mark18

anyone try this with smd components? if so, what did you use? i'm thinking this can be made smaller by using smd components. use 6 1.5v watch batteries, though i'm not sure how long it would last and what the trade off in cost would be for the batteries. i did make one using this schematic in a mint tin. mounted the jacks in the bottom of the tin, so the only way you can tell it's a battery box is to turn it over. i mounted the capsules in 1/4" diameter brass tubing. covered it with shrink tubing and riveted on an alligator clip. came out VERY nice.

good advice, that's the way i did it and it made it very easy. also use some clips on the capsule to act as a heat sink and absorb some of the heat.

one more question - are some caps recommended over others? for example, on the head-fi.org forums, the diyers all like black gate and nichicon capacitors in their audio circuits. would they be of benefit here or would any generic caps/resistors do? thanks!

what's the mAh draw? would a 12 volt, 59mAh battery work? http://www.batteryspace.com/index.asp?Page...&ProdID=914

ok, i'm going to repeat this to be sure i understand it. generate a 1k tone, hook up the element to a multimeter with a capacitor and measure the voltage. find two capsules that deliver similar ac output and i should be good to go. what size capacitor would i use as a coupling cap? would this work for testing: wire up the capsule and battery box. plug them into a recorder (ihp-120 in my case) keeping the mics as close together as possible, record a sample, compare the frequency response of the two channels. if the differences are minimal, you have a match. last question - if all else fails, where can you find a pair of matched capsules?

ok, i'm finally going to attempt this. before i do, i read someone you need to match the capsules. i searched this thread a couple of times, so i must have read it elsewhere. how do i go about matching he components? do i just measure the resistance with my multimeter?

n00b here. using these mics and battery box, do i still need a preamp?

very cool project. can you recommend some good sites to learn design. i've been looking around and found sites with circuits but nothing that will help one to learn about designing their own. i'd love to see a circuit to record audio to an sd card. put that in an altoids tin and along with your battery box and mics, you'd have the ultimate stealth rig! (i know that's a pretty ambitious project, but i'm willing to learn). thanks, mark