Thanks for your help!
In case of need, i did it this way:
![image](https://community-assets.home-assistant.io/original/3X/6/6/668a9011690b54dfda928aeb5175e60ae3ffc453.png)
A trigger state filters only the changes of the amp, and then the switch check for the new_state value then output depending on wanted values.
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Here is the code to import both blocks in node red to easilly reproduce ![:slight_smile: :slight_smile:](https://community.home-assistant.io/images/emoji/twitter/slight_smile.png?v=9)
[{"id":"dacff821.ec7bd8","type":"trigger-state","z":"332a7a59.32aba6","name":"amp","server":"1a8176b8.732339","exposeToHomeAssistant":false,"haConfig":[{"property":"name","value":""},{"property":"icon","value":""}],"entityid":"media_player.amp_salon","entityidfiltertype":"exact","debugenabled":true,"constraints":[],"constraintsmustmatch":"all","outputs":2,"customoutputs":[],"outputinitially":false,"state_type":"str","x":90,"y":580,"wires":[["371ff164.badaa6","40018cc1.8c9eec"],[]]},{"id":"371ff164.badaa6","type":"switch","z":"332a7a59.32aba6","name":"amp_source","property":"data.event.new_state.attributes.source","propertyType":"msg","rules":[{"t":"eq","v":"Moode-Audio","vt":"str"},{"t":"eq","v":"PC","vt":"str"},{"t":"eq","v":"Switch","vt":"str"},{"t":"eq","v":"tv","vt":"str"}],"checkall":"true","repair":false,"outputs":4,"x":250,"y":640,"wires":[["b4b2e337.6a1aa"],["54c33909.592638"],["54c33909.592638"],["54c33909.592638"]]},{"id":"1a8176b8.732339","type":"server","z":"","name":"Home Assistant","addon":true}]
Hope it helps!