Plasma speakers are audio-modulated electric arcs.
How the hell does it work? Well it’s like this; The arc is a high frequency AC current and it constantly makes a high pitched squeal. But when the frequency is above 18kHz we humans can’t hear it because our ears fucking suck. Since it’s silent quiet we can do what we want with the arc now, and to make music we just need a little modulation.
WTF is modulation? Well if a 50kHz arc is turned on and off 2000 times a second, we hear a 2kHz tone. Now if we modulate it to the tune of music, well then music comes out. In the below circuit the 10kΩ pot controls the arc’s frequency. A lower frequency typically means higher voltage and a higher freq means more amps. The thing works best around 40-60 kHz. Also, the mosfet doesn’t have to be a 260; It can be any mosfet that can handle at least 100 volts, and more than 30 amps. It must be heatsinked very well with plenty of thermal goop though because it gets really fucking hot. You can even put the heatsink in a bucket of water, provided it doesn’t make contact with the fet’s pins.
How do I make one? I suck at soldering…
Also, too loud an audio signal will fry the chip. You’ll need a quiet signal, a really quiet one. Just turn the volume all the way down, then turn it up. When the music starts to distort that’s the max volume. The ground wire gets really hot. Hot enough to burn if it’s iron. You’ll need something with a lot of thermal mass such as a screw.