Alderete was born in
Los Angeles,
California the fourth of five children. Son of the late civil rights activist Angel Manuel Alderete, he was exposed to
jazz music on a weekly basis by his father, who often played it around the Alderete household. Juan decided to pick up the bass after he and his friends decided to start a band. Other early influences included his brother's
progressive rock albums, which included bands such as
Yes,
Rush,
King Crimson, etc. He started learning the basics of the bass guitar when he was 16, and was influenced by such players as
Jaco Pastorius,
Geddy Lee, and
Stanley Clarke. Some of his other influences include
Jamaladeen Tacuma and
John Entwistle, the bass player for the Who. His fascination with the bass guitar revolved around it being a somewhat "underappreciated" instrument at the time. Alderete enrolled in
Musicians Institute in
Hollywood (Los Angeles, CA). He enjoyed his time in the school, explaining that he was able to learn techniques and styles that he had never even considered prior to his enrollment. Alderete and fellow student
Paul Gilbert started their musical relationship during an audition that Alderete held to find a drummer. Alderete showed up at the audition, bringing a Musician's Institute student and drum-playing friend named Bill Lescohier. Although Lescohier was turned down for the part, Gilbert was impressed with Alderete's bass playing; the two quickly sought to form a
speed metal band that would incorporate Gilbert's advanced
neoclassical metal guitar technique with Alderete's solid bass lines. To complete the band,
Harry Gschoesser joined to fill the drummer position, and
Jeff Martin became the vocalist; the group named themselves
Racer X (a title that Lescohier had suggested). With this lineup, the band released their debut album,
Street Lethal, in 1986. Alderete has been recording with Racer X ever since (note: there was a ten-year hiatus starting from 1989), and their latest album was released in 2002, titled
Getting Heavier. Alderete is credited as John Alderete on all Racer X albums. However, four years after the creation of the band, Gilbert left Racer X to form the band
Mr. Big. The remaining members of Racer X decided to stay active in music, although they went their separate ways. For the next ten years, Alderete would be involved in several different bands (including The Scream, DC-10,
Big Sir, and Distortion Felix) as well as becoming an instructor at Musicians Institute. Not long after, he released his first instructional video on bass techniques and
modulation. Although
Extreme Volume II: Live was released in 1992, Racer X was not actually reunited. That year, Paul Gilbert was touring with Mr. Big, and Alderete was recording with a
hard rock band called
The Scream. In actuality, the album was just a compilation of songs that were recorded in concerts before the hiatus. However, around 1999, Alderete got a telephone call from Paul Gilbert, who asked if there was any possibility of recording another Racer X album. Juan agreed, and Racer X reunited to record
Technical Difficulties, which features new material as well as older songs that were never recorded. In 2003, while working as a radio producer, Alderete received a call from
Omar Rodríguez-López of
The Mars Volta while on their European tour with an offer to audition for the band: He went on to record
Frances The Mute with them in 2004, and has played bass on every Mars Volta album since, as well as a number of solo albums by Omar Rodríguez-López. Since joining the band, he has played at Madison Square Garden and was featured on the front cover of the March 2005 issue of Bass Player Magazine. Aside from The Mars Volta, Alderete has been invested in his own musical projects.
Big Sir is a group composed of Juan and singer
Lisa Papineau that has released four albums. Vato Negro is a group with a revolving door of musicians; originally a duo of Alderete and drummer
Matt Sherrod, it has since featured
Deantoni Parks, Omar Rodriguez-López, and
Jon Theodore in various lineups. Alderete has played shows with both groups in 2010, in California and Fuji Rock Festival in Japan. In addition, Alderete co-produced the film
The Sentimental Engine Slayer with Rodríguez-López and former Mars Volta bandmate
Paul Hinojos. After The Mars Volta broke up in 2013, Alderete joined vocalist Cedric-Bixler Zavala in his new band,
Zavalaz. He later became the touring bassist for
Deltron 3030 and
Juliette Lewis and the Licks. Juan also runs a website dedicated to showcasing effects pedals and other musical gear called PedalsAndEffects.com. Alderete also laid down the bass line for the late rapper and singer
Lil Peep on his 2017 single "
Benz Truck (гелик)". On November 5, 2017. Alderete filled in bass for
Marilyn Manson at the Ozzfest Meets Knotfest festival, replacing longtime bassist Jeordie White, a.k.a.
Twiggy Ramirez. He was Manson's live bass player from then until 2020 following his bicycle accident. He recorded bass tracks on the 2020 album
We Are Chaos. ==Personal life==