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Isolation b/w DAC & Power amplifier

Discussion in 'General Electronics Discussion' started by masudasim, Aug 25, 2012.

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  1. masudasim

    masudasim

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    Aug 25, 2012
    Hello

    i am using NI DAC (6723) to drive QSC RMX 4050HD Power amplifier (PA) having input impedance of 10 kohm. I am generating 1-5KHz sinusoidal signals from my DAC.

    1- I need some isolation & signal smoothing b/w DAC & 2kWatt PA.

    2- Secondly, NI DAC has current limitation of 5mA/channel. I also desire to boost this capacity to say (10mA/channel) with some IC b/w DAC output & PA input.


    Can any one kindly suggest some type of analog isolation IC/transformer which can do this job?


    Thanks

    Best Regards
    asim
     
  2. Harald Kapp

    Harald Kapp Moderator Moderator

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    Nov 17, 2011
  3. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    652
    May 8, 2012
    I just gotta know! What will you be doing with a 2KW sinewave?
     
  4. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    652
    May 8, 2012
    I don't get any of this. If the input Z of your amp is 10KΩ it would require an input voltage of 100V to draw 10mA! :eek:
     
  5. masudasim

    masudasim

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    Aug 25, 2012
    I need to drive a acoustic transducer with this voltage
     
  6. BobK

    BobK

    7,682
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    Jan 5, 2010
    I just gotta ask: what does a smoothed sine wave look like?

    edited: never mind, I see that it is a DAC output, so smoothing (usually know as filtering) does make sense.

    Bob
     
  7. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    652
    May 8, 2012
    According to this the PA is driving the acoustic transducer. Your DAC needs to drive the 10KΩ input to the PA. You need a HiZ (>=1MΩ) input to an OpAmp to properly interface a DAC output.

    Chris
     
    Last edited: Sep 1, 2012
  8. Merlin3189

    Merlin3189

    250
    69
    Aug 4, 2011
    Not a comment - I just wonder what " b/w " means in this context.

    I can't see how "bandwidth" or "black and white" would fit, so I wonder if there's another meaning I should know?
     
  9. Geonovast

    Geonovast

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    2
    Aug 26, 2012
    b/w = between.
     
  10. masudasim

    masudasim

    6
    0
    Aug 25, 2012
    Dear
    Thanks for reply

    "According to this the PA is driving the acoustic transducer. Your DAC needs to drive the 10KΩ input to the PA. You need a HiZ (>=1MΩ) input to an OpAmp to properly interface a DAC output"

    Yes, Opamp with input impedance >1Mohm are easily available but problem is that i will not get isolation by using it b/w DAC and PA input
     
  11. Harald Kapp

    Harald Kapp Moderator Moderator

    11,702
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    Nov 17, 2011
    An audio transformer helps, see my first answer.
     
  12. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

    4,960
    652
    May 8, 2012
    As Harold said, you can use a small audio transformer. You'd connect it between the OpAmp output and the PA input.

    Curious though.. Why do you need isolation?

    Chris
     
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