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
Thought I'd drop by.

My Jelco arm (think MMT, Audioquest, Graham Robin)doesn't have the capability of pressure-fitted weights like the Rega. But on each side of the bearing housing I thought there might be room on the sides for something, small flat spots where bearing adjustment "screws" are located, so I thought some more for something that I could do fast. The arm is mounted to a restored Russco Mk V, with a DL103 cartridge.

A few minutes later I glued six quarters into two groups of three, face to face, with a hot glue gun. Used the same hot glue to attach the quarters to the spots I referenced above. Totally reversible as the glue stays a bit soft after curing and peels off of metal with just a bit of effort.

Shazam! The effect seems exactly as described in your initial post from five years ago. I may engineer something a little prettier in the future, but the 16.5 grams or so on each side (each quarter is 5.5 grams)works very well with this arm (and presumably variants of it like those mentioned above). I don't know if the greater weight (compared to the fishing weights) compensates for their shorter lateral reach (compared to the fishing weights), but that was my thought when gluing three quarters together instead of two.

If anyone is curious I uploaded an image here--http://new.photos.yahoo.com/deanmanjames2003/album/576460762310128890

Comments, suggestions welcome!

Jim
Has anyone tried and listened to differences. I would prefer to use tungsten bullet weights instead of lead due to toxity of the latter.

Any sound difference?

Roger
Hi guys.
It's been a long time, and I've been away from the site.

I'm happy that some of you are finding out what this mod can bring to your music.

Regarding the Townshend with the silicone damping trough, yes the damping is having a similar effect but in a different way. That is probably why the effect of the mod wasn't as noticeable in that case. Being that the silicone trough is up at the headshell area on that TT, the stabilizing effects will be nearly immediate in that case, but not quite immediate. That is likely why the TWL mod was still giving some benefit, but not as much as usual.

I'm still getting a chuckle that after all these years, people are still finding out about this thing, and getting amazed by it.
It's a very simple application of basic tonearm design, that seems to have eluded the tonearm manufacturers even to this day.
Too bad I can't get rich off this idea. But, if people can enjoy better sound for next to nothing expended, I guess that is reward enough for me.

And yes, the tungsten weights or other types of weights will work just fine.
...that purposely increased lateral mass over vertical:
http://www.kabrna.com/hifi/orion_tonearm.htm

Still a great idea, though, to separate the two resonance frequencies, and lower the combined peak.
Oops; the last subject line was supposed to be something about an '80s-era arm...