Folks interested in this tweak may find value and similarity in perusing the Audio Basics article from around 1985 by Frank Van Alstine for his Grado Longhorn stabilizer. I have used it for years on Grados and then abandoned it when I bought a Platinum. Then a few years ago when I got a Shelter 501, I decided to trial fit one and am sold on it again.
Strange Tonearm Tweak. Long
As you all know, I am a little different. I like to read and study stuff like tonearm technology. I noticed that some of the better unipivot designs have employed "outrigger" style outboard weighting systems on their arms, that work like a tightrope-walker's balance pole. This not only balances azimuth, but also gives the arm better stability to lateral deflections from the cartridge suspension, so the arm is not moved when the stylus is pushed laterally by the groove information. I began to think on this, and I wondered why no gimbal-bearing arm makers are doing this. Surely since the vertical plane rides on a vertical axis bearing, there is still some chance for the arm to be laterally deflected by the stylus, when the stylus should be doing all of the moving, not the arm. I think that this is why they use heavy arms, but a heavy arm in the vertical movement plane is not good for tracking. A heavy arm in the horizontal movement plane is good for resisting sideways deflection that would impair pickup function.
So I decided to try increasing the mass of my tonearm in the lateral plane, while keeping it light in the vertical plane, by the use of "outrigger" weights, just like a unipivot does.
I bought lead fishing weights that looked like long rifle bullets(just the lead part) They were about an inch long and about 3/8" diameter, and weighed 12 grams each. I drilled into the bases about 1/4" and press-fitted them onto the nuts that hold the arm into the bearing yoke, so they stuck out straight sideways, like sideways spikes. This put the weight out pretty far to the sides as outriggers, and kept the weight centered exactly around the bearing pivot axis so it did not increase the vertical mass significantly, but it did very slightly. It did not influence the tracking force at all.
So now the arm had outrigger stabilizers on it in the horizontal plane of motion.
I put on a record and sat down to listen. Let me tell you, fellas, this was a mind blower. I have never heard this much information come out of a cartridge before. I heard sounds on records that I had listened to for 30 years, and never knew those sounds were on the record! And I have had some pretty good analog gear in my time. And what I didn't own, I heard at the audio store I worked at. This is the most astounding mod I have ever heard on a tonearm. And it cost me $1.49 for the fishing weights, and I got 3 extras.
The only slightly negative thing about it, is that it increases the anti-skating force, so you have to cut that back a little, and if you have some marginal scratches that might skip, they are more likely to skip with this mod, due to the resistance to sideways movement provided by the outriggers. I had this happen once last night, but I didn't consider it a problem.
But the increase in dynamics, and detail and overall sound quality is astronomical. It blew me away.
I have a DL103, which is a very stiff cartridge, and it may be that this is not needed for a higher compliance cart. But, I think that it would be good for anything that is medium or lower in compliance.
The key to it, is that it only increases the resistance to sideways movement, without interfering with the effective mass of the arm, or the vertical swing movement that needs to stay light to track warps. I played some warped records with this mod, and they played just as well as without the mod, except they sounded better.
I have a pretty good analog setup now, but I can say without reservation, that this mod made my rig sound better than any analog rig that I have ever heard in my life. I have never heard a Rockport.
Stabilizing the arm against unwanted lateral deflection increases the information retrieval and dynamics by a very large percentage. If your arm is not set up like a Rega style arm, then you can glue a 1 ounce long rod across the top of the bearing housing(sideways) like a tightrope-walker's balance pole. Use lead if you can, it won't ring. You don't have to do any permanent changes to your arm that might wreck its resale value to try this out. If it has anywhere near the effect on your system as it had on mine, you won't be taking it off.
It may come close to the movement of your cueing lever, so make sure you have clearance to use it. Mine was close, and I have to come in from the side now to use the lever, at the end of a record. That is fine with me! This was a major, major improvement in the sound of my rig. It is staying permanently. As in "forever".
If you are a little tweak-oriented, and not afraid to do stuff like this. You should try it. It will knock you over.
So I decided to try increasing the mass of my tonearm in the lateral plane, while keeping it light in the vertical plane, by the use of "outrigger" weights, just like a unipivot does.
I bought lead fishing weights that looked like long rifle bullets(just the lead part) They were about an inch long and about 3/8" diameter, and weighed 12 grams each. I drilled into the bases about 1/4" and press-fitted them onto the nuts that hold the arm into the bearing yoke, so they stuck out straight sideways, like sideways spikes. This put the weight out pretty far to the sides as outriggers, and kept the weight centered exactly around the bearing pivot axis so it did not increase the vertical mass significantly, but it did very slightly. It did not influence the tracking force at all.
