Tonearm VTA adjustment

Precise adjustment of the Vertical Tracking of your tonearm is one of the most significant improvements you can make to your listening experience. It is not as difficult as you may be thinking, and costs nothing. You have already paid for your equipment, and though the turntable may have been set up “perfectly” at some time by a dealer, experience shows this is no guarantee that it is correctly and precisely adjusted right now. Parts move with use, and the tightness of fittings can alter over time.

In less than 15 minutes, the effect of adjusting, refining the adjustment, and eventually locating the “sweet spot” in VTA – just a turn of the adjuster, listen, turn a little more, listen, turn again until you finally locate it  – completely transformed the performance of the system. The stereo sound stage snapped into focus, the troubling bass lifted, harshness was replaced by sweetness, an extraordinary and unexpected experience.

VTA: The Technical Stuff, in pictures

(Note: these pictures are not the latest LJC kit, which continues to evolve)

The adjustment wheel on an Origin Live Encounter tonearm. Most good quality tonearms will have some sort of equivalent method of adjustment. It turns to raise or lower the tonearm, and holds a grub screw to tighten on the final position.

Vertical Tracking Angle Adjustment.

Achieving the correct angle by adjusting the height of the tonearm  is critical to achieving accurate groove tracking. Altering the arm height is carried out by rotating the helical screw disc up or down – which alters the angle that the stylus makes relative to the surface of the disc, and thus how well that line-contact stylus matches the ridges cut by the original lathe onto the groove wall.

The stylus will ride perfectly in the groove when the arm is perfectly horizontal and parallel to the record surface. Starting with a spirit level and rough-tuning up and down to achieve a fairly level tonearm position, it is then necessary to fine tune the adjustment to locate the very small range in which the “sweet spot” is found. In this case, trial and error found less than a quarter turn of the adjuster identified the huge step change in soundstage and tonal balance as it springs into or out of focus. You have to find that sweet spot!

An audio engineer talks numbers

Just in case you were thinking LJC was off his medication with this sweet spot business, an audio engineer walks you through the principles and metrics here, extract below:

Assuming the (VPI) tonearm to have a 300mm effective length, to get a one degree change of Stylus Rake Angle we need to alter arm height by 5.23mm. A 1.0mm change in arm height changes SRA by 0.19 degrees. The VPI’s VTA adjuster clicks equate to 0.35 thousandths of an inch according to Mr Gregory. That translates to less than one hundredth of a mm. He says that changes of +/-2 clicks produce a “vital” change in sound quality. So once you’ve found that sweet-spot a change of 0.018 mm (2×0.0091) will lose that perfect reproduction. Now just to drive that point home that 0.018 mm equates to a 0.00342 degree change in stylus rake: around  three thousandths of one degree!

Lessons learned

Very small adjustments create very large changes. There should be nothing surprising about that, though it was, as the whole business of hi fi is about massive amplification of microscopically tiny signals. A discernible change in pitch is created by movement in the vinyl wall one thousandth of the thickness of a human hair, detected by the styus sitting in the groove. The angle of the stylus tip determines how much of its surface area makes full contact with the groove wall. As they say, simples. Compare the sound.

There are audiophiles who in all seriousness say they can not hear any change resulting from VTA adjustment. For them, with their equipment, and their ears, that is the truth, I have no reason to doubt it.  My experience has been of massive change – my equipment, my ears. And I reckon it’s adjustment has been “off” for a very long time, I have no idea why. At the other extreme there are adjustment-addicts who say that you should adjust the VTA individually for every record, to account for changes in vinyl thickness. And they are probably right, though that way madness lies.

Benefits

The improvement in sound has been most noticeable for stereo records. The soundstage has really come alive, and the tonal range sweetly harmonious. That is very good news for the hundred Japanese pressings in the LJC collection.Already I am rediscovering and enjoying my Kings and Toshibas in a new way. So much so, I’ve ordered four more.

The other main benefit has been the significant reduction in vinyl surface noise since finding the VTA sweet spot. There is probably some science behind that too, but the effect is most welcome, whatever the explanation.