1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  
    TalkBass.com has been uniting the low end since 1998.  Join us! :)

MXR M87 Bass Compressor

Discussion in 'Effects [BG]' started by fat_boy, Aug 11, 2012.

  1. fat_boy


    Sep 1, 2009
    Hanoi, Vietnam
    Hi all TB-ers,

    I just received a MXR M87 this afternoon after about 2weeks waiting.

    The first thing I would do with all my just-received pedals is to open them up, this MXR is not an exception. And I found a little switch inside of the pedal, I also tried 2 positions of it and this is the result:
    - The upper position - the default position of the switch, sounds more normal and the gain reduction lights work as usual.
    - The sound of lower position of the little switch seems to be louder but there is no gain reduction lights.

    So this is my question: can anyone tell me exactly what the function of the little switch is? As I said, i found some difference in tones of those, but can find the way to describe. And it's not mentioned in the manual user.
    Right now, I'm setting it in the default position.

    Thanks for the answers, Bros. Have a nice day!
  2. Contact mxr technical support department, they are located on Benicia California. You should have the number in the little booklets that came with your pedal

    Awesome people and very knowledgeable
  3. bongomania

    bongomania Gold Supporting Member Commercial User

    Oct 17, 2005
    PDX, OR
    owner, OVNIFX and OVNILabs
  4. fat_boy


    Sep 1, 2009
    Hanoi, Vietnam
    oh, thank you so much Bongomania!
  5. The link is dead. I just purchased a M87, and also curious about that little switch... Does anybody know what it does?
  6. scubaduba

    scubaduba Moderator Staff Member Supporting Member

    Dec 23, 2003
    From MXR:
    The internal on/off switch on the M87 Bass Compressor is for factory calibration and testing only. Not for end users.
  7. MattLou


    Dec 23, 2016
    Hi all.
    The answer from the customer service is totally wrong. Why should they put a jumper in it just for testing purposes? There are many other and cheaper ways to test it one time.

    The correct answer is in between the lines in manual. 'Current Draw LEDs off 14 mA LEDs on 19 mA'
    If you are sure with your settings you can put the led lights off and you'll save 5mA power. It means less load in power section and less noise.

    It is a shame of MXR support. Such an answer?:)))

    If you don't want to see the green leds, open it and turn them off. I like them flashing by the way.

Share This Page