diff --git a/src/gui/sysConf.cpp b/src/gui/sysConf.cpp
index 0e263a702..f7bb0bc44 100644
--- a/src/gui/sysConf.cpp
+++ b/src/gui/sysConf.cpp
@@ -1905,6 +1905,7 @@ bool FurnaceGUI::drawSysConf(int chan, int sysPos, DivSystem type, DivConfig& fl
       break;
     }
     case DIV_SYSTEM_PCM_DAC: {
+      supportsCustomRate=false;
       // default to 44100Hz 16-bit stereo
       int sampRate=flags.getInt("rate",44100);
       int bitDepth=flags.getInt("outDepth",15)+1;