Fairchild 670 specs??

[stratotak]

Anyone know where I can find the details of this compressor..I have found a data sheet that gave details of attack and release time,ratio range..but I cant find anything about filters value.Reason Is Im just messing with Reapers ReaComp and am trying to make a Fairchild 670 presets.Need to know things like the low pass and high pass filter values,knee size..and RMS ,pre-comp if any..

[[silent:arts]]

an official german measuring protocol can be found here

[SABOND21]

Can someone tell me - If I turn Threshold on position 1 what is ratio? Position's 2 ratio? etc... I would appreciate if someone will provide this info! Because I have found all info for Fairchild emulation except ration on Thresholds positions....

[SP2016]

Maybe this can help you.....

[SABOND21]

Thanks. 1 problem - I found the threshold positions' ratios, but in Logic Pro curves like in Fairchild 670 manual I can make choosing VCA compressor type only, with ClassA_U I can not. Does these Compressor circuits really gives an effect to the sound or I can choose VCA instead of ClassA_U and that's it?

[SP2016]

If you use Logic and try to duplicate settings of a genuine Fairchild 670 I wonder why you do not use the Fairchild 670 plug-in from Universal Audio.
Fairchild® 670 Compressor Plug-In | Universal Audio
That is the closest you can get to the original hardware unit and is very cheap (not only in comparison with the price of a real 670...)
I myself prefer the real 670, but these are hard to find now, so there is a large market of imitations.
These sell because practically nobody can compare with a real 670.
And believe me: They all sound very different !!

Finally: The 670 did not use VCA's, but a gain control amplifier tube circuit.
And even when you manage to get curves similar to 670 curves that does not mean that it will sound the same.
The Fairchild 670 was a LIMITER and no a compressor.
That means that the 670 just acts on a setable input level, the THRESHOLD.
Therefore there is no RATIO knob on the 670, but only that threshold switch.
And a switch for TIMECONSTANT, which is the selection of the release time.

Ratio settings are used in compressors.

[SABOND21]

Does these Compressor circuits really gives an effect to the sound or I can choose VCA instead of ClassA_U and that's it? Yes/No

[SP2016]

Originally Posted by SABOND21

Does these Compressor circuits really gives an effect to the sound or I can choose VCA instead of ClassA_U and that's it? Yes/No

Again: The Fairchild 670 is not a compressor, but a limiter !
Try to look around on this or other forums to learn what the difference is between a compressor and a limiter.

And for your YES/NO question: All compressor circuits give an effect to the sound.
That is why there are so many around and why these are used.

[SABOND21]

So - Yes. Thx!

[Matt Syson]

Hi
The curves show that it is a compressor.
A limiter input / output graph shows the output increasing linearly with the input until such a level that the 'limit' action kicks in at which point the output part of the graph line becomes horizontal rather than the 45 degree 'slope' of the input.
A limiter is 'simply' a compressor which has a ratio of near infinity to one and preset attack, and maybe release and threshold. All of the various 'parameters' are catered for in the design but only some have controls available to the operator.
As the 670 was designed for a particular purpose, the necessary parameters were known so they probably 'economised' on controls to stop 'operators' 'messing' things up.
Overmodulation of a transmitter or a disk cutting head is not normally an option as the results can be disasterous.
Matt S