VTA and HTA overhang

Certainly no offense taken, Theo.

Let me try to explain my point again. Here's my thinking: Imagine that the following three points form a triangle as viewed from the side. The first point is center of the arm tube intersecting the arm bearing point or line. The second point is the stylus tip. The third point is at the center of the arm tower at the plane of the record. Now imagine raising the VTA. Point #1 moves up. This pulls point #2, the stylus tip, slightly in toward point #3. An extremely short arm tube helps to illustrate the figure. The fact that the stylus tip moves relative to point #3 means that overhang changes as VTA changes.

If viewed from above, the stylus tip is now inside the original arc that the stylus traced across the LP. Or if it were possible to swing the arm all the way in toward the center of the LP, the stylus's relative location to the spindle changes as VTA changes. This is overhang, or Horizontal Tracking Angle (HTA).

I confirmed this effect tonight by observing the relationship between my stylus tip and the arc on my MINT LP protractor as I raised and lowered my VTA. When I increased (raised) VTA, my stylus tip moved inside the arc (more at the outer groove). When I decreased (lowered) VTA, my stylus tip moved outside the arc (again more at the outer grooves than at the inner grooves).

Now, I'm talking specifically about VTA. I recognize the importance of trying to match the SRA to the original cutting angle. Fremer recommends 92 as the closest compromise for the most LPs. I also understand that altering VTA effects SRA. I also agree that HTA which I think you refer to as Tracking Angle may not be as important as setting the correct SRA.

For the purposes of this discussion, I'm only looking at the relationship between VTA and HTA.

I'm just trying to make the point that as one adjusts VTA, overhang changes. This effects cartridge alignment and is quite audible. The closer my stylus is to the arc traced on my protractor, the more information my stylus extracts from the grooves and the less distortion there is.

Once the arm and cartridge are properly aligned, all should be fine. I'm just wondering what if anything those who adjust SRA by lifting or lowering their arms for each LP do to address the change in overhang which results from the change in VTA. I hope this clarifies my original post and like you, I'm just trying to learn something.

As one who has set-up hundreds and hundreds and hundreds of tables/arms/cartridges, I can attest to the fact that as you change VTA/SRA, it will also change the overhang.

As Peter states above, as the back of the arm goes up, the tip of the stylus moves in. As the back of the arm goes down, the tip of the stylus moves out.

That's why if you make a change in one, you must recheck the other. Just like VTF will affect VTA/SRA.

I agree with Peter that if a user is changing the VTA/SRA for each record, they should also check/change the overhang.

I've always kind of thought that the changes one hears by adjusting the VTA/SRA, might be due to the overhang change as much as the change to the VTA/SRA? Just my take...

Peterayer as it appears, I tried to edit my secon post to which you refer, and it vanished! But what I wanted to add is that I had omitted from my thoughts that you are working witha 12" arm whereas mine is a 9" arm. Those changes would be more dramatic in the geometric sense than I was thinking. I appreciate your response, although it may not make sense to anyone that hadn't read what I had said before as it is gone now. Maybe someone who has actually made these change and adjustments in compensation for each album thickness can enlighten us to their personal
experience. It will be interesting to read and learn although I for one will probably make some minor adjustments to my arm now that the SRA has been set to bring it to the sound I like and settle on it as a happy medium. But my arm is a Ekos and it isn't as accomadating for frequent adjustment. Someday if Graham ever does develop a proper spring for the LP12 to support at Phantom properly, I will look into that, budget permitting. So maybe it was a good thing my second post vanished as I was in error. But thank you for your reply and the explaination. By the way you didn't mention what arm you are using, just to satisfy curiousity at this point.

Peterayer,

I don't quite understand your triangle illustration, but you seem to be making an assertion that as you move the arm up or down, you pull the stylus in or out. I just don't think this is correct. Perhaps large VTA adjustments might result in stylus displacement, but I just don't see why small changes in VTA should result in overhang changes. The simplest illustration I can think of is lifting a fork that is placed teeth down on a flat surface. You can certainly move the back of the fork up and down without bringing the teeth on or out; you only change the angle at which the teeth and the surface interface.

If you were correct, any tonearm designer who offers VTA adjustment on the fly would not understand the basics of cartridge alignment, which is absurd. My guess is you're doing something else to the alignment as you adjust the VTA that would explain the overhang changes you noticed.

Theo, You can refer to my system page. I have an SME 12" arm. As such, it requires a greater increase or decrease in VTA to effect the SRA than it would with a 9" arm. Similarly, the offset angle at the headshell is less than with a shorter arm, so skating force is not as great. Also, SRA changes during warped records are not as great.

Actusreus, I believe you are mistaken. As mofimadness pointed out above, changes in VTF, even very slight, do change overhang and thus alignment as the effective length of the system (pivot point to stylus) is altered as the cantilever changes angle due to the greater or lesser tracking force. Your fork analogy is a good one. As you raise the end of the fork the teeth will indeed move in or out. Remember, your lifting hand must move vertically only. Imagine a very short fork and movement up or down of one inch.

Even though a small VTA adjustment only changes overhang very slightly, and it may not be audible to all, overhang does indeed change, changing cartridge alignment. I believe this is a geometric fact.

I'd like to hear from those who change VTA for different LPs if and how they account for the change in overhang. Mofinmadness understands the issue. I'm trying to learn if it is more theoretical than practical.