Dumb VTA Question

Bif...you're talking about SRA, not VTA. SRA is "stylus Rake Angle", VTA is "vertical tracking angle".

http://www.vinylzone.com/cartalign.asp

Most users are using a USB digital microscope to set this up.

http://www.analogplanet.com/content/how-use-usb-digital-microscope-set-92-degree-stylus-rake-angle-sra

Dear Bruce: The SRA monitoring procedure is as Mofimadness stated.

However, as I recently wrote in Stereophile, the construction of every tonearm that I am aware of (with the sole exception of the Eminent Technology linear trackers) guarantees that altering SRA will simultaneously cause the effective length to change, along with the tracking force.

To make sure that any SRA-induced audible changes are truly attributable to SRA rather than sundry alignment shifts that came along for the ride, you must recheck the overhang and tracking force and "put them back" to what they were prior to the VTA change.

At the end of the day, you may ponder about the real value of "VTA on-the-fly" mechanisms (grin).

kind regards, jonathan

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.