AM670 STEREO LIMITER

• 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

• One Year Parts and Labor Warranty

  The Fairchild 670 limiter is arguably one of the most famous and sought-after stereo compressors ever made. 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.

AM 670 Specifications

Input Impedance: 20KΩ, balanced
Output Impedance: less than 50Ω
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

Time Constants

1-6 are the classic 670 time constants
2a and 2b are variations on #2
 
Position
Attack Time
Release Time
1
0.2ms
0.3s
2
0.2ms
0.8s
2a
0.2ms
1s
2b
0.2ms
2s
3
0.4ms
2s
4
0.8ms
5s
5
0.4ms
Auto, as in 670 #5
6
0.2ms
Auto, as in 670 #6


All specifications are subject to change without notice.


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