| Tech Data - Components: |
 | AM 670 Specifications |
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Input Impedance: 20KΩ, balanced |
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Output Impedance: less than 50Ω |
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Max. Output Level: +22dBu, balanced |
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Input Gain: -15 to +15 dB |
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Frequency Response: +/- 1 dB from 40Hz to 15kHz |
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Noise Level: better than 73dB below +4dBu, 0-30kHz |
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Limiting Noises: same level as a vintage 660 with GE five star 6386 tubes and properly balanced |
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Total Harmonic Distortion: level- and compression-dependent |
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Compression Ratio: Variable from 1: 1 to 20:1, level-dependent |
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Automatic Gain Control (AGC) Modes |
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Left/Right: Dual Mono (split) operation |
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Stereo: Left and Right channels are linked |
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Lat/Vert: Left and Right channels are Mid-Side (M-S) encoded, compressed separately, and decoded back to Left/Right |
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Time Constants |
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1-6 are the classic 670 time constants |
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2a and 2b are variations on #2 |
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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. |
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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. |
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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. |
