First, Thank you Quiddity for explaining the skating force. I understand it now.
With the RS-labs arm, however, the suggested alignment results in the elimination of skating force at one point (suggested by the manual to be slightly 'inside' (toward the record spindle)) of the grooved surface of the record. At this point, the stylus and arm are perfectly tangential to the groove. For tracks at the outside of the record, the skating force is slightly outward, while for tracks towards the inside the skating force is slightly inward.
Quiddity listed an 'offset' of approximately 95 mm for a typical tonearm wrt causing the skating force. For the RS-labs arm, this is no greater than the about 45 mm at worst. Thus, the skating force is significantly less than for other tonearms.
If you use the RS-3 headshell, and if you wanted similar benefits as for the RS-labs tonearm, you would have to increase the distance of the tonearm pivot from the spindle. The RS-labs arm is set up with underhang, not overhang.
Also, when I had an RB300 and a Syrinx PU3 tonearm, you could hear the music by listening to the cartridge in the groove directly (with the sound on the preamp/amp turned off). This was quite clear, albeit with the RIAA emphasis. With the RS-labs arm, it is almost impossible to hear this. The pivot appears (to me) to eliminate/minimize the transfer of energy from the cartridge into the tonearm. This might also be why it sounds the way it does. |
I should add here that I heard the RS-A1 at Dave's house and was similarly impressed, since I was familiar with the sound of Dave's system as a baseline. Very lively and therefore life-like is the best way I can sum it up. To paraphrase what Dorothy Parker once wrote about the emotional range of the young Katherine Hepburn, the RS-A1 runs the gamut of sound tonearm engineering, from A to B. But the darn thing works. |
Good luck in your quest. I had something of the same feelings, as I read the impenetrable installation and operating instructions on this arm, plus Art Dudley's rather mystified review in the old Listener magazine, finally decided they were never going to make any sense and just relaxed and enjoyed its musicality and sonics.
But not its ergonomics. You need a lot steadier hand and better eye-hand coordination than I have to subdue this thing. Dave |
Hey Dave, I'm TRYING to understand the wonders of the RS labs approach to design, but so far I've had no joy as no-one has been able to explain how they work. Several explanations have been advanced but so far they've all been proven wrong.
For me "just listen to it" doesn't cut it, if a device produces good results I want to know why. By that I mean why the designer dreamt it up and how he made the decisions he made. |
'Nycewine1', did your dealer mention anything about the RS-3 being designed only for straight tonearms? I only mention it because a poster on another thread claimed it to be true.
I'd love to try one myself-btw, on what table, and with which cart, are you using it? |
All well and good, Quiddity, but you seem to have misunderstood the wonders of the RS arm :-)
I can't blame anyone for doing this. You have to use the silly thing. I wouldn't have believed it either. Dave |
Juliejoma you have misunderstood skating force. It has nothing to do with the angle of the headshell except that this angle attempts to follow the offset of the pivot.
The stylus reaction force is a vector. The direction of the vector is a tangent to the groove. The vector does not pass throught the pivot of a pivoted arm. The distance between the vector and the pivot forms a torque arm with the stylus friction. This torque is the skating force. The length of the torque arm is equal to the linear offset of the tonearm (about 95mm in Baerwald's alignment) and this is nearly constant regardless of the angle of the headhsell / cartridge. |
There is no need for anti-skating force because the stylus is perpendicular to the armtube. The reason you need anti-skating for offset headshells is because the elliptical/line stylus is rotated by between 19 degrees and 23 degrees from the line that goes from the stylus to the pivot point. With the RS-labs arm, the stylus is always perpendicular to the line that goes from the stylus to the pivot point.
For an analogy, think of paddling in a canoe. If you are at the back of the canoe and place the paddle in the water directly behind the back/stern of the canoe, but put the paddle in 'at an angle', the canoe will turn to one side or the other. This is like the lateral 'skating force'. Think of the angle at which you dipped the paddle as the offset angle of a regular headshell.
If you place the paddle in the water perfectly perpendicular to the canoe, the canoe will slow down, but will not turn. This is like the RS-labs headshell. There is no sideways drag due to the stylus.
Now, the stylus does not follow the angle of the cutting lathe as it covers the vinyl groove as well as an offset headshell, which creates some phase error, but the RS-labs arm more than compensates for this with the lack of resonance from the actual armtube.
If you can't already tell, I love my RS-labs arm. |
Thanks, Quiddity, for correcting me. I am guilty of believing the box that the RS-A1 comes in, rather than thinking about what is actually happening. It's good to know you're still out there somewhere. Would the pivoting headshell have any effect to ameliorate the skating force? |
It may not be possible to eliminate the skating force, but after a couple of months' experience with the RS arm (not the headshell), you come to understand that -- laws of physics or not -- it simply doesn't matter.
I know, I know.
This was SONICALLY the finest arm I ever used. It got more music out of that groove than my JMW, SME and cherry wood tonearms. On the other hand, I found it an ergonomic nightmare. I always wondered whether the headshell alone would be the perfect compromise, but unfortunately I have no arm on which it can be used.
Bottom line: Enjoy the thing and ignore the anti-skating issue. Good luck, Dave |
I have the RS Labs arm, and it has no provision for anti-skating. Just another data point. |
It is not possible for the RS-3 to eliminate the skating force.
The skating force exists because the arm has a fixed pivot and the frictional reaction force from the stylus in the groove does not pass through that pivot point. SInce the RS-3 changes neither of these it cannot and does not eliminate skating force.
I wish someone would explain how this thing is meant to work, all the explanations I have seen defy the laws of physics. |
As far as I know, the whole rationale for the design of the RS3 is to eliminate the skating force. To the extent that there probably is some small amount of friction in the pivot point of the headshell, that may generate some skating force, but it ought to be very tiny, much too tiny to require you to use the AS mechanism of your tonearm. In considering my response, please take note of the qualifier: "as far as I know".
It's always wise to experiment for yourself; try it with and without anti-skate and determine which you like best. |
