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MAELSTROM BASS DRIVE

1

PROJECT NAME

MAELSTROM

BASED ON

EFFECT TYPE

PROJECT SUMMARY

DOCUMENT VERSION

Darkglass

®

 Microtubes

®

 B3K

A CMOS-flavored bass overdrive with tones spanning across decades, from vintage warmth to modern
bite and aggression.

Bass overdrive / distortion

1.0.0 (2022-11-11)

BUILD DIFFICULTY

Intermediate

This documentation is for the 

kit

 version of the project. If you purchased the PCB by itself, please 

use the 

PCB-only version

 of the documentation instead. The circuit is the same, but the instructions 

are completely different due to the specialized parts and assembly methods used in the kit.

IMPORTANT NOTE

VOLUME

BASS DRIVE

DRIVE

9V

BLEND

TONE

LOW

HIGH

MAELSTROM

Summary of Contents for MAELSTROM

Page 1: ...sion Bass overdrive distortion 1 0 0 2022 11 11 BUILD DIFFICULTY Intermediate This documentation is for the kit version of the project If you purchased the PCB by itself please use the PCB only version of the documentation instead The circuit is the same but the instructions are completely different due to the specialized parts and assembly methods used in the kit IMPORTANT NOTE VOLUME BASS DRIVE ...

Page 2: ... Sockets ICs 13 Transistors 14 Capacitors Non Polarized 15 Wire Headers 16 Capacitors Polarized 17 Footswitch PCB 18 Input Output PCB 19 Enclosure Layout Panel Mounts 20 Enclosure Layout Panel Mounts Cont 21 Enclosure Layout Main Footswitch PCBs 22 Enclosure Layout Input Output PCB 23 Final Testing Assembly 24 Schematic 25 Full Parts List 26 Troubleshooting Information 27 Support Resale Terms 28 L...

Page 3: ...to learn a few things along the way This will take time Plan on about two hours start to finish It may take even longer if it s your first time building Don t rush it If you find yourself getting frustrated or overwhelmed take a break and come back in a couple of hours or the next day No direct technical support is offered There are several DIY forums and Facebook groups with thousands of members ...

Page 4: ...Missing Parts form Film Capacitors NAME QTY 1n 2 2n2 3 4n7 1 22n 6 100n 2 220n 2 1uF 2 Electrolytic Capacitors NAME QTY 47uF 1 100uF 1 220uF 1 MLCC Capacitors NAME QTY 22pF marked 220 2 220pF marked 221 1 680pF marked 681 1 100n marked 104 1 Transistors NAME QTY J201 with PCB adapter 2 Resistors NAME QTY 100R 1 1k 1 3k3 2 6k8 2 10k 6 22k 3 33k 1 47k 1 100k 3 200k 1 330k 1 470k 3 1M 7 Diodes NAME Q...

Page 5: ...ck 0 6 2 Lock washer jack 0 5 thin 2 Enclosure 1 Enclosure screws 4 PCB main circuit 1 PCB footswitch 1 PCB input output DC 1 Switches NAME QTY Toggle switch SPDT on off on 2 Mounting nut toggle switch 0 36 2 Lock washer toggle switch 0 4 2 Dress nut toggle switch 0 375 2 Stomp switch 3PDT 1 Mounting nut stomp switch 0 6 2 Lock washer stomp switch 0 6 1 Dress nut stomp switch 0 77 1 Wiring NAME QT...

Page 6: ...ee solder NEEDLE NOSE PLIERS These are used for bending leads on components and other general uses Use the smaller type with a tip that s approximately 0 05 1 25mm wide FLAT SCREWDRIVER SMALL This is used for tightening the set screws on the knobs The tip should be no more than 0 1 2 5mm wide DIGITAL MULTIMETER DMM Most cheap ones in the 10 30 range are fine for what we re doing Make sure it has a...

Page 7: ...APACITOR SCHOTTKY DIODE IC SOCKET TRANSISTOR WITH ADAPTER RECTIFIER DIODE TRANSISTOR OR JFET Not polarized Color may vary by brand and type Some Schottky diodes also look like this Polarized The positive side is marked Polarized The negative side is marked Some voltage regulators also look like this The pins will be soldered to the adapter during kit assembly Charge pumps and delay chips also look...

