Connect the channel one output of the mic pre-amp to channel one of the oscilloscope with a BNC to BNC cable. Clean the top of the longest tube and hold it near (but not directly in front of) the micr...Connect the channel one output of the mic pre-amp to channel one of the oscilloscope with a BNC to BNC cable. Clean the top of the longest tube and hold it near (but not directly in front of) the microphone. Once you are able to achieve a clear, solid tone, check the oscilloscope display to make sure that it is showing one to two cycles of the wave and that the amplitude fills the vertical portion of the display without going beyond it.
