Amplify sound card output

Discussion in 'The Projects Forum' started by nenadilic84, Aug 17, 2009.

  1. nenadilic84

    Thread Starter Active Member

    Aug 7, 2009
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    I have a similar problem, so I didn't want to start the new thread.
    I want to amplify a signal from my laptop computer sound card to drive an inductive load. The signal have to be amplified to 65V p-p. I have made 100 Wat power supply that has something about 68.5 Volts DC.Where to start??? Can anyone help???

    Thx,
    Nenad
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. nenadilic84

    Thread Starter Active Member

    Aug 7, 2009
    62
    0
    Thanks I saw that, but I thought that there was something simple I can do...
    What do you suggest for amplifying a signal to 65Vp-p but instead of inductive load that I mentioned earlier I have a resistor that is something like 250KOhm to 400KOhm

    I had found some thing like this.... How can I use it, modify it...

    I run it throw a simulation but I think it has some errors.

    Also I dont need I voltage doubler because I have 70V DC power supply


    [​IMG]
     
  4. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    We really prefer that you not hijack a thread, so now you have your own.

    This is the original - http://forum.allaboutcircuits.com/showthread.php?t=26737

    Can you say more about the application? There is simply an enormous difference between a high value resistor and an inductive load.
     
  5. nenadilic84

    Thread Starter Active Member

    Aug 7, 2009
    62
    0
    Sorry for that...

    I was thinking of using this circuit for testing purpose, and after testing if every thing is ok use it as a pre-amplifier...

    So let's asumet that I need to drive a 200KOhm resistor....

    Thx,
    Nenad
     
  6. nenadilic84

    Thread Starter Active Member

    Aug 7, 2009
    62
    0
    Hi I made a simulation but the circuit is inefficient.. Any suggestions on how to increase efficiency??
    Also, I assumed that the output of my sound card is 2V AC... Is that correct???

    [​IMG]
     
  7. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    Your sound card output is on the order of 1.2 VAC out. It may even be a bit lower, as I need a higher volume setting running my amp off my card.

    Can't comment on you simulation, as it is not posted.

    You will need the equivalent of an audio amplifier. For better efficiency, try a class AB design.
     
  8. nenadilic84

    Thread Starter Active Member

    Aug 7, 2009
    62
    0
    HI I made a circuit I showed in my previous thread, but I'm not sure how to connect output of my sound card to the amplifier. I'm afraid not to burn my card because I'm getting 2.8Volts from the feedback... Any suggestions?

    Thx,
    Nenad
     
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