Sparky's Fabulous DIY Stylus Microscope

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Karma16

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Such a humble title, don’t you think? After the interest shown concerning my initial thread titled “Stylus Microscopes”, and the general unavailability of used Shure SEK-2 stylus microscopes, I decided to try a DIY stylus microscope project. The thought is that dedicated DIY’ers can build an adequate microscope if they had a model to start with. Here is my version.

Before you read what follows, I suggest you read the original thread at:

http://www.audiokarma.org/forums/showthread.php?t=87723&highlight=stylus+microscopes

The manual for the Shure SEK-2 Stylus Microscope can be seen here:

http://www.shure.com/idc/groups/tech_pubs/@global_managed/documents/webcontent/us_pro_sek-2_ug.pdf

The Basics
Several of the posters in the original thread tried various home-made scopes usually based upon computer centered instruments. I felt they showed promise but the inventors were disadvantaged by having never used the SEK-2, making it difficult to build a useful instrument.

So, my goal was to build a stylus microscope as good, or better, than the Shure SEK-2. The cost should be such that anyone can afford to build the instrument using parts that are commonly available.

The basic requirements for this stylus microscope are:
• Variable magnification. It would be nice if it is built into the scope but mine did not have this feature. I had to find an alternative. I’ll explain below.

• Minimum magnification should be about 50X. This is used to position the stylus in the viewing field. 50X is not critical but it is the most useful magnification for the purpose and is available with common lenses.

• Maximum of magnification of 200X. More than this is a disadvantage. Less is not enough.

• A 10X objective lens (the one on the lens turret). This magnification has the advantages of adequate depth of field and good working distance. Many scopes have this objective lens.

• A micrometer adjusted X/Y axis stage. This is the platform the specimen (the cartridge or stylus, in this case) rests upon. This is an important feature for a successful microscope design.

• An effective and inexpensive lighting system.

• Easy to use and set up while posing no danger to the stylus while it is being viewed or positioned.

• Does not modify the original scope so it can still be used as a normal microscope.

• Useful. Gives definitive information to determine the condition of the stylus.

• Inexpensive; a relative term if you have to buy the scope.

As you can see, there are a number of requirements that need to be satisfied to make a truly useful tool.

For those of you not familiar with optics, the overall magnification of a multiple lens system (in this case, 2 lenses) is the magnification of lens 1 (the eyepiece) multiplied by the magnification of lens 2 (the objective). For this project you will be working with two eyepieces (5X and 20X) and the objective lens (10X). If the eyepiece is 20X and the objective is 10X, the overall magnification is 200X, our goal.

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What Do You Need?
The following basic things are needed to duplicate the instrument in this project. All of these items are covered in detail below. Some will have to built.

1. A basic laboratory microscope.

2. A set of the proper eyepieces.

3. The correct objective lens.

4. A good and appropriate lighting fixture.

5. A mount for your cartridge, head shell, or arm wand.

No special tools are needed other than normal shop tools. Nothing complicated.

The Microscope
I started with an Olympus CH binocular student laboratory scope. This instrument is serious overkill but it was what I had on hand. A binocular scope is not necessary. If you have one, it will not be used with both eyes at the same time. But a binocular scope does have some advantages. I mount the 5X and 20X eyepieces at the same time. This lets me position the stylus in the view field using the 5X and then move to the 20X for critical examination. It’s very easy to use but not absolutely necessary. A single tube scope would work just fine and is much cheaper. You would simply switch out the eyepieces.

My Olympus scope has a variety of objective lenses on its four lens turret which included a 10X. The 10X is the basis for the projects optical system. With the 5X and 20X eyepieces, magnifications of 50X and 200X are available which are perfect for this job.

Do not discount the micro-adjustable stage. I consider this to not be optional. Most modern microscopes are provided with one. If not, you can buy one at microscope suppliers like Edmonds Scientific. Do it! This is a bad place to economize.

Since the cartridge or stylus must be positioned directly under the 10X objective, you must find a way to cover the hole in the stage through which the normal scope illuminator provides light. I just use a sample glass slide with which the slide clamp works perfectly. I then set the cartridge on top of the slide. Of course, the normal illuminator is not needed and is turned off.


The Eyepieces
Searching on Google to find a zoom eyepiece, I found nothing. I thought this was strange because I was sure I had seen them in the past. I gave up on finding a zoom eyepiece. I settled for using a combination of low and high magnification eyepieces. This is probably not a bad situation because the eyepieces are inexpensive. If I insisted on Olympus brand lenses, it would have cost hundreds of dollars. Olympus lenses would have been optically faster and better but, for this project, what I bought are perfectly adequate. If you can find a better solution, go for it and let us know. The only constraints are the size and magnification of the lenses. Do not be tempted to go to higher magnification. It will not work as well. Links are provided below to purchase the eyepieces I used.

