Hi Steve
The 4066 is a bit old but not obsolete.(my new 20 inches flat screen JVC color TV receicer still uses the 4066 in it’s AV switching circuit) besides it’s NOT digital it’s an analog voltage controlled bilateral switch.Any how if Gulmann worries about his audio quality then why the switched relay attenuator array with a sorry 16 steps what’s wrong with motorized pot ? with the three stage coax he can build the famous tee attenuator and have one left for his ADC to read the wipers psition and display them to his heart’s content. Oh don’t worry about noise they used dc motor for spindle drive of CD readers
Best regards
Khanh
PS : my family name is Vu I’m a Vietnamese and in Viet Nam we put first name last and last name first!