Yeah, it may technically be a reverse avalanche…but I had a hard enough time just fitting “avalanche” on there
Made half of another module last night. Still waiting on some components for things I really need to get a rack together (LFO, VCA, Envelope generator…) but I have the neutron I can patch through for most of that and the Tiny Dazzler “Percussive Noise Voice” was just too simple of a circuit for me to not try whipping one or two up.
Wound up only whipping one up even though I made the panel for two because I made a few mistakes on the stripboard. BTW - these are my first attempts at using strip board. I’ve done TONS of PCB’s, a couple of free form circuits, tons and tons of breadboard circuits, and a number of circuits on plain vector board with no traces…but these are my first attempts with strip board and I’m still getting my head around it.
Want to play spot the mistakes on this one?
Getting it going was a bit of an adventure. First I got backwards right from the start and put the power connector on the wrong side of the board. Then I started making my trace cuts before I noticed. Oops. Then I managed to get the transistors backwards (trying to figure out the components on the non-trace side vs. how they appear in a strip board schematic.) But I was still just getting a click out of it not noise. Traced everything through and couldn’t figure it out. I did note that the original schematic (which took a bit of digging to find since Tiny Dazzler’s original site lost most of it’s images) had one resistor listed as 47k but the stripboard layout by @Doolang in this post which I was going by had changed it to 4.7k. But it seemed like his layout worked…so…pretty sure that wasn’t the problem.
Then just before I quit for the night I saw it. I missed one jumper. Rather important one too since it’s the one that bring +12v into the circuit. Doh! Quickly soldered that on (just on the trace side, was too tired to route it cleanly on the component site) and it works, just triggering it from the LFO on my neutron for now, but it works!
I also redrew the layout in DIYLC as a chance to start learning DIYLC and so I could make a few minor adjustments to add in the shrouded power header I like and shift the jack/pot wiring a bit to make it easier to use pin headers to connect them.
Note - I don’t show the values for the “HIT1/2” caps that determine the voice. And for reference since it was such a pain to find here’s the original schematic (which I found from one of Kristian Blåsol’s MIAW videos:
Note - I kept the C2/C4 caps from @Doolang’s layout…but am about 99% sure there’s no point in them since the -12v rail isn’t used on this circuit. So when I build the snare side I’ll be leaving those off. (and the -12v jumper wire - but keeping the trace cut to isolate the -12v line of course)
I’m also tempted to tweak the panel to make room for the LED…I didn’t even notice it in the circuit when I designed the panel. But…the panel is a bit tight already so not sure if I’ll get that ambitious
The look of the white with black module panels is starting to grow on me. May have to make a few more of these and see how they look…and definitely need to make time to put together a rack this weekend:
Speaking of my tweaks to the layout to accommodate pin headers. This is something I learned to stop being cheap about a few years ago. 15 years ago connectors were a lot harder to find cheap. I still have some name brand molex headers/pins I bought for my orignial midibox projects and remember treating them like gold because of how much they cost compared to passives and even most of the semiconductors I was used to using. I couldn’t buy them anywhere local, and they weren’t available from places like ebay, amazon, aliexpress yet. So I hardwired a lot of things that I now wish I had put connectors on. Oh, I included pin headers (those were at least cheap) but I just soldered right to them (which I now regret since cleaning them up to put connectors on them is a pain!)
With “dupont” connectors so cheap now and pin headers even cheaper…I use them much more liberally and it’s made life so much easier. Yes…it is one more potential thing to fail in a project that gets knocked around a lot. If I was building a synth to take touring on the road like Sam I would probably just solder direct to the board. But for a synth that’s going to stay in my house and have it’s guts tweaked with a lot…the flexibility and ease of assembly afforded by connectors is well worth the minor extra expense and risk of an additional point of failure. Building the second half of this circuit with jacks and pots danging off this side wouldn’t be fun at all. And desoldering/resoldering them while not that big of a deal does risk damaging traces so I’d rather avoid it.
Biggest problem I have with using more connectors…I seem to constantly be out of 2 pin housings! And while I can buy a big bag of 100 off aliexpress for about $1…that’s with slow boat shipping that will take 2 months to get here and I don’t usually plan ahead that far And quicker shipping is just way too expensive. Oh well, I’ll just use some single pin housings and super glue while I wait