Page 8: ... SWITCH POTENTIOMETER SINGLE FOOTSWITCH POTENTIOMETER DUAL MOUNTING NUT MOUNTING NUT MOUNTING NUT MOUNTING NUT DRESS NUT OUTER WASHER DRESS NUT OUTER WASHER KNOB LOCK WASHER LOCK WASHER LOCK WASHER LOCK WASHER DIAMETER 0 54 13 7mm DIAMETER 0 36 9 1mm DIAMETER 0 44 11 2mm DIAMETER 0 5 12 7mm DIAMETER 0 6 15 2mm DIAMETER 0 375 9 5mm DIAMETER 0 475 12mm DIAMETER 0 5 12 7mm DIAMETER 0 4 10 1mm DIAMETE...

Page 9: ...nt to work in layers from shortest components i e lowest profile to tallest so that when the PCB is upside down everything is making contact with the work surface and is held in place Generally speaking you should populate the components in this order 1 Resistors 2 Diodes 3 IC sockets 4 MLCC capacitors 5 Film capacitors 6 Transistors 7 Electrolytic capacitors Not all of these component types are i...

Page 10: ...10k R30 100R RPD 1M LEDR 10k Using the parts list above populate the resistors by pushing them through the holes and bending the leads outward at an angle to hold them in place Resistors are not polarized so they will work in any direction Turn the board upside down to keep the components held in place while you solder Don t try to do all of the resistors at once You ll want to stop periodically f...

Page 11: ...ES PART VALUE D1 1N5817 D2 1N914 D3 1N914 Next you ll populate the diodes Diodes are polarized so make sure to identify the polarity band which indicates the cathode or negative side and match the band to the footprint on the PCB ...

Page 12: ...s the polarized capacitors This information is just listed here for reference The legs of the ICs are bent outward slightly during manufacturing so they ll need to be bent back inward before they can be inserted into the sockets It s easiest to do this by laying the IC legs against the table and bending the body itself so all four legs on the side are straightened out at once Then flip it and do t...

Page 13: ... soldered to the adapter Once the pins are installed the JFETs can be soldered to the PCB like any other normal component Be very careful to line up the D S G labels with the markings on the PCB or the effect will not work The component side of the PCB adapter should face upwards toward the toggle switches STEP 4 Solder the pins including the reverse side if needed Then using wire cutters clip the...

Page 14: ...film capacitors For these the value is printed on the top rather than the side C8 C10 C14 and C16 are blue MLCCs taped to cardboard The value is written on the cardboard C26 100n MLCC is always yellow It can be hard to read the code since it s so small so it s easier to identify this one by color PART VALUE C1 100n film C2 1n film C3 220n film C4 22n film C5 22n film C6 22n film PART VALUE C7 22n ...

Page 15: ...tors as shown above These have a polarity pin so as long as they are pressed all the way down there s only one possible way to install them They do fit pretty tightly in the holes though so press firmly There s also a 4 pin header on the I O board that we will do in a later step ...

Page 16: ...e polarized i e they will only work in one direction so note the vertical mark that indicates the negative side The longer leg is positive and fits in the square pad These are the last of the on board components Now is the time to go back to page 12 and insert the ICs into the sockets PART VALUE C23 100uF electro C24 47uF electro C25 220uF electro ...

Page 17: ...a later step PARTS 3 strand wire assembly 2 4 strand wire assembly STEP 3 Then solder the wires from the top This is the trickiest part of the whole build You want to solder the pads without touching the iron to the wires themselves and risking burning through the insulation It helps to use a sharp or narrow tip on the soldering iron STEP 2 Next bend the wires back upward and fit the ends of the w...

Page 18: ...an do them all at once before flipping and soldering After you ve soldered everything make sure to snip the leads on the I O jacks as close as possible to the PCB There s not a lot of clearance between the bottom of this board and the top of the main PCB once everything is in place and you don t want the pins to short against anything on accident PARTS Input output jacks DC jack Wire header ...

