Sure, there are tons of DACs out there. Prices range from probably < $100 to $10,000+++. What's your budget?

If you buy a nice one, you may want to use it instead of the 990's DACs. I recently auditioned the Benchmark DAC1, and found it noticably better than the 990's DACs, especially in the bass and soundstage areas. Price on that unit is $1000.