Super Nova Distortion The Super Nova is a reworking of the Marshall Guv'nor circuit. It uses the same gain structure as its parent design but is EQ'ed quite differently. The basic tone from the gain stages is a little more focused on the mid frequencies than the original. Clipping diodes are MOSFETs instead of LEDs. Finally, instead of a passive TMB tonestack there's a very responsive Baxandall tonestack. It works well with mid heavy blues rock and hard rock leads to crushing scooped thrash and death metal rhythms.. Finally the on board charge pump allows the unit to operate at 18V reducing opamp clipping and increasing head room. Pro tip: the Super Nova can be used as a standalone preamp into a power amp for live use or into a recording interface coupled with an impulse response for recording. License information Please note that the license for the Super Nova is different from most other Nucleon projects. Specifically, it is prohibited to produce commercial pedals with the Super Nova PCB. Please respect this. This project is for personal (DIY) use only. Commercial (re)selling or distribution of the PCB, its design layout or this build document is prohibited. These materials are not to be sold as part of a kit.. Construction and use of the PCB and project information is at your own risk. Nucleon FX cannot be held accountable for any damages to equipment or yourself. 2017 Nucleon FX 1
BOM Resistors Capacitors R1 2M2 C1 22n R2 1k C2 1n R3 1M C3 100p R4 1k C4 270-330n R5 10k C5 100n R6 330k C6 390p R7 22k C7 68n - 1u R8 22k C8 18-22n R9 22k C9 2n2 R10 18k C10 390p R11 18k C11 100n R12 47k C12 100n R13 47k C13 100u R14 100k C14 100n MLCC CLR 3k3-10k C15 100n MLCC C16 10u C17 10u Diodes and Controls misc D1 1N5817 GAIN 100 kb D2, D3 1n914 LEVEL 100 kb Q1, Q2 2N7000 BASS 50 kb - 100 kb TREBLE 50 kb - 100 kb Opto TLP222G IC 1, IC 3 TL072 Bypass DPDT Stomp IC2 See notes 2017 Nucleon FX 2
Schematic 2017 Nucleon FX 3
NOTES IC2 This IC generates a -9V supply for the split rail design. I suggest using a socket here also. Pick one of the ICs below. I've not found a bullet proof recipe. I've had seemingly identical builds where one worked well with the 7660S while the other one needed the 1054. In other words: YMMV. Chip BST pads Comments ICL7660S Jumper with wire of 0Ω resistor Cheap and can work, sometimes induces audible high pitched whine TC1044 Jumper with wire of 0Ω resistor Use as improvement over 7660S if that generates audible whine LT1054 Leave open Best performance, highest current consumption and expensive Tone Controls The Super Nova tone control is a Baxandall type filter that consists of a Bass and Treble shelf filter. The two filters cross over in the mid frequencies, allowing a mid-cut or boost centered around 720 Hz. This is a more flexible setup than might first appear. On the maximum settings there is about 6 db of boost or cut available. This is a modest amount but ensures a useable range of the controls. R12, R13 and C10 are unusual additions to the standard Baxandall. They help control the boost on the outer limits of the shelfs by squashing the boost on frequencies below 80 Hz and progressively lowering the boost above 3.5 khz. This again results in a more useable range of the controls, keeping mush and fizz in check. It also increases stability of the circuit, preventing stressing out the opamp. You may choose to omit them. Using 50k pots give a maximum boost of about 6.5 db at the outer frequencies of the range. A 100k pot add another 3 db or so to that if you need it. C4 and C7, 11, 12 The suggested value for C4 is either 270n or 330n, which corresponds to 590 Hz and 482 Hz respectively as the bass roll off frequency for the first amplification stage. Both work well, adjust to taste. Paradoxically, if you tune your guitar down a lot, a higher roll off frequency can keep things tight instead of muddy. C7, C11 and C12 can really be any cap value high enough to pass all frequencies. I suggest 68n for C7 and 100n or higher for C11 and C12. The exact value doesn't matter that much, so don't fret if you haven't got everything in stock. Substitutes up to 1 uf will work fine. Board Mounted Pots Use board mounted pots and tag them to the PCB by soldering only one leg at first. Fit the PCB to the enclosure and solder the remaining legs. Then reflow the first leg to relieve any tension from it. Put some thick double sided tape on the back for isolation. 2017 Nucleon FX 4
Capacitor types I roughly follow these guidelines for capacitor size when designing the PCB: smaller than 1nF: Multi Layer Ceramic (MLCC) for filtering smaller than 1nF: WIMA box caps in audio path 1nF - 10nF: Whatever I have around, usually 'greenies' or MKP box caps 10n - 1u: Panasonic ECQ-V in audio path 100n - 1u: MLCC for power filtering1u - 470u: Electrolytics This is mostly due to what's available in my personal stock. You can deviate from this. The only exception is the use of MLCC caps for filtering power lines. These do a better job than film caps. Wiring JI - tip of input jack JO - tip of output jack G - sleeve of output jack SW1 - center pad to center lug Outer pads to outer lugs 9V - sleeve of power jack G2 - center of power jack SW2 - one pad to centerlug Other pad to outer lug (one lug unused) Bypass DPDT Two sets of three (1 + 2 + 3 and 4 + 5 + 6) corresponding to columns on a DPDT switch. 1 and 4: top lug 2 and 5: center lug 3 and 6: bottom lug 2017 Nucleon FX 5
Drill Template Cover a 1590B in painters tape. Print this page at 100% scale and stick the template on top of the tape with some glue or tape. Double check alignment with the PCB before drilling. Drill the pot holes with a diameter 8 mm (one size larger than required) so you have some wiggle room. [Drill template coming soon] 2017 Nucleon FX 6