Every few years a new semiconductor technology arrives with impressive specifications and a lot of enthusiasm behind it, and the question we always ask is the same: does it actually sound better?
GaN — gallium nitride — transistors are the current example. These wide-bandgap semiconductors can switch much faster than the silicon MOSFETs that power most Class D amplifier designs, and the argument for them is fairly straightforward: faster switching could mean the modulation frequency gets pushed higher, output filtering might become simpler, and the high-frequency artifacts that have tended to plague Class D sound could be reduced. On paper it's a compelling story. The technology is genuinely interesting. But faster switching speed is only one variable in a very complex system, and it doesn't automatically translate into better sound.
Amplifier design is about synergy. The output devices, the feedback topology, the power supply, the output filtering, the input stage — all of it has to work together as a coherent whole. GaN devices switch faster, yes. But faster switching also means faster edge rates, which means higher-frequency noise components that need managing somewhere else in the circuit.
How much feedback you run, where you close the loop, how the output filter interacts with the speaker's impedance curve — all of that gets reexamined when you change the output devices.
A faster transistor in the wrong topology with the wrong feedback architecture can make things worse, not better.
This is why we don't simply grab the newest component and drop it into a design. The goal isn't to stay current with semiconductor trends — it's to find the combination of choices that produces the best sound with the best reliability. Two amplifiers using very different approaches can sound worlds apart even when their specifications look nearly identical on paper. That tells you the specifications aren't capturing the whole picture.
GaN is worth understanding. It earns a spot in a design when the entire design is better for it.
But only then.
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