ee593dfb   
   XPost: sci.electronics.design   
   From: Pimpom@invalid.net   
      
   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?   
      
   I've been using cheap medical stethoscopes for a few decades to   
   locate the source of a sound, in electronics and while tinkering   
   with my car. I remove the diaphragm-bell assembly and point the   
   open end of the pipe at various parts until I locate the culprit.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)