Focusrite ISA C8X USB-C Audio Interface With ISA Preamps

The Focusrite ISA C8X is a flagship 2U USB-C audio interface that brings classic ISA transformer preamps and RedNet-grade conversion into a single, studio-command centre. With eight remote-controllable mic pres, flexible analogue and digital I/O, and deep software integration via Focusrite Control 2, it is designed to handle everything from writing sessions and overdubs to full-band tracking and immersive mixing, all with the unmistakable ISA sound.

Classic ISA Sound, Modern Control

At the heart of ISA C8X are two Lundahl transformer-based ISA microphone preamps, delivering the subtle warmth, weight and musicality that have made ISA a studio staple for decades. Each preamp offers up to 79dB of gain, switchable impedance, high-pass filtering and balanced inserts, so you can tailor the front end precisely to your microphones and outboard. Crucially, every setting can be controlled and recalled from the front panel or via Focusrite Control 2, giving you the feel of a large-format console with the convenience of digital recall.

All-Analogue Console and 430 Air Modes

ISA C8X gives you instant access to two powerful tonal options on the ISA channels. Console mode introduces variable analogue saturation and low-end punch using a soft-clip circuit that can be dialled in to taste, while 430 Air mode, derived from the ISA 430 MkII, adds an inductor-based high-shelf lift for extra clarity and sheen. Both modes are fully analogue but controlled digitally, so you can experiment freely, save your favourite settings and recall them in seconds.

Eight Preamps for Any Session

Alongside the two ISA channels, ISA C8X includes six ultra-low-noise mic preamps with up to 69dB of clean, detailed gain. These are designed to capture every nuance of vocals, drums, acoustic instruments and more, with Air mode available for added presence and Drive DSP for analogue-style harmonic warmth. Two front-panel instrument inputs, inspired by the ISA One DI, run through the Lundahl transformers with selectable impedance, Console and 430 Air modes, giving guitars and basses a familiar, amp-like feel straight into your DAW.

Flagship Conversion and Flexible Monitoring

With the same 24-bit/192kHz AD/DA converters found in Focusrite’s RedNet range, ISA C8X delivers up to 125dB of dynamic range and ultra-low distortion, so every source is captured and played back with precision. Twelve balanced line outputs support mono, stereo and immersive formats up to 7.1.4, with three monitor groups and front-panel or remote switching for flexible control-room setups. Two class AB headphone outputs with independent level control and optimised impedance ensure powerful, detailed cue mixes for artists and engineers alike.

Built to Run Your Studio

ISA C8X is designed to live at the heart of a permanent rig. Eight dedicated fixed-gain balanced line inputs make it easy to integrate patchbays and outboard without constant re-patching, while ADAT, S/PDIF, MIDI and Word Clock connectivity allow you to expand and sync larger systems. Auto Gain can set levels across all eight preamps in seconds, and Focusrite Control 2 for desktop and mobile lets you manage routing, gain, monitoring and presets remotely, even when ISA C8X is racked away from your mix position.

• Two Lundahl Transformer-Based ISA Preamps - Capture vocals and instruments with the classic ISA character, using Lundahl LL1538 input transformers, up to 79dB of gain, switchable impedance, high-pass filters and balanced inserts, all with digitally controlled recall for fast, repeatable setups.
• Six Ultra-Low-Noise Remote Mic Preamps - Expand your front end with six additional mic pres offering 69dB of clean gain, Air mode for added presence and Drive DSP for analogue-style warmth, ideal for drums, ensembles and multi-mic sessions.
• Flagship 24-bit/192kHz Conversion - Record and mix with the same converters used in Focusrite RedNet, delivering up to 125dB of dynamic range and ultra-low distortion so your microphones, instruments and outboard are heard exactly as intended.
• 26x28 USB-C Interface with Flexible I/O - Run your entire studio from one 2U rack unit, with eight mic pres, eight fixed line inputs, 12 balanced line outputs, dual headphone outs, ADAT, S/PDIF, MIDI and Word Clock, plus comprehensive routing and monitoring via Focusrite Control 2.

