2. analog
  3. 1032024188

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
zaikesman
3,017 posts
 
Actually, Nrchy, what Twl said was that he was 'a little different' (than what, I don't know); *You* said he was a little strange (but who am I to aurgue?). ;^)

I find it very interesting [Sorry to interupt, but y'know, whenever I see that phrase, 'very interesting', around here (and I use it a lot), I can't help but say it to myself in that faux-German voice Artie Johnson said it in on Laugh-In as he peered through the bushes with his binoculars. Do you think I have a problem? Or maybe I'm just...'a little strange'?] Uhmm, where was I - Oh yes, I find it very interesting that Nrchy and I have seemingly arrived at fairly divergent sonic assessments regarding the tweaks we enacted (I just went back up top to reread Twl's original post, but all he specifically remarks on is increased 'dynamics and detail'). This could lead one to believe that the two tweaks (horizontal mass-increase damping, and fluid damping) are really not that closely related in the ways which they operate. Thinking about it, I'm actually surprised no one has offered (to the best of my knowledge) a retrofittable fluid-damping kit for Rega 'arms, considering how ubiquitous the design is. Another market?

Twl, your idea about the VTA-correcting double-hinged 'arm, while not persuasive to me as such (wasn't it you who said something to me, someplace earlier up this thread, about not getting too complicated - besides, I'm still not convinced that a momentary VTA error of a few degrees during a warp is really a big deal), reminds me of another variation on this theme. I believe I remember a design, probably from the 70's, and probably not all that up-market (although I can't think of who actually may have made this for the life of me), wherein the headshell was hinged on a bearing permitting it to rotate in the horizontal plane, and a separately-pivoted (from the tonearm) 'control arm' was employed, not quite parallel to the tonearm but running alongside it on the outside and swivel-attached at the headshell, for constant correction of the headshell's offset angle as the tonearm moved across the record, through a slight 'parallelogram-ing' action. Anybody know what I'm talking about here ('cause I'm not at all certain that I do!)? I do agree, Twl, that something along the lines of a wishbone, truss, or I-beam design would have to be enlisted to make an extra-long tonearm as rigid and non-resonant as it would need to be.
twl OP
3,251 posts
 
Nate, I'm very happy the mod was effective for your application. This lets me know that the mod is applicable for different compliance ranges, and that is good. My initial assessment of your results compared with mine, is that your compliance is higher, so the bass dynamics were not as affected as mine(lower compliance)was,but the general information pickup was improved. With my stiff compliance, the arm is more likely to be pushed around by the stiff suspension on the cantilever. But the fine detail, air, and authority of piano,bell-sounds, and such, is also improved on my arm with the mod. So now we know that it works on an OL Silver with DL103, and RB900 with Benz Glider. Basement's rig is a RB300 with a Lyra Clavis, so we'll see how that one does.

See, sometimes being a "guinea-pig" Beta tester can be very advantageous. You are presently the only other person in the world with this mod, besides me. Basement is the next victim, and his test units are going out in the mail today. I couldn't go down to the store to get more weights until yesterday. :^)
twl OP
3,251 posts
 
Zaikesman, the articulated arm you referred to was the Garrard Zero-100 Zero Tracking Error system. I had one of those in the early 70's. The main problems were cheap construction and implementation. The system itself could work with modern materials like carbon fiber and a quality implementation.

I would agree with your assessment that the fluid damping and the horizontal mass modification seem to have different characteristics, even though we speculated that they might have similar ones. Perhaps a combo of these two might prove to be beneficial.

Yes, I knew that a 4-8 bearing setup on a double wishbone for the headshell would be overly complicated, but I was just dreaming about the exotic. I also dreamed about using a Buckminster Fuller tensegrity column for the arm, in which all forces would be resolved in the tension/compression design. Way too complex, but fun to think about, if you are "strange" like me.
twl OP
3,251 posts
 
Just to make an announcement, this mod now has an official name. It is called the HI-FI(Horizontal Inertial Force Increaser). Assuming a positive response from Basement, I will begin to look into a market for these products.
zaikesman
3,017 posts
 
I've always wanted to see a tensegrity application for some common practical purpose, but there is none I'm aware of. It's just so damn cool, I want tensegrity to be good for something beyond spheroid toys and Kenneth Snelson towers. I doubt a tensegrity stucture would really be useful for a tonearm, but I have wondered whether it may be helpful as an isolation suspension device for components, maybe even TT's.
More to discover