Buy a bag of mixed nuts, and what's always inside?
Cashews.
But, here's the thing. Cashews aren't nuts.
Botanically, a nut is a hard-shelled fruit where the shell doesn't split open at maturity — think walnuts, chestnuts, hazelnuts. A cashew is the seed of a tropical drupe, harvested from beneath what looks like a small pear-shaped apple. It's a seed. Not a nut. And yet it sits in every mixed nut bowl in the world, right there between the almonds and the pecans, like it absolutely belongs.
I think about this whenever someone asks me to explain FET and bipolar transistors because, strictly speaking, a FET isn't really a transistor at all.
The word transistor was coined in 1948 by John Robinson Pierce at Bell Labs, built from "transfer" and "resistor." It described exactly what the bipolar device does: transfer a signal across semiconductor junctions by controlling current. Bardeen, Brattain, and Shockley invented it; Pierce named it. That was the transistor. When FETs became practical years later, everyone just called them transistors too, because what else would you call them? But the operating principle is completely different. A bipolar is current-controlled — a small base current governs a much larger collector current. A FET uses an electric field at the gate to control a conducting channel. No junction. No base current. The field does the work. The guys who coined the name never imagined it.
Different sonic character too.
Bipolars tend to be fast and precise, with low noise in the right application. FETs have a different quality — smoother, more relaxed, with a way of handling signal that experienced listeners often describe as natural, even tube-like. Neither is simply better. The interesting work happens when you combine them thoughtfully, each device placed where its character serves the circuit.
That's what we've done in the PMG Signature Preamplifier and the PMG Signature DAC — a careful selection of device types, each placed where its particular nature serves the music best. The FETs bring what bipolars can't. The bipolars contribute what FETs won't. Like cashews in the bowl, the combination works precisely because the ingredients aren't the same.
Same category. Very different thing.
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