AFAIK, there is no official tarball. I know the Fedora project provides one at http://pkgs.fedoraproject.org/repo/pkgs/dtc/dtc-v1.4.0.tgz/993e14242818bcfd801edd4f27ddd5a3/dtc-v1.4.0.tgz .
If it's ok, I will change to it.