Shellie... I'd try your two best interconnects and your speaker cables first. So if all you have are source to pre and pre to amp then do those.... If you have multiple sources then try either the one you listen to the most... or the one with the better cable (say if one has an Apex or reference and the other has accelerator.... put it on the higher end cable).
That's where I'd start anyways :)
That's where I'd start anyways :)