General

• Product: Focusrite ISA C8X USB-C Audio Interface
• Form Factor: Rack mountable (2U)
• Simultaneous I/O: 26 inputs x 28 outputs (including Loopback)
• Connectivity: USB Type-C
• Protocol: USB 2.0
• A/D Resolution: 24-bit / 192kHz
• Maximum Power Draw: 40W
• Bus Powered: No

Analogue Inputs

• Microphone Preamps: 8 (Channels 1-8)
• Phantom Power: Yes (independent per channel)
• Line Inputs: 8 fixed-level (Channels 1-8)
• Instrument Inputs: 2 (front panel, transformer-based, Channels 1-2)
• Insert Sends: 2 (Channels 1-2)
• Insert Returns: 2 (Channels 1-2)
• Talkback: Yes
• Loopback: Yes

ISA Microphone Inputs (Channels 1-2)

• Frequency Response: 20Hz-20kHz (±0.4dB)
• Dynamic Range (A-weighted): 117dB
• THD+N (minimum at minimum gain): -93dB (0.0023%)
• Noise EIN (A-weighted): -128dB
• Maximum Input Level (minimum gain, Low impedance): +16dBu
• Gain Range: 79dB
• Input Impedance (switchable): 800Ω (Low), 1400Ω (ISA 110), 2400Ω (Med), 7000Ω (High)
• High-Pass Filter: 75Hz cut-off frequency, 18dB/octave

Microphone Inputs (Channels 3-8)

• Frequency Response: 20Hz-20kHz (±0.1dB)
• Dynamic Range (A-weighted): 116dB
• THD+N (minimum at 8dB gain): -100dB (0.001%)
• Noise EIN (A-weighted): -127dB
• Maximum Input Level (minimum gain): +16dBu
• Gain Range: 69dB
• Input Impedance: 3200Ω

Fixed-Level Line Inputs (Channels 1-8)

• Frequency Response: 20Hz-20kHz (±0.05dB)
• Dynamic Range (A-weighted): 120dB
• THD+N (minimum): < -105dB (0.00056%)
• Maximum Input Level: +24dBu

Instrument Inputs (Channels 1-2)

• Frequency Response: 20Hz-20kHz (±0.5dB)
• Dynamic Range (A-weighted): 117dB
• THD+N (minimum): -89dB (0.0036%)
• Maximum Input Level (at minimum gain): +14dBu
• Gain Range: 79dB
• Input Impedance (switchable): 400kΩ (Low), 1.2MΩ (High)

Inserts (Channels 1-2)

• Connection: Balanced
• Maximum Output Level (send): +16dBu
• Maximum Input Level (return): +16dBu

Analogue Outputs

• Line Outputs: 12 balanced (10 line outputs plus monitor outputs 1-2 on XLR and TRS)
• Frequency Response: 20Hz-20kHz (±0.02dB)
• Dynamic Range (A-weighted): 125dB
• THD+N (minimum): -113dB (0.00023%)
• Maximum Output Level: +24dBu
• Headphone Outputs: 2 (class AB, independent level control)

Headphone Outputs

• Frequency Response: 20Hz-20kHz (±0.1dB)
• Dynamic Range: 114dB @ 33Ω, 116dB @ 300Ω, 116dB @ 600Ω
• THD+N: -102dB @ 33Ω, -110dB @ 300Ω, -110dB @ 600Ω
• Maximum Output Level: +8dBu @ 33Ω, +11dBu @ 300Ω, +11dBu @ 600Ω
• Maximum Output Power: 130mW @ 33Ω, 28mW @ 300Ω, 14mW @ 600Ω
• Output Impedance: 3Ω

Digital I/O

• ADAT Inputs: 2 (up to 16 channels at 44.1/48kHz, up to 8 channels at 96kHz)
• ADAT Outputs: 2 (up to 16 channels at 44.1/48kHz, up to 8 channels at 96kHz)
• S/PDIF Input: 1 (2 channels at up to 96kHz)
• S/PDIF Output: 1 (2 channels at up to 96kHz)
• MIDI Input: 1
• MIDI Output: 1
• Word Clock Input: 1
• Word Clock Output: 1

Software & Control

• Control Software: Focusrite Control 2 (desktop and mobile)
• Auto Gain: Available across all eight preamps
• Remote Control: Gain, routing, monitoring and preset recall via Focusrite Control 2

Compatibility

• Windows: Intel, AMD and Arm64 processors supported
• macOS: Apple Silicon and Intel processors supported
• Linux: UAC2 class compliant (operation not tested or supported)