Product Description
The Pass Labs First Watt SIT-4 Power Amplifier stands as a pinnacle of audio engineering, offering a rare and exquisite blend of vintage technology and modern precision. Designed by the legendary Nelson Pass, this amplifier embodies the essence of purity and musicality, setting itself apart from conventional amplifiers in the audiophile market. At its core lies the revolutionary Static Induction Transistor (SIT) technology, a hallmark of the SIT series amplifiers from First Watt. This unique transistor design brings forth a sonic signature that is often described as a harmonious marriage between the warmth of tube amplifiers and the speed and accuracy of solid-state circuits. What truly sets the SIT-4 apart is its unwavering commitment to sound quality and musical fidelity. Operating in single-ended Class A mode, it offers a pure and direct signal path that preserves the delicate nuances and dynamics of your favorite music. With a modest power output of 12 watts per channel into 8 ohms, the SIT-4 is not about sheer wattage; it’s about precision, detail, and a deeply engaging listening experience. This low-power design makes it an ideal match for high-efficiency speakers, ensuring that every note is delivered with clarity and finesse.
In terms of features, the Pass Labs First Watt SIT-4 leaves no audiophile desire unmet. It boasts custom-designed output transformers, finely tuned to extract the utmost performance from the SIT transistors. The inclusion of both balanced XLR and unbalanced RCA inputs offers flexibility for connecting various audio sources, while the soft-start power supply protects the amplifier and connected speakers from power surges. The aluminum chassis not only adds a touch of elegance to its appearance but also aids in effective heat dissipation, ensuring optimal performance over long listening sessions. Moreover, the user-adjustable bias allows enthusiasts to fine-tune the amplifier’s performance to suit their preferences and the characteristics of their speakers. For audiophiles who demand nothing but the best in sound and performance, the First Watt SIT-4 Power Amplifier is an unparalleled choice. It represents the pinnacle of craftsmanship, with a meticulous design that prioritizes musicality, clarity, and precision. Whether you’re rediscovering your favorite vinyl records or immersing yourself in high-resolution digital audio, the SIT-4 promises an audio journey like no other, where every note is rendered with the utmost purity and emotion.
The SIT-4 is the First Watt power amplifier using the industrial grade Static Induction Transistors. It is preceded by the groundbreaking SIT-1, 2, and 3 and follows their technical philosophy and construction. An important difference in the SIT-4 is the SIT device itself. The previous three designs used Silicon Carbide to make a custom vertical power Jfet with a low impedance Drain whose character nicely emulated a power Triode tube but directly operated at the current and voltage that would drive loudspeakers without the requirement for an output transformer. SITs lend themselves to high-quality audio performance with very simple Class A circuits with little or no dependence on other active circuit elements or negative feedback. The Common Source mode SIT-1 could do the job surrounded by only passive elements, and the SIT-2 required only bias from a current source. The SIT-3 upped the game with Common Drain design biased by a novel Pass circuit, MUFF (Mu Follower/Follower). The SIT-4 follows in the Common Source footsteps but ups the game with an industrial SIT. The SIT-1/2/3 gain transistors were rated at a few amps and about 50 watts of dissipation. This amplifier uses a Tokin THF51s rated at 600 volts, 30 amps, and 400 watts. As a practical matter, the limitations of the SIT-4 circuit are the size of the heat sinks. And this big Jfet manages a bandwidth of 50 megahertz… The circuit of the SIT-4 is simple. Q1 is a new-old-stock Toshiba 2SK170 which drives the Gate of the Q2 SIT, whose output is biased by a mu-follower current source Q3.
The SIT (Static Induction Transistor) series of power amplifiers from First Watt stands out as a unique and innovative offering in the audiophile market. These amplifiers are characterized by their utilization of Static Induction Transistors, a technology that brings a rare and vintage flavor to modern audio systems. Designed by the legendary Nelson Pass, the SIT series harks back to the early days of transistor amplification, providing a sound signature that is often described as remarkably smooth, warm, and dynamic. What sets the SIT series apart is the meticulous attention to detail in its design, focusing on delivering a pure, uncolored sound with a touch of vintage charm. These amplifiers are not about raw power; instead, they excel in presenting music with nuance, texture, and a sense of musicality that captivates audiophiles seeking a more intimate and engaging listening experience.
One of the key features of the SIT series is the use of a single-ended Class A topology, known for its simplicity and purity of sound. These amplifiers are not concerned with pushing high wattage; rather, they focus on the quality of amplification. With relatively low power outputs compared to mainstream amplifiers, the SIT series emphasizes the importance of efficient and accurate power delivery, resulting in a musical presentation that is detailed, transparent, and emotionally engaging. This emphasis on quality over quantity makes the SIT series an intriguing option for those who prioritize musicality and a more organic sound reproduction. In a market saturated with high-power, complex amplifiers, the First Watt SIT series stands as a refreshing alternative for audiophiles who appreciate the artistry and craftsmanship behind true high-fidelity sound.
