Have you tried discrete opamps in your minimax? Since you like a meaty/rich sound I would suggest trying Burson opamps. It will cost you about $200 but IMO greatly improves on the stock sound.
Of the two other DACS you mentioned, the Metrum NOS Dac has received a lot of accolades from board members and the price is particularly favorable now given the $/Euro conversion rate.
Of the two other DACS you mentioned, the Metrum NOS Dac has received a lot of accolades from board members and the price is particularly favorable now given the $/Euro conversion rate.