Doug, As regards the drastic reduction of the anti-skate weight on the Triplanar, do you recommend it for all cartridges or only those with line contact styli?
I have a Koetsu Urushi, which I would guess has an elliptical stylus. Does anyone know for sure? |
Thanks, Doug. Sirspeedy, you must live in the DC metro area, as I do. I too was a longtime friend of Herb Papier's, and my experience of him was much the same as yours, i.e., a great guy. I met Tri Mai at Herb's house, when I went there to have Herb upgrade my Triplanar to a Mk VII. Tri was learning how to make the product at Herb's side.
Sorry for the off-topic blather. |
I am with Glai. On my Triplanar with a Koetsu Urushi, the sound is very problematic with zero anti-skate. (But I have not removed the device from the tonearm, so I cannot comment on the putative benefits of doing that per se.) With AS set to zero, there is considerable distortion in the R channel and also a channel imbalance with respect to gain. Also, Palasr, I was interested to read that you found you could reduce or eliminate AS by increasing VTF a tiny bit. I cannot remember the formula for estimating skating force, but I thought VTF and skating force were directly proportional, so it seems odd that increasing skating force by increasing VTF would decrease the need for AS. (Maybe I am incorrect about the relationship between VTF and skating.) |
Found this quote on Audiokharma, from someone named "Marcmorin":
"...the higher the friction of the stylus in the groove the MORE skating will occur. Groove friction is the driving force behind the skating behavior. The mathematical derivations should make that clear. It's the friction of the groove pulling on the stylus that tries to turn the tonearm around its pivot towards the spindle. More friction = more turning effort (torque or moment). Less friction = less turning effort. Groove friction is directly proportional to VTF since it is VTF that presses the stylus against the groove. More VTF = more friction force = more antiskating required. Less VTF = less friction force = less antiskating required."
Note, skating force is proportional to groove friction, and groove friction is directly related to VTF. My memory neurons are still firing, thankfully. |
Glai, I guess I failed to express myself properly. When VTF goes up, skating force goes up (not down, which in my parlance would be an "inverse" relationship). Likewise, when VTF is decreased, skating force will decrease. This is on average, across the entire surface of the LP. The defense rests.
My point was that Palasr's report that he increases VTF to mitigate issues that arise when he decreases AS are contrary to the physics. But other things could be going on that contribute to what he is hearing. |
(1) All I'm saying is skating force is proportional to VTF. The word "proportional" in a mathematical term only means that they increase or decrease in relation to one another, which relationship may not be perfectly linear.
(2) Just about any tonearm instructions I have ever seen from any manufacturer will advise setting AS at some value below that of VTF, so no one would argue with that, least of all me.
(3) Glai, I think it is more correct to say that MORE tracking error reduces skating force, not less. The whole reason we contend with skating force is because the headshell is offset at an angle to the arm tube to minimize tracking error. This is what generates the skating force. If the headshell is not offset at an angle to the arm tube, then there is no skating force but lots of tracking error. In a 12-inch tonearm, this effect is somewhat ameliorated compared to a 9-inch one. That was the rationale for the Nottingham 12-inch tonearm with no headshell offset.
I agree with you guys; I do use the very most minimal amount of AS necessary to overcome that R channel distortion and to give even channel balance. I am not sure what Glai was trying to convey in his discussion of imaging, but I think we agree; I hear the musicians kind of get squooshed together on the R side. My observation was made with my Triplanar, but I also observed similar phenomena with a Dynavector DV505. With the TP, I need to try the tiny O-ring idea.
I think the way in which the cartridge is a determinant of the need for AS is only due to differences in stylus tip shape and mass. Those factors affect groove friction. Groove friction and VTF are all that should matter, for a given offset angle of the headshell. |
Dear Glai, You wrote:
"Consider a linear tracking arm which the headshell is not at an offset. For your statement to be true, there would mean no skating force and maximum tracking error. How could that be?"
My response is... What? My statement IS true for pivoted tonearms. It's not merely my opinion; it's a fact. The case you cite is a red herring if every I saw one. Pivoted tonearms in principle present us with this dilemma of a trade-off between tracking error and skating force. Linear tracking tonearms avoid the issue altogether, but by their nature they present new and different issues, as I am sure you know. |
Dear Glai, If you are asking me, try searching the Vinyl Asylum for discussions of skating force. Some pretty knowledgeable guys used to post on these topics, altho of late (the last year or two) most threads are about trivia. Or, try Google.
AFAIK, the various tonearm alignment geomtrys (Stevenson, Lofgren, Baerwald, etc), are about where to place the two possible null points along the path of the stylus from outer to inner groove, and to minimize average tracking error in between those two null points. (Where "null points" means points where there is zero tracking error. You can only have two of them in an arc traversed by a pivoted tonearm.) The Stevenson geometry happens to place the innermost null point closer to the spindle than any other standard geometry, which is why Stevenson is not commonly used any longer, or so I was led to believe; most tonearm designers favor placing the null points toward the outer groove for maximum fidelity. The various geometrys will affect skating force insofar as the optimum tonearm offset angle will be different for each geometry. I'd have to think more about that, though. |
