From the moment guitars were first electrified back in the 1930s, people have been looking to coax different sounds out of the instrument. One of the weirdest effects units was the DeArmond Trem-Trol, which was introduced in 1948. It altered the volume of an electric guitar’s signal by exposing the pin connecting the guitar to the amplifier to a brass canister filled with a special electrolytic fluid.
As you played the guitar and moved it around, the fluid washed over the pin, creating a serious of weird, watery sort of tones. There wasn’t any way to control the sounds you got out of your guitar and the canister often leaked all over the place, but it sure gave personality to your playing. If you want to hear what a DeArmond Trem-Trol sounded like, go back and listen to some early Bo Diddley records. That’s how he got that sound.