The Clearaudio Unify specs show a 9 gram effective mass.
It is a unipivot.
The OL Silver specs show a 13.5 gram effective mass.
It is a gimbal-bearing arm with good quality bearings.
The Shelter 501 is a low compliance cartridge, with a 9cu compliance rating.
With the info posted above, I would say that when matching a tonearm to the Shelter 501 cartridge, the OL Silver tonearm has a better set of matching characteristics than the Clearaudio Unify.
I saw a post on Vinyl Asylum long time back wherein the inmate had cut & paste a response from Mark Baker that said that the OL Silver had an eff. mass of 17 gms.
I did some calc. with this eff mass # to calc. resonance freq & then I checked my cals. with the Hi-Fi News test record & my calc. were spot on.
Just FYI. However, I could be wrong. FWIW.
Twl certainly knows what he's talking about when he speaks of matching mass to compliance, but the formula is not that simple. It is the total system mass - cartridge mass plus tonearm mass - which must be calculated in the formula, not just the tonearm mass alone. Given this, the mass matching may work in the Unify tonearm. For a quick way of figuring this out, go to http://www.vandenhul.com/artpap/phono_faq.htm#a2, which provides a convenient graph to simply add the mass of cartridge and tonearm and match it against compliance.
I personally own the lowest-compliance cartridge ever made - a Decca - and I can safely say that the Decca will always work better in a unipivot tonearm than in any other, mass matching issues aside. I'm actually a fan of unipivots, as it was a cheap unipivot which first beat my modded Rega which I championed for years. This type of tonearm, while fidgety, always sounds lucid and musical. The "wobbly" issue is never a roblem in practice, as the arm stabilizes within a very short time once the cartridge descends into the groove. If you like the Unify, for whatever reason, then take a chance, it looks like a very good deal. If in checking out mass loading you find a bad case of mismatching, then there are other reasonably-priced unipivots out there, including a Kuzma and an Audiomeca (which advertises on this site). Any other fans of unipivots out there?
I don't know anyone who's tried a Shelter on a Unify, so the following is my attempt at deductive reasoning. ;)
Several people both here and on VA have tried a Shelter on other unipivots. Of those, Graham 2.x users seem happiest and Spacearm users are okay too. Many VPI 10.5/12.5 users are satisfied, but I know of two who cannot track the Teldec 1812 cannons (at all) and have trouble on the HFN record too. Users of some other unipivots have been even less succesful, particularly low mass, undamped unipivots. Some of these arms just could not handle the energy a Shelter can feed back into an arm. They ended up switching arms or going to a higher compliance cartridge.
OTOH and AFAIK, no one has ever been dis-satisfied with a Shelter on a Silver or higher OL arm. I may be biased because that's what I use, but I have some evidence for deducing that the Silver is the better choice. OOTB, the Silver has greater stability than any unipivot, just by virtue of its dual gimbal design. And OOTB it works quite well with a Shelter. However, the Silver can be easily modded for even greater stability with a little invention of Twl's. The differences this mod makes in bass response and control during dynamic passages are quite amazing, and would be instantly audible to anyone.
Conclusion: if the performance of an already stable arm can be so dramatically enhanced by increasing its stability still further, it's unlikely that an inherently less stable arm would be suitable. Just my $.02, hope it helps you think through your decision.
I have a Shelter 901 mounted on an OL Silver arm and I am very happy with the combination. Just be careful of a fully suspended table if you do not have adequate isolation.
Johnnantais, thanks for your comments. I expected that he knew the mass of the cartridge that he was planning to use. I certainly am aware of it, since I use that cartridge on an OL Silver tonearm, on a Teres turntable.
While I can understand your liking of unipivot tonearms, I would be careful about applying that to this particular set of choices in question. The cartridge in question is not a Decca.
Here my ignorance shows: can an arm's effective mass be enhanced by adding weight at key points on the arm and/or headshell? (and therefore work with lower compliance cartridges?)
It's refreshing to hear from somebody who is so aware of the realities of physics in analogue: mass matching seems to be something of a forgotten art these days. This being so, I thought that some clarification of your point was necessary for Joeljoel, to wit, that the cartridge mass must be added to the tonearm mass to come to a total system mass for the calculation to be meaningful. Just because jj knows the mass of his cartridge, doesn't mean he knows to add this mass to the mass of the tonearm (no slight intended to jj).
The point concerning my Decca is that the Shelter is a low-compliance cartridge, and for this reason feeds a lot of energy back into the tonearm, as Dougdeacon noted. The Decca is the lowest compliance cartridge made, thus feeds back the most energy, and so provides an example in practice of unipivot/low-compliance matching (the Decca is a bitch to match to anything). Dougdeacon provides the most relevant information of all, actual examples of such matching with a variety of unipivots. Since jj seems to favour the unipivot (I know not why), then I thought I would encourage him, I have no agenda, and actively use a variety of tonearms, including a modded Rega, a knife-edge bearing, an air-bearing, and so on. Had he favoured the modded Rega, then I would have told him of my good experiences here.
