Focusrite ISA428 MkII Rackmount 4-Channel Microphone Preamp

TheFocusrite ISA428 MkII is a four-channel microphone preamplifier that incorporates Focusrite’s transformer-based preamps. It offers selectable input impedance, direct instrument inputs, and the option for eight channels of high-quality analog-to-digital conversion. This unit serves as an ideal front end for audio professionals, accommodating both digital and analog recording needs.

The ISA microphone preamp is renowned for its ability to provide transparency while imparting a subtle warmth, a characteristic attributed to transformer core saturation. The inclusion of a variable impedance circuit enables users to achieve an optimal match between the preamp and any microphone, as well as to explore various settings creatively to manipulate the microphone’s sound.

Focusrite preamps boast an exceptionally wide frequency response, approaching 200 kHz at the upper end, ensuring precise phase response throughout the audible spectrum, with the roll-off point positioned well beyond the limits of human hearing. The combination of warmth and beautifully open, unrestricted high frequencies is a signature feature of the mid-1980s Focusrite designs that inspired this preamp.

Additionally, the optional eight-channel analog converter is equipped with high-quality Burr-Brown amplifiers and PCM4220 A-D converter chips, all integrated within Focusrite’s bespoke analog circuitry. Its specifications include a dynamic range of 122dB and jitter performance below 250 picoseconds. This card can be retrofitted at any time and, thanks to the convenient 25-pin D-type connector, it integrates effortlessly with most digital workstations, including Pro Tools.

As a premium addition, users receive the Brainworx bx_console Focusrite SC channel-strip plug-in, an exceptional digital emulation of the iconic and rare Focusrite Studio Console. With only ten of these consoles ever produced, users can now access its legendary sound directly within their DAW.

Additional Features

• ISA series microphone preamps have been the producers’ choice on countless hit records over the last two decades
• 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
• Ideal for microphone matching or extended microphone creativity – settings include the “Vintage ISA110” setting that provides the original Focusrite signature sound
• Instant access on the front fascia – no separate DI box required
• Switchable insert points are featured on every channel, allowing routing (between pre-amp and output) through additional external processing
• Provided on every channel, this is the same filter as featured on the original ISA428
• Clear metering designed to catch even the fastest and most elusive of transients
• Phantom power available on every channel
• Trim control allows 20dB of extra gain with fine adjustment
• Phase reverse buttons help to correct phase issues with microphones or cables
• Optional A-D converters easily synchronize to external word clock
• Includes Brainworx bx_console Focusrite SC channel-strip plug-in, a stellar digital emulation of the legendary and rare Focusrite Studio Console