XPost: sci.electronics.design   
   From: hill@rowland.harvard.edu   
      
   Joe Hey wrote...   
   >   
   >On 9 Jan 2016 09:05:45 -0800   
   >Winfield Hill  wrote:   
   >   
   >> Tauno Voipio wrote...   
   >>>   
   >>>On 8.1.16 20:53, DaveC wrote:   
   >>>> www.ebay.com/itm/252219274391   
   >>   
   >>  Class AA OP Preamp /Headphone Amplifier   
   >>   
   >>> I made a LTSpice model of it, but was too lazy to build   
   >>> the model for NE5532, so I used LT1358 instead.   
   >>>   
   >>> There is non-inverting amplifier with a gain of 4.3 and   
   >>> an exotic current booster at the output.   
   >>   
   >> snip clip clip ---   
   >>   
   >>  The "current booster" simply measures the current into the   
   >>  load and injects the same amount of current into the output   
   >>  op-amp's node, so that it experiences zero load current.   
   >   
   > That's probably why they call it 'AA': Two class-A amplifiers,   
   > one for the voltage, one for the current (as if that doesn't   
   > generate a voltage).   
      
    Of course, neither op-amp is running class A.   
      
      
   --   
    Thanks,   
       - Win   
      
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