I would add something to Dougdeacon's detailed expose, however, that very few combos can track the cannons, and the HFN testrecord is increasingly considered as an unrealistic test of a cartridge-tonearm combo. In practice, "real-world" records, which is to say regular commercial pressings, rarely present a problem. But nothing is perfect. To get back to my Decca (only one of my many cartridges), there are quite a few things it will not track well (except in one tonearm I have tried), but I love the sound and so learn to live with it. It's just plain a blast to listen to. For this reason, I keep other cartridges around, like the track-everything Shure V15. Perhaps jj just wants to have fun, too. But the Shelter should be quite a lot easier to live with than my Decca.
By the way, in getting back to the person who is asking for the advice, why do you lean towards the Unify, Joeljoel?
Joel, yes you can do that, but it has its drawbacks too. Most methods like tonearm wraps will add mass, but will do it in both planes of motion. It is desireable to have lower mass in the vertical plane for good warp tracking, but desireable to have higher mass in the horizontal plane for better cartridge stability. The amount needed will vary, depending upon the other factors involved.
Additionally, the added mass may solve the mass/resonance need, but does nothing for the stability problem regarding unstabilized unipivots and low compliance cartridges.
John, nice response.
I have been around on these analog pages for awhile. You might have noticed some of my other posts. I actually have done some tonearm mods(called the HiFi) and made them available to the members, and have designed some turntables and tonearms that are destined for market in the future.
I do some analog design and other design work for a fairly well known audio company.
Thanks for all your responses. As to why I am leaning toward the Unify - it is quite simple, I have found one which may come in a bit cheaper than the OL Silver. Also, I am not crazy about the plastic base of the Silver (i.e. I find the esthetics of the Unify more pleasing [a lame concern, I know]). After your input, I may be pursuing the Silver instead. . .
Thanks for the kind references. I don't have your broad personal experience with arms and cartridges, but I certainly believe you that very few combos can track those silly cannons. I imagine even fewer can do so and also display a high degree of musicality on real music (of which that particular record contains exactly zero.)
My limited personal experience, however, has discovered at least one combo that can do both. My Shelter 901 on a Twl-modded OL Silver blasts through the cannons with no undue excitement or gymnastics, yet plays music that will break your heart. I'm only guessing that a 501mkII on the same arm might perform similarly, perhaps with slightly less bass response and top end detail.
I totally agree that the HFN record is of marginal utility for setting up good combos, but I think it's pretty good at showing up bad ones. If a combo does especially poorly on fairly simple test tracks, I'd worry about how it might handle the far more complex problems presented by real records.
Nothing lame about aesthetics. We both fell for the Teres 265 and I'm certainly not ashamed of that! A Moerch DP6 or Basis Vector might answer all our concerns, but not at a price you or I could stomach.
I agree the OL arms look pretty humble, even humbler with Twl's goofy-lookin' HIFI Mod stickin' outta the sides. (Just kidding Tom, I post referrals every week.)
Here's how to get around the look: cue up a good record and watch your friends faces. Trust me, they won't care or even notice what anything looks like. The normal response is closer to that of the great Art Dudley, "Holy mother of crap!"
You certainly have a point with respect to exposing bad matches. I have, actually, a collection of test records which were issued over the years, including a couple of Shures. The music on most of these is quite good! But though I should know better, I usually just stick whatever new cartridge I have onto an arm and "suck it and see," as the Brits say. Call me curious George, an inveterate tinkerer.
I can see that there's a lot of experience with the Shelter/OL tonearm, and it seems like the best bet for Joel. But a liking for aesthetics enhances one's enjoyment of a particular piece, pride of ownership and all that, and I'd hate to see Joel give up on it without giving it a chance...is there a mismatch in terms of mass/compliance?
The Shelter cartridges actually sound quite interesting: I'm always attracted to controversy, which why I bought my first Rega arm in the '80s. It seems to me that controversy is a sure sign of something good. Which is why I own a Decca as well. Perhaps I should buy a Shelter for the collection. If I do, I can thank Joel for introducing the idea.
Good luck to everyone in their search for audio nirvana and good old-fashioned fun, let's not forget...
Totally agree on the value of aesthetics. If I had the funds I'd probably get a Basis Vector. That arm certainly satisfies in aesthetics/BQ and seems to have suitable engineering to handle a Shelter or most any cartridge.
Even if the mass/compliance of a Shelter/Unify is perfect, it will never have the higher lateral inertia of an OL Illustrious, Encounter or modded Silver. In my system, high lateral inertia in the arm is essential to attain the deep, controlled bass and extraordinary dynamics that a Shelter 901 is capable of. Silver users with the 501mkII report similar results. YMMV in the end of course.
Hmmmm...This Shelter sounds more and more like my Decca: I'll but a Shelter if you buy a Decca! Just kidding, anyway, as I wrote, whatever the rewards, the Decca is a bitch, but some would say that's half the fun!...no pain, no gain...I'll probably buy a Shelter anyway, though I have a list...Cheers.