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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
 
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.
twl OP
3,251 posts
 
Yes, Basement I am beginning to get your drift. The stylus/cantilever must move in order for a signal to be generated. Simply having the cantilever out of line, doesn't necessarily generate a signal. But if it is out of line, then when a signal is traced, the coils will be out of center and a channel balance problem will be heard. Also the maximum deflection ability of the cart will be impaired in the direction of the side that it is off-center towards. This is a bad condition, and should be avoided. It will also cause increased record wear on one side of the groove.

The warped record I played had mostly vertical movement, and so I'm sure it was the vertical play that caused the woofer movement. I didn't try to see if the cartridge riding the warps coincided exactly with the woofer movement, although I am sure that is what was causing it. The record sounded terriffic, even though the warps were pretty bad.

The "thing that the cantilever sticks through" is called the suspension ring or donut. It is a rubber ring that is set to flex at a particular rate for the cartridge design. Butyl rubber is considered on of the best, but many types of rubber are used.

Don't forget to email me your shipping address, or I can't send you these weights.
zaikesman
3,017 posts
 
Basement, I believe you refering to the yoke.

I am getting a little lost as to where exactly this conversation is now heading, but I will make a couple of observations and hope that they will be relevant (at least to what has been written above, if not to anything important in actual practice).

1) Information in the circa 10Hz range is not intended to be transcribed in the grooves, having been mastered out beforehand. Content in this range is usually limited to warps which are vertical in nature, although a cutting lathe can inscribe rumble of its own, unrelated to the musical signal and horizontally cut.

2) The RIAA curve dictates that bass information is transcribed in the grooves at a much reduced amplitude when the record is cut, then boosted back to flat by the phono preamplifier. So these frequencies do not represent a high physical amplitude at the surface of the record.

3) As Basement implies, DC = an unmodulated groove, i.e., no signal at all. An amp will generally not pass DC, and a loudspeaker does not produce an output from a DC input. Which is to say that there is little pertinence in the notion of 'flat to DC', IMO.

4) Twl's statement about the attack of a tone rising to its fundamental before falling back to DC doesn't jibe with my own understanding. To the best of my knowledge, the attack of an ideal transient event, were it reproduced perfectly in theory, would rise in a straight vertical line over no elapsed time to a frequency = infinity, before falling back smoothly to the fundamental. In practice, transients rise very fast, over a very small span of time, to a very high frequency, before falling quickly but with some ringing back toward the fundamental.

OK, moving right along...

Kevin at KAB is sending me my damper assembly (you still here, Psychicanimal?), so I should have that in hand in a few days. He says that the paddle (which, BTW, is sourced from SME) is curved, and therefore has a damping component in both planes, although he says the vertical predominates - we'll see if that is my impression as well once I actually get it installed. Also, he says there are other paddle profiles available from SME. We had a long and interesting conversation, during which I suggested a product idea he is taking under consideration (completely unrelated to yours, Twl), and I will keep you informed if this goes further (it would likely be only of marginal interest, if at all, to folks on this forum in any case).

Awaiting Nrchy's beta-test results whenever he's a go...
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