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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
 
Basement, first, if you would like a set of these weights for your RB300, email me. They should make an improvment on the Clavis. That is not a "whippy" cartridge, and the cantilver/suspension should be quite stiff. These weights are easy to apply, and stay put, in just the right place. I really would like your feedback on this.

Next, I think I am beginning to understand what you are saying. One thing that needs clarification is your term "cantilever flexing". Is the cantilever actually flexing, or is it just moving in its rubber suspension? This is an important difference. The cantilever itself is a stiff tube, and should not flex. Flexing loses information, and imparts an unwanted resonance in the system. If the movement you refer to is small, and near the center, then it is actually suspension movement you are seeing. Flex, if it does occur, would only happen at the end of suspension travel.

If I understand you correctly, and correct me if I'm wrong, you are concerned with the very low frequencies that may be caused by warp/wow in the range below 10Hz. You feel that if the cartridge is actually tracking these frequencies, that it may be detrimental to the system, and the cantilever especially. This is because you feel that the large movements that occur at this range may bend or break the cantilever, and these frequencies should be prevented from entering the system anyway. Right? And your concern leads you to believe that the arm should move laterally at these frequencies to relieve the sidewards stress on the cantilever, and to preclude these frequencies from entering the signal chain. Right? Tell me if I understand this the way you mean it.

Now, going on the assumption that I understand correctly, you are actually referring to the matchup of the lateral effective mass/cartridge compliance. If it is minor warp or off center problems, yes the arm should move laterally on the bearing to account for these eccentricities. These problems are slow dynamics compared to the rapid lateral accellerations of the stylus during tracking of low frequency playback dynamics. An object has much more resistance to movement when a rapid accelleration is applied, than when a slow push is applied(Force=Mass x Acceleration). The slow movement of the record groove during warps and off center travel is easily handled by the arm bearing, and the arm moves laterally quite easily in this circumstance. If you are saying that the warp/off center record is causing a quick massive 1/4" or more movement that causes the weight of the arm to stay in place, and makes the cantilever move dramatically sideways because the record movement is too fast for the arm to keep up with it, then that record is a Frisbee, not a record.

My theory on this issue is this. The transducer should respond all the way down to DC. All frequencies begin at DC at the beginning of the attack, and quickly rise to the fundamental tone, and then decay back down to DC again. This is the structure of all notes. If we avoid the reproduction of the lowest octave, then we change the structure of the note, as we hear it. Even if the rest of the system cannot reproduce this, it has its effect on the sound. It is an attack, sustain, decay, timing issue. The resonant frequencies in the cartridge/tonearm cannot be avoided, but can be tuned out of the most offensive areas.

So, IMO to purposely allow the tonearm to move laterally at these frequencies, for the purpose of avoiding their reproduction, as a preventative of cantilever stress, is a counterproductive measure. It is my view that all frequencies from DC and up, should be included in the information chain of the source transducer, regardless if the other elements in the signal chain can reproduce them or not. If not, the natural structure of the tones, and the PRaT will suffer.

So, to sum up on this subject, I feel that the cantilever should be subjected to all these forces, but should remain in its properly centered relationship with the groove at all times, if possible. This may not be entirely possible, but it is a goal that we should try to attain with the improvements we are considering.

If the record is defective or warp damaged to the point of causing extraneous peaks in the frequency response at very low frequencies,or causing undue stress to the cantilever, that is a problem with the record, not the playback system. The playback system should track all the information on the record, if we are to even hope to get the best reproduction.

Regarding my unconventional thinking, it may be somewhat unconventional, but it is not original, or new. Others, such as Dynavector have addressed this directly, with an entire design(the 505-507 series) with this idea as the goal. And Graham, as well as other unipivot makers are using some form of this also. The Transcriptors Vestigal arm, addressed inertia and had 35 times more lateral inertia than vertical inertia. And the Vestigal was made in the 70's.

Hopefully, I have understood your idea, and have addressed some of the points you raised. If not, please re-explain, and I will try again.
basement
245 posts
 
Oh yes, I gotta try the weights. I would highly appreciate a set of yours, as then I can be sure I am trying exactly what you are using.
My statements regarding cantilever flex are exactly as you say. It is not actually the cantilever that is flexing, but the suspension. That can get confusing. I dont know or remember what that peice is called that the cantilever is attached to, that peice of wire, but anyway, I am observing the movement at the center more or less as you desribe.
The warp/wow that I am refering to is not nessessarily something that I would expect to tame, but the way I understand it, all combonations of arm mass and complience have or produce a resonent frequency, a frequency that is the natural frequency that will cause them to vibrate in sympathy. That is why usually the goal is to set that between the lowest frequency produced by the record, (or for clarification, the music or noise pressed into the record) and above the frequency of the warp/wow.
If the resonent frequency is in a place that is likely to get "exited" then that may have a tendancy to mask or alter the information we want.
I'm not sure if this is conventional, but I am trying to define that there is a difference in the speed of the cantilever movement and the amount of movement altogether.
I'll try to dig up some references so I can be more accurate in my descriptions and definitions, and also you can see what you think if I can find them and get some to you. I also seem to remember the SME use to have a damping trough available, so I'll have to see if any are available. The KAB site I checked out, and the damping trough seemed as though it would require quite a bit of modification for use on a rega, and zaikesman, if you are reading this, it will be very interesting to hear what this does for you.
I also think it would be interesting for us to try and measure these things. If anyone has any info on what is required, I would be extremely interested.
twl OP
3,251 posts
 
