Those with a love of knowledge may enjoy these articles from Hephaestus Audio.


Switching Amplifiers

How to Design a Class-D Amplifier — What are the basic requirements and considerations for designing your own class-D amplifier?

Solid Execution — Class-D, class-T, and class-XYZ – what really makes for a well-designed switching audio amplifier?

Class-D Efficiency — How does the efficiency of a typical class-D amplifier compare with the efficiency of a typical linear amplifier with real world use?

Supply Pumping — “Supply pumping” is a phenomenon that results from the natural recycling of energy in a single-ended class-D amplifier.

Hysteresis Modulator — An example of a typical class-D modulation scheme:  self-oscillating hysteresis modulator.

Phase Shift Modulator — An example of a typical class-D modulation scheme:  self-oscillating phase shift modulator.

MOSFET Body Diode — The body diode of a MOSFET is usually slow, but why is this important?  Also, what can be done to deal with it? 

Magnetic Losses — Once you have a rough design for the magnetics it is critical to estimate what the losses will be.


General Audio

Grounding and Layout for Audio — “Star Ground” versus a “Ground Plane” plus some tidbits on layout.

Engineering Perspective — Is it science or is it snake oil? Here is an engineer’s perspective on the ongoing debate.

Disappearing Derivatives — What does it take to make good sounding audio equipment? This high-level treatment provides a useful metric for high-quality audio design.

Equipment Comparison — How do consumer audio, professional audio, and audiophile gear compare?

Damping Factor — Damping factor is a measure of an amplifier’s output impedance – here is one means of calculating it.

Crest Factor — How much power is needed for realistic music reproduction in a home environment?


Signal Processing

MASH Delta-Sigma — How does the noise shaping of the stable MASH delta-sigma converter compare to a standard delta-sigma converter?

Neural Networks — What will succeed FIR and IIR filters as the digital signal processing elements of choice?



VK-1 Dipole Loudspeaker — How good can a high-quality driver sound when it is freed from an enclosure?



Calculus of Variations — What is the quickest, the most cost-effective, the best?  The calculus of variations might have an answer.