Thank you guys for the great comments!
I keep on experimenting with different variations on my personal Funk Formula, if you can call it that.
The drums absolutely were an aesthetic choice, Max, although I do usually agree with your suggestion. If you listen to most of my drum recordings, I've got individual mics on everything, all nicely gated and compressed and EQ'd. But in going for this very vintage early 70s kind of sound, I tend to use the Gabriel Roth "shitty is pretty" principle (look him up if you're interested...his articles in Tape Op changed my life).
The drums in this case were miced with an SM57 right next to my head, through a tube preamp cranked to the max, into the tape machine, at just the right level to get the tape compression just right.
I could have brightened it up once I put it in the computer, but I just kinda like the murkiness of it!
Check out Shawn Lee's "Synthesizers in Space" album for the ultimate saturated, dry, murky drum tone!