VTF, VTA, SRA, and 92 degrees - question

The difficulty with VTA is that it is the angle between the record, and a line joining the tip of the stylus with the fulcrum...wherever that is. It is not the same as the "cantilever angle"! It is usually about 2 degrees more than the cantilever angle, depending on the length of the cantilever and height of the diamond. It seems that no cartridge has the "gold standard" setup (VTA 20 and SRA 92), they all seem to be out, often by quite a large margin. So I'm not sure what to do about this. Mine sounds brilliant with the tone arm near horizontal, which gives a cantilever angle of 22 degrees and an SRA of about 95 degrees, to correct the angles I would have to drop the tonearm base by about 15mm, and I'm sure the mechanical problems associated would make things worse (on an 11 inch arm 1 degree change in SRA equates to over 5mm change in arm height!!). I think the jury is still out on this one, perhaps the best is to set by ear from horizontal. I suppose I'm as confused as most everyone else:)

Well, with all the measuring tools, calibrated blocks, and digital photos I have I think (!) I can get back to where I am now. I'm going to try again by starting with the cart at horizontal and see what happens from there.

Tony, can you hear any difference between 1 degree changes?

Dinster, you could try putting a 2mm shim on the back of the cartridge between the headshell and cart. This will angle the back of the cart down and get you much closer to 92 degrees. I have a little brass shim for this purpose and it works well. I have a cart that needs this shim in the front because I can't raise the back of the arm high enough without it.

I am sure some of you have noticed that different records seem to need a slightly different VTA. The reason for this is two-fold; first the LP is a different thickness. The second is the the cutter stylus on the cutterhead that cut the lacquer for the LP may have been set at a slightly different angle. This is why two LPs of the same thickness on the same label may still need to have two different settings.

The cutter stylus has the job of cutting the lacquer. To do this it is shaped a certain way, heated to a particular temperature, set to a particular angle (cutter height) and tracked at a certain pressure. What works on one day in the mastering lab may not work the second day as the lacquer can be different, even if only by temperature (they cut easier on warmer days for example). So the mastering engineer has to be constantly aware of the condition of the stylus and keeping test lacquers on on hand to get immediate feedback on the effectiveness of his settings.

So this may not be as exact a science as you all might be thinking- it is as much an art. The 92 degree value is an excellent approximation, just as is getting the front of the cartridge to be perfectly perpendicular to the LP surface. This is why it is helpful to be able to adjust the VTA on the fly, like you can do with the Triplanar tonearm.