• These captures were originally done for a friend who owns the actual pedal and we wanted to see if we would be able to match its sound with LTspice plus NAM and also so that he doesn't have to plug in his physical pedal every time he wants to jam.
(Spoiler: We succeeded!)
• Settings are stated in the file titles (exact same settings done for two ATTACK modes: 6 and 8).
ATTACK 6 would translate to about position 4 on the actual pedal and Attack 8 to 6 (more info below).
These are typical settings for a modern metal sounding TS-style boost used to tighten up high-gain amplifiers.
Finally, I decided to adapt the "Fortin Mod", originally done for the Tube Screamer pedals, for the Precision Drive circuit. It adds a distinct flavor to the sound, with more saturation, less compression and considerably higher output.
• Slightly technical info (TLDR; some nerdy stuff, you can jump straight to notes if you are not interested):
The ATTACK capacitor values were spaced for 8 (instead of 6 in the original) distinct modes in my schematic to have a less abrupt tonal transition between them. These values range from 33 nF to 470 nF, as in the original. Of course, LTspice doesn't natively support rotary switches so I expressed the clipping circuit filter cap value as an equation that curve fits the input values from 1 to 8, to the correct output values from 33 to 470.
Custom SPICE models were used for the non-linear components (potentiometer curves, silicon diodes, LEDs, buffer transistors, OpAmps), either downloaded directly from the manufacturers' websites or created by extracting the values from their respective datasheets or real-life measurements.
Especially diode forward voltage curves, which I believe are the most important factors for simulating these kinds of pedals, were meticulously checked to match their real-life counterparts.
I am confident about the accuracy of the models used, because (apart from me checking each one's values and behavior individually) we matched the settings between the physical pedal and the schematic and we could not hear any difference at all!
These are the first NAM captures I've done using LTspice, and I can say the result is outstanding. LiveSPICE, which I've used in some of my previous NAM captures, is a great tool that can have many use cases. However, due to its simplified native models and real-time nature, it definitely has its shortcomings. A traditional SPICE simulation makes way more sense if we want to output an accurate WAV file that can be used to create a trained NAM file. The downsides of this are that it is harder to set up and way more time-consuming.
⚠️ Note: The output of the captures is at unity gain. You can always set the output at +2-3 dB for a more realistic, closer to the actual pedal's output. And for the 'Fortin Mod', you can set the captures to +6-8 dB for the authentic output of the mod (yes it is way louder than the stock version, but you can use it however you like).
⚠️ Note 2: These captures are NOT derived from the physical pedal but from circuit simulation done in a SPICE environment. I just want to be transparent about that and not mislead people. Of course that doesn't mean they can't sound just as good, provided they are done correctly.
⚠️ Note 3: This is a small pack. I don't promise anything but if enough people like it I might add more settings in the future. You can comment what settings you would like to see.
