In 1985, Juan met renowned guitarist Paul Gilbert and the two started the ground-breaking metal outfit, Racer X. The band released two studio albums (1986’s Street Lethal and 1987’s Second Heat, both on Shrapnel Records), both of which showcased the band’s incredible speed, dexterity and skill in what many have dubbed “shred metal.” After releasing couple of live records, the members of Racer X went their separate ways in 1988, but reformed eleven years later, recording Technical Difficulties (Universal) and touring throughout Japan where the album reached gold status. Most recently, in 2009, the band did a one-off performance at Anaheim’s annual National Association of Music Merchants (NAMM) convention.
Post-Racer X, Juan formed another Los-Angeles-based rock band, The Scream, which produced two albums (1991’s Let It Scream and 1993’s Take It To The Next Level) on Hollywood records before disbanding. He then moved onto Pet, a group founded by soundtrack composer Tyler Bates (300, The Day The Earth Stood Still, Watchmen) and vocalist Lisa Papineau. Singer Tori Amos had signed them to her Igloo/ Atlantic Records imprint and released the band’s self-titled debut album. In 1999, Juan and Lisa formed Big Sir out of the ashes of Pet and incorporated contributions from Tim Commerford (Rage Against the Machine) and Bruce Bouillet (Racer X) in early recordings. The group’s signature sound came from Juan and Lisa’s shared love of hip hop, Tortoise’s two-bass attack, Jaco Pastorius’s work with Joni Mitchell, and an affinity for cult artists like Dalis Car and Thomas Dolby. Big Sir released their self-titled debut album on Mootron Records in 2000 and the subsequent remix collection, Now That’s What I Call Big Sir (Mootron), was released the following year. 2006 saw the band released their third album, Und Die Scheiße Ändert Sich Immer (GSL), a more collaborative effort featuring contributions from keyboardist Money Mark (Beastie Boys), bassist Jonathan Hischke (Broken Bells, Hella) and members of The Mars Volta. Juan performed with Big Sir at the 2010 Bass Player Live/Hall of Fame concert which saw the induction of Alphonso Johnson and Bootsy Collins. A fourth album, Before Gardens After Gardens (Sargent House) was released to critical acclaim in 2012. The band is currently working on a digital hardcore album which is slated to be released later this year.
In addition to Big Sir, the 90’s saw Juan in several other projects- most notably Silverlake club staples Distortion Felix, lead by veteran recording engineer Manny Nieto (The Breeders, 400 Blows). Their debut album, 1999’s Record, was released on Girls Against Boy’s bassist Johnny Temple’s Akashic Records. The band’s follow-up, I’m An Athlete, was recorded by Steve Albini and released by seminal indie rock label, Alias Records. Distortion Felix toured with the likes of Girls Against Boys, Buffalo Daughter, Shellac and Fugazi; in 2009 they performed at the Breeders-curated All Tomorrow’s Parties festival in the UK. When not working with his other bands, Juan was also a member of the now defunct Dr. Octagon band, featuring rapper Kool Keith, dj crew The Invisibl Skratch Piklz and producer Dan “The Automator” Nakamura.
After returning to college and receiving his Bachelor of Arts degree in English literature, Juan was approached in 2003 by Omar Rodriguez Lopez of The Mars Volta to be the touring bassist for the run of the band’s debut album, De-Loused in the Comatorium. After a successful, year-long tour, Juan became a permanent member of the group and went on to record The Mars Volta’s landmark second album, Frances the Mute (Universal). It was this album that inspired Bass Player Magazine’s editors to put Juan on the cover of their March, 2005 issue. The band released a live album and two studio albums in the next three years, including the critically acclaimed 2008 album The Bedlam in Goliath, featuring the track, Wax Simulacra, for which the band won the Grammy Award for Best Hard Rock Performance in 2009. Later that year, the band signed to Warner Brothers Records and released their fifth and sixth studio albums, Octahedron and Noctourniquet. In addition to his work with The Mars Volta, Juan frequently contributed to Rodriguez Lopez’s countless solo releases and toured extensively with the Omar Rodriguez Lopez Group.
As a solo artist, Juan initiated a project called Vato Negro in 1999 and the group released its debut album, Bumpers (N2O Records), in 2008. The following year, the group made its live debut at Bass Player Magazine’s Bass Player Live! concert, which doubled as the Hall of Fame induction for bassists Charlie Haden and Rocco Prestia. Though initially a drum and bass duo comprised of only Juan and drummer Matt Sherrod (Beck, Crowded House), Vato Negro evolved into a trio, and counted Rodriguez Lopez and drummer Deantoni Parks (The Mars Volta, Kudu) among its ranks. This dynamic lineup debuted at the 2010 Fuji Rock Festival in Japan and played to a crowd of over 20,000 enthusiastic fans. Vato Negro has become a project made of a constantly rotating lineup; new music is on the horizon for late 2013.
In 2013 it was announced that former The Mars Volta frontman Cedric Bixler Zavala would start his own project- ZAVALAZ- with Juan on bass, Dan Elkin (Hella, Broken Bells) on guitar and Gregory Rogove (Devendra Banhart) on drums. ZAVALAZ is working on their debut album.