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
I wanted to respond to Basements post of 10-06-02
First of all thank you for your post, a lot of thought and work went into it.
You seem to ask a question about arm movement and cantilever movement.
As Tom stated in his original post, with a low compliance cartridge like a 501,the one we both use, this demands a lot from a tonearm. The lower frequencies are always harder to reproduce because this energy is most times so difficult for the cartridge to trace. The bass energy moves the arm not the cantilever.

With the Hi FI mod you can now hear so much more bass information it is scary. This proves Toms theory that the arm is working better. The loss of those high end frequencies is I believe as you stated, really a loss of distortion, because everything is so much clearer,has more detail, more information.

I just wanted to add that I have in the past had trouble setting my VTA. This is a thing of the past, with the arm working so well it is now very easy for me to hear where the vta is best. I now have two settings, one for 180-200 grams and one for the rest.

This is another reason I like the Origin Live Aurora Table with its open design it only takes me 10 seconds to make a VTA adjustment.

Origin live states you should not tighten the base nut of the Silver Tonearm to tightly because it deadens the sound this is also much easier to hear now.

Thanks again Tom, this is truly a mod for the ages. We all struggle to improve our systems, new amps, speakers, wire cryo, you name it, but this mod does so much to improve the sound. One cannot over state it's significance. I have not heard a Rockport or Walker, but NOW, I think I now know how they sound, really its that good. I know I can improve my system more, and when I do, it will not be as dramatic as this mod, but I hope and pray that it is.
I'm real happy that you like the mod, Ron. Thanks for your great descriptions about the sonic improvements. I've even been getting some more interest from others in the HiFi mod now. Maybe it will actually "catch on" after all. I just like to improve my system, and thought others would like the nice benefits of something I figured out. Everybody seems to have the same reaction. Usually they just say, "WOW!", like you did earlier.
Hi Tom
I was reading all the responses to your tweak and got a stiff neck! I don't have the technical mastery of theoretical parameters of the tonearm's design. I have a very good intuitive understanding of the fundamental physics that are involved in a correct design, one that employs natural principles to it's function. This is the reason that I regard the frictionless "Schroeder" type of arm to be the most natural sounding which also implies that it must be the most musical sounding. The German reviewer said so when he compared it with the SME and other top quality arms. It didn't have the best base,(which is understandable given it's design) even though all the information was there, but in the concert hall, one does not hear "base" standing out, but a seamless wall of sound.
I have designed one such tonearm but I am stuck in the technical aspects of how much strength the magnets that stabilize the arm should have, so that it's inertia relative to it's mass, is not excessive. This of course can be achieved by increasing the magnet's gap so that their strength is decreased making the lateral motion easier.
What I am asking is, if there is a formula that can be understood by a layman, to calculate how strong the resistance of the arm should be in proportion to it's mass. In other words, what is their ideal ratio?
Thanks in advance!
Ted
Ted, the needed lateral mass is relative to the compliance of the cartridge suspension. The lower the compliance(stiffer), the more lateral mass is needed for proper stabilization of the arm.
Low inertia is needed in the vertical plane so as to track warped records. But many records don't have the spindle hole placed exactly right, so there is some side-to-side arm motion, similar to warp but in the other plane. Your arm modification would make that problem worse.