Mandolin traditionally is an Italian instrument. It is also called Mandola or Mandoza. It was never there in the history of  either Carnatic classical music or Indian classical music. 

Bringing in the niceties of most difficult carnatic ragas especially ragas like Thodi, was not an easy step in the beginning as it has a gandhara situated in between two Swaras. Attaining speed with the ragas like Thodi and Kamawardhini came as tougher challenges in the beginning which started shaping out beautifully on the finger tips of Raghavendra. This consumed a decade of tiring less practices and dedication. "Playing mandolin is too volatile, if you don't practice for a week or so, the roughness on your fingers would go away and the strings will start slipping on your fingers"        says Raghavendra. "Indeed practice makes the man perfect" --- the mantra taught by his father.

Mandolin is an instrument that tempts the player to go more faster than steady and slow paces. Some ragas become too vulnerable if they are played in high speed and they certainly lose their sharp features at that speed and hence have to be played with very slow and steady pace. Regulating the speed with rhythmic beats came after a long chain of successes.

"Attaining that controlled speed for some Keerthanas was very difficult but he could do that only when he realized after a few concerts where in he overdrove the accompaniments and stopped after completely exhausting them" ---- his mother adds.

Initially start with a double string, traditional Mandolin which is unconventional and unfit for Carnatic music was very difficult to play some of the fast and melodious Ragas. He later switched over to Electric Mandolin, which has five single strings unlike the regular ones and they are single strings with three SHADJAM and two PANCHAMA.The conventional acoustic mandolin has double strings (E,A,D,G). the modified Electric Mandolin has Five string (E,A,D,G,G). the last "G" being the lower Shadjam.

"I don't know even a single fret in that instrument, and I don't know how he picked up Carnatic music on that tiny instrument. All I could do was to correct him in his Gamakas and other fingering mistakes while he played but he did the rest. It looked, he had that gift of picking up the ragas readily on that instrument as if he knew that instrument for years" -- Mother remembers the early stages of his practices on the mandolin.