Focusrite ISA 430 Mk II Analogue Channel Strip

The ISA 430 Mk II is the pinnacle of Focusrite's analogue channel strip technology, bringing every one of the company's classic designs together into a single comprehensive production tool. Alongside the transformer-based ISA microphone preamp sit a four-band EQ, a multi-format compressor, a discrete Class A gate and expander, a phase cancellation de-esser and a soft limiter, with internal routing and connectivity that no other channel strip can match.

The mic pre switches between 600Ω, 2.4kΩ and 6.8kΩ input impedances plus the original ISA 110 setting, so it gets the best from any microphone, from modern condensers to the most temperamental ribbons. The 'Air' switch drops a wire-wound inductor into the transformer's secondary, adding clarity and spaciousness without touching the EQ.

Three compressor modes - transparent VCA, Vintage Opto and Opto Limit - sit behind a Blend control that mixes the compressed and uncompressed signal, so the same source can be handled with clinical control or with the softer character of a classic opto design. The 'Listen' feature lets you solo exactly what the compressor, gate, expander or de-esser is reacting to, and inserts and monitoring points are available all along the signal chain.

Because those sections can be split apart and patched in any order, the ISA 430 Mk II works as up to four separate modular processors at once: mic pre, EQ, dynamics and, with the optional card fitted, a stereo A-D converter. The soft limiter sits ahead of that converter, so the ADC can never be driven into overload.