So now the arm had outrigger stabilizers on it in the horizontal plane of motion.
I put on a record and sat down to listen. Let me tell you, fellas, this was a mind blower. I have never heard this much information come out of a cartridge before. I heard sounds on records that I had listened to for 30 years, and never knew those sounds were on the record! And I have had some pretty good analog gear in my time. And what I didn't own, I heard at the audio store I worked at. This is the most astounding mod I have ever heard on a tonearm. And it cost me $1.49 for the fishing weights, and I got 3 extras.
The only slightly negative thing about it, is that it increases the anti-skating force, so you have to cut that back a little, and if you have some marginal scratches that might skip, they are more likely to skip with this mod, due to the resistance to sideways movement provided by the outriggers. I had this happen once last night, but I didn't consider it a problem.
But the increase in dynamics, and detail and overall sound quality is astronomical. It blew me away.
I have a DL103, which is a very stiff cartridge, and it may be that this is not needed for a higher compliance cart. But, I think that it would be good for anything that is medium or lower in compliance.
The key to it, is that it only increases the resistance to sideways movement, without interfering with the effective mass of the arm, or the vertical swing movement that needs to stay light to track warps. I played some warped records with this mod, and they played just as well as without the mod, except they sounded better.
I have a pretty good analog setup now, but I can say without reservation, that this mod made my rig sound better than any analog rig that I have ever heard in my life. I have never heard a Rockport.
Stabilizing the arm against unwanted lateral deflection increases the information retrieval and dynamics by a very large percentage. If your arm is not set up like a Rega style arm, then you can glue a 1 ounce long rod across the top of the bearing housing(sideways) like a tightrope-walker's balance pole. Use lead if you can, it won't ring. You don't have to do any permanent changes to your arm that might wreck its resale value to try this out. If it has anywhere near the effect on your system as it had on mine, you won't be taking it off.
It may come close to the movement of your cueing lever, so make sure you have clearance to use it. Mine was close, and I have to come in from the side now to use the lever, at the end of a record. That is fine with me! This was a major, major improvement in the sound of my rig. It is staying permanently. As in "forever".
If you are a little tweak-oriented, and not afraid to do stuff like this. You should try it. It will knock you over.
269 responses Add your response
Anyone with a rega based arm should try this tweak. It costs about $1.50 and takes about 30 minutes to do assuming you have an electric drill and the right size bit and some mechanical ability. I had been struggling for about 3 months trying to get my vinyl to sound as good as I thought it could. I read everything used every free online protractor but still wasn't satisfied with the quality of the music I was hearing. I implemented TWL's tweak 3 days ago and the improvement was amazing, everything finally snapped into place, even the inner grove distortion I have been struggling with is almost completely gone. With out a doubt the best most cost effective tweak I have ever used. Thanks TWL |
When I had the Rega arm, I noticed that unsing the spring to exert downward force for the cartridge pressure caused the spring to vibrate and cloud the sound on some frequencies. I simply didn't use it, set it to zero, and used the Expressimo weight forward of neutral balance. I used a Sure scale to measure the 1.8 grams I needed for the cartridge |
Your idea is not really new. Take a look at the VPI arm. There are 2 outrigger weights that are not there for azimuth adjustment..this is done by rotating a dropped counterweight. In truth the problem with this arm is that it is quite diffucult to set up since the rear weight effects azimuth, VTF, which also has an effect on VTA. After lots of careful adjustments, the arm is very good indeed I think the autrigger weights are there to increase mass in the horizontal plane as you suggest. |
IME with the HIFI mod on an OL Silver, the sonic improvements were entirely consistent with an increase in lateral moment of inertia. Bigger dynamics, stronger, tighter bass, faster transient response, etc. I do not recall much if any improvement in areas that I'd attribute to improved resonance damping. No greatly lowered noise floor, no big reduction in overly resonant notes, etc. I DID hear those things when I adopted Twl's suspended counterweight, which pretty much entirely decouples the c/w from the arm. That's another story though, and it's not easily used. Read through this whole thread if you dare. There's a lot of interesting material and experiences here. Taught me everything I know! Thanks again for the nth time to Twl for forging a path so many followed to better sound. |
