Input; Mic Input Gain; Line Input Gain; Instrument Input Gain - Focusrite ISA428 MkII Mode D'emploi

Input Stage

Input

Pressing INPUT steps through each of the three inputs, as indicated by the corresponding LEDs. When the mic LED is lit, the
microphone input is active etc. Hence a mixture of microphone, line and instrument inputs may be selected across the four channels
simultaneously.

Mic input gain

With the mic input selected, the user has access to the full gain range in 10dB steps from 0dB to +60dB. The gain range is split
between two gain modes depending upon the status of the 30-60 switch.
Mode 1 Mic Gain Range 0-30
With the 30-60 switch off, the rotary gain knob operates over a gain range of 0dB to +30dB, the level of gain chosen being indicated
on the front panel by the outer arc numbers around the gain knob.
Mode 2 Mic Gain Range 30-60
With the 30-60 switch on (illuminated), the rotary gain knob operates over a gain range of 30dB to 60dB, the level of gain chosen
being indicated on the front panel by the outer arc numbers around the gain knob. An additional 20dB of gain can be applied to the
signal after the mic/line gain knob using the Trim knob. See 'Trim' control text below for full explanation.

Line input gain

With the line input selected, the user has access to gain settings ranging from –20dB to +10dB, indicated on the front panel by the
inner arc of numbers around the gain knob. The 30-60 switch is inactive when the line input is selected, as the gain range for Line
level input is restricted to –20dB to +10dB in 10dB steps.
An additional 20dB of gain can be applied to the signal after the mic/line gain knob using the Trim knob. See 'Trim' control text below
for full explanation.

Instrument input gain

With the instrument input selected, gain is applied to the input signal by using the trim control only, which allows +10dB to +40dB
of gain range. The level of gain chosen is indicated on the front panel by the outer arc of numbers around the trim knob. This input
is suitable for high impedance sources such as guitar or bass pickups (which may be connected directly without the need for an
external DI box) or vintage synthesizers with high impedance outputs.

Trim

The Trim control provides additional variable gain of 0dB to +20dB when Mic or line inputs are selected. The level of trim chosen is
indicated on the front panel by the inner arc of numbers around the trim knob.
Note: When using the instrument input the Trim control is used to adjust gain.
The additional 20dB of gain that can be applied to the Mic or Line signal is very useful for two reasons:
When high gain is required
The trim used in conjunction with the Mic gain of 60dB will give a total of up to 80dB of pre-amp gain, making it very useful for
getting good digital recording levels from very low output dynamic and ribbon microphones.
Three input options are provided to give compatibility with microphone, line or instrument level
sources.
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