Blue Grit

"Tube-like clean to low-gain drive with a bit of grit, a good fit for blues, country, and maybe classic rock."



The Blue Grit overdrive rack effect module compares more to a well-known DIY design rather than commercially-available pedals. It's tubey tone goes from mostly clean to mild overdrive, with controls that focus on the highs and presence.  Maybe best suited for country or blues, but gets close to some of the lower gain classic rock tones as well.



Blue Grit is based on a circuit called Blue Magic by J. Nagy.  It is meant to provide a glassy, tube-like, clean to low-gain boost with a little grit for blues.  It does that.  It has a reasonable range of boost (Volume) and clean to low drive.  But the other controls are all focused on high treble content - upper harmonics and noise.  Because of that, the other controls are very subtle in their effect, and then only if you are playing high treble material.  It is sort of like a clean-ish boost with Presence control.  We can definitely build it that way, but you might think some of the controls do nothing at all.  It can be bright, particularly with single coils and a Fender-style amp.

By default, we build a changed-up "More" version of the circuit.  It is still intended to provide a glassy, tube-like boost, and still has significant volume boost on tap.  Instead of covering clean to low gain, it covers clean to mid-gain, getting you from blues and country to some classic rock.  The Tone, and optional Air controls have been moved down to a range that is still best considered "presence", but a little more audible.  The Mid Boost range has also been expanded, but it remains subtle.

The range of controls in the More version still covers the original ranges, but they have been expanded.  That gives you slightly more range to work with, but the control is not as fine.

Both versions remain very similar in sound and range.  The More version is not a major change in tone from the original.  The most easily-noticed difference is the expanded range of gain.  The best part of the circuit is the boost and the low to mid range of the gain.  The remaining controls still have subtle effects, mostly in the high treble or "sparkle" range.



  • Blue Grit - compares to J. Nagy Blue Magic






  • Original Version - Select this option if you know the original version of the circuit and prefer that to our modified "More" version.  This option leaves off the "More" mods and goes back to original component values.
  • Air Control - At one end of the control, you get the full tone of the circuit.  As you adjust it, you start cutting back on highs.  The impact can be subtle.
  • Mid Boost Switch - This option allows you to switch between the original level of mids and a boosted level of mids.
  • Change Voltage - The effect normally runs at 9V.  This can be changed to 12V or 15V to provide more clean headroom.  This will result in a slightly lower level of distortion, which is already pretty low to start with.  If you are looking for more clean-ish boost and less drive, this may be of interest. 
  • Custom Components - The circuit uses a MOSFET BS170 and a JFET J201 transistors.  We use metal film resistors and a selection of capacitors that provide good tone and low noise. 


Front Panel

  • Volume
  • Tone
  • Drive
  • (optional) Air control
  • (optional) Mid Boost switch


Rear Panel

  • Audio In
  • Audio Out
  • On/Off Footswitch
  • On/Off Override
  • DC Power
  • DC Power LED


Module Width

  • 1.5" standard
  • 2" with options
  • 2" left wing module and 1.5" right wing modules are available for 3-4 control configurations


Power Consumption (aprox)

8 - 12mA


Base Configurations

Part # Description List Price
MOD-BGRIT Blue Grit module $199



Part # Description List Price
MOPT-BGRIT-ORIG Original Component Values $0
MOPT-BGRIT-AIR Air Control $19
MOPT-BGRIT-MIDS Mid Boost Switch $19
MOPT-BGRIT-VOLTS Change Voltage  $0
MOPT-BGRIT-CC Custom Components $0 - TBD



Part # Description List Price
MPT-BGRIT-CA Replacement pot, switch, jack, LED cable assembly $19
MPT-BGRIT-KNB Replacement control knob $2
MPT-BGRIT-PB Replacement power board $29
MPT-BGRIT-SB Replacement switching board $29