One further update, trying on analogue output, then no need to restrict output frequency let the Explorer be a DAC then the 565 convert to 96 24 to DSP 33. Will do some subjective tests.

Any thoughts?

Main system: 271, Arcam 860, 5500, 5500HC, 8x 33s, OPPO 203, Xbox One S, AppleTV4K, Mac Mini, Sony VW760, Stewart cabaret screen, LG 850 HDR TV, Linn LP12, Itok, Klyde, SkyQ,
Broken! G68D, 598DP
System 2: 565, Marantz SR6011, HD621, 519, 5000, 5000C, Mission 770, Quad 405x2, xBox1, SkyHD, Apple TV. JVC HD950.
Panasonic BD, Toshiba HD-DVD.