Zaikesman,
I remember posting somewhere (maybe on this thread but who could find it) that side weights threaded for in/out adjustability would be useful. I think the tungsten side weights on the Graham 2.2 are like that (4yanx?).
My thought was just an instinct, not as well thought out as what you and Tom are doing. I really appreciate the continuing contributions to tonearm theory engendered by this thread. Maybe I'll uprade my HIFI Mod some day, though I can't imagine how I'd get the existing weights off without wrecking the arm.
To heck with this pivoting nonsense. I want a Kuzma Air Line! I'm off to buy a lotto ticket... |
Double Bubble. It reinforces the effect of the divergent resonance points... :-)
Tom, your technical analysis of what might constitute the optimum range of added lateral mass and why is a good deal more sophisticated than I could manage (not that I can't follow the gist of it, i.e., what matters are the forces in play at the stylus tip with mechanical multipliers taken into account, not the raw masses involved - I think). So I will just second it with an alternative observation: the existing counterweight on any conventional tonearm is at least as massive as your 24g of added weights, and I would guess probably more often 2 to 4 times that amount, whereas the cartridge, out at the end of the tonearm lever, is roughly 1/2 to 1/4 as massive (as the added weights). At set-up, the counterweight is first balanced against gravity with the cartridge installed, then moved inward toward the pivot to effect the desired vertical tracking force. This action could be seen as 'unbalancing' the cartridge in the lateral plane by the same amount as the applied VTF - and Tom's added weights could be seen as a method of 'restoring' static lateral balance by providing a 'counter-counterweight' that operates only in the lateral plane.
Of course that's not a literally true analogy, because gravity is operating only in the vertical plane, but the lateral accelerations applied by the spinning record at the stylus tip are real, and they can be presumed to be basically equivalent to the vertical accelerations (caused by same) that gravity is enlisted to help manage in the vertical plane. Now, because the groove wall is cut in a 45-degree "V" angle, the downward VTF applies the same restorative force in the lateral plane as in the vertical when the stylus is deflected side-to-side. There is a difference however: in practice, the cantilever is always deflected vertically upward by the VTF, even at rest, whereas laterally it always returns to center. Given that scenario, plus the fact that warps which need to be tracked by the tonearm are mostly a vertical phenomenon, there would seem to be elbow room so to speak for increasing what we might call the 'lateral dynamic tracking force' against which groove accelerations act in the lateral plane. In other words, we can think of Tom's approach (of increasing lateral mass) as effecting a sort of separate, and higher, "VTF" for the lateral plane.
These musings inspire a vision of what Basement refers to as a 'properly designed' (pivoted) tonearm: maybe such a creature would have not just a rear counterweight, adjustable forward and backward to effect proper tracking force, but also side counterweights concentric with the pivot point mounted on extensions of the fixed axle, adjustable in and out from the pivot in order to effect optimal lateral counteractance to forces applied at the stylus - while the whole shebang would be fluid-damped. (And: might such adjustable side-weights even be able to effect some form of dynamic anti-skating compensation?) This seems to me the logical extrapolation of Tom's mod... |
Doug, thanks for clearing that up. I couldn't remember exactly what you stated in your post, and I just made a mistake in writing that you had a 501.
BTW, I have always thought that Bazooka was the best bubble gum! :^) |
"Doug Deacon's HFNRR test record measurements with the Hifi mod installed on his OL Silver yielded a near perfect 11Hz vertical, and slightly higher horizontal with a Shelter 501 Mk II on his arm (if I remember his post correctly) Both were well below normal audio range, and above rumble frequencies."
From memory:
OL Silver
HIFI Mod
Tom's suspended counterweight (described above, I think)
Shelter 901
~ 9Hz horizontal
~ 11-12Hz vertical
The suspended C/W is not quite as heavy or as close to the pivot as Tom intended. OTOH, reducing the vertical moving mass would raise the vertical resonance frequency still higher, right?
If Alex's new thoughts are correct, then it's okay or even desirable to have the lateral resonance freq lower, and reducing it even more might have a good effect. I'll have to add some bubble gum to the weights, remeasure and do some listening. Any suggestions for the best flavor? ;-)
Doug |
Good points, Alex. In fact, some tonearms do have added mass in the horizontal plane, provided by the bearing housing structure. Others have a large bearing housing, but the bearings that control horizontal movement are only holding a low-mass ring which is part of the gimbal system, so those don't really help in that regard.
In early tests of the other OL arms like the Encounter and the Illustrious, I found that the horizontal mass(large bearing housing) in those arms was already sufficient to preclude the use of the HiFi mod. And in fact, they sounded better than my OL Silver with the HiFi mod. This shows that horizontal mass is important, but is only one aspect of the design, and other things still are very important.
