AI-generated product photo — not official manufacturer imagery.
Estimated price (community-sourced)
About the F1J
The First Watt F1J is an updated version of Nelson Pass's F1 current-source power amplifier, using state-of-the-art power JFET output devices in place of the original gain MOSFETs for improved high-frequency distortion performance, extended bandwidth, and about 1.5 dB more gain. Like the F1, it is a power transconductance amplifier (current-source amplifier) rather than a conventional voltage amplifier, optimized for sensitive full-range loudspeaker drivers and noted for its clarity, transparency, and precise control of voice coils. It operates in balanced single-ended Class A with no feedback, delivering roughly 10 watts per channel while each channel draws a constant 100 watts, and provides both balanced XLR and single-ended RCA inputs. Compared with the original F1, the F1J also has lower input impedance - approximately 30 kohm balanced and 15 kohm single-ended - and is recommended for use with preamps having ordinary to low output resistance for best high-frequency performance.
Specifications
Key Specifications
Full structured specifications are available to members.
Sign up to see full specificationsSee the full picture as a member
Create a free account to see where to buy, full structured specifications, similar components, and the systems that pair this with other gear.
Sign up free