XPost: sci.electronics.design   
   From: rwinner@remove_this.hmamail.com   
      
   * It may have been the liquor talking, but   
   Lord Valve  wrote:   
      
   > 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?   
   >   
   > 1) Don't run your amp without a load on it.   
   >   
   > 2) Google "magnetostriction."  That's what's   
   >     happening in your output transformer.   
   >   
   > LV   
      
   Yes, I've heard that is bad news, also. Never run it out to an open circuit.   
      
   *R* *H*   
   --   
             Powered by Linux	        |/     2.6.32.26-175 Fedora 12   
    "No spyware. No viruses. No nags."     |/   2.6.31.12-0.2 OpenSUSE 11.2   
          http://www.jamendo.com           |/   
       "Preach the gospel always; when necessary use words."  St. Francis   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)