I'm puzzled now. The additional lateral moment of inertia is really quite low on this tweak, so that can't be all the difference. Or can it? On the other hand, Twl has mentioned Coulombic friction, at which point it occurs to me the tweak should then work better on the OL Silver, with its exposed pivot, than on the unmolested RB250. Reasoning being, on the OL Silver the weights will damp out both the vertical and horizontal bearings, whereas on the RB250 without removing bearing covers the weights will only damp out the horizontal bearings. On the other other hand, Zero_one's tweak clearly only damps out the horizontal bearings (and how!) anyway... Unfortunately I can only speculate at this point because I have an arm, but no table yet... But all very interesting... |
Well this is my first post on this forum, made plenty on others though, I registered mainly because this thread struck a chord. I have long felt that the concept of damping in the horizontal plane is sound and some time back I tried a slightly similar idea. In my case along with a list of mods too long to go over I added a round weight over the top of the tone arm at the centre pivot, in my TT this works as there is a yoke that comes up and over the arm, so the weight sits on top of that and is actually an old video head. If you go to my webpage here http://homepage.mac.com/braddles/Menu2.html You will see what I mean. Anyhow I was attampting to do 2 things, one add more mass so as to make it more difficult for the arm to deflect in the horizontal plane in response to unwanted tracking movements and secondly to kill bearing chatter in what is a pretty rudimentary arm. Net result was that the sound was much improved, the bass much stronger and tighter and highs sweeter I would say due to the lower chatter levels. It may just be too that one of the reasons for the much improved sound others are experiencing with this type of mod is also reduced chatter as the bearing would be more stable in all directions when playing and I would say using the outrigger idea on this thread would be superior to mine in doing that. The mod talked about in this forum takes it to another level I would say and will try it. I feel there would be an optimum weight that would work and beyond that the damping too great so it would need careful assessing of just how much. This concept though is also related in essence to the idea of longhorn mods on carts, which is something I have found very effective on stiffish carts. If you have a look on my web page you will see a set of pics for my "waveclone 01" cart which I built up from a very cheap cart, it has an integrated longhorn mod. (note that this is quite a bit different to the usual implementation). The tracking with this cart is marvellously secure and it sounds way way better than it really should considering it started out as a $10.00 cart, so in I think stabilization at either end of the arm can be a good thing and they can probably work in very nicely with one another on stiff cart in basic old arms. |
Hi guys. It's been a long time, and I've been away from the site. I'm happy that some of you are finding out what this mod can bring to your music. Regarding the Townshend with the silicone damping trough, yes the damping is having a similar effect but in a different way. That is probably why the effect of the mod wasn't as noticeable in that case. Being that the silicone trough is up at the headshell area on that TT, the stabilizing effects will be nearly immediate in that case, but not quite immediate. That is likely why the TWL mod was still giving some benefit, but not as much as usual. I'm still getting a chuckle that after all these years, people are still finding out about this thing, and getting amazed by it. It's a very simple application of basic tonearm design, that seems to have eluded the tonearm manufacturers even to this day. Too bad I can't get rich off this idea. But, if people can enjoy better sound for next to nothing expended, I guess that is reward enough for me. And yes, the tungsten weights or other types of weights will work just fine. |
Thought I'd drop by. My Jelco arm (think MMT, Audioquest, Graham Robin)doesn't have the capability of pressure-fitted weights like the Rega. But on each side of the bearing housing I thought there might be room on the sides for something, small flat spots where bearing adjustment "screws" are located, so I thought some more for something that I could do fast. The arm is mounted to a restored Russco Mk V, with a DL103 cartridge. A few minutes later I glued six quarters into two groups of three, face to face, with a hot glue gun. Used the same hot glue to attach the quarters to the spots I referenced above. Totally reversible as the glue stays a bit soft after curing and peels off of metal with just a bit of effort. Shazam! The effect seems exactly as described in your initial post from five years ago. I may engineer something a little prettier in the future, but the 16.5 grams or so on each side (each quarter is 5.5 grams)works very well with this arm (and presumably variants of it like those mentioned above). I don't know if the greater weight (compared to the fishing weights) compensates for their shorter lateral reach (compared to the fishing weights), but that was my thought when gluing three quarters together instead of two. If anyone is curious I uploaded an image here--http://new.photos.yahoo.com/deanmanjames2003/album/576460762310128890 Comments, suggestions welcome! Jim |
