Build Documents for Pan Galactic FX Mega Chorus
Please find BOM at the bottom of this document.
Please read the entire document before commencing build.
We Recommend starting with the smallest components first, the resistors and diodes, before moving onto sockets for the ICs, caps and transistors. Check the polarity of diodes and Electrolytic caps!
This PCB can be used with MN3007 BBDs which can work with up to a 15v supply, though we recommend using 12v at the maximum, or it can be configured to work with MN3207/8 BBDs which can only work up to an 8v supply, for which a space for a voltage regulator is provided.
- Connect BBDPwr to Vreg - Shown with Orange
if following the MegaChorus Schematic: - Connect BBD VDD to Vb – Shown with Yellow Or, Alternatively the Boss CE 2 Schematic shows:
- BBD VDD to GND – Shown in Blue (Experimental)
For MN3007 - R16A1 Should be installed, R16B1 Should be omitted.
If using MN3007 – You Must use MN3101 Clock If MN3007 is used
- 8v Regulator does not need to be installed, but RR1 is required instead
| No. | Ref | Value | Type | Notes |
|---|---|---|---|---|
| 1 | R1 | 10k | Resistor | |
| 2 | R2 | 47k | Resistor | |
| 3 | R3 | 12k | Resistor | |
| 4 | R4 | 12k | Resistor | |
| 5 | R5 | 47k | Resistor | |
| 6 | R6 | 10k | Resistor | |
| 7 | R7 | 1k | Resistor | |
| 8 | R8 | 12k | Resistor | |
| 9 | R9 | 47k | Resistor | |
| 10 | R10 | 10k | Resistor | |
| 11 | R11 | 1M | Resistor | |
| 12 | R12 | 1M | Resistor | |
| 13 | R13 | 10k | Resistor | |
| 14 | R14 | 10k | Resistor | |
| 15 | R15 | 10k | Resistor | |
| 16 | R16 | 10k | Resistor | |
| 17 | R17 | 10k | Resistor | |
| 18 | R18 | 100k | Resistor | |
| 19 | R19 | 10k | Resistor | |
| 20 | R16A1 | 56k | Resistor | Only Install for MN3007 |
| 21 | R16B1 | 56k | Resistor | Only Install for MN3207/8 |
| 22 | R20 | 10k | Resistor | |
| 23 | R21 | 12k | Resistor | |
| 24 | R22 | 10k | Resistor | |
| 25 | R23 | 390r | Resistor | |
| 26 | R24 | 330k | Resistor | |
| 27 | R25 | 4k7 | Resistor | |
| 28 | R26 | 10k | Resistor | |
| 29 | R27 | 100k | Resistor | |
| 30 | R28 | 10k | Resistor | |
| 31 | R29 | 330k | Resistor | |
| 32 | R30 | 10k | Resistor | |
| 33 | R31 | CLR | Resistor | |
| 34 | R32 | 470r | Resistor | |
| 35 | RR1 | 33r | Resistor | Install this if using MN3007 |
| 36 | and | NOT | installing | the voltage regulator |
| All The ollowing Resitors are part of the Clock/LFO Circuit | ||||
| 37 | CR1 | 100k | Resistor | |
| 38 | CR2 | CLR | Resistor | |
| 39 | CR3 | CLR | Resistor | |
| 40 | CR4 | 2k7 | Resistor | |
| 41 | CR5 | 33k | Resistor | |
| 42 | CR6 | CLR(2k2) | Resistor 2k2 indicated on original schematic | |
| 43 | CR7 | 10k | Resistor | |
| 44 | CR8 | 10k | Resistor | |
| 45 | CR9 | 10k | Resistor | |
| 46 | CR10 | 10k | Resistor | |
| 47 | CR11 | 10k | Resistor | |
| 48 | CR12 | 33k | Resistor | |
| 49 | ||||
| 50 | CR13 | 68k | Resistor | See |
| 51 | CR14 | 33k | Resistor | |
| 52 | CR15 | 47k | Resistor | |
| 53 | CR16 | 390r | Resistor | |
| 54 | CR17 | 470k | Resistor | |
| 55 | CR18 | 10k | Resistor | |
| 56 | CR19 | 10k | Resistor | |
| 57 | CR20 | 6k8 | Resistor | |
| 58 | CR21 | 6k8 | Resistor | |
| 59 | CR22 | 10k | Resistor | |
| 60 | CR23 | 4k7 | Resistor | |
| 61 | CR24 | 1k | Resistor | |
| 62 | CR25 | 10k | Resistor | |
| 63 | CR26 | 4k7 | Resistor | |
