diff --git a/lib/wallet/masterkey.js b/lib/wallet/masterkey.js
index 57aa2de9..b7998248 100644
--- a/lib/wallet/masterkey.js
+++ b/lib/wallet/masterkey.js
@@ -48,7 +48,7 @@ function MasterKey(options) {
   this.timer = null;
   this.until = 0;
   this._onTimeout = this.lock.bind(this);
-  this.locker = new Lock(this);
+  this.locker = new Lock();
 
   if (options)
     this.fromOptions(options);