Your comments about the amount of mass increase being similar to VTF force is very astute. However, the mass increase that I use is about 12g per side, or a total of 24g. This is placed at the pivot, which is not augmented by the F x D^2 multiplier of the long arm tube that multiplies the effect of stylus accelerations at the pivot. In order to counteract forces and accelerations that are multiplied by the leverage of the long armtube(9"), a larger mass is needed at the pivot, than the typical cantilever and suspension may be exerting at the headshell. Even this 24g increase seems insufficient. My testing has shown that even though the increased mass may seem insufficient to counter the forces and accellerations that the cartridge produces, it is the increase in Coulomb's Friction(static inertia) which is the key to this HiFi mod's performance. This increase in Coulomb's Friction causes the static moment of inertia of the tonearm system to be higher than the stylus deflections can overcome on a short rapid momentary acceleration during play. This is why the cartridge performance is increased, but the slower movements of spiral tracking of the groove are relatively unaffected. Higher amounts of mass increase could be counterproductive to normal arm movement across the record. I know we had this discussion about static moment of inertia earlier in this thread, but I neglected to mention Coulomb's Friction at that time. It is different than the typical dynamic friction that we are all familiar with.
Doug Deacon's HFNRR test record measurements with the Hifi mod installed on his OL Silver yielded a near perfect 11Hz vertical, and slightly higher horizontal with a Shelter 501 Mk II on his arm (if I remember his post correctly) Both were well below normal audio range, and above rumble frequencies.
Regarding your interest in higher frequency performance of the damping trough, it is interesting to note that studies have been done on arms with removeable headshells, and it was found that 1kHz was a typical resonance peak resulting from the joint of arm/headshell. If the damping trough works well at that frequency, it may well prove very effective on that resonance, as well as others.
A damping trough working in conjunction with increased horizontal mass is an intriguing idea which could merit some experimentation. I have not tried that combo personally. It sounds like a good idea.
Thanks for your input. |
I want to go just a bit further and break down just why I feel Tom's idea constitutes a intriguing and enlightening approach. In the past, before coming to some understanding (with the help of the contributors to this thread) of what the HiFi mod represents, I had - I'll assume like most of you - regarded effective mass as a monolithic quantity. Tom's insight made me aware that we should properly take into account two separate quantities of mass, vertical and lateral.
The reports above of those who've tried his mod testifies to the validity of his fundamental underlying proposition: that information retrival may benefit if these two quantities are not treated as being always interchangable - that in fact, performance may be improved if these two quantities are made slightly divergent. Two divergent effective masses instead of one also implies there being two divergent points of resonance (cartridge compliance still assumed to be constant in all directions). I wonder if this presumably 'double-humped' resonance distribution might itself be partly to credit for perceived performance gains, as a result of the altering of the system's "Q" characteristic to be less intensly concentrated at one specific frequency ; in other words, maybe simply making the lateral and vertical mass - and therefore resonance - components somewhat different from each other could be as significant a reason for improvement as the action of additional lateral mass itself.
This an untested hypothetical of course, but we do know that there is a several-Hertz range within which 'proper' system resonance may ideally fall, usually given as from 8 to 12 cycles per second. This value range is considered low enough not to be excited by music, but high enough not to be unduly excited by record warps, big dogs, passing 18-wheelers, distant earthquakes, etc. So there is obviously 'wiggle room' to for instance make the vertical-mass/cartridge-compliance resonance point = 10Hz while the (higher) horizontal-mass/(constant) cartridge-compliance resonance point may be brought closer to say 5Hz without having to worry about extraneous inputs of (primarily vertical) infrasonic energy ruining your tracking day.
The viscous fluid approach , while not imparting inertial effects (and in fact counteracting them), does little to damp such low frequencies, and won't really alter the distribution of the system resonance. (I want to stress here, in relation to this inertia business, that Tom's added weights do not encumber the cartridge suspension in a discriminatory manner that is out of the ordinary ; the suspension must deal with the tonearm's mass inertia anyway, whatever its value. Gravity helps maintain groove contact in the vertical dimension through the VTF setting ; laterally - particularly with really good bearings - it seems to me that inertial mass ought to be able to stand an increase at least roughly equivalent to the VTF.) I observed near the top that fluid damping ought to be superior to the HiFi implementation in terms of HF damping, and this analysis suggests that maybe the two concepts are actually complimentary.
Funnily enough, after so long since this thread began (and after having previously inspected my own tonearm to see if it could be made to accept something like Tom's mod, which I concluded it really couldn't due to its physical design), this late conversation spurred me to go downstairs and look once again - this time with a new notion in mind. And hot damn, there it was: the 1200 tonearm already incorporates added mass in the lateral plane! I'd been looking at it the whole time (the brain sure can work slowly... :-) I think a lot of gimbal tonearms have been made like this: it has a 'carriage' containing the vertical-plane bearings which itself rotates in the horizontal plane (it's mounted within the 'tower' assembly holding the horizontal-plane bearings, which is itself stationary). This 'carriage' structure is basically a rectangle, open in the middle (the arm passes through it), made of cast alloy about 1 1/2" wide by 3/4" tall by 1/4" thick, which incorporates the steel vertical bearings ; when the tonearm moves vertically it remains put, but it rotates in the horizontal plane right along with the tonearm when it is moved laterally. I would estimate its total mass as being roughly in the ballpark of Tom's fishing weights. D'oh! |
I think it is worth pointing out that what a properly designed tonearm IS, is the result of continuing to try to improve the design, that is, further the knowledge and design of the technology. That is why it is so much fun that twl shares his improvements with us. Any tonearm can be improved. If it interest you, go back toward the beginning of this long thread and you will see what fun we all had in trying to determine the validity of Tom's modification. There is actually enough here to demonstrate that the modification is of proper design. This is a LONG and old thread. The mod (lateral mass) is proven in listening test, compatability, the theory behind the mod is also put to the test, and it is shown to be an improvement not only to the overall sound, but is a more properly designed arm with it.