Yes, there is a difference in cantilver speed, depending on the frequency of the "bumps" in the groove that it is trying to trace. Larger amplitude bumps, in the lower frequencies, require faster velocity than the smaller "bumps" in the high frequencies, because there is more lateral deflection and return, for a given amount of rotation of the record. Also, the speed differs at the outside of the record, and the inside. The record is larger diameter at the outside, and therefore has different speed at those grooves, than the inside.
Also, I feel that the warp excitation of the mass/resonance is far less critical in the horizontal plane, because the warp movement is primarily in the vertical plane, and that is not being changed by this mod.

As an experiment last night, I played an extremely good recording by John Klemmer, recorded direct-to-disk on virgin vinyl. This beautiful record suffers from some of the most complex warping of any record in my collection. It has a dish warp, and several varying radius warps all around the perimeter(a real shame). However, I played this record on my TT(with the weight mod on the arm) and I found that the arm tracked the warps very well, and also the slight out-of-round that was there. The only noticeable thing was the woofer cones were bouncing, like would normally happen on a large warp anyway. Believe it or not, even with the intermod that this woofer bounce makes, the sound of this recording is unbelievably good, and the cartridge tracked even the most difficult dynamics like a train on a track. So as far as I can see, this does not hinder the vertical performance of the arm at all. And it shouldn't, because the design is only applied on the horizontal performance parameters. This arm with my mod, was able to track the most difficult warped record I have, and provide awesome audiophile sound quality and tracking while doing it. Just for fun, I turned on the CD player, and played one of my CD's, while I was making a cup of coffee, and it sounded like the system was broke! The sound of this TT, makes a very good CD player sound like something is wrong with it. A good record on this TT absolutely destroys a CD player, even with my best CD. Like I said, the Sony 9000ES CD player sounds like it has something wrong with it, in comparison to this TT setup. If anyone ever came over here, and listened to that comparison, they would laugh out loud.
zaikesman
3,017 posts
 
Was the CD a simultaneously-recorded version of the same session? ;^)
basement
245 posts
 
I'm glad you tried the warped record. I'm having trouble trying to explain what I mean as far as the amplitude of the movement and the amount. I'm trying to think of the proper terminolgy, bot I'm at a loss, as I have been, but I'll try to get closer. I have a feeling you might already be aware, you just can't understand the way I am attempting to explain it, so here it goes. I'll use extremes.
Say you had your anti-skate so off that it caused your cantilever to be way off to one side, (ignore all the obvious mistrackings for the sake of explaining). It would not cause movement of your bass drivers because the cantilever would be fixed. The cantilever has to be in motion, no matter how fast or slow, to cause a signal. (evan one you can see, such as movement of the woofer, but can't hear)
But if the cantilever were to move slow enough, no matter how far from center, there could be still no signal.
So while the movement of the woofer, in real use moves for something like the duration of the movement of the cantilever, it is actually the speed (technically the frequency) that is causing the woofer to move.
To get back to real life for a moment, In playing that frisby, you were able to actually observe the movement of the woofer and still get exceptional sound, yes? That indicates a good macth between cartridge complience and arm, as the warp/wow frequency was obviously present and did not affect the sound quality by causing an unwanted resonence that would interfere with the frequencies you were listening to.
You are right about this, I'm sure of- we will not ever be able to eliminate the warp/wow frequency. It will always be present and the cartridge will always be able to pick it up.
Were you able to observe movement in the catilever/suspention while this was happening? Also, are you sure that the woofers were moving to the sideways motion and not the vertical? In fact, if you follow what I am attempting to communicate, I wonder if you could observe movement of the woofer while not observing movement of the cantilever, and visa-versa.
Let me know if I am coming across, or the proper terminology whatever it is. I can't actually ever recall such a discussion ever taking place. I have more and more questions, but I don't want to confuse things to much just yet.
I found in an issue of stereophile, april 1996, (vol 19 no 4) in the review of the clavis d.c., MF gives a very thorough account of the inner workings or cartridges, this one particularly. He names many of the parts, except what that thing is called that is in front that the cantilever shoots through. It may not relate to our topic, but it may be interesting to you, evan if it may be redundant, so you could tell me more properly what the heck I'm talking about.
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