Before I got my FM3, I built a clone of the KOT. The FM3 model was so close that I couldn’t tell the difference. I put the pedal up on Reverb the next day.
Although Fractal didn’t model the clean boost or distortion, you can use the advanced settings to create the other two modes. Attached to this post are blocks for the distortion and clean boost modes. The King of Tone uses clipping diodes in an opamp feedback loop to create distortion. Each mode corresponds to a different selection of clipping diodes. All modes are symmetrical, i.e. uses the same diode/number of diodes for the positive and negative side of the wave:
- Overdrive: Two S1588 diodes
- Distortion: One MA856 diode
- Boost: No diodes
The ability to change diodes in the advanced tab is a very powerful tool, and, paired with the above information, will allow us to recreate the missing KOT modes.
For the distortion mode, we do not have the MA856 diode that Analogman uses. However, we do have the 1N914, which has essentially the same clipping properties as the MA856 (Vf ≈ .68). Selecting one 1N914 for both the positive and negative diode will give you the KOT distortion mode.
For boost mode, you want to have an arrangement that produces no diode clipping. There is not a "no diode" option, but there is a Blue LED option. Blue LEDs have a very high headroom (Vf ≈ 3.2), and require a hotter signal in order to start clipping. We can further raise the headroom by placing additional blue LEDs in series with the first one. One blue LED has a Vf of approximately 3.2 volts; increasing that to four blue LEDs will result in a Vf of approximately 12.8 volts, which is so high that it will not clip at all. This gives us our clean boost mode.