NE555 Projects on 5/5

After 160 circuits built I decided I really needed to start adding more utilitarian builds to my roster. Thanks to tagboard effects I found a voltage inverter and voltage doubler that use the exact same layout, but orient the parts slightly differently to achieve different goals. I've avoided building some pedal circuits because they need a negative nine volts, and I've avoided building others as they require an internal charge pump to double the voltage. I figure, why not build these little circuits and have external options for powering pedal circuits? Especially when it saves me having to buy a charge pump specific IC every single time I needed to achieve either of these voltage requirements.

Both of these circuits require the use of the old tried and true 555 timer chip. These projects sat in my box of 2026 kits for a few months, until I realized it would be neat to build them on May 5th. This wasn't purely my own idea, I have to admit. BigClive inspired me with his video posted today. That, couple with the fact that I had so much fun yesterday using my old RadioShack soldering iron, I figured why not!? Again, both layouts are identical in terms of board size, trace cuts, jumpers and most of the parts. The varying voltage output is all down to how the diodes and electrolytic caps are oriented within the circuit.

There isn't much more to say, if you've checked the layouts at tagboard's website you pretty much see everything you need to. Super simple, super low component count, and (hopefully as I've not tested them out yet) super useful. Now I can build circuits that require negative voltage and eighteen volts without having to worry about powering them properly. I mean, I could build these for each pedal that requires them, and in some cases I may. The main idea though is to have a power box with these options, so I don't need to mess with all that in the future. There are a few other 555 timer related circuits I plan to build, but those will come later. These were just super easy builds I felt deserved to be "born" on May 5th.

Using Archaic Technology!

Since my nephew turned one this year I wanted to build him a simple boost circuit for his birthday. As I've done in the past, for a few friends, I build the circuit on the actual day of their birth so they and the circuit share the same birthday. Typically it's just a simple LPB-1 or a treble boost, nothing too complicated as I'm simply building these mostly for non-musician friends as keepsakes. For little Erik I decided to build him a LPB-1. Maybe someday he'll want me to custom build him something a bit more complex. Heck, maybe by then I'll be building guitar amps too. Who knows!

The LPB-1 being as simple as it is, I didn't want to break out my soldering station and make a big mess, as today was a rainy day, making getting outside a fool's errand. Instead I dug through a little toolbox under my bed and pulled out an old RadioShack 15 watt soldering iron I had barely used before. I found it at the outlet years ago and figured it may come in handy someday. Little did either of us know it would be about ten years before it came in handy, but come in handy it did!

This thing takes forever to warm up, but once it's ready it put plenty of heat into the board and the component to make pretty decent joints. I can't say they're perfect, and sometimes the solder creeped through the hole and onto the actual component being soldered to the board below, but all in all this was a fairly good experience. The tip is conical, which I'm not really familiar with as I prefer a more angled, chisel type, like on my soldering station. Even so, I still have to say this little blast from the past did a decent job.

The joints are a little blobby, but they seem solid. I have to say building the circuit for my nephew, and using the old RadioShack soldering iron made this one of the more enjoyable builds I've done in a while. I probably wouldn't want to use it for anything wildly complex, or high component count, but at least now I know for smaller builds, or maybe even troubleshooting, modifying, or repairs this soldering iron is wholly capable. Now if I could find the chisel tip I like somewhere I think this soldering iron would get a lot more use than it currently is.

Univox Uni‑Comp Vero Nightmare Solved!

It's been sitting in my needs troubleshooting box for over two years, and finally I decided to stare the dragon straight in its eyes and figure out what exactly was going on, or in this case not going on. Many years ago I had built a Really Cheap Compressor and I liked how cheap and effective it was, so when I saw the Univox Uni-comp I decided this would be a piece of cake! Little did I know, initially, it was more like a pile of crap. After this little circuit failed to work at all I went to the search engines and found that, what looks like a very simple circuit on paper, seems to be notorious for not being able to get it right. There are multiple schematics and layouts that all differ, with very poor success rates from what I'm reading as well. I'm not a very smart man, but I am tenacious!

The original layout I used

With legends being passed down from generation to generation that this circuit is indeed viable, I decided to sit down and compare all the schematics and layouts I could find. I made 100% sure that mine was exactly like the layout I used (above), and it was. From there I started tracing things back and forth between all of the layouts and schematics, and I noticed a few things. On the layout I used, the 3.3M is going through a jumper to pin 3, as where all the others went to pin 2. I desoldered the jumper at pin 3, stuffed it through the cut trace beside pin 2, and soldered it where I attached the socket beneath. Then I traced both 1M resistors at pin 3 and realized neither went to ground. The lower of the two went precisely where it was meant to go, so the upper required me to move the top leg down one space, which now gave me the correct voltages on the LM741. I also noticed the LED anode and it's components weren't isolated, so I made a cut to do that.

Once those changes were done, I finally had audio, but just barely. The LED was also behaving like it was possessed. Sometimes stuck on, sometimes refusing to light at all, making me think I’d cooked it. Between the weak output and the LED acting like a mood ring, I was stumped. I checked every schematic and layout again, and everything looked right. That’s when I turned to AI (big ups to Copilot!). I showed it the layout, explained the fixes I’d already made, and after some thinking it told me the LDR needed to connect to Q1’s collector. I scoffed. In none of the schematics or layouts does the LDR go to the collector of Q1. In mocking robot voice: “Error, error, cannot compute.” But the AI was persistent. It suggested disconnecting the LED and LDR entirely to see if the volume came back. Wouldn’t you know it, it did! Not only that, but with the Comp and Level maxed, the thing actually turned into a surprisingly cool little overdrive. That’s a project for another day, but it proved the sidechain was the culprit.

I questioned my use of an MPSA05 instead of an 06, and AI assured me the only thing that needs to happen is the LDR needed to connect to Q1's collector. Fine, we'll try it your way. *eye roll* Well, yet again I was wrong. Now I'm not saying it's perfect, but it actually works. The LED flickers into the LDR, it compresses, but it is gritty. Could this be the 1N4148s? Who knows. The reality is this little circuit now works, again probably not perfectly. What I had written off over two years ago now actually works. So if you're one of the people who had issues with the Univox Uni-comp, here are the changes to make to the layout above to get you started.

• Add a cut at E12 to isolate the LED and it's components
• Move the Jumper from I6 to H6, connecting to Pin 2
• Move the 1M top leg from D4 to E4, giving the opamp proper voltages
• Connect the top leg of the LDR to C11, connecting to Q1's collector

I will reiterate that this is probably not as close to the Univox Uni-comp as it could be, but it's a good starting point, and it makes the layout above viable. I can officially change my notes on this build from "Doesn't work!" to "Gritty, but works!". Hopefully this helps some of you out there. If it does, please let me know.