VTA adjustment for VPI 10.5 tonearm


I am trying to get the VTA adjustment right on my reference superscoutmaster signature/10.5/koetsu rosewood signature platinum combo and right now classic records 200g and 180g set at "85" position seem right with a slight boominess in the bass. With thinner records (140-150g), it seems I need to lower it to around the "50" position in order to not have a graininess in the sound. Is my thinking correct or is there some other adjustment like adjusting the gain (I am using 30ohm load on my pass labs xono phonostage)? Any input would be appreciated. Also, how do I know the correct distance to keep the rim drive from the platter and should it be in the silver ridge or should I adjust the minifeet to have the rim sitting on the black part of the platter?
powerdoctor

Showing 2 responses by sonofjim

I agree with Stringreen. Set VTF first and do that with the arm as close to level as possible. The index card trick makes it easier to judge this with the taperred arm. Depending on what scale you use, you'll likely have to raise the arm for this measurement to have the arm level. I f you don't have the arm level, your VTF reading could be off by as much as .3 grams or more. This is the equivalent of measuring VTF at the level of the record(as the expensive Wally scale does)provided you then set the arm level with the record again when you're done. Once the arm is level with the record, lower VTA by 5 at a time until you find the spot you like.
Stringreen is probably right about the soft feet and anti scate as well but I'm still messing around with those on my SSM ref. The rim drive seems to work best with very light conact with the super platter. Not much pressure is needed. Mike at VPI told me if the platter spins a little longer than the flywheel on shut off that's about the right amount of contact. Also, where the platter runs the fastest is another indication that contact pressure is good. The drive belt does need to be in the "land" between the grooves in the metal area and probably best as close to the middle of this metal area as possible. Luckily, raising and leveling is easier with the mini feet than the older cone feet. Probably the mini foot's best selling point in my opinion.
Stringreen,
When running your table without the anti-scate do you use the wire twist or just nothing? I know in the past you have felt that the wire will fatigue and the twist will loose it's effectiveness. I'm still trying to talk myself out of the anti-scate off and on but currently am still using it at about as light a weight as it will operate without the lever falling over as the stylus reaches the center of the disc.