| 64 | CR27 | 4k7 | Resistor | |
| 65 | CR28 | 10k | Resistor | |
| 66 | C1 | 6n8 | FilmCapacitor | |
| 67 | C2 | 1n | FilmCapacitor | |
| 68 | C3 | 47n | FilmCapacitor | |
| 69 | C4 | 8n2 | FilmCapacitor | |
| 71 | C5 | 1u | FilmCapacitor | |
| 72 | C6 | 47n | FilmCapacitor | |
| 73 | C7 | 6n8 | FilmCapacitor | |
| 74 | C8 | 3n3 | FilmCapacitor | |
| 75 | C9 | 8n2 | FilmCapacitor | |
| 76 | C10 | 470p | FilmCapacitor | |
| 77 | C11 | 47n | FilmCapacitor | |
| 78 | C12 | 1u | FilmCapacitor | |
| 79 | C13 | 47n | FilmCapacitor | |
| 80 | C14 | 8n2 | FilmCapacitor | |
| 81 | C15 | 1n | FilmCapacitor | |
| 82 | C16 | 1u | FilmCapacitor | |
| 83 | EC1 | 10u | ElectrolyticCapacitor | |
| 84 | EC2 | 220u | ElectrolyticCapacitor | |
| 85 | EC3 | 100u | ElectrolyticCapacitor | |
| 86 | EC4 | 10u | ElectrolyticCapacitor | |
| The following aps all makup part of the clock/LFO circuit | ||||
| 87 | CC1 | 47p | FilmCapacitor | Depth Mod can be increased. 150p Highest Tested |
| 88 | CC2 | 470n | FilmCapacitor | |
| 89 | CC3 | 10n | FilmCapacitor | |
| 90 | CEC1 | 10u(22u) | ElectrolyticCapacitor | Experiment with different values - 1u on CE2 |
| 91 | CEC2 | 10u | ElectrolyticCapacitor | |
| 92 | CEC3 | 10u | ElectrolyticCapacitor | 100u has been suggested on forum |
| 93 | D1 | 1n4005 | diodes | Power Protection 1N5187 |
| 94 | D2 | LEDA | diodes | Bypass |
| 95 | D3 | LEDA | diodes | Triangle |
| 96 | D4 | LEDA | diodes | Triangle |
| The Following Diodes are part of the clock circuit | ||||
| 97 | CD1 | LEDB | diodes | Rate |
| 98 | CD2 | 1N4148 | diodes | |
| 99 | CD3 | 1n4148 | diodes | |
| 100 | CD4 | 1N4148 | diodes | |
| 101 | CD5 | 1n4148 | diodes | |
| 102 | Q1 | 2N3904 | transistors | 2n5088/9 |
| 103 | Q2 | 2N3904 | transistors | |
| 104 | Q3 | 2N3904 | transistors | |
| The Following Transistors form part of the clock ircuit | ||||
| 105 | CQ1 | 2N3904 | transistors | |
| 106 | CQ2 | 2N3904 | transistors | |
| 107 | CQ3 | 2N3904 | transistors | |
| 108 | CQ4 | 2N3904 | transistors | |
| 109 | CQ5 | 2N3904 | transistors | |
| 110 | IC1 | TL072 | integrated circuits | Any Typical Dual Opamp |
| 110 | IC2 | TL022 | integrated circuits | Use Low Power Op Amp for best results |
| 111 | IC3 | MN3208_BBD | integrated circuits | MN3207/8 OR MN3007 - SEE NOTES! |
| 112 | IC4 | MN3101_CLK | integrated circuits | MN3102 OR MN3101 – SEE NOTES |
| 113 | CIC5 | TL022 | integrated circuits | Use Low Power Op Amp for best results |
| 114 | REG1 | LM78L08 | 8v regulator | Install if using MN3207. Install Regulator OR RR1 if using MN3007 |
| 115 | BiasVR1 | 25k | potentiometers | Pot to Tune Bias Voltage for BBD |
| 116 | TuneVR2 | 50k | potentiometers | LFO Tuning |
| 117 | SineTrim3 | 47k | potentiometers | Sine wave shape trimmer can be omitted and pins 2 & 3 shorted. See Notes |
| 118 | CLR1 | 47k | -100k | potentiometers |
| 119 | Trim1 | 47k | -100k | potentiometers |
| 120 | Rate1 | B100k | potentiometers | Alpha |
| 121 | Shape2 | B100k | potentiometers | Alpha |
| 122 | Depth3 | B100k | potentiometers | Alpha |
| 123 | Delay4 | B500k | potentiometers | Alpha |
| 124 | Tone5 | B50k | potentiometers | Alpha |
| 125 | Blend6 | B10k | potentiometers | Alpha |
| 1 | Also | required | 2 | x |
| 1 | Bypass | Footswitch | ||
| LFO | F | |||
| Footswitch | Sine/Triangle | LFO | Selection |
Clea