First let's not confuse caps, which simply surround the positive with the ground, with shorting plugs, which actually short the positive and ground. Cardas Caps are an example of the former and the old shorting plugs that came with Mac gear back in the day would be an example of the latter. I notice no difference with the former, but have had quite a good result from using shorting plugs, finding the overall noise architecture to be diminished and the fabric of the music to be clearer. YMMV.