- Build Rating
Big thanks to @almondcity for generously providing the schematic & layout files!
@marksescon for his excellent & approachable writing on the whole dynamic sag/envelop detection rabbit hole!
Between the two circuits, it was a tedious week of turning trimmers…
This was my first time really going beyond RAT, Muff, Fuzz Face topologies and all the doom/stoner derivatives
Chuck’s JFET wisdom scattered across this forum and Mark Sescon’s blog were incredibly helpful (in figuring out what tf was going on with all the trimpots)
Now I love trimpots on the drain
Almondcity Dynamic JFET OD
I was originally planning on building the Mini, but I saw this in almondcity's shared gerbers folder...
Schematic can be found in almondcity's build report: https://forum.pedalpcb.com/threads/dynamic-jfet-overdrive.26218/
Mods:
Main values tweaks were increasing the caps - inline with Mark Sescon’s Mini Values
Also, C1M sub for C500K Bass control sounds a lot better to me
Q4 subbed for 2SK118 (bent leads to match pinout)
C14 seems to be the light/heavy switch on F*ck OD, Kintsugi has it on a cap blend(?)
Other components that affect sag character are in BOM
I've included values and sources from multiple iterations of SSBS JFET drive lineage, applicable to other Mini/Forncius OD builds at equivalent positions
Source for most the mods & circuit explaination: Mark Sescon's Blog Post on Dynamic Sag, and https://github.com/marksescon/themini and DEFX The Copulator Build Notes
Not pictured but I also added a LED clipping mod from the SSBS F*CK mountain (Modded Mini + Mountain dual pedal)
I figured the mod would work, since this design is derived from Mark Sescon's Kintsugi (which was in turn derived from the SSBS Mini drive section + modded F*ck OD sag section)
From FSB source: https://www.freestompboxes.org/viewtopic.php?p=299702&hilit=Fuck+Mountain#p299702
I made a diagram of the mod, let me know if its correct, seems to be working fine when I wired it up
The LED clipping mod may be applied to the PPCB Forncius as well(?) *will fact check*
(or any common source JFET design with similar dual gang drive control between the stages)
I am playing around with socketing different diodes, will report back with findings
Also, I accidentally made a pseudo Fy-2/octavish pedal, by accidentally swapping Gate and Source of Q4, is JFET common gate stage a thing in pedals?
https://www.ssguitar.com/index.php?topic=3732.0 seems to be a similar idea
DEFX Dilligaf
Graphics were based on the Infanem Faye Sing
Mods:
Germanium diode subbed with a BAT46
J201 subbed for 2SK118
Biasing the JFET was the hardest part, getting the appropriate drain resistor & JFET auditioning etc, (DEFX has the 4 pads to fit any JFET pinout! nice!)
Never using these style of box multi-turn trimmers again tho, takes way too many turns to sweep its entire range
Followed the rest of @gila_crisis mods & socket positions, except C12 = 2.2nF
https://forum.pedalpcb.com/threads/infanem-141g-and-driving-notion.25471/
I found C12 = 10nF to be the max value for retaining some ‘clang’ on the high side
The offboard spaghetti wiring was a regrettable decision… Thank god my first DEFX board happened to be for 125B
Also, first time going from working files to measuring out graphics and drill templates in CAD, which was intuitive transfering into the Tayda format
Thanks to everyone who wrote guides for Tayda’s UV printing, pot & jack spacing w 3d models, and measuring drill template co-ordinates!
@marksescon for his excellent & approachable writing on the whole dynamic sag/envelop detection rabbit hole!
Between the two circuits, it was a tedious week of turning trimmers…
This was my first time really going beyond RAT, Muff, Fuzz Face topologies and all the doom/stoner derivatives
Chuck’s JFET wisdom scattered across this forum and Mark Sescon’s blog were incredibly helpful (in figuring out what tf was going on with all the trimpots)
Now I love trimpots on the drain
Almondcity Dynamic JFET OD
I was originally planning on building the Mini, but I saw this in almondcity's shared gerbers folder...
Schematic can be found in almondcity's build report: https://forum.pedalpcb.com/threads/dynamic-jfet-overdrive.26218/
Mods:
Main values tweaks were increasing the caps - inline with Mark Sescon’s Mini Values
Also, C1M sub for C500K Bass control sounds a lot better to me
Q4 subbed for 2SK118 (bent leads to match pinout)
C14 seems to be the light/heavy switch on F*ck OD, Kintsugi has it on a cap blend(?)
Other components that affect sag character are in BOM
I've included values and sources from multiple iterations of SSBS JFET drive lineage, applicable to other Mini/Forncius OD builds at equivalent positions
Source for most the mods & circuit explaination: Mark Sescon's Blog Post on Dynamic Sag, and https://github.com/marksescon/themini and DEFX The Copulator Build Notes
Not pictured but I also added a LED clipping mod from the SSBS F*CK mountain (Modded Mini + Mountain dual pedal)
I figured the mod would work, since this design is derived from Mark Sescon's Kintsugi (which was in turn derived from the SSBS Mini drive section + modded F*ck OD sag section)
From FSB source: https://www.freestompboxes.org/viewtopic.php?p=299702&hilit=Fuck+Mountain#p299702
I made a diagram of the mod, let me know if its correct, seems to be working fine when I wired it up
The LED clipping mod may be applied to the PPCB Forncius as well(?) *will fact check*
(or any common source JFET design with similar dual gang drive control between the stages)
I am playing around with socketing different diodes, will report back with findings
Also, I accidentally made a pseudo Fy-2/octavish pedal, by accidentally swapping Gate and Source of Q4, is JFET common gate stage a thing in pedals?
https://www.ssguitar.com/index.php?topic=3732.0 seems to be a similar idea
DEFX Dilligaf
Graphics were based on the Infanem Faye Sing
Mods:
Germanium diode subbed with a BAT46
J201 subbed for 2SK118
Biasing the JFET was the hardest part, getting the appropriate drain resistor & JFET auditioning etc, (DEFX has the 4 pads to fit any JFET pinout! nice!)
Never using these style of box multi-turn trimmers again tho, takes way too many turns to sweep its entire range
Followed the rest of @gila_crisis mods & socket positions, except C12 = 2.2nF
https://forum.pedalpcb.com/threads/infanem-141g-and-driving-notion.25471/
I found C12 = 10nF to be the max value for retaining some ‘clang’ on the high side
The offboard spaghetti wiring was a regrettable decision… Thank god my first DEFX board happened to be for 125B
Also, first time going from working files to measuring out graphics and drill templates in CAD, which was intuitive transfering into the Tayda format
Thanks to everyone who wrote guides for Tayda’s UV printing, pot & jack spacing w 3d models, and measuring drill template co-ordinates!