  We study tilting for the heart A of the canonical t-structure of the
finite-dimensional derived category of the Ginzburg algebra for a quiver with
potential (Q,W). We give conditions on that the stable objects for a central
charge on A define a sequence of simple tilts from A to A[-1]. On that
conditions the refined Donaldson-Thomas invariant associated to (Q,W) is
independent of the chosen central charge.
