diff --git a/libs/ardour/delivery.cc b/libs/ardour/delivery.cc
index 8dcedc4e1f..fa57e7294e 100644
--- a/libs/ardour/delivery.cc
+++ b/libs/ardour/delivery.cc
@@ -198,6 +198,7 @@ Delivery::set_gain_control (std::shared_ptr<GainControl> gc)
 		_gain_control = gc;
 		_amp.reset (new Amp (_session, _("Fader"), _gain_control, true));
 		_amp->configure_io (_configured_output, _configured_output);
+		_amp->activate ();
 	} else {
 		_amp.reset ();
 		_gain_control = gc;