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
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.
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...
Zaikesman, I think we are all a little lost here in this, but that is what I think makes this worthwhile-A better, more sophisticated comprehention of what habbens in this area, which I think is aat the fundamentals of what makes a tonearm work well. Regarding the unmodulated groove, and the output happening in that region, is yes, caused or modulated by the warp, not something pressed into the record.
I think where TWL is on this, that I tend to agree with, is that the cartridge will, and should, be capable of reproducing this, evan as it is artificailly produced by the warp. My guess, which I'm not sure is correct, is that because it is produced does not nessesarily mean that is the resonent frequency produced by the arm/cartridge combo, but am I wrong?
Regarding the transient that you just spoke of, I don't understand this, but it may be what I am trying to understand. Could you please explain with more?
Oh, I almost forgot, the yoke, what part is that? TWL, the peice I was refering to was not the suspention component, that metal piece with the big hole in it, the one you have to look through to see the coils, often made of brass?
Well Basement, that sounds like the yoke, which would be the piece that holds the suspension donut.

About reproducing the warp, if the cartridge is held properly in place, and is doing what it is supposed to do, it will reproduce anything that excites the stylus. If that happens to be a warp, then that's what you'll get. If the cartridge is allowed to do anything else, then you will lose additional information than what you are trying to preclude from entering the system.

About the RIAA curve, the things Zaikesman said are accurate, although the bass info is still the largest bumps in the groove from what I have heard on the subject.

There is some disagreement on my "all notes start at DC" theory, but I think that is a subject for another thread.

Zaikesman, Good luck with the stuff you're doing with KAB. I hope you can get some good stuff going with them for your TT.