Page 19: ... Wrap a rubber band around it to use as a grip when tightening Do not use metal tools on it or you run the risk of scratching or denting it You ll need to hold the bezel in place when tightening the nut Be aware that the bezel is fairly sharp Try using a rubber band for grip instead of just pressing your finger against the bottom The LED will just sit loosely inside the bezel for now POTENTIOMETER...

Page 20: ...NG NUT MOUNTING NUT LOCK WASHER TOGGLE SWITCHES The dress nut acts as a mounting nut unlike the footswitch dress nut Use flat nose pliers on the flat sides of the nut to tighten securely 125B 100kC 100kA FOOTSWITCH BEZEL LED SPDT on off on SPDT on off on 100kB 100kB ...

Page 21: ...ce the main PCB on top of the potentiometers and toggle switches as in the diagram to the left You may need to adjust the position of the potentiometers and toggles slightly if they are not aligned straight Once all of the pins are through and the PCB is laying flat solder each of the pins from the top being careful not to touch any of the surrounding components with the soldering iron After you v...

Page 22: ...f the enclosure as shown Note the use of two mounting nuts on each of the jacks one inside and one outside The inner nut acts as a spacer to set the DC jack flush with the outside of the enclosure The inner nuts should be threaded as far down as they can go 125B MOUNTING NUT LOCK WASHER OUTER WASHER MOUNTING NUT ...

Page 23: ...sembly Turn the shafts all fully counter clockwise then put on the knob and rotate until the indicator line is aligned with the dot on the enclosure that shows the zero point Affix the knobs to each of the potentiometer shafts as shown in the diagram below Using a small flat head screwdriver no more than 0 1 2 5mm in diameter tighten the set screw until it presses against the shaft of the potentio...

Page 24: ...VB 100k 33k 680pF 22n GND VC GND CD4049UBE CD4049UBE CD4049UBE CD4049UBE CD4049UBE 10k 22k TL072P TL072P GND VA 2n2 2n2 GND 22k 47k 2n2 1n GND VB 1uF 1k 100k GND 100kB D1 C25 VOLUME 1 2 3 1 2 3 DRIVE BLEND 1 2 3 C26 RPD 2 3 1 HIGH 2 3 1 LOW C1 R1 R2 IC1A 2 3 1 8 4 6 5 7 IC1B R28 R29 R30 C23 C24 C2 R3 R4 Q1 R5 C3 Q2 C4 R6 R7 R8 C5 R9 C6 R10 C7 R11 C8 R12 C9 R13 2 3 1 IC2A 8 4 6 5 7 IC2B R14 C10 R15...

Page 25: ...pF MLCC C11 4n7 film C12 22n film C13 220n film C14 22pF MLCC C15 1uF film C16 680pF MLCC C17 22n film C18 2n2 film PART VALUE C19 2n2 film C20 2n2 film C21 1n film C22 1uF film C23 100uF electro C24 47uF electro C25 220uF electro C26 100n MLCC PART VALUE R17 470k R18 10k R19 1M R20 100k R21 33k R22 10k R23 22k R24 22k PART VALUE R25 47k R26 1k R27 100k R28 10k R29 10k R30 100R RPD 1M LEDR 10k Res...

Page 26: ...his way the probe stays in place without needing to use alligator clips The circuit must be fully installed in the enclosure for this to work Then touch the red probe to the first leg of IC1 and read the voltage Note that IC pins are labeled counter clockwise from the upper left as shown in the diagram to the right These baseline voltages are taken using a 9 6V supply Your measured voltages won t ...

Page 27: ...bsite There is no guarantee that we will be able to join the discussion and help solve your problem but this improves the chances It benefits the whole community if the troubleshooting process is public because then people who have the same issue in the future may come across it when searching And if you do get help remember to pay it forward The best way to learn new skills is to help others Even...

Page 28: ...nly under fair use It is not an endorsement of this product by the trademark holders These kits are intended to be built by the customer Aion FX is not responsible for language that may be used by the customer in the marketing or resale of the finished product All content and graphics in this document are original works and are copyrighted by Aion FX and may not be used without permission DOCUMENT...

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