diff --git a/src/sink.cpp b/src/sink.cpp
--- a/src/sink.cpp
+++ b/src/sink.cpp
@@ -69,7 +69,7 @@
 
 void Sink::setDefault(bool enable)
 {
-    if (enable) {
+    if (!isDefault() && enable) {
         context()->server()->setDefaultSink(this);
     }
 }
diff --git a/src/source.cpp b/src/source.cpp
--- a/src/source.cpp
+++ b/src/source.cpp
@@ -69,7 +69,7 @@
 
 void Source::setDefault(bool enable)
 {
-    if (enable) {
+    if (!isDefault() && enable) {
         context()->server()->setDefaultSource(this);
     }
 }