In Kay's Chillington studio, as stated by mix engineer Rick Pope in this December 2000 Sound On Sound interview transcribed in the official Jamiroquai website forums.
One vital component of that list is the vintage AKG C12 valve microphone Pope recently managed to track down. "It's the perfect vocal microphone for Jay and he loves it," Pope explains. "When we were building the studio Jay was really keen to experiment and wanted to demo as many microphones as possible. I had a rack of them set up, all sorts of different mics, and he tried them all. The one that sounded like a million dollars was the AKG valve C12. We tried the cheaper, reissued version but it didn't have the same quality, so we set about finding an original. I've just managed to track one down and it took ages, eight months, to be precise. I finally got it through Crystal Pro Audio, a company run by Pete Brotzman who I used to work with at Britannia Row. It was a hassle, but it was worth the effort because it will last Jay for his entire career."