Nice solution to the docking problem.LOL, I think I mean for a long time. I've tried all manner of portable configuration since I fly about 75-100K miles a year. I am done with stacking and I am done with full-size headphones for travel. I've gone separate discrete desktop setup for home. For my office I use the SP1000 with CDM and even there, I don't think I need CDM, but since I already have it, why not. Plus I managed to but a nice desktop stacking design together pictured below. Not pictured - all the back cables for CDM and the charging cable connected to the CDM. The balanced to balanced cable is a custom made one from Headphonelounge.com. I have it connected to an iFi iUSB to my MacBook Pro and it works great in DAC mode. Even with the USB 2.0 from the iFi, it does not drain battery during playing and even charges if the battery is below 100% - slowly though.
I find the CDM to pair very well with the SP1000. With the stock tubes, it adds some body and a touch of warmth to the overall sound. And this is on stock tubes.