Fairchild 670 (Late 1950s)
A dual-channel vacuum tube compressor/limiter, originally designed in the late 1950s, renowned as one of the most iconic audio processors in recording history.
Overview
The Fairchild 670 is a dual-channel tube limiter/compressor developed in the late 1950s by Fairchild Recording Equipment. Known as "the grandaddy of all tube-based compressors," it features tube-driven amplification, selectable attack and release time constants, and custom-designed transformers. Less than 1,000 units were originally produced, contributing to its legendary status and rarity. It became a staple in classic recordings and is celebrated for its sonic sophistication and timeless design.
Specifications
| Product type | 2-channel tube limiter/compressor |
| Frequency Response | 40Hz to 15kHz +/- 1dB |
| Input Impedance | 600 Ω |
| Output Impedance | 600 Ω |
| Input Level Range | 0 dBm to +16 dBm |
| Separation | 60 dB (A-B position) |
| Dimensions (W × H × D) | 482 × 359 × 229 mm |
| Weight | 90 pounds (40.8 kg) |
| Vacuum Tubes | 20 |
| Noise Level | 70dB below +4dBm |
Design
The Fairchild 670 uses a Vari-Mu design with tube-driven amplification and custom transformers. It allows front-panel control of push/pull cathode balance, a rare feature for its era. The unit houses 20 vacuum tubes, including four 6BC8 and four 6386 tubes per channel, forming the core of its rich, musical compression.
Context
Developed in the 1950s by Rein Narma, the Fairchild 670 became the gold standard in studio compression, used by legendary artists and engineers. It is often cited as the most iconic and finest-sounding tube compressor in history, influencing countless modern designs. The original 670 has been faithfully recreated in limited numbers, with reissues available at an MSRP of $35,000.
Market
Due to its scarcity—fewer than 1,000 units ever made—the original Fairchild 670 commands extreme collector interest. One unit was listed on eBay for $350,000, reflecting its status as a holy grail of vintage audio gear.
eBay Listings
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.