Do you have any old 12v laptop transformers lying around? They are generally much better quality lower ripple items than the cheap ebay item you linked. Alternatively buy a decent one from maplin and if it still causes similar issues, take it back and swap for another... and so on.. until you find one that works for you. They aren't the cheapest I know but they will take returns (avoids postage fees) which will work out cheaper in the long run.
6/25/15 at 3:45pm