The Fairchild 670 limiter is arguably one of the most famous and sought-after stereo compressors ever made. The AnaMod AM670 Stereo Limiter for buss compression, is the standard.
The magical way it adds density and dimension to a track or a mix has been demonstrated on many of the best-sounding records made in the last 50 years. For buss compression, the 670 Limiter is the standard by which all others are judged.
The AM670 is a faithful recreation of the classic sound and compression profile of the 670, using the AnaMod process to model the complex tube circuitry of the 670 and implement it entirely in the analog domain. Unlike a digital plug-in or processorbased outboard gear, there is no latency, and no A/D or D/A conversions to compromise the sound. All the functions of the original 670 have been condensed into three rack spaces.
Like the Fairchild 670, the AM670 has Left/Right (dual mono), and Lat/Vert (M-S encode/decode) modes of dynamics processing. In addition, AM670 also has a Stereo mode, which links sidechains of the two channels.
Classic Variable-Mu compression profile and vintage tone
Six 670 time constants plus two vocal- friendly variations
Three Modes of Compression
All analog - no latency or conversion
Standard 3U rack format
Input Impedance: 20K, balanced
Output Impedance: less than 50
Max. Output Level: +27dBu, balanced
Input Gain: -15 to +15 dB
Frequency Response: +/- 1 dB from 40Hz to 15kHz
Noise Level: better than 73dB below +4dBu, 0-30kHz
Limiting Noises: same level as a vintage 660 with GE five star 6386 tubes and properly balanced
Total Harmonic Distortion: level- and compression-dependent
Compression Ratio: Variable from 1: 1 to 20:1, level-dependent
Automatic Gain Control (AGC) Modes
Left/Right: Dual Mono (split) operation
Stereo: Left and Right channels are linked
Lat/Vert: Left and Right channels are Mid-Side (M-S) encoded, compressed separately, and decoded back to Left/Right