Hi Christopher,
If you're looking for a replacement for your Outlaw preamp/processor that has XLR inputs to match your B&K amps, there are a few options to consider.
One popular option is the Emotiva XSP-1 Gen 2, which has a fully balanced signal path with XLR inputs and outputs. It also includes a high-quality DAC with USB, optical, and coaxial inputs, so you may not need to use your SMSL DAC. Another option is the Parasound Halo P5, which also has XLR inputs and a built-in DAC with USB, optical, and coaxial inputs.
If you're looking for a more budget-friendly option, the Fosi Audio DA2120C is a 2.1 channel amplifier with USB, optical, and coaxial and RCA inputs that could work well with your B&K amps. It has a built-in DAC, but you could still use your SMSL DAC with it.
Hope this helps!