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Soundcard Input Impedance and a PreAmp Q

Discussion in 'Preamps & Processing' started by Kemble, Nov 28, 2004.

  1. Kemble

    Kemble Guest

    I haven't been here in about a year and it is great to see many familiar names and lots of new ones too.

    I have been looking into my signal path as it will be (hopefully) after Christmas time. Which led to looking at impedance matching and proper paths. (something I needed to better understand).

    The outputs of my preamp or compressors is LoZ (51 ohm for the PreAmp- Presonus Tube Pre- and a few hundred for the compressor).
    I have been and will continue to use a MAudio Delta44. Which has a high impedance input as best as I can tell/know. Yeah, I'm sure its HiZ.
    The manual says that the Input Impedance is NOT LESS THAN 10K ohm MINIMUM.

    LoZ should not feed HiZ, but a guitar effects pedal has a LoZ output (right?) and it feeds HiZ input on an amp. But it is a powered LoZ signal, so I'm guessing that makes a differnce.

    So HERE IS THE QUESTION- If the soundcard says 10Kohm MINIMUM and I'm feeding it directly from my preamp or compressor or whatever (which is the correct way to do it) am I loosing some of the signal or doing it wrong?
    What is the deal here? :? Why would the card say that when its not the way the signal path would arrive at it?

    Sorry for rambling.

  2. Sebatron

    Sebatron Well-Known Member

    Dec 22, 2002
    No that's wrong.It should be the other way around.
    LoZ output has more current so it can feed HiZ input.
    HiZ output has less current and is easily loaded ( sunk ) by a LoZ input....

    Z can be viewed as 'sensitivity'.... in regard to inputs ....
    HiZ=> more sensitivity .... and easily tripped
    LoZ=>less sensitivity ..... requires more current

  3. Kemble

    Kemble Guest

    Got it.
    a LoZ mic won't properly feed a HiZ input successfully. Is this just because there is no power behind the mic signal? TONS of signal, but no power?

    I was just put off by the manual saying that the input impedace was 'minimum 10K ohm' and I thought I was feeding it a mismatched signal.

  4. David French

    David French Distinguished Member

    Jun 19, 2002
    Hi Jeff, I remember you! Can you believe they made me a moderator?!? :shock: Welcome back! :D
  5. Kemble

    Kemble Guest

    Hey, David, nice promotion!
    I had to drop the ball on music production for a long while due to its high-time-consumption/low-income-creating/money-consuming ratios.
    Hows that for a long way to say I stopped recording and building acoustic treatments for a while??

    I've been recovering from a hip surgery so I've had lots of time to read and get reaquiainted with my music. Its such a blessing to have a gift of music to fall back to when I need to express myself or just beat the bordom! Gee, imagine how bored Brittany Spears would be! :lol:

    This is unrelated, but funny: The docs and I had come to the concensus that the hip injury I had was from my career in footbal which extended into college. It was the only thing that made sense. However.... I was in HomeDepot getting items to build a bass trap when I remembered climbing onto a stack of plywood 2 years ago and falling off and jamming my hip in a terrible way. After which I couldn't walk due to hip pain.

    So much for having some heroic story............

    Its great to be back here and I look forward to learning; and maybe even chiming in once in a while with my limited knowlege.

  6. David French

    David French Distinguished Member

    Jun 19, 2002
    Good to have you back! :)

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