Heritage Audio HERCHILD Model 670N The Heritage Audio HERCHILD Model 670N is a high-end dual-channel Vari-Mu tube compressor that combines the legendary sound of classic Fairchild compressors with modern features and enhanced usability. Designed for demanding mixing and mastering environments, it delivers the iconic musical compression character heard on countless classic recordings. Built around discrete Class-A circuitry, NOS tubes, and custom transformers, the 670N provides authentic analog tone with extended flexibility for modern workflows. Sound Character The HERCHILD 670N delivers the classic Vari-Mu sound—smooth, musical, and highly cohesive. Its program-dependent compression offers a gentle, progressive response, creating natural dynamic control without artifacts. The low end remains tight and stable, while mids and highs gain depth and presence through subtle tube saturation. The result is a dense, three-dimensional sound with excellent transient integrity and mix “glue.” Highlights ✔ dual-channel Vari-Mu tube compressor (stereo / dual mono) ✔ authentic Fairchild-style compression with modern design ✔ 4 × NOS 6BA6 tubes and 6 custom transformers ✔ discrete Class-A signal path ✔ 6 attack and release time constants ✔ continuously variable compression slope (DC threshold) ✔ advanced sidechain filtering options ✔ LAT/VERT mode for mid/side processing ✔ independent bypass per channel ✔ transformer-coupled make-up gain stage (HA-880) ✔ stepped controls for precise recall ✔ 19" rackmount (approx. 5U), premium build quality Typical Applications ✔ mix bus and drum bus compression ✔ mastering-grade dynamic control ✔ vocal and instrument glue ✔ mid/side processing for width and depth ✔ high-end hybrid and analog studios Technical Specifications ✔ type: dual-channel Vari-Mu tube compressor ✔ circuit: discrete Class A, tube-based ✔ tubes: 4 × NOS 6BA6 ✔ transformers: 6 × custom designs ✔ modes: stereo, dual mono, mid/side (LAT/VERT) ✔ attack/release: 6 time constants ✔ sidechain: multiple filter frequencies (e.g. 80 Hz – 5 kHz) ✔ I/O: 2 × XLR in / 2 × XLR out ✔ format: 19" rack, approx. 5U ✔ manufacturing: hand-built

Heritage Audio HERCHILD Model 670 The Heritage Audio HERCHILD Model 670 is a high-end stereo Vari-Mu tube compressor that faithfully recreates the legendary sound of the Fairchild 670 for modern studio environments. Designed for professional recording, mixing, and mastering, it combines classic tube technology with enhanced control and flexibility. Featuring a fully tube-based signal path with 22 tubes and 9 transformers, the HERCHILD 670 delivers an authentic reproduction of one of the most iconic compressors in audio history—enhanced with modern usability and precision control. Sound Character The HERCHILD 670 delivers classic Vari-Mu compression—smooth, three-dimensional, and highly musical. Its program-dependent compression features a soft knee and dynamically adapts to the input signal, ranging from subtle glue to powerful limiting. The result is a dense, cohesive sound with exceptional depth and balance. The tube circuitry and transformer design add harmonic richness, warm midrange, and an open yet controlled high-end—making it ideal for mix bus and mastering applications. Highlights ✔ stereo Vari-Mu tube compressor (Fairchild 670 recreation) ✔ fully tube-based design (22 tubes) ✔ 9 transformers for authentic analog signal path ✔ program-dependent compression with soft knee ✔ continuously variable slope (DC Threshold control) ✔ sidechain filter for low-frequency control ✔ 6 classic attack/release time constants ✔ 4 operating modes: dual mono, stereo link, LAT/VERT (mid/side), LAT/VERT link ✔ VU meters for gain reduction ✔ extremely high headroom and low distortion ✔ 19" rackmount (6U) Typical Applications ✔ mix bus compression (“glue”) ✔ mastering with analog character ✔ drum and instrument bus processing ✔ vocal and instrument dynamics control ✔ high-end analog and hybrid studio setups Technical Specifications ✔ type: stereo Vari-Mu tube compressor ✔ circuit: fully tube-based (22 tubes, 9 transformers) ✔ compression: program-dependent (Vari-Mu) ✔ frequency response: 20 Hz – 20 kHz (±1 dB) ✔ max output: +30 dBu clipping point ✔ THD: < 1% up to +18 dBu ✔ noise: < -82 dBu ✔ signal-to-noise ratio: approx. 120 dB ✔ input impedance: 2 kΩ ✔ output impedance: 600 Ω ✔ I/O: 2 × XLR in / 2 × XLR out ✔ format: 19" rack, 6U ✔ weight: approx. 13.3 kg

Heritage Audio GRANDCHILD 670 The Heritage Audio GRANDCHILD 670 is a high-end stereo Vari-Mu tube compressor in 500-series format, bringing the legendary Fairchild compression sound into a compact and modern design. Built for professional recording, mixing, and mastering environments, it combines iconic vintage tone with practical flexibility. As the “little brother” of the HERCHILD 670, the GRANDCHILD 670 delivers authentic Vari-Mu compression in a space-saving dual-slot module—without compromising sonic quality or musical response. Sound Character The GRANDCHILD 670 delivers classic Vari-Mu compression—smooth, dense, and musical. Its tube-based design provides natural, program-dependent compression with a soft knee and organic response. The result is a creamy, cohesive sound with added warmth, depth, and punch—ideal for bus and mastering applications. Compared to many Vari-Mu compressors, it remains relatively transparent, preserving the original tone while subtly enhancing cohesion and dynamics. Highlights ✔ stereo Vari-Mu tube compressor (500-series format) ✔ based on classic Fairchild / HERCHILD 670 design ✔ true Vari-Mu compression with 4 NOS 6BA6 tubes ✔ 3 custom transformers for authentic tone ✔ 5 selectable attack/release time constants ✔ continuously variable compression slope (DC threshold) ✔ wide range from subtle glue to strong compression ✔ sidechain filtering for low-frequency control ✔ VU meter for gain reduction ✔ true bypass switch ✔ dual-slot 500-series module Typical Applications ✔ mix bus compression (“glue”) ✔ drum bus and parallel compression ✔ mastering with analog character ✔ vocal and instrument processing ✔ high-end hybrid and 500-series studio setups Technical Specifications ✔ type: stereo Vari-Mu tube compressor (500-series module) ✔ circuit: tube-based (4 × NOS 6BA6) ✔ compression: program-dependent Vari-Mu ✔ frequency response: 20 Hz – 20 kHz (±0.5 dB) ✔ max output: +29 dBu ✔ THD: < 0.5% @ +24 dBu ✔ noise: < -78 dBu ✔ input impedance: 15 kΩ ✔ output impedance: 50 Ω ✔ power consumption: >200 mA per rail/slot ✔ format: 500-series, dual slot ✔ weight: approx. 1.12 kg