I watched Danny Ritchie’s (GR Research) video about his speaker cable kit. He uses ESR paper on the ends. He says it’s important to use just enough or SQ will falter.
I have some ESR 1" tape. I wrapped each end of my DIY PC feeding my Hydra 8, one turn, around the connector.. Instantly, noise level dropped.
Will most likely wrap all cables in my system. I can imagine taping the inside of all my electrical outlet boxes.