Colourupter Assembly Guide
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Table of contents
- Required Tools
- Optional Tools
- Component Sorting Sheet
- Standoffs and Header (Bag 1)
- Insert Standoffs
- Populate 8-Pin Header
- Tape and Solder IC Socket
- Resistors (Bag 2)
- Bend Resistors
- Sort Resistors
- Place Resistors
- Solder Resistors
- Trim Resistors
- Capacitors, Vactrol, and Trimpot (Bag 3)
- Populate Small Capacitors
- Populate Vactrol
- Populate Trimpot
- Populate Large Capacitors
- IC (Bag 4)
- Place IC in Socket
- Final Checks
- Download and Install Room EQ Wizard (REW)
- Connect Colourupter to Audio Interface
- Check Unity Gain
- Calibrate Colourupter
Required Tools top
We recommend an adjustable-temperature station, such as the Weller WLC100.
You can use 60/40 "leaded" solder or lead-free. We recommend 60/40 because it flows better and is easier for beginners to use.
You'll need a pair of good "snips" for cutting of the excess leads after soldering.
Phillips Head Screwdriver
A #1 Phillips head screwdriver.
Optional Tools top
If a problem needs solving, a multimeter can come in handy. You can also use it to sort resistors.
If you accidentally solder something in the wrong place, a desoldering pump can save the day.
Component Sorting Sheet top
To identify and keep track of every part in the kit, download and print the Component Sorting Sheet (PDF).
Standoffs and Header (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 sorting made easy! Enter a value to find the color bands, or enter your color bands to find the resistor’s value. Type in the value of the resistor you need and this tool will show you the corresponding color code.
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 Small Capacitors top
Place the smaller capacitors in their respective places. These 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.
Populate Large Capacitors top
These capacitors are polarized, so they must be placed in a certain direction. The positive lead is slightly longer, while the negative lead is marked with a stripe on the body of the capacitor. Place the capacitors with the positive lead in the pad next to the "+" marking on the PCB. Double check their orientation, then solder and trim.
IC (Bag 4) top
Place IC in Socket top
The leads of the IC must be slightly bent to fit perfectly into the sockets. 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:
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.
Download and Install Room EQ Wizard (REW) top
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.
Connect Colourupter to Audio Interface top
Insert the Colourupter into a Colour socket in a piece of gear hooked up to your audio interface. For the easiest setup with REW, connect the Colorupter to left/channel 1 of your interface.
Set your Colour host so that the Colour section is engaged but all of the Colours are bypassed. For example, on the Colour Palette, the IN switch shoudld be in, but all Colour switches should be out. If your host as a trim, set it to unity gain.
Check Unity Gain top
Set REW preferences so that REW is using your audio interface and is using the left/channel 1 input and output. Then open the Generator module and set it to these settings:
- Tones, Sine
- Frequency Hz: 1000
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. If you are not getting unity gain, check your connections.
Calibrate Colourupter top
Once you've have confirmed your Colour host is passing unity gain, engaged the Colourupter and set the Colour knob to 12 o'clock. You should notice that the input to REW has changed a little bit and is no longer at unity gain.
Now 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).