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The Fairchild 660 and 670

Pro Audio Hall of Fame / Fairchild 660/670

The Fabled Fairchild Tube Compressor

The Fairchild 670 is the grandaddy of all tube-based compressors, and has joined the ranks of the Immortals due to its rarity, price, sophistication, and, above all, sound. Estimates vary as to how many were ever produced – somewhere between five hundred and a thousand – but regardless of original numbers, very few survive today. The remaining Fairchilds that that do live on command an enormous price tag, making them probably the single most expensive piece of mass-produced audio gear. And it all started in someone’s basement.

Sherman Fairchild, inventor of the Fairchild 660 and 670

The Humble Beginnings of a Legend

Rein Narma was a genius inventor born in Estonia, who escaped the ravages of World War 2 and emigrated to America while working for the U.N. During his career as an audio engineer in the 1940s and 50s, Rein was frustrated by the limitations of the gear then available, and was one of the founders of Gotham Audio Development in 1954, whose purpose was to build quality audio components for professional use. While at Gotham, Rein developed the plans for a compressor/limiter, which he took with him when Gotham folded and he started his own company.

Enter Sherman Fairchild, heir to the fortune of his father, (one of the founders of IBM), and a genius in his own right. Sherman had numerous inventions and companies, many of which involved his two passions, photography and audio recording. Sherman created Fairchild Recording Equipment Company in 1931 to manufacture professional audio and broadcast gear. Stories differ as to how Sherman had heard of Narma and his new compressor/limiter, but in any event Rein agreed to license the design to Fairchild, and Sherman hired him on as Chief Engineer of the company. Although he only stayed briefly with the company in the late 1950s, Narma left behind an awesome audio legacy, the Fairchild 660/670.

Pete Townshend of The Who

“Right the way through my studio career the Fairchild 670 was a staple in any commercial studio. These things were actually made for mastering I think, for use in vinyl cutting rooms. But in the mid-sixties and early seventies, they started to appear in almost every major studio in the UK. Chris Thomas who produced three of my best sounding solo albums used to rent them in, sometimes two. They were rolled out like secret weapons to bring an electric guitar to life or add punch to a snare drum or bass drum, or to squash an entire mix. They are huge and unwieldy and were rarely found in a permanent rack.

These days there are so many really excellent emulations of the 670 (the 660 is the mono version I believe) in hardware form that having an original Fairchild 670 is rather like preferring an original signed Picasso print over an equally beautiful one that does not bear his name. It looks like vanity or elitism. But what we know about vintage studio equipment is that it makes us feel different about what we do, and how we do it, in the studio. When we fire up a 670 we are following in a long line of studio process and tradition that reminds us that if we use these great vintage tools carefully, but audaciously, we might break new ground all over again.

There is a mystical air about a Fairchild 670, sorry, but that’s a fact. We are in classic Ferrari land here. Except the 670 is as American as a Pontiac GTO that was doing 0-60 in 4 seconds back in 1967 before Ferrari were even warmed up. If you find a studio with a Fairchild 670 two possible realities are revealed. One, the studio owner has been around for a very long time and had one of these beauties before they turned into museum pieces. Or, the studio owner is rich and purchased one a few months back. The prices are high these days, and emulations (even the UAD plug-in) are so damned good, so either way, the studio owner is very lucky or financially foolhardy.

In action, the 670 seems to do much more than it should be capable of. As a subtle level control, it works very well, without pumping. As an effect, to create energy in rhythmic music tracks, it is often surprising. Very rarely will I move to a different compressor once I’ve set up a 670. But I am lucky enough to be able to buy one and maintain it. Vintage King offers many very close emulations, some boutique creations that are expensive but cost much less than an original 670 or 660. And so the 670 is rare and expensive, but like classic Neve modules, it has inspired a whole group of electronics enthusiasts to try to equal it, or better it. That in itself is a testament to this great American compressor.

Now I have a VW Golf that will stay close to that Pontiac GTO, go around tight bends and use less fuel. But it isn’t 50 years old. Sometimes old is simply better.”

Pete Townshend

The Early Days of The Fairchild Compressor

The original design was the model 660, a single-channel compressor built around a series of RCA 6386 tubes. Approximately 800 of these were manufactured, with the first 10 units being hand-built by Narma himself. The first unit was sold to fellow New Jersey resident Rudy Van Gelder, who made great use of the compressor when cutting lacquer masters for Blue Note jazz records and Vox classical records. The second unit went to Olmsted Sound Studios in New York, where Jimi Hendrix would record a decade later. The third unit went to guitar legend Les Paul, another Jersey neighbor and audio pioneer. Not coincidentally, Narma made custom recording consoles for all three clients, including Les Paul’s “Monster” desk to complement his “Octopus” 8-track Ampex recorder.

Once the mono 660 got off the ground, Narma used the resources of the Fairchild Company to create a two-channel version in 1959. By literally doubling all of the tubes and wiring of the original, and adding a matrixing network to connect the two channels, the massive model 670 was born. With a full complement of 20 tubes, 11 transformers and 2 inductors in a 6-unit rack size, the 670 weighed 65 pounds. Not for the faint of heart!

Narma made custom recording consoles for all three clients, including Les Paul’s “Monster” desk to complement his “Octopus” 8-track Ampex recorder.

A Versatile Approach to Dynamic Control

The essence of the Fairchild 660/670 is very fast attack and slow release times. The fast attack was necessary in its role as a broadcast limiter, protecting the transmission tower from explosive transients that could burn up a transformer. This character was also well suited for mastering mono records. But the expansion into two channels is where the unit really shines. While the 660 had been designed primarily for broadcast, the 670 was intended for cutting stereo lacquer masters.

The 670 can process two stereo channels either as a left/right stereo pair, or as lateral and vertical components for stereo disc cutting. In this mode, the 670 splits the two channels via a matrixing network, separately limits them, then recombines them through another matrix to reconstitute the stereo signal. This method of processing allowed the 670 to maximize the use of the stereo groove space, making records louder with less distortion. This was a critical factor in the success of the design, as Fairchild was also trying to perfect a 45/45 stereo cutter head at the same time. And by using a Mid/Side recording technique for the two channels, mono-compatibility could also be preserved.

Despite its massive size and weight, the majority of components in the Fairchild limiters are not in the audio path, which is a single variable push-pull amplification stage between input and output transformers (exactly balanced in the stereo unit). The heavy hardware is for creating the very high control voltage, while the tube configuration provides compression and amplification, with very low levels of noise and distortion.