Setting PulseAudio playback device before playback

I run Debian 9 with PulseAudio on a computer with two sound cards. The screenshot below shows the Volume Control application when no audio is played back. When audio is played back, a drop down is displayed where I can select the output device. Is there a way to select the output device *before* the audio stream is started? To me this seems more natural. Edit: Here is my typical use case. I want to play a song from my computer on the living room stereo (sound card B) instead of through the desktop speakers (sound card A). Since I cannot select the output in advance I have to start the song and have it played back on the desktop speakers, then select the living room speakers once the option shows up in the playback tab in the Volume Control window. Then I need to play the song from the beginning now that I have selected the desired output. This is bad UX.