Fairchild 670 Compressor / Limiter Officially Returns With New Recreation

Hushed murmurs on the floor at the 2023 NAMM Show have given way to a full-scale announcement at the 2023 AES Convention. That's right, the Fairchild 670 is back with an official recreation!

To say that the Fairchild 670 is one of the most coveted pieces of gear in pro audio is an understatement. The tube compressor / limiter has earned this reputation, thanks in part to its warmth and versatile sound, as well as the scarcity and price of the original units. The brand only made 500 to 1,000 670s in the initial run, and there are very few of them left.

While there have been other reproductions in recent years (see UnderTone Audio's UnFairchild 670M II and Heritage Audio's Herchild 670), this new recreation comes from TELEFUNKEN Elektroakustik founder Toni Fishman. Toni has spent the past five years doing intense R&D and testing in an effort to create something as close to the original Fairchild as possible. The results are stunning.

The new Fairchild 670 utilizes the same dual-channel design, tubes, and custom-wound transformers as the classic compressor / limiter, and is built to the exact specifications of the original. For a full breakdown of features and what's going on inside the Fairchild 670, continue below.

Fairchild 670 Compressor Key Features:

- Dual mono/stereo operation

- Six selectable time constants

- Threshold, compression, and makeup gain controls

- VU metering

- Hand-wired point-to-point construction

- Custom-designed transformers

- Tube-driven amplification

Fairchild 670 Technical Specifications:

Input And Output Impedance: 600 Ω

Range of Input Level: 0 dBm to +16 dBm

Output Level: +4 or +8 dBVU (+27 dBm clipping point)

Gain: +7dB

Frequency Response: 40 cycles to 15 kc +/- 1dB

Noise Level: 70 dB below +4 dBm

Limiting Noises: Below audibility

Intermodulation Distortion: Less than 1% at any level up to + 18 dBm output (no limiting) Less than 1% at dBm limiting +12dBm output

Time Constant Attack And Release Times: (Note: Positions 5 and 6 release times are automatic function of program material)

Position 1) .2 ms / .3 sec

Position 2) .2 ms / .8 sec

Position 3) .4 ms / 2 sec

Position 4) .4 ms / 5 sec

Position 5) .4 ms / .2 sec individual peaks, 10 sec multiple peaks

Position 6) .2 ms / .3 sec individual peaks, 10 sec multiple peaks, 25 sec consistently high program levels.

Compression Ratio: A function of the amount of limiting as well as setting of the two threshold controls which can be set to operate at ratios from 1:2 to 1:30

Power Requirements: 120 or 240 volts, 60 cycles AC, 3 amps.

Controls:

a) 2 Input Gain controls: Step attenuator: 1 dB per step.

b) 2 Threshold Controls: continuously variable.

c) 2 Time Constant Switches: 6 positions so as to provide fixed and variable time constants for any type of program material.

d) 2 Metering Switches: 3 positions so as to measure plate current of each control tube, or as a limiting indicator.

e) Mode Switch: A-B positions: 2 independent limiters. Vertical-Lateral position: matrixing input and output, left and right in and out, limiting action vertical-lateral.

f) On-off switch

Installed Tubes: 8x 6386, 2x 12AX7, 4x 6973, 2x 12BH7, 1x E80F or (1x EF806), 1x 5651, 1x EL34, 1x GZ34

Learn more about the original Fairchild 670 and 660 over in the Vintage King Pro Audio Hall of Fame, and watch below to see how we restored one of the vintage units back to its former glory:

Interested in purchasing the new Fairchild 670 for your studio or want to find a vintage one? Contact a Vintage King Audio Consultant via email or by phone at 866.644.0160.