Fairchild Model 660 Tube Limiter/Compressor

Fairchild Model 660 Tube Limiter/Compressor

Mono Tube Limiter/Compressor with Selectable Attack/Release Time Constants, Custom-designed Transformers, and VU Metering

This is a special order item, please contact us for details: sales@stlaudio.co.nz

Fairchild 660: The Undisputed Heavyweight

 There are a handful of truly classic single-channel dynamics processors, but the Fairchild 660 tube limiter/compressor is the undisputed industry heavyweight. In the estimation of many seasoned recording, mastering, and broadcast engineers, the Fairchild 660 stands as the finest such unit ever made. Coveted by audio pros for its inimitably smooth, creamy, and natural-sounding dynamics control and the warmth, depth, weight, and character that it imparts to any program material, the iconic Fairchild 660 has been heard on countless classic recordings of the 1960s, ’70s, and beyond. Less than 1,000 were ever built, and today the originals are exceedingly rare — even more so if you’re seeking one in good working condition.

The legend, reborn

Designed in the late 1950s, the Fairchild Model 660 was, even by the mil-spec standards of the day, over-engineered to deliver a natural, organic-sounding compressed signal along with an unprecedented degree of control thanks to distinctive features such as attack times ranging from a whiplash-inducing 10,000th of a second and a selection of release times adjustable from 0.3 seconds to 25 seconds. With its beautiful compression characteristics, lightning-fast attack time, unique vacuum tube circuitry, military-grade build quality, and unparalleled versatility, the original Fairchild 660 is reverentially considered the granddaddy of dynamics processors. Now, the iconic tube limiter is back to reclaim the title in a meticulously handcrafted re-creation of the legend, true to the original in every aspect

Smart, program-dependent soft-knee compression

The buttery-smooth sound of the vocals on Beatles’ records is largely thanks to the original Fairchild Model 660, of which EMI Studios (Abbey Road) owned several. The 660’s sound is the result of a number of factors, including its discrete, handwired point-to-point circuitry infused with the beefy power of 12 tubes and custom-wound transformers. An inherent sonic attribute of this type of “variable-mu” dynamics control is the gentle, soft knee of the compression curve, with fast attack and fairly long release times. It’s also program dependent, so gain reduction starts at a very low ratio on small peaks and gradually increases to brickwall territory on very loud input signals. The Fairchild 660 is driven by a single push-pull stage of audio amplification and a very high control voltage, thus ensuring that the automatic gain-controlled amplifier never produces audible audio artifacts such as the thumps and pumping common to many limiting amplifiers. The 660 exhibits extremely low distortion and vanishingly low noise under all conditions, both as a through amplifier and under maximum limiting conditions.

The control set

Due to the 660’s unique architecture, its control set is somewhat different from that of most other dynamics processors. It is equipped with an input level control, a limiting threshold control, an attack/release switch that selects between six time constants, plus a limiting meter and metering selector switch. On the Fairchild, the DC threshold is adjusted via internal trim pots for adjustment over a wide range, from a seamless transition between compression and hard limiting to a harder, more pronounced knee. The compression ratio is dependent on the amount of limiting as well as the settings of the continuously variable front-panel AC threshold control, which can be set to operate at ratios from 1:2 to 1:30. The attack and release time constants are adjustable in six steps via per-channel front-panel switches:

• Position 1) 0.2ms/0.3s
• Position 2) 0.2ms/0.8s
• Position 3) 0.4ms/2s
• Position 4) 0.4ms/5s
• Position 5) 0.4ms/0.2s individual peaks, 10s multiple peaks
• Position 6) 0.2ms/0.3s individual peaks, 10s multiple peaks, 25s consistently high program levels

Indispensable at any stage of the recording process

The Fairchild Model 660’s delectable sonics, rock-star performance, and outstanding versatility make it indispensable at any stage of the recording process. It’s magic on vocals. Through the 660, bass, guitars, drums, pianos, and orchestral instruments all take on new life and are easier to place in the mix. And come mix time, many engineers simply keep a pair of them strapped across the stereo master bus to achieve assertive, radio-ready mixes that blast right out of the speakers. However, if your primary use will be mastering, we recommend you consider the 660’s stereo stablemate, the Model 670.

The ultimate tool for classic analog sound

Purpose-built for mastering, the Model 670 offers the ability to run its channels independently or linked for stereo operation, giving you tremendous flexibility for optimally employing mid-side (M-S) processing, an encode-decode process in which the mid and side signals, after being separated by a hardware or software matrixing network, typically require different dynamics processing. Whether you go with the 660 or 670, you can rely on your Fairchild to elevate the sound of your studio to world-class status. 

Fairchild Model 660 1-channel Tube Limiter/Compressor Features:

• The ultimate tool for classic analog sound
• Handwired point-to-point construction
• Tube-driven amplification
• Custom-wound transformers
• 6 selectable attack/release time constants
• Threshold, compression, and makeup gain controls
• VU limiting metering

STL Pro Audio is the exclusive NZ distributor for Fairchild Recording Equipment.