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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
 
Twl - I'll try to post here about what I find when I try the damper mod. It also occurs to me that achieving a high level of disparity between the horizontal and vertical tonearm masses is exactly what Dynavector has done for a long while now with their unusual double-pivoted tonearm design.

Animal - The ACE is below the Glider in the B-M lineup. My Glider is the current version "2" series, and has the same 6 X 40um Fritz Geyger mirror-polished stylus as is used on the $1,300 level Wood Body series, for whatever that's worth.
twl OP
3,251 posts
 
Zaikes, the Dynavector 507 was addressing this idea, and that is a good observation. My problem with the way they did it was that it introduced a whole other set of bearings, counterweights, and resonances that probably did more harm than good. What I really like about my mod, is the simplicity, and form-follows-function design. No additional complexity at all. And all of the great inherent aspects of the arm are retained, with the addition of the increased lateral stability. I'd be interested in hearing how the fluid damper mod works out for you. You may even be able to try different fluid viscosities to see which works best.

Jvr - Unfortunately I don't have a digital camera, so I can't post pics. But, it just looks like a spike sticking out from each side of the bearing housing. Perfectly concentric with the horizontal tonearm bearing axle. The arm now looks like a cross at the pivot point. That's it.
psychicanimal
1,738 posts
 
That "Fritz Geyger mirror-polished stylus" is the one my Ortofon uses--don't know about size, though. Excellent response. So, having a better cartridge than what I'm using should bring even more music once the damper is installed. I would add a little at a time and listen carefully. As for different viscosities, I'd definitely consult w/ Kevin. Im sure he's done his homework.

I can't do anything to my system yet because Dan Wright still has my Swans speakers. The crossovers should be back from Jena Labs sometime next week and Dan will do the installation and final burn-in. I don't want to change anything in my setup. Just moving to another apartment is enough of a change...

basement
245 posts
 
After reading this, I was compelled to put my table on the work bench and study my rb-300. I noticed that the nuts on the end of the vertical bearings do not move with the arm. This supports your extrordinary theory. There would be no movement in the vertical plane of this extra weight.
Then there is the damping factor of the bearings, and/or the area at them. This to me also makes perfect sense.
As if I'm not intregued enough contemplating the origin live mod, now this.
I haven't tried any of these, yet.
These questions burn in my quest for analog reproduction; How much of this tweek is attributed to the damping or manipulation of resonences at the bearing point, and how much is attributed to resistance of movement of the horizontal plane?
As far as the resistance to movement in the plane, it would seem to me that resistance to movement in both planes would be as desirable, up to the point that the cantileler would remain centered. Of coarse, while movement to the contrary would be undesirable, the resistance to movement which allows the transducer to transfer/produce the signal is critical, it would seem to me that resistance in the vertical plane would be desirable as well. It seems to me also that records seem to want to jog the cantilevel horizontally more so, or as much, as vertically, as record clamps hold the record relatively flat, and nothing can be done about records being off-center. It would seem to me in theory that benifits would be had vertically as well, if not more so.
As for adding weight for resonence control, I can't help but notice that all of the most recent improvements to the top tonearms have been in making them heavier. The emergence of the rpm, the subsequent improvement of the graham (1.5 to 2), then the added improvement by making the bearing mount more massive, (2.2).
Compared to these arms, it seems that the rega is behind in weight, and it seems that where the weight is added is important, both for resonence and resistance.
Please keep these tweeks and knowledge coming. They are HIGHLY enjoyable. It would seem the cutting edge is right here on a-gon.
zaikesman
3,017 posts
 
Basement, all tonearms already incorporate a greater vertical than horizontal resistance into their design (that is to say, beyond the biaxially uniform effective mass of the tonearm/cartridge combo itself) - the Vertical Tracking Force (VTF). Exactly how that tracking force should be calibrated is dictated by the cartridge's suspension compliance (and I would surmise cantilever length/effective tip mass), and is specified for all cart's. Correct VTF achieves the proper balancing act of allowing the stylus to accurately transcribe the vertical accelation of the grooves, while permitting the arm to respond to warps in the playing surface of the record. If you think about it, during set up of a typical tonearm, first the arm with installed cartridge is precisely balanced out by adjusting the counterweight to find the zero VTF calibration point, and then the tracking force is applied by moving the counterweight toward the pivot. Since gravity only affects the arm in the vertical plane, while the VTF is increasing, the amount of inertial mass resistance in the horizontal plane is actually slightly decreasing at the same time, as the counterweight is moved in toward the bearing center. Twl's idea adds back that leveraged mass and more, but keeps it out of the vertical plane of motion.

It would be interesting to know whether there is actually an optimum amount of resistance that should be applied in the horizontal plane, where performance would begin to suffer beyond that point, or whether more is always better up to the practical limits of the bearings, the anti-skating, the cantilever suspension, and the vinyl itself. One easy guess for a safe bet would be to add a calculated effective mass equivalent to 2X the tracking force (1X to bring the horizontal inertial resistance back up to what it was at the VTF zero point, 1X more to bring it up to equal the applied VTF point), since you already know the cart suspension can handle that. But looking at the massivity of the aforementioned Dynavector arm (the vast majority of which appears to pivot only in the horizontal plane), it seems as if it might be safe to add horizontal effective mass orders of magnitude greater than the VTF. (I suppose this is a determination that must be accounted for in linear tracking arm designs? I'm not personally familiar with any of these, but it seems to me that by the end of an LP's worth of play, a lot more mass will have been moved through a much greater distance than with a conventional tonearm.)
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