Based on one of the most famous and boutique overdrives, the Knight Of tone takes to the limit the possibilities you can get out of this circuit; featuring many possible mods such as external presence control, internal charge pump, and external toggles to select in between the three modes, boost, overdrive, and distortion.
This circuit’s origins go back to 1991 when the engineers at Marshall were trying to recreate the classic Bluesbreaker amps’ tone from the ’60s on a pedal format. The result of that was a dual OpAmp based transparent overdrive with the same name as the legendary amp and with the same core design as the one we have here today in the Knight of Tone, as well as on many other boutique overdrives from Analogman’s King of Tone to JHS Morning glory and many others.
On the King Of Tone by Analogman, you got basically two Bluesbreakers circuits with different clipping options that allows you to set the pedal as an overdrive (Clipping on the feedback loop of the OpAmp), Distortion (after the OpAmp and before the tone control, pretty much like a Rat) or as a booster (Without any clipping option engaged)
For this design, we conceived the idea of taking all the things that make this circuit great and take it to the next level. We took many of the great functionalities of the King of tone but making them more user-friendly. For example, we replaced the internal DIP switches that select the diode mode with external DPDT switches, making dialing your tone much easier. Also, we did the same with Presence control, making it easier to cut through the mix.
Another mod included here is the internal Charge pump, which takes the 9v input and doubles it to 18v, giving it much more headroom and clarity. This can be easily bypassed, as’s explained in the Building Docs.
Also, we included another mod you can make if you want to add more gain to your build, but take in mind that the high gain goes better on lower voltages if you want to get a dirty tone out of it.
- Mode Switch
All these controls correspond to each side of the pedal.
For further analysis on this circuit take a look at this thread on Free Stomp Boxes Forum.