dynamic compressor schematic

Passive Dynamic Audio Compressor

This dynamic compressor with passive components reduces high signal to a lower, more constant signal. If you look at this compressor schematic, you’ll notice it has no power supply, the required power is obtain thru the output signal.
If you respect the schematic values this audio compressor will output a constant 70mV when the input voltage is between 100mV and 10V!

Passive compresor circuit diagram

dynamic compressor schematic


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  • BackoHz

    Thanks for good idea. I solded it for bass guitar. Distortion, low output level. 2-3hours for experiments….and that is it.
    Sorry for my BAD english.

  • ProctorSilex

    I see a lot of differing specs on the AA119 with a forward voltage ranging from 0.25v to 2.2v. What are the specs on the diodes for this circuit so that I can find an equivalent? I asked the same question on another circuit, but it would be good to have the answer in both places.


  • milesrhart

    Hmm, never heard of an AA119, have to look that one up…
    Looks like a cool circuit,I would love to see more passive cicuits like this…

  • The Fox

    Thanks for this!

    What is the VR for?

  • Moe

    the 70mV came from the diode i thin you should just put 2x for each in for 1,4V or you can add just one shottky with 50mV.

    Google Uf Forwardvoltage

  • Immo

    How the design specs should be changed for compressor to cope well with bass guitar? A friend of mine constructed this thing from the diagram and it was deforming sound and reducing the signal way to much… But I’d like to install it in my vintage custom bass as it has much free space within the body and I’d like to have more sound-changing capabilities, while the active electronics would be blasphemous for an instrument of that kind… I’m completely ignorant in electronics and I’d have it built by my pro friend, but he needs to know the correct specs.
    Thanks alot for any future feedback.

  • Ugur Akgoz

    Thanks for the circuit.
    Very primitive but very effective and useful.

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