When the Paradigm Trio gives its first concert of the new season Monday, it will be without pianist Jed Moss.

Together with violinist Kelly Parkinson and violist Joel Rosenberg, Moss is one of the group's founding members. But besides playing with his colleagues in the trio, Moss is also the keyboard player for the pop group Air Supply, whose international touring schedule often makes it difficult for him to join the trio in Salt Lake City.

This time, instead of working around Air Supply's calendar, Rosenberg and Parkinson decided to go ahead with their concert as originally planned. Replacing Moss will be pianist Barbara Allen. "Kelly and I are glad she's with us," Rosenberg said. "We're gad to collaborate with her."

Rosenberg said that he and Parkinson were first introduced to Allen, who is on the faculty at Brigham Young University, shortly before they began rehearsals for Monday's concert. "We met her right before we started rehearsing. She's a wonderful pianist."

But he was careful to point out that Allen isn't replacing Moss permanently. "Jed will be joining us for our concerts in January."

For Monday's concert, the trio has selected two of the major works in the piano-trio literature, Beethoven's Trio in B flat major, op. 97 ("Archduke"), and Mendelssohn's Trio No. 1 in D minor, op. 49.

The Paradigm Trio has played these works in concerts in the past, but Rosenberg said they never get tired of them. "The 'Archduke' occupies the highest position of distinction in the repertoire." Among the most expansive and largest works written for the medium, the work achieves symphonic proportions. "It's actually a symphony scored for trio," he said.

Mendelssohn's D minor Trio is no less imposing. "It is on the same level as the 'Archduke,' " Rosenberg said. "It has occupied a prominent place in the trio repertoire, along with the Brahms B major (op. 8) and the two by Schubert (D. 898 and D. 929)."

Contemporaries such as Schumann had a high regard for the work. "Schumann said that, based on the D minor Trio, Mendelssohn could be called the Mozart of the 19th century."

Not unlike Brahms, who was notorious for continually revising his works before allowing them to be published — often destroying manuscripts because they didn't meet the high standards of self criticism he had set for himself — Mendelssohn also often reworked his scores. "He worked on his 'Italian' Symphony (No. 4 in A major) for 14 years after it was first performed," Rosenberg said. "It wasn't finally published until after his death."