I'm a little confused with the mic situation. Is it not as simple as it was with the ps3? Currently I have my mix amp hooked up through the PS4 optical with the y adapter hooked to the mix amp and my head phones plugged into the adapter. I haven't tried to use either the dx clip on mic or modmic yet but shouldn't it work just like the ps3? It would be pretty good if it worked just by plugging into the PS4 controller itself.
*edit* EV have you tried the m100s with the boom mic? Does it work properly?
You're fine. I'm referring to my own Mixamp, which has bad feedback when I talk through the mic.
Bad for ME:
PS4 - USB/optical - Mixamp - y adapter - headphones/mic = bad mic feedback
Good for ME:
PS4 - USB (for charging only)/optical - Mixamp - headphones
PS4 Dualshock 4 - Y adapter - mic = fine