Build Shit - DIY - What's On Your Bench?

[¾ dead]

Another DIY tool I cobbled together: this is a test bay for body contacts. More specifically, it’s just a piece of cardboard bent into a box-like shape with thumb tacks stuck into it; the business ends of the tacks are then soldered to wires that lead to points of interest on the PCB. This makes testing potential body contacts a lot more intuitive & closer in ‘feel’ to how the final product might be interacted with.

kewl.
This reminds me that I keep forgetting I want to build a jack-to-contact converter eurorack panel to make exploiting touch-reactive inputs less sloppy/more performative than groping at disconnected patch leads.

[FAP]

Progress shots from the build discussed in this topic:

Will definitely be tired of rotary phones after this... and this is only the first one so far!

[crochambeau]

Still sorting out my negative rail, but otherwise my latest utility circuit seems to be behaving.

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[FAP]

Needed a ground source for my bench so I whipped this up:

Note the "hot" and "neutral" connectors aren't wired to anything and are in fact further isolated on the inside of the plug via rubber caps: the only thing running through the cable is pure ground, which then branches off into an optional ground+1MΩ for the sake of ESD prevention.

[crochambeau]

I was going to edit my post to indicate that the root of my problem (a 34063 based switch mode voltage inverter) was my having selected a 6.66 ohm resistor when a 0.666 ohm resistor was required to meet my current needs (100 mA range). But apparently I am not empowered to edit my own posts.

Fuck whatever scumbag initiated that setting.

That's a super cool ground source FAP. Please be aware that if you're veering into working on things attached to mains power that an isolation transformer (essentially severing ground reference for device under test) is another level of safety that can save your ass.

[NoiseWiki]

I was going to edit my post to indicate that the root of my problem (a 34063 based switch mode voltage inverter) was my having selected a 6.66 ohm resistor when a 0.666 ohm resistor was required to meet my current needs (100 mA range). But apparently I am not empowered to edit my own posts.

Fuck whatever scumbag initiated that setting.

The edit function has a timeout..

[FAP]

Finished my Blue Box clone build today: I'm pretty happy with it

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Only thing that sucks is the sticker overlay is messier than I would've expected it to be; you can see some fingerprints on the side, but even without those it looks kind of dirty up close. I didn't space the text for the knobs either, though I didn't expect to have knobs that size when I sent in the final draft for the sticker.

Speaking of knobs, here's a little trick I used to uniformly space the knobs away from the enclosure:

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Yep, just place two of those white washers that come with 3PDT foots witches on either side of the pot and you've got the perfect gap to allow for a smooth rotation. Try it out!

[FAP]

I just spent the last 1.5 months transforming this:

Into this:

And now I'm here to talk about it.

First, the mods:
+ master volume knob (built-in EHX LPB-1 booster circuit)
+ delay feedback knob
+ delay time knob (approx. 50-500ms)
+ LFO rate, shape and depth knobs
+ output tone switch (high/low)
+ noise switch: turn on to introduce an infinitely oscillating noise texture into the signal, which can be further manipulated via the other controls
+ decay tone switch (bright/natural)
+ LFO and true bypass foot switches, each with LED washers (the white discs) in lieu of traditional status LEDs
+ momentary input mute button
+ effect output
+ additional direct output
+ effect input with standard TRS switched power setup (i.e. have the option to power via a battery, though as you can see by the gut shot that's not an ideal option)
+ momentary reset for debugging purposes

Honestly, I wouldn't recommend doing this build.
I'm quite proud of the design work I put into it, don't get me wrong; the reason I was able to exploit this crappy little karaoke microphone as much as I could is because it utilizes the PT2399, a well-documented digital delay chip that's been used in better and much cleaner-sounding builds over the years.
The rest of the mic's circuitry is decidedly less clean, however.
Case-in-point: I had to add a booster circuit on the output signal to make the thing reasonably audible.
Worse still, this is one of those circuits that needs preamp on the input signal: obviously that's not included in the final build, so I had to whip-up another booster circuit to compensate:

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Also, the reset button is in an awkward position wherein a patch cable could potentially trigger it by accident; the reset doesn't need to be in the build at all since the stock circuit is fairly stable, so maybe one day I'll swap it out with an input level pot or something...

Point is, while I'm glad it turned out as well as it did, you can do much better things with the PT2399 alone than you can with it attached to an el-cheapo microphone meant for kids.

[FAP]

Shockingly (if you'll forgive the pun) my next and last build of the year has nothing to do with rotary phones:

This is my own take on the Sonic Reducer, which itself is a cleaner and much-improved take on the Analog Bit Crusher.
The effect is just that: a bitcrusher (or more accurately, a close emulation of one) made from analog components.

In addition to the standard sample rate ("RATE") & resolution ("RES") controls, I added a few more doodads of my own:

• voltage sag (power starve) knob w/ toggle
• extra bass toggle
• volume knob
• true bypass w/ switched battery power input
• blue led [to contrast the orange]

Thoughts/notes:

1. If you want to build one yourself, I recommend using the perf I made (see below) instead of the one linked above: I couldn't make heads or tails of it myself so I re-drew it from scratch. It could definitely still be improved upon & compacted further; I drew it in a way that would fit my enclosure as well as leave at least one spare hole for most traces in case something went wrong during soldering.
2. Wire management remains a struggle. I try to make the wires all long enough that the whole thing can be split into two halves, with each laying comfortably on the same flat surface: this may be good for repairs later on down the line, but having to squish those longer lengths of wire into the ultimate enclosure is its own challenge. Furthermore, the wires lead from all sorts of places on the perf; the only way I can see to improve this would be to have a separate place on the perf (or even a separate perf altogether) for the sole purpose of routing those disparate leads to a singular, more uniform "bus," theoretically minimizing perpendicular wire crossings/entanglements.
3. The enclosure was repurposed from the base of an old lamp; the orange part in the center holding the LED was repurposed from a rubber stopping cap that came with one those solder flux syringes, which just so happened to fit perfectly.
4. Taking note from Crochambeau's thoughts on the topic, this may be the first build where I actually used the anti-rotation tabs on the pots for their intended purpose. Thanks, Curtis!
5. I originally wanted to stamp-in the labels with metal lettering but that didn't work, so I took the plunge into label-maker land. I'll be blunt: the Dymo I bought (new!) was a piece of shit. It's a miracle I was able to get all the labels I needed for this build, because every fourth or fifth pull of the trigger the damn thing would jam or fail to press a letter. I took it apart, cleared the label guide and re-aligned the wheels but it still shit the bed. I've since introduced it to the pavement and will be on the look out for sturdier alternatives.
6. That PF sticker is covering up a rather large gash left by prying-off a piece of mounting hardware in the original enclosure. This is also why the user-facing side of the bottom looks kind of fucked-up: be careful with tools, kids!

Schematic and perf layouts below:

[FAP]

Say Curtis, off the back of that wiring dilemma I mentioned in the previous post, what wires did you use for this build? They look like a really good balance of size and flexibility while still being sturdy enough to not flail like wet noodles.