More on VPI Anti-Skate

MJGLO, did you notice that the anti-skating device can be set a number of ways. When the mechanism is adjusted so that the weighted arm that provides the reactive force is at its outmost point, the force is at its maximum. Very little outward pressure is exerted when that arm is low or high in its travels, since the weight is carried by the pivot. This maximum can be adjusted so that it occurs at the beginning, middle, end, or anywhere in between...with lesser pull at the intermittent points.

Stringreen,
I have the loop at the top of the upright arm for the most leverage and least movement. I have the line length set so at the start of the album the outboard arm is at the 8:00 position, at the end of the album it is at the 9:00 position. This is very little movement and very little change of force between start and end of the album, I'm not sure it's even measurable with any tools I have. Side note, I only use one o-ring to support the loop in the line from underneath and no o-rings on the outboard arm.

Mike

Stringreen,

Great thread. Hope the new home is all you hoped.

Your results map closely to our experiences using a TriPlanar/UNIverse and Cello's Graham 2.2/UNIverse.

As SirSpeedy first reported and we heard, the Graham unipivots also benefit from very fine, cartridge-specific adjustment of damping fluid around the bearing. It makes perfect sense that a JMW would do the same.

Most TP owners who hang around here have followed my suggestion to ditch the supplied metal AS weight in favor of something much lighter, to apply a very small amount of AS. We use O-rings and I believe VPI started offering O-rings with their AS option shortly after I mentioned that trick here. I should have patented that! ;-)

Without the anti-skate, his voice was centered in 3 dimensions exactly between the 2 speakers. I sensed a kind of blurring with A/S that was cleaning up without it... I suspect that although the A/S gizmo does its job as intended, it also provides a bit of damping to the stylus which simply may be too much in my system. This would explain the improvement using it with the arm not damped.

Exactly right, and easy to understand when you think about it. Just as with VTF, AS applies a constant external force to the stylus/cantilever. This presses the cantilever against the elastic suspension within the cartridge, which of course dampens transient response, limits dynamic extensions and smothers HF's. Just as with VTF, excess AS smothers and dulls the sound. Imaging loses precision because you've lost HF's, which our ears are most sensitive too when determining the direction, size and shape of a sound source. Images restricted to the lower frequency sounds from a source will always sound larger and more diffuse than images which include the higher frequency components.

Great observation picking up the relationship between well damping on a unipivot and AS. I suspect a similar relationship might exist with VTF. Sharing stuff like this is what makes this forum so valuable.

Best,
Doug

Thanks Dougdeacon.. It is wonderful here in North Scottsdale...only one problem.. I have yet to get the acoustics fine tuned in my new sound room (15x24 ft with 12 ft ceilings). I'm working on it though and every day brings me closer.