If you are truly interested in what a properly designed tonarm is, and want to have real fun, notice how many highly regarded and well designed tonearms DO NOT take note of the the aspects of TWL's design, and if you execute it properly, many arms could be improved the same way. (notice that some arms have uprades that go in this direction). The rb-series of tonearms have some really good aspects to them, namely the design of the armtube and the bearings, as well as some aspects that are overlooked.
The mod works so well that the performance of the arm comes scary close to some VERY good arms, and evan surpasses a lot of very good arms in certain, important areas. It is amazing what you can achieve with a little knowledge of tonearm design. |
Thank you Alex, for your succinct description of the pros and cons of the mod, and the importance of matching the application. |
Tom brings us back to the point about cartridge compliance and the efficacy of doing a mod like his. I have been thinking about this recently since I installed a van den Hul DDT-II Special in place of my previous Benz-Micro Glider M2.
The vdH's have higher compliances than is usual for most MC carts (and their upper-line models even more so than mine), yet the DDT does not seem to suffer from being run with the same viscous fluid damper settings I used with the Glider. But I'm not sure this would be the case if I had Tom's mod instead of the KAB damper, due to the point I made somewhere above about the added mass imparting not only increased resistance to lateral deflection of the tonearm (as does the viscous fluid), but also continuing intertia once put in motion (which damping fluid does not have).
This sheds some light on a problem that baffled me near the top, namely why Tom felt the mod increased susceptibility to skipping on scratches: it's the intertia - I just didn't put the two together before. There's probably a 'threshold' effect at work: light scratches may actually be less prone to cause skipping with the added weights installed, but these kind of scratches might not normally cause skipping anyway - while scratches beyond a certain magnitude (that acutally cause the stylus to break contact with the groove) may cause a lateral arm deflection that is less easily brought back under control once begun due to the added mass inertia.
Anyway, we see that increased lateral mass mandates matching to a relatively low-compliance cart, such as Tom's Shelter. This is of course no different a concept than the standard one about matching compliance to overall effective arm/cart mass, with the exception that Tom's use of increased *lateral* mass *only* means that there will be little or no effect on system resonance excitability due to infrasonic warps, footfalls and the like, or LF mechanical feedback (which tend to be primarily vertical in nature), nor due to the low bass content of lateral-cut (mono) or diagonal-cut (stereo) recorded music (since the added mass only lowers the resonance point, presumably already below the 20 Hz maximum). So bass performance is enhanced, tracking is maintained, and skipping susceptibility is worsened (but not if your records don't have scratches).
Still, you could say about viscous fluid damping that the bass performance should be likewise increased, tracking may even be slightly improved (fluid does provide a bit of extra vertical damping, though not as much as laterally, due intentionally to the shape of the paddle), and susceptibility to skipping is ameliorated (or at least reduced in magnitude when it occurs). At least one could think so. In my own listening tests with the fluid damper, I mostly heard a cleaning-up of the soundstage, a purer, more extended treble response, and bass that sounded more natural in timbre but not necessarily more extended or dynamic (those tests done with the Glider). I can state that the damper doesn't worsen skipping, but haven't done the tests to state that it really improves this aspect either. In any case, fluid damping does seem to permit the use of carts in any compliance range (indeed, the KAB product, dedicated as it is to the Technics SL-1200 table/arm, will likely be most often used with high-compliance MM carts featuring relatively high-mass tips and cantilevers, such as the models made for club DJ's and hiphop turntablists).
But since KAB evinces no interest in coming out with a fluid damper for Rega-sourced arms (despite my opinion on the market potential there), Tom's mod would seem to be it for owners of such arms - provided (as he states) that they are running a cartridge of suitable compliance. Looked at that way, what he essentially did was come up with a clever method to improve the match of his tonearm to his choice of cartridge, without paying a penalty in reduced trackability. |
Rauliruegas, yes I agree that if the tonearm is properly designed, that there will be no need for my tonearm mod. Unfortunately, it seems that many are not properly designed. So, improving the lateral mass is appropriate in many cases, but not all. Also, it depends greatly upon whether the cartridge is low, medium, or high compliance, as to whether additional lateral mass is even needed. In any case, this mod is strictly for OL Silver and Rega tonearms, and it has been demonstrated that they perform better, with many cartridges, by having additional lateral mass placed in the proper location.
