Nikola, I normally use a test record with tracks of increasing level, and listen with headphones, as that way I can hear better when there is mistracking. You have to hear the mistracking to know when it is equal on both channels. then re-adjust the VTF.
Having said all that, if, with whatever set-up, the sound feels solid and the image doesn't wander or get a bit watery, then fine. But I still feel more comfortable knowing that the forces on the stylus are equalized as best they can be, as the skating force is always there as long as you have a VTF
John |
Dear John, Thanks for the x time . 'As skating force is
always there...I feel comfortable that the forces on the stylus are equilized AS BEST THEY CAN BE'. You are of course refering to the fact that (anti)skate force is variable across the LP radius. To my knowledge only Sony
provided for a 'varible force' depending on the radius(?).
There are also some claims for the Triplanar (which I own) reg.
variable skate force but I can't see that, so to speak.
Is the variable anti-skate in this sense so difficult to design? The ususal 'solution' is just a (small)'hang'- weight.
Regards, |
Nikola A system like the Sony would be ideal especially if it was programable, such that the force could be adjusted to vary at different points - I don't know if this is possible. What is perhaps more interesting is that a mechanism of that kind might be used "in reverse" to measure the varying inward force trying to rotate the arm, and the settings stored for the next time the record is played. As you have steered the thread towards antiskate, can I recap and condense what I said in another thread? The skating force basically follows the tracking error curve of the arm (not the tracking distortion curve) which varies across the record. staying more or less constant within a few percent of around 25% VTF, reducing slightly during the first half of the side.
Depending on the overhang used and the arm effective length, at the inner null the force starts to increase rapidly. So it would appear that the ideal would be to follow this curve, reducing slightly then increasing.
However, it has been shown that there are other factors which increase the friction force as the radius decreases, which would skew this result and make it more likely that the force should at least be constant then increase, or even gradually increase all the way across the record. When I designed the RP1 that's what I did, as I thought that, like tracking distortion it seemed to be worse towards the inner grooves, and less of an issue further out, and should be weighted that way. My tonearms had an antiskate mechanism, using lever and thread, which allowed for varying the force, and the ratio to some extent across the record, or it could be removed completely. But it was not any more sophisticated than that - it was all "suck it and see". So, really, a tonearm should perhaps give the user the option of trying different things.
The actual amount of antiskate needed is very much dependent on stylus profile and downforce, as the skating force is proportional to VTF. Obviously, with enough downforce the stylus will never meet a modulation large enough for it to lose contact with the outside wall, or even throw it up out of the groove. However there will still be unequal forces on each side of the groove unless there is some kind of compensation. Does it exist as a force. It exists, yes, it definitely does. Whether its effects are noticeable to the listener is one thing, but why some people prefer no antiskate, or removal of the mechanism, that is for them to say. But the force is still there, and it has to be dealt with somehow. As Dertonarm says, a longer arm has less skating force than a shorter one. In that, we agree. So as I see it, the bottom line is that there is a turning force (a torque) which tries to rotate the arm inwards. This torque has the effect of reducing the VTF on the Right channel and increasing it on the Left. Without compensation, one channel has more VTF than the other. J . |
