If you’re into audio electronics, you probably know how quickly one project turns into five. A small amplifier leads to filters, then measurement tools, and before you know it, you’re building your own test setup. That’s exactly the feeling I got while browsing through Elektor’s Audio Collection.

Spanning 30 years of Elektor Magazine, this USB stick brings together more than 475 audio circuits published between 1995 and 2025. What stands out immediately is the variety. It’s a mix of classic designs, modern embedded projects, and a few unexpected ideas that make you stop and look twice.
To make things easier to explore, I grouped a few highlights that really show what this collection is about.

From Classic Circuits to Solid Building Blocks

Some projects feel like the backbone of audio electronics. The Compact 12 W Hi-Fi Mono Amplifier is one of those. Clean, focused, and very much in line with what you expect from Elektor. The same goes for the Fliege notch filter, which is less flashy but incredibly useful if you are working on measurements or cleaning up signals.
Then there is the 12-to-200-V DC/DC Converter for Valve Amplifiers. It is a bit more niche, but that is exactly why it is interesting. It shows how deep the collection goes, especially for people who still enjoy working with tube audio.
Audio amplifier schematic diagram from the Compact 12-W Hi-Fi Mono Amplifier

Digital Audio and Embedded Ideas

Moving into more recent territory, the Raspberry Pi Pico spectrum analyzer really stands out. It is a great example of how audio projects have evolved. Instead of just building circuits, you are now analyzing signals, visualizing them, and combining hardware with software.
The I2S test signal generator fits nicely in this category too. It is more technical, but it shows the shift toward digital audio design. And the USB to S PDIF interface is one of those practical builds that solves a real problem when connecting modern devices to older audio gear.

 

Raspberry Pi Pico as Spectrum Analyzer

Radio, Music, and Interaction

The FM radio with RDS is a great example. It might sound familiar at first, but this project goes much further, combining a custom Raspberry Pi HAT, dedicated receiver hardware, and a touchscreen interface into a complete radio system with its own software.

The MIDI I/O breakout board is a straightforward, standards-compliant interface that enables reliable connection between MIDI devices. While simple in concept, it supports a wide range of applications, from synthesizers and controllers to more elaborate music technology setups.

 

FM Radio with RDS

Small Ideas That Make a Big Difference

One project that really caught my attention was the digital bubble level with a stroboscopic disc for turntables. It is not something you see every day, but it makes perfect sense once you think about it. It is practical, a bit quirky, and very much rooted in real-world use.

The simple 7-band audio spectrometer also fits here. It is visual, easy to understand, and just fun to build and use.

Digital Bubble Level and Active Stroboscopic Disc for Turntables

Final Thoughts

What I like about Elektor’s Audio Collection is not just the number of projects, but the variety behind them. You move from classic amplifier designs to things like spectrum analysis or digital audio interfaces, which keeps it from feeling repetitive.

It also shows how audio electronics have evolved over time. You still get the analog foundations, but they are now combined with microcontrollers, software, and integrated designs.

If you are looking for inspiration or just want to revisit some solid designs, this collection is definitely worth exploring. Chances are you will not stop at just one project.

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