USB microscope for SRA - does this look right?

I finally stopped being lazy and picked up a USB microscope to measure the SRA of my EMT JSD6 cartridge. I'm not sure I'm placing the vertical line in the correct place, does this look about right? Stylus shape is a super fineline.

 

Not good. Good for a conical needle, but for elliptical, fineline, shibata etc the benefits only when the angle is excact like records was cutted.
Otherwise the needle doesn't track the high frequencies at all. So to see it looks like the diamond is fitted a bit too the front at a wrong angle.
But you can only be shure if you could look at the way the side lines are at the tip, photo not resolving enough.

 

nice work! i think your line is very close. but the SRA is off. The "holy grail" SRA is 92 degrees.
if you can raise the tail of your tonearm high enough to get to 92 degrees you could be in for a treat.
you may not have enough travel in your arm to raise it high enough, 88 degrees is very low. you might want to check your VTF is not too high. you also might have a sagging cantilever suspension.

 

Thanks guys. Sorry my post was too brief, I know the SRA is off and 92 degrees is ideal, but I wasn't sure I was measuring the stylus from the correct point. So a super fineline stylus has a centered contact point?

 

This is one crusted stylus... ohhh man! First of all, it needs cleaning with cleaning fluid, even then, may require multiple cleanings. (really tough to remove) Please use the 45/45 degree back to front method. Even better is a 60/60 degree pattern so the cleaning brush comes into contact with the front surface... where most crud accumulates.

Mentioned above by avanti1960. the rake angle is way off. It needs to be 92 degrees. (under actual tracking force) If your arm has a VTA adjustment, you're good to go. If not, I advise to shim the cartridge with a strip of folded paper. The shim needs to be placed across the front of the cartridge body. Snug your screws, be sure to not crank them too much.

Nice job getting a clear photo,
rock on,
Steve VK

 

OK I think I'm getting closer:

 

First off, good pics -- what USB 'scope are you using?

My question is really for anyone who does this and can get good images -- what are you referencing that red upright line to on the stylus? I'd worry that I could impose a 92deg to an image just cos it looked right, not cos I was actually drawing it through a defined set of points, if that makes any sense.

 

What 'table is the cartridge on?

 

Thanks. I'm using this microscope:

https://www.amazon.com/gp/aw/d/B0184CCOY0/ref=yo_ii_img?ie=UTF8&psc=1

Your question is the same one I'm really asking here. Though after zooming in further, as seen on the second set of pictures, it becomes fairly clear where the line should go.

 

Nice! I'd been considering getting a microscope to do this, but the cost of the one Fremer recommended made me hesitant. However, at $90 I think I must finally pull the trigger. Does it come with the measurement software?

 

I am keen on buying one of these microscopes too. How did you take the side on shots of the stylus in situ? It looks like the stand only points the microscope straight down.

 

Looks fine now. What would be the reason for exactly 92deg?

 

Kuzma Stabi M

It comes with software but I'm not even sure what it does. I just used a protractor app.

The stand rotates.

See here: http://www.analogplanet.com/images/512MFVTA_article.pdf

 

Thanks. Did you use ImageJ?

 

I sent the photos to my iPad and used the Field Protractor app.

 

I see. Thanks. I think I'm finally going to give this a try.

Was there a noticeable improvement in sound?

 

In a word, yes, a noticeable improvement. I'll add though that I wasn't as far off as those first pictures indicated. I had just relocated and reassembled my table. I ran through a very quick setup but wanted to put the microscope to the test. Where it ended up was very close to where I had it by using a jewelers loop. But frankly, using the microscope was much easier than my "manual" setup procedures I've been using for years.

 

Great, thanks. I'll be interested to see how close my setup was to 92 degrees (or not).