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
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.
Very glad you all are enjoying the mod.
Thank you for your kind comments.
My satisfaction comes from knowing people are getting better sound by using my invention.

Still a 100% success rate, no dissatisfaction ever reported.

This may be the only audio item that everybody likes.
It seems that the major considerations for universal appeal are:
Great sonic results,
Very low price.

BTW, I just read on the OL website about their new "Conquerer" tonearm(new "flagship model", over $4k). It seems one of the major upgrades has been to increase the lateral(horizontal) effective mass even further.
Where have we heard that before?
It feels very good to have been on the vanguard of a trend in tonearm improvement.

"H.I.F.I" = Horizontal Inertia Force Increase

Note: Remember this mod is designed for cartridges with compliance ratings of 15cu or below. No Grado or other high compliance cartridges should be used with this mod, as it does not help with a "whippy compliance" cartridge, and may cause Grado cartridges to do the "Grado wobble" because of mismatch. It gives the most satisfying results with low compliance cartridges like Denon DL103 and 103R, Shelter, Koetsu, and the like, with below 10cu compliance rating. Cartridges with 10-15cu compliance rating will get a good improvement too, but not quite as astounding as the lowest compliance ones. The lower compliance the cartridge is, the more likely it is to "overdrive" the horizontal effective mass of the tonearm, which is why the HIFI mod works so well with lower compliance. A higher compliance cartridge may likely already be horizontally stabilized by the standard effective mass of the arm, and needs no change in that parameter.
Hi Tom,
A few months back someone on VA tried to compare a 103R and a Shure V15xMR on a HIFI-modded RB250. Not surprisingly, the Shure came a poor second. I told him he'd have to remove the Mod or remove the Shure. ;-)

He apparently was under the impression his modded arm would improve the performance of any cartridge. Strange that anyone could think so after reading your first post on this thread but apparently he had missed the point, so I guess it can't hurt to reiterate.

Cheers, good to see you posting again!
Yes Doug, as you know, the HiFi mod is related to matching the cartridge to the effective horizontal mass of the arm, and can therefore be mismatched, if the cartridge has too high compliance for this mod.

It is not "universal" in application.

Thanks for your observations and comments.