The following information along with the attached PDF chart will allow quick and easy VTA adjustment on VPI tonearms using the VPI JMW Tonearm Base.
Typical record thickness range from 0.8 mm to 2.3 mm (0.0315 inches to .0906 inches). For total Delta thickness of approximately 0.060”. The associated weight range for this range of record thickness is 90 to 220 grams. An example of a 220 gram record is the Ultimate Analog Test LP, which is a common tonearm setup test aid.
The VPI JMW Tonearm Base’s VTA control knob changes the height approximately 0.035” per full turn (0.889 mm). To accommodate the 0.060” variance in record thickness requires a 1.713 turns of the VTA knob (+/- 0.86 turns of the knob if centered on an average 0.061” thick record, which would weigh approximately 155 grams).
If we optimize the VTA for a given record thickness we can quickly get a good “Course VTA Setting” by using the attached chart for other records. Just write down the VTA tower’s gradation mark next to the associated record thickness/weight on the chart for the record you have optimized the VTA setting. You can then fill in the rest of the expected “Course VTA Settings” for the other record thicknesses/weights knowing that each VTA tower mark is 0.00035” change and between the numbered markings 0.0035”). We now have VTA setting information that will cover the widest range of record thicknesses that we will ever encounter.
The easiest way for most people to use this chart will be to use a postal scale to measure the weight of the record in grams. Then look at the filled in chart to set the VTA tower to the predetermined setting on the filled in Course VTA Setting chart closest to the record weight we have measured. The optimum VTA setting for each record will be within a few VTA tower gradation marks. For the majority of us the Course VTA Setting will be very good and will have no need to go further in adjustment.
Note: Adjusting the knob Clockwise raises the tonearm Up and Counterclockwise lowers the tonearm Down.
The record weight and thickness information based on the following link and my own measurement of the Ultimate Analog Test LP.
https://www.vinylengine.com/turntable_forum/viewtopic.php?t=93648
Enjoy
Typical record thickness range from 0.8 mm to 2.3 mm (0.0315 inches to .0906 inches). For total Delta thickness of approximately 0.060”. The associated weight range for this range of record thickness is 90 to 220 grams. An example of a 220 gram record is the Ultimate Analog Test LP, which is a common tonearm setup test aid.
The VPI JMW Tonearm Base’s VTA control knob changes the height approximately 0.035” per full turn (0.889 mm). To accommodate the 0.060” variance in record thickness requires a 1.713 turns of the VTA knob (+/- 0.86 turns of the knob if centered on an average 0.061” thick record, which would weigh approximately 155 grams).
If we optimize the VTA for a given record thickness we can quickly get a good “Course VTA Setting” by using the attached chart for other records. Just write down the VTA tower’s gradation mark next to the associated record thickness/weight on the chart for the record you have optimized the VTA setting. You can then fill in the rest of the expected “Course VTA Settings” for the other record thicknesses/weights knowing that each VTA tower mark is 0.00035” change and between the numbered markings 0.0035”). We now have VTA setting information that will cover the widest range of record thicknesses that we will ever encounter.
The easiest way for most people to use this chart will be to use a postal scale to measure the weight of the record in grams. Then look at the filled in chart to set the VTA tower to the predetermined setting on the filled in Course VTA Setting chart closest to the record weight we have measured. The optimum VTA setting for each record will be within a few VTA tower gradation marks. For the majority of us the Course VTA Setting will be very good and will have no need to go further in adjustment.
Note: Adjusting the knob Clockwise raises the tonearm Up and Counterclockwise lowers the tonearm Down.
The record weight and thickness information based on the following link and my own measurement of the Ultimate Analog Test LP.
https://www.vinylengine.com/turntable_forum/viewtopic.php?t=93648
Enjoy