FOCUSRITE ISA C8x | 26 In / 28 Out Usb-c Audio Interface

ISA C8X

26x28 USB-C Audio Interface

The Focusrite ISA C8X is a 26x28 USB-C audio interface featuring two Lundahl transformer-equipped ISA mic inputs, six remote-controllable Focusrite mic pres, and up to 79 dB of gain. With saturation and air via the Console and 430 Air modes, analog tone is a button press away.

The front panel features colorful LED meters for the mic pres and two independent headphone outputs. ISA mic pre gain control includes both stepped and fine gain control. Two 1/4" Hi-Z instrument inputs feature selectable impedance (also available on mic inputs) and are passed through the same Lundahl LL1538 input transformers and ISA circuitry as the mics. AD/DA conversion is via RedNet 24-bit / 192 kHz converters. Mic inputs feature selectable mic or line input, 48V phantom power, high-pass filter, and analog drive or air.

Along with the eight XLR mic inputs, the interface sports eight balanced 1/4" TRS line inputs, 12 balanced line outputs (supporting up to 7.1.4 speaker setups), and stereo send and return connectivity. Digital connections include 16 channels of ADAT I/O via TOSLINK, S/PDIF I/O via 3.5mm, BNC wordclock I/O, and MIDI I/O over 5-pin DIN connectors. With convenient remote control through the Focusrite Control 2 apps, you can easily control all functions and engage convenient features like automatic gain across all mic preamps for a speedy workflow.

Classic Preamps, Digital Control

C8X's two ISA preamps each feature Lundahl LL1538 input transformers that add subtle warmth and body to any signal, plus balanced inserts, stepped and fine gain control, switchable impedance, high-pass filter, and up to 79 dB of gain—all digitally controlled via the Focusrite Control 2 app. 

• Lundahl LL1538 transformer
• Stepped and fine-gain control
• 430 Air from the ISA 430 MkI
• Impedance switching from the modern ISA range
• High-pass filter from ISA One
• Balanced inserts
• Brand-new all-analog Console mode
• 79 dB of gain

What is ISA?

Forty years ago, Rupert Neve set out to create the finest channel strips ever made for Sir George Martin’s AIR Studios in Montserrat. The result was the legendary ISA 110 module, marking the birth of the Focusrite name.

The ISA 110 preamp became known for its ultralow-noise, ultralow-distortion design, combining the best components and design principles available at the time to capture every detail of the artist’s sound. The ISA range has been a constant throughout Focusrite’s history, and each generation of hardware has built and expanded on features of the previous while remaining true to the core of Neve’s design..

Console Mode

ISA C8X is an all-analog design by default, delivering pristine signal at low levels. When you enable Console mode, you introduce new character—subtle saturation that increases as you drive the channel harder.

This brand-new analog circuit adds warmth and low-end punch, giving you the feel of a classic console without compromising clarity. Exaggerate or dial back the effect with fully variable controls.

430 Air Mode

The 430 Air circuit (lifted from the eponymous ISA 430 MkII) adds high-end detail via an inductor-based high-shelf filter. Console and 430 Air, when added to the rich and nuanced sound from the Lundahl LL1538 transformer at the front end and shaped by the impedance and high-pass filter controls, combine to form the best-sounding and most flexible analog signal path Focusrite have ever put in an audio interface.

Front-Panel, Transformer-Based Instrument Inputs

Inspired by the ISA One's well-regarded DI channel, the front-panel instrument inputs feature selectable impedances for preserving the natural tone of guitar, bass, and other instruments. These also run through the ISA transformer circuitry, allowing you to apply both Console and 430 Air modes.

Six Remote Controllable, Ultralow-Noise Mic Pres

Alongside the two ISA preamps are six remote-controllable, ultralow-noise Focusrite mic preamps. Each one is designed to reliably capture every nuance with 69 dB of clear, detailed gain, and includes both analog Air processing for high-end clarity and variable Drive DSP for analog-style harmonic saturation.

Eight Dedicated Balanced Line inputs

Designed for patchbay setups and permanent installations, ISA C8X provides fixed line inputs that let you connect your outboard gear once and avoid repatching. With a direct path to the ADC, all line inputs bypass the preamp entirely, delivering maximum headroom and the cleanest and shortest signal route possible. Ideal for setups where transparency and efficiency are key.

12 Balanced Line Outputs

Work in mono, stereo, or up to 7.1.4 with up to three monitor groups and front-panel or remote switching. Output levels match line-input levels, and outputs 1 and 2 are available on both XLR and 1/4" TRS. All outputs include anti-thump speaker protection.

Flagship AD/DA Conversion

Whichever inputs you choose, you'll be recording and mixing with the same 24-bit / 192 kHz AD/DA converters used in Focusrite's RedNet range, offering 125 dB of dynamic range and ultralow distortion at 0.00022% THD. And C8X's two headphone outputs each offer independent level control, extra headroom, and optimized impedance for powerful, detailed playback.

Remote Control Recording

Focusrite Control 2 is designed for both desktop and mobile devices, making it easy to manage gain levels, route audio, save and recall preset mixes, and monitor with low latency, wherever you install ISA C8X in your studio. It also supports control of multiple connected interfaces simultaneously, so when expanding your setup via ADAT with other Focusrite Control 2–ready devices, you can switch between them and control each one directly from the app.

Specifications

• Display
  • 3x Color Multi-Segment LED Meter
• Maximum Sampling Rate
  • 192 kHz / 24-Bit
• Number of Microphone Inputs
  • 8
• Input Level Adjustment
  • 6x Knob
  • Automatic
• Gain/Trim Range
  • Mic Inputs: Up to 79 dB
  • Mic/Line Inputs: Up to 69 dB
• High-Pass Filter
  • 75 Hz, 18 dB/Octave
• Analog Audio I/O
  • 8x XLR 3-Pin Balanced Mic Input
  • 8x 1/4" TRS Balanced Line Input
  • 2x 1/4" TS Unbalanced Hi-Z Input
  • 2x XLR 3-Pin Balanced Line/Main Output
  • 12x 1/4" TRS Balanced Line Output
  • 2x 1/4" TRS Headphone Output
  • 2x 1/4" TRS Insert Send
  • 2x 1/4" TRS Insert Return
• Phantom Power
  • 48 V, Selectable On/Off (Selectable on Individual Inputs)
• Digital Audio I/O
  • 2x TOSLINK Optical ADAT Input
  • 1x 1/8" / 3.5 mm Coaxial S/PDIF Input
  • 2x TOSLINK Optical ADAT Output
  • 1x 1/8" / 3.5 mm Coaxial S/PDIF Output
• Host Connection / USB
  • 1x USB-C
• Host Connection Protocol
  • USB 2.0
• Sync I/O
  • 1x BNC Word Clock Input
  • 1x BNC Word Clock Output
• MIDI I/O
  • 1x DIN 5-Pin Input
  • 1x DIN 5-Pin Output
• Frequency Response
  • 20 Hz to 20 kHz
• Maximum Input