same user of U18 and X26 Pro, I just use LHY OCK2 instead of AfterDark. Honestly, a clock together with U18 and X26 Pro somehow produces a synergy that is well beyond the price tag of these equipment. I have compared it with R26, the R26 cannot match X26 Pro in the bass department, and with a matching clock, the R2R cannot even beat X26 Pro in the mids and airy treble. With X26 Pro alone, it will lose out to R26..... however with U18+X26 Pro+Clock, the synergy works. I played with a lot of equipment, even the more expensive Weiss 204 DAC may not beat this combo.