diff --git a/src/rtlsource.cc b/src/rtlsource.cc
index 75e53bd..c5dea4b 100644
--- a/src/rtlsource.cc
+++ b/src/rtlsource.cc
@@ -81,10 +81,8 @@ RTLSource::setSampleRate(double sample_rate) {
 void
 RTLSource::enableAGC(bool enable) {
   _agc_enabled = enable;
-  if (_agc_enabled) {
-    rtlsdr_set_tuner_gain_mode(_device, !_agc_enabled);
-    rtlsdr_set_agc_mode(_device, _agc_enabled);
-  }
+  rtlsdr_set_tuner_gain_mode(_device, !_agc_enabled);
+  rtlsdr_set_agc_mode(_device, _agc_enabled);
 }
 
 void
diff --git a/src/rtlsource.hh b/src/rtlsource.hh
index 92e270a..0335ff9 100644
--- a/src/rtlsource.hh
+++ b/src/rtlsource.hh
@@ -18,7 +18,8 @@ public:
    * @c enableAGC and @c setGain methods.
    *
    * @param frequency Specifies the tuner frequency.
-   * @param sample_rate Specifies the sample rate.  */
+   * @param sample_rate Specifies the sample rate.
+   * @param device_idx Specifies the device to be used. */
   RTLSource(double frequency, double sample_rate=1e6, size_t device_idx=0);
 
   /** Destructor. */