VTA and HTA overhang

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.

Good topic Peter. I have noticed this effect as well.

Actusreus, your fork analogy does not work. If you could lift the rear of the fork straight up without letting it move forward as you lift it would pull the front back. This is quite easy to test with your tonearm. Just setup your alignment protractor and play with VTA. It's easy to see.

Now as long as you only make small changes in VTA it may not be necessary to reset your alignment. It depends on how anal you want to be.

When setting up a cartridge I rough in the weight first then rough in the SRA. That way when you set the alignment it won't change as much when you dial in VTF and VTA. It does make sense to readjust overhang as a last step. If you change VTF and/or VTA significantly afterward you should also reset overhang. Most people don't take that into account though.

Sean

Peter, What happens when you use a taller record than the one you used to set your alignment? A taller record will push the stylus forward a bit. By adjusting VTA up the correct amount you compensate for that. So adjusting VTA for different height records preserves the correct overhang as long as you adjust it the correct amount.

Sounds like you just made a case for VTA adjustment not against it. ;0)

Unfortunately there is no way to account for record warps as they will surely change overhang as well. Even clamping and or vacuum hold down will not remove all the warps.

Sean

I'd rather listen to music and compromise on "ideal playback" than adjust my tonearms for every record.

Life's too short IMO.

Sarcher30

Actusreus, your fork analogy does not work. If you could lift the rear of the fork straight up without letting it move forward as you lift it would pull the front back. This is quite easy to test with your tonearm. Just setup your alignment protractor and play with VTA. It's easy to see.

Sean and Peter,
Remember that you're not actually moving the tonearm, but the VTA tower or essentially the column that is supporting the tonearm. So in my fork example, if you threaded the back of the fork and inserted a screw that would allow only vertical motion, you could move the back of the fork without pulling it in or out.

I will adjust the VTA today on my table just of out curiosity. I know Doug adjusts the VTA for each record so it'd be interesting to hear his opinion on the matter.