In my last build I mentioned that I needed a proper mixer to explore the sounds that I could get from the fuzz distortion module so I set to build one. Initially I thought I’d build a stripped down version of Ken Stone’s matrix mixer, but I quickly decided that it was an overkill for what I needed. So I built a classic “multiple inputs into two inverting op amps” kind. There must be quite a few variations of this topology, but I used a simplified version of @ShedSynth 's mixer, that doesn’t use any switches or clipping indicator.
Now I am pretty sure that someone must have posted a stripboard layout for this in the forum, but I had this 12x9 stripboard offcut so I gave myself a challenge to fit as much as possible in there, including one of the potentiometers. I also didn’t have any 100ohm resistors, and the closest I found was a chunky 1w resistor. I figured that it’s only used to prevent short circuits at the op amp output, so I just soldered it directly to the output. Good enough for rock 'n roll I guess
What is concerning is the FM potentiometer. I have NOOOOO clue why it’s there as it’s not in the schematic and … gotta look at the docs again … YAY!!! I’ve got a spare potentiometer and a hole to cover.
Maybe I fix the cabinet tomorrow so I can start planning for the layout of all modules and start adjusting and trimming them.
The CGS modules are rather cool as they don’t really look like “normal” modules and maybe they serve me pretty good as I do hope I can make something that makes sort of regenerative music.
Can’t see a pot in the schematics for FM depth, but the wiring shows it as an input level control, nothing seems to match up to the schematics, the switch etc.
That’s a problem with some of CGS’ designs, the documentation isn’t always . Guess many are pretty old, some are updated and details are simply there for the builder to fix. I’ve got the Infinite Melody and the Weighted Random Switch and struggle a bit with the panels as it isn’t 100% clear how to connect the boards to the panels.
I must say, though, that it is fantastic that Elby-Design and Laurie Biddulph are offering these modules (pcbs and panels) just because they are a bit odd.
Well, that’s the stupidest mistake to date. I put microcontroller on the wrong side of the pcb, so I had to cut a hole on the front panel to make it fit. At least I can try to tell people that it’s on purpose for debugging reasons…
Would there be enough room to push or pull the pins of the Daisy to the other side of its PCB and then mount it to the other side of the module’s PCB? Then a hole in the face plate might not be necessary.
Technically yes, or I could solder the Daisy straight to pcb, but that would be wasteful if I want to use it in somewhere else. I just waste one front plate, as I have 5 of them due that being the minimum amount from JLCPcb, and design new main pcb and order that for the next version. There’s always something on the pcb anyway I want to change after first prototype.
I asked a mate of mine to 3D Print me a blank panel for my Kosmo rack. Turned out pretty good. It is 200 x 50 x 4mm. It turns out that 4mm is a tad thick. Next time I will ask him to print 3mm for me. Yes this is a DIY Mult.
Finally finished soldering on my Moritz Klein VCO. I laid it out for this circuit board based on the schematic from the Erica Synths EDU manual. It’s late AF so I’m going to test it tomorrow, but WHEW it’s taken me a while to get this one finished!
It looks pretty cool ! Not sure it will be something anyone would play for very long on it, but it is certainly designed for “happy” accident (or so it seems).
Had to steal the envgen8cs from the VCA but at least the 3350 filters are working.
I’ve only ran it through my test speaker but it sounds nice.
Need to tweak the values a little, frequency cut off doesn’t quite open enough.
And I’d heard the resonance could be weird with these chips - with it maxed out I do get odd clips and weird popping/dead bits when sweeping the cutoff. Strange behaviour… wonder if there’s a fix beyond just adding a resistor to the pot to reduce its max.
Just for fun, here’s a picture of my Turing Machine family. At the left is a completed Turing Machine with two Volts and a Pulses on the same panel and a separate Vactrol Mix (using home-made vactrols). The right is a work-in-progress Turing Machine also with 2 Volts and a Pulses, plus the modified TM_LPG-X module. I hope to get them finished this week, and then I really must get on and make another case…
