Pop mashina's debut album "Kiselina" (Eng. "Acid") belongs to the category of long-forgotten, rare gems of Yugoslav rock scene. Recorded and released in late 1973, at the dawn of rock album discography in the former Yugoslavia, the band gained recognition as a pioneering heavy "acid" rock trio influenced by both British blues-based hard rock and early progressive rock. It was the second full-fledged rock album issued by Belgrade-based PGP RTB label (the first was phenomenal Korni grupa's self-titled debut of 1972), which contained none of the then dominant vocal/orchestral pop sound of light jazzy/ Schlager/San Remo mainstream crooner music in Yugoslavia (generally known as "zabavna muzika", literally: "entertainment/good time music"). Instead, it was a mind-blowing attack to the record industry too.