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
Tw1,
for some reason or another I never discover this thread. Just to add something to the discussion I would like to mention the following: I opened a discussion at Vinyl Engine which concerns the theoretic background of effective weight in the lateral and vertical direction. Some links to texts written by the famous air arm inventor Poul Laadegaard heve been added. The thread is called:How important is arm resonance frequency? Can it improve sound quality? You can find it at page 4 of the Turntable Talk part of the forum overthere.

Perhaps you know of the existance of another theoretic paper on this subject? A site by Van Alstine on the web published a similar mod mounted on the cartridge, but I think that one is not good for tracking. the thread at Vinyl Engine leads us to a last open question: how does Mr Laadegaard himself think about the 1977 AES paper at the moment? Unfortunately he is very silent about this. He did not answer my email to the B&K- office in Denmark.
Jan
Hi Janvoorn, I have read much of the writings of Poul Laadegard, and even made a prototype of his famous linear tracking tonarm once. He is an interesting fellow. Thanks for the tip to the website.

The Van Alstine mod was completely different, because it was positioned at the headshell, and affected both the vertical and horizontal mass. But, it may have helped with azimuth control on unipivots.

Actually, this HiFi mod only makes up for the lack of engineering on the part of most tonearm designers. It seems that the majority of cartridges made are wanting a bit more lateral mass in the tonearm system.
Let me ask youguys a question. I've printed out the thread and I'm still reading thru it so I hope it's not been answered before.

I'm using a very crude version of this tweak on my backup 'table, a Sony with no antiskating (the arm is a POS). It seems to have cleared things up a bit.

My take on the tweak was a thin metal spatula (what I had at hand) for which I found what I thought was the mid-point, affixed with a couple tiny drops of glue to the top of the tonearm casing. I looked at it with a flashlight from all angles and it appears to be straight.

I later made 5-coin stacks, held together with drops of glue, and added one to each side of the rod, just for the heck of it. I can't say I'm noticing much further improvement.

Anyway, about antiskating. I noticed the rod isn't quite centered on the tonearm pillar (wonder just what I was doing when I marked the mid-point on it), but rather one of the sides is hanging out more than the other.

This end is on the 'outside'. Is this the 'right' side for the offset weight to counteract the skating force, or should I mount it the other wayround?

Thanks!
Hi Damian, while the unequal weights may possibly effect a change in anti-skating, it is not recommended to do that. It has other effects too, which might include affecting the azimuth, causing unequal bearing loading, among other things. If you need to adjust your anti-skate, I'd recommend approaching it from a direction that influences only anti-skate.
Dear friend: I have around 18 tonearms. You have a point that maybe it's valid, but when a tonearm manufacturer has a good design and a good execution ( it does not matter wich kind of tonearm bearing design ) you don't have to worried about it. If with this " mod " you have a different sound maybe is because your tonearm is not first rate.
By the way, you say that a heavy tonearm is a bad traking arm ( vertical ), well this is not in that way. All depends on the cartridge/tonearm match and in the tonearm bearing.
Cheers.
raul.