to reduce the thickness and obtain the best extension for a given weight of material (I doubt if the total amount I used was greater than a small pea). Once applied it can easily be coloured with a black felt-tip pen, thus reducing (but not completely masking) the undesirable aesthetic impact. Of course, downforce has to be adjusted after application.
The more recent of the above modifications - the change to Kondo internal wiring, the removal of the bridge and the application of external damping - have all (in my opinion) contributed to increase the neutrality of the arm. The playback I am getting now is more relaxed, more airy and richer in tone colours and in spatial definition than it was before (cartridge: Benz Ruby II, retipped and modified by Roberto Torlai. Turntable: SME 30/2).
Best wishes. |
|
Hello Guys,
have removed my bridge...
And after a good few months, can conclude it is a vast improvement (at least to my ears).
The treble extesion is increased, and there is a more liquid feel to the presentaion.
It really is quite a change, and highly recomend one trying it.
Cheers |
James,
as far as I know, there are no adverse effects when trying the Bridge Removal. You can remove the bridge, then reinstall it, and as a bonus, you have relieved some pressure from the vertical bearings (yes, those are for up and down movements of the armwand). There is enough bearing preload in the SME V tonearm, so you need not fear of bearing play.
best regards, Hartmut |
After reading all the discussion I could find on AA, the overwhelming consensus seem to fall into the "no difference" or "very little difference" results. Maybe different cartridges respond to the alteration differently? Personally, I prefer to avoid that twilight zone ;-)
I also find the "totally cosmetic" response from SME confusing: if it's totally cosmetic, why so much caution about getting the torque on the bolts just right, etc.?
I wish I could understand better the relationship between this 'bridge' and the vertical(?) bearing (would that be the one that sits crosswise and allows the arm to move up and down?) before I try this tweak; perhaps SME would issue proper instructions for this procedure if requested?
. |
No need to worry about removing the bridge. I have spoken to SME about this and it is totally cosmetic. However I have tried it and prefer the sound with it in place.
Jonathan UK |
James, I've heard about this to. I have been way to chicken to try it. Even loosening the screws make's me a little queesy... |
Hello Hartmut,
Thanks for the info, ideed this is the bridge!
Do you know if toying with the bearing presure can bring about adverse affects?
Or can one remove the bridge and replace it with caution, but with out serious risk?
A few guys over on vinylasylum raved over this tweak..
Also Kevin @ http://www.definitiveaudio.co.uk/ recomends this, check the pics.
Thanks
James |
Hartmut -- could you please explain what 'preload' means (in terms of the mechanism itself.) Sounds interesting.
. |
Dear Hartmut: Thank you for your info, everyday is a learning one.
Regards and enjoy the music.
Raul. |
The Bridge Removal indeed refers to the brigde across the main bearing.
To understand why this has a sonic effect, one should know that the bearings are preloaded very high with SME IV,V,309 tonearms (and their siblings). And then the vertical bearing is very sensitive sonically, a lot more than than the horizontal bearing, in my experience. If you remove this bridge, you lower the preload, and thus gain treble air and lose some harshness. But, at the same time, you lose some bass power. From what I have tried, it is best to losen the screws of the bridge, then retighten it again. With this you lower the preload, but don't lose much bass power.
best regards, Hartmut |
Dear Sme10: If " bridge removal " is a synonymous of finger lift then I agree that the IV/V/cartridge performance improve a little maybe due that the " connection " between the tonearm and the cartridge is more direct.
Regards and enjoy the music.
Raul. |
I never installed my SME V fingerlift. I have not done an a/b listening comparison, but I figure it is one more thing at the headshell that can vibrate. I simply move the headshell into the right location and then slowly lower it using the damped arm-lever/lift. Very simple with no fear of damaging the cantilever. I prefer the fixed headshell for the same theoretical reason, though azimuth now needs to be adjusted by slightly tilting the base of the arm before tightening the set screws. Works fine, but is less convenient. Also can't easily swap cartridges. |
I HOPE you're talking about the "finger lift" and not the bridge across the main bearing!!
It's true there are some who assert better performance w/o the fingerlift. "But ask yourself this *punk, are ya feelin' lucky!?" (I say be nice to your cartridge's cantilever ;-)
* reference to Clint Eastwood in "Dirty Harry". No offense intended, just couldn't resist ;-)
. |
