San Gabriel Valley Choral Company
The San Gabriel Valley's premier choral group
Artistic Directors

Dr. Alexandra Grabarchuk

Artistic Director

Alexandra is a Ukrainian-born conductor with a PhD from the UCLA Department of Musicology. In addition to her position as Artistic Director of the SGVCC, she currently holds the position of Visiting Assistant Professor of Choral Direction & Musicology at Earlham College. She has also conducted with the Contemporary Choral Collective of Los Angeles (C3LA), and held adjunct positions at UCLA, Chaffey College, Mt. SAC, and the Claremont Consortium. As well as conducting and teaching, Alex is also a mezzo-soprano soloist with a wide variety of musical interests ranging from Renaissance polyphony to traditional Balkan singing. Her vision for the San Gabriel Valley Choral Company is built on the pillars of strong musicianship, diverse repertoire, and vibrant community. 

For more information about Dr. Grabarchuk, please visit

Dr. David Rentz
Visiting Artistic Director

David Rentz is Associate Professor of Music at Chaffey College, where he heads the choral and vocal music programs and teaches music theory. He has also taught and conducted choral ensembles at the University of Wisconsin-Madison, Yale University, and, most recently, Pomona and Scripps Colleges. He is the Music Director of the Orchestra Collective of Orange County and Co-Conductor of C3LA (Contemporary Choral Collective of Los Angeles). Dr. Rentz received his BMus summa cum laude from Washington University in Saint Louis. He earned his MM at the University of Wisconsin-Madison, and received his MMA and DMA from the Yale University School of Music.

​For more information about Dr. Rentz, please visit


Deborah DeGrado

Deborah DeGrado is pianist/accompanist for the San Gabriel Valley Choral Company and a freelance collaborative artist specializing in rehearsal accompaniment and performance, holding a Bachelor of Music degree in Applied Piano Performance form Biola University. She currently serves as accompanist for Los Osos High School, Diamond Ranch High School, Redlands High School, and Vineyard Jr. High School. In addition to her school work, Deborah performs with the Glendora High School show choirs and performs as "Pit Boss" and Musical Director for high school and college musicals. She also servesas rehearsal accompanist and instructor of "Academy Broadway Skills" for the Inland Pacific Ballet Company in Upland. She has served more than 25 years as pianist, organist and percussionist for Purpose Church in Pomona and is a piano instructor for Purpose Church School of Fine Arts. She enjoys lasting friendships made while collaborating with fine artists and numerous vocal studios and ensembles all over Southern California. Deborah lives in Pomona and enjoys traveling to visit her grandkids in Ohio and Florida.
Section Leaders

Kristina Valcarce

Diana Woolner

Soprano Section Leader

Born in Brooklyn, Ms. Valcarce learned about music from her dad, a guitar player in local rocks bands. She received her BFA in Music from the Purchase College Conservatory of Music and her MM in Voice from the MAnnes College of Music. Her first role was at the age of 21, singing Livio in Alessandro Scarlatti's opera "Eraclea." She has since performed with many orchestras and ensembles, including The Los Angeles Philharmonic, Pasadena Lyric Opera, Opera of the Foothills, Lyric Opera of Los Angeles, ProVoce, the New Valley Symphony, Saint Mark's Episcopal Church of Glendale's Canterbury Choir, the Choir of Saint James in the City, the Nachshon Minyan Choir, the Voices of Christmas, and the San Gabriel Valley Choral Company. She's also a mom and loves it, despite the fact that her school-aged daughter is her toughest critic.
Alto Section Leader

Diana seeks out high-quality, thoughtful performance opportunities--as director, composer, conductor, arranger, soloist, and more. Her roles have varied, from Choir Director at Our Lady of the Miraculous Medal in Queens, New York; on-set Music Coordinator for Steven Soderbergh's television series "The Knick;" 3rd prize winner with NYC-based ensemble GHOSTLIGHT CHORUS at the 14th International Chamber Choir Competition in Marktoberdorf, Germany; featured composer during Vassar College's ModFest; performer across the New York tri-state area, including MOMA, Symphony Space, and David H. Koch Theater at Lincoln Center; and Staff Alto in Pacific Chorale. Diana's music ranges from (but is not limited to) vocal ensemble works, electro-acoustic soundscapes, film scores, choreographed dances, and radio plays. Her music often has a magical qulity, and her vocal works are known to utilize unconventional texts. An ex-New Yorker recently transplanted to Los Angeles, Diana is an active member of the contemporary choral collective C3LA, the Alto II section leader at St. Matthew's Episcopal Church in the Pacific Palisades, and a member of ARETE', a professional ensemble of vocal artists based in Thousand Oaks.

Oscar Sebastian

Jacob Sidney

Tenor Section Leader

Oscar Sebastian has competed in numerous vocal competitions including the Western Regional Metropolitan Opera auditions. He was accepted into the highly selective gospel group “The Continental Singers” and has performed throughout the southwestern United States. Oscar was a recipient of the “Readers Digest Scholarship” while at Berkshire Preparatory School in Sheffield, Massachusetts where he was also a finalist in the “Western New England Singing Competition”. Completing Vocal Performance studies at the University of the Pacific and California State University Northridge, he embarked in his singing career becoming a member of the “Wagner Ensemble” and sang in the “Opera Orchestra of Los Angeles” in addition to singing at such local venues as the Los Angeles Music Center, the Pasadena Civic Auditorium and the Ambassador Auditorium. He was a member of the Pacific Chorale under acclaimed Artistic Director John Alexander and participated in a choral concert tour of Finland and the ex-Soviet Union performing before international dignitaries and national leaders in Helsinki, St. Petersburg, Estonia, Georgia, Kiev and Moscow. He was a premier soloist performing in an inaugural concert in Brazil where in conjunction he participated as a missionary building a church for the indigenous people of the Amazon River Valley. Oscar is presently Tenor Lead, Soloist and Choral Scholar in several churches and choral groups and performs in various concert venues throughout the greater Los Angeles area.
Bass Section Leader

Jacob Sidney originally studied classical voice before focusing on "straight" acting, but as a young man was fortunate to sing with the Tanglewood Festival Chorus (Mahler's 2nd Symphony with Seiji Ozawa) and Seattle Symphony Chorale (Carmina Burana), as well as exploring the works of Part, Durufle', Ives (with Michael Tilson Thomas), Handel, and many other great composers of choral repertoire. As a singing actor he's appeared in "The Bahavior of Broadus" at Sacred Fools, Spark's "The Seduction of Ingmar Bergman" at the Ford Amphitheatre, "The Beastly Bombing" at the Steve Allen, as well as "A Chorus Line"(Paul), "West Side Story" (Riff), and "La Boheme" (Schaunard). He has arranged and recorded vocal pieces for the stage works "The Treatment" (Theatre Movement Bazaar/Boston Court) and "King Phycus" (Hollywood Fringe), and founded the 20th Century Pop Christmas group The Sleigh Belles in 2013. He's been honored to serve as Bass Section Leader for SGVCC since 2015.