If I understand you correctly, your DAC has only unbalanced RCA ouputs? If your DAC does not have truly balanced outputs then there wouldn't be any benefit to connecting to the balanced XLR inputs on your McIntosh amp.
The real benefits of balanced really only happen when both components being connected with XLR cables have balanced differential circuitry.
The real benefits of balanced really only happen when both components being connected with XLR cables have balanced differential circuitry.