mctigues, Have you tried listening without the silicone dampening engaged? Try this without and with the HIFI Mod. That would probably be a good test of your question. Personally, I have never liked the effect of silicone dampening (except on unipivots where the silicone sits directly around the bearing). On gimballed arms like your Silver and my TriPlanar, I much prefer the sound with no silicone in the trough at all. YMMV of course... Doug |
have an RB300 mounted on a Townshend Rock Mk. III. This turntable incorporates a damping trough at the cartridge. The trough is filled with a viscous silicone solution. An outrigger assembly is mounted at the headshell that has a paddle that runs through the viscous solution . The RB300 came from Townshend. It came with the tungsten CW w/ an additional weight epoxied to it to offset the added mass of the outrigger. The diameter of the hole on the additional weight is larger than the shaft. Its weight is being supported by the tungsten cw. I am using the latest Shelter 501. I applied the TWL mod last night with great anticipation only to find VERY minor appreciable effect. Perhaps a VERY SMALL increase in bass definition and weight. I am wondering if the trough of the Townshend is providing similar stability to that of the mod? Any thoughts would be appreciated. |
Hi Twl and all other major contributers in this thread. I'm about to buy a OL Silver MKII, and during my research I stumpled across this thread. It seems like you have a brilliant mod on your hands Twl. I was wandering if you guys have experimented with different material for the weights? I googled "bullet weights" and noticed that you can get them in many different materials such as led, brass, steel, tungsten etc. Initially I though that tungsten would be preferreble, as you don't have to handle the not so health frinedly led, but the tungsten weights are about half the size of the led weights because of the increased density. Now I'm thinking that this might affect the mod, as the weights would be shorter and not stick out as far. Any comments on this would be greatly appreciated. I recommend you try and search for "bullet weights" and "worm weights" on the Bass Pro website (http://www.basspro.com), that will give you a lot of options. You can even get some in funky red colors :) Thank you in advance. Anders |
Twl, I would be interested in knowing your thoughts on the groove tracer type design counterweight which appears to be a more mechanical amplification of the tecnoweight. Is it more beneficial for a low compliance suspension? Is it logical that the farther back from the bearing axis the side dampening effect is multiplied? Mmm....... Where might farther semi ridgid outboard weighting have diminishing returns.....is there a sweet spot or compliance ratio perhaps related to balanced off axis weighting related to dialing in suspension tuning? .... also any other currently avalible rega style counter weights that might be worth considering. Thanks in advance Jon |
Well, I bought a modified RB250 from a member who asked if I tried the TWL hifi mod. I said no but read the whole 23 pages printed out on this thread... I went & got some Blu tack (its called Fun Tack in Canada & sold by Lepage). But I could not find the bullet weights. Today, looking at some tiny metal cones I bought many years ago, I simply got out the tack and stuck a metal cone (about 1/2 onz weight) on each side.They are actually about 1/2 in dameter and again 1/2 high before developping a cone at the end. The difference is night and day! So much more information, so much more dynamics, detail and soundstage. But the sound!! Before I tought the sound was a bit flat and confined to the speakers. After this modification the instruments came really alive and I can hear so much more detail. Even my son comming down the stairs noted that the music really sounded wonderfull. All this comming off a Grado cart with a signature 10 needle. Would you beleive I get this from a Technics SL 1210 turntable with an acrylic platter and Maplewood brass heavy feet! I suggets you run , not walk to the store & get the $5 stuff - you will never take it off! Never mind reasoning it out or fear the bearing cant take the 1/2 onz load. I suggets you just try it.... Many years ago, people questionned big speaker wires; they reasoned this and that with very scientific measurements. They also questionned pointed feet for audio and speaker; they reasoned that one also... Just try it - you will never reason this mod again... |
since this issues has popped up again i will take the opportunity of saying "thanks" for coming up with this tweak. I used the bullets on the side of my rb250[eom1] arm and all the usual descriptors in realtion to this tweak applies. better dynamics, and more definition overall. Pictures are posted here: 1. http://gallery.AudioAsylum.com/cgi/gi.mpl?u=33809&f=twl2.jpg 2. http://gallery.AudioAsylum.com/cgi/gi.mpl?u=33809&f=twl3.jpg |
Hi Twl, Gilbodavid pointed me to this thread after reading my post on the "lenco thread". I'm glad he did, because I was unaware of it and I'm very much interested, but, reading through it, I realised that, maybe, it's not suitable in my case as I have an ortofon 530 MM cartridge which has a compliance of 25(?), and as you point, it probably isn't enough to move the arm. What do you think? It would look cool, though... |
