Demystifying Electronics: Power Supplies, Embedded in Audio, and More

How are cutting-edge electronics — from powerful power supplies to sophisticated embedded systems in audio amplifiers — designed and engineered? Veteran engineer Eddie Aho reveals the practicalities of PCB design, the surprising realities of high-fidelity audio, and much more.

Aho is the talented engineer behind the popular Kiss Analog YouTube channel. In a recent discussion with Elektor editor Brian Tristam Williams, Aho touched on the practicalities of power supply and audio amplifier design, the evolution of PCB creation, and the surprising realities of high-fidelity audio. He offered insights into his background, his interest in electronics, the evolution of technology, and the importance of practical, measurement-based approaches to understanding complex systems.
 

From Aerospace to Educational Content: The Genesis of Kiss Analog

With decades of experience in aerospace, defense, and consumer electronics, Aho shared details about his journey into YouTube content creation. What began as an exploration of the latest oscilloscope technology for potential contract work evolved into a passion project driven by a desire to mentor and share his extensive knowledge. His channel, "Kiss Analog," aims to make serious electronics accessible online, tackling real-world amplifier testing, reverse engineering circuit boards, and debunking common audio engineering myths with factual measurements.

“I'm actually still working in defense,” Aho noted. “But I thought I was going to start doing some contract work on the side, set up a bench, and start doing what everybody else does: looked at YouTube to see what the latest was on oscilloscopes. And then, I just kind of started thinking: ‘Hey, why don't I do a channel and show my projects?’ And so that's kind of how it started. And I've always liked mentoring and, you know, helping others. And so it just seemed like a good fit.”

Audio Amplifiers and the Perception of Sound

A significant portion of the discussion revolved around audio amplifiers, covering the distinctions between Class A, Class AB, and Class D designs. Aho elaborated on the characteristics of each, particularly the digital switching nature of Class D amplifiers. The conversation also delved into the intricacies of human hearing. This led to an intriguing discussion about the purpose of amplifiers with bandwidths extending far beyond the audible range. While humans may not hear these higher frequencies, the electronic components, especially speakers, are still exposed to them. Uncontrolled high-frequency signals can negatively impact tweeter and speaker longevity and performance. This highlighted the importance of analyzing the full frequency spectrum, not just the human audible range, for proper electronic design.

The Evolution of PCB Design and the Importance of Schematics

The discussion touched upon the significant advancements in PCB fabrication. Many Elektor community members are familiar with the challenges of etching circuit boards at home with chemicals, a process that is not only cumbersome but also environmentally questionable. Both agreed on the immense benefits of modern online PCB services, which offer affordable and quick turnaround times for custom boards. Aho, currently considering KiCad, a free and powerful PCB design software, emphasized the critical role of schematics in successful board design.

"I want to show people how like an engineer approaches a PCB design versus like some of the other stuff I've seen on YouTube," Aho explained. "I saw a guy one time design a board without a schematic. And I'm like, wait. And then, of course, it didn't work." 

Affordable Test Equipment and Sampling Theory

The conversation also celebrated the increased affordability and accessibility of modern test equipment, particularly oscilloscopes. Eddie expressed his satisfaction with the recent emergence of 12-bit oscilloscopes at reasonable price points, a significant improvement over the long-standing 8-bit standard. While acknowledging that some high-end equipment may originate from China, he pointed out that many American companies also manufacture their products there, making it a widespread reality in the industry. The discussion touched upon the Nyquist-Shannon sampling theorem, with Aho touching on accurate waveform reconstruction, digital sampling rates, and more.
   

Future Projects

Looking ahead, Aho revealed his renewed focus on power supply design, which was originally intended to be a core subject for his channel. Despite initial lower viewership for these topics compared to multimeter reviews, he plans to dedicate more content to complex power supply designs, including active power factor correction and more. He also plans to make PCB designs available for his audience. 

This engaging discussion offered a refreshing dose of reality, demystifying common audio myths and highlighting the core engineering principles behind power supplies, audio amplifiers, and modern PCB design. Aho's insights remind us that true understanding comes from practical application and measurement, fostering a more informed approach to electronics for both hobbyists and seasoned professionals.