Focusrite ISA C8X – a professional audio interface with 26 inputs and 28 outputs over USB-C, housed in a 2U rackmount chassis — and the first interface ever released under the ISA name. The two ISA preamps at its core carry the same Lundahl LL1538 transformer that Rupert Neve selected for the original 1985 ISA 110 commission. Six additional ultra-low-noise Focusrite preamps, RedNet-class 24-bit/192kHz AD/DA conversion, and full remote control via Focusrite Control 2 round out the spec.
Transformer character and all-analogue tone shaping
Both ISA preamps deliver up to 79 dB of gain with switchable input impedance, balanced inserts, and a variable high-pass filter — covering everything from ribbons and passive dynamics to condenser mics without compromise. Two relay-switched analogue modes extend the tonal range: Console Mode introduces variable soft-clipping for saturation and low-end weight, while 430 Air Mode — ported directly from the ISA 430 MkII — lifts the top end through an inductor-based high-shelf filter. Both modes are active on the two front-panel instrument DI inputs as well, which share the full transformer signal path.
A permanent I/O hub, not just an interface
ISA C8X is built for fixed installations and patchbay rigs: dedicated mic and line inputs on all eight channels mean outboard gear stays connected between sessions. Twelve balanced line outputs handle monitoring from mono through to 7.1.4 across three independently switchable monitor groups — controllable from the front panel or the app. ADAT expansion adds up to 16 channels, and Word Clock, S/PDIF, and MIDI complete the connectivity picture. Auto Gain across all eight preamps simultaneously handles multi-mic setups — drums in particular — in seconds. The RedNet-derived converters post 125 dB of dynamic range with 0.00022% THD. Standalone mode keeps audio passing even without a connected computer.
KEY FEATURES
- 2 ISA transformer preamps with Lundahl LL1538, up to 79 dB gain
- 6 Focusrite mic preamps with up to 69 dB gain and analogue Air mode
- Console Mode and 430 Air Mode — fully analogue, relay-switched tone circuits
- Balanced inserts on ISA channels, switchable impedance, variable HPF
- Auto Gain across all 8 preamps simultaneously
- 12 balanced line outputs, 3 monitor groups, up to 7.1.4 support
- 2 headphone outputs with independent level control, 130 mW, 116 dB DR
- 16-channel ADAT I/O, S/PDIF, Word Clock I/O, MIDI I/O
- Full remote control via Focusrite Control 2 (desktop + iOS/Android)
- Standalone mode — operates without a host computer
- Includes Hitmaker Expansion (Brainworx bx_console Focusrite SC, Oxford Reverb, and more)
TECHNICAL SPECIFICATIONS
- Inputs: 26 (8 mic/line XLR-TRS combo, 2 front DI, 16 ADAT, 2 S/PDIF, 2 MIDI)
- Outputs: 28 (12 balanced line, 2 headphone, 16 ADAT, 2 S/PDIF, 2 MIDI)
- Outputs 1–2: simultaneous XLR and TRS, +24 dBu max output level
- Conversion: 24-bit / 192 kHz, up to 125 dB dynamic range (A-weighted), 0.00022% THD
- Gain: ISA channels up to 79 dB, Focusrite channels up to 69 dB
- ISA input impedance: switchable (multiple positions)
- Headphone output: up to 130 mW, 3 Ω output impedance, up to 116 dB DR
- Host connectivity: USB-C
- Clock: Word Clock I/O
- Form factor: 2U rackmount
- Chassis: anodised aluminium
