I've repeated it many times: in the quest for endgame transparency, complete DAC isolation is required ...as close to 100% as possible. A responsive amplifier and linear full range transducer (speakers, headphones) is important, but to induce reality creation, its the DAC that plays the larger role. Incremental isolation improvements are always good, however, I have noted a dramatic inflection point when going to extremes. This is the amazing nature of D/A conversion in the small signal domain: there appears to be no limit to our ear/brain sensitivity.
AudioWise recently added 'Extreme' variants to RF-STOP AC and DC filters. These utilize series LRC filters or skin effect filters to further attenuate RF noise. A new product (Sept 2023) is the RF-STOP 'Extreme' Signal Filter which is applied at the output of a DAC to prevent ingress of downstream RF noise. This product is based on skin effect filters for 100% lossless filtering. The diagram below indicates all the myriad ways that RF noise enters a DAC through its output and how RF-STOP 'Extreme' Signal Filter can help.