Adding Push-To-Talk (PTT) / Mute to 3-pin XLR Cable

Question

Is it possible to add PTT/Mute to a 3-pin standard terminating XLR cable (with +48V phantom power)?

In my case, I have found myself with a Astatic 40-119 microphone base with a PTT switch that "only" provides dry contact between the 4 & 5 pin of the 5-pin XLR cable. Can I use this fact to cut the power to the condenser mic, or is there some better circuity to accomplish the mute? The base works great otherwise. (There is a competing model that mutes the microphone on a standard 3-pin XLR cable that I've included the spec sheet for completeness.)

• 40-119 MIC BASE Spec Sheet

  This unit features a dependable momentary push switch that provides a dry contact between pins 4 and 5 of the cable terminating XLR connector. The switch can be configured for either "push-to-open" or "push-to-close" using the slide switch located on the underside of the base. The 40-119 base is used to control an independent device while audio signal from the mic is always on.

  Just to note: the mic does work as described. Maybe the mentioned "independent device" can mute the mic :)

• 40-116 MIC BASE Spec Sheet (don't have this, for comparison)

  The circuit contains a highly reliable switch to operate a 55dB mute which will effectively kill audio output without causing a potentially damaging phantom power "thump" when used with electret type microphones.

These questions were helpful to me but the first two are microcontroller focused. The latter 3.5mm also has a power component, I'm researching into it more.

1. Microphone mute anti-pop circuit works but still picks up a little audio
2. 5v Electret microphone to PC mute switch pop help
3. 3.5mm Push to Talk Switch

Any help would be appreciated.

Answer 1

Set the switch mode to push to open and connect it across the signal lines. (pins 2 and 3)

releasing the PTT will mute the microphone signal by shunting it.

So, connect pin 4 to pin 2 and pin 5 to pin 3

With a 20 foot cable this may not work very well. if you are allowed to modify the base make the same connection internally instead.