Dumb VTA Question


Sorry ... I have a dumb question about setting VTA. I own a VPI Classic TT which has "VTA on-the-fly" capability. My cartridge is the Lyra Kleos. When I mount the Kleos, the last adjustment is VTA. I start by setting VTA so that the tonearm appears horizontal. Then while I'm playing a record, I raise the tonearm and then lower it until I like what I hear.

Ok ... that's what I do. But here's the dumb question. Some vinyl buffs talk about setting VTA at 91.5 degrees, or 92.5 degrees, and the like. How the heck can someone know the degree of VTA adjustment with such precision?? Is there a tool or special protractor that permits such close adjustments?

Thanks for the education.

BIF
bifwynne
Bruce, you will note that in the first photo of the analogplanet link that Mofi posted, Mikey is also using the digital microscope to set up a Lyra Kleos cartridge, just like yours.

Great links Mofi!

Cheers,
John
Thanks guys, esepcially for the terminology lesson. I always thought that VTA and SRA are flip sides of the same adjustment. That is, VTA and SRA change as a result of raising or lowering the tonearm.

Jonathan, I can visualize that raising the tonearm geometrically changes the effective length of the tomearm. And, the VTF force vector will correlatively change as well. However, I find that these variables change only slightly. Maybe it's because my tonearm is 10.5 inches long.

In my earlier days of vinyl OCD, I actually remeasured alignment, VTF and even azimuth after changing VTA/SRA. The changes were very, very slight. Too much OCD for me now to mess with it. But ... I am able to detect changes in the acoustic presentation when I raise/lower the tonearm.

So, as I mentioned above, I start out by setting the arm to be horizontal/level based on an eyeball look-see. Then I raise/lower the arm until it subjectively sounds best to me.

I'll check out the links provided. Thanks for that information.

That leaves me with a question or two though, perhaps best addressed by Jonathan Carr. Could my methodology damage my "beloved" Kleos cartridge/stylus or my LPs? Relatedly, is my "eyeball" method resulting in degraded sonics, qualitatively speaking? Is it worth investing in a USB digital microspope?

Thanks again guys!!

Bruce

P.S. -- Jonathan, would you kindly repeat your advice about sending my Kleos cartridge back to Lyra for an inspection and adjustment (if needed). I'd like to have it checked to ensure that it is operating within spec.
J Carr's comments are spot on. If you look at the original paper Michael Fremer cites re: SRA, it is not an exact measurement; rather it indicates a range. You are correct in assuming that it is difficult to measure SRA with precision and accuracy. Dave Slage has pointed out how small parallax effects can significantly influence SRA measurements and reproducibility. Fortunately, we are not listening to a measurement. By all means, if measuring gives you a degree of confidence that you are in the ballpark of optimal set up; get out your computer and USB microscope and measure away. Ultimately, your ear will be the best guide for SRA/VTA parameters. And don't forget to recheck all other set up parameters once you've got SRA/VTA spot on. Yes, it's an iterative process that may require mutliple listening sessions.
Dear Bruce: I've used 10.5 inch (and longer) tonearms, and my experience was that the VTF and overhang errors introduced by SRA changes were significant enough that correcting the VTF and overhang did alter the sound. The real PITA is that you need to repeat the cycle a few times in a series of gradually diminishing spirals before you can be reasonably confident that you have accounted for all variables, but that can't be avoided.

If you go to Stereophile's website, you will be able to find Mikey's review of the Etna. In the Manufacturer's Comments, I have added a wee bit about SRA in general, which I think you will find worth reading.

Ultimately you listen with your ears rather than your eyes. The visual method is simply intended to get you into putting range quickly, but you will still need to do the final tweaking by trial and error and ear.

Regarding possible cartridge damage... There was one dealer who thought that he wasn't able to lower the back of his Kleos sufficiently, so he ripped off the protective washi cover to give himself extra room. Please don't ape this (smile).

I recommend that you get in touch with Alasdair Patrick at Audioquest, and have him tell you when and where to send in the Kleos. Please stick a memo on the outside of the box to the effect that you don't think that there is anything outright wrong with the cartridge, but in consideration of how long you have used it (provide purchase date, please) that you would like to have it inspected for wear, suspension ride height and alignment.

At the time that you send the Kleos to Audioquest, you could also email me the cartridge serial number and perhaps a slightly more fleshed-out version of the memo that you attached to the outside of the box.

kind regards, jonathan
Thanks J Carr!! :)

I will be sad until I get my Kleos back. :( :(