Question about Thorens 320MKII and Antiskating

[taotao]

Hello group,

I'm a bit confused about the right antiskating setting on my TT.
If I set it according to my bearing strength (?) 1,7Gr AT OC9, and put the needle on a plan surface; It always drifts to the inner point.
Now my question: Is this the right way to test antiskating, or is this method not usable? (I read controverse about it; some say yes, some say no :-}

Thanx

[sreten]

Hi,

As far as I'm concerned that method only sets the minimum anti-skate required. Indicated A-S on dials is often very wrong.

/sreten.

[Corax]

Anti-skating is the counter force to prevent the needle moving inwards based on the misangle between the tangent of the groove and the line from the centerpoint of the tone arm to the point the needle touches the groove. Unless you've no tangential tone arm (where you don't need that counter force at all) the force is not constant over the angel because the tone arm only hits the ideal carving curve angle (while the master was produced with a tangential driven stylus) twice while moving from the outside to the inside.

Actually the force is, with radial tone arms, always present and decreases with decreasing radius.

A good explanation is also given at http://de.wikipedia.org/wiki/Tonarm under chapter "Skating und Anti-Skating-Einrichtung" since you're a german fellow Taotao.

Unfortunately the skating force is also influenced by friction and other parameters and depends therefore in addition with the down-force of the needle.

So, my recommendation is to set first the down-force according to the datasheet of the needle and then (if provided - best case), for a starting point, a look-up in the (in most cases not provided) diagram or table which roughly states the necessary anti-skating force for a given needle down-force. To drop the needle on a plane surface and to figure out the best setup for the anti-skating I used a self made 'blank' record. To find the best material for making this 'record' you might have to experiment a little bit, because it shouldn't be too hard (to damage the needle) but on the other hand not too soft (to make grooves just by dropping the needle on the record ).

However, when this record is available I just put the needle down at approx. half way between start and endpoint of the groove (of a 12" of course) and see where it moves. Always keep your hands close to the tone arm to prevent any damage to the needle when it tries to move rapidly to either outer or inner edge.
(Re)Adjust the anti-skating knob/wheel or whatever you've on your turntable until the forces are equal and the needle doesn't indicate any tendency to move/accelerate in either direction (you won't really see that happen though).
The whole procedure might takes a couple of minutes and you'll never get the damn needle to stay at the angle where you put it on, but whenever you feel the force is at the weekest point you've done it and you can quit this needle torture.

[taotao]

thank you both. I like that blank disk idea, so I`ll give it a try.