{"product_id":"fairchild-670-stereo-compressor-limiter-310-vintage","title":"Fairchild 670 Stereo Compressor\/Limiter #310 (Vintage)","description":"\u003cp\u003eThe \u003cstrong\u003eFairchild 670\u003c\/strong\u003e is a variable-mu type compressor, using the vacuum tubes for reduction of gain right in the audio signal path, (no re-routing to a compression circuit).\u003cbr\u003e\u003cbr\u003eControls are paired for the left and right sides, and include a stepped Input Gain and continuously variable Threshold control, as well as a stepped 6-position switch for Attack and Release, that allow for four different combinations and two program-dependent settings. Set-screws on the back of the unit control the ratio; anywhere from 2:1 as a compressor to 30:1 as a limiter.\u003cbr\u003e\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eControls\u003c\/strong\u003e (all controls are dual)\u003c\/p\u003e \u003cul\u003e \u003cli\u003eInput Impedance: 600\u003c\/li\u003e \u003cli\u003eOutput Impedance: 600\u003c\/li\u003e \u003cli\u003eInput Levels: Normal line levels (+4 or +8 VU)\u003c\/li\u003e \u003cli\u003eOutput Level: +4 or +8 dbm line (+27 dbm after clipping point)\u003c\/li\u003e \u003cli\u003eGain:16db\u003c\/li\u003e \u003cli\u003eFrequency Response: 20 cycles to 20kc\u003c\/li\u003e \u003cli\u003eNoise Level: 70 db below +4dbm\u003c\/li\u003e \u003cli\u003eLimiting Noises: No audible thumps produced\u003c\/li\u003e \u003cli\u003eIntermodulation or Harmonic Distortion: less than 1% at any level up to +18dbm output (no limiting); less than 1% at 10db limiting and +12dbm output\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003e\u003cstrong\u003eAttack time\u003c\/strong\u003e (adjustable)\u003c\/p\u003e \u003cul\u003e \u003cli\u003e.2 milliseconds in positions 1, 2 and 6\u003c\/li\u003e \u003cli\u003e.4 milliseconds in positions 3 and 5\u003c\/li\u003e \u003cli\u003e.8 milliseconds in position 4\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003e\u003cstrong\u003eRelease time\u003c\/strong\u003e (from 10db of limiting)\u003c\/p\u003e \u003cul\u003e \u003cli\u003ePosition 1: .3 seconds\u003c\/li\u003e \u003cli\u003ePosition 2: .8 seconds\u003c\/li\u003e \u003cli\u003ePosition 3: 2 seconds for multiple peaks\u003c\/li\u003e \u003cli\u003ePosition 4: 5 seconds\u003c\/li\u003e \u003cli\u003ePosition 5: Automatic function of program material: 2 seconds for individual peaks, 10 seconds for multiple peaks\u003c\/li\u003e \u003cli\u003ePosition 6:\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003e\u003cstrong\u003eAutomatic function\u003c\/strong\u003e of program material:\u003c\/p\u003e \u003cul\u003e \u003cli\u003e.3 seconds for individual peaks\u003c\/li\u003e \u003cli\u003e10 seconds for multiple peaks\u003c\/li\u003e \u003cli\u003e25 seconds for consistently high program level.\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003e\u003cstrong\u003eCompression Ratio\u003c\/strong\u003e:\u003c\/p\u003e \u003cul\u003e \u003cli\u003eA function of the amount of limiting as well as setting of the two threshold controls which can be set to operate at ratios from 1:1 to 1:20\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003e\u003cstrong\u003eControls\u003c\/strong\u003e:\u003c\/p\u003e \u003cul\u003e \u003cli\u003eInput Gain control Step attenuator; 1 db per step\u003c\/li\u003e \u003cli\u003eThreshold Control continuously variable\u003c\/li\u003e \u003cli\u003eTime Constant Switch 6 positions, so as to provide fixed and variable time constants for any type of program material.\u003c\/li\u003e \u003cli\u003eMetering Switch 3 positions, so as to measure plate current of each of the control tubes, or as a limiting indicator\u003c\/li\u003e \u003cli\u003eOn-Off switch\u003c\/li\u003e \u003c\/ul\u003e \u003cp\u003eThe Fairchild 670 is the grandaddy of all analog compressors. Used on too many famous recordings to list, this was a studio mainstay throughout the heyday of vacuum tube equipment in the 1950s and 60s. Its use in Bill Putnam's United Western Recorders \u003cem\u003ealone\u003c\/em\u003e accounted for numerous hit records.\u003c\/p\u003e \u003cp\u003eThis unit is not for the meek, sporting 14 transformers and 20 tubes, with a single push-pull amplification stage, using high control voltage. The 670 weighs in at over 60 lbs. but you may not want to put that extra strain on your rack, when you can show off the impressive backside of this gorgeous unit, meticulously restored by our expert tech staff.\u003c\/p\u003e \u003cp\u003eThe Fairchild 670 was originally employed for its excellent capabilities in making stereo masters for vinyl records. By splitting the stereo channels into lateral and vertical segments, (via the LAT\/VERT knobs on the far right of the unit), and using two separate limiters to limit those channels, and then running them back together through a second matrixing network, the 670 allowed for maximum use of the stereo groove space, making records louder with less distortion. Listen to Rudy van Gelder's work on Blue Note or Vox Records for examples.\u003c\/p\u003e \u003cp\u003eWhile you may not be mastering for vinyl with this unit today, it is still a monster stereo compressor. No plug-in can match the sound of the original. There is only one Fairchild 670.\u003c\/p\u003e \u003cp\u003eVisit our \u003ca href=\"https:\/\/vintageking.com\/fairchild-660-670-compressor-limiter\"\u003eFairchild 660\/670 page\u003c\/a\u003e for more information.\u003c\/p\u003e \u003cp\u003e\u003cem\u003eVARIABLE-MU® is a registered trademark of Manley Laboratories, Inc.\u003c\/em\u003e\u003c\/p\u003e","brand":"Fairchild","offers":[{"title":"Default Title","offer_id":44450323562599,"sku":"101524","price":0.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0658\/8848\/5479\/files\/fairchild-670-stereo-compressor-limiter-310-vintage_101524_1_754d2034-7de2-48ae-82fd-f522fab32fed.jpg?v=1787092588","url":"https:\/\/vintageking.com\/products\/fairchild-670-stereo-compressor-limiter-310-vintage","provider":"Vintage King","version":"1.0","type":"link"}