Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Can you spot the loudness circuit on this car radio?

  1. Oct 14, 2014 #1

    Heat up and remove capacitors (see blue) C307, C301, C201, and C207. Simply land your RCA wires to the pins highlighted in red. Purple pin is GND. This should give you a solid 2V line level out. Enjoy your un-eq'd radio:)

    The above is a tutorial on how to bypass the built-in loudness circuit and get a clean line level out on a 2006 Subaru Legacy P-204UH radio. Unfortunately, I have the P-201UH model. The member who wrote this hack is long gone, so I came here. I popped open my radio only to find that the layout is different. The capacitor values he listed are not on my board. Well, maybe they are, but the labeling numbers are different. Subaru didn't change much until 09' with the 5th generation. I'm hoping this is just another matter of finding a few capacitors and removing them.

    Background: Regardless of how much time/money you have stuck into new speakers, external amplifiers, processors, etc... your stereo will only sound as good as the input signal. The loudness circuit needs to go! I want to send a clean line level to my amplifiers.

    EDIT: I can't open the PDF for some reason. Link to schematic:

    Will update when I get at the PDF
  2. jcsd
  3. Oct 14, 2014 #2


    User Avatar
    Science Advisor

    Have you compared both schematics and found the corresponding tap point on your stereo?
    Or you could make an audio probe for a few dollars and spend a few minutes to find the point that way.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook