Another Angle on the "Digital Can of Worms"

To continue the discussion of whether or not using a USB microscope to set stylus rake angle is a good or bad idea, please look at the drawing accompanying this post.

In the drawing, you can see the visible front shank facet. This drawing duplicates the angles produced in one used on the website claiming using a USB microscope will not produce useful results, which we will not disclose here.

We're not using the actual image on that site, but this one, created by Wally Malewicz duplicates the off-axis angle in that website's image.

Note that to produce such an error ( a measurement that's off by 3 degrees) requires the digital microscope's central axis to be off by more than 6 degrees—an amount that's easy to see and just as easy to correct.

As Wally pointed out to me in an email, if you view an analog speedometer from the passenger seat you'll get a similar parallax error and the wrong speed. Does that mean you shouldn't use a speedometer to gauge speed when you drive? Well, no! Unless, of course, you are in the passenger seat!

AndyPrice44's picture

Nice illustration and explanaition. I personally will continue to use the microscope to set the SRA. I don't see how using an instument that allows you to clearly see what you are doing can be a bad thing.

Zardoz's picture

You want to finish by listening anyway don't you. I mean you can't just set it by what you see and assume all is ok. Right?

Michael Fremer's picture

Yes, absolutely finish by listening! However, if it sounds great and your arm does not allow for easily repeatable settings (such as ones with just a post and a grub screw) leave it alone!

wheatie's picture

Thoroughly agree that ultimate test is does it sound better. Answer in my case - significantly.

Jim Tavegia's picture

It is clear that not having everything lined up and perpendicular is going to cause problems. It is clear now that deviations in the tonearm tube being able to hold the cart square is an issue among other things.

I'm wondering if most of us would be able to get our tables, the microscope and the cart body with the platter in the same plane with the needed kind of accuracy you  are talking about with any table under $1K?  It still does not mean we shouldn't try I would think. 

detroitvinylrob's picture

Like most things in life, some may be missing the forest for the trees... We can knit-pick the details of position of stylus to that of say the cutter head or whatever, we can quibble about USB microscopes and their proper set-up (I concede that the details are important) but, in the end isn't CLOSER (by any degree) BETTER?

I think the efforts to inform, educate, and create dialog by Mikey and Wally and the  affordability and availability of a USB microscope will dramatically change the quality of our listening for the better (and possibly, the undo wear and tear of our beloved Vinyl and expensive cartridges) not to mention that a closer consumer eye on stylus build tolerance is not a bad thing.

Obviously, listening is the final test, it is the final act and purpose of all this tweekery, but in my view, lets not fool our selves in thinking that getting as optically and measurably close as possible is some how not the "first step" or that swagging it in by ear alone will give you the same or even consistent results.

I commend the hard work of these fellows and what they bring to our fair hobby. After all these years of being a Vinylphile, living to see the rebirth of Vinyl, and now to enjoy this increased audible performance and improved understanding just leaves me happy and grateful to be part of it all, thanks Mikey.

So much Vinyl, so little time!

Happy Listener!

rlw3's picture

i have a graham 2.2/ koetsu rosewood sig  which can be raised and lowered. when doing so to listen for a sweetspot:

is is better technique to raise the back of the arm or lower it as you listen for differences?

given the hash marks on the graham vta tower do you try to move a quarter of a hashmark at a time? more or less??

how big is the sweetspot compared to the distance between hash marks?

glad i still have lots of work to do getting this perfect and having nothing to fiddle with would be boring.

thanks ray