Be careful when buying eyepieces. The diameter of the stock 10X Olympus scope eyepieces is 23mm which is pretty standard but there are other diameters. Measure yours and buy the proper one. On my Olympus, the eyepieces can be interchanged by simply pulling the eyepiece out of the tube and slipping in a replacement. Be sure to check that your scope can interchange eyepieces.

Here is an ebay link to the 5X eyepiece (Brand Name: AmScope Model No: EP5X23-S):
http://cgi.ebay.com/ONE-COMPOUND-MI...5|66:2|65:12|39:1|240:1318|301:0|293:1|294:50

Price: $29.99

And here is the ebay link to the 20X eyepiece (Brand Name: AmScope Model No: EP20X23-S):
http://cgi.ebay.com/ONE-WF20X-EYEPI...5|66:2|65:12|39:1|240:1318|301:1|293:1|294:50

Price: $24.99

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The Lighting System
This is a very important component for the microscope. Unlike standard microscope under-the-stage lighting, the stylus microscope needs to be illuminated from above and to each side. This arrangement will allow the wear facets on the stylus to reflect light up into the eyepiece. A fair amount of light is needed due to the relatively slow optics of the suggested eyepieces. It is nice if a certain amount of ambient light is provided to show some of the context of the view. If the light is right, the wear facets will be obvious as very bright spots against a dark, but not black, background.

There is a broad range of lighting that will work. It’s up to you to get a good implementation. Some folks tried to use LED flashlights. While this is, perhaps, OK for experimentation, LED’s just don’t put out enough light to be truly useful and they are difficult to mount. I did a lot of web searching and found a number of light/socket combinations that might work. But, I did not like various mechanical elements such as the required mounting techniques. After hours wasted on the internet, I found my solution at our local hardware store. I do not know how generally available these lights are. I have included all contact information I have below. The retailer site only shows the four light kit but they probably also carry the two light kit I bought. You should call them, or the manufacturer, for details.

The lights, a pair of them, are small 20W halogen cabinet lights. They are designed to be mounted either flush or on the surface of a cabinet. They are provided as a kit which includes the lights, a power transformer, a wiring harness, and all necessary connectors. The lights, reflectors, and lenses are mounted in a round plastic housing which surface mounts easily with two screws. All in all, they are reasonably well suited to this project. They are bright and don’t put out a lot of heat. Cost was about $20.00.

Model Number for the kit I bought: SR60LCS

A link to a web retailer:
http://www.decorativecents.com/under-cabinet-lighting-halogen-low-voltage-accent-lights.html

Company who manufactures the kit:
Westek

Address:
20 bond Street,
Central Valley, New York 10917

Phone: 1-800-777-0802

Mounting the Lights
Here, we have many options. I did not want to modify the scope at all and I wanted to keep it simple. I used steel bookends the base of which slides under the microscope base. This gives good stability and some adjustment capability. To these I bolted rectangular pieces of Masonite I had in my scrap pile that I cut to size. I painted the scope side white for good light reflection. Then I surface mounted the light housings to the Masonite at the proper height and alignment with the cartridge or stylus. I drilled holes to feed the wiring to the back side of the Masonite to keep it out of the way and not snag the stylus. I then secured the cords to the back side with cable clamps. The light mounts were easy to build and work well. Check out the pictures.

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The Cartridge Mount
Each potential microscope user could have one of several different cartridge examination possibilities. In the photographs that follow this article, I have shown a very simple case. It is a bare cartridge sitting on the stage. This is one possibility but does not represent the average case. For the microscope to be easy to use, the cartridge tone arm alignment should not be disturbed during examination. For example, most of us have tone arms that have removable head shells. The head shell can be removed from the arm and placed on the microscope. Then, after examination, plugged back into the arm and everything would be back to normal. This is how it should be done.

But, this case is not universal. In fact, there are several variations on this theme. They all have one requirement in common: if there is an alignment to maintain, it should not be disturbed by examination on the microscope. Period! Case closed.

Let’s look at the possibilities:
1. Bare cartridge (applies to arms which do not have a removable head shell or arm wand. This case would not allow the cartridge alignment to be maintained. The SME Series V is an example. However, B&O cartridges are a different case. These cartridges plug into the arm so alignment is not a problem.)

2. Removable stylus from a MM cartridge (examine the stylus only, without the cartridge)

3. Removable head shell (examine the stylus while still in the cartridge and the cartridge still mounted in the head shell. This would be the typical case for either a MM or MC cartridge.)

