diff --git a/lib/Onkyo.js b/lib/Onkyo.js
index 2dfa157..9f83483 100644
--- a/lib/Onkyo.js
+++ b/lib/Onkyo.js
@@ -734,7 +734,7 @@ class Onkyo extends EventEmitter {
   setVolume(volume, zone) {
     invariant(_.isInteger(volume), 'volume should be an integer');
     invariant(volume >= 0, 'volume should be 0 or above');
-    const volumeHex = volume.toString(16).toUpperCase();
+    const volumeHex = volume.toString(16).toUpperCase().padStart(2, '0');
     const rawCommand = OnkyoCmds.getZoneCommand('MVL', zone) + volumeHex;
     return this.pwrOn(zone)
       .then(() => this.sendRawCommand(rawCommand)