Dummy loads for amplifier fault finding

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  • stj
    Great Sage 齊天大聖
    • Dec 2009
    • 31001
    • Albion

    #21
    Re: Dummy loads for amplifier fault finding

    nice

    Comment

    • redwire
      Badcaps Legend
      • Dec 2010
      • 3906
      • Canada

      #22
      Re: Dummy loads for amplifier fault finding

      It's interesting to do some math.
      With 1,000W (total) input you have around 35 minutes before the oil heats to 100°C, in a 20L barrel. So 2x500W as well. Water is much better at 105 minutes.
      Very few, if any, audio amplifiers are designed to output full power as a sine-wave for long periods of time. It simply costs too much to size heatsinks, power transformers etc for that. Many are not rated for all channels driven, just a single channel.
      My old (fanless) home-made gear can do it, but that is a DIY norm for audio power amps.
      I hate parties where the crappy cheapy A/V receiver overheats and cuts out or blows up after 1/2 hour. Buzz kill!

      Comment

      • stj
        Great Sage 齊天大聖
        • Dec 2009
        • 31001
        • Albion

        #23
        Re: Dummy loads for amplifier fault finding

        water expands and contracts - not good in a can!

        Comment

        • check12
          Senior Member
          • Nov 2012
          • 103
          • UK

          #24
          Re: Dummy loads for amplifier fault finding

          Yeah thought about distilled water when putting it together (which is pretty cheap) but got offered the oil free & it gives plenty time ... easy to build in thermometer or pressure releases too but I've never bothered ..

          Comment

          • redwire
            Badcaps Legend
            • Dec 2010
            • 3906
            • Canada

            #25
            Re: Dummy loads for amplifier fault finding

            I think the water volume goes up around 4% from 20-100°C so 20L becomes 20.8L... time for an expansion tank lol. I wonder how those oil-filled electric radiant heaters handle it.
            Otherwise it's cooling fans I guess, on larger resistors not immersion heating elements.

            Comment

            • check12
              Senior Member
              • Nov 2012
              • 103
              • UK

              #26
              Re: Dummy loads for amplifier fault finding

              5mins @ 6kW is plenty of time for a barrage of tests ...
              Attached Files

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