Capacitor ratings of AMPS

Discussion in 'Archived Threads 2001-2004' started by Kevin. W, Sep 19, 2001.

  1. Kevin. W

    Kevin. W Screenwriter

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    I curious to what rating the capacitors of an AMP should be. I read pamphlets, website stats and most of the upper end AMP have 10,000uf British Slit Foil Capacitors. What does this mean? What rating should an AMP have to ensure proper function during those fluctuations of movies that require extra juice.
    Kevin
     
  2. Paul_Spalvieri

    Paul_Spalvieri Auditioning

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    Being interested in that same topic when researching amps I found that most reasonably built amps use 10,000 micro farads as capacitors. What makes the difference is how many are used per channel and also how many Toroidal Transformers are used. These all provide the "juice" for what you are looking for. Happy researching and remember...no one every critises people who buy quality components. So wait alittle longer if need be and buy the right one.
     
  3. Hank Frankenberg

    Hank Frankenberg Cinematographer

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    Hi, I studied power supply design for a while and can tell you that the large capacitance caps that are mentioned in amp companies' advertising are the power supply "storage" caps. In linear power supplies, these components (usually two) follow the input transformer and bridge rectifier sections. The storage caps perform two important functions:
    they store energy every half-cycle to ensure that the dc output to the voltage step-down and regulation stages that follow is level and doesn't fluctuate. They also, by the nature of the circuit design, filter out a lot of the 60 Hz "hum" that might make its way to the amps' output. That's the simple explanation. That said, those electrolytic storage caps are one of the more expensive components in a linear power supply, and as with many items, the larger, quality storage caps will be in the more expensive equipment. A robust power supply with plenty of reserve and large storage caps is important in delivering clean, undistorted or clipped sound during high SPL passages in music and movies. As a rule, low-end gear, both amps and the amp section of receivers, have power supplies designed for minimal cost (including small storage caps), and will exhibit "strained", distorted sound during high SPL transients, and may even clip, which is BAD for speakers. BTW, did you know that the weakest circuitry in most TV's is the power supply? It's responsible for a number of circuit/picture performance and stability parameters, and TV power supplies are definitely designed for minimal cost.
    Probably more babbling than you wanted to read, but hey, it's early and I feel eloquent [​IMG]
    ------------------
    "Do you expect me to talk?"
    "No Mr. Bond, I expect you to die!"
    [Edited last by Hank Frankenberg on September 20, 2001 at 07:04 AM]
     
  4. ling_w

    ling_w Second Unit

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    Manufacturers use various type of capacitors of various size on their power supply for different reasons.
    A bank of large soda can size electrolytic capacitors in order to get the most storage reserve out of their power supply. But there are disadvantages to them.
    They are made for large power reserves, but are not optimal for quick release of its energy. This causes it to not be able to keep up with the energy delivery requierment of amplifying high freq signal. To overcome that, manufactures frequently use poly/teflon bypass capacitors so that instant energy requirement is satisfied. Other manufactures might use banks of smaller capacitors so that the caps responds faster to massive energy requirements. Then there are guys who put reserve caps right in front of each transistor.
    Then there are variations, like using slit foil capacitors or even using large amount of film caps. So a large 2ch amp might have over 30 of these smaller 10,000 uF electrolytic caps.
     

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