general tonearm design question


Many popular tonearms are designed with with the fulcrum for the vertical axis at ~70 degrees (e.g. Rega, SME), rather than perpendicular (e.g Origin Live).

Doesn't the former design cause the needle to track to the outer groove as the counter weight swings downward?

...or does the cartidge/tube somehow counter this?

Would a counter weight mounted at 90 degrees to the fulcrum, yet the arm tube set at 70 degrees be the solution to this, or am I wrong?

(The reason I started wondering about this was due to the varous Rega counter-weight mods. I would think that a lower center of gravity would exacerbate this problem. Furthermore, wouldn't a lower center of gravity only be effective on a uni-pivot design?)

your thoughts?
popluhv

Showing 4 responses by sirspeedy70680e509

Both responses are superb,but I feel a sense of obligation to like Doug's better! -:)
Best!
Doug,truthfully I don't hear anything in my friend's Phantom/Orpheus combo to make me want to change arms!Of course we have not done a side by side comparison,but I installed the Orpheus in his 2.2,and a dealer did it when the Phantom came( I know his system like my own).I,then,re-checked and voiced it to a more acceptable(to our circle of guys)level of performance.The Phantom is superb,but you are WAY underselling the 2.2!Old story,but NO problemo!!-:)
The Orpheus IS another story!I definitely like it WAY better than the Temper-v,which he had(I still do,but need more hours to justify a change).
Mind you,I really don't have much enthusiasm for the hyper technical(though I have NO reason to doubt your theories,which are usually well thought out,btw)comparisons,to prove something on paper.This does NOT mean you are not absolutely correct,but my 2.2(especially after the NEW Power Management System)is "really" giving me incredible performance!Could care less about the magnaglide as my arm NEVER tilts/rocks during play(really).I sense just a bit more air in the 2.2,with more weight in the Phantom(sort of like the superb SME-V,here).

I DO know what my Mercs,Lyritas,Deccas etc should sound like,and believe me if a unipivot sounded anything less than superb my friend Sid Marks,the LP maven(in spades) would never have sold his Air Tangent,and replaced it with a Unipivot design.Though I definitely liked the AT better.If there was a problem in my tracking,he would "destroy" me,and it is his dogged critical nature that has rubbed off on me,and gotten me in trouble on this site.Yet you are being a bit too picky,and trust me,I know not to tread too heavily with you,here!The performances,with all the other variables in place are really NOT all that big.
For that matter,the argument made by the reviewer,talking up this new arm called the SEPTUM(see the TNT website)has as much credibility,for "low parts count" as your argument against unipivots.He writes a very engaging design description,that makes alot of sense to me,but I am getting way to long in the tooth to argue anymore.My 2.2 is admittedly VERY finicky to set-up(that fluid again).Way more-so than the Phantom,which is less critical to fluid,but I like the latitude available(at least to me)with the 2.2's flexing of parameters.That is JUST me.Meaningless to anyone else!
I do have superb aftermarket cords on the EP stuff.The 15a came after the balanced Ultrapure,but it greatly enhanced the Ultra's performance.I am a big believer in fully balanced,so I never went the other way.INCREDIBLE combination!!!!!
Well,thanks for the communication,and best to you.
Don't worry,Doug.No problemo.Feel free to mention the 2.2,it really would be silly for me,or anyone to get offended by a product comment.So long as the product sounds good,I don't care.The past is an embarrassment to me,so don't sweat whatever you feel like saying,at any time!!
My friend just got the Phantom,and it is superb.Being that we both have "flat platters",at all times,due to vacuum,the issue of the "true" unipivot 2.2 does not seem to be a big deal to me.I never see any twisting movement of sideweights when playing LP's.Yet,I think the Phantom is fabulous.It has it's own idiosyncrocies though!
BTW,yes,the Triplanar is not so bad either.-:)
Best!
Doug,I honestly don't know of "any" unipivot that relies on stylus/groovewall and cantilever/suspension pressure to help maintain steady azimuth,or balancing.That,alone,would be poor design,and would surely put a "TON" of pressure on the stylus/suspension.Who knows?Maybe I have more to learn,but I don't think my arm,or my friend's VPI rely on this.
They sure sound good though! -:)
BTW,without you knowing it,I am reporting that your EP-15a listing(Nsgarsh too) aided me in getting one!I included the Exact Power Ultra-Pure to go fully balanced.THIS combo is the the biggest improvement I have made to my system in a long while!Stuff like vta/azimuth/downforce changes are WAY more obvious with super clean A/C,and I'll bet many folks don't know how much more can be had!
Best regards!