Simulation results

Discussion in 'The Projects Forum' started by williamthomas, Aug 26, 2013.

  1. williamthomas

    Thread Starter New Member

    Jul 26, 2013
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    Can anybody help me with my audio amplifier 20 kHz transient analysis? I am having trouble with distortion with 20 kHz and 1 v as input signal.
    If the input signal is less, then no distortion.
    the circuit is attached and the simulation program is LT Spice.

    the result is also attached. I measured the complementry output transistors collector to see the signal.
     
    Last edited: Aug 26, 2013
  2. WBahn

    Moderator

    Mar 31, 2012
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    4,796
    Uhm... Are you aware that there are numerous different schematic capture and simulation tools? That we might not have any clue as to whether we can even read your attached file unless we know which tool you are using?

    In general, it is better to post schematics (as in figures, even just screenshots) so that anyone can see what you are doing. Also, post an image of your simulation results that show the problem you are seeing.
     
  3. williamthomas

    Thread Starter New Member

    Jul 26, 2013
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    thanks. better now?
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,014
    3,234
    I can't simulate you circuit since I don't have the cordell model files, but it would appear that the output may be clipping with 1V input. The gain of the amp is about 21.6 and that would give a peak output voltage of 30V for a 1Vrms input. That voltage is greater than your supply voltage of 24V so it clips the output.

    Even if the input voltage is 1V peak, the output would be 21.6V which is close enough to the 24V supply that the output will likely be starting to clip.
     
  5. williamthomas

    Thread Starter New Member

    Jul 26, 2013
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    i tried to less the gain to 18 but it still clips with 1v input
     
  6. WBahn

    Moderator

    Mar 31, 2012
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    Can you show a graph of your input voltage and output voltage?
     
  7. JoeJester

    AAC Fanatic!

    Apr 26, 2005
    3,373
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    Can be found www.cordellaudio.com

    The txt file of the models is 0.1 kB larger than the allowed limits here. :D

    It would be nice if the OP posted a schematic picture though.
     
    Last edited: Aug 26, 2013
  8. tubeguy

    Well-Known Member

    Nov 3, 2012
    1,157
    197
    Try a gain of around 14 or 15.

    Is the clipping symmetrical?
     
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