It doesn't require one but they seem to have better audio with an electret cartridge. The stock mics usually do a great job with Lincoln IIs. An amplified mic may just overdrive the audio without improving your sound or SSB signal strength at all. Those radios have pretty good audio for an "Export" right out of the box.I don't know if it requires an electret mic or not.
Thank youHere you go.
Just don't connect the pins 3 and 6.
Anytone At-6666 Microphone plug wiring
Well folks I had been looking for the wiring (plug) info for this radio for quite some time and finally found what I was looking for. So for those who have also wanted to use a different mic here's what I found. This info is for the the CRT SS-9900 which is simply another rebadged at-6666...www.worldwidedx.com