Fairchild Model 670 dual-channel tube compressor/limiter: large rack-mount unit with a metal front panel, VU meters, and rotary controls for time constant, threshold, and gain on each channel.

Model 670

$48,500.00
$48,500.00
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Fairchild Model 670 dual-channel tube compressor/limiter: large rack-mount unit with a metal front panel, VU meters, and rotary controls for time constant, threshold, and gain on each channel.
  • Fairchild Model 670 dual-channel tube compressor/limiter: large rack-mount unit with a metal front panel, VU meters, and rotary controls for time constant, threshold, and gain on each channel.
  • Model 670
  • Model 670
  • Fairchild Model 670 dual-channel tube compressor/limiter: large rack-mount unit with a metal front panel, VU meters, and rotary controls for time constant, threshold, and gain on each channel.
  • Model 670
  • Model 670
Model 670

Model 670

$48,500.00
$48,500.00
Condition Brand New
Specs Verified model facts
Checked against 1 listing
Verified
Use Professional studios and mastering/mix engineers who want the classic Fairchild variable-mu sound on a stereo bus, in dual mono, or on individual sources.
Requires appropriate audio and data cables, compatible monitoring, mounting, or power setup
In stock Ask a question

Specifications

Dual mono/stereo tube compressor · 120 or 240 volts, 60 cycles AC, 3 amps

General

Type Dual mono/stereo tube compressor
Channels 2 (dual mono or stereo)
Construction Hand-wired point-to-point, custom-designed transformers
Edition Faithful recreation (reissue) of the original Fairchild 670
Rack height (original design) 6U
Metering VU metering

Tubes & Transformers

Tube complement 8x 6386, 2x 12AX7, 4x 6973, 2x 12BH7, 1x E80F (or EF806), 1x 5651, 1x EL34, 1x GZ34
Tube count 20 tubes
Transformers (original design) 11 transformers and 2 inductors
Transformers (reissue) Custom-wound to original specifications; made larger to reduce tube wear

Dynamics

Time constants 6 selectable (positions 5-6 program-dependent auto release)
Attack time 0.2-0.4 ms depending on position
Release time 0.2 s to 25 s (6 positions, including 2 auto modes)
Compression ratio Variable, 1:2 to 1:30 (a function of the amount of limiting)

Audio Performance

Frequency response 40 Hz - 15 kHz +/- 1 dB
Gain +7 dB
Noise level 70 dB below +4 dBm
Input impedance 600 ohms balanced
Output impedance 600 ohms balanced
Input level range 0 dBm to +16 dBm
Output level +4 or +8 dBVU (+27 dBm clipping point)

Power

Power requirements 120 or 240 volts, 60 cycles AC, 3 amps

Fit and constraints

Professional studios and mastering/mix engineer… · 120 or 240 volts, 60 cycles AC, 3 amps

Intended use

Use Professional studios and mastering/mix engineers who want the classic Fairchild variable-mu sound on a stereo bus, in dual mono, or on individual sources. Its six time constants — including two program-dependent auto-release positions — and ratios that move from 1:2 to 1:30 let it range from subtle, transparent leveling to heavy, pumping compression, which is exactly how the listing characterizes it.
Not for Anyone with limited rack space or budget: the original design occupies 6U, contains 20 tubes and a large complement of transformers, and draws 3 amps at 120/240 V. Engineers who need a wideband mastering spec should note the published frequency response tops out at 15 kHz (+/-1 dB, per the manufacturer's partner page). Project studios that just want an occasional bus compressor will find modern variable-mu alternatives far more practical.

Constraints

Power120 or 240 volts, 60 cycles AC, 3 amps
ControlsSources conflict on transformer count: Gearnews describes the original as 11 transforme...

To use it

Required appropriate audio and data cables, compatible monitoring, mounting, or power setup

Questions

3 to ask before buying

Which connections, drivers, operating systems, and sample rates are supported by this exact revision?

Ask before you buy via contact. Confirm power, condition grade, and included items against the listing photos.

What cables, mounts, power supplies, or licenses are included?

Ask before you buy via contact. Confirm power, condition grade, and included items against the listing photos.

Is the current retailer listing new stock, demo stock, open box, or special order?

Ask before you buy via contact. Confirm power, condition grade, and included items against the listing photos.

Description

Product details

The Fairchild Model 670 is a two-channel vacuum-tube variable-mu compressor/limiter that can operate in dual mono or stereo, with six selectable time constants plus threshold, compression, and makeup gain controls. The current unit sold by Studio Economik is described as a faithful and meticulous recreation of the original Fairchild 670, built with hand-wired point-to-point construction, custom-wound transformers, and the original 20-tube complement (8x 6386, 2x 12AX7, 4x 6973, 2x 12BH7, 1x E80F/EF806, 1x 5651, 1x EL34, 1x GZ34). Compression ratio varies with the amount of limiting from 1:2 up to 1:30, with attack times of 0.2-0.4 ms and release times from 0.2 s to 25 s including program-dependent automatic-release positions. It presents 600-ohm balanced input and output impedances, a 40 Hz to 15 kHz (+/-1 dB) frequency response, and runs on 120 or 240 V, 60 Hz AC at 3 A. The original design also allowed independent control of vertical and lateral amplitudes for stereo disk mastering.

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