Hi,
I've tried the Groneberg, Siltech and stock cable. Honestly, if there is a difference...I cannot tell. Anyway, the transformer is just for the relay and does not interfere with the signal path at all.
During the show, there was a request to switch 2 CDPs (Rega Planet and Xindak SCD2) on the Etesian. You should heard how transparent the Etesian is...the 2 CDP sounds so different. On other systems, the difference would probably be not as wide.