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!
24 thoughts on “XLR Mic Mute Switch with LEDs – Proof of Concept”
Hi do you have the schematics?
Hello Hollis, I just got a headset and a Rolls, and would also be very interested to receive the schematic at your earliest convenience! Thanks, Kenny
Well my goodness, Hollis seems to have left the building……
Sorry about that–I’ve been busy with family stuff. I’m reworking the schematic because, although it works perfectly as a mute, there’s a possibility for power spikes to knock out the LEDs.
Curious if you’ve had a chance to get back to this. It’s exactly what I’m going to need for the pulpit Mic at church. Right now it’s running through a pgx1 body pack, so can use mute switch on that, but as soon as I get some hardlines up front it’ll be phantom powered. Anyway if you could send what you have I could maybe help tweak it
Very cool !
Hope the project is going on.
Thanks Hollis, just seeing this now :-O, but I also hope the project comes to fruition sometime this year. Got the Rolls with my DPA 4088 headset- all works fine, sure would be nice to have visual guidance.
would also be very interested in the the schematic.
im trying to make the same thing
I have done something very similar, but instead of relying on phantom power from the mixer, I simply used a wall wart, 9-12 volt, DC to power the LED’s. Use a double throw switch, one side shorts the mic hot to ground, the other side closes (or opens) the circuit for the LED’s. (Open or close the LED circuit depending on if you want the LED to be lit, or off when the mic is shorted to ground. I usually use green LED’s, on, if the mic is not shorted, and working, or red LED’s, on , when the mic is shorted to ground, ie “off”.
Very simple and cheap to build, no pops or added noise if you build it in a metal box and connect the box to ground.
Amigo vc tem o esquema do seu projeto ou canal no YouTube ¿
I also have some Mic mute boxes that I need to add a LED being powered from the 48V phantom power supply.
I can manage to do that but I always have a click sound when switching.
Do you have any clicks in your unit? could you please post the schematic of the circuit you used?
Thank you so much
Amigo vc tem o esquema para compartilhar com nós .
could you please share the schematic?
Thank you so much
Hollis, any update or schematics? Thanks.
Found Bob Stadtherr’s mic mute switch circuit he posted years ago. I built one. Works perfectly. It’s not on Crown’s site anymore but can be found here https://web.archive.org/web/20120510065956/http://crownaudio.com/mic_web/popless.htm
Hi Frank, thanks for the link but that is not the same thing as this project here.
In that one the LEDs are fed from a 9V battery.
In this project, at least what the author said was that LEDs are powered through the +48v phantom power.
There are a number of us that would still be interested in the schematic for this project and possibly a short build video pointing out where you tapped the MS111 circuit board. Thank you in advance for any assistance you can provide.
:'( I have no hope !
Happy New Year, Hollis! Like many others before me, I search for the coveted schematic on this!
Hi there. Also waiting for the schems. Thanks to you and Frank who give a track to follow.
Any idea on when your schematic will be posted? I built a simple noiseless mute switch for my condenser microphone. When i introduce an LED indicator using phantom power on audio pins 2&3, popping is heard when the mute switch is activated. I’m trying to find a way to isolate the LED power of the circuit from the audio to prevent popping when i mute the microphone.
Anybody heard from Hollis yet ?? We “ALL” are definitely waiting….waiting ….waiting for even a rough Schems… anything , anything, anything, PLEASE Hollis , any help you could help us get the “Green LED” mod going on this Rolls Mic Mute unit , PLEASE…..
(And All the kids playing in the Little League World Series EVERT YEAR are begging and waiting for this Schematic !!! NO MORE Pop on the Announcers Mic ! PLEASE HELP US ? )