Oh, the DIP definitely improved the sound indeed. Not something you have strain to hear either. Blacker background, improved resolution and detail, better bass definition, lot's of improvement. It reduces jitter. I have the latest DIP, but not the upsampling version, I believe it's called the DIP 24/96. I got mine used off Audiogon where there seems to be a number of them for sale often. I believe you can buy straight from monarchyaudio.com or Audio Advisor used to sell them - it might just be the upsampling version they carry now.
The sound of the dAck! does grow on you. People ask how it sounds and sometimes it's hard to describe and really that's a good thing. It doesn't sound warm really, doesn't have a plump midrange with a mellow top end and a warm bass region. Doesn't sound bright, totally lacks harshness and digital edge. It's perplexing to people who prefer one of those two signatures, especially the ones who want shimmering, stand-out highs and forced detail. The dAck! just simply sounds about right, that's the best way I can describe it, sounds like music. Not lacking, not overdone, just excellent reproduction.
