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
Oops; the last subject line was supposed to be something about an '80s-era arm...
Well this is my first post on this forum, made plenty on others though, I registered mainly because this thread struck a chord. I have long felt that the concept of damping in the horizontal plane is sound and some time back I tried a slightly similar idea.

In my case along with a list of mods too long to go over I added a round weight over the top of the tone arm at the centre pivot, in my TT this works as there is a yoke that comes up and over the arm, so the weight sits on top of that and is actually an old video head. If you go to my webpage here
http://homepage.mac.com/braddles/Menu2.html
You will see what I mean.

Anyhow I was attampting to do 2 things, one add more mass so as to make it more difficult for the arm to deflect in the horizontal plane in response to unwanted tracking movements and secondly to kill bearing chatter in what is a pretty rudimentary arm.

Net result was that the sound was much improved, the bass much stronger and tighter and highs sweeter I would say due to the lower chatter levels. It may just be too that one of the reasons for the much improved sound others are experiencing with this type of mod is also reduced chatter as the bearing would be more stable in all directions when playing and I would say using the outrigger idea on this thread would be superior to mine in doing that.

The mod talked about in this forum takes it to another level I would say and will try it.

I feel there would be an optimum weight that would work and beyond that the damping too great so it would need careful assessing of just how much.

This concept though is also related in essence to the idea of longhorn mods on carts, which is something I have found very effective on stiffish carts. If you have a look on my web page you will see a set of pics for my "waveclone 01" cart which I built up from a very cheap cart, it has an integrated longhorn mod. (note that this is quite a bit different to the usual implementation).

The tracking with this cart is marvellously secure and it sounds way way better than it really should considering it started out as a $10.00 cart, so in I think stabilization at either end of the arm can be a good thing and they can probably work in very nicely with one another on stiff cart in basic old arms.
I'm puzzled now. The additional lateral moment of inertia is really quite low on this tweak, so that can't be all the difference. Or can it?

On the other hand, Twl has mentioned Coulombic friction, at which point it occurs to me the tweak should then work better on the OL Silver, with its exposed pivot, than on the unmolested RB250. Reasoning being, on the OL Silver the weights will damp out both the vertical and horizontal bearings, whereas on the RB250 without removing bearing covers the weights will only damp out the horizontal bearings.

On the other other hand, Zero_one's tweak clearly only damps out the horizontal bearings (and how!) anyway...

Unfortunately I can only speculate at this point because I have an arm, but no table yet...

But all very interesting...
IME with the HIFI mod on an OL Silver, the sonic improvements were entirely consistent with an increase in lateral moment of inertia. Bigger dynamics, stronger, tighter bass, faster transient response, etc.

I do not recall much if any improvement in areas that I'd attribute to improved resonance damping. No greatly lowered noise floor, no big reduction in overly resonant notes, etc. I DID hear those things when I adopted Twl's suspended counterweight, which pretty much entirely decouples the c/w from the arm. That's another story though, and it's not easily used.

Read through this whole thread if you dare. There's a lot of interesting material and experiences here. Taught me everything I know! Thanks again for the nth time to Twl for forging a path so many followed to better sound.