Described as "earth jazz alchemists" by Vortex Magazine, Jay Si Proof is a musical collective founded in 2019 by trombonist/singer Jeff Chilton in Portland, OR. Enlivened by years working as a cruise ship musician and  sideman in the diverse Portland music scene, Chilton is know for his charismatic and energetic live performances. He has performed with international bands such as The Diamonds, The Platters, and Broken Social Scene as well as countless PDX bands including Dirty Revival, Onion the Man, and the Portland Jazz Composers Ensemble. He has played at venues such as Pickathon Music Festival, The Crystal Ballroom, The Wonder Ballroom, Doug Fir, Goodfoot Lounge, Grassroots Music Festival and more.

Joining him in Jay Si Proof, on stage and in the studio, is a rotating cast of Portland scene standouts musicians including Corey Heppner, Levi Zalman (Brizzleman), JD Erickson (Legato Gusto), Zac Allen (Talking Heads Tribute LDW), and Lucas James (drummer for Curtis Delgado). Jay Si Proof's unique sound combines jam band and funk textures in the style of "Lettuce" with lyricism rooted in self empowerment, all wrapped into clean modern compositions influenced by LA's Vulpeck and Moonchild.

Jay Si Proof released the 5 track  "Closer" EP in Spring of 2021 to noteworthy praise and attention at home on Portland's KMHD Jazz Radio as well as abroad in Europe and South American playlists. They are releasing their 12 track album "Care About It" summer of 2022.