VPI Tonearm VTA Adjustment

[MAXPWR]

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

 

[jgfergus]

On my VPI Aries with a JMW 10 arm, turning the VTA knob clockwise, lowers the arm, and turning it counter-clockwise raises the arm which is what my user manual states. The opposite of what you state.

 

[MAXPWR]

Hello jgfergus,

You are correct! See the corrected PDF File below. I was going from memory late at night....see where that got me

Correction: Adjusting the knob Clockwise lowers the tonearm Down and Counterclockwise raises the tonearm UP.

Thanks big time for catching this! I hope you find it useful.

 

[jgfergus]

No worries MAXPWR. Thanks for the pdf file. I have printed it and will find it very helpful.

Cheers!

 

[edwyun]

Good info. Thanks. One other thing to note is that the VTA tower as some slop in the dial. So you need to account for this when turning in or turning out. Also, when raising the arm, there is no problem. But when lower the arm, I have to place some weight (finger will do) on the top of the VTA tower to get the assembly to lower gradually. Otherwise, it will slam down.

 

[MAXPWR]

Good info. Thanks. One other thing to note is that the VTA tower as some slop in the dial. So you need to account for this when turning in or turning out. Also, when raising the arm, there is no problem. But when lower the arm, I have to place some weight (finger will do) on the top of the VTA tower to get the assembly to lower gradually. Otherwise, it will slam down.

Thanks edwyun, I have incorporated your comments in the REV C version of the VTA PDF document, which is attached.

 

[Audiotom]

I have a few comments to add for those who have very fine tuning vta towers

I have a Durand Tulea MK II tonearm on a Galibier Gavia table with a ZYX Universe Optimum cartridge
The cartridge is incredibly sensitive to vta.

My local guru Richard Gray and I came up with a solution.
Just eye sighting the digits on the tower had too much slop.

We ended up using a precise dial indicator (like they use in machinist shops)
and a NOGa indicator precision arm to hold it perfectly in place.

RIchard set the 120 gm Shure test record at zero - set the azimuth and antiskating
and calibrated 140, 180, 200 gm pressings

I also bought a fine caliper to measure lps directly
but most I can just eyeball very closely to their pristine setting

You can dial in the vta to 0.001 of an inch

the range of thicknesses is roughly 0.06 inches.

Of course taking that further on the fly by ear is simple and I don’t have to go to any excruciating adjustments

A $200 investment for those whose cartridge vta is very sensitive and who have tonearms with very fine vta adjustments - this is money well invested.

 

[PeterA]

Tom, do you have any photos of the device on your arm?

 

[Don C]

If you fine tune by ear, I find with my ZYX Airy 3, the sweet spot is within 2 index marks on the VPI arm, with any record.

It is not my experience that the widow between sweet spots going from a 150 gm record to a 180 gm record is as wide as 1.7 turns.

More like 7 to 10 index marks.

Your method does not match up with my experience at all.