@letch I'd be interested to hear about your experiments. Perhaps start a thread called "Tube-rolling with the MHDT Orchid DAC"? It's a popular enough product that we might find some interesting contributions which detail how different tubes and associated equipment combine to create different sonic outcomes.
One person relayed the following to me:
Brighter: GE 5670 5-star (stock tube); a good tube.
Softer: Tesla 6cc42; great midpoint tube.
Extra soft: Western Electric 2C51
One person relayed the following to me:
Brighter: GE 5670 5-star (stock tube); a good tube.
Softer: Tesla 6cc42; great midpoint tube.
Extra soft: Western Electric 2C51