MXR M-103 Blue Box



  • Output
    controls the output volume
  • Blend
    controls the mix between the input signal and the octave signal



This unassuming little box shovels out enough low frequencies to scare a blue whale. It takes your guitar signal, fuzzes it up, then duplicates it two octaves down. You control the output and the mix between the dry signal and the effect. Using it 100% wet is quite an experience, but more recognizable sounds appear as you dial In more dry signal. The Blue Box is known for having a chaotic personality that can make each session a totally unique experience!

Power: Single 9 volt battery or Dunlop ECB-002 AC adapter

Controls: Footswitch toggles effect on/bypass (red LED indicates on) Output knob sets total output gain Blend knob adjusts ratio of dry (clean) with wet (effects) signal

  • 4-3/8" x 2-3/8" x 1-1/4"
  • 0.9 lbs.
  • Blue


myFXDB user reviews

1 review, average score of 7.5 / 10

2016-09-02wiendahlscript reissue7.5/10  nothing compares 2 u, blue box. your sound is fat and thick and down low and glitchy in all the right ways. fool in the rain solo best evanot enough control over the sound or the tracking. would be nice to have a switch or a level for just one octave down. must slam output...

Most recent forum threads


Link to this page

Here's some code to post a link with image on forums, eBay, websites,...
BB Code
(sites, eBay,...)

Where to find one?

your browser doesn't support AJAX?

fx pedal stompbox stomp box guitar effects pedal diy
Syndicate content

Subscribe to our newsletter

Also check out Effects Database's social media accounts: