I have an electret mic on a wireless beltpack for a football referee. What would be the best way to eliminate the popping when he turns the mic on and off? I've tried a couple of various caps across the high side of the mic to grd and it made no noticeable difference. The mic only uses two cables to the transmitter, pin 1 signal in, pin 3 ground. Wired weird I know, but when I put the switch in series with the high side, pin 1, it does break the signal. I am carrying the ground through to the output side, to the transmitter, and only breaking the high side, not gnd.
I'm using a DPST switch. It also uses a mini XLR, TA3F.
Thanks for your help.

 

Since thesystem is wireless, it also includes he transmitter.
So my suggestion is do not switch the microphon on and off, but rather the transmitter. THAT will solve the problem.e

 

Even when you break only the signal line, the electret capsule is powered by a bias voltage (often 2–10 V through a resistor). When you suddenly connect or disconnect that bias line:

Capacitors in the mic preamp see a step change in voltage.
The sudden current causes a voltage spike on the signal line.
The preamp amplifies it — that’s your audible “pop”.

A simple series cap to ground usually won’t help, because the step is being applied right across the preamp input.

 

The comment in post #2 totally ignores my suggestion. ANY change in the microphone signal path will be amplified as much as the microphone audio signal. THAT is the reason that I suggest hat instead, switch the transmitter power off and on. Most wireless microphone receivers have a squelch scheme that mutes the audio output when it does not sense any signal.
AND, switching the power off and on does not require adding any connection wires to that sensitive low-level microphone signal circuit.

 

Even when you break only the signal line, the electret capsule is powered by a bias voltage (often 2–10 V through a resistor). When you suddenly connect or disconnect that bias line:

Capacitors in the mic preamp see a step change in voltage.
The sudden current causes a voltage spike on the signal line.
The preamp amplifies it — that’s your audible “pop”.

A simple series cap to ground usually won’t help, because the step is being applied right across the preamp input.

Do you have a recommendation?

 

The comment in post #2 totally ignores my suggestion. ANY change in the microphone signal path will be amplified as much as the microphone audio signal. THAT is the reason that I suggest hat instead, switch the transmitter power off and on. Most wireless microphone receivers have a squelch scheme that mutes the audio output when it does not sense any signal.
AND, switching the power off and on does not require adding any connection wires to that sensitive low-level microphone signal circuit.

Unfortunately that would not be practical. The transmitter is behind the ref on his belt. There is no way to power it on and off. Besides, the few seconds for the receiver to lock on to the transmitter would be to long. Ref wants to flip a switch,make the call, and move on.

 

Where would the microphone switch be located?? Besides that, there is no reason at all that the power switch for the transmitter will need to be at the transmitter.
BUT you are correct about the time it would take.
So the transmitter must be transmitting the whole time. Effective but not efficient!. How about a larger capacitor across the microphone THAT IS DISCONNECTED when the ref pushes the button. That cap would stay charged, so there would be no voltage change when it was disconnected. And in the short time the REF is talking it will not lose much charge if it is a good capacitor, perhaps about 0.47 mFD? Not a disc type, but a polyester or maybe a mylar cap. One rated at least 100 volts, 200 volts would be better. Easy enough to try: Just connect it across the mic and see how much audio gets thru..Probably not much.

 

Where would the microphone switch be located?? Besides that, there is no reason at all that the power switch for the transmitter will need to be at the transmitter.
BUT you are correct about the time it would take.
So the transmitter must be transmitting the whole time. Effective but not efficient!. How about a larger capacitor across the microphone THAT IS DISCONNECTED when the ref pushes the button. That cap would stay charged, so there would be no voltage change when it was disconnected. And in the short time the REF is talking it will not lose much charge if it is a good capacitor, perhaps about 0.47 mFD? Not a disc type, but a polyester or maybe a mylar cap. One rated at least 100 volts, 200 volts would be better. Easy enough to try: Just connect it across the mic and see how much audio gets thru..Probably not much.

 

The switch is on the side of the ref, usually the right side mounted on his belt. It's about a foot from the xmtr.
I'll try a higher voltage cap, the ones I've tried, the voltage was rated much lower. I'm thinking that voltage from the xmtr that powers the electret mic may have to go to gnd through a 10kor larger resistor.or something like that. I'll give it a shot
Thanks

 

Did you understand that the purpose of the capacitor that I suggested was to functionally provide an AC voltage shorted condition to prevent any audio signal to the transmitter until the switch is operated to open. This is a similar function to the switch often found on dynamic microphones. That switch directly short circuits the dynamic element in those microphones.

 

Did you understand that the purpose of the capacitor that I suggested was to functionally provide an AC voltage shorted condition to prevent any audio signal to the transmitter until the switch is operated to open. This is a similar function to the switch often found on dynamic microphones. That switch directly short circuits the dynamic element in those microphones.

Yes, got it