I had a cheap (Harbor Freight) compressor at my old darkroom. It was on another floor and piped in by a 50 ft. hose. Had the necessary filters and nozzle, and I had it set to 40 lbs. Worked great. In my new darkroom, there was no
"other floor", so my wife gifted me with a relatively more expensive, but very quiet compressor from Rockler Woodworking. Same filter, nozzle and pressure regulator. I do have it on the other side of the room from the enlargers!