Lately I have been researching the many different ways people have installed sound amplifiers into their helmets. I saw a video on youtube by drunken mynock that inspired me to install one in my bucket. I found a few different pcb amplifier kits available online, but decided to try to find something local. I found this kit at Radio Shack called the Velleman Super stereo Ear Model: MK136 | Catalog #: 277-098.It has right and left mic inputs and outputs the stereo channels separately. Which is just what I wanted. Most the kits with two mics are mixed into mono out and I didnt want to use two separate amps. The kit was only $15.99.
It is very easy to assemble and comes with good instructions. All you need tool-wise is soldering iron(40 watts or less), nail clippers (to cut off excess wire after soldering), and solder (I used 60/40 clear flux on this project, but you can use whatever you like). Assembly only took about an hour and a half.
I got my old sony headphones and mounted them onto the ear bolts with lock nuts. Then I installed the two mics just as I had seen others do it, on the sides behind brow trim.
I wrapped amp in electrical tape and mounted it with velcro. It sounds great and saves me room since i am using only one stereo amp.
This is my first post and I didn't intend this to be a tutorial since there is already many ways to do this. I was just stoked to find something useful at Radio Shack for once.