This Instructable will show you how to convert an old CB radio microphone (Astatic D104) into a computer microphone.
You can get these high quality chrome plated brass microphones at yard sales and on E-bay for very little cash. I chose this type of "lollipop" microphone because to talk you simply squeeze the neck and it turns on. It also has a locking ring to lock it in the on position. its also very sturdy being all metal and to me has that "retro" look.
Their are also several different kinds you could choose to convert as well, its a simple operation.
Your computer will not be able to drive the old CB microphone element very well, so we will replace it with a store bought one.
Next up parts and tools.
Step 1: Parts, Tools and Supplies Needed.
Astatic D-104 Microphone or similar. (below are some other types you could convert)
One computer microphone with cord (everything you need to upgrade in one package)
Tools and supplies
soldering iron with solder
1/4" heat shrink tube
NOTE :should you find another type of microphone to convert, check Ebay for its current market price, you could have one worth allot of cash. An example is a microphone that looks just like the one being converted here, but its gold plated and has an eagle on the back of the head. This is the Golden Eagle version made in the seventies, worth a few hundred bucks!
So be smart and research before you convert.
Step 2: Getting the Microphone Base
I started by taking the base apart and cleaning it.
Take off the base plate by removing the three screws.
This one had an old circuit board and a badly leaking 9v battery this was the pre-amp.
I simply cut that out and left any wire that was running up the neck as long in length as I possibly could. Some of these wires will be used in the conversion.
The old cord was held in place by a clamp, this was loosened and the old cord was discarded.
The base was painted dark tan but was very scratched, so it was sanded and painted with Krylon "hammered" paint. This makes a strong hard finish that has that "equipment" look and feel.
The rest of this microphone is chrome so it was cleaned and polished.
Step 3: Getting the Microphone Housing Ready.
The D-104 has four screws holding the face and back plates on.
It looks like mine had been dunked in water a few times, so allot of cleaning was done.
The only thing inside of the Microphone head I kept was the black fabric and the windscreen, this was used to keep the user from making popping sounds.
Depending on what computer microphone you end up using you may or may not need this.
Step 4: Taking Apart Your Plastic Computer Microphone
Now take apart your computer microphone I used a fairly cheap one so all that was required was to pop off the front and saw a small slit in the side and force it apart just enough to get the condenser microphone out.
After you get it out, cut the cable leaving an inch of wire on it.
Step 5: Mounting the New Microphone
After you take apart the top of the Astatic you will notice that it has nothing to mount your new condenser to.
You can use a piece of cardboard cut to fit or if you have some thin balsa laying around from another project like I used its soft and easy to glue.
I started by using the microphone head for a template and cut two wooded circles, one for the back and the other one to be cut in half and used as a sound guide.
I used super glue and epoxy to hold all in place.
Step 6: Mounting the New Microphone Continued
Now solder the new condenser microphone to the two wires in the microphone head.
The Astatic microphone has a removable head so you will need to make sure of polarity the insulated wire in the two conductor cable is the positive the other the negative.
Be sure to use the heat shrink and if your using cardboard make sure that the wires never touch the metal housing, this will make a nice buzz when you touch the microphone.
Glue everything down with epoxy.
Drill four holes for the screws and reassemble the head.
I used the foam black wind screen that came with it to cut down on pops and crackles.
Step 7: Wiring the Base
Remove the neck from the base and take the switch out,
You will notice that two wires run to the plug on the top, if you want a microphone thats always on, just wire your cord to these.
If you want it so that you can switch it on and off like the original, use a couple of the connectors on the switch to break the connection of the positive lead.
I also cut off all the wires that were not to be used, If you wanted you could use the switch to activate something else, you could build some voice effects into the base and use the other contacts to activate it...
Also pictured below is a simple wiring diagram.
Step 8: Wiring the Base Continued
I used the bottom set of connectors on the switch, that way when you squeeze the handle it comes on, you could use the other connectors and make it work the opposite way.
After you decide what switch you will use connect the negative wire to the cable and the positive from the condenser microphone to the switch, then from the switch to the cable, completing the circuit.
Reassemble the base as shown.
Step 9: Finished
You now have a computer microphone that will last for years and looks great to.
Hope you enjoyed this conversion thanks for reading,