I just spend a week going back and forth with three power cords on my Rossini Apex Dac and clock. I tried a Shunyata Sigma X NR, a Transparent Opus Source, and a Nordost TYR. The rest of my system consists of a Kondo preamp, CH Precsion A1.5, Wilson W/P 50th and a Loke. The interconnects and speaker cables are current Transparent XL. I ranked the cables in this order: Opus, Sigma, Nordost. The Opus was more resolving and I felt the Sigma X may have been over dampening (if that makes sense).
This is pretty much in line with my thinking and decisions. I’ve upgraded my Transparent cables step by step though the range going from Plus via Super to Reference for both Interconnects and speaker cables. After Shunyata were established I compared their power cables against (what I thought were) my excellent PS Audio Power cables. For the Mono-Blocks, straight to the dedicated ring main, the bass response took on a different dimension. Following this revelation it wasn’t long before I went full loom Shunyata Alpha for power to all dCS and Chord boxes and (eBay supplied) Shunyata Venom for speaker power - as Ive got active hybrid electrostatic/class D driven bass woofers - Martin Logan