Step 1 – Resistors
Follow the BOM and designators “R” on the PCB and put the correct R to its footprint. You see, the resistors are vertical alligned to safe space. The orientation doesn´t matter. Take care, R4, R10, R11 & R12 are in ohm!!!
Step 2 Capacitors
You got ceramic and electrolytic ones. The electrolytics MUST be orientated correct and should be small ones. As you can see you need to bend them if you choose bigger ones. The panel will not fit if the hight exceeds about 10mm. If you don´t have small ones around simply mount them on the other side 😉 But take care of the polarisation!!!
Step 3 – IC Sockets
Sure, you can solder the ICs directly onto the PCB, but i´m not advicing to!
Little trick, attach the sockets with some sticky tape, at first just solder one pin. Make sure it sits tight and plane on the PCB. In case you disrespected the orientation, don´t worry!
That´s why sockets safe your life 😉
Step 4 – Pin Headers
In this step it´s about the pin headers. The power header is mounted on the backside of the mainboard! The 2×9 headers must be mounted in between the PCBs. Which one is female or male doesn´t matter, but make sure you attached them plain and straight. Put the headers together and solder the second pair.
Step 5 – Transistors & Diodes
Step 6 – Thonkiconns
The thonkies have 3 pins. You can´t place them wrong but make sure they sit tight and plane on the PCB, otherwise you will have a hard time attaching the panel. First solder the middle pin, check if it´s placed well, solder the other pins.
Step 7 – SPDT Switch
The orientation of the switch doesn´t matter! Just make it sit tight an plane on its place.
Step 8 – Potentiometers
The pots should snap in and sit tight and plane on the PCB! Solder one pin, check its placement and solder the other legs.
Step 9 – ICs
Place the ICs to their sockets and make sure you respect the orientation. The mark on the PCB corresponds to the mark on the IC.
Step 10 – LED, Panel & Spacer
Place the LED to its place but don´t solder it yet! It needs to be adjusted with the panel. The orientation matters! Long leg round hole. You can choose your desired color but choose a bright one. More mcd means more brightness.
Placing the panel should be easy in case all the parts sit where they should!
In case you don´t have the right tools to mount the nuts use some pliers BUT be careful not to scratch the panel! At first just mount two nuts to make sure the panel is placed well, than solder the LED. Make sure it corresponds to the indicator graphic ….
Both PCBs have mounting holes for a spacer. This makes sure the module stays together even with hardcore road trips. The spacer is 10mm and the screws are typical M3 eurorack.
Step 11 – Quick Check
Check all your solder spots, reheat the critical ones. Check the power pins of the pin header with a multimeter to make sure there is no short!
Issues & Side effects:
Initial output level of 29mV. This is kinda normal with this circuit and never caused any problems for me. In mathematical words a VCA is open for 0,5% which is marginal.
C1 & C2 set the length of the cycle. Bigger size longer cycle and vice versa.