All 4 inputs on the front are the same if you use Balanced XLR inputs
The first two 1/4" TRS inputs are Hi Z for use with electric guitars
3 and 4 on front and 5 and 6 on read are 1/4" TRS line inputs
Phantom power can be turned on or off 1+2 and 3+4 (but not individually)
Individual gain controls area available for all 4 front inputs
You say you have a RODE “NKT” I assume you mean a Rode NTK -> as I can’t find the other acronym
This microphone has its own power supply from what I read on the website so doesn’t need phantom power, and indeed doesn’t recommend it though it won’t damage it).
You should be able to plug a balanced XLR (not 1/4") lead into ANY of the front 4 mic channels and so long as the gains are all the same it should be the same volume for all.
robw’s answer is pretty complete. Like he said, this mic has its own power supply. so just plug it into any of the xlr inputs in the front of the unit. Any difference in volume you’re seeing is most likely due along the gain stage ‘chain’.
Inputs 1 & 2 - Yes the XLR inputs are different to the phono. The XLR inputs are Mic/Line (balanced) the Phono input is HI Z unbalanced
Inputs 3 & 4 - No, they are both Mic/Line inputs and the phono can be unbalanced or balanced (XLR balanced of course)
Inputs 5 & 6 on the back are balanced/unbalanced line inputs. They don’t have a gain knob but you can adjust between -10 dBV and +4 dbU using the software.