All user reviews for the Fairchild Recording Equipment Corporation 670

The Fairchild Audio 670 is a classic stereo compressor and is one that has been imitated quite frequently over the years.  It is an all analog unit and I'm not sure what types of connections it has since the one I have used was already racked in a studio.  It isn't a traditional rack mountable unit as it has its own shape.

UTILIZATION

The configuration of the Fairchild Audio 670 is easy to follow as the parameters found on this unit are pretty standard.  If you have used dynamic processor in the past I don't think that you'll have any trouble figuring out how to use the 670.  Each of the two channels has parameters for input gain, threshold, and time constraint.  Each channel also has a changeable meter that has a few different options.  Since this is an old piece of gear, I've never seen a manual for this but have also never been in a situation where I would have needed one.


SOUND QUALITY

The sound quality of the Fairchild Audio 670 is outstanding.  There is a reason that this has become such a highly sought after piece of gear and it is due to this outstanding tone.  It is a suitable compressor for just about any situation, but I like using it mostly for vocals, electric guitars, snare drum, and bass drum.  It has a crunchy tone and can really fill out a tone if it is lacking something.  While it definitely does the job of a traditional compressor, it also adds a certain something to your tone that can be described as punchy.  It is overall a great sounding compressor and is a tone that has been sought after by engineers over and over again.


OVERALL OPINION

All in all, the Fairchild Audio 670 is one of the best compressors ever made.  While they are now hard to find, they have a sound that has been used on classic recordings for years.  There is really nothing like the sound of this compressor and if I had a choice to only use a single compressor, the 670 would definitely be in the discussion.  While there are some decent plug-in emulations of the 660 and 670, there is nothing like the original and is a piece of gear that all engineers should try sometime.

If anyone has ever used this unit they will tell you it’s the best compressor ever made. Both the Fairchild 660(mono) and 670(stereo) are considered the King and Queen of all compressors. It was invented for the U.S. Army by a soviet broadcast technician Rein Nama. Fairchild Recording Equipment Co. commissioned him in 1959 to design the Fairchild for transmitting radio signals at a higher output rate for longer distances. It was also used in espionage to receive and record low-level radio signals being broadcast by the enemy.
It quickly became used in studios for recording when the word got out about its powerful compression and limiting capabilities. I have used them extensively in numerous studios and have suggested them to many clients. Whatever goes in comes out sounding thick and warm. That might have something to do with the 20 vacuum tubes and one rectifier tube. Talk about smoothing out those digital recordings, this is the ticket.
Don’t be confused about the difference between the UAD plug-ins that emulate the original vintage outboard rack version; there is no comparison whatsoever. The original Fairchild blows the plug-in version away!
Be ready to spend $30,000 or 24,000 Euros if you are thinking about claiming a piece of history. The Fairchild is like the engineers version of collecting rare artwork, but it also has function. And to most engineers it is just as beautiful as a classic painting.
The attack time at full limiting happens within 5,000th of a second. WOW !!!
The release times vary from .3 of one second to 25 seconds on a large round six-position switch on the front panel. You can really hear a difference when using this unit. It will spoil you, because after you get acquainted with the Fairchild, nothing will ever stand up to its superior sound.
The compression ratios start at 2:1 and can be raised up to 30:1 to be used as a limiter. All variables in between can be dialed in for the operators’ preference.
The controls on the front plate are easy to access. The 670 has 2 INPUT GAIN
Control knobs that attenuate at 1db per click. 2 THRESHOLD CONTROLS on the unit provide continuous variability. 2 TIME CONSTANT Switches that have six positions. This allows fixed and variable time constants for any type of recording or program material. 2 METERING SWITCHES with 3 positions for measuring plate current of each control tube, or as a limiting level indicator. The MODE SWITCH has A-B positions that can be used as 2 independent limiters. An ON-OFF switch on the Fairchild is indicated by a bright light, don’t forget to turn it on and let it the tubes warm up for at least a half an hour before using. This is important for getting the full benefits from the warmth of the tube sound quality.
I’ve used both the 660 and 670 for recording every instrument imaginable; vocals, drums, horns, bass and guitars really come alive when passing them through the unit at moderate compression levels (3:1, 4:1). Using it on overheads at high limiting levels (20:1, 30:1) give drums that big Led Zeppelin sound. The King of all compressors easily achieves mastering for program material or simply boosting a mix before mastering.
Re-recording tracks is an art perfected by the Fairchild. Regardless of how well you have recorded your music. By passing previously recorded tracks into the Fairchild the sound quality will absolutely pump up the volumes while maintaining dynamics. Re-recording each instrument may be time consuming but it’s worth it. Unless you’re a Zillionaire and can afford buying several Fairchild’s, re-recording is the next best option.
Back in 1959 the Fairchild sold for $600. The price went down for many years because of its large size and 65 lb. weight. It slowly faded out of popularity until the resurgence of classic vintage gear in the mid seventies. Now the King of all Compressors is a rare sought after collectors item that is worth every penny of its $30,000 price tag.

