The Zoom 9030 is a rack effects unit used by Prince. It is a guitar multi-effects unit that combines an analogue preamp section with digital effects. Prince started to use the Zoom 9030 on the Diamonds and Pearls album for harmonizer effects. It became an integral part of his sound throughout the 1990s, controlled with Roland FC-100 and EV-5 controllers. Guitar World lists some of his patches, including "Twin Reverb" and "Pillow Talk". He also had various patches labelled on his FC-100 including "Twin", "Asian", "Sitar" and two wah effects - most likely 9030 effects.
It was also used on "So Far, So Pleased" on Rave Un2 The Joy Fantastic for delay and harmonizer effects. It was also used as a bass effect on the album using a patch called "slap wah". Prince used a ring modulation effect, which can be heard on Rainbow Children, One Night Alone...Live and N.E.W.S. This could have been the Zoom 9030's "Metallic" patch, combined with an EV-5 expression pedal. After the Musicology tour Prince stopped using his rack system so stopped using the Zoom 9030 live. Prince used a Digitech Whammy for pitch shifting and a Line6 MM4 for modulation effects.
Tony M also used the Zoom 9030 for guitar processing on the Diamonds and Pearls and Act & II tours. It is one of the effects listed in the December 1992 issue of Musician magazine.
[On So Far, So Pleased] I ran my guitar through a Boss Vibrato and Flanger. The octave and delay effects are from the Zoom 9030.