diff --git a/mopidy/backends/spotify/session_manager.py b/mopidy/backends/spotify/session_manager.py
index d08a7c97..b79fc48f 100644
--- a/mopidy/backends/spotify/session_manager.py
+++ b/mopidy/backends/spotify/session_manager.py
@@ -5,11 +5,11 @@ import threading
 from spotify.manager import SpotifySessionManager as PyspotifySessionManager
 
 from pykka.registry import ActorRegistry
-from pykka.proxy import ActorProxy
 
 from mopidy import get_version, settings
 from mopidy.backends.spotify.translator import SpotifyTranslator
 from mopidy.models import Playlist
+from mopidy.outputs.base import BaseOutput
 from mopidy.utils.process import BaseThread
 
 logger = logging.getLogger('mopidy.backends.spotify.session_manager')
@@ -28,9 +28,9 @@ class SpotifySessionManager(BaseThread, PyspotifySessionManager):
         BaseThread.__init__(self)
         self.name = 'SpotifySMThread'
 
-        # TODO-PYKKA Get reference to output without hardcoding GStreamerOutput
-        output_refs = ActorRegistry.get_by_class_name('GStreamerOutput')
-        self.output = ActorProxy(output_refs[0])
+        output_refs = ActorRegistry.get_by_class(BaseOutput)
+        assert len(output_refs) == 1, 'Expected exactly one running output.'
+        self.output = output_refs[0].proxy()
 
         self.connected = threading.Event()
         self.session = None
diff --git a/mopidy/frontends/mpd/dispatcher.py b/mopidy/frontends/mpd/dispatcher.py
index 932eb3e3..b934070e 100644
--- a/mopidy/frontends/mpd/dispatcher.py
+++ b/mopidy/frontends/mpd/dispatcher.py
@@ -1,8 +1,8 @@
 import re
 
-from pykka.proxy import ActorProxy
 from pykka.registry import ActorRegistry
 
+from mopidy.backends.base import Backend
 from mopidy.frontends.mpd.exceptions import (MpdAckError, MpdArgError,
     MpdUnknownCommand)
 from mopidy.frontends.mpd.protocol import mpd_commands, request_handlers
@@ -27,9 +27,9 @@ class MpdDispatcher(object):
     def __init__(self, session):
         self.session = session
 
-        # TODO-PYKKA: Get reference to backend in a more generic way
-        backend_refs = ActorRegistry.get_by_class_name('SpotifyBackend')
-        self.backend = ActorProxy(backend_refs[0])
+        backend_refs = ActorRegistry.get_by_class(Backend)
+        assert len(backend_refs) == 1, 'Expected exactly one running backend.'
+        self.backend = backend_refs[0].proxy()
 
         self.command_list = False
         self.command_list_ok = False
diff --git a/mopidy/mixers/gstreamer_software.py b/mopidy/mixers/gstreamer_software.py
index f9d171ca..2125aab3 100644
--- a/mopidy/mixers/gstreamer_software.py
+++ b/mopidy/mixers/gstreamer_software.py
@@ -1,16 +1,19 @@
 from pykka.actor import ThreadingActor
-from pykka.proxy import ActorProxy
 from pykka.registry import ActorRegistry
 
 from mopidy.mixers.base import BaseMixer
+from mopidy.outputs.base import BaseOutput
 
 class GStreamerSoftwareMixer(ThreadingActor, BaseMixer):
     """Mixer which uses GStreamer to control volume in software."""
 
     def __init__(self):
-        # TODO-PYKKA Get reference to output without hardcoding GStreamerOutput
-        output_refs = ActorRegistry.get_by_class_name('GStreamerOutput')
-        self.output = ActorProxy(output_refs[0])
+        self.output = None
+
+    def post_start(self):
+        output_refs = ActorRegistry.get_by_class(BaseOutput)
+        assert len(output_refs) == 1, 'Expected exactly one running output.'
+        self.output = output_refs[0].proxy()
 
     def _get_volume(self):
         return self.output.get_volume().get()