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Focusrite ISA 430 Mk II

Focusrites ISA range is based around the original no compromise designs that recording console design legend Rupert Never built for Sir George Martin back in the mid-1980s, and every unit delivers the sought-after Focusrite Heritage Sound that lies behind thousands of top class recordings made over the intervening years in the worlds leading studios. With the ISA Range, you can put that sound at the heart of your own work and the ISA 430Mk II is the most sophisticated of them all: a complete channel strip in which every element can be used independently or patched in virtually any order including a classic mic pre, versatile EQ, VCA/optical compressor,expander/gate and de-esser.

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Category: Recording:Hardware:Channel Strips


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Inside the 2U rack-mount enclosure, the ISA 430 Mk II features a Lundahl transformer-input microphone preamplifier and equaliser based closely on the original ISA 110, itself based on the design for the A7971console by Rupert Neve, incorporating suggestions from George Martin and engineer Geoff Emerick. Virtually the only change is to give the mic pre a variable input impedance to get the best out of any microphone, modern or vintage, accurately or for effect. There's also a special air button that opens out the sound without EQ.

The equaliser itself features two separate parametric bands plus shelving low and high frequencies, high- and low-pass filters and the ability to switch individual EQ elements into the compressor side-chain for frequency-conscious compression, gate keying and other effects. Indeed, the four powerful processors that make up the ISA 430 MkII can all be used independently or patched into each other in a variety of ways for maximum versatility.

The ISA 430 Mk II is supplied with analogue outputs for full integration into a traditional audio path. But its as perfect a front-end fora digital system as an analogue one, and with that in mind there is an optional class-leading high-precision 192kHz, 24-bit 2-channel A-D card boasting 120dB dynamic range, that slots straight into the unit. Like the other sections of the ISA 430 Mk II, it can be used as part of the overall channel strip or employed independently.

Product Specifications


Gain Range: +10dB to +40dB continuously variable

Input Impedance: >1M Ohm


Gain Range: 0 to +60dB in 10dB steps

Input Impedance: Variable as follows: 600 Ohm, 1k4 Ohm, 2k4Ohm, 6k8 Ohm

EIN: -128dB with 150 Ohm terminating impedance at 60dB of gain

Noise: -97dBu

THD: 0.001% with -20dBu 1kHz input and 20Hz-22kHz bandpassfilter

Compressor (VCA mode)

Threshold Range: -28dB to +12dB

Ratio: 1.5:1 to 10:1

Slope: Soft knee

Attack: 100s to 100ms

Release: 100ms to 7s, variable or auto (program dependent)

Compressor (Vintage Opto mode)

Threshold Range:-28dB to +12dB

Slope: Soft knee in Comp mode, Hard knee in Lim mode

Attack: Fixed

Release: Fixed


Low Pass Filter: 18dB/oct from 400Hz to 22kHz

Parametric Section: Comprised of low-mid & Hi-midparametric, each with continuously variable boost/cut with centre detent,frequency sweep control with two ranges, and fully variable Q. Low-midfrequencies 40Hz to 400Hz (120Hz to 1k2Hz when x3 is pressed). Hi-midfrequencies 600Hz to 6kHz (1k8Hz to 18kHz when x3 is pressed

Shelving Section: Comprised of: high frequency shelf, withfrequency range steps of 1.5kHz, 3.3kHz, 6.8kHz and 15kHz (2.2kHz, 4.7kHz,10kHz and 18kHz when Hi Range is engaged), and low frequency shelf, withfrequency range steps of 20Hz, 56Hz, 160Hz and 460Hz (33Hz, 95Hz, 270Hz and655Hz when Hi Range switch is engaged)


Threshold Range: -40dB to +10dB

Gate Range: 0 to -80dB

Attack: switched fast or slow

Release: 100ms to 5s

Hold: 20ms to 4s

Expander Ratio: 0 to 5:1


Threshold Range22dB

Frequency Range2k2 to 9k2

Ratio at centre frequency2:1


Threshold Range: 20dB

Ratio: Infinite (Brick Wall)

Attack: Frequency Dependent


7.58kg (16.7lbs)


484mm (W) x 85mm (H) x 250mm (D)

19" (W) x 3.5" (H)x 9.8" (D)