Mic Input Gain; Line Input Gain; Instrument Input; Z In (Input Impedance) - Focusrite ISA Two User Manual

Mic Input Gain

The Gain switch adjusts the mic gain in 10 dB steps. Its range is either 0–30 dB or 30–60 dB when the 30–60
switch is pressed. An additional 0–20 dB of continuous gain adjustment is available using the Trim control.
Caution
To avoid an excessive jump in level, It is recommended that the stepped Gain switch is turned to
minimum before pressing the 30-60 switch.
Before starting a recording, set the Trim control to near its centre position. This will allow for some
gradual gain adjustment up or down without the use of the stepped control.
+48V
Pressing the +48V button applies phantom power to the Mic input XLR. This switch does not affect the Line or
Instrument inputs.
If you are unsure whether your microphone requires phantom power please refer to its handbook. Certain
microphones (most notably ribbon and unbalanced mics) could be damaged by applying phantom power.

Line Input Gain

The Gain switch adjusts the gain between -20 dB and +10 dB in 10 dB steps. Continuous gain adjustment of up
to 20 dB can be added using the Trim control.

Instrument Input

The Instrument input is via a standard 1/4" mono jack (DI) on the front panel. The level is set using the Trim
control and is continuously adjustable from +10 dB to +40 dB.

Z in (Input Impedance)

With the Mic input selected, pressing the Z In button steps through the four transformer preamp input
impedance options. The values are shown in the table.
Table 1. Mic Impedance
Low
ISA 110
Med
High
Tip
For information on impedance selection see
The Line input impedance is fixed at 10 kΩ and is not affected by the Z In switch.

Filter

Pressing the Filter button inserts the 18 dB/octave high-pass filter into the channel path; it is applied to
whichever input is selected. The High Pass Filter control allows the roll-off frequency to be set within the 16 Hz
to 420 Hz range.
Tip
The filter is useful for removing any unwanted low frequencies, eg., rumble transmitted through
floor-mounted mic stands, etc.
ISA Two User Guide
600Ω
1.4kΩ
2.4kΩ
6.8kΩ
Preamp Input Impedance
5
[10].