Skip to content

Vālvs Build Guide

Jump to bottom
OB1 edited this page Mar 15, 2022 · 1 revision

Building Vālvs is fairly easy and should be pretty self explanatory for experienced builders.

N.B. This guide is using the v1.01 PCB, but the same principles apply to all versions.

Build Photos

Build Step 1 Step 1 - First, solder all of the surface mount parts on the rear of the board. I tend to start with ICs/seminconductors, then solder the passive components afterwards, but any order is fine!

Build Step 2 Step 2 - Next, add the through-hole parts on the rear of the board. The orientation of the trimmers doesn't really matter, but I like to at least have them all the same way round to make calibration less confusing!

Build Step 3 Step 3 - Flip the board over and solder the LEDs so they sit flush with the PCB. Solder the film caps, making sure they will fit under the panel (you can push-fit a pot to check this). If not, they'll have to go on the back. Finally, solder the tubes, being careful to get the right leads in the right holes and making sure none of them touch - I use some heat shrink tube here to be sure it's all isolated. If you do use heat shrink tube, be careful not to overheat the tubes while you shrink it; if you crack a tube, it won’t work!

Build Step 4 Step 4 - Add the panel components (jacks, switches, pots) without soldering, then use the panel to line everything up nicely before soldering.

Build Step 5 Step 5 - In order to keep dust and stray cables out, you can cut a piece of acetate like this and place it between the pots and the panel. I'm sure there are lots of other ways to do this (I've experimented with tape/glue/etc.), but this way is nice and clean and the pots hold it tight to the panel.

Build Step 6 Step 6 - Once everything is in place and soldered, add the acetate sheet and place the panel, then screw everything down nice and tight, taking care not to scratch the panel.

Build Step 7 Step 7 - If you like, you can clean up any flux residue with some IPA for a nice clean finish.

Calibration/Adjustment

There are no hard and fast rules here. The module is intended to be pretty flexible in terms of gain/distortion so it's very much a case of setting it up to your own taste. You could calibrate each of the 4 VCAs as closely as possible to each other to keep things consistent or you could set each up to have a different character/flavour.

Each VCA has 4 trimmers on the back of the PCB:

  • Plate; this adjusts the plate resistance between 8.2k and 28.2k, which affects the overall gain of the VCA
  • CV Init; this adjusts the initial gain voltage, which can be trimmed to ensure the VCA closes completely
  • Clean; adjusts the amount of distortion for the "Clean" mode
  • Dist; adjusts the amount of distortion for the "Dirty" mode

It's fairly important to get the CV Init trimmed correctly to avoid any audible bleed, but other than that, it's down to taste. You shoud be aware that with additional gain/distortion, there will be inevitable additional noise, so experiment to find the sweet spots.

Clone this wiki locally