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[Help] MXR M87 doesn't show any meter led while playing?

Discussion in 'Effects [BG]' started by KulNova, Dec 14, 2012.

  1. KulNova


    Oct 9, 2012
    Saigon, Vietnam
    Hi every one,

    I've just received an MXR M87 Bass Compressor, bought from MusiciansFriend. It looks great, and give some cool tone for me in the first try.

    However, I have a problem with that. When I first plug the DC in, the meter leds are all turn on for a few seconds. After that, no more meter led, no matter how I set up the knobs and how loud I play... Reading the FAQ, it's written that I should adjust the input knob to reach 3-7 green leds on... However, I can't get them on :( Tried to unplug the DC and plug again, they are all on for a few seconds again :(

    I'm not sure if I did anything wrong or is it normal or is it a mal-function from MXR :( Could you please help with your experience?

    There's no meter led while I play the bass, even though if produces different sounds to the bypass sound.
  2. scottfeldstein

    scottfeldstein Supporting Member

    Jun 20, 2011
    West Bend, Wisconsin
    Are you getting sound out the other end while you're cranking the Input knob to max? If so, then you may need to contact them.
  3. Forgive the obvious questions: Have you got the compressor engaged, by using the foot switch? (I guess you must have had it engaged, since you say the bypassed sound is different.) The blue LED in the center of the pedal should be on. The volume should change when you adjust the input and output knobs. Have you tried it with the volume on your bass turned all the way up, the compressor input turned all the way up (and the output turned down temporarily), no other pedals between your bass and the compressor, and played hard on the low strings?

    Maybe your bass has very low output. What kind of bass is it? If you want to experiment, you could try it with a different bass. Or try putting another pedal in between, one that will boost the volume.

    The meter LEDs going on then off when you turn on the power is normal.
  4. CElton

    CElton I'm a new note finder...

    Are you using the correct DC power supply? Have you tried using it with a battery?
  5. SirMjac28

    SirMjac28 Patiently Waiting For The Next British Invasion

    Aug 25, 2010
    The Great Midwest
    +1 I had that compressor it also depends on how high the threshold is? they light up when the pedal compresses the signal bring the threshold down and then see.
  6. rubber_ritchie


    Feb 2, 2008
    Thank you so much BassilPesto! You solved my problem. I turned the input on pedal up to full. The output to very low, turned by bass volume up full and the pedal lights lit up like a Xmas tree :) So happy now. Thank you!
  7. Nighttrain1127

    Nighttrain1127 Supporting Member

    Nov 27, 2004
    Near Worcester MA
    The First M87 I had did the same thing no leds to be able to set the pedal up. Sent it back to MXR and they replaced it .