The Latest Amp from Nelson Pass: The First Watt F7

by The Audio Beat | July 25, 2016

elson Pass's most recent amplifier design is the First Watt F7 ($3000), a 25Wpc stereo model with fewer parts than any previous First Watt amplifier. Its two-stage push-pull JFET input/MOSFET output topology is an update of the earlier F5 amplifier. The F7 embodies many of Pass's core design tenets, including very wide bandwidth, low distortion and noise, and a large class-A operating region. The F7 uses no capacitors or transformers, apart from those in the power supply, and it employs modest amounts of negative feedback in concert with a small amount of positive current feedback to create an amplification circuit with an output impedance approaching zero, so the F7 can handle a wider range of speaker loads. "Of course you can achieve a similar effect with tons of negative feedback, but I think this is more elegant and sounds better," explains Pass.

"This is a different amplifier," he further explains. "The diversity of audio taste being what it is, not everyone will prefer it. [But] I presume that a certain segment of audiophiles will like it."

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