VTA and HTA overhang

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

Audiofeil, I'm with you there. I don't personally adjust VTA for every record either, but I think it is important to know how different adjustments effect things. Especially when setting up a cartridge.

If you don't adjust VTA for different height records then make sure you set your alignment on a medium thickness record. Unless you mostly listen to 120 or 200 gram pressings. This is what I do.

All that said I can understand why someone might want to adjust VTA for different record heights. Most people don't have the time or patience to fiddle with it. Myself included.

Actusreus, The only way the offset would not move when adjusting VTA up or down is if the tonearm post was curved. Lets use your fork as an example. If you lift your fork without moving the front at all it will trace an arc in the air. Turn the fork on it's side and put it on a piece of paper. If you attached a pencil to the end and rotated it keeping the tongs centered, it will trace an arc. Unless the tonearm post can trace that same arc it will effect overhang when adjusted.

Peter, The people that try to get the perfect SRA for every record must believe that it's more important than perfect alignment. I doubt there are many people that would go to the trouble of adjusting overhang for every record as well.

I'm sure someone could design an arm with a curved VTA tower with on the fly adjustment. It probably would not be worth the effort as I imagine it would be quite difficult to accomplish. It would be allot of work for a little gain in accuracy.

Fleib, I can't really argue with what you're saying but what I mean by perfect alignment is least distortion. For pivoting arms this means least max and/or average distortion for horizontal alignment. Have a look at the alignment calculator on vinyl engine. If you play with the null points and or different alignment such as Stevenson or Baerwald it will show the maximum and average distortion for each choice. For least maximum distortion Baerwald is the way to go.

Can you hear it if it's a little off? I think so if your system is resolving enough.Is it a big difference? Not really.

Fleib, I'm not sure where I wrote that SRA does not matter. I don't feel that HTA is necessarily more important than SRA. It's all important and all we can do is optimize all the dimensions the best we can. I also do not think that small adjustment of VTA without resetting HTA is wrong. I was just pointing out its effect on HTA.

As for Stevenson or Baerwald you gotta go with what sounds best to you.

I just looked at the vinyl engine calculator again and it shows Baerwald as having the least max distortion and Lofgren B as having the most max distortion. Lofgren B has the least average distortion though. Baerwald has less max and average distortion than Stevenson so I can understand why it is popular.

Theo, The Herbies Way Exellent II Mat is what I think Tom is referring to. I have one and have used it on a LP12. They are fairly light and work well on the Linn. They do make them in many different heights.

On my current TT I prefer a harder mat though.

Fleib, I'm not confused. Yes Lofgren B has the least average distortion. But Lofgren B also has the most max distortion. Meaning that at the beginning and the end of the LP the distortion is higher than the other alignments but in the middle of the LP the distortion is lower than the other alignments. It's a compromise.

We are not really saying different things. We are just expressing it differently.

From what I've read the distortion gets higher towards the inner grooves because of the tighter radius. It seems to me that you want to minimize distortion at the end of the record. Lofgren B has the most distortion at the inner and outter grooves. I would think this should be avoided unless you are playing discs that have no music on the inner gooves. Like most of the newer 12" 45's I have gotten. I also have some double LP's that don't use much of the inner grooves either.

Ketchup, I was not aware of that feature on the ET arms. Very interesting.

Some say that the tracking error of linear arms is actually more than pivoted arms because of the higher horizontal effective mass. This causes the cantilever to deflect more than is optimal and creates tracking error.

I don't own a linear tracker so I have no personal experience with that. At the last RMAF I spoke with Peter Ledermann of Soundsmith. With his new Hyperion cartridge there is an option for a suspension optimized for linear trackers. Horizontal compliance is lowered while the vertical compliance stays the same. This stops the cantilever from deflecting too far. This in turn lowers distortion. This sounds like a good idea. I'm not sure if that option is available for his lower end carts though?