4. Removable arm wand (examine the stylus in the cartridge and the cartridge still mounted in the arm wand. This applies to many high end arms used with MC cartridges.)

There are more variables due to the microscope that is selected for this project. I am not a microscope expert. I am not familiar with all the possibilities that can be used. There are a huge number of scopes that could be adapted to this project, all with different stages and slide mounts. These things could affect how the subject of examination might mount on the stage. Usually, the subject stylus or cartridge is simply placed on the stage and you are done with it. But this may not work in all cases. Special mounts may have to be fabricated for your situation. Even the SEK-2 was not perfectly compatible with all the possibilities. Often, special mounts were needed. Usually, these were very simple.

Because of the variations, I am not going to try to define a cartridge mount. You can use your imagination to figure out a good way to deal with your situation. It should not be difficult. The mount could range from spacers to simple saddles.

My analog system presents a good example. My two turntables use Eminent Technology ET2.5 air bearing arms. This arm has a removable arm wand. I must examine the stylus while the MC cartridge (no removable stylus here) is still mounted in the arm. I need a special mount which is shown in the last picture. It is a simple saddle but because of the length of the wand, it must extend past the front edge of the stage base.

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How the Microscope Is Used
I assume you have read the Stylus Microscope thread I referenced at the beginning of this article. From this, you should have a good grasp of the concept and the vocabulary I use. You should also understand why a Stylus Microscope is the only valid and useful visual method for determining the wear state of a stylus we have available to us. What you do not have is a description of how the microscope is used. I’ll now try to fill that gap. I’m going to be very basic so do not be offended if I state the obvious.

I’ll use the removable head shell case as the most common example.
1. Set up the microscope on a stable, level surface. Turn on the stage lights.

2. Remove the head shell from the arm and place it on the microscope stage. Thoroughly clean the stylus with a cleaning fluid such as a commercial stylus cleaner or alcohol and a stylus brush. I use an electronic stylus cleaner. If you don’t do this you will see an unbelievable glob of junk on the tip even if you think it is clean.

Use care that the stylus does not come into contact with the objective lens. If necessary, use the focus knob to gain space. The connector on the head shell should be placed at the rear of the microscope with the head shell pointing forward. (In some cases, such as the arm wand situation, the wand will project forward which reverses the cartridge; this is not a problem. See my arm wand in Picture 8.)

3. Visually center the stylus on the stage. Don’t worry; the alignment will not be right initially. You will correct it.

4. Use the 5X eyepiece. Manually move the head shell around until you see the stylus in the field of view. This takes a little practice. Focus the image.

5. Use the x/y axis stage adjustments to center the stylus in the field. Focus the image.

6. Move to the 20X eyepiece. You are now working at a combined magnification of 200X. Re-center the image. This is where you will appreciate the adjustable stage. Refocus. If you did not center properly with the 5X eyepiece, the image may be completely out of view. It does not take much error at 200X for this to happen. If you cannot see anything useful, go back to 5X and re-center.

7. You will focus on just the tip of the stylus point. Most of the rest of the stylus will be out of focus and not recognizable. Again, this takes a bit of practice because the odds are you will not recognize what you are seeing. Keep playing until you see just the tip. Refocus if necessary. It will be easier the next time.

8. If there is wear, you will see the wear facets as bright spots, one on each side of the stylus tip. The more wear, the larger the facets. If you see large facets, it is time to replace the stylus or cartridge. If they are large, there is a very good chance you will hear audible distortion. If small, you may have not yet noticed distortion. Check out the pictures at the end of the article to see what the facets look like.

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How Well Does It All Work?
In a word, GREAT!! The double eyepiece approach is better than I thought it would be; almost as good as the SEK-2 zoom lens. Magnification is perfect. Image quality is good if not perfect. The lighting gives a definitive picture of the stylus wear facets and the depth of field is about perfect. Working distance under the objective lens is adequate to keep the stylus out of danger. There is no need to rotate the objective turret which would pose a danger to the stylus. Just select the 10X objective and keep it there.

Two things are very important. First, the microscope must not put the stylus in danger while it is being examined. Next: the scope must be easy and fast to use. This design accomplishes both of these goals. Of the goals and features noted at the beginning of this article, all are fulfilled.

I consider this Stylus Microscope project a total success. It works as well as the Shure SEK-2 and that is saying a lot.

The total cost of the materials I bought was about $75.00. Of course, this does not include the cost of the microscope. I hope you already have one lying around the house. If not, look for a used scope on ebay.

Summary and Conclusion
I want to close by emphasizing this was not a difficult project. I had the advantage of many years of experience with the SEK-2. Thus, I knew exactly what was required to build a truly useful instrument. That is the most important factor. Most of my time was spent on the internet researching parts. The lens magnifications are very important. You can use my experience to your advantage. If you use the same magnifications you will be successful.

