Fostex 3070 - Page 5

(6) INPUT
Due to unique design efficiencies this rotary control per¬
forms two functions simultaneously. While the threshold level
at the input of the VCA detect circuit is fixed at about -18dBV
(0.13V), by varying the input level you effectively vary the
threshold level. The total amount of gain reduction is deter¬
mined by the setting of the compression ratio slope and this
input level control.
At a nominal -lOdBV line level reference, the threshold is
obtained with the INPUT knob at scale 3^4, and most of the
audio signal is passing unprocessed (linear response). See
Figure 1.
Fig. 1
With the compressor ratio slope set at “:1 it is likely that
the detect limit LED will light, indicating 32dB of gain reduc¬
tion. It should be noted that this LED does not indicate over¬
load of the audio signal; there is an additional 32dB of system
headroom before the compressor/limiter circuit overloads.
(7)OUTPUT
This rotary control is for adjusting the output level of
the processed signal. In a nominal scale position of 4 to 5,
referenced to -18dBV at the detect circuit input, the signal
level present at the output jacks will be -lOdBV (0.3V).