Problems with DIY mic (WM-61A)

[Phatman91624]

I built a mic using the Panasonic WM-61A capsule, using the linkwitz mod. I hooked this straight to my soundcard with an 1/8" mono connector. When testing the microphone using the windows sound recorder utility, all I get is a loud hum. No sound made is discernable except for very loud things such as blowing into the mic, and then it only serves to change the pitch of the hum somewhat. I was under the impression that I would not need a mic preamp for this to work out, but now I'm thinking that may not be the case. What are some other possible problems? Did I fry the electret capsule while soldering? Bad connection somewhere? Thank you for your help.

Mike

[Dave]

You will need to use a pre-amp with the capsule, here is a good example.

http://www.gti.net/wallin/audio/preamp/preamp.html

That could probably be modified to work with the linkwitz mod.

Connect the output of this into the line in input on your soundcard rather than the Mic Input.

[Phatman91624]

Thanks for the link. The problem is, that preamp seems failry complicated, and looks like it may be expensive. The whole goal of this project was to get a measurement mic for cheap. Does anyone know of any options that would cost me less than $20 that could get this mic working well?



Would this work so long as I kept the cable length short? Thanks

Mike

[5th element]

My preamp would cost less then $20 to make. All I use is a very simple opamp gain stage, with the relavent bits with the mic for the phantom power supply.

The thing that intruiges me is that the capsule should work with a computer mic input but you will have to still use a cap and resistor with the mic capsule for this to work.

Computer mic inputs use a stereo jack. One connection is ground, the other is signal input and the third is a 5 volt supply for the phantom section.