Charles LOOS always appreciated horns, as would testify long collaborations with Steve HOUBEN or Ali RYERSON. Currently, he is associated with young saxophonist / clarinet player André DONNI, who he met few years back when LOOS created his group "Sweet Substitutes", a project revolving around a Dixieland repertoire, played by modern jazz musicians. When later on Loos formed his "Old Time Trio", playing revisited pieces by Jerry Roll MORTON, ELLINGTON or GERSHWIN, he naturally have chosen André DONNI as soloist - one of the rare Belgian Musicians who has completely assimilated the tradition of jazz. Recently, the duo reunited for a third common project, resulting from LOOS's desire to play old standards and the will of André DONNI to play Charles' compositions. The project has yielded a CD album "Unknown Mallow", published by Igloo end '95. With one exception, a piece by Billy STRAYHORN, all pieces are original, but re-created in a Blue Note approach of the years 50-60.

In December 2002, the band, with this time André VAN LINT on double bass and Luc VANDEN BOSCH on drums, presented a second album, titled "Just One of those Things"

Charles LOOS is also available in trio, solo, with the SWEET SUBSTITUTES, and participates in the band PARFUM LATIN etc...