PC Stereo Mic in TRS circuits

Thread Starter


Joined Aug 18, 2020
Does any have any circuits of what is sometimes a stereo mic input on a PC that I presume is L/R/Gnd on the 3.5mm jack that you.
Also on some recorders you get a similar arrangement with '3v phantom power' mics.

I presume the bias resistor and dc decoupling capacitor are not mic side but pc side (usb sound card).

I have a TS Mic and that works on a stereo card and not on a mono which makes sense as the the R from the TRS is the bias is missing or shorted now to the gnd of the sleeve.

Also on a stereo 3.5mm cable wiring up some relatively cheap electrets Taidacent 9750 to a stereo soundcard works quite well.
Doing the same with some supposedly better electrets Kingstate KEIG4537TFL-N works but wow the signal and sound is awful.

The Taidacent recommend a load resistor of approx 680 ohm with a 1.5v standard operating voltage.
The Kingstate recommend RL of 2k with same operating voltage of 1.5v

I presume the Kingstate sounds so bad due to bad impedance matching and that the RL of the sound card is to low?
That maybe a 1 to 1.5k resistor might fix?

Is it just guess work with the circuit employed with these '3v phantom power` mics that you find either as stereo configs or often with wireless transmitters.

I presume with a bit of meddling I will get these working OK but thought I would ask if anyone knows more?