There's a short story in one of my encyclopedias titled "Waiting For Dizzy" involving Art Farmer, Phil Woods, and Benny Golson, waiting for Dizzy, at Rudy Van Gelders studio, by Gene Lees.
Everyone who had ever recorded there knew Rudy's quirks, and one of them was never touch the equipment. Art Farmer told a story about Jim Hall and Red Mitchell at the studio to do a duo recording. They talked about the sound they wanted with Rudy in the control room, and Red said "You know Rudy, maybe if we just put a little more of this in there" and he touched one of the faders. Rudy said, "That's it. You don't owe me anything. Just pack up and get out"
Although Red went to high school with Rudy, don't touch the equipment still applied. That shows just how meticulous Rudy was about his recording equipment, and that also illustrates why he got such high quality recordings.