Fairchild 670 -

Here are some interesting facts about the Fairchild 670:

Unlike later VCA or optical designs, the 670 controls gain by varying the bias voltage on remote-cutoff pentodes (6386s), which changes their plate resistance — a smooth, non-linear, musical gain reduction. fairchild 670

: While the Fairchild 660 is a mono unit, the 670 is the dual-channel (stereo) version, capable of independent channel operation or Lateral/Vertical (Mid-Side) processing. Here are some interesting facts about the Fairchild

The 6 positions are approximate RC time constants, but the actual release varies with program material. Position 3 might release in 150 ms on a snare hit but 300 ms on a bass note. often cited in the sub-millisecond range.

: Extremely fast for a tube compressor, often cited in the sub-millisecond range.