Last watt. Of course with Nelson a transistor man well versed in high-power class A behemoths bad for most backs, his FirstWatt side hustle now part of the main Pass Labs production facilities in Auburn is purely sand not glass.
Aside from that, these FW circuits emulate the flea-watt ideal of simplicity. That means the lowest number of gain stages, little to zero negative feedback, pure class A bias and a sound-first tuning which prioritizes simple distortion of mostly 2nd-harmonic sometimes 3rd and nought past the 5th. This differs from most mainstream approaches which prioritize ultra-low THD but whose means to generate it leave high odd-order harmonic remnants.
Not conceptualized to generate high-volume turnovers, FirstWatt amps sell in low numbers and then discontinue to make room for new models. Nelson is very generous with sharing circuit schematics with his own DIYaudio forum. Nelson found this part so promising that over the years following his team chased down remaining global stock.
Once he had secured a long-term stash, he began dreaming up circuits around it. He was already familiar with the transistor type from his SIT1 thru 3 models. Once that company folded, his supply of these parts dried up and eventually the far more powerful Tokin version replaced it. If these were valve amps, the thermionic galleries would be aflutter-like orchid fanciers learning of a new species in faraway Polynesia or alcohol freaks hearing of caskets of cognac rescued from a shipwreck off the coast of France.
Ready to walk on the very obscure and esoteric side for a change? To outfit you in proper history attire, the FW catalogue is already on its 19th! Some were single-stage affairs where one gain stage generated both current and voltage gain. Some used step-up transformers for passive voltage gain.
