The Orban Model 422A/424A Compressor/Limiter/De-Esser is an integrated AGC device of highest professional quality. It can perform compression, peak limiting, and vocal de-essing functions simultaneously with unusual freedom from side-effects. It can thus serve either as a general-purpose no-compromise compressor/limiter, or as a complete dynamic processor for conditioning vocals. However, it is not optimized for overmodulation protection of broadcast transmitters, and the Orban OPTIMOD-AM, -FM, or -TV should be used in such applications. The flexibility and natural sound of the 422A/424A make it applicable in other areas of professional audio as well: recording studios, sound reinforcement, public address, motion picture sound, etc. The product is available in both single- (422A) and dual- (424A) channel versions. (For clarity, only the k2kA will be referenced in this manual.) The dual-channel version is equipped with a coupling switch which forces the gain of both channels to be equal, tracking the channel demanding the greatest amount of gain reduction. This preserves correct imaging in stereo applications. However, the stereo coupling switch does not couple the operating controls, and these are ordinarily set identically in stereo operation. Attack and release times are both program-controlled, but can be scaled faster or slower by means of front-panel controls. This results in maximum flexibility, plus extremely natural sound over a wide range of control settings. The klkA Compressor is equipped with electronically-balanced inputs and outputs and is compatible with the levels and impedances found in both professional and semi-professional applications. RF suppression applied to the input, output, and power leads enables use in relatively high RFI fields such as those common in broadcasting. The controls and features of the 424A Compressor are fully described in this manual. It will familiarize you with the unit's potential and enable you to imaginatively use the 42^A for your specific installation and application. Because the front-panel controls are marked in a familiar way, you may be tempted to jump right in without reading the manual. However, if you take the time to review the Description And Function Of Front-Panel Controls and Operating Instructions in Part C, you will find that there is "more than meets the eye" inside the 424A, and that the time you take reading the manual will be well-rewarded by a greater understanding of the unit's potential.