diff --git a/ChangeLog b/ChangeLog
index d45f228297..a95957e4ce 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2008-04-06  Tim-Philipp Müller  <tim at centricular dot net>
+
+	* ext/jack/gstjackaudiosink.c: (gst_jack_audio_sink_class_init):
+	  Work around missing bits of thread-safety on older GLibs some
+	  more to avoid assertions when starting up multiple playbin
+	  objects concurrently (see #512382).
+
 2008-04-06  Sebastian Dröge  <slomo@circular-chaos.org>
 
 	Patch by: Sjoerd Simons <sjoerd at luon dot net>
diff --git a/ext/jack/gstjackaudiosink.c b/ext/jack/gstjackaudiosink.c
index 42dda79a6f..5223e4d00a 100644
--- a/ext/jack/gstjackaudiosink.c
+++ b/ext/jack/gstjackaudiosink.c
@@ -773,6 +773,10 @@ gst_jack_audio_sink_class_init (GstJackAudioSinkClass * klass)
   gstbaseaudiosink_class->create_ringbuffer =
       GST_DEBUG_FUNCPTR (gst_jack_audio_sink_create_ringbuffer);
 
+  /* ref class from a thread-safe context to work around missing bit of
+   * thread-safety in GObject */
+  g_type_class_ref (GST_TYPE_JACK_RING_BUFFER);
+
   gst_jack_audio_client_init ();
 }