The exact origins of the bootlegged Beatles recordings known as Dr. Ebbetts are unknown. One version says that Dr. Ebbetts is a combination of unofficial high-quality Mobile Security discs that were sold in the US and then throughout Europe, as well as a new release (of German or more likely Dutch origin) with CD reproductions of American releases of Beatles discs.
Whether this is true or not, these recordings are the closest in quality to the original vinyl discs.