I play music on stage, and that usually means using amplification (PA) systems. The bands I play with (Frost and Fire, The Turning Stile+, and others) typically have a bunch of musicians playing a host of instruments, each with their own microphones. Consequently, we need a lot of mic mute switches. The enemy of sound is noise. The more open microphones you have on stage, the higher the noise floor gets, which is bad–so you need to be able to turn off mics when they’re not in use.
Several years ago, I bought some Rolls MS111 mic switches for this purpose, and they’ve been great–with one gripe: it’s pretty hard to see whether the mic is muted or not. You’re basically looking at a band of metal 1mm wide from about 7 feet away trying to see whether it’s 1mm or 2mm tall right now. Hard. I’ve wanted a mute switch with an LED status indicator for a while now.
The easy way to do this is to add a battery to the box, wire it into the unused side of the pushbutton switch, and use that to power the LEDs. Problem is, that would require carrying extra batteries (heavy and wasteful), modifying the case to be able to hold a 9v battery (impossible in this case), and, worst of all… knowing that the solution was inelegant.
I wanted the LEDs to be powered through the +48v phantom power that’s provided by the sound board.
I’ll detail how I did this in a future post (and provide the circuit schematic). I’ve had a lot of fun and a lot of frustration trying to figure this out, and I want to make it easier for future tinkerers. But for now, I’m typing this up and getting it out the door before I head out for a gig–and we’ll see how the mute switch does in the real world! There’s a video proof of concept at the end of the article.
- Rolls MS111 latching mic mute switch
- 5mm RGB common-cathode LED, through-hole
- 2x 20kΩ metal film resistors, 1/4 watt, 1% tolerance or better
- 470 µF electrolytic capacitor rated for 50v or higher
- trim potentiometer (I used a 10kΩ pot, but the value is not critical)
- assorted electronics tools (soldering iron, wire strippers, multimeter, precision wire cutters, etc.)
- drill bit for drilling steel (5mm would be ideal, but I only had SAE drills and my local stores did too, so I used a 3/16″ / 4.76mm drill bit instead)
Here’s a quick demo! Sorry for the camera shake–it was late and I was too tired to find the tripod).
Thanks for watching! I’ll post the schematic and further discussion soon. If you enjoyed this, please subscribe and give the video a thumbs-up!