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

Showing 7 responses by jimbo3

Tom et al- After considering all that has been brought up on this thread and how I could apply it to a Well Tempered table, I've come up with a simple method that might work, but I'd like thoughts/opinions from the group on it before proceeding. Here it is (You may have to look at the WT website to picture the Record Player arm)-

Quite simply, mount "X(?)" amount of the aforementioned lead tape to the the left and right side of the counterweight, but below the level of the arm tube. This would provide the stability of the "teardrop" shaped counterweight (and possibly some resonance control) and maybe a little more lateral than vertical damping. (Yes, I know it would be better to have the weight at the pivot point, but the WT arm's pivot point is unusual.)

I don't think there should be a concern about bearing wear except that the string just needs to be able to support the additional weight. (It's 12 lb test fishing line)

The only problem I foresee is being able to fine-tune the tracking force as, with the additional weight, a little movement will create alot of tracking force change. I guess it would be possible to add a fine-tuning counterweight of some sort.

Anybody care to weigh in with suggestions?

Thanks
Jim
Tom- In your tweek, the effective mass of the arm doesn't change. Doing what I propose on the WT would change the effective mass in the same way as the heavy teardrop counterweight would- correct? If so, would there be any downside? (I suppose that the length of the arm is sufficient leverage to handle an extra ounce of counterweight, though.)

Thanks for your comments.

Regards
Jim
Basement- I'm not clear on the WT arm tweak you mention of arm wrap on the base- exactly where do you mean?

I'm going to try adding lead to the bottom of the counterweight next week. Maybe an ounce (25 grams). Any other WT tweaks you've heard of?

Thanks
Jim
Tom- Would I be better off hanging a lead weight off the end stub than attaching lead to the bottom of the counterweight on the WT? Thought that lead on the counterweight would also serve to dampen vibration, something that decoupling would not achieve.

I would suppose that, if using a hanging weight, the shortest string possible would be better to keep it from swinging?
Thanks for the tips, Tom. BTW, the WT is an unsuspended table, so no worries of weight on the string bouncing around. Any ideas on vibration damping?
The arm. I thought that perhaps there would be some significant gains there, but don't know much about it.

Thanks
FYI- I found an alternative to lead which greatly simplifies adding weight. It's called "the original Sticky Weight" which is made of tungsten and claims to be 30% heavier (by volume) than lead. It is a consistency that is thicker than modeling clay and can be molded and stuck directly to just about anything. Found it at "Bass Pro Shops", one ounce for $5. Apparently, fishermen use it to quickly add weight to fishing line.

Regards
Jim