Hi Twl, and thanks for your reply. I'm still frankly astonished. Thankyou again. I posted a new thread of suitible superlatives in your name because i think you deserve it for this, but the moderators seem to have disallowed it. hence the new post on this thread. Congratulations again for your "mod" which i actually think is more a wonderful inovation in the field of tonearm design, even if others have tried to impliment such ideas independantly at other times. I am amazed when something like this isnt taken up by huge numbers of audiogonners, magazines and manufacturers. It is no joke to say that it has raised my Rb300 to my OLSIlver level, and even surpassed it slightly, probably helped by the 4 feet cardas rewire that obviated any joins to other wire before the phono stage. I shall rave on for a while about this one! |
Have not read through every thread here...but... I used to own a unipivot Lurne arm from France that had this arrangement built into a hollow tube that was fitted perpindicular to the arm tube toward the rear. The tube contained two weights that you would push through and position to stabilize the arm just like a tight rope walker...worked great. |
just put this on the lenco thread. Thankyou Twl. simply astonishing... : Ok guys, here's the result on the RB300. IT WORKED! FIRST TIME! Ye gads. Dodgy phonos and no earth from the tonearm, and it does quite nicely. Now, with Michell Arm weight mod and my faithful Denon dl103r going through cardas cartridge pins into 4 feet of cardas tonearm wire, straight into the stepup, without the wire having run in for more than 1 hr it sounded ok, not brilliant, but ok. Bare in mind i'd just removed an OL Silver with all its superior price etc, that I'd been playing nonstop for a year plus. What i could now hear were vibrations (sibilence I think is the word) in the arm. Bass notes were muddied , imaging was lost, sparkle and prat werent there - Basically an inferior vibrating arm. Oh well, I need the money. Then lightening struck! I know, thinks I - I've got some of those fishing weights and bluetack that TWL was going on about, namely his hi fi mod!. Why not wack em on and see what happens. 2, yes 2 minutes later i had pressed the weights on with a liberal splodge of the blue tack, wacked a record on, and.... Bloody hell, i've got my OL SIlver back!!! This is not insignificant. This is not minor, this is £400 better and some. You know I think it might even be better than the OL Silver! What a laugh. All you RB300/RB250 people out there, hear me well. This is F.....g A! TWL should be knighted, rolled in clover, miss USofA'd to his heart's content and some. I'm in the next room typing this and it sounds better! Clearer, more focussed, more in the room.. just gone in for another listen, and wow it s cookin'. Lenco slam in spades. I'm a happy bunny. I've got a feeling we're heading towards OL Encounter land, as TWL himself said. Good thing I didnt try this on the OLSilver, I'd be weeping right now. Is anyone hearing what i'm saying... And the cardas cable still has to burn in. Hee Hee. |
Stephano directed me to this thread. I'm glad he did :) I have a DL103D on a modified RB300 arm (expressimo back end, no VTF spring, Cardas wire, no plug in arm pillar base, VPI VTA adjuster, planed underside of headshell and end of arm tube). For years, my general approach to upgrading and tweaking has been to identify each individual weakness and fix it. As a result, my tonearm has been setup to reduce the presence region resonance/shrillness in this arm/cart combination. I've applied several suggestions from Thorsten (decoupling cart from headshell, lead tape around armtube at 1/3 length) and set VTF and VTA to reduce the shrillness. After reading a bit of this entire thread, I got a 3/4 ounce "lead substitute" weight, cut it in half, drilled the ends, loaded them with modeling clay (temporary glue) and stuck 'em on the axle nuts. There was an astonishing change as all previous customers have reported. - large increase in bass resolution and extension - soundstage is more solid, bigger, paradoxically with less well defined instruments - shrillness mostly gone (yea!) Then I noticed that the top octave or two were gone. So I decided to set up the parameters that are tuned by ear -- VTA, VTF, and anti-skating -- again. Azimuth, overhang and offset are set correctly. Instead of setting these by ear to reduce the shrillness while maintaining a decent tonal balance, I followed a method that's new to me. Basically, you set VTA to get best focus on a mono vocal record, then set VTF to get best dynamics and realistic tone, then set anti-skating to get equal dynamics in both channels. See this post by Bernhard Kistner at http://www.audioasylum.com/audio/vinyl/messages/45126.html. First, I got some 1 oz. lead weights and redid the outriggers. Then set the arm up twice. After the first go round, there was an upper bass/lower midrange boost. This was due to the lead band around the arm. So I removed it and started over. As things have turned out, there is now almost no distortion and the tonal balance is pretty much as it should be with only minor HF rolloff. Many many records that were really "zippy" and sibilant are very clean and natural now. Most bass is much tighter. Unfortunately, some old bass-shy Mercs are even more so, though the definition is stupendous. I'd like to throw my hat into the amateur physicist ring and open up an issue. Several people have noticed the change in soundstage similar to what I described. I believe that non-identical moments in