Just some questions

Discussion in 'Archived Threads 2001-2004' started by Will Pomeroy, Feb 10, 2002.

  1. Will Pomeroy

    Will Pomeroy Stunt Coordinator

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    I just have a few questions that I’d like to ask:

    1) What would happen if I were to put an already high power signal (from a receiver into another amp? would it just destroy everything?

    2) What’s the difference between a passive x-over and an active one?

    3) What’s does discrete mean, when used in the context of "Discrete signals" or "Discrete amp"

    Thanks very much, any answer would be greatly appreciated
     
  2. Jim Mc

    Jim Mc Agent

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    Do not feed the output of one amp into the input of another.

    Discrete means "seperate or individual".
     
  3. Bill Catherall

    Bill Catherall Screenwriter

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    I'll answer #1. I don't know #2. Jim got #3 correct.

     
  4. Bill Catherall

    Bill Catherall Screenwriter

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    Ok...I found the answer to #2
    • Active crossovers:
    • Active crossovers are placed before the power amplifier in any system (including stereos.)
    • Active crossovers have an active element in them (usually an op-amp.) This is to provide buffering. In effect buffering keeps one stage of a system from interacting with the one before it. Imagine if changing speakers made your CD player perform differently. That would be a nightmare. Buffering eliminates this. Active crossovers are buffered.
    • Active crossovers need a power supply for the op-amps (or their replacement.)
    • Active crossovers deal with much lower power circuits than passive ones. This is because the signal has not been amplified to the speakers level yet.
    • This is a biggie. Active crossovers need a separate power amp for every output from the crossover. If you have a two way crossover, you need two amplifier channels per speaker.
    • Active crossovers are more efficient with amplifier power than passive because they can not dissipate amplifier power.
    • Active crossovers can use many amplifiers of lower power to form the equivalent of a single, more powerful amplifier.
      Passive crossovers:
    • A passive crossover is placed between the power amplifier and the speaker.
    • The passive crossover interacts with the impedance of the speaker.
    • A typical passive crossover will have less parts because it has no power supplies or buffer stages.
    • Passive crossovers deal with much higher voltage and current signals than active crossovers.
    • Parts cost more for passive crossovers because they must deal with more power (but there are less parts.)
    • Passive crossovers conveniently can be hidden inside speaker boxes because they come after the amplifier stages.
    • Passive crossovers usually contain at least one resistor, which consumes power that will not find its way to the speaker, making the speaker / crossover less efficient.
    • The whole speaker can run off of one amplifier channel, no matter how many ways the crossover splits up. This may result in a very significant cost savings.
     

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