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good books on amplifier construction

Discussion in 'General Electronics' started by pil, Apr 10, 2004.

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  1. Fred Stevens

    Fred Stevens Guest

    Have a look at the book on Audio Ampifier design by Douglas Self. He
    also has a website which you could find using Google.

  2. Ban

    Ban Guest

    It's still an art to develop a digital amp. There is a company Tripath which has specialized in high quality digital amps.
    They use a delta sigma approach with feedback directly from the output of
    the switching stage. The results are really good sounding amps, satisfying
    even high-end requirements.

    Pulse width modulation is digital. It fulfills the basic requirements of
    digital, which means quantized and time discreet. The output stage has only
    2 states and the repetition of that switching follows a fixed time pattern.
    If the width is continously variable or in steps doesn't make it analog. The
    advantage of a digital output stage is the high efficiency and subsequently
    much higher power you can achieve with the output devices. So the main
    fields of application are in very high power amps or very small lowish
    (0.5-2W) output stages for cellphones and PDAs. But I'm sure in future most
    if not all amps will be working like this.
    The delays ocurr only with long digital FIR filters, not necessarily. The
    output needs to be filtered as well, usually a L/C passive filter, which
    adds a delay according to its minimum phase characteristic. With a second
    order filter this delay is usually only a few(2-5) microseconds.

    That was maybe 20yrs ago. It is still cutting edge technology, but since
    Sony has introduced SACD with a fixed 2.8224MHz modulation, this argument is
    totally bogus. It outperforms by far any CD quality. Sony offers all-digital
    amps as well, which are optically coupled to the SACD-player, no analog in.
    Sure there must be an analog output voltage because our ears work analog,
    but this is done with that passive L/C lowpass mentioned before.

    I'm currently designing a digital amp. It has analog inputs, and an analog
    delta-sigma modulator, but then the signal is digitized and processed
    digitally. Since this is not a commercial product, but for my own delight,
    I'm willing to share my approach with anybody interested and can post the
    schematics on ABSE when done. You can also drop me a mail to have a look at
    the current state.
  3. Karl Uppiano

    Karl Uppiano Guest

    There are many who would disagree that SACD is in any way superior to CD
    audio. Several respected pioneers in digital audio believe that SACD is
    fundamentally flawed; that it ignores some very fundamental principles
    necessary for a high quality sampled data system. As far as my argument
    being totally bogus, you'll have to explain that. Distortion figures for the
    best class "D" amplifiers I've seen so far exceed the best linear amplifiers
    by a factor of at least ten.
  4. Neil Preston

    Neil Preston Guest

    Pro audio is wholeheartedly embracing the fully digital amplifier. Crown
    Audio makes the CE4000 and other models that are fully digital, and Peavey
    has been making digital amps since the '80s. I'm sure there are others.....

    Neil Preston, CET
    Preston Electronics, LLC
  5. Ian Bell

    Ian Bell Guest

    Please define 'fully digital'

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