Two channels of classic Focusrite mic pres

Focusrite's ISA Two brings together a totally independent pair of classic ISA microphone preamps from the original ISA 110 module, combining the best of traditional solid-state electronics with the original input transformer specified by Rupert Neve – the Lundahl LL1538.

Each mic pre has the option of mic, line or the front-panel instrument input, with variable input impedance to ensure you are getting the best performance from the source. Up to 60dB of gain is available on the first four-position rotary and gain range switches, with a further +20dB of continuously variable trim, meaning a huge 80dB of gain is available should it be required. The high-pass filter features variable cut-off frequency between 16 and 420Hz. A pair of 8-segment LED meters show peak signal level in dBFS, while a rear-panel pot allows calibration to suit your A-D converters. Rear-panel insert points allow the use of inline processors such as compression.

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Classic ISA mic preamp design featuring Lundahl LL1538 input transformer
Front-panel instrument inputs
Dedicated TRS line input socket with front-panel switch
Switchable input impedance including classic ISA 110 setting
Dedicated insert points
User-calibrated peak-level meters

specifications

Mic Input Response


Gain range (Mic)

0 dB to 60 dB in 10 dB steps, plus 0 dB to 20 dB continuously variable trim

EIN (Mic)

Measured at 60 dB of gain with 150 O source impedance and 22 Hz-22 kHz band pass filter -127 dB

Noise (Mic)

Noise at output with unity gain (0 dB) and 22 Hz-22 kHz band pass filter -97 dBu

Frequency Response (Mic)

At minimum gain (0 dB)-0.5 dB at 10 Hz,?-1 dB at 135 kHz, relative to 1 kHz

At 60 dB gain (Mic)

-6 dB at 10 Hz, -1 dB at 115 kHz, relative to 1 kHz

Crosstalk Channel to Channel (Mic)

Mic input, with I/P = 0 dBu, gain = 0 dB @ 1 kHz input to channel A, channel B output = -85 dB

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Line Input Response


Gain range (Line)

-20 dB to 10 dB in 10 dB steps, plus 0 dB to 20 dB continuously variable trim

Input Impedance (Line)

10 kO from 10 Hz to 200 kHz

Frequency Response (Line)

At minimum gain (0 dB)-0.3 dB at 10 Hz, -1 dB at 80 kHz, relative to 1 kHz

Crosstalk Channel to Channel (Line)

Line input, with I/P = 0 dBu, gain = 0dB @ 1 kHz input to channel AChannel B output?= -91 dB

Instrument Input Response


Gain range (Instrument)

10 dB to 40 dB continuously variable trim

Input Impedance (Instrument)

2 MO

Noise (Instrument)

Measured with 22 Hz-22 kHz band pass filterMinimum gain ( 10 dB) = -95 dBu

Frequency Response (Instrument)

At minimum gain ( 10 dB)-0.1 dB at 10 Hz,?-1 dB at 115 kHz, relative to 1 kHz

At maximum gain ( 40 dB) (Instrument)

-2.5 dB at 10 Hz, ?-1 dB at 110 kHz, relative to 1 kHz

High-Pass Filter


Roll-Off

18 dB per octave (3 pole filter)

Frequency Range

Continuously variable from 16 Hz to 420 Hz (-3 dB)

Weight and Dimensions


W x D x H

480 mm x 280 mm x 44 mm

Weight

3.7 kg

Downloads

User Guide


ISA Two User Guide