<snip> First off, for the record, I've dug into the jack/gstreamer thing, but I'm by far NOT an expert. The way I understand it, gstreamer by default looks for the jack sink by name i.e. System-> Capture1 etc. And the connects to it every time it requires to output sound, then disconnects when it's done. So, when the source is there, you can, in jack connections, re-direct it to whatever. But, when gstreamer is done playing sound it disappears, with it's connections. I may be over simplifying what may be going on in your case though... (a side note, I replaced the jack/alsa with zita/alsa connection, both work, zita is better sound quality)