The ISA 430 MKII represents the pinnacle of Focusrite’s analogue channel strip technology, bringing together all the classic designs in one comprehensive production tool. Augmented with additional features and flavours, alongside unmatched internal routing and connectivity, the ISA 430 MKII enables today’s recording professional to enjoy the unique sonic contribution of these heritage designs within one extremely versatile processor. Focusrite’s iconic status as the leading manufacturer of channel strips remains unrivalled.

Main features
Classic Focusrite transformer-based Mic-pre with variable impedance and ‘Air’ feature
Multi format Compressor; switch between Focusrite’s transparent VCA circuit and a vintage optical circuit
Unmatched flexibility with an incredible variety of insert points and variable signal path arrangements
Ability to function as 4 separate modular processors: mic pre, EQ, Dynamics and stereo ADC
Precision VU metering of input level, Insert 1 or 2 Return level,
Compressor gain reduction or Sidechain listen level (switched)
Classic Focusrite EQ design; an expanded version of the original ISA 110
Post mic pre output for the shortest possible signal path
Proprietary Focusrite discrete Class A VCA Gate and Expander designs
‘Listen’ feature for precise control over compression, gating, expansion and de-essing
De-esser design based on optical technology for lower distortion and transparency
Soft Limiter to avoid critical digital overload
Optional Stereo A/D – 24-bit 192 kHz Delta Sigma converter

Specifications
Line: Gain Range: +10dB to +40dB continuously variable
Input Impedance: >1MΩ
Mic: Gain Range: 0 to +60dB in 10dB steps
Input Impedance: Variable as follows: 600Ω, 1400Ω, 2400Ω, 6800Ω
EIN: -128dB with 150Ω terminating impedance at 60dB of gain
Noise: -97dBu
THD: 0.001% with -20dBu 1kHz input and 20Hz–22kHz bandpass filter
Compressor (VCA mode): Threshold Range: -28dB to +12dB
Ratio: 1.5:1 to 10:1
Slope: Soft knee
Attack: 100µS to 100mS
Release: 100mS to 7S, variable or auto (program dependent)
Compressor (Vintage Opto mode):

Threshold Range: -28dB to +12dB
Ratio: 1.5:1 to 5:1 in Comp mode
5:1 to 20:1 in Lim mode
Slope: Soft knee in Comp mode,
Hard knee in Lim mode
Attack: Fixed
Release: Fixed
Gate: 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
De-Esser: Threshold Range: 22dB
Frequency Range: 2K2 to 9K2
Ratio at centre frequency: 2:1
Limiter: Threshold Range: 20dBu
Ratio: infinite (Brick Wall)
Attack: Frequency dependent