SRA is still important. So we were recently alerted to a 45X LED microscope that gets close enough and big enough to let you know if your SRA is at least in the ballpark.
We bought one and following the same instructions we provided for using a digital microscope, which you can find on this website, we placed a CD on the platter, moved it well beyond the platter's edge and lowered the stylus onto it.
You have to carefully approach the stylus with the eyepiece and its illuminating LED and after a few frustrating minutes you'll be able to locate the stylus sitting on the CD. Though the view will be fleeting unless you have really steady hands, it should be long enough to see if your SRA approximates 90 degrees (you want 92).
While you can't use this device to get a precise setting, by knowing if you're even in the ballpark is better than not knowing and you can then adjust from that starting position at least knowing if you're below or above 90 degrees.
You can get one for $7.49 at Overstock.com
COMMENTS
At $300 or so for a USB model I can eyeball the overall situation and listen to the effects. In other words, skip it. But only because it's not in the budget.
At less than $10 I can play with a cheap piece of shit and feel good about it for a while longer.
Thanks for the tip!
For those not living in the USA who want to try these, it can be bought for about $4 at dx.com (from China). It takes a lifetime to be delivered but it's free shipping (at least to Brazil) and they deliver worldwide (unlike overstock.com and amazon.com). I bought a 60X for $4.10. Hope to test it before Christmas :)
As most people now have a digital camera of at least 2m megapixels, or even have one on their phone why not use that to capture the image of the stylus.
It might take a bit of balancing to get the angles right but you can get a really good image and adjust it to be horizontal using free image software and then use a program like MB ruler to measure the angles on your image.
Here's a photo I took using a cheap Canon digital camera of my stylus http://i787.photobucket.com/albums/yy154/MokoMilk/New%2012%20Arm/IMG_000...
I hope this helps.
Great idea...should have thought about it before purchasing the microscope...but for $4 with free shipping that's not much money wasted if I end up not using it. It would make a great toy for my daughter anyway.
Just to try to help further, if I understood it correctly, you actually don't need to get an horizontally aligned picture, or even make it so with a software, all you need to do is measure the angle between the cd surface and the stylus (whichever method chosen). It doesn't matter if the cd surface is at an angle in the picture, am I wrong?
You should however try the best to get the camera parallel to the cantilever in order to get a correct reading of the stylus angle, as pointed out in the original article.
I guess the photo wouldn't have to be straight to measure the angle between the stylus & the CD surface, but I couldn't find a way to rotate the measuring scale on the program I used (MB ruler) so I decided to rotate the photo instead and base the measurements on the horizontal.
If you know of a better free measuring tool please let me know (I did try an old maths set protractor placed over the photo but it wasn't that accurate!)
I spent forever trying to find the horzontal plane. But, using the measuring program that came with my $99 'scope, I can measure the angle of the stylus shank in relation to its reflection. 2 x 92o (one up, one down) is 184o. My tool measures the 176o adjacent angle but it still adds up to 92o SRA (or pretty close as in this picture). Thanks Mikey! At least there's something right in this imperfect world...
There is a reasonably priced USB microscope on amazon. I realize it is not as cheap as the one mentioned in the article above but, it is still a pretty good value. It is a 150X that is made by celestron. I have a telescope made by celestron and it is good quality. I can't speak of the quality of this particular microscope but, It has numerous good reviews on amazon. Check it out below......
You can check it out here as well on the celestron website. They have some videos of it being used on an ant there. Looks like it shows pretty good detail.
http://www.celestron.com/science_education/microscopes/deluxe-handheld-digital-microscope.html
Ordered it Wed. If nothing else it will help me read the mastering codes off the lead-out area of my lps.
Now that would be a reference book I would buy. A deciphering code book of all the mastering engineers and companies.
I think I gave the EMI codes somewhere on the site. I can also give the UK DECCA codes... I think I will soon..
Could it not be attached somehow to a table tripod? Or am I oversimplifying the situation.
I would also love to have a list of codes Michael.
Mahalo for all you do for us licorice disc junkies!
Just a note regarding the comment of setting SRA precisely at 92 deg.; it's actually SRA accuracy that's important. Accuracy reflects the degree of bias of a measurement relative to a standard (which represents the truth), the truth being in this case whether the SRA really is at 92 deg. Either the SRA is at 92 degrees or it isn't; the key is to have a measurement system that can detect that if said measurement achieves the standard (92 degrees SRA), and if not, by how much it is off (the degree of bias).
