Stylus Rake Angle

John, Thanks for the treatise. I agree with your definitions of the terms, but I cannot see the point of your statement:

"Now while the stylus might be set at 92 degrees, the cantilever may not be at the same angle as the the cutter."

The cartridge is a transducer whose optimal function depends upon a fixed spatial relationship between the magnets and coils, as one or the other vibrates. Once the LP is cut, why should the cantilever give a damn about the cutter angle? The stylus "cares" about that in terms of SRA. So I would think that you set VTA so as to obtain proper or optimal SRA, first of all to assure proper energy transfer between groove and stylus, and then it is VTF that mainly assures the proper spatial relations between the transducing parts of the cartridge. VTA is just a convenient surrogate for SRA. Probably this has become a discussion about semantics.

John, semantics aside, if you are correct, then why are we discussing SRA? If the cartridge manufacturers want to refer to SRA as VTA and vice-versa, so what? All they are doing is referencing a record manufacturing standard. There is no way VTA refers to cantilever/surface angle. I've owned many cartridges and I stand by my statement on that. My goodness, I've had cantilevers that are curved!

Csontos,

If the cartridge manufacturers want to refer to SRA as VTA and vice-versa, so what?

They can call it what they wish, as can you, but the terms are distinct, and in adjusting every cartridge varying one varies the other.
VTA in a cartridge should be the same as the equivalent angle in a cutting lathe.
SRA should be the same as the cutting stylus angle.
My point is simply that optimising one does not automatically mean that the other is also optimised. This was the argument for using SRA rather than VTA to set up in the first place.

I used the cantilever angle as a easily understood approximation of VTA. The actual angle is that between a line drawn from the cantilever pivot point to the stylus tip and the record surface. For most cartridges this is close.

Lewm

Once the LP is cut, why should the cantilever give a damn about the cutter angle? The stylus "cares" about that in terms of SRA. So I would think that you set VTA so as to obtain proper or optimal SRA

The reason there is such a thing as VTA is that the stylus moves through an arc which is described by a radius the length of which is approximated by the cantilever and ostensibly at 20 degrees +/- 5, to the record surface. The reason for that is that the record was cut in a similar manner, the cutting stylus (while set at, say, 92 degrees to the lacquer surface), also describing an arc, as it is constrained within the cutting head. Variations in VTA cause distortions. They may be less of an issue than SRA but do exist.

But doesn't VTA become a moot point when matching SRA to whatever it is, by ear? VTA is static and fixed whether it's accurate or not. The angle of the stylus relative to the cantilever is not a fixed standard. I don't understand why you keep referring to the cantilever. If you insist that I refer to SRA as VTA, fine. It seems to be a matter of communication. Could you please explain to me the correlation between SRA and VTA?

I think what John is trying to explain is that the arc of the stylus as it moves from side to side will be slightly different if the angle of the cantilever does not match that of the cutter. Irregardless of the SRA of the stylus/cutter.

I've never seen a LP cutting lathe up close. Does the cutter have a cantilever and suspension just like a cartridge?