Prototyping two tone, a 2X passive lowpass gate and filter with DIY vactrols

Tech
#1

I wanted to work on building a simple module from start to finish to test out some panel fab ideas and I thought a LPG/LPF would be a good candidate. After listening to Why We Bleep Ep.2 with Abstract Data and talking about the character of imperfection in analog circuits, I thought making a DIY vactrol based board would be interesting! I also thought if there were 2 halves, you could use slightly different components and vary each to make them truly distinct from one another. You can get different characteristics in the filter depending on the size and material of the LPF capacitor.

Panel font by Alice Savoie / CNAP CC BY-ND 4.0

Presenting two tone, 2X passive LPG/LPF in 3hp.

PCBs:


Final Assembly:

In my rack:


the snappy bass is the main two tone thing at work with a short gate LPFing & LPGing a Noise Reap Bermuda’s Sine output. the second is coming from the chord organ, but it’s much more subtle. :headphones: or nice :speaker: for best results.

Github repo coming soon with rev2 board (I need to flip the LPF attenuation direction)

31 Likes
#2

Gorgeous panel! Looking forward to hearing some sounds.

#3

Awesome, can’t wait to hear it!

#4

I will buy please thank u

#5

Looks great Ben!
I love the “vactrols”!! :joy::clap::muscle:
Can’t wait to try this!

#6

good panel in twenty characters!

2 Likes
#7

Looks absolutely beautiful! Very interested in one of these when they’re available : - )

#8

Here are some sounds! – the snappy bass is the main two tone thing at work with a short gate LPFing & LPGing a Noise Reap Bermuda’s Sine output. the second is coming from the chord organ, but it’s much more subtle. :headphones: or nice :speaker: for best results.

1 Like
#9

Very nice! Any ideas on how the sound compares with a DPPG?

#10

I don’t have one, so I cant really say, although @laborcamp is going to test one out for me against a few other lpgs he has soon. I imagine it’s pretty similar though. One difference is that the DIY vactrols are likely going to have much more play in the LPG overall and each of the 2x could be made to operate completely different from one another using different resistance range LDRs. Also, the DPPG does not have an attenuable LPF built in, so that’s an addition here.

1 Like
#11

Always room for one more module…

1 Like
#12

Files are now on github!

4 Likes
The Travelling Rack Project
#13

Nice! Just what I was looking for. I ordered a few PCBs/panels and will build two!

@bmoren. How did you create the panel? Is there an illustrator to kicad converter?

1 Like
#14

There is not a direct converter, but there is a bitmap importer into Kicad. So, if you keep the resolution up and work at 100% scale, you can move things around. It’s pretty clunky, but it works. There is a way to work with DXFs, but I’ve found that it’s really only useful for working with board outlines.