the lateral and vertical planes are the culprit, causing crosstalk between the channels that has an unknown phase relationship to the signal in the originating channel. If the cartridge body was perfectly stationary, azimuth perfectly set, and the groove was carrying a signal in once channel only, then the stylus would be moving in a plane at 45 degrees to the record, perfectly aligned with the generator for that channel. Now, if the cartridge is allowed to move in the vertical plane, then the stylus motion, relative to the cart, would be in a plane that is no longer aligned to the generator. This motion, as a vector, has a small error component in the plane of the other channel's generator. Depending on the actual motion of the cartridge in the vertical plane, this error component may be in phase with the dominant signal, out of phase, partly delayed, and this relationship may vary with frequency, arm resonant behavior, the behavior of the as an oscillating system over time, etc. Fixing the arm in the lateral plane by raising the lateral moment, while the vertical moment stays relatively low to allow the arm to track warps, is equivalent to the situation I just described. Thank you TWL for the mod. - Eric, three years too late to this party |
Finally it plays! My TT, born as a string driven unit, build on a rectangular shaped plywood with cadberg and scheu pieces, now is a nice drop-shaped, multi sandwich, lead filled unit. It's suspended on air (inner tube). The motor unit drives the platter "crossing" a flywheel. The arm, now rewired, sounds much more precise and free of resonances. All in all, I'm very satisfied. LP sound quite good. I've only a residual hum (apparently not related to arm grounding, but I still have to investigate). Another 250 is sitting, waiting for a hanging cw test... Ciao, Stefano |
Thank you Tom, I think (at least hope ;-) ) I'm aware of it. The overall resonance frequency of my actual setup would benefit from such a reduction. Should I need more mass, e.g. by changing cartridge, I thought I could add it nearer the pivot (or, e.g. by adding a damping foam inside the arm). Any recipe for DIY bead-blasting? |
Just be aware that when you are removing mass from the tonearm, you are affecting more than just vertical mass. There can be many consequences from doing this, that may or may not be what you want, unless you know what you are doing. Experimenting is fun, but can be expensive if you make mistakes. Regarding your question about sanding "hardening" the tonearm like bead blasting, the answer is no. Sanding does not work-harden the aluminum like bead blasting. |
Hi all, following Jeff Spall masterwork at www.william-reed.net/rega, I'm trying to apply some ideas to my RB 250 arm, and just wanted to share with your experience/thoughts: I already equipped my Rega 250 with an Expressimo endstub and counterweight and experienced a totally different sound from it. A good idea seems to have cw weight at a level which is as near as possibile at platter level. Now, while rewiring the arm with a cheap ultrathin wire I got (BTW it seems quite difficult to remove the enamel out of it), I thought of taking some more mass off the arm. The principle behind this would be to concentrate mass arm near the pivot, so reducing vertical inertia of the arm. So, last weekend, I cut out the lifter (most uncomfortable, but I decided to accept the drawback). Now, while Jeff pattern is spiral, Michell Technoarm has an array of 2 x 11 holes, all located in the inferior arm hemi-part. Thinking of mass distribuction, where the reduction of mass would give more benefits??? Thanks for sharing, Ciao, Stefano P.S.: Would be sensible taking the paint off with a sanding approach (a la Dremel) be a way to achieve a sort of hardening of Alu (similar to bead blasting)? |
It would have to do with resonance modes and reflections in the tonearm system, regarding the interconnected masses, and their positions, and the method of their contact with each other. I didn't do any measurements with my hanging counterweight. I just "theorized" that it might be good to get all the mass down at the level of the record(and remove the mass from being bolted to the armtube), and tried it. It was a little better than the Heavyweight. Sometimes you just have to go with your "gut feeling" and try things. |
Umm...mebbe, but I dunno. I think this one resides in the thought experiment file (along with most of my others :-) For one thing, it violates the KISS principle. For another, a string attached to the tonearm and pulled taut will have a very defined resonance, like a guitar string. But mostly, I just can't fathom why doing this would be beneficial. As opposed to your HiFi concept, which stemmed from an actual theory of its positive effect. I'd just be mucking around in the dark with no clear idea of why. This only occurred to me in response to your post about hanging counterweights, but taken to the max. If I have an opinion on this at all, it's that a conventional counterweight would probably be just as good or better in the real world. But if someone can explain to me why 'decoupling' the counterweight is ever attempted in the first place, maybe I'll change my mind and decide I could be on to something... |