I have never presented this modification as a "panacea" for all arms and all cartridges, but strictly for Rega and OL Silver arms with lower and medium compliance cartridges. Other arms may also benefit, but that would have to be determined on a case-by-case basis.
Thanks for your comments. |
Dear friend: I have around 18 tonearms. You have a point that maybe it's valid, but when a tonearm manufacturer has a good design and a good execution ( it does not matter wich kind of tonearm bearing design ) you don't have to worried about it. If with this " mod " you have a different sound maybe is because your tonearm is not first rate.
By the way, you say that a heavy tonearm is a bad traking arm ( vertical ), well this is not in that way. All depends on the cartridge/tonearm match and in the tonearm bearing.
Cheers.
raul. |
Hi Damian, while the unequal weights may possibly effect a change in anti-skating, it is not recommended to do that. It has other effects too, which might include affecting the azimuth, causing unequal bearing loading, among other things. If you need to adjust your anti-skate, I'd recommend approaching it from a direction that influences only anti-skate. |
Let me ask youguys a question. I've printed out the thread and I'm still reading thru it so I hope it's not been answered before.
I'm using a very crude version of this tweak on my backup 'table, a Sony with no antiskating (the arm is a POS). It seems to have cleared things up a bit.
My take on the tweak was a thin metal spatula (what I had at hand) for which I found what I thought was the mid-point, affixed with a couple tiny drops of glue to the top of the tonearm casing. I looked at it with a flashlight from all angles and it appears to be straight.
I later made 5-coin stacks, held together with drops of glue, and added one to each side of the rod, just for the heck of it. I can't say I'm noticing much further improvement.
Anyway, about antiskating. I noticed the rod isn't quite centered on the tonearm pillar (wonder just what I was doing when I marked the mid-point on it), but rather one of the sides is hanging out more than the other.
This end is on the 'outside'. Is this the 'right' side for the offset weight to counteract the skating force, or should I mount it the other wayround?
Thanks! |
Hi Janvoorn, I have read much of the writings of Poul Laadegard, and even made a prototype of his famous linear tracking tonarm once. He is an interesting fellow. Thanks for the tip to the website.
The Van Alstine mod was completely different, because it was positioned at the headshell, and affected both the vertical and horizontal mass. But, it may have helped with azimuth control on unipivots.
Actually, this HiFi mod only makes up for the lack of engineering on the part of most tonearm designers. It seems that the majority of cartridges made are wanting a bit more lateral mass in the tonearm system. |
Tw1,
for some reason or another I never discover this thread. Just to add something to the discussion I would like to mention the following: I opened a discussion at Vinyl Engine which concerns the theoretic background of effective weight in the lateral and vertical direction. Some links to texts written by the famous air arm inventor Poul Laadegaard heve been added. The thread is called:How important is arm resonance frequency? Can it improve sound quality? You can find it at page 4 of the Turntable Talk part of the forum overthere.
Perhaps you know of the existance of another theoretic paper on this subject? A site by Van Alstine on the web published a similar mod mounted on the cartridge, but I think that one is not good for tracking. the thread at Vinyl Engine leads us to a last open question: how does Mr Laadegaard himself think about the 1977 AES paper at the moment? Unfortunately he is very silent about this. He did not answer my email to the B&K- office in Denmark.
Jan |
Thank you for sharing this, I tried it and am utterly delighted and awestruck! I had been quite happy with my fully Expressimo-modded RB250, but noticed that cymbals were not pronounced enough for my pleasure, I had been tweaking with mats and thought I had it solved, but then it backed up and I was at square one. I had acquired some of these bullet weights to see about spikes for my gear, they didn't work, but then brought them out for this suggestion and am very impressed! |
A quick note. I've used the offset HI-FI tweak for months now, since last fall, and have not the slightest doubt that it is effective. Regarding being able to see the cantilever I can't force anyone to agree with this, of course, but I've got a Denon DL-103D cart (with tag reading 1978) that has a fairly easy-to-see cantilever, and my table is placed just in front of a window which, with shade open, allows brilliant natural light to flood in. Anyone - I repeat, anyone - who doesn't have a fairly serious vision problem would be able to see the movement of this cantilever as it varies according to setup. Thanks, folks. |
Yes, I should not have actually said, "shifts the forces", I should say shifts the relationship of the forces. It gives the various different forces a different relationship (equation) as they relate to each other.
You are correct- if we hang a tonearm straight down, and get gravity to pull it to one side, and put it on the table again, there is no longer any gravity pulling it sideways. It would not have force to pull it to one side. In actuality, the force of the cartridge on the pivot point does not change either (unless we increase the tracking force).
If we visualize a tonearm hanging straight down with a radically offset mass, you can see that it would take a certain amount of pressure to hold it to hang straight down. And the offset weight is resisting gravity. Replace the gravity in this visualation with the pull of the cartridge. It takes more effort to pull the cartridge one way than the other.
