preamp/amp matching

Discussion in 'AV Receivers' started by Aris A, Feb 2, 2004.

  1. Aris A

    Aris A Stunt Coordinator

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    Hi..just recently purchased a used sherwood newcastle(am9080)amp at audiogon. Haven't set it up since I'm still shopping for a preamp. I read the HTF Glossary terms about impedances and damping factor but still hazy to me, sorry no electronic background to understand those much deeper. I read that this terms are important to match preamps to amps. Can you cite me a numerical example so as to have an idea what to look for my new preamp. Here's some of the specs of the amp:

    THD - 8 ohm 20hz-20khz/1 watt
    ENTER MODULATION DISTORTION - 8 smpte 1watt
    INPUT SENSITIVITY - 47 K (1000mv)
    FREQUENCY RESPONSE - 5Hz-450KHz
    DAMPING FACTOR - 125

    I have a JBL LX990 mini bookshelves speakers (90 db)
     
  2. David Judah

    David Judah Screenwriter

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    They are referring to the output impedance of the preamp and the input impedance of the amp. It happens in the same way between the two components like how speakers present a load to the amp.

    It might have been an issue in the past, especially with tube gear but it's doubtful you'll have anything to worry about with solid state equipment now. It's something to keep your eye on though. I think the general rule of thumb is a 10:1 ratio minimum between the amp and preamp.

    DJ
     

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