Pre-heat oven to 350°F.
In a large bowl, cream butter and sugar until light and fluffy.
Add eggs, one at a time, beating well after each addition; beat in vanilla.
In a small bowl, combine the flour, baking powder, baking soda and salt; add to creamed mixture alternately with buttermilk, beating well after each addition.
Pour into a greased and floured 10-inch tube pan.
Place in pre-heated oven and bake until a toothpick inserted in center comes out clean; 55 to 70 minutes.
Remove from oven; cool 10 minutes.
Run a knife around edges and center tube of pan.
Invert cake onto a wire rack over waxed paper.