CubuSynth Exhaust Expander Module - Build Guide

Introduction

This Build Guide is written for builders with experience in soldering and assembling PCBs. Due to the complexity of the build, the guide focuses on the steps that require special care or techniques. Therefore, not every component value is described and listed as a single step. To help keep track of the already placed components, print the BOM and cross out the parts you already soldered.

Tools Required

• Soldering iron (+wire)
• Side-cutter
• Nut wrench / driver M6, M8
• Helpful, but not necessary: Digital Multimeter, Helping (third) hand / PCB holder

Build Guide

STEP 1 (Main PCB): Diodes

Identify the 1N4148 diodes and place them. Orientation is important! Ensure the line on the diodes aligns with the stripe on the PCB silkscreen.

Components:

STEP 2 (Main PCB): Resistors

There are various methods for placing and soldering components. One approach is to select resistors of the same value, place them, turn the board over, and solder. Trim the leads and proceed to the next value. Alternatively, place all resistors and solder them from the top without turning the board. The next page shows a picture of all resistors in place.

Components:

Visual Aid Description:

Image shows the main PCB with various resistors and two 1N4148 diodes soldered in place, indicating correct orientation and placement.

STEP 3 (Main PCB): Ceramic Capacitors

1nF capacitors are marked as "102", and 100nF capacitors are marked as "104". Orientation does not matter for these components. Place them and bend the solder legs outwards to prevent them from falling when the board is turned. Solder all ceramic capacitors.

Components:

Visual Aid Description:

Image shows the main PCB with resistors, diodes, and ceramic capacitors soldered. The placement of components like C28, C29, C30, C12, C14, C16, C19, C25, C31, R135-R138, R141, R143-R144, R147, R153-R155, R167, R176-R177, R217-R226, R229-R233, and 1N4148 diodes is visible.

STEP 4 (Main PCB): Power Header

Components:

Turn the board over and place the Pin Header as shown. Use tape to secure it while soldering from the other side.

Visual Aid Description:

Close-up image of the underside of the main PCB showing the 2x5 pin header (H4) soldered in place. Text labels like "Power here!", "Don't connect", and "From Main Me" are visible near the header.

STEP 5 (Main PCB): Transistor

Place the 2N3904 transistor, ensuring its orientation matches the silkscreen outline on the PCB. Bend the two outer legs of each transistor inwards to prevent them from falling out when the board is turned. The footprint is small; focus on avoiding shorts by using minimal solder. Check solder joints with a magnifier or multimeter if unsure.

Visual Aid Description:

Image shows the main PCB with the 2N3904 transistor (labeled '2N3904') and associated resistors (R135, R136, R138, R141) and a diode (1N4148) soldered.

STEP 6 (Main PCB): IC Sockets

Components:

Orientation is crucial for ICs. The notch on the IC should face upwards, matching the PCB print. Secure the sockets using tape, placing another PCB on top, or bending two pins inwards to prevent them from falling when the board is turned. Solder all IC sockets.

STEP 7 (Main PCB): Toggle Switch & Pin Headers

Place the toggle switch in its designated spot. Take the 8-Pin Male Headers and Female Sockets, stick them together, and place them on the Main PCB with the female header downwards. Do not solder them yet. The correct placement of the switch and pin headers is shown.

Visual Aid Description:

Image shows the main PCB with IC sockets, resistors, diodes, and transistors installed. A toggle switch and 8-pin headers (male and female) are also shown in place, ready for soldering.

STEP 8: Control PCB Assembly

Place the control PCB on top of the main PCB, aligning the switch shaft with the large hole and ensuring the male header pins pass through their solder pads. Secure the switch with its nuts. Carefully turn the assembly over. Solder the switch first to hold the two PCBs together, then solder the pin headers on both sides.

STEP 9 (Control PCB): Resistors

After removing the switch nut and separating the PCBs, place and solder the resistors on the control PCB as illustrated.

Components:

Visual Aid Description:

Image shows the control PCB with resistors (R218, R219, R220, R221, R223, R224, R225, R226, R227, R228, R232, R233, R235) and LED13 soldered in place. Jacks (J36-J39, J42) and a toggle switch are also visible.

STEP 10 (Control PCB): LED

Components:

The LED orientation is important. The longer leg should go into the upper hole, with the flat side of the LED pointing down. Solder it flush to the PCB.

STEP 17 (Control PCB): Controls (Potentiometers & Jacks)

Place the potentiometers and jacks in their marked positions on the PCB, but do not solder them yet. The next page shows their placement.

Components:

Visual Aid Description:

Image shows the control PCB with potentiometers and jacks installed. The potentiometers are labeled for functions like EXT, AM, SEL1, SEL2, SUB/2, SUB/4. Jacks are labeled J36, J37, J38, J39, J42.

Final Assembly

Once all components are in place, position the front panel, ensuring all controls align with their respective holes. Fit nuts onto the potentiometers and jacks. Carefully turn the assembly over to keep components in place, then solder everything. Attach knobs, turning counter-clockwise first, and push them on so the marking points towards the left end of the surrounding circle.

STEP 18: Installing ICs and Final Check

Install the ICs onto the Main PCB, ensuring they are in their correct spots. Bend the IC legs inwards to form a 90-degree angle with the chip body. Verify orientation by matching the notch to the silkscreen or socket markings.

Check soldering for shorts or bad joints and fix them. Verify power pins for shorts using a multimeter. Fit the control PCB, ensuring the switch passes through its hole and pin headers connect properly. Tighten the switch nut. Fit the front panel, secure potentiometers and jacks with nuts, and attach knobs.

To connect the module, plug the 10-pin ribbon cable correctly into your CubuSynth Engine and the Exhaust while the rack is powered OFF. Ensure correct orientation (red stripe down). Then, turn on your case.

Visual Aid Description:

Image shows the main PCB with ICs (CD4013BE, TL074CN) installed in their sockets. The orientation of the ICs, indicated by a notch, is visible.

Support and Contact

CubuSynth cannot guarantee that every DIY module will work, but they will provide guidance through the build or assist with problems. For missing parts in DIY kits, contact CubuSynth for replacements. For build issues, contact them via the website contact form or email: cubusynth@gmail.com. To help identify mistakes, include quality pictures of your soldered PCBs (front and back).

Links:

• https://cubusynth.com/
• https://www.facebook.com/cubusynth
• https://www.instagram.com/cubusynth_modular/
• https://www.tindie.com/stores/cubusynth/
• https://www.etsy.com/shop/CubuSynth