i have 3 ref 1000m amps across my front in a HT configuration. I have used Crystal Cable, Siltech and now Purist Audio Designs (Neptune). I can def attest to a change in the tonality as i moved across the power cords.
it may be that the power cords you have chosen actually sound similar and therefore you didnt hear much difference.
it may be that the power cords you have chosen actually sound similar and therefore you didnt hear much difference.