CR element adjustment
I have a Shure CR element that does not work. It ohms out fine at 1185 ohms but I can only get
it to work if I push slightly on the pin (pickup) on the front of the element. When I release audio goes dead. IF I push to much audio also goes dead so it appears something is out of adjustment.
Is there a way to adjust this or is the element trashed? Also I have another element with the 3 screws broken off. The 2 screws that go into the standoffs. What size are these screws? Do you know where I can get them.
Regards,
528hemi
OK so I took everything apart and read some notes on how this CR works. I put it back together and had to glue the disc back to the pin on the diapham. I used normal white glue. This thing is now very strong!!!! I gues the orginal issue was the glue on the disc must have dried and caused a low output. I did not know what to look for so started to tinker. These elements are pretty simple in design. Now I understand more and can tweak them without being scared to break them.
So the question now is, If I have a good CR but not as strong as another, Does it mean the glue could be partially causing this? Ha....I guess if it sounds good dont tinker with it. :) My curiousity is wanting me to take a good element and try to make it better. What do you think?
528hemi
"Tinkering" is something many of us are simply compelled to do. Rewarding, yes. Risky, sure. Be prepared to lose a subject or two in the process of finding the answers you seek. It's the price of admission...
"I used normal white glue." If you're referring to a water-based 'Elmer's' type of glue, I would advise otherwise. My experience with these "all-purpose household cements" is that they cure retaining a degree of doughy flex and never harden. As this would act like a shock absorber between the collector and the pin, it stands to reason that less vibration would be conducted between them and thus yield less audio.
MIC MORSEL: A small amount of an adhesive that cures very hard (conductive physical properties) yet not brittle is what you're looking for: There's a cyanoacrylic "super" glue that contains fine black rubber dust, giving it a bit of "flex" while curing quite hard; There are two-part epoxies that might fit the bill as well. Report back from the front when you can...
Where does the time go? I spent HOURS down in the MIC DUNGEON today and tonight, connecting all manner of Mic elements to all manner of raw audio transformers -not the ready-cooked in-line variety of 'matching transformer' but the little raw guys you find inside (primarily dynamic) microphones. The ones with mysterious multi-colored wires dangling out of their windings. Alligator test leads in hand and amp at the ready, I tested literally dozens and dozens of combinations. Yes, some very COOOOOL results and surprises a-plenty!
OK... Even if you've always hated homework, you just might like this: Get out the test leads & assemble a heap of parts from your 'junk drawer' (I'm convinced everybody's got at least one) and start mixing and matching -AND SHARE WHAT YOU FIND OUT! The good, the bad, the ugly -and I'll do the same. I bet you'll have some questions.
Time sure flies when you're having fun...
Hey Fritz or anyone, I've got a Shure 99B86 CM element that tests out ok for ohms, but when wired in it sounds very trebley and not as strong a signal as others I've tried. Is there a way to clean it or some way to get more low end tone out of the element? It seems that if the pin traveled further in the magnetic field, it would sound deeper. Is this something that a cleaning or some kind of adjustment could help with? Thanks to anyone with an answer! Tom
Hello Tom,
There are a couple of possible causes for your CM's behavior. If its electronic properties are indeed "up to spec" then investigate the physical aspects of its performance. Absence of low frequencies may indicate a physical impedance to the free movement of the sound collecting mechanism. It's not uncommon for a vintage element -or any CM/CR element with a load of miles on it- to collect "dust bunnies" between the conical cover plate (looks like a '50's DeSoto hubcap) and the foil collector beneath it. Bits of grillcloth fuzz, tobacco, wayward crumbs of food, and general lint can work their way in and not find the exit on their own. Care must be taken to not damage the delicate foil collector when attempting to clean this gap. Don't insert any hard pointy tools that might kink or puncture the foil. First, try blowing across the face of the CM/CR. Try varying the angle and pressure as you go... MIC MORSEL: In some cases I've used alcohol to dislodge the stubborn chunks. Common Isopropyl alcohol will work. Traditionalists might favor vodka or gin. Typical method: Hold the CM/CR face down by its magnet and dip it into the liquid, covering the disc of the collector. Remove the element from the fluid and give it a good hard shake to clear liquid from the cover plate. Let it dry thoroughly, face down on an absorbent cloth. You might find bits of debris collected around the vent holes in the cover plate that can now be removed -with care- using a toothpick or tweezers.
Another problem that occurs involving foreign materials in the CM/CR is the collection of tiny metallic fragments in the magnetic gap inside the element where the actuator attached to the central pin passes between them. These little chunks can sometimes obstruct the free movement of the actuator bar. I'll be back with a couple methods for dealing with these troublemakers that don't require a SEAL team or NSA clearance...
Hey 528HEMI,
The fact you've got continuity thru the transformer is of course a major plus. As for the nature of the problem: Eliminate the possibility of any physical obstructions around the collector plate and central pinion. Nothing? Look into the magnetic gap through which the pick-up bar protrudes to the center pinion. The word "gap" is the key here. if there's contact between them within the gap you'll get zip signal. Take a toothpick or other hi-tech device and gently try to move the bar to see if it has clearance in either direction. It's easier to tell if the element is hooked-up while doing this.
MIC MORSEL: I've never seen the following 'fix' published anywhere & I don't recommend you try this next step unless you're willing to take responsibility for the outcome...
Insert something small and metallic (small flathead screwdriver) into the magnetic gap and gently twist it in order to pry the magnetic gap open JUST A HAIR. Test for audio... I've achieved positive results doing this to CM's and CR's that otherwise would not produce audio signal. Report back with your results, soldier...