What I Learned From Dusty Tubes and Glowing Dials
Hacking vintage electronics from the 1930s has become more than a hobby for me. It’s a return to fundamentals, a study in elegance, and an ongoing reminder of how much we’ve gained (and what we’ve lost) in modern design. Here’s what I’ve learned.
Hi there, I’m Thierry Durand, founder of Embedded Expertise. Most of my daily work revolves around modern embedded systems: high-speed digital design, FPGA logic, advanced System-on-Modules, firmware. It’s precise, complex, and often abstract.
But sometimes, I put all that aside. I’ll open up a dusty old radio receiver, a tube-based lab instrument, or even a 1930s television set. I start fiddling with vacuum tubes, hand-wound transformers, discrete components, and curious old displays. And I learn. Every time.
These old circuits are more than historical curiosities. They’re lessons in engineering clarity. Here’s what they taught me, and why it still matters today.
Back to basics
Open up a circuit from the 30s, and you quickly realize: there’s no firmware, no SoC, no abstraction layers.
Just pure electronics, built from scratch around Ohm’s law, Kirchhoff’s rules, load lines, and transfer curves. You don’t simulate. You calculate, graph, measure, and tune.
You work with truly discrete parts, and you make decisions with tools like paper abacuses and datasheets full of curves instead of spreadsheets.
And you pick up lessons no textbook ever mentioned. I once spent an afternoon chasing down residual hum in an old radio. The culprit? A non-polarized capacitor… installed the wrong way. Turns out, they’re not truly symmetrical: flipping it actually reduced the hum, and for a good technical reason. You don’t learn that in school.
Another thing always strikes me when I look inside: these devices weren’t built for mass production.
I can’t help imagining the agile hands that soldered each joint, point to point, with no PCB, no test jigs, no automated inspection. Every connection was deliberate. Every bundle of wires bent by hand. And yet many of these devices still work today. A lot of them died too, of course, but history is written by the survivors.
In the early days, many radios weren’t built in factories at all. Local shopkeepers would buy circuit blueprints, order the parts, and hand-assemble radios in the back of the store, tuning each one before selling it.
That’s why you’ll find countless cabinet styles, trims, and finishes, all based on a small set of original circuit designs. It was distributed manufacturing, long before the term existed.
Analog works, and it’s beautiful
We’ve become used to solving every signal problem with an acquisition chain and some sort of processor or DSP. But those old circuits whisper something else: analog still works.
A properly biased triode, a tuned LC stage, a carefully matched impedance, and the job is done. No ADC, no software. Just electrons doing their thing.
And the result? A clean power, a clean signal, and sometimes, a very sexy hum.
Digital displays are not new
Modern engineers might think digital readouts began with seven-segment LEDs. But then you power up a Nixie tube and watch those beautiful orange digits glow to life in neon arcs.
Nixies weren’t just functional; they were elegant. They remind us that technology can be expressive, not just efficient.
…and analog displays are fascinating too
Digital wasn’t the only way to visualize information. In fact, some of the most intuitive displays were analog.
There’s the famous Magic Eye: a green glowing pattern that opened and closed as you tuned into a station. It didn’t show a number; it showed how close you were. Or the shadow meter, where a rotating vane cast a moving shadow on a scale. Or mirror-backed analog needles, precisely engineered to eliminate parallax.
And here’s the key: analog displays don’t just give you a value. They show a trend. A sweeping needle tells you instantly whether you’re rising, falling, oscillating, or drifting. You feel the change without even thinking about it.
These displays largely disappeared in the digital era. But in recent years, they’ve quietly come back on our smartphones! Battery arcs, audio level meters, fitness rings… they’re all digital reinterpretations of a good idea from the past.
Mind your fingers!
Working on vintage electronics teaches humility. A tube plate running at 300 volts doesn’t care that you’re “just testing.” You learn to discharge caps, keep one hand behind your back, and never rush a probe.
Even more sobering are the power supplies. Many early devices used live chassis designs, rectifying AC directly with no galvanic isolation. The DC output was real, but the risk was too.
Touch the wrong point, and you’re the ground path. Connect your scope without thinking, and you’re feeding mains into your instrument.
I once opened an old RCA television, the kind with a round screen and polished mahogany case. Inside was a metal tag, tarnished with age but perfectly legible:
HAZARDOUS X-RAY EMISSION
That moment stayed with me. These machines were powerful, clever… and absolutely not toys.
Modern electronics wraps us in a blanket of safety: isolated power bricks, ESD guards, current limiters. In the 1930s, a mistake could hurt you or kill your scope in a snap.
We are spoiled kids
Come back from a few days with tubes and transformers, and today’s tools feel like magic.
We have simulation environments, reflow ovens, autorouting, overnight shipping, firmware stacks, ready-to-use dev kits, and everything just works. We plug in a board and expect it to power up without even thinking about what’s happening behind the scenes.
But when you’ve rebuilt a 1937 oscillator stage from scratch, it changes your perspective. You don’t take your tools for granted. You look twice at your grounding. You take time to understand what’s going on, not just get it running.
Because deep down, you remember: we are spoiled, and that’s okay, but knowing where we come from makes us better engineers.
I still spend most of my time designing cutting-edge embedded systems. But every now and then, I sit with a an almost century-old radio and a soldering iron, and let it teach me again how electronics really works.
If you ever get the chance, I highly recommend it. You’ll come back to your modern projects with sharper instincts, a deeper respect for your tools — and a little smile every time you hear that discreet hum.
Want to see what I do when I’m not chasing grid bias? Visit us at https://emb-exp.com to learn more about our work in embedded systems design, or click the Contact button below.
