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Focusrite ISA428 MKII 4-Channel Microphone Preamp
Focusrite's ISA mic preamps can be traced back to 1985, when console designer Rupert Neve was asked by Sir George Martin to create new modules for the console at AIR Montserrat. The modules he created included the legendary ISA110, on which all ISA microphone preamps are based. With their characteristic Lundahl LL1538 input transformer, along with one concession to modernity—variable input impedance—ISA mic preamps are very much the same as they were 30 years ago. But today, instead of solely gracing the consoles at AIR, ISA mic pres are at the heart of hundreds of hits made in leading studios and by leading engineers, artists and producers, across the world.

Now in its second generation, the ISA 428 MkII incorporates four of Focusrite's renowned mic pres in a simple-to-operate 2U enclosure, placing four mic preamps, instrument inputs and line ins at your fingertips. The original Focusrite mic pre was designed to suit the microphones of the time; today's model makes a small change, adding three additional input impedances to the classic ISA110 setting, allowing you to match any microphone, old or new, and access a wide range of sounds, from the character and warmth of a vintage mic to the clear transparency of a modern design. Or, you can experiment and bring out just the qualities you want.

In addition to the mic inputs, there are four front-panel instrument inputs, making the ISA428 MkII ideal for overdubs in the control room with no need for a DI box. On the back: four line inputs and switchable insert points on each channel to allow routing via external signal processors. There's also a versatile, vintage design variable high-pass filter to control what's going on at the bass end. And finally, accurate, 6-LED meters to tell you exactly what's going down. Optionally, available for the ISA428 MkII is a precision eight-channel A-D converter with 122dB dynamic range and superb jitter performance (sold separately)—ideal for simple interfacing with your DAW.
 
UPDATE: Now comes with Brainworx bx_console Focusrite plug-in
This awesome plug-in recreates the analog signal paths of Focusrite’s revered ISA 110 and ISA 130 modules, which were a part of the Focusrite Studio Console. Designed and coded by the DSP geniuses at acclaimed software house Brainworx, the new bx_console Focusrite VST/AU/AAX plug-in for Mac and PC faithfully captures the sound, feel and styling of the original iconic hardware.

If you purchased any Red, RedNet or ISA solution from January 2020 on, you will have the plug-in available in your Focusrite account as long as you’ve registered your product.

Focusrite ISA428 MKII 4-Channel Microphone Preamp

$1,999.00Price

  • Four ISA series transformer-based preamps

    - ISA series mic preamps have been the producers' choice on countless hit records over the last two decades.

    Eight-channel optional A-D converter

    - Four additional A-D converter inputs allow eight channels of high quality conversion, with a dynamic range of 122dB and jitter performance below 250 picoseconds.

    Selectable impedance

    - Ideal for mic matching or extended microphone creativity. Settings include the 'Vintage ISA110' setting, providing the original focusrite signature sound.

    Four front panel instrument inputs

    - Instant access on the face of the unit - no separate DI box required.

    Dedicated analogue insert points

    - Switchable insert points are featured on every channel, allowing routing (between preamp and output) through additional external processing.

    Accurate LED meters for every channel

    - Clear metering designed to catch even the fastest and most elusive of transients.

  • Mic inputs

    Frequency Response At Minimum Gain (0dB) (Mic)

    - -0.35dB at 20Hz and –3dB at 122kHz

    Frequency Response At Maximum Gain (60dB) (Mic)

    - –2.5dB at 20Hz and –3dB 103kHz

    Gain Range (Mic)

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

    Maximum Headroom (Mic)

    - 7.4dBu

    Noise EIN (Mic)

    - -126dB (measured at 60dB of gain with 150O termination and 20Hz/22kHz bandpass filter)

    Noise At Main Output With Unity Gain (Mic)

    - -98dBu (measured with a 20Hz/22kHz bandpass filter)

    SNR (Mic)

    - 123dB (relative to max output 25dBu) 120dB (relative to 0dBFS ( 22dBu)

    CMRR (Mic)

    - 88dB

    Input Impedance, Variable (Mic)

    - 600O, 1400O, 2400O, 6800O

    Line inputs

    Frequency Response At Unity Gain (0dB) (Line)

    - -0.3dB at 20Hz and –3dB at 94kHz

    Gain Range (Line)

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

    Maximum Headroom (Line)

    - 25.4dBu

    THD N (Line)

    - 0.002 (measured with 4dBu input signal, 0dB gain setting, with a 20Hz/22kHz bandpass filter)

    Noise At Main Output With Unity Gain (Line)

    - -91dBu (measured with a 20Hz/22kHz bandpass filter)

    SNR (Line)

    - 116dB (relative to max output 25dBu) 113dB (relative to 0dBFS 22dBu). Input Impedance: 10kO

    Frequency Response At 10dB Gain (Instrument)

    - -0.2dB at 20Hz and 0dB at 200kHz

    Frequency Response At 40dB Gain (Instrument)

    - -3dB at 20Hz and –3dB at 38.4kHz

    Instrument inputs

    Gain Range (Instrument)

    - 10dB to 40dB continuously variable

    Maximum Headroom (Instrument)

    - 11.5dBu

    Noise At Main Output With Minimum Gain ( 10dB) (Instrument)

    - -95dBu (measured with a 20Hz/22kHz bandpass filter)

    Input Impedance (Instrument)

    - >1MO

    High-pass filter

    Roll Off

    - 18dB per octave 3 pole filter

    Frequency Range

    - 16Hz to 420Hz (continuously variable, measured at the 3dB down point)

    Front and rear connectivity

    Analog Audio Outputs (Outputs 1-4)

    - 4 line XLR outputs on rear panel, 4 insert send 1/4” TRS jacks on rear panel

    Other I/OIEC

    - power input connector 100Vac – 240Vac

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