I like the 7 better than the 6, but its a matter of taste. The 6 does not offer DSD.
Not sure what the PCM chip is, but the DSD is Dac-chip-less. LPF only.
Tube rectified with either twin 6x5 FW rectifiers, or lately 5u4g / 274b/GZ34 class single recti.
Output tubes can be a pair of either 45 triodes/101d/2A3s. The 2A3 requires throwing a switch. infiniute fun rolling tubes here and so easy as they are exposed on top.
There are now tube rolling threads at the Circle for people who want to indulge. Lots of hunting on the Bay and here for NOS tubes to try. Debates already over what sounds best. I got my Cunninghams in anticipation!