The First Watt SIT-5 is a single-ended Class A stereo power amplifier designed by Nelson Pass, representing the fifth generation of First Watt amplifiers built around Static Induction Transistors (SITs / VFETs). Following the SIT-1, SIT-2, SIT-3, and SIT-4, the SIT-5 utilizes high-power Tokin THF51S Silicon SITs—industrial-grade devices rated at 600V, 30A, and 400W—to deliver 10 watts per channel into a 10-watt amplifier envelope. Operating in a single-stage, zero-feedback Common-Source configuration, the SIT-5 closely emulates the transfer characteristics and dominant second-harmonic spectrum of a single-ended triode (SET) tube amplifier, driving loudspeaker loads directly without requiring an output transformer. By combining massive power handling headroom with tube-like harmonic purity, high bandwidth, and exceptional dynamic control, the SIT-5 provides an ultra-transparent, natural, and fluid listening experience.
| Frequency response | 5 Hz až 200 kHz (-3 dB) |
|---|---|
| Input impedance | 100 kΩ |
| Power consumption | 200 Watts |
| Fuse | Typ 3AG pomalá (2,5 A pre 120 V AC / 1,25 A pre 240 V AC) |
| Gain | 19 dB |
| Noise | 30 µV nevážený, 20 Hz – 20 kHz |
| Distortion @ 1 Watt | 0,07 % |
| Damping Factor | 25 |
| Output Power @ 8 Ω | 35 Watts @ 1 % THD |
The First Watt brand represents a unique, visionary project by the legendary audio engineer Nelson Pass, founded in 1998 with the aim of exploring the boundaries of purist amplification without the compromises of the commercial market. The brand builds on Dick Olscher’s famous idea that it is precisely the first watt of power that is most important for overall musicality. If an amplifier does not sound natural and detailed at the very first watt, enormous power output in the hundreds of watts loses its meaning. First Watt specialises exclusively in low-power amplifiers operating in pure Class A with an output of up to 25 watts, which utilise exceptionally simple circuit designs with minimal or zero negative feedback.
Thanks to their simple circuitry and an emphasis on the top-quality of individual transistors, First Watt amplifiers deliver exceptional micro-dynamicsdynamics, captivating detail and a silky naturalness that is often compared to the finest valve designs, yet with the absolute reliability of solid-state technology. Each model from Nelson Pass’s workshop represents a unique concept, whether it involves the use of special JFET and SIT transistors or a current-source circuit without negative feedback. First Watt amplifiers are designed for discerning audiophiles with highly sensitive loudspeakers who seek subjective perfection, absolute fidelity and uncompromising musicality.
Manufacturer information (GPSR)
Manufacturer
Pass Laboratories
13395 New Airport Road, Ste G Auburn, CA 95602 (530) 878 5350 USA