Colourupter Assembly Guide

Safety Precautions, Warranty, and Disclaimer Improper soldering and handling of electricity can cause serious injury and damage to your property. Read and understand the instructions below before beginning your project. Follow the instructions, build carefully, and use the appropriate tools. Build at your own risk. DIY Recording Equipment, LLC is not responsible for any damage or injury resulting from the assembly or use of your kit. You are the manufacturer of your kit. It is your responsibility to turn this group of parts into a working piece of recording equipment. DIY Recording Equipment, LLC does not guarantee the success of your project and disclaims any Implied Warranty of Merchantability. Please visit the support forum for assembly support.
Damaged or Missing Parts All kits and parts are checked before being shipped to you. If something arrives damaged or if your kit is missing a part, please open a support ticket to inquire about a replacement. Missing parts will be replaced at our expense. Damaged parts should be returned for verification. If the part shows signs of use beyond what was necessary to determine that it was damaged, DIY Recording Equipment, LLC reserves the right not to replace the part.
Welcome to the Colourupter assembly guide.

Thank you for purchasing a Colourupter.

If this is your first DIY project ever, we recommend reading our Getting Started Guide.

Before you begin, check the revision of your PCB. If yours has the version number "v2.5" on the bottom you are on the correct page. If it does not, please follow the Colourupter mkI assembly guide.

Required Tools top

Soldering Iron
We recommend an adjustable-temperature station. The smaller, pencil-style ones that plug directly into the wall do not have enough power to create good joints consistently.

You can use 60/40 "leaded" solder or lead-free. We recommend 60/40 because it is easier and more forgiving to use.

Wire Cutters
A good pair will be sharp and have a fine point for cutting leads down right at the solder joint. Don't use a set of large cutters meant for household wiring.

Phillips Head Screwdriver
A #1 Phillips head screwdriver.

Optional Tools top

If you run into problems, a multimeter can come in handy. You can also use it to sort resistors.

Desoldering Pump
If you accidentally solder something in the wrong place, a desoldering pump can save the day.

500EXT Extender
A 500-series extender like the 500EXT will make testing and troubleshooting easier.

Room EQ Wizard (REW)
REW is an incredible piece of free measurement software for PC, Mac, and Linux. While REW is primarily known for measuring room acoustics, it's also a powerful tool for measuring analog gear. Download and install the latest version at the Room EQ Wizard website.

Component Sorting Sheet top

To identify and keep track of every part in the kit, download and print the Component Sorting Sheet (PDF).

Standoffs, Header, and IC Socket (Bag 1) top

Insert Standoffs top

Note that there are two different ends on the plastic standoffs. The locking end has tabs with a right angle to prevent them from being removed after installation, while the non-locking end has smooth tabs. Insert the locking ends of the standoffs from the bottom of the PCB.

Populate 8-Pin Header top

Insert the 8-pin header into the holes marked “CON1.” Make sure to place the short, silver pins through the bottom of the PCB so that the PCB rests on the black plastic posts. Solder the header from the top of the PCB and do not trim the leads afterward.

Tape and Solder IC Socket top

Insert the IC socket so that the notches on the sockets align with the markings on the PCB. Secure in place with tape. Then flip the PCB over and solder in place. Remove the tape.

Resistors (Bag 2) top

Bend Resistors top

Bend the resistor leads 90 degrees at the body so they can be inserted into the PCB.

Sort Resistors top

Resistor values are identified by colored bands on the body of the resistor. To sort resistors, use our Resistor Color Code Calculator or test them with a multi-meter set to read resistance. (Pro tip: to measure resistors quickly you can remove the probes from your multi-meter and place the leads of the resistor directly in the probe sockets.)

Place Resistors top

Place the resistors into their respective positions on the PCB. As you place each resistor, bend its leads against the bottom of the PCB so that it stays in place during soldering.

Solder Resistors top

Solder the resistors to the PCB. Observe good soldering technique: heat the pad and lead for 2-3 seconds, apply a small bit of solder, and continue to heat the pad for another 2-3 seconds. The finished joints should be shiny and should have just enough solder to cover the pad entirely.

Trim Resistors top

Use clippers to trim away the excess leads. Clip as closely as possible to the joint without clipping the joint itself.

Capacitors, Vactrol, and Trimpot (Bag 3) top

Populate Capacitors top

Place the capacitors in their respective positions. The capacitors are not polarized and therefore can be placed in either direction. Solder then trim the leads.

Populate Vactrol top

Next, we'll place the component at the heart of the Colourupter's sound: the vactrol, or resistive opto-isolator. The vactrol's orientation is indicated by the lead spacing; place the vactrol with the labeling on top and the closer leads towards the center of the PCB. Bend the leads, solder, and trim.

Populate Trimpot top

Populate the trimpot in the orientation marked on the PCB. Leave the trimmer alone for right now, we will set it in another step.

IC (Bag 4) top

Place IC in Socket top

The leads of the IC must be slightly bent to fit perfectly into the socket. Press one row of leads against a flat surface until they form a 90-degree angle with the body of the IC. Then do this for the other row.

IC polarity is indicated by a dot or notch on one side of the body. Align this side with the notch in the socket. Place the IC in this direction, and press it completely into the socket.

Final Checks top

    Before you wrap up, check the following things:

  • Capacitor orientation: Is the stripe on the cap on the opposite side from the "+" marking on the PCB?
  • Resistors: Are all the resistors in the correct positions?
  • IC orientation: Does the dot/notch on the IC align with the notches on the socket and PCB?
  • Diode orientation: Do the stripes on the diode match those on the PCB?
  • Soldering: Is every solder joint shiny and clean? If one is cloudy or misshapen, try reheating it for 8 seconds and adding a tiny bit more solder.
  • Trimming: Are all of the excess leads trimmed down as close to the joint as possible?

Calibration top

No two vactrols is exactly alike. So to ensure predictable behavior and acceptable stereo matching, we need to calibrate the Colourupter. If you are using the Colourupter in a 500-series rack, the following steps will be easier with an extender like the 500EXT.

Set Up for Testing top

Download and install Room EQ Wizard on your computer. In Preferences chose your audio interface for the Input and Output Device and set the Input and Output to the left/channel 1.

Connect the Colourupter to the left/channel 1 of your interface.

Check Unity Gain top

Set your Colour host so that the Colour section is engaged but all of the Colours are bypassed. For example, on the Colour Palette mkII, the IN switch should be in, but all Colour switches should be out. If your host as a trim, set it to unity gain.

In REW open the Generator module and set it to:

  • Tones, Sine
  • Frequency Hz: 1000
  • -12dBFS

Push the green play button and open REW's Levels module. Make sure the signal is coming back into the input at or very close to -12dBFS. This is unity gain. If you are not getting unity gain, check your connections.

Calibrate Colourupter top

Once you've have confirmed your Colour host passes unity gain, engage the Colourupter and set the Colour knob to 12 o'clock. You should notice that the input to REW is now a bit lower.

Use a screwdriver to adjust the VR1 trimpot until the level at the input is -15dBFS for 3dB of gain reduction. This will ensure that there is a moderate amount of compression at 12 o'clock on the Colour dial. If you would like the Colourupter to be more subtle, adjust for less gain reduction (higher input level). If you want your Colourupter more aggressive, adjust it for more gain reduction (lower input level).

Finished! top

All good? Congrats on finishing your build! Have a question or problem? Drop us a line.

Help Us Improve top

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