Cream butter. Gradually add sugar and beat until light and fluffy. Add eggs, one at a time, beating well after each addition. Sift flour with baking soda; add alternately, with sour cream, beginning and ending with flour. Add vanilla and beat on low for 2 minutes. Pour into greased and floured tube pan. Bake 1 hour and 20 minutes or until a wooden pick inserted in center comes out clean. Cool in pan on a wire rack 10 minutes. Remove cake from pan and cool completely on wire rack.