Art Barrios - Electrical Engineer / Software Developer
Thursday, January 10, 2013
Talk Box Megaphone Conversion
My father was practically a hoarder. A hoarder of any item that could remotely be useful for any purpose whatsoever at any time in the future. I am fortunate to have been the the recipient of one of these items - a professional megaphone.
My teenage son who plays the guitar asked me if I had ever used a talk box when I played electric guitar. You know like the one Peter Frampton made famous back in the 70s which makes your guitar sound like its talking. I told him the story of when I took a small radio speaker, a aluminum funnel, a small wooden box and some sofa cushion foam and made one when I was about his age. The next logical step was to build another one of course. I immediately thought of that old megaphone I had been saving in my attic for over 20 years and the gears started turning. DO YOU FEEEEEEEEL? LIKE WE DO!
The really great part about using a megaphone to make a talk box is that it already has a driver that is perfect for use in a talk box! In addition it has the parts needed to protect the driver from being blown. Here is what we had after dissembling it.
Here is a hand drawn schematic of the talk box that my son and I made together. All the required parts were available from the tear down.
This is the transformer, lamp and capacitor from inside the megaphone.
My son's older brother then came in to help finish the project. Together they drilled out a section of the mouth piece and reversed the driver so that it pointed out the back of the megaphone. They then hot-glued a piece of plastic piping and filled in the area around the driver with insulation to keep the sound level as low as possible. After installing a 1/4" jack in the side of the bell and soldering up the wiring according to the schematic it was ready to go.
The finished product - one that Frampton himself would be proud of!