The cassette was produced in Poland during the communist dictatorship (imposed by the Soviet Union), so unfortunately very low quality, but basically there was nothing to choose from (only production of communist countries). Even when it was new, the quality was poor, and after over 40 years and many overwrites, it is very bad. The year 1980 is not certain - who remembers after so many years, I was a child... ;-) I know on which tape recorder it was first used and I know the approximate date of purchase of this tape recorder by my parents, hence the date (+/- 1 year).