More missing parts…

So, on top of the PCB mounting brackets and the silkscreened eurorack panels, I go looking through my parts and find out that the BOM is missing two pretty integral parts to any sound module: the output/input jacks and the power headers. What. Went to ERI quickly this morning with Peter to see if they had any headers that would fit, and I almost bought the wrong size. I also couldn’t find any 1/8″ jacks. Luckily, I have some really bad/cheap stereo jacks at home, I just don’t want to use them, this project has been hell-then-bliss-then-hell too many times to put bad or wrong parts in… I can’t even test the circuit right now, so they’re just sitting here.

The problem is that now that the quarter is almost over, I don’t have the money nor the time to order headers that I know will fit from any online retailer. Aside from that, the panels still haven’t arrived, so even if I wanted to wire up the pots and jacks and could power it, it still wouldn’t be finished.

After all this, and couldn’t be bothered to put headers on the BOM? They’re essential, not only for affixing the noise source to the Snare PCB, but powering both modules. It’s the one thing I didn’t check against that screws me this late in the quarter. Who would assume that the Bill of Materials itself didn’t have essential components even listen on it?

Hex is getting an email from me…

In other news, I’m almost done with the Make: book proper, my compressed notes have fit two chapters worth of schematics into 6 pages. I want to dive into the appendices, as they seem more in step with what I want out of this quarter, but it’s taking a bit long to fully digest chapter 6. I’m also skipping completely chapter 7, as I’ve done many-many-many quarters’ worth of notes and instruction on digital audio arranging, and I am very familiar with audacity.

One thing to do for next quarter is to fully examine the reading materials before putting them into a contract.



Moving, Parts!

Moved my workbench today to the new apartment, been getting parts in over the past week, and just checked; all the small parts I bought on eBay are here! (the 20 TL072s too…) Turns out it doesn’t take that long, some were shipped express from Taiwan and Hong Kong. Surprised and impressed. Going to ERI tomorrow to get IC sockets for the Op Amps, the 4006 Shift Registers and the Hex Inverter. Surprised that they weren’t included in the BOM, but I knew that I could pick them up at ERI anytime.

Next is waiting for the PCBs, and I can get started on the NeinOhNeins.

Also, ran out of space in the little book and decided to use the second half of my hybrid notebook as notes for this contract. The Op-Amp chapter is very dense, and I needed to reference the internet several times to understand exactly what was going on in the circuits. I’m proud to say, though, that I’m understanding the bulk of this book, even the tough bits (so far.)

Worried orders

Ordered the last of the parts and components for the NeinOhNein kits, the dates make me a bit worried I won’t be done by the end of the quarter… The PCBs were back “in stock” as of last night and the panels will have to be silk screened-to-order…. Wish I had known that at the beginning of the quarter, I’d have ordered those right away.

I had to buy everything off of eBay, which means the parts will be coming in from all over the world, some say that they might not arrive until November 30th… That leaves barely enough time by week 9 to finish.

The good news is that everything is on order, and, at the very worst, it will get here week 9 or 10, which will give me a week or less to solder components. I’ve double and triple checked the BOM and, if anything I have extras of things I might need later.

Some good to come out of this was that the eBay sellers had a minimum order number, so I’m ending up with a few extra parts (and 11 extra TL072 Op Amps!).

I’ve decided to take a better look at, and the work on this website is filling in the gaps left by the Make: book. I’m finding the “Experiments” Volume extremely useful, even though I don’t have a breadboard to do hands-on; it’s giving me circuit ideas and applications. Good companion, and I wish I had made allaboutcircuits the center of this quarter instead of the Make: book.

I’ve also taken detailed notes up to chapter 4 and started on chapter 5. Chapter 5 is dealing with Op Amp circuits and looks to be interesting, and lots of drawings.

Wish all the parts were here already.


Been reading all the prose I can (up to chapter 4 in the Make book) and decided it was time to do notes. Rereading the first couple chapters, adding notes where new information is relevant to my work this quarter. Might run out of notes space by the end in this little notebook, but I think it’ll be okay if it moves to a bigger one.

Cash finally came in from Evergreen to pay for the components, kits, and tools I already bought and so did the first slew of parts from Mouser for the NeinOhNein synths. Now I have enough cash to order the PCBs and the parts that Mouser didn’t have, along with the panels and the mounting brackets.

Parts I don’t have for the NeinOhNein kits yet:

  • 8x TL072CN JFET Op Amps (They’re not in production anymore, might order a few extras)
  • 2x 2.2nF 5% Metal Film Capacitor
  • 2x .1uf 5% Metal Film Capacitor
  • 1x 470pf 5% Metal Film Capacitor
  • 2x 100pF 5% Metal Film Capacitor

Going on eBay tomorrow if I can’t source the parts tonight.

Adding to the bench list:

  • SOLVENT to get the friggin ugly flux brown stuff off my pretty PCB… Without it I look like a slob.

DS-8 Part 3…

Went to the hardware store downtown and found some nylon spacers and screws that work with the PCB, as well as a drill bit for the larger holes.

I plan on leaving that drill bit in the studio, cause I don’t have a drill (just a Dremel) and I used the space for almost 2 full days now, so giving something back.

Drilling the larger holes was difficult because I didn’t have enough of a grip on the enclosure, and the vises that were there didn’t really do anything, they were both too light to hold up the enclosure and neither of them gripped hard enough to withstand the force of the drill, so I ended up “fudging it” with my hands. It worked out okay, but it just made me realize that using a proper space would have been better for the aesthetics of the thing (holes lined up, etc).

I took the enclosure home and began to wire up the components.


I didn’t really think about how the wires would lay until I was about half done soldering up the wires to the component lugs, then I realized I wanted to be able to flip the PCB over in case I needed to diagnose a problem in the circuit (which I did need to do… more on that later). So I recut and resoldered most of the wires so that they would “tuck” under the PCB. I also grouped the wires together with some heat shrink. I got a bit carried away with that, though, and thinking that heat shrink was more bendy than it actually is, I ended up making the wires thicker and harder to seat properly under the PCB.

It ended up working well enough, but after finally finishing the wiring and installing a battery, the circuit wouldn’t turn on.

The LED wouldn’t go on either, which told me that power wasn’t getting to that part of the circuit. I did some prodding (didn’t take notes, but I looked at the schematic for reference voltages) and found that power wasn’t getting to most of the circuit.


I then traced it to this Diode mod that was included in the instructions (that extra diode) that was supposed to protect the circuit from plugging in a center-positive plug into the jack. Since I will be using a 9V battery, I just desoldered the mod and it worked like a charm.

It sounds so good.

DS-8 Part 2 (ugh)

Got into the Com Building workspace and drilled a good portion of the holes into the enclosure. Found out that I needed a wider drill bit for the 1/4″ jacks as well as the power jack (Don’t think I’ll be using it anyway, but still..)



And here I reveal the layout (giddily putting the knobs on, even though nothing’s soldered in)…





Not much I can do here until I get the new bit, so I went home and used the labeler to label the front panel. I also found out that the PCB standoffs I got from ERI don’t fit the holes in the PCB… I’m puzzled, I thought that stuff was standardized.



I also labeled the pot values and other things on the bottom of the synth, so I can identify where I put things to make the panel wiring easier:



Now to get a drill bit for the larger holes, go back to the shop, drill them out, find spacers that fit, wire up the panel, and see if it works…