AudioAppComponent silent in VS2013 release

Hi Guys,  I have a VS2013 project that works brilliantly in debug.  I just built it in release for a tester, and there is no sound.  It has to be something simple - numbers are going into the buffers in getNextAudioBlock just as in debug, but no sound is coming out. Any suggestions as to a cause would be appreciated.

Maybe you've got some important code inside a jassert() statement, so that it won't be run in release mode?