µMicrophone

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This microphone is easy to make and sounds good for close-up miking. It is especially nice for miking stringed instruments. The primary component for this microphone is a Panasonic condenser microphone cartridge.

primary components needed:

• Panasonic Microphone Cartridge (WM60-AT)
• 1 µF capacitor
• 2.2 kOhm resistor
  
  
other parts:
• 26 gauge stranded wire (~ 10 ft)
• 1/2" heat shrink tubing (~ 2 in)
• 9 volt battery
• 9v battery clip
• 1/8" or 1/4" male phone jack for connecting to audio equipment

Figure 1 shows the basic circuit for use with the microphone cartridge. C1 = 1 µF. Using a 1 µF capacitor sounds the most natural; however, for more bass sound a 100 µF or 1000 µF is good. R1 = 2.2 kOhm.

Figure 1: Basic microphone circuit

Other considerations

• you might want to coat the back of the cartridge when it is finished with some sort of sealant to prevent any grounding noise when holding it.
• black colored wire might be nice to minimize the presence of the wires, but make sure you know which wire is which if both wires are the same because the wires cannot be switched.

Alternate circuits

Figure 2 shows some additions to the circuit diagram shown in figure 1. The components C2=1000 µF and R2=R1/10=220 Ohms are used to prevent clicks when attaching or detaching the battery from the circuit. C2=100µF is also good but allows more click sound. C2 less than 1µF doesn't prevent much clicking at all. Adding C2 and R2 will slightly lower the amplitude detection of high frequencies, but not greatly.

R3=100kOhm can be used to discharge the C1 capacitor to prevent clicks when plugging in the microphone. This resistor causes a somewhat noticeable decrease in higher frequencies.

Figure 2: click-prevention circuit

Stereo version of the microphone:

Figure 3: stereo microphone

Other links:

• http://www.prolectron.com/elect -- some circuit diagrams which include the Panasonic condenser microphone.