diff --git a/board-package-source/libraries/ATMlib/src/ATMlib.cpp b/board-package-source/libraries/ATMlib/src/ATMlib.cpp
index 8b83c11..9c744af 100644
--- a/board-package-source/libraries/ATMlib/src/ATMlib.cpp
+++ b/board-package-source/libraries/ATMlib/src/ATMlib.cpp
@@ -109,6 +109,7 @@ static inline const byte *getTrackPointer(byte track) {
 
 
 void ATMsynth::play(const byte *song) {
+  TIMSK4 = 0b00000000;// ensure interrupt is disabled
   cia_count = 1;
   // cleanUp stuff first
   memset(channel, 0, sizeof(channel));