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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
twl OP
3,251 posts
 
Stefano, thanks for your question, and I'm glad you enjoyed the thread.

In my opinion, a cartridge with a compliance of 25 is not going to move the RB250 laterally. The standard effective mass of the RB250 should be sufficient to laterally stabilize that cartridge.

I don't think that adding any additional horizontal mass would be productive in this case, and there is a possibility of causing a mismatch in mass/resonance if you do add horizontal mass to the tonearm with a high compliance cartridge, such as you have.
4yanx
1,576 posts
 
In a purely aesthetic vein, I was in the store other day to find weights for my OL Silver. In the store I visited, there was literally an array of lead and brass weights in a variety of colors. Black, which matched my arm perfectly, gold, silver, tortiose shell, neon colors. Some looked VERY cool. Guess the fish can tell a difference too!

I JUST set up the arm the other day with a Denon 103R. Tried it sans weights first and things were pretty damn good. Then, last night, I took two 1/2 oz. weights and drilled out the centers a bit and matched their weights on a digital scale until each was 11.75gr. Installed and spun again. OK, this invention is probably the biggest bang for the buck (well, actually cents) in the history of audio. The additional detail was not to be believed unless heard and the tightening of the bass was kinda scary. So much so that I wondered if it could actually be attributed to such a seemingly meager mod. But, I am not willing to take them back off to find out.

Bravo, Tom! Good work!
twl OP
3,251 posts
 
Thank you David. It means alot to hear accolades from someone who has heard as many analog products as you have.

That makes me feel real good!

And I'm happy that you got good results, too.
4yanx
1,576 posts
 
Your welcome. Looking forward to even better things as this cart breaks in, too.
twl OP
3,251 posts
 
FWIW, I invented this mod because I cannot play in the upper stratosphere of high priced tonearms and other equipment. I have a budget, and so I only tried to make the most of what I could afford to buy. I have also tried to do stuff like this with my other equipment, so that I could have as close to "top end" sound as possible, given my low budget for purchasing. Necessity is "the mother of invention".

I would urge anyone who likes this HiFi mod, to experiment with Lowther single-driver speaker systems and low-power SET amps. That combination makes an exceedingly enjoyable result at the back-end of the signal chain too.

The mods that I've made to my Lowther EX4 equipped Voigt pipe cabinets makes a significant improvement to that design too. And the cone treatment that I used is very effective in virtually eliminating what is left of the "Lowther shout" from the current version of the Lowther speaker drivers. My cabinets only had one very noticeable flaw(within their intended spectrum range), which was a "hollow sounding" coloration in the lower mid-bass, from some cabinet resonance effects. This was totally eliminated when I placed the Sistrum SP-004 platforms under the speakers. It was miraculous in eliminating this resonance from the cabinets, and was one of the major factors in my eventually seeking employment with Starsound.

A well-tuned Voigt Pipe with Lowther drivers, using my "swinging doors" baffle mod, and placed on Sistrum SP-004 platforms, is one of the most musically enjoyable speakers that could be had for the money spent. Of course, my custom David Berning 45 SET-ZOTL is a very nice way to drive them, but any good quality SET of under 8 watts(with good output transformers) would be a nice pairing with these speakers. I am transfixed by the sound quality every time I play my system. It always puts a smile on my face, and sometimes I even have to get up and dance in the room.

I only say this, because most people have liked my tonearm mod, and I want to share some of the other things in my system that have given me equal improvement to my listening pleasure. I'm not going to make any speakers for sale, but the plans are on the internet, and anyone can email me for info about the mods, or proper tuning procedures for the Voigt Pipes, or the cone treatment.

Basically, the mods relate to eliminating the baffle-step losses associated with narrow-faced speaker cabinets, without resorting to electronic filtering, and the cone treatment stiffens the cone without adding mass which would slow down the speed. This changes the cone-breakup mode which coincides with the transition from main cone to whizzer cone in the critical upper midrange which is generally called "Lowther shout". It solves it. The SP-004 platforms are required to eliminate the cabinet resonance in the mid-bass region that happens because the lower half of the Voigt Pipes must be hollow.
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