SE4021 Transistor Fairchild

The Fairchild SE4021 is a fantastic, high-gain, low-noise NPN transistor that excels in applications where high hFE is beneficial—making it an exceptional choice for fuzz pedals. While it’s not as commonly discussed as standard choices like the 2N5088 or BC549, this transistor’s gain characteristics and low 1/f noise make it an ideal candidate for vintage-style and boutique fuzz circuits. High hFE – A Dream for Fuzz Pedals One of the SE4021’s standout features is its extremely high hFE, which can range from 600 to well over 1000. This high gain translates to rich, sustaining distortion in fuzz circuits, making it an excellent option for anyone looking to push their pedal into smooth, sustaining saturation. Compared to other transistors commonly used in a Big Muff, the SE4021 offers tighter, more responsive dynamics, particularly in high-gain configurations. Pinout Differences – Take Note! A key consideration when using the SE4021 in a Big Muff or other fuzz circuits is its unusual pinout. Unlike the standard E-B-C layout of transistors like the 2N5088, the SE4021 follows a C-B-E pinout: • 2N5088 Pinout (TO-92) (Flat side facing you) E B C | | | 1 2 3 • 1 = Emitter • 2 = Base • 3 = Collector • SE4021 Pinout C B E | | | 1 2 3 • 1 = Collector • 2 = Base • 3 = Emitter This means that if you’re installing the SE4021 into a Big Muff PCB designed for a 2N5088, you will need to swap the Collector and Emitter leads to ensure proper operation. Noise Performance – Great for Sustain While fuzz circuits often thrive on gritty, raw tones, the low-noise characteristics of the SE4021 ensure that unwanted hiss and hum are kept to a minimum—making it a great option for cleaner, more defined sustain while still delivering that rich, high-gain fuzz character. Datasheet The original Fairchild datasheet is available in the 1969 Fairchild Semiconductor Integrated Circuit Data Catalog on pages 12-15, accessible here: https://archive.decromancer.ca/bitsavers.org/components/fairchild/_dataBooks/1969_Fairchild_Semiconductor_Integrated_Circuit_Data_Catalog/09.pdf Final Thoughts – A Must-Try for Fuzz Enthusiasts If you’re looking for a high-gain transistor that brings extra saturation, sustain, and character to your Big Muff or other fuzz pedals, the SE4021 is a fantastic choice. Just remember to swap the Collector and Emitter pins if using it in a standard NPN transistor layout. With its superb gain characteristics and low noise, it’s an underrated gem that deserves more attention in the world of guitar effects.