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
Back to the Tensegrity subject for a sec: Visited Frank Lloyd Wright's Taliesin West in Phoenix recently, and there was an obviously handmade Tensegrity sphere (composed from wooden rods with some kind of natural fiber cord and about a foot in diameter) diplayed sitting atop one of the living room tables and looking fairly old. Unfortunately, our tour guide knew nothing about the object or its provenence, but it seemed solely decorative in purpose. Could FLW himself have toyed with this construction, and also come to the conclusion that fascinating as it was, its only practical application is purely asthetic?
Zaikesman, yes I think that is possible. I have tried to build several tensegrity constructions, and they all have problems with rigidity. It seems that the wires that I used always had some amount of stretch to them, and this always resulted in flex of the structure. Very disappointing. But it is a very cool concept.
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
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.