While radically shifting the weight in this manner will not actually pull the cartridge in a direction, it will alter the resistance to such a pull. This then also changes the effect of the pull on other forces. The cartridge will pull to one side more than the other, not because there is more pull in one direction, but because there is more resistance in the other.
This can lead to some pretty deep thoughts on anti-skate. While it is the offset angle of the cartridge is what pulls the arm to one side, the pull is actually directly in line with the cantilever. But, we do see that the cantilever deflecting to one side (when we can see it). To use offset mass as opposed to actually applying an offset counterforce, might be a more effective, and accurate way to deal with anti-skate. |
Hi Basement - Your explanation seems to make good sense for a moment, but then it occurs to me: In the case of the balanced lever on a pivot, gravity is working on its mass throughout its length and in equal proportion to the distribution of that mass, while in the case of the 'sideways' tonearm situation, the skating force (unlike gravity) is always being applied unequally only at the point which the stylus touches the spinning vinyl, no matter how the mass is distributed. Is this really analogous?
Shirasagi: You could make a more obvious demonstration by employing the smooth uncut track featured on some test records (older ones anyway) for adjusting anti-skate. The net effect of unequal side-weighting on skating - provided it is present - would be much more readily observable this way than by trying to eyeball the tough-to-see (and impossible to visually quantify with precision) stylus deflection differences. |
I'll jump in here for a sec. to add that I've used Twl's "HI-FI" tweak on a vintage Empire 598 table w/ 598 tonearm, employing a heavier and longer lateral weight on the "right" or outside of the arm yoke to generate anti-skate (the inside weight is quite small). It doesn't take much in the way of high-tech testing to verify the outcome of setting my arm up this way. All one has to do is closely eyeball the cantilever as it touches down on spinning vinyl: without the offset HI-FI tweak the arm "wants" to move "in" towards the platter spindle and the cantilever bends "outward" away from the spindle in response; with the tweak installed the cantilever remains straight upon touching spinning vinyl, and remains so. My vintage arm used an A/S spring tucked inside the yoke that created resonance issues, now gone entirely since I chucked the spring and discovered the A/S effect with help from Twl. A while back I engaged a lengthy argument on the Vinyl Asylum regarding such A/S effect and it turned ugly, personal and stupid; the gist of it was "me" saying "it actually works!" and "them" saying "but it's not physically/mathematically possible...so you're an idiot, etc." No more arguing for me - it flat works. It "has" to work, in the sense that the fact of the A/S effect only validates the basic concept of the *concentric* HI-FI tweak...beneficial effect of which has now been verified via user reportage again and again. Personally, I think it's just about the coolest thing I've learned since taking an interest in vinyl. BTW, I fiddled with the left-right balance (length and weight) of the offset HI-FI tweak by ear, the aim being to get a centered stereo image. |
Zaikesman, I believe I can explain this phenomena, and it is interesting because it relates to the effectiveness of this mod.
You are correct in your visualization in that in a pivoted arm, movement is restricted because of the fixed position of the bearings, and wieght placement will not alter what the bearings allow, but it can, and does, shift the forces on the bearings and the amount, and this affects the direction of the forces and the resistance to force.
picture a straight rod with a pivot in the center and equal wieghts on each end. if you bend the rod at the center so that one side is down and the other is level, the other side will then wnat to come down as well, evan though you haven't changed the weight on each side of the pivot. now picture the same straight rod with a lot of weight on one end. the location of the pivot has to change to make them balance.
now flip this stuff sideways and consider the pull of the cartridge on the pivot of a tonearm. to shift the mass in relation to the pivot will shift the force on the pivot, just as changing the location of the pivot change the balance of the arm. in the case of the lateral force, or the anti skate, it would shift to one side of the bearing.
if you were to remove the arm from the table and hold the arm so it hangs toward the floor, it would not hang straight down if you had more weight on one side than the other.
