Field effect transistors, also known as FET, are a type of dynamic audio effect. FET compressors are devices from the family of dynamic audio effects. Their design maintains more transients, which adds an extra punch in contrast to the variable. These extra punches are known as mu and VCA compressors. Generally, the slowest attack time on the FET compressor is much faster than the fastest attack time variable mu compressor. The first field-effect transistors came about when small transistors began to replace larger tubes. Field-effect transistors are very warm and rich regarding sound character. In a FET compressor, the sidechain is a result of the gain reduction phase. Hence, it is extremely program dependent.
FET Compressors: a Popular Example
A popular FET compressor design was the 1176 amplifier by UREI. It gained its popularity because it offered extremely quick attack and release times. Similarly, it also offered a wide range of sound characters that varied between subtle, near-transparent compression, to all-out drive and distortion. The 1176 limiting amp used artificial reverberation with echo chambers for commercial use. In addition, its selling point had an extremely fast attack and release times. This audio compressor added character, attitude, and vibe to everything that ran tough its circuits. Since the 1176 amplifier was physically unique, people often used with the compressor turned off, just for the added appearance.
More on the 1176
The 1176 amplifier had unique features like push-button selectable ratios for both compression and limiting. It also had an all-buttons-in mode that allowed all the ratio buttons to depress simultaneously, achieving a peculiar sound. In brief, the device’s amps and transformers provided a unique quality to anything that went through them.
After UREI launchd the 1176 amplifier, many others attempted to replicate the original version. The Universal Audio version, known as UAD, was one of the closest replicas. In this version, the signal is perceived after gain reduction and used to enhance stability. The UAD uses feedback in each of its amplifier phases. For the replica to be exact, UAD had to replicate the original integral output transformer, which offered a feedback signal to the final line output amp circuity.