Good question. The Brooklyn DAC+ has a dedicated phono board and ESS Sabre 9028 chip set, while the Manhattan II has a redesigned main board fitted with ESS Sabre 9038 chip set. I presume the Manhattan II likely has better SQ due to the redesigned main board and Sabre 9038 chip set. The optional phono board and the optional boards are likely higher quality boards, too, which likely can only be used with the Manhattan II DAC. Input and output functionality appears enhanced on the Manhattan II relative to the Brooklyn DAC+.
Oh, and then there is the difference in weight (suggesting a difference in chassis and power supply materials): Brooklyn DAC+ = 4 lbs: Manhattan II: 16 lbs. 4x the weight and ~$4,000 more...
Oh, and then there is the difference in weight (suggesting a difference in chassis and power supply materials): Brooklyn DAC+ = 4 lbs: Manhattan II: 16 lbs. 4x the weight and ~$4,000 more...