The Valley People GAIN BRAIN II was a single-channel, variable-ratio analogue limiter, compressor and ducker introduced by Valley People in1980. Developed as the successor to the Allison Research GAIN BRAIN I, it introduced a new approach to dynamic range control, combining Linear Integration Detection, Log Domain Processing and Peak Reversion Detector Correction with the company’s EGC 101 voltage-controlled amplifier. Designed for professional recording and broadcast applications, the Valley People GAIN BRAIN II provided adjustable attack, release, threshold and compression ratio controls, together with external sidechain operation and a 21-segment LED gain reduction meter.
Unlike conventional compressors that relied primarily on peak or RMS detection, the Valley People GAIN BRAIN II employed a proprietary detection system intended to respond more closely to the changing characteristics of musical waveforms. Its Linear Integration Detector used a variable integration time to control how the unit reacted to incoming signals, allowing short transients to be treated differently from sustained programme material. This approach was designed to achieve effective dynamic control without unnecessarily suppressing the natural variations in music and speech.
Central to the design was Valley People’s EGC 101 VCA, which provided the electronically controlled gain adjustment. Working alongside the detector circuitry, the VCA allowed the Valley People GAIN BRAIN II to operate across a range of compression and limiting settings while maintaining low distortion. The control circuitry incorporated logarithmic processing and peak correction, with the latter helping the detector respond to rapidly changing signal conditions.
The front panel provided independent controls for threshold, attack, release, ratio and gain. Threshold could be adjusted from -40dBv to +20dBv, while attack time was variable from 2ms to 200ms. Release could be switched between linear and logarithmic characteristics, with release times extending from 50ms to 5 seconds. The ratio control offered settings from gentle compression through to limiting, including an infinity-to-one setting, while a separate gain control provided output level adjustment.
An important aspect of the Valley People GAIN BRAIN II was its flexibility. Beyond conventional compression and limiting, the unit could be configured for ducking, using an external signal to control the attenuation of another audio source. This made it suitable for applications such as reducing background music beneath speech, as well as other situations requiring one signal to control the level of another.
The external signal input also allowed frequency-dependent limiting. By introducing an equaliser into the control signal path, the Valley People GAIN BRAIN II could be made more sensitive to selected frequencies without directly equalising the programme audio. This provided a means of controlling particular frequency ranges, including applications involving vocal sibilance or excessive low-frequency energy.
For stereo operation, two GAIN BRAIN II modules could be interconnected so their gain control behaviour was linked. The design also provided access to the VCA control circuitry, enabling additional processing configurations and external control applications.
Visually, the Valley People GAIN BRAIN II followed Valley People’s compact modular format, with a black front panel, rotary controls, toggle switches and a vertical 21-segment LED meter displaying gain reduction. It was designed for installation in the company’s TR-804 rack system, which could also accommodate other Valley People processing modules, including the KEPEX II.
The Valley People GAIN BRAIN II represented an important development in the company’s dynamics processing technology during the early 1980s. Its combination of proprietary detection circuitry, variable time constants, external control facilities and modular construction reflected Valley People’s approach to professional analogue signal processing.
The Valley People GAIN BRAIN II was available by 1980, following the formation of Valley People through the merger of Allison Research and Valley Audio. It formed part of the company’s new generation of modular dynamics processors, alongside the KEPEX II, and demonstrated the increasing sophistication of analogue compression technology at the beginning of the decade.
Features
- Single-channel analogue limiter, compressor and ducker.
- Proprietary Linear Integration Detection circuitry.
- Log Domain Processing and Peak Reversion Detector Correction.
- Valley People EGC 101 voltage-controlled amplifier.
- Continuously variable compression and limiting ratios.
- Adjustable attack, release, threshold and gain controls.
- Switchable linear and logarithmic release characteristics.
- Dedicated ducking mode with adjustable attenuation.
- External sidechain input for interactive and frequency-dependent processing.
- Stereo interconnection capability using two modules.
- 21-segment LED gain reduction display.
- Modular construction for the Valley People TR-804 processing rack.