OLA5 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 OLA5 Assembly Guide

Thank you for purchasing a OLA5 Opto Compressor Kit (Available Summer 2018)!

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

Table of Contents

Required Tools

You'll need the tools below to complete this build.

Soldering Iron
We recommend an adjustable-temperature station, such as the $40 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.

Phillips Head Screwdriver
A #1 Phillips head screwdriver.

Wire Cutters
You'll need a pair of good "snips" for cutting of the excess leads after soldering.

Optional Tools

These tools aren't strictly necessary but can make your build a bit easier.

A bit of clear tape will help hold some tricky components in place for soldering.

Standard, needle-nose pliers.

If you find the color bands on resistors a bit hard to read, you can use a meter to sort them with absolute confidence.

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

Place Resistors

Solder Resistors

The resistors are sorted into three sub bags in order of their part numbers on the circuit board. We recommend sorting, placing, and soldering one bag at a time to reduce mistakes. Note that R2 is a jumper and will be populatd in the next step.

Place Jumper for R2

Use one of the excess resistor leads to create a "0 Ohm" resistor for R2. Bend the lead and solder it to the PCB just like a component.

Place Sockets and Headers

Place IC Sockets and Headers

Place the sockets and headers on the motherboard. Use some tape to hold them in place as you solder the first joint. If the part is not mounted correctly after the first joint, heat the joint while pushing the part in from the other side of the PCB. Keep holding onto the part until the joint has cooled, then solder the rest of the pins.

Orient CON2 so that the side with a notch out of the plastic is facing away from the card edge.

Place Jumpers

Place two of the three jumpers on CON1 in the "MOD" positions for the modern output.

Place the third jumper on CON3 to set the LIMIT ratio. You can always change this and the output setting later.

Place Small Caps, LEDs, and Fuses

Place Sub Bag 1

Caps CB1-CB8 and fuses F1 and F2 are not polarized.

Pin 1 on the RA1 resistor array is marked by a dot. Align this dot with the dot on the PCB.

The positive lead of the LEDs 1 and 2 is indicated by a longer lead. Place this lead in the hole marked "+".

Place Sub Bag 2

The 100pF caps C3, C7, and C11 are not polarized.

The 22uF caps C8 and C10 are polarized. The positive lead is longer and is marked with a "+".

Place D1-D3 so that the black stripe on the body matches the white line on the PCB.

Place Sub Bag 3

None of the caps in this bag are polarized.

Place Q1 so that the side with the writing faces the bottom of the PCB.

Place LED

The positive lead of LED5 is longer. Flip the board over and place the LED from the bottom of the board. Insert it until the flat part of the leads and then bend it toward where the front panel will be.

Place Large Caps

Place Caps

C4, C6, C19, and C20 are not polarized.

The remaining caps have a band on the side of the body to indicate the negative lead.

Place Potentiometers and Switches

Place Switches

Place the caps on the switches first. Then place and solder them.

Place Potentiometers


Place Standoffs and Socket


Assemble Daughter Board

Place Sub Bag 1


Place Switches and Bracket


Solder LED Board to Daughterboard

First place the straight end of the right-angle header, solder, and trim. Then place the bent end in the daughterboard and solder.

Place LEDs in PCB

The flattened side of the LED on the PCB silkscreen indicates the negative terminal, which corresponds to the shorter leg on the LED.

Place LEDs in Front Panel

Place a piece of low tack tape over the LED holes in the front panel. Then place the daughterboard in the front panel and fasten it with a screw from bag #9. Press down on the tape to make sure that all of the LEDs sit flat and flush with the front panel.

Solder LEDs

Solder the LEDs and trim the leads, then remove the front panel from the daughterboard.

Attach DB to MB

Place the 12-pin header in the CON5A socket with the longer ends going into the socket. Now place the DB over them so the shorter leads go through CON5B from below. Screw the DB to the standoffs and solder CON5B.

Assemble Optos

Solder LEDs and LED Boards


Place Sockets


Place Standoffs and Tubes

Screw in the four standoffs for each opto from below the motherboard. Then place the black tubes over the LED pcbs.

Place LDRs and Headers


Solder LDR and Headers


Place Integrated Circuits

Place ICs in Sockets


Attach Ribbon Cable



Attach Front Panel

Attach Front Panel and Knobs


Final Checks

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?
  • IC orientation: Does the dot/notch on the IC align with the notches on the socket and PCB?
  • Transistor orientation: Does the shape of the transistor match the outline on the PCB?
  • Diode orientation: Do the stripes on the diode match those on the PCB?
  • Resistors: Do all of the resistor positions correspond the chart and/or sorting sheet?
  • Resistor array orientation: Does the dot on the array align with the dot 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?

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

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