Bob,
How loud is your dehumidifier and how deaf are you?
I know I could hear the dehumidifier with the mics I have.
If those are your conditions, consider a K&K pickup system. I highly recommend the
Pure Mini. I have it in my Martin. It's not as good as a great mic, but it's better than a bad mic. No battery. No controls. Straight out at the strap button jack.
Here's what it sounds like on my D28s Martin?
It does get a little clacky if I flat pick, but I like it a lot for finger style.
Regards,
Ty Ford