with the arm on the turntable, there is no force on the bearing until the record spins and pulls the stylas away from the pivot. with a change in wieght distribution, you change the amount of force required to pull the cartridge from one side to the other. the nature of the hifi mod is to increase the lateral mass as to increase the resistance to sideways movement. to add a weight on only one side will still increase resistance in both directions, but will increase it more in one direction than the other. |
Interesting. It does seem somewhat counterintuitive (in the case of a gimbal 'arm only). Obviously, the situation cannot be totally analogous to an anti-skate hanging weight arrangement, since in that case the connecting piece of line and bracket over which it hangs work together to apply the gravitational force in a lateral vector. Your experiments seem persuasive though, so it would be educational to find out the reason for the observed behavior. I would suppose that to someone with the requisite knowledge of basic dynamics and the fundamentals of the application at hand, this would be a "D'oh!" question, but judging by your own uncertainty, and the certainty of some of your (presumably well-versed) correspondents apparently being at odds with experimentation, perhaps not. As I mentioned above, I don't think that an S-shaped 'arm (such as my own 1200) would be statically balanced in its lateral mass distribution, and the argument could be made that uneven mass distributions as seemingly innocuous as headshell offset or a headshell finger-rest, operating at the distance from the pivot point which they are, should then be almost as disruptive even on a straight 'arm (or could those two factors cancel each other out?). As far as the TT leveling necessity goes, this is of course true anyway - extra weights or no - since the unbalanced (due to the applied VTF) mass of the 'arm/cart is always in play. |
Zaikesman, because if it is not, it will cause the tonearm to have a lateral force applied in the direction of the heavier weight, like an anti-skating adjustment. I have read arguments from others that this is impossible and physics dictate that it is impossible. I counter that argument by having done experiments that show it is not only possible, but predictable. I have done leveling and every other precaution, but it happens. One person who bought the mod got so anxious to listen that he tried to play with only one weight installed, and the tonearm skated all the way across the record from just a slight bump! So, no matter what some may say in theory, in practice this is an issue that must be dealt with. Perhaps it is simply because ideal theoretical conditions cannot be met in practice, in this application, and the bearings are smooth enough to allow the drift. Small variation of unequal weight may be dealt with by adjustment of the anti-skate mechanism on the tonearm. Whatever the reason, it is important to have a reasonably close match of the weights that are used for this purpose. I'm not saying that it is necessary to take this down to the 1/10000 of a gram, or anything. Just make them pretty close, and that should do it. When I make them, I just eyeball them for the same length, and use weights from the same package that were pre-weighed before I cut the depressions in the ends. That has been close enough for all my previous work. Also, it should be noted that the length is important, because the force applied increases by the square of the distance from the pivot. Since this is a geometrical increase, the length of the weight(which creates the distance of the center of mass of that weight from the pivot) is pretty important also. I made the weights about an inch long, because I am using that geometrical force increaser to assist the desired effect, while keeping the actual mass that I'm using to a minimum for the application required. |
TWL: I brought this up before in my post of 8/31/03 (gad, has it really been that long? Where does the time go?!), but I will ask again since you mention it now: Why exactly must the mass be equally distributed on both sides of the (virtual) pivot point with a gimbal 'arm? |
Johnnantais, I think you will like it. This mod is just like the types of things you like to do: cheap, easy, and effective. I like those kinds of mods too! I made the mods for my tonearm and a DL103 cartridge with 12gram weights on each side, for a total of 24gram increase in lateral mass. For cartridges with a more normal medium compliance, less mass is needed. With Grado or other high compliance cartridges(including Cartridge Man Music Maker II), it may not be needed at all, and could cause the "dreaded Grado Wobble" when playing.
NOTE: The mass MUST be equal on both sides of the pivot.
I figure that this mod on your Lenco/Rega setup should send you directly into audio Nirvana! I really do think you will be surprised at how much better it sounds after modding.
Have fun!!!!!!!! |
Alc777, the Graham weights have two functions. The primary reason for them is control of azimuth-rocking on warps. Stabilizing lateral inertia was a secondary benefit AFAIK. On a gimballed Rega or OL Silver no azimuth control is needed, so the primary (only) effect of Twl's weights is the increase in lateral effective mass. |
Twl, I must say that I will have to try it as well, as I'm a sucker for DIY mods. Good lateral thinking! |
Is this the same thing that Graham used in his arms for azimuth balancing? |
Bombaywalla, glad you finally got a chance to try them. We demoed our OL Silver both with and without the weights before glueing them on permanently. It was no contest.
You probably did the right thing using a little less weight for the Benz. Twl will have to come out with HIFI MkII for cartridge swappers. How about threaded weights that can be moved in or out for fine-tuning? The magic continues! |
Bombaywalla, thanks for your report on your HiFi mod.
Another satisfied user.
This also works just as well on any Rega tonearm.
Where are all you Rega guys?
After 2 years of testing on dozens of tonearms of various types, and various cartridges, with no bad results, I'd have to say that this HiFi mod is an unqualified success.
I really think that the people who haven't tried this mod, are not fully aware of just how much better things sound, when the HiFi mod is installed. Most people who tried it were amazed at the amount of improvement. |
Well........
I finally got hold of some lead bullet fishing weights (the ones that weigh 11.42 gms) & drilled into them 1/4", as TWL himself did. Since I use a Benz L2 (static compliance 15um/mN) I chopped off the tips of these weights & brought the weight down to 9gms. I press fitted the weights using Blu-tack. Had to adjust VTF & backed down anti-skating a bit too.
Indeed, TWL, the addition of these lateral weights is a minor revelation! Bass is much deeper & tighter. Dynamics are more explosive, for sure! It appears to be the equivalent of the stylus tracking deeper in the groove 'cuz the info retrieval is much greater. The OL Silver 250 Mk1 was a great tonearm in its stock form but these outrigger weights take it to another higher level.
