help with modification

Discussion in 'The Projects Forum' started by markosillypig, Oct 18, 2010.

  1. markosillypig

    Thread Starter Active Member

    Jul 21, 2008
    184
    0
    hi all again
    i'm making this circuit but i want to modify it to work with out the mic direct from my ipod could any one help with some scamats or help ?
    thanks
    marko
     
  2. Audioguru

    New Member

    Dec 20, 2007
    9,411
    896
    Instructables are full of mistakes because they are designed by people who know nothing about electronics.

    The LM3916 is not made anymore. An LM3915 is similar and is available.
    The LM391x and the LM386 power amplifier both need a supply bypass capacitor. Use 10uF to 47uF.

    For an ipod as the music source, remove the LM386 circuit and replace it with a volume control. The input should be a 0.33uF film capacitor (not the 10uf polarized electrolytic capacitor shown) feeding a 100k volume control. R5 is shown wrong as a volume control and should not be used. R3 should be the 100k volume control with the slider connecting to pin 5 of the LM391x.
    Pin 7 and pin 8 are shown completely wrong. See my clipping from the datasheet. Use 560 ohms for the resistor on my clipping for a current of 20mA in each LED.
     
  3. iONic

    AAC Fanatic!

    Nov 16, 2007
    1,420
    68
    I'll back Audioguru's advice and alterations.

    iONic
     
  4. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    Rumors of the LM3916's demise are greatly exaggerated:
    http://www.national.com/mpf/LM/LM3916.html#Order

    The LM3916N was phased out in 1999. The LM3916N-1 and LM3916N-1/NOPB are functionally identical, and available at authorized distributors shown on the link above.
     
  5. blueroomelectronics

    AAC Fanatic!

    Jul 22, 2007
    1,758
    98
    Now if only the LM3909 wasn't dead.
     
  6. retched

    AAC Fanatic!

    Dec 5, 2009
    5,201
    312
    Futurelec has the LM3909. ;)

    Good luck getting it though.
     
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