Alex, that sounds like a workable idea. Maybe you should try a mock-up of it and see how it sounds. That's all I did. I had an idea, and tried it out to see if it worked to produce better sound for me. I'm sure that there are plenty of other improvements to be discovered, that none of us has thought of yet. The stuff that I made is just another "stepping-stone" towards improved sound and improved design ideas in tonearms. There will be others who are spurred on to make further improvements on top of what I have done, or entirely different directions. I'm just glad to have been able to contribute something back to the hobby. Regarding your particular design idea above, I think it is interesting to use a counterweight "lift" in front of the bearing, instead of a "see-saw" behind the bearing. This may have some interesting resonance effects, and possibly with careful implementation, could result in some resonance-reducing effects in the armtube. This would require experimentation. I think it would be worthy of trying out to see just what you can get out of it. After all, tonearms aren't the most complex items in the world, and most of us could actually build a whole tonearm that sounds quite good, if we set our minds to it. I enjoy seeing some other insights into the tonearm design issue, and love to see the seeds of innovations being brought to life. Go for it. |
OK Tom, without going into every detail to the Nth degree, here's what's on my mind now: First of all, I'm not sure I fully understand why or if it's necessarily desirable to decouple the counterweight. Or to go for lowest mass in general. But if we assume that these are desirable goals, then why not get completely rid of the coupled mass of the counterweight? Hanging the weight off the end of the tonearm's rear extension seems like it would invite a swinging motion in response to energy inputs at the stylus, since the string can't perfectly decouple the weight. Additionally, the weight would be free to oscillate in response to spurious energy inputs to the plith as a whole, such as from loud bass notes or footfalls. Today's post is a simpler design then in the post I deleted. End the tonearm at the pivot point, with no extension continuing behind it. Take a cue from the design of a conventional suspended-weight anti-skating arrangement. Hang a weight from a string, run it over a hanger positioned above the tonearm, and attach the string to the tonearm (moveable to fine-adjust VTF). The force of gravity pulling down on the weight now pulls up on the tonearm, offsetting the force of gravity pulling down on the tonearm/cartridge, minus the desired tracking force. The hanger is mounted on the horizontal bearing housing, in order that there will be no lateral relative motion between the hanger and the tonearm. The hanger (and therefore the weight as well) must rotate along with the tonearm in the lateral plane so that it ignores the lateral component of the tonearm's movements. With the directly-hung counterweight described above, motions of the tonearm in both planes affect the motion of the counterweight. The counterweight 'sees' all the vectors and reacts accordingly. But with an intermediate hanger to run the string over, like is used for anti-skate, motions of the tonearm in both planes have only their vertical component transmitted to the counterweight. The counterweight 'sees' only vertical inputs, and accordingly moves strictly up and down, rather than like a pendulum. But the counterweight might still move in response to spurious inputs. So, give it a streamlined shape and immerse it a dampening fluid bath. The trough, like the hanger and the weight, will have to ride on the horizontal bearing housing. But this might not be a bad thing, since we removed the mass of the tonearm's rear extension and attached counterweight, and we might want to bump up the tonearm's lateral mass in isolation, like you do with the HiFi mod. Anyway, if decoupling the counterweight is what we want, then I can't think of many ways to decouple it further than this. I'm just not sure it would accomplish anything... |
I've used the C/W Twl just described on my O/L Silver, based on his description earlier on this thead. I can confirm all the sonic changes and benefits he described. One more tip: adjust the mass of the weight so you can hang the thing as close to the pivot as practical for proper cartridge balancing and VTF. This should improve warp tracking and reduce the weight's tendency to swing. I would not necessarily want to use a free hanging C/W on a floaty, suspended TT. On a solid, nonsuspended one it's a nice upgrade. Not as big as the HIFI Mod, like Twl said, but it really does reduce armtube resonance reflections. This results in less overhang on virtually all notes, for a cleaner and tighter presentation. Recommended if you can deal with a bit of fiddliness. The O-ring is essential, the C/W would be insufferable without it. |
