2 Replies Latest reply on Nov 23, 2014 6:54 PM by nick123

    Pre-Amp

      What is a pre-amp?

        • Re: Pre-Amp
          D_Hersey

          In the stereo world it was an amp between the transducers and the PA.  It was responsible for things like tone control so that signal processing wouldn't have to be done in the PA (power-amp) where it would require more power.

           

          Often superhets have the antenna, mixer and LO before the first gain-stage, an IF amp.  If an RF amp was inserted to the left of the mixer, it was called a pre-amp.  Unless these pre-amps were really quiet, they weren't of much value.  They use stuff like GaAs HEMT in this application, earlier they used specially-configured pentodes.  During the war the Germans didn't know about pentodes.  They used tetrodes with active loads, which performed nearly as well.