The only annoyance is that it interfers w/ the cueing mechanism & like you I too have to come in from the side. My old habit of going straight for the lever is dying a hard death!! ;-) |
Yes, just glue the weights to the caps for the RB250. Make sure that they are nicely centered, and also be sure that the shape of the weights you get don't interfere with the operation of the cueing lever. I found that the long tapered bullet shaped sinkers work best. You can use up to 7/16 ounce weights on each side. For higher compliance cartridges, use less weight. |
I've got an RB-250, but don't quite see how to apply this mod. There are no nuts on the yoke of the vertical bearing, just these caps. Do you just glue the weights onto the caps? |
Follow my instructions at the top of the page of this thread, and you'll have what you want. It is made for installation on a RB250.
If you have any questions about it, you can email me, and I'll help you. |
Colitas, look up higher on this thread for a post by Jimbo3 on 8/30/03. He found a product that might work on your arm. |
OK! I'm finnaly getting around to upgrading my REGA tonearm. In short I have a P3 with the RB300. I just purchased a new RB250 brand new from 2juki. I wanted to get rid of the spring and the tracking force dial. I do have an expressimo heavyweight,already. I have on order, another VTA riser(cat must have gotten the other one to play with), and the hex-treme tonearm end stub. I am going to upgrade the wiring too(another thread?) Ihave chosen to to do the work myself to keep cocts down. Anyway, any suggestions on what kind of weights to attach to the RB250? The bearing housing(I beleive that's what it is) is round, not flat! The classified ad is still in under tonearms here on the 'Gon for a picture, for those that want a reference.Any ideas on what to attach and with what(epoxy, I beleive was recommended) |
Tom, I also suggested he glue them on now that he knows the benefits. Seems like all that mass above the bearing could cause problems.
Imagine people with plain RB250/300's on any old table being able to get such a huge performance boost for next to nothing. Sad if they don't give it a try. |
Doug, I got an email from him today, showing the pics of his mod. Pretty inventive! I think that he could do away with the clamp, and just glue the things onto the side of the housing, and that would pretty it up a bit.
I'm very flattered that my idea is still breathing. I guess you just never know where something will end up, when you start a ball rolling.
I'm glad he got good results, and it just shows how universal the need is for something like this on many tonearms. I went for the Rega type arms, since there are so many of them out there. But except for 2 guys, they all went onto Origin Live Silver arms. I suppose the Rega guys just aren't interested. Too bad. It can really improve their arms. |
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Bill, thanks for your impressions. I was wondering if you had the chance to install it yet. Really glad that it is performing well in your system. Now you and the others are really getting the max out of your arms. It makes a difference to get all the performance the arm can do, instead of just some of it. The thing I like about it is that it doesn't really change the arm, it just lets the arm do what it can in a better way. You hear all of it instead of a portion. And of course, it also does the same thing for the cartridge because the arm's job is to hold it stable so it can pick up the maximum information.
Thanks for your kind words also. I feel very happy to have been able to help all of you with the sound quality of your analog rigs for such a reasonable price. I never really made any money off this mod because by the time I went and bought the stuff and worked on it and drove to the post office, it was a wash for me. But my reward was in the satisfaction that I got from helping all of you. That is why I was always so concerned about whether you got the desired results. It was worth the effort just to read the emails and posts from happy audiophiles. There is no price that can be placed on that. Those responses were worth more to me than any money. It made me feel good, and always brought a smile to my face. Money comes and goes, but happy experiences and friendship will give a lifetime of good memories. Money can't buy that.
I thank each and every one of you HiFi Mod users for your faith in getting my mod. There probably won't be many more now that they have changed the OL arm to the new type. But this has been a great experience for me, and it has truly been my pleasure to have met(by email) and worked with each of you. Keep in touch.
Tom |
Tom,I must say that I hear a dramatic difference in the bass,its seems to sound more solid and deeper,also,the overall clarity seems to be richer,like the sound has moved up to the front edge of the speakers,I'm very happy with this mod,and agree with you and everyone else that it is weell worth the cost....thanks for all your help Tom...greatly appreciate it...255/501/silver250....Bill |
Thanks Doug. I thought it would come around to that. Since the mod simply stablizes the arm laterally and cannot add anything, the cartridge will have excursion only to the extent that the recording modulates it. I knew the anomalies were in the recording.
I'm very glad that you are enjoying it. Of course, on your rig everything will show, and if there was something bad, you'd know it immediately. Nothing is totally perfect, but for $20, this has to be one of the world's best bang for the buck things ever. As the inventor I may be biased about it, but it does kick some major butt.
The voting is still unanimous. Every single person that ever used the HiFi Mod is very well pleased with the results. |
Followup review of our HiFi Mod:
I'm a bit embarrassed. After two more listening sessions, it appears the odd effects I reported above are entirely due to problems with individual recordings. Like any high end component, TWL's mod reveals more clearly what's on a record. On good recordings the effects are good, while the flaws of poor recordings are more easily heard.
In the 'Case of the Dark and Thumping Harpsichord', it seems this recording was made in a cathedral basement, in a small room with stone walls, floor and ceiling. To tone things down they covered every surface with blankets. This over-damped the HF's but was insufficient to control echoes from the bass and the action, which remain heavily reverberent. Even worse, the weather during the sessions was hot, humid and heavy. A recording made in those conditions SHOULD sound dark, heavy and thumpy. The HiFi Mod helps accurately portray the unfortunate truth.
Of course on good recordings this closer adherence to the truth is brilliantly successful. The HiFi Mod is a keeper and a winner. Another A+ review! |
Thanks Tom,
Our first couple of days with the HiFi Mod have been positive and informative. Bass is much tighter. It is considerably more impactful at the front of the note, with less overhang or bloat on the trailing end. Cello and string bass lines are much clearer and more tuneful. Heavily scored orchestral passages are more transparent, more individual instruments and less mishmash. Quite good results.
The bass is sometimes almost too impactful, we literally feel airwaves. That's great when it's a bass drum or cathedral organ, but should I feel this from the mechanical action of a harpsichord? I'm not kidding, we do. Have you ever been thumped in the chest by a harpsichord note?
It's not just about the bass. All notes are affected in the exact same way: there's more impact and body at the front and middle of the note and less overhang. In our system this change is audible even for VERY high notes like cymbals, triangles, harpshichord, etc. For harpsichord this is not so good, it reduces the last bit of bloom and color.
We're going to play with VTF and try different mounting schemes before gluing the weights on. I'd like to retain most of the bass-mids benefits while allowing the extreme HF's to stay a little more relaxed. It's possible keeping the weights from damping the bearings may do the trick, so I may try mounting them on a bar straddling the bearing yoke. YMMV of course, stay tuned. |
Doug, they can go on halfway, and that is the normal position. But they can go on all the way by reaming them a little deeper, if you like the look better that way. I sent you an email about it. I hope you got it. You're right, they shouldn't touch the bearings at all, if you seat them deeper. So be careful. |
Zaikes, I'm not familiar with the design of your arm, but wouldn't weighting one side significantly more than the other torque the bearings and potentially cause uneven wear?
Tom, I received the HiFi yesterday, thanks for the quick shipment. One question about installation: how far onto the axle nuts should they go? OOTB they cover about half the nut. Should I ream them out so they slip on further? I assume they should NOT go on so far as to touch the bearing surfaces, right?
Doug |
I haven't given this subject thought for a while, but Jimbo3's new development prompts me to wonder whether it will be problematic in any way to add the weight unevenly (or maybe 'in a statically unbalanced fashion' would be a more accurate description) about the vertical axis (i.e., in the horizontal plane). With the Rega 'arm, the added weight (at least with the lead fishing-weight method) will necessarily be kept concentric with the vertical-bearing axis, since it will be attached to extensions of the axle itself, and the two weights will be added in symmetric, statically-balanced (180-degree opposition) distribution between the two bearing-ends.
If I remember correctly, one reason I never tried this tweak with my SL-1200 tonearm (besides me already having added the KAB dynamic fluid damper, and also not being sure that the bearing-end configuration would be amenable to hosting a fishing-weight attachment anyway) was that the 'arm suspension design features a left-hand horizontal-bearing tower that would preclude adding weight to that side, due to there being no clearance available. In other words, I knew that even if I could get a fishing-weight attached to the bearing-axle end, the only place I could do so would be on the right-hand (one) side, leaving the added weight unevenly distributed about the vertical axis.
But now, thinking about how one would go about adding the maleable 'plastic' weight Jimbo tells us about, and still keep things perfectly symmetrical, has made me reevaluate the importance of this concern. And I seem not to be able to think of a reason why, with a gimballed 'arm, this would be a big deal. After all, I highly doubt that my S-shaped tonearm is statically balanced in the horizontal plane, but dynamically, this doesn't matter.
So it would seem that if I use this product to glom-on some additional weight anywhere I can get it stuck onto the vertical-bearing carriage - statically 'balanced' or not (i.e., without concern for symmetric distribution) - it would produce the desired effect of increasing rotating mass in the horizontal plane only. And indeed, it would be very easy for me to add mass this way with the stuff Jimbo used. Anybody agree/disagree with this conclusion? |
Jimbo, that just might be the ticket to use the same concept on many different arms. Thanks for sharing the tip with us. |
FYI- I found an alternative to lead which greatly simplifies adding weight. It's called "the original Sticky Weight" which is made of tungsten and claims to be 30% heavier (by volume) than lead. It is a consistency that is thicker than modeling clay and can be molded and stuck directly to just about anything. Found it at "Bass Pro Shops", one ounce for $5. Apparently, fishermen use it to quickly add weight to fishing line.
Regards
Jim |
For those that have been following this thread, I have just conducted a listening comparison with the OL Encounter against my HiFi Modded Silver arm. Basically, the Encounter has about the same effect as having the HiFi added to the Silver arm. The Encounter had an improved wiring loom, and has some other things like a tapered arm tube, that may have contributed to a slightly more refined presentation than my modded Silver arm. The Encounter sounded just a touch better overall. But the HiFi mod brings the Silver up to about even with the Encounter, with only very small difference in the refinement areas. That's the latest information available at this time. If you like the Encounter but can't afford it, then the modded Silver is a very good substitute for alot less money. |
