VFE Pedals Blues King



Blues King overdrive pedal, which is a clone of the Marshall Bluesbreaker overdrive circuit. I have added a number of extra features, plus upgraded the op amp to a NOS Raytheon RC4559N for increased fidelity and transparency. The added features are dual 3-way toggle switches to change the nature & amount of distortion. The top toggle switch is for soft clipping, and switches between symmetrical (dual 1S1588 clipping diodes), asymmetrical (1N914 x 1N4001), and a diode lift for a clean boost. The left toggle switch is for hard clipping, and switches between symmetrical (MA856), asymmetrical (dual 1N914 x single 1N914), and a diode lift for a clean boost. The 1S1588 & MA856 diodes were made popular by their use in Analogman's King of Tone pedal (which is also based on the Marshall Bluesbreaker). The right toggle switch changes the bass response of the circuit for those who want to fatten up single coils or use the pedal with a bass guitar. Internally, there are two additional controls. One tweaks the treble response, and the other is a little difficult to explain. One feature of the Bluesbreaker that separates it from the TS808 Tubescreamer is that it has a resistor in series with the clipping diodes. This reduces the overall compression and distortion of the circuit. The second trimpot I've added allows you to change the value of this resistance, making it possible to increase distortion & compression, or to reduce distortion & compression even more.

Here's a breakdown of the features of this pedal.


  • True mechanical bypass via 3PDT footswitch.
  • Large controls are standard Drive, Tone, Level.
  • Added 3-way switch to toggle between Symmetrical or Asymmetrical soft clipping, or a diode lift for a clean boost tone.
  • Added 3-way switch to toggle between Symmetrical or Asymmetrical hard clipping, or a diode lift for a clean boost tone.
  • Added 3-way switch to tailor the bass response (N = Normal, W = Warm, F = Fat).
  • Internal trimpots tailor the treble response and the amount of soft clipping.
  • High-quality 1% metal film resistors & 5% metal film capacitors, with carbon comp resistors in the signal path for those tone purists.
  • Switchcraft enclosed jacks
  • Higher-fidelity NOS Raytheon RC4559N op amp

The pedal is hand-built and housed in a small 2.4" x 4.4" enclosure. Accepts standard Boss-style negative tip 9-18V power supplies. A battery snap is installed, but the fit is tight due to the small enclosure.



  • DRIVE -- Controls the amount of gain in the circuit. The Blues King is a mild-to-medium gain overdrive pedal, so it has less gain available compared to The Scream.
  • TONE -- Simple & effective, the tone control operates like a treble-cut. Roll the TONE control counterclockwise to tame the high-end.
  • LEVEL -- Controls the overall output of the Blues King.
  • S - L - A -- The top 3-way toggle switch controls the clipping in the overdrive position.
    • S = Symmetrical MA856 silicon diodes
    • L = Diode Lift (no clipping)
    • A = Asymmetrical 1N914 silicon diodes
  • DIST -- The left 3-way toggle switch controls the clipping in the distortion position. The two clipping switches are separate & can be used simultaneously for harder overdrive tones.
    • A = Asymmetrical 1N34a germanium diodes
    • L = Diode Lift (no clipping)
    • S = Symmetrical 1S1588 silicon diodes
  • BASS -- This 3-way switch toggles the amount of bass roll-off.
    • F = Fat (most bass)
    • N= Normal
    • W = Warm (more bass)
  • INTERNAL CONTROLS -- There are two internal controls on the circuit board.
    • In the original circuit, there is a fixed treble roll-off filtering section. I have added a trimpot that can be turned to reduce the amount of treble cut, which is especially useful for clean boost or low-gain settings.
    • The second trimpot is in series with the overdrive clipping diodes, and is a unique feature of the original circuit. The extra resistance reduces the overall amount of clipping and compression, and this trimpot lets the musician fine-tweak the circuit for more or less distortion & compression.

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