The origins of this circuit goes back to 1991, when the engineers at Marshall where trying to recreate the tone of the classic Bluesbreaker amps from the 60’s 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 great this circuits and take it to the next level. We took many off the great functionalities of the King of tone, but making them more userfriendly, for example we replaced the internal DIP switches that selects the diode mode, with external DPDT switches, making dialing your tone much easier. Also we did the same with Presence control, making easier to cut through the mix.
Another mod included here is the internal Charge pump, that takes the 9v input and doubles it to 18v, giving this way much more headroom and clarity. This can be easily bypassed as it’s explained on the graphic bellow.
Also, we included here 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 wanna get a dirty tone out of it.
- Mode Switch
All this controls corresponds to each side of the pedal.