Do You Have a Favorite Disk to Set VTA/SRA?

Interesting pictures of stylus shapes.

http://www.vinylengine.com/turntable_forum/viewtopic.php?t=22894

Chayro, great link, thanks! The pics/diagrams help explain what I was attempting to describe.

During the cutting process, the cutting needle lasts about 10 hours and then must be replaced. A worn needle cuts a noisy groove. Many people don't know this but if the cutter needle is set up right, the resulting lacquer cut is so quiet that no matter how quiet your playback electronics are, they define the noise floor.

As a result the cutter head must be removed and the needle replaced fairly frequently. Then it has to be reinstalled, aligned and then one goes through the process of getting it to cut correctly. This is the case regardless of the fact that the settings of the cutter head were previously recorded.

The issue is that every cutting stylus is slightly different. As a result, the 92 degree cutting angle can be regarded as an average and not an absolute as the mastering engineer is looking to get the machine to cut properly and is not aiming for 92 degrees. This means that every LP is cut at a slightly different angle. IOW its not just the thickness of the LP that is a variable. Even if they were all the same thickness to get ideal playback the VTA/SRA would have to be adjusted.

Hence the utility of the VTA tower pioneered by Triplanar. There are several arms now that use a similar design; if you really want to hear everything on the LP such adjust-ability is really handy!

Ralph,

Thanks for your expert insights from the POV of a cutting engineer, which do gibe with what I hear during playback.

Similar weight LPs from the same label and pressing plant do tend to have similar arm height settings, but it's only a tendency, a reasonable point of departure to begin fine tuning by ear.

I've always found the obsession with setting SRA to EXACTLY 92 degrees with a microscope amusingly arbitrary. You explained why that is so very clearly.

So - Wouldn't the average audiophile's life be easier with a spherical stylus? Just set the overhang and a reasonably parallel arm tube and you're pretty much done. I wonder how compromised the sound would be if a high-quality spherical stylus were put on a good cartridge, say $1500-$2500. This is of course for those not willing or able to achieve perfect alignment and reset VTA for each record. I haven't done a survey, but I think sphericals are used on lower-priced carts to keep the price low, but why not on a better cart? What do you think, Doug?