Steve, here’s info about compression that you might want to consider:
You probably know that compression is designed to act like an automatic volume control to even out a signal’s peaks. You may also know that the faster the attack of the compressor, the more it grabs the beginning of the note and gives you the “boink” sound.
A humbucker delivers a hotter signal to the pedals or amps down the line. So in an attempt to control that note, at the same settings as for your single coil guitars, the compressor is going to grab onto it in an attempt to control the volume.
But the interesting thing is that a humbucker is less “peaky” than a single coil pickup. The dynamic range is different. It tends to be more even than a single coil. So you if you need the compressor at all, you certainly don’t need the compressor to grab the note as quickly as with a single coil, and you don’t need to crush it as hard to control the peaks and valleys of the volume.
You want the compressor to be less “grabby” with Humbucker, for the most part (though I suppose some folks want the boink tone, I dunno).
So you have two choices: leave the compressor set where you usually like it and turn down the guitar’s volume control, or set the compressor for a higher threshold (the volume level where the compressor “grabs” the note), a slower attack, and a lower compression ratio.
I only use a compressor with humbuckers when I want to do funky chording. Other than that, I leave it off.
You don’t really need it with most humbucker guitars unless you’re running very clean with a lot of volume and are having trouble with evenness, say, strumming the notes in a chord.