Bread-Bakers v096.n052.5

Hi,
  Thirteen years ago I visited San Francisco and bought a loaf of fresh
sourdough bread. It was one of the most delicious breads I have ever eaten.
Since then I have tried to make it using starter from yeast, and a
commercial (dried) starter from a company in Frisco. Unfortunately I have
never been able to come close to the original product. Can anyone help me?
  Leonard Stein.