His first professional appearance was in the jazz-rock fusion band Tact (Bulgarian:Такт) with Yavor Dimitrov (piano) Miroslav Janev (bass guitar) and Evgeniy Simeonov (guitar). After the group broke up, he played in several professional bands during his secondary education. When he had barely started his higher education, Yankoulov joined the Big Band of Bulgarian National Radio, in which he played for seven years. Playing in many jazz formations, he quickly got into the swing of jazz music and became a regular performer in major jazz festivals in Varna, Apollonia, Plovdiv, Rousse and others.