Welcome to the Revolution

Hi there, welcome to my blog - La Revolution Deux. It's an odd name - but I like it! Here you will find all the info on my various DIY Guitar effects builds, amplifiers and guitars. Everything from a humble Ibanez tubescreamer to the holiest KLON Overdrive.

You may also find a few effects builds that I am looking to move on - usually in exchange for other effects/gear/cash. You can always check my ebay account to see what I've got up for grabs.

Have fun, enjoy the blog - Fred Briggs :-)


Feel free to get in contact with me about anything you see on this blog or with any general questions about guitars, amplifiers and effects, I'll be happy to answer! Just click the button above to email me directly or alternately my email address is fredbriggs2007 [at] googlemail [dot] com

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Sunday, 22 January 2012

Brunetti - Mercury

Brunetti are an Italian company who make some really great sounding amps and stompboxes. The Mercury Box is there overdrive pedal. Here's the description from the Brunetti website:

"Mercury Box is the new Brunetti overdrive/ distortion stomp box. A small metallic box holds together the qualities of the well-known CustomWork Mercury’s channel 2! It is endowed with “FET” technology to reproduce tubes behavior and dynamics as accurately as possible. Mercury Box is extremely versatile, you can move from clear and defined crunch sounds to hard rock “liquid” distortion which is always clean and never shapeless, very smooth and respectful of your instrument timbre, even at high gain levels. Controls are soft and sentive, but effective at the same time. They indeed interact thoroughly as in a real tube amplifier. Mercury Box arises from careful design and long lasting research of Marco Brunetti, and the outcome is innovative and technologically unique. It is not the upgraded clone of a well-know stomp box! These qualities make Mercury Box different, we are sure you will be impressed at first note!"

And a demo video of the Mercury in action (This is a clone built from the verified schematic below):

The chips are a MAX1044 or ICL7660 charge pump and a TL071 single opamp.

As the schematic shows the Mercury Box has a single op amp gain stage running into two jfet gain stages. Jfets do sound great as a clipping device. The whole circuit is powered at 18v via the charge pump, that adds headroom and dynamic range. All in all it's a pretty well designed circuit and it sounds neat too! One change I would make would be to replace the 22k drain resistors on the Jfet stages with 2 47k trim pots which would allow you to really dial in the sweet spots for maximum gain and sustain.

Here's the freestompboxes.org topic for reference: http://freestompboxes.org/viewtopic.php?f=7&t=9846


  1. Hi Fred, great stuff here.
    I have the original Mercury Box.
    In mine R20 is 4,7k and VR3 is 50 kOhm.
    It is a great sounding device but it's difficult to adjust the volume. At the beginning is nothing but after a short twist it's too loud. I've added a trim pot of 50 KOhm after VR3 and adjusted it to equal volume at mid settings of VR3.
    Best regards
    Otto from Germany

    1. Cheers for the info Otto, it'll be useful for others who fancy building this :-)

  2. I build this schematic from http://www.box.com/s/3ofp8pkkq9bov4uxkjrg
    Yes, it working well, simply to change 22K resistors (R9+R14) with 50K trimpots and i get smooth distortion or max gain from it. I have a pcb layout too from another webs forum, feel free to contact me and i'll send it by email. Thank's Fred, cheers from Indonesia :)


Comments are welcome on Revolution Deux. However, please do not spam links to unrelated sites - these comments will be removed! Thanks - Briggs.