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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
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.
jimbo3
304 posts
 
Basement- I'm not clear on the WT arm tweak you mention of arm wrap on the base- exactly where do you mean?

I'm going to try adding lead to the bottom of the counterweight next week. Maybe an ounce (25 grams). Any other WT tweaks you've heard of?

Thanks
Jim
twl OP
3,251 posts
 
Basement, regarding your thoughts on counterweight mass and absorbing vibrations, I have developed a new hanging counterweight for my arm that totally de-couples the mass from the arm, and the only thing that contacts the end-stub is a short length of fishing line. The counterweight is a lead bar that hangs under the end-stub like a swing, at the height of the platter surface. I have found that this beats the holy hell out of the Expressimo Heavyweight on my arm, and I am using it exclusively now. The sound is way more open and unencumbered, and really kicks ass. In my case, I found that getting the mass of the counterweight off the tonearm shaft entirely, really opened up the sound. With this counterweight and the HiFi mod, I am really in the top league with this tonearm now.
jimbo3
304 posts
 
Tom- Would I be better off hanging a lead weight off the end stub than attaching lead to the bottom of the counterweight on the WT? Thought that lead on the counterweight would also serve to dampen vibration, something that decoupling would not achieve.

I would suppose that, if using a hanging weight, the shortest string possible would be better to keep it from swinging?
twl OP
3,251 posts
 
Jim, the hanging counterweight is good on my arm, but I don't know how it will affect the Well-Tempered. If the turntable doesn't bounce around much, it may be ok. It is not too good on Linns and tables that have springy suspensions. Also, if you are going to try it, I'd recommend using a rubber O-ring slid onto your end-stub at the correct place, and using that to stop the string from sliding backwards when you cue the tonearm. I found that without the O-ring as a "stop", the string wants to ride backward on the tonearm when you cue it, and then you lose your VTF setting, and it is a pain in the butt. The O-ring placed behind the string, at the correct point for the proper VTF setting, keeps the string from sliding and will retain your VTF setting, and is much more pleasant to use.

It is worth a try to use the hanging counterweight. It's cheap and easy to fabricate. If it doesn't do well in your application, it's no big loss. You can always go back to adding weight to your existing counterweight, like you were going to do.

The main idea is to hang it like a swing, with the string going across the arm tube, and holding the counterweight cross-wise, so it doesn't rotate around. Just hook the string to both ends of the lead bar. This works in my application, and the rubber O-ring keeps it in place on the end stub. It takes a little fiddling to find the exact place on the end-stub for the O-ring to be, but a few minutes with the VTF scale, and some very fine placement adjustment of the ring, will give you the proper spot. Once this is done, you can even totally remove the counterweight, and then replace it with the string against the front edge of the O-ring, and you have the same VTF setting. It is like a place holder. It just stops the string from sliding backwards. It isn't a clamp for the string, just a slide-stop.

Make the lead bar the same, or slightly heavier than your existing counterweight. Make the string the right length, so that when you hang the weight on your end-stub, the lead bar is about at the same level as the platter surface. Then slide the O-ring onto the end-stub, adjust the position until you get correct VTF with the string right up against the front edge of the O-ring. That's it.

Hopefully, there will be no parts of the tonearm housing that will be in the way of this during use. If there is, then you have to modify, or go back to Plan A.
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