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
Viridian - I already use the Expressimo Heavyweight, and found that to be a very good improvement also. I did not consult Origin Live about this, and am quite sure that they do not consider it necessary. This would be the typical response from manufacturers. I feel confident that this mass, in the way it is applied, will not compromise the bearing integrity. If anything, I believe that it may enhance the bearing life, due to chatter reduction, because of the increased mass of the bearing axle and lead damping.

Todd - I think that the lead dampening effect on the bearing axle is a benefit of this mod. As I said to Viridian, this added weight and dampening will decrease chatter by raising the chatter-motion threshold above what the cart can put out. Thanks for the offer of lead ribbon, but I already have some. I have not tried it on the arm though.

Dekay - That is correct. The lead weights are like extensions of the tonearm bearing axle and are outside the bearing housing, so it is not affecting the effective tonearm mass/resonance. They also have minimal effect on the vertical movement because they are small diameter, and concentric with the center of the axle. Therefore the moment of vertical inertia is hardly affected at all, but the horizontal moment of inertia is greatly increased. The only change to the loading of the vertical pivot bearing is on the thrust face. The total increase in weight is only 24 grams, but the wide positioning of the weight is the key to increasing the moment of inertia required to move the arm. This is what really stabilizes the arm to the movement of the cartridge. And man, does it work!
TWL: Very interesting, though I cannot see an "easy" way to try this with my old SME (short of Super Glue:-)
Very interesting approach Twl, but the analogy between stabilizing outriggers on a unipivot design arm and what you've done for your gimbal bearing design arm is somewhat incomplete. Azimuth control should not be a problem with quality bearings in a gimbaled design, but you don't seem to be affecting the center of gravity with your implementation anyway (unlike those "dropped" counterweight Rega retrofits). It seems to me, what you've really accomplished is most similar to what a viscous damping trough arrangement can do, albeit perhaps with lesser attenuation of high frequencies. The goal is to increase the tonearm's resistance to lateral deflections that occur at much higher velocities/frequencies than just the spiral groove's dragging the arm across the record, thus increasing the amount of information able to be transcribed accurately by the stylus. It does seem as though you've hit upon a simple, inexpensive mod to accomplish just that, although I'm curious as to why your mod would actually increase susceptability to skipping - like a viscous damper, it seems as though it should in fact decrease this tendency, since a skip is basically a rapid lateral deflection of the arm. For my decidedly non-audiophile-approved Technics Sl-1200, I intend to soon order a dedicated retrofit viscous damper assembly from KAB, and I hope I'll hear some of the benefits with my Glider that are blowing you away.
Quote: "For my decidedly non-audiophile-approved Technics Sl-1200, I intend to soon order a dedicated retrofit viscous damper assembly from KAB, and I hope I'll hear some of the benefits with my Glider that are blowing you away."

You mean "non-Voodoo approved". A true, knowledgable audiophile like Bill Parish, Dejan Veselinovic, Thorsten, Sedond or *yours truly* will admit it's a good TT. Not to mention the one (electrical engineer) member here who modded the Quartz Lock circuit board in his'...

And yes, adding the fluid damper WILL blow you away. Everything will seem it's happening in another time continuum. Get ready. I can play the innermost grooves of a Barbara Streitsand album w/ no breakup whatsoever using a modest Ortofon X5 MC. With a Benz Glider expect even higher performance and speed.

From TWL's experiment now I understand why Kevin Barrett does not want the fluid trough filled more than halfway. He's aiming, then, at achieving lateral damping over vertical. That also helps explain the shape of the paddle. Good, I just received a srynge full of silicone for refilling (I relocated), so I'll add a little at a time and listen carefully. Very well. Just when I thought I knew it all...

Life is good.
Geez, PsychicA, didn't take long for my post to pull you out of the woodwork...You mean after all this time you didn't 'get' the principle of this gizmo you've been all over me to go ahead and order?! Well, just so's I don't earn one of your 'encouraging' emails tonight, please know that the only reason the damper's still pending in my set-up is because of my recent move - combined with some more urgent upgrade necessities mandated by same, which I now believe I have adequately filled. I promise to get on the phone to Kevin soon... :-)