Precision is a measure of the variation that occurs from a set of many measurements of the same thing (or dimension), and can only be assessed from a number of repeated measurements, not a single measurement. It is usually assessed by the statistical parameters for measuring dispersion in normally distributed population or sample set of continuous data: variance, standard deviation, or in some cases, the sum of squares of the measurements-note the plural, measurementS.
Therefore, it is possible to have a very precise measure that is completely inaccurate (a set of many measurements at 90 deg with a small standard deviation), and also possible to have an accurate measurement at 92 degrees that is imprecise (large standard deviation).
I've used a USB microscope and attendant measurment software and found it can be challenging ot measure the SRA accurately...I've found that it's very easy to take repeated measurements and get an inaccurate measure of SRA because how one draws the line using the software from stylus tip to cantilever can easily vary due to a lack of precision in the mouse or tracking device.
If you've got a digital camera with a macro lens, or macro attachment, you might not need to buy a digital microscope. Procedure I used for my Lyra Delos:
1) I put my Nikon D300 on my tripod, with a Nikon 105mm macro lens attached.
2) Turned on the grid lines in the viewfinder, to allow accurate alignment of the camera to the platter.
3) Focused using zoomed in Live View on the digital screen. If you've got a tether cable to go from the camera to your laptop, this will be even easier.
4) Imported the photos into Photoshop for image adjustments in Camera Raw, then crop and zoom in on the stylus.
5) I then used the Measurement tool to draw a line through the stylus, which calculates the angle.
Would put in a screen shot if I could figure out how to do it with this editor...
What to do if it's impossible to get it at 92 degrees, or even 94...
My cartridge has low clearance, and the back of the cartridge body is just about touching the record... if I were to play a record with a warp, it would bump the vinyl as it's spinning. But the stylus is clearly a few degrees forward. It seems as if my cantiliever needs to be pulled down from the body a bit, but I don't want to try anything like that, for fear of causing another problem, or snapping it off.
from eBay. Comes with a little leatherette (pleather?) case. Seems to produce an upside-down image.
ProTip: Don't point the thing at you when flipping on the LED light. Oy!
BetterTip: Thanks samman, regarding the lens shield.
Been playing with it, looking at keyboard chiclet letters and on-screen text but so far the image seems roughly same-size as real. Hope I can get this thing close enough to the stylus. Gonna need something to hold it.
We'll see about this one, Mike. I do think I will pass on the USB microscope, I know ignorance is NOT bliss, but I rather not futz too much with SRA and or other tonearm/cartridge setting beyond what my by-eyeball set-up tools allow -- I'd rather listen to music. But I couldn't pass up the price of $6.98 at Amazon.com for the mini-microscope/LED that you recommended, to at least see if "I'm in the ballpark". Hey, wasn't $6.98 the list price for most domestic LPs in 1979? !! .
You can use a 4 X 3 inch index card with parallel lines (used for a roller deck) and draw in a line at about 2 degrees to the horizontal lines on the card (the angle will be such as to raise the arm at the pivot). Place the stylus on a CD as before and sight at RIGHT angles to the arm so that the arm is parallel to your 2 degree line-raise or lower the arm as needed. That will get you into the ball park even ease than fiddling. You will stand the card on its edge to do the sighting
I just purchased a 60X version of the pictured item from ebay for $5.29 with free shipping. Here is the link
http://www.ebay.com/itm/261181885219. Hopefully it will help me to set my SRA correctly.
M~
There is a tool catalog retailer called Garrett Wade, they sell a 60x - 100x pocket microscope for less than $20. If you want a smart phone adapter so you can photograph the image it is under $30. They have apple and android adapters. Figure out a way to level and hold the scope still and it should do the trick no problem.
Since it's currently out of stock, I did a research and found it available at Abe's of Maine. But since their reputation is a bit controversial, judging by what Abe's of Maine customers say at consumeraffairs, decided to look elsewhere. Do you have any suggestions?
Got me one of these - with a removable stylus you can get amazing resolution of your stylus. $17 CDN so what is that? 15 cents US$
Anyway - pleased as punch with this very cool device with many purposes....
http://www.amazon.ca/Carson-60X-120X-Lighted-Pocket-Microscope/dp/B00LAX...
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