Stefano, I don't have any photos. But I can explain. First, we must look at the way that I have the hanging counterweight slung under the tonearm. I use a length of Spectra fishing line, which is high-tensile non-stretch line. Then I hang the long shaft-shaped counterweight on 2 points(each end of the weight) and sling the line over the tonearm. This gives the mass effect in the lateral plane as well as horizontal. Then we must look at what we are trying to accomplish. First, it is understood that the counterweight mass should be as near the plane of the record as possible, for best tracking ability. The standard Rega counterweight does nothing in this regard, as the mass is all centered at the same plane as the tonearm. The Expressimo Heavyweight does lower the plane of the mass(by making the hole off-set) and has more of the mass below the tonearm, for better tracking. But the off-set hole causes the tonearm to shift tracking force when the arm rides up over a warp, because the mass distribution is unequal in the vertical plane, and when the arm rides up over a warp, the bulk of the mass of the Heavyweight actually moves foward around its rotational circle(which is different than the rotational circle of the tonearm). Additionally, the mass that is below the tonearm on the heavyweight only comprises a relatively small shift in the center of gravity of the counterweight mass(although it is audible improvement). It has a price, and that is the counterweight mass is no longer symmetrical when the arm is in vertical motion. This is the reason why Mark Baker is not using an off-set counterweight on his OL tonearms. Now, to make the full step to making ALL the mass of the counterweight at the same plane as the record, for best results, requires some different implementations. First, the mass must be equally distributed in all planes for symmetrical operation during movement of the tonearm during play. Second, it must provide the normal counterweight functions, which are balancing the arm, providing tracking force, and providing a certain amount of lateral stabilization. By hanging a shaft-shaped counterweight cross-wise under the arm end-stub, we can hang it like a child's playground swing, with the string slung over the end stub. By slinging the string over the end-stub, we have lateral stabilization as well as vertical, because the string wraps over the end-stub and has enough contact around the diameter to provide the mass effect laterally on the tonearm. The non-stretch string(Spectra fishing line) provides a solid tie to the counterweight on each end, thus effectively making the counterweight operate as a solid tie to the tonearm in the lateral and horizontal planes. However, the counterweight will still "yaw" in the "z plane"(fore and aft), so that the counterweight mass will remain plumb under the end-stub of the tonearm during rise and fall during warp play, and still retain the correct tracking force, and still maintain the correct position of center of gravity down near the plane of the record. The result is that ALL the mass of the counterweight is now moved to the correct position at the same level as the record, not just some of it. Also, the mass remains efffectively constant during vertical movement of the arm. Third, and possibly most important, the mass is effectively mechanically decoupled from the end-stub, which results in a free-er sound, less encumbered by high mass and addtional parts, so its natural resonant properties may occur with less reflection and harmonic effects due to 2 different masses being coupled together by a screw at a random point on the end-stub. The string has a natural resonance damping effect by simply vibrating, and the ends of the string are placed into the lead mass of the counterweight shaft, which has sufficient mass to absorb and damp the vibrations. Regarding your question about horizontal stabilization effects, the hanging counterweight is coupled horizontally well enough to provide this stabilization function. Remember, that the purpose of horizontal stabilization in the tonearm is to prevent it from being moved by the compliance of the cartridge during play. If it gets into motion from these forces, we have already failed to stabilize it. It is the "static moment of inertia" which we are dealing with here. The amount of force needed to start this body into motion. If the static moment is higher than the cartridge(on the arm) can apply, then the arm will be stable, and not be moved into unwanted motion by the forces applied by the cartridge, and the performance will increase, because all the stylus movements will then be generated into electrical signal, and not lost in unwanted arm movement. I wish to mention however, that this is a small increase in performance, not on the level of the HiFi mod. It will add to the sonic performance of the arm in an amount of a few percent. The liquidity is better, and the sound is more open. I have found that just slinging the string over the arm, results in a "crawling" effect of the string on the end-stub. This causes change in tracking force, and is unacceptable. I then put a rubber O-ring on the end stub, to act as a "stop" for the string, so that the string cannot crawl toward the back of the end-stub, which is where it wants to go. It is not needed to put an O-ring in front of the string, because the string only wants to crawl backward. It also acts as a guide for replacement of the counterweight, if you ever want to remove it for cleaning or anything. You just put the string back on the end-stub, just contacting the front of the O-ring, and you have your pre-set tracking force established. Setting the tracking force with the O-ring is place the first time, is a bit finicky, and can be tedious. But once it is placed, the position is set, until you move the O-ring. If you want to make small VTF adjustments, it is advisable to use Doug's VTF on the fly modification, since small VTF changes with the O-ring is a pain in the ass. |