I've tried a couple different plugs, and they've all worked - so not surprised to hear others have plugs that work well for them. But using a known properly spec'd connector would give me peace of mind.
The spring-loaded portion of the DC power connection resides inside the female connector, in the unit. You can see a small nub inside the outer ring of the female receptor that provides a little pressure against the male plug when inserted. In other words, the spring-loading component of the mechanism has nothing to do with the male connector plug, which is why I'm frustrated by Tascam's unwillingness to share the spec for the male plug. I'm not asking them to source one for me, tell me where to find one (since they claim it's only available through them), I simply want to know the specs so I may determine myself if the male plug's available elsewhere.