SPECIFICATIONS from Fairchild Recording Equipment Co. (Each channel, unless otherwise specified for 660)
INPUT IMPEDANCE: 600 ohms OUTPUT IMPEDANCE: 600 ohms
RANGE OF INPUT LEVEL: 0 dbm to +16 dbm. (-4 dbm to +16 dbm) (model 660)
OUTPUT LEVEL: +4 or +8 dbm (+27 dbm clipping point)
GAIN: 7db (16db Model 660)
FREQUENCY RESPONSE: 20 cycles to 15 kc +/- 1db.
SEPARATION: A-B position: 60 db vertical-lateral position: 40 db (does not apply to 660)
NOISE LEVEL: 70db below +4 dbm
LIMITING NOISES: Below audibility
INTERMODULATION OR HARMONIC DISTORTION: Less than 1% at any level up to + 18 dbm output (no limiting) Less than 1% at db limiting +12dbm output
ATTACK TIME: .2 milliseconds on positions 1, 2 and 6 .4 milliseconds on positions 3,4 and 5 (adjustable)
RELEASE TIME: Position 1: .3 sec Position 2: .8 seconds Position 3: 2 seconds Position 4: 5 seconds Position 5: Automatic function of program material: 2 seconds for individual peaks. 10 seconds for multiple peaks. 25 seconds for consistently high program level.
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: 115 volts, 50-60 cycles AC, 3 amps.
STABILITY: Unit maintains stability of gain, gain reduction and balance over the range of line voltage fluctuations from 100 to 127 volts. _
MECHANICAL DIMENSIONS: Standard 19" rack, 14" panel space, depth behind panel 11" _WEIGHT: Approximately 65 lbs.

TUBE COMPLEMENT: 8-6386; 1-6084; 1-5651; 2-12AX7; 2-12BH7; 1-EL34; 4-6973; 1-GZ34(5V4).

UTILIZATION

This must be one of the easiest compressors to use for any engineer, novice or seasoned vet. Everything that goes in comes out better; just be careful not to let it pump too much. The Fairchild has Input Gain, Threshold, and Time Constant(acts like release) knobs right on the front panel and these switches are big tough heavy duty knobs. When tweaking and turning them you can really feel the power. Makes you feel like super-hero engineer, especially when you hear the sound. The Meter Switch is chunky too and switches between limiting and plate current of the tubes. The 670 can go between stereo and dual mono via the Mode switch.




[b]SOUND QUALITY[/b]

The Fairchild is by far the King of warm sweet sound. I also have and use with no regret the LA2A and 1176 comp/limiters on a daily basis and I love them. Although the 660 and 670 reign supreme in sound quality and ease of use. Anything that can be recorded, mixed or mastered can be greatly enhance by passing the track into the original vintage Fairchild's.
The King of Spank is the Thump Squasher in compression mode and the Dynamic Destroyer in limiting mode. Anyone who has used one will tell you the sound quality is greater than all other comp/limiters!

[b]OVERALL OPINION[/b]

My all time favorite piece of gear! I've been using these units for about 10 years very successfully. How can you go wrong with so many tubes? Instant warmth, thickness and increase in dynamic range is instantly provided with little effort. The price may be high but the results are undeniable.