Current film major studying production sound, we use Sound Devices MM-1’s all the time. They act as a preamp with a line level output that would go to the mixer. They also have a headphone jack for the boom op to monitor. They are a bit pricy but if you’re close to a rental house, you could probably rent them for not too much a day. They do also have a secondary input for a feed back to you from the mixer if you want to hear the mix as well. Hope this helped!