In the case of your example with the copper coupler, I hear no difference. But I have dc charged cables. Certainly the are other examples of tweaks giving very modest or no improvements and even ones that at first I think are improvements only to change my mind. That is all part of the quest. I have tried other tweaks that give great improvements in some instances and great harm in others. An example of this is the Acoustic Revive QR-8 little quartz points.
Your own ears will have to be the judge. As the old warning goes YMMV.
Your own ears will have to be the judge. As the old warning goes YMMV.