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
I believe!!!

For less than $5, I purchased 2 fishing weights from the Bass Pro Shop and some Blu-tac equivalent from the Home Depot. It took 3 attempts to figure out how much blu-tac equivalent (actually, mine is yellow) to use, but I no longer feel the need to pull out the super glue. The weights haven't slipped for a week now.

I have noticed that my OL Silver / Shelter 501 is now even more sensitive to VTF (1.85 grams by my Shure seems to work best for me).

If you have an arm / cartridge that could benefit from this tweak, you are a fool if you do not try it. For less than $5, this non-permanent mod is a must.
I found this thread from a post today on the AA Vinyl Asylum.

Anyway, I came, I read, I tried the mod. I have an RB250 with the OL stub/counterweight, OL rewire, etc. I just superglued the 7/16OZ bullet weights to the bearing caps and got on with it. The results...

Wider and more 3D soundstage, initial bass impact is much snappier (but not deeper). Its like everything became more focused. The highs got a lot better - I had no idea how mushy my setup was before. Good stuff.

But the best improvement is that well-recorded pianos now have that chesty piano sound, instead of a throaty piano imitation. Real, full, reverberant piano. Shweet.

Thanks TWL and all for the best $.79 I've ever spent in audio.

Pete Fowler, Austin TX
Tried this with my Rega P25/RB600/cart setup and it works great. Used the yellow "blu-tack" mentioned within the thread, and steel bullets (can't find any lead ones in NH, but if someone whats to ship me a pair, feel free to send some up here!). I also have a Denon DL-103R on order, and am interested to see how the tweak works when the Denon's installed. I know the DL-103R isn't supposed to be the perfect match for the P25/RB 600, but thread comments have convinced me using this tweak with the Rega will prove otherwise.

What a great low-cost removable upgrade - thanks!
To all, and TWL especially - changed over my cart to a Denon DL-103R, with the bullet tweak previously installed. After setting up and burning in the cartridge (TWL - no VTA adjustment needed on the Rega!), I can easily attest the DL-103R with the tweak is a wonderful match. This cart nearly nailed the HFNR Test record's torture track, and IMHO that is saying something. What a pleasure to listen to, and I'm happy to have the $$$$ in my pocket that I could have spent on much more pricey carts. TWL, thanks again for the recipe and advice, esp. on the DL-103R.