To my surprise attaching an unused pair of Mapleshade ribbon speaker cables to the Amps neg. terminals and having them unattached lying on the floor has changed our sound. More clarity without loss of tonality. Improved bass much tighter and dynamic. Go figure. Cymbals had more air and decay of harmonics as well.
Adding those little pigtails thingies to the neg. posts of the speakers as Elizabeth [ Audiocircle ] suggested really blew my mind. Check it out and hear for yourself. Using both is the key.
A worthwhile experiment IMO.
charles