Antique Sound Labs Flora EX DT is a tube preamp that uses autoformers for the volume control so it certainly can be done. I toyed with the idea of doing it as substitute for the Kozmo stepped attenuators in my Audio Note Kits Mentor L5 preamp, but instead just used the Intact Audio Elma attenuators in a simple autoformer volume control that I built.
Autoformer volume control in an active tube preamp?
Does anyone make something like this? Has anyone successfully replaced the standard volume control in an active tube pre with an autoformer, like the Elma 47 position from Dave Slagle/Intact Audio?