VTA and HTA overhang

Theo, I think you are referring to an SRA of 92 degrees. I have met MF and listened to him discuss this topic and it makes sense to me and I have viewed my stylus through a USB microscope and tried to calculate the angle. I do my final adjustment my ear.

My point is that I was surprise by how much the overhang changed when I adjusted my VTA/SRA by lifting the back of my arm. I have settled on one height and corresponding SRA angle and leave it at that. I don't plan to adjust my VTA for each LP.

My questions is really for all of those analog guys who purport to adjust THEIR VTA depending on which LP they have spinning on their platters. I am wondering if when they raise or lower their VTA (on the Graham, Tri Planar, Durand, whichever arm makes this easy) they are taking into account the resulting change in HTA or overhang. The cartridge's alignment changes with changes in VTA and I'm not aware of audiophiles realigning their cartridges with each change in VTA, that is with each LP.

Thanks for the suggestion to contact Rick, but I'm all set with alignment and settings.

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.

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.

Sarcher, you are absolutely correct that raising or lowering the VTA the same amount as the LP thickness difference will preserve the original alignment. There, I knew I would learn something and this is so obvious.

However, some of the people I know change SRA for different records by listening and trying to duplicate the original cutting angle. This is independent of record thickness as there is/was no standard cutting angle, though most I guess were around 92 degrees. For these people, changing SRA does indeed alter alignment. Perhaps to such a small degree that it is not an issue.

And as Audiofiel wrote, life is too short. I set SRA with a 150-160g LP and leave it, obsessing no more. However, I do spend 20 minutes per side cleaning an LP, because it sounds better to me, so we make our choices, even if they are inconsistent.