So my subject line is going to become increasingly inaccurate but I don’t want to clutter things up with a new thread for each module. This is really more of a build log than just my first synth.
Last night I decided a LFO would be nice to have next since I have to keep going to my neutron for one testing things. Debated a few simple LFO options I could build and decided to try the “Simple LFO 1.4” from David Halliant seemed like a good design and MIAW’s build indeed looked simple. But I don’t like working straight from a schematic to solder…so started drawing up a stripboard version first. And…quickly decided that my stripboard routing abilities were not quite there yet!.
So Instead thought it would be better to find an LFO with an existing stripboard layout. And what was in the first post in the verified stripboard layouts thread? A "Roland System 100 LFO’ a dual no less…and verified as working by @Doolang who’s noise drum layout work well for me on my last module. Sure!
For practice I decided to redraw it first. Considered converting it to use a single TL074 instead of two TL072’s but I have a bunch of TL072’s on hand…and also decided a dual wouldn’t quite fit in a 20mm wide module. Especially if I added the shape pot a variant posted later added. I also found the labeling somewhat confusing and in my late night stupor wasn’t able to figure out just how it was meant to be wired to pots/jacks/switches…But found this layout of the same circuit as a single which was labled a bit more clearly:
Or at least…was a bit more clear to my late night brain. But as I started to redraw it…I quickly decided it made way less efficient use of stripboard than I wanted for a quick and dirty LFO. So…I took a bit of inspiration from both and redrew it to fit on a scrap of stripboard left over from my last two modules:
Yeah…my jumpers are a bit uglier…but it fit in the thin strip of board I had. I also added some caps on the power rails since I was surprised to see there weren’t any.
Soldered it up then drew up a panel and set it printing while I worked on a little home improvement project. I’m starting to get my process for drawing panels in Fusion360 down pretty smooth. If there’s interest (and it sounds like there may be) I may try recording the process next time.
I didn’t bother with adding pin headers this time…I wish I had since the wiring is a mess now…but…I just didn’t see a good way to make them fit on the small scrap of board I was working with.
Hooked it up to my oscilloscope first…and…it works…but it’s not exactly a LOW frequency oscillator. The lowest frequency I was getting out of it was about 40hz. And using the range switch it sometimes freaks out and stops oscillating all together. I tried removing the electrolytic caps I put on the power rails just in case somehow that could be causing a problem (though I couldn’t think of why it would) but sure enough it’s still acting the same.
Oh - I also messed up and forgot to include the Waveform switch on my panel ( I decided to go with a switch rather than two jacks…but may change it to two jacks) and wired what I had labled as range to the waveforms. So had to make some sharpie and drill mods to the panel.
Here’s a little video of where it’s at.
In the video you’ll also notice that the snare side of my noise drum has developed a fault as well…both the snare and hi-hat were working…but now suddenly the delay knob on the snare isn’t working. Not sure why yet. Tried swapping the pots and it acts the same so it’s not a bad pot or wiring on the pot is all I’ve determined so far. Will have to take a closer look tonight.
Not sure if I mangled something in my re-draw…or in my assembly…or what yet. Will have to take a closer look a little later this evening.
Right now I’m about to get shade over my work area outside. (it’s apparently 118f out right now and lacking a shop all my woodworking gets done outside) So going to take my kid out for frozen yogurt then hope it cools down a bit and I get more shade so I can cut a few boards and toss together a case.
Oh - I also tossed together a little power buss so I could hook up more than one module finally…and made some more power cables with the red stripe on the correct side:
This should tide me over for a few days…I ordered one of @analogoutput’s boards off his Tindie this morning to go in the case 
And speaking of Analogoutput’s projects…I did get another package yesterday that wasn’t empty:
I knew I wanted a quantizer…and liked the idea of the DAC/INO board for experimenting so when I saw his post I more or less immediately ordered a few boards from JLCPCB. I only need one faceplate since I only plan on building on quantizer…so will make the other 4 available soon. JLC shipped so quick I didn’t even have time to order a few parts I don’t have on hand for these though so it will be a bit before I get it built up and put the extras up. The DAC boards…I kind of want to keep one or two more for experiments though so I I’ll have more faceplates to get rid of than I will full sets.
But overall I’m starting to like the way my 3D printed simple modules are looking - can’t wait to get a case built this evening and try mounting them up…hopefully that will also help stop things like the snare suddenly deciding to stop working right 
If anyone has any thoughts on what I should look for on the LFO or Snare when I get to debugging them this evening I’d love to hear it!