シュトゥットガルト放送交響楽団
Krapp has performed throughout Europe, America and Japan as a concert organist and was worked with renowned conductors such as Rafael Kubelík, Georges Prêtre, Colin Davis, Lorin Maazel, Vladimir Fedoseyev, Horst Stein and Christoph Eschenbach. He played Bach's complete organ oeuvre several times. All 14 concerts of it in Munich were broadcast live. He also played and recorded organ concertos by Handel and his entire harpsichord works. In 1985 he performed Handel's Organ Concertos Op. 4 with the Stuttgart Radio Symphony Orchestra in collaboration with South German Radio.