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By Nick Irving

You may not have heard the name before, but you know the sound.


When Paul Buff's Allison Research released the Kepex and Gain Brain in the early 1970's, studio recording was changed forever. Together, these two devices became 'the sound' of 1970's drums on chart-topping records worldwide.


Here we present a history of Allison Research, and in the follow-up article next month, Valley People.

Allison Research (logo)
Paul Buff
Pal Recording Studio


Electronics engineer Paul Buff opened Pal Recording Studio in Cucamonga, California, in the early 1960's. Buff designed and built the studio's console and 5 track tape recorder, and recorded a number of important early surf records at the studio, including 'Wipeout' by The Surfaris. Indeed, the California State Legislature has installed a plaque at the site where the studio once stood, crediting Pal Recording Studio as the birthplace of the surf music revolution.

The studio was also home to a young Frank Zappa, where he recorded a large quantity of his early material. Paul Buff, Zappa and Ronnie Williams recorded an album together, 'Breaktime', calling themselves The Masters. The quality of the sound achieved from Buff's equipment was a breakthrough for the time, and the studio was soon in high demand.

Zappa bought the studio from Buff in 1964 and renamed it Studio Z. Sadly, the studio was forced to close in 1965 as the building was being demolished in order for the the street to be widened.  Paul Buff used the opportunity to go into business manufacturing his audio designs for the emerging recording studio outboard equipment market. He named his company Allison Research (after his then wife), and set up operations at 7120 Sunset Boulevard, Hollywood California.


The KEPEX (Keyable Program Expander), introduced in 1970, was the first product from Allison Research.

The Kepex, an expander/gate, was originally intended to be used to 'clean up' noisey recordings. But Paul Buff also saw its potential to shape the dynamic envelope of sounds themselves. Engineers found this perfect for 'tightening-up' close-mic'd drums using the Kepex to attenuate the bleed from other drums and cymbals. The Kepex could also be used to create super-dry sounds, by attenuating room resonance in recordings. The inclusion of a 'key' input added even further functionality, opening up a whole world of envelope-controlled sound shaping!


Model numbers:
Kepex 500 = Kepex module
Kepex 501 = Kepex module in Console Mount box CM001
Kepex 508 = Eight Kepex modules in RM160 case
Kepex 516 = Sixteen Kepex modules in RM160 case

Gain Brain


The Gain Brain, model 700, was the second product produced by Allison Research, released in 1971. It's a FET (field effect transistor) compressor/limiter, which is the same basic gain-control technology as other famous compressors of the era: the UREI 1176 and ADR Compex.

Gain Brains are known for their super-punchy sound, amazing dynamic control, and their unique continuously variable adjustment between Peak Limiting and RMS Compression.

The Gain Brain is one of the earliest examples of a compressor in a card or module format. Together with its sister module, the KEPEX (Keyable Program Expander), they became the sound of 1970's drums.

Model numbers:
Gain Brain 700 = Gain Brain module
Gain Brain 701 = Gain Brain module in Console Mount box CM001
Gain Brain 708 = Eight Gain Brain modules in RM160 case
Gain Brain 716 = Sixteen Gain Brain modules in RM160 case


Allison Research soon moved from California to Nashville, joining up with another studio equipment manufacturer to become Valley People.

Article Part Two: A History of Valley People

Valley People (logo)
Paul C Buff

PAUL C. BUFF  (1936-2015)

Engineer, Inventor, Entrepreneur

We're sad to report that Allison Research / Valley People founder Paul Buff has passed away. He died at his home in Alabama in March 2015, surrounded by family. He was 78.

Paul Buff's Kepex and Gain Brain changed the way records are made, and the very sound of recorded music. But he didn't stop there. Paul went on to design and produce a number of revolutionary Photographic products.

Paul Buff was one of the great innovators of the twentieth century, and his loss is felt throughout the recording studio and photographic communities. His revolutionary designs are still being used in the world's top recording studios every day, some 45 years after their introduction. His photographic equipment company continues as strong as ever.


At One Flight Up Recording Studios we have 6 original Allison Research Gain Brain modules from the early 1970's.

The first 4 modules and their rack came from Sony Music Studios in Sydney, via former house engineer Simon Tonx.

Modules 5 & 6 were originally in another famous Sydney studio, Trafalgar Studios in Annandale (now closed). These modules would've been used on Cold Chisel's first studio album (1978) as well as early records from Midnight Oil and all the other great Australian bands and artists to have recorded at Trafalgar over the years.


Our expert studio tech Colin Abrahams re-capped, repaired and calibrated the 6 modules, and then replaced all their LEDs (remember, these were some of the very first LEDs ever made, over 40 years old). He then added the 'Trafalgar' modules to the 'Sony rack', installed Link switches for the 3 pairs of modules, as well as a power switch & indicator neon for the rack, and re-capped the rack's power supply. The chassis was spray-painted bright yellow (originally it was plain aluminium) to complete the makeover. (Note: this is not an Allison Research chassis, but a series of 6 Allison Research console-mount boxes housed, with power supply, in an aluminium rack).


Originally all the LEDs in the modules were red, but these days many other colours are available. When restoring our vintage equipment, we generally like to keep things as original as possible (except for electrolytic capacitors!), but we decided to bend the rules this time and, for a fun touch, made the Peak and RMS LEDS yellow and blue, respectively. It certainly makes for a colourful light show in the control room!


Colin's done a superb job restoring the Gain Brains, and we're proud to be the custodians of such amazing pieces of music history at One Flight Up.


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