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
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
Jimbo, that just might be the ticket to use the same concept on many different arms. Thanks for sharing the tip with us.
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?
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
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.