Fairchild 660 (1950s–)

A mono vacuum tube compressor designed by Rein Narma, known for its fast attack and legendary status in studio recording.

Overview

The Fairchild 660 is a mono valve (vacuum tube) compressor built by Fairchild Recording Equipment Corporation in the mid-1950s. Estonian-born engineer Rein Narma designed it. Its attack is extremely fast - full limiting in 1/5000th of a second - and it started out as a broadcast limiter, there to protect transmission equipment. It has been out of production for decades. It is still consistently regarded as one of the best compressors ever made, and it turns up on countless classic recordings from the 1960s onward.

Specifications

Product type	mono valve (vacuum tube) compressor
Manufacturer	Fairchild Recording Equipment Corporation
Frequency response	40 Hz to 15 kHz ±1 dB
Noise level	70 dB below
Attack time	Extremely fast, full limiting in 1/5000th of a second
Release time	Variable, 0.3 seconds to 25 seconds
Threshold	Fixed DC threshold of 2 volts
Vacuum tubes	20 tubes (including dual sections)
Dimensions	19-inch rack, 14-inch panel depth
Weight	18.3 kg

Design

The 660 uses 20 tubes and a single push-pull stage of audio amplification. That stage delivers a high control voltage for precise gain regulation. It is built in a standard 19-inch rack format with a 14-inch panel depth. The unit was handcrafted, and the mechanical and electronic assembly was done with precision.

Context

The Fairchild 660 came out in the mid-1950s as a single-channel dynamics processor. It preceded the stereo 670 model. Broadcast and recording studios used it widely because it handled fast transients without distortion. Modern reissues and software emulations still follow it.

Market

Original units are highly collectible, with current market values reaching around $50,000. A reissue version has been released, handcrafted in Estonia by a skilled engineering team.