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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.
twl
jimbo3
304 posts
 
Tom et al- After considering all that has been brought up on this thread and how I could apply it to a Well Tempered table, I've come up with a simple method that might work, but I'd like thoughts/opinions from the group on it before proceeding. Here it is (You may have to look at the WT website to picture the Record Player arm)-

Quite simply, mount "X(?)" amount of the aforementioned lead tape to the the left and right side of the counterweight, but below the level of the arm tube. This would provide the stability of the "teardrop" shaped counterweight (and possibly some resonance control) and maybe a little more lateral than vertical damping. (Yes, I know it would be better to have the weight at the pivot point, but the WT arm's pivot point is unusual.)

I don't think there should be a concern about bearing wear except that the string just needs to be able to support the additional weight. (It's 12 lb test fishing line)

The only problem I foresee is being able to fine-tune the tracking force as, with the additional weight, a little movement will create alot of tracking force change. I guess it would be possible to add a fine-tuning counterweight of some sort.

Anybody care to weigh in with suggestions?

Thanks
Jim
twl OP
3,251 posts
 
Jimbo, you can do what you are proposing, and it will improve the sound to some degree.

The improvements, however, will come from the lowering of the center of gravity of the counterweight, and not from increasing the horizontal mass component of the tonearm. This is because when you increase the mass of the counterweight by adding the lead tape, you will have to move the counterweight closer to the pivot in order to balance the cartridge. As such, the mass components as the cartridge sees them, will remain the same, or at least very similar. But lowering the center of gravity of the counterweight by adding the lead tape will improve the tracking of the cartridge and I suspect the improvement will be audible.

Due to the things I mentioned above, I think that adding the lead tape at the very bottom of the counterweight would be the most productive place to put it, in terms of making the most sonic improvements. If you have to make several layers on top of each other, to get the desired effect, then that is what you should do. Bringing the majority of the counterweight mass down near the level of the platter is known to improve the tracking performance.

However, I don't think that it will do anything for increasing the horizontal mass component. But hey, any improvement is worth doing, right? It's innovative, and cool to do your own tonearm mods.
jimbo3
304 posts
 
Tom- In your tweek, the effective mass of the arm doesn't change. Doing what I propose on the WT would change the effective mass in the same way as the heavy teardrop counterweight would- correct? If so, would there be any downside? (I suppose that the length of the arm is sufficient leverage to handle an extra ounce of counterweight, though.)

Thanks for your comments.

Regards
Jim
twl OP
3,251 posts
 
Jim, there would be no problems, as long as you don't make the mass of the counterweight so high as to not be able to move it close enough to the pivot to allow counterbalancing of the cartridge. The heavier you make the counterweight, the closer it must be positioned to the pivot, in order to balance the arm. At some point, you can make it so heavy that you run out of room to move it forward on the arm, because you run into the bearing housing. That's the limit. Put the additional weight at the bottom where it will do the most good for lowering the center of mass.
basement
245 posts
 
YEAH!! I dig tweaking. It sounds like your ideas should work real well for a # of reasons, so here is my pre-feedback on your proposal- I have had great success adding lead to the couterweights of all the arms I have tried it with. My origoinal goal was to increase the mass of the arm (If I recall correctly, it was because I read that this was a tweak applied to the well tempered arm, replacing the counterwieght with a heavier one). When considering this keep in mind that there is a difference between what is referred to as effective mass and mass. Effective mass is the 'effect' that the mass has on the inertia of the arm. As twl states, increasing the mass of the counterwieght and moving it closer is a perfect example of increasing mass without changing the effective mass. Twl's mod is an example of the opposite- the mass applied at the pivot changes the effect in the vertical plane very little, while the effect on the horizontal is increased disproportionally. So, if you were to consider a graham arm with adjustable sidewieghts, and spread the sidewieghts out from the pivot equally, the mass does not incease, but the horizontal effective mass increases because it then takes more force to effect movement in that plane. The vertical effective mass remains unchanged because the weight remains at the same point relative to vertical movement.
The reason I go into this so much is because if you see a picture of the newest version of the immedia arm, you will notice that mr. perkins has moved to a scheme that has the counterwieghts extended out to the sides. He has increased the effective mass in the plane that effects azimuth.
The immedia is a unipivot, so stability in this area is important, and the well tempered is also a unipivot, with a very similar damping scheme.
The rb-series is not a unipivot, so the azimuth is fixed, and while the aftermarket counterwieghts do move the mass of the arm lower, I wonder how much of the improvement is because the mass is lower, or because the properties of energy absorbtion. With a counterwieght that is perfectly round with it's energy transfer dead center, the energy would be reflected back equally and at the same time, and if the point of energy transfer is off center, this may serve to be an effective way of breaking this up. As evidence I would point out the reported success of mods that change the tension of the rear stub of the rb-type arms and they're success relative to these droppoed counterwieghts.
And also, regarding mass for benifits of energy absorbtion, One of the best tweaks for the well tempered arm was arm wrap on the base, and also, the immedia arm first had a base that was very similar to the base of the well tempered arm, until it was changed to the heavy stainless piece it is now, and the success the graham 2.0 has because of it's heavier base over the 1.5.
I am looking foward to hearing about your results.
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