The next most important element is the lighting. This seems, on the surface, to be such a simple thing. But, much of the success of the SEK-2 design is due to its lighting. The lighting I presented in this project is, I think, better than the lighting used on the SEK-2. The bottom line is not to take the lighting for granted. It can make or break the project.

Last, I want to restate the importance of the adjustable stage. With a magnification of 200X, the slightest movement of the stylus will move it completely out of the field of view. It is very difficult and frustrating to place the stylus by hand. Yes, it can work but it is a pain. Thus, the 5X eyepiece and the adjustable stage are important ergonomic elements of the design.

Check out the pictures that follow.

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1. The Completed Stylus Microscope​
 

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2. Stage Detail​
 

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3. Side View​

The rectangular hole is necessary to clear the stage adjustment mechanism used by my scope. Not all microscopes will need a cut out.
 

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5. Close up Of Cartridge​
 

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6. Wear Facets – an exagerated view​

Note: This was a very difficult picture to take. I had to hand hold the camera against the 20X eyepiece and move it around until I saw a decent image. The view the eye gets is less dramatic and shows much sharper edges around the facets. The facets are very bright against a dark gray background. The camera had a difficult time dealing with the exposure range. The bright facets against the dark background caused the facets to bloom. This is an indication of just how bright the facets are. I was forced to use spot metering. In real life the facets are bright white. The color shown is false. This image has been manipulated in Photoshop to improve the brightness and contrast. The image is magnified so I could show the general shape of the facets which were not captured well by the camera. The pixelization is a false artifact. It is a result of using the Photoshop sharpening filter.
 

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7. Wear Facets – a more realistic view​


This view is more realistic in terms of size and what you actually see through the eyepiece. Compared to the eye view, the contrast is low and brightness is reduced. The real image is sharper.

Lacking a better picture, I hope you will accept my evaluation of the real image the eye sees. The image is very good, at least as good as those seen under the Shure SEK-2. The facets are bright, definitive, and obvious. The depth of field is adequate to encompass the entire wear facet. The lighting angles are excellent. Image brightness is adequate with excellent contrast.
 

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8. Custom Mount for My ET2.5 Arm Wand​


Here is a detail view of the custom mount I made for my arm wand. It is made from sheet plastic. It has a cut out so the slide clamp can grab the mount and position it properly on the stage. The cut out can be seen on the right edge. The mount rests directly on the stage base. So, as you can see, a custom mount can be very simple.

If you attempt this project, I think you will be thrilled with the results.

Sparky Shaver
April 15, 2009
 

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Congratulations on your ingeniuity and dedication. Excellent idea. This has got to be the first thread going to sticky status within a few hours and without any responses.

Just an idea: Have you tried to mount a camera directly to the scope in place of the eyepiece? I have taken excellent pictures of microscope specimens in the past using a microscope adapter on an SLR camera. That will defeat the 5 or 20x magnification of the eyepiece but with an 8Mpixel digital camera, croping the center would compensate for at least 5~10x magnification.
 
HI SaSi,
Thanks for your nice words. I hope others feel the same way.

Are you going to try the project? If you are a vinyl type person, you will be glad to have a really good stylus examination tool. Until this project, almost nobody had the realistic option of having a stylus microscope. It least I think this is true. I've never heard of another DIY scope. The Shure microscope is rare to an extreme. Don't expect to find one.

Taking pictures through the scope was not a priority. For my own use, I don't need to do it. I don't think it is very useful. Notice it was not on my priority list at the beginning of the article. The only reason to photograph through the scope was to illustrate the article. The picture of the wear facets were done simply to show what they look like through the scope and to demonstrate that the scope really works.

Could they be better? Sure. If you have the adaptors, go for it and post here. I'm sure many would like to see better pictures. Personally, I'm done. I'm happy.

Sparky
 
Great work! Can you correlate the amount of wear shown in the sample picture with what hear? i.e. will that amount of wear be very audible or not? thanks
 
HI ej,
Thanks. Yes, this amount of wear would have been audible. Wear almost always is. Your ears are the best judge. Just how audible is lost in the mists of time. The microscope is used for conformation that it is wear and not something else like tone arm set up.

This is an old Accuphase that has not been used for a long time, maybe 30 years. I did not have a microscope available to me at that time. If I did the cartridge would have been changed out before the wear became so obvious. I probably was out of money.

I wanted to make the wear facets to be obvious to those who are not practiced at looking at them. I would consider this cartridge past the point of prudent replacement.

Sparky
 
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