The Orban 622A/B are parametric equalizers of high professional quality. The 622A is a single-channel equalizer; the 622B is a dual-channel equalizer. Each channel contains four parametric equalization bands. Isolation of the two channels in the 622B is extremely high (greater than -90dB, 20-20,000Hz). Therefore, each channel may be used independently without danger of audible crosstalk. The 622 is equipped with rotary-type EQ controls providing up to 10dB of boost and better than 40dB of cut. The controls are non-reciprocal, providing musically useful "constant-Q" characteristics, and permitting the equalizer to be used as a notch filter. The center frequency and bandwidth of each band are continuously variable to enable precise control of the audio spectrum. Each channel of the 622 has an electronically-balanced bridging input and an unbalanced output which can be balanced by the addition of an optional output transformer. Input, output, and power line connections all contain effective RF filtering. l2dB of gain is available. AM potential overload points in the equalizer are monitored by an extremely fast "peak-stretching" overload detector, so that peak clipping can be detected and corrected before it becomes audible. The flexibility offered by the 622 makes it a particularly powerful tool in nearly all areas of audio: sound reinforcement, public address, recording studio, broadcasting, motion picture sound, dance bars (discos), theater... The 622 easily meets the quality, performance, and reliability requirements of the demanding professional, and is also well-suited for use in semi-pro or audiophile applications. The controls and features of the 622 are fully described in this manual. It will familiarize you with the unit's potential and enable you to imaginatively use the 622 for your specific installation and application. EQ Section Four bands, each with TUNING and BANDWIDTH control True parametric operation: non-interacting control over all three equalization parameters + l6dB, -infinity equalization range "Constant-Q" curves Each band tunes over 25:1 frequency range "Q" is variable between 0.29 and 3.2 Bands are totally non-interacting In/out switches for each equalizer band. Circuitry highly resistant to performance deterioration caused by control wear General l2dB available gain Very low noise and distortion High slew rate for minimum TIM (SID) "Peak-stretching" overload lamp warns of clipping anywhere in equalizer before distortion is audible Industrial-grade parts and construction Extremely easy service access RFI suppression on input, output, and power leads Balanced output optional (order retrofit kit as required)