I think the Vimak DS-1800Mk2 dac still holds up well even today. It is the one of the best Delta Sigma dacs ever made & was designed as an incredibly complex and heavy, all-discrete Delta Sigma architecture designed by the company which invented the Delta Sigma converter, as opposed to the current crop of miniaturized Delta Sigma chips. It was really a sight to behold, wrapped in a thick, heavy copper-plated aluminium chassis with copper-clad C-core transformers in a separate shielded compartment. It was also known to have expensive taste in transports ;) You can see photos of the Mk1 version here.
