DDC is NOT recommended in the chain. First, jitter from the digital source such as CD player or streamer is not an issue as you think. Pick a good source to begin with. A good digital source should have jitter controlled at around 10 rms micro-second and human hearing could not discern distortion until jitters hit 10-20 rms milli-second. For music, the tolerance is even higher as 200 milli-second. Don't expect placing a DDC after a so-so source will magically fix the glitches. Second, unless the DDC is of quality, placing it in the chain will actually degrade the overall sound quality. Less is better but you definitely need a preamp.