ee593dfb   
   XPost: sci.electronics.design   
   From: burrynulnulfour@ppllaanneett.nnll   
      
   Stretto wrote:   
   > I am trying to diagnose a problem with an amplifier. I was using a   
   > freq. sweep input and noticed than when I turned the gain up the I was   
   > hearing the sound. There is no speakers hooked up and the sound seems   
   > to be an exact replica. I did not try other sounds as it seems pretty   
   > obvious that something is making reproducing this sound and it is not   
   > coincidence.   
   >   
   > I guess I could make some type of acoustical amplifier to probe around   
   > the circuit to find where it is coming from but besides that is   
   > anything I should look for? Maybe this is a natural thing? I suppose   
   > there is the possibility of a resistor or cap producing the sound due   
   > to some strange effect or it could be the sum of all the minute   
   > effects from each component but most likely it is something pretty   
   > straight forward(bad tube)?   
   >   
   > Any ideas where I should start looking?   
   Even a wire close to some steel will start singing at high currents.   
      
   --- SoupGate-Win32 v1.05   
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