Have been looking for this since I heard Soundrop was shutting down:
On November 13th 2014, popular music sharing service Soundrop announced it would be closing its doors. With no suitable alternative available, I set out to build an open-source replacement. I wanted to harness Spotify’s excellent audio quality and music library, but since they are shutting down all Spotify Apps, the only viable option was to build a stand-alone player. A month of late nights later, and the first version of Soundbounce is now ready to download.
Linux support is growing, the app runs but there are issues with audio playing and installation.
If you are interested find the details here: https://github.com/pdaddyo/soundbounce/issues/114
edit: I’ve just put a $50 bounty on someone making an Ubuntu compatible .deb for me :D