Easy Homemade Headphones

It only takes an hour or so to turn a set of shooters muffs into a sensitive set of headphones for your crystal radio. The first thing to start with is the transducers you wish to mount in a set of shooters muffs. The photo below has a series of Radio Shack piezo elements that all work with xtal radios. The picture shows them from left to right what your EIC believes the best to worst. The smallest element is near worthless for xtal sets but I put it in the picture so you'd know what to avoid.

Your local hardware store will sell hearing protection muffs in thier power tools section or your local Wally world sells the same items as shooters muffs in the sporting section. There's ample foam in most of the muffs I've bought to hold the elemets firmly against the rim of the plastic cup of the muff. If you land a pair that's shy on foam a little extra from common pillow foam can be packed in behind the element to hold it in place. There's three holes to drill. One in the top of both cups, and one hole in the bottom of one of the cups. Simply pull the foam out, drill the holes, route your wire of choice as shown in the picture, pack the foam back in, insert the piezo elements and solder a headphone jack to fit your radio on the end of the headphone cord and your pretty much done. You can wire the elements in series or parallel, I wound them in parallel. Feel free to experiment what works best with your radio set.

The set below was made using old Ma Bell telephone elements. What's special about these? They have built in impedance matching transformers. This little transformer is a TRW M27/172-38 which gives you a step down of 20k to 800 ohms and is about the size of your fingernail. I taped two together, wired the primaries in series and the secondaries in parallel and stuffed them behind the foam of the headset. The elements in this set were wired in series. This is one of the more sensitive sets I have and a pleasure to listen to.

If you want to have more fun with the piezo elements and have some REALLY strong locals beaming down on you try a horn speaker. This is just a transmission fluid funnel and a Radio Shack piezo hot glued together.

I have three locals I can hear plainly from this speaker, one of which I can hear from across the room when the apartment is quiet.