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Ancient AR Turntable with NO anti skate

A friend had me over to listen to his restored late 60's Acoustic Research turntable.  While listening, I noticed that the somewhat awkward looking tonearm had no anti skate.  Looking closely at the stylus assembly, it wasn't drifting or pulling toward the center spindle.  It seemed to track clean and true through the entire LP.  The arm is the original stock AR arm and couldn't be more that 8.5" or 9" in length.  I am just curious how AR pulls that off with such a short arm?  I have seen several 12" arms (Audio Technica for example) that dispense with anti skate completely but never a smaller one.  By the way, the table sounded wonderful and the cartridge was a Denon 103R.

Thanks,

Norman

 
normansizemore

Showing 5 responses by rotarius

rotarius
431 posts
 
Hello norman, I don't see why one would not apply the antiskate bias if this feature is available.  The skating force exists for every pivoting arm used with any stylus.  It is a vector quantity, very real, not some alternative fact.
rotarius
431 posts
 
Well, you could purposely not level the TT such that the tonearm drifts in the outward direction when zero balancing the arm.  That can help get by without a bias mechanism.  If everything is correctly set-up and the tonearm bearings don't produce a drag, I have always found a channel imbalance without a bias force.
rotarius
431 posts
 
And that is why designers use a spring or magnet for antiskate in many of the tonearms.  It is to vary the amount of the bias force as the arm gets closer to the spindle.  Saying we don't provide an antiskate mechanism because the skating force changes over the record is silly, IMO.
rotarius
431 posts
 
The skating force is a component of the friction force vector so it is dependent on the tracking force and the offset angle.  Friction in turn is also dependent on the groove surface, contact area of the stylus, etc.  Back in the day, some manufacturers would provide a chart of antiskate values based on the stylus profile. Most vintage tt antiskate dials were calibrated for conical stylii, you have to dial it down a bit for ellipticals.
rotarius
431 posts
 
Norman, your final check/adjustment should be with mono LP to make sure you have even output from both channels and music is coming from the central region between speakers.  Assuming that your room acoustics don't produce an uneven balance to begin with of course.
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