In 1947, when Joan Llenas was Radio Terrassa announcer speaker and also a big fan of the theater, proposed to the direction of the station to create a theater group. His idea was accepted, and soon started "Compañia de Comedias de Radio Terrassa", and on July 15th of the same year under the direction of the same Llenas, Radio Terrassa started to put on the air the play "El ladrón". Then followed "Cobardias", "El zapatero y el rey", "La puntaire", "Doña Clarines", "El genio alegre", "La enemga", "La corona d'espines", "El Nido ajeno", "Terra Baixa", "Yo acuso", "L'Hostal de la Glòria," "Amores y amoríos", "El gran galeote", among many others, both in Catalan and Spanish. The most notable success of all functions of the time is the memorable performance of "Don Juan Tenorio" by José Zorrilla in "Teatre Alegria" on October 30th, 1951, in which Llenas played Don Juan. On that day, at that stage, and attended as guests of honor actors Conrado Sanmartin and Paco Rabal, actor and radio theater from Radio Barcelona, ​​Isidro Sola, was achieved unprecedented success as a result of which Radio Theater Voices Company and components began to act in different towns and stations in the province getting a remarkable echo. Were common at that time, actors and actresses like Rosa Maria Martinez, Elsa Campoy, Maria Teresa Padrós, Julia Morales, Lidia Segués, Micaela Pedrolo, Joan Garrigó, Josep Alemany, Ramon Bravo, Lluís Jordà, Jordi Campà, Gabriel Alonso, Salvador Llach, Albert Puig and Francisco Izquierdo, who also did work as artistic director of the theater group performing in front of a theater audience, all under the direction of Llenas.
But aside from the radio drama, Joan Llenas developed other activities in front of the microphone. He was also an outstanding rhapsodist, and was editor of the Sports Department of the station. Her writing, commentary and interviews always enjoyed a good reception from the public. Among the sporting events that will be commissioned in the stand of the XXX Tour of Catalonia in 1950, and the first complete coverage of a football game that made Radio Terrassa, a decisive match between Arenas Zaragoza and Terrassa FC, in which Joan Llenas with his excited voice was transmitted waves to vibrate throughout the city and achieved a historic success.
The task of Llenas in Radio Terrassa lasted for a few decades, until the late sixties, when Joan Llenas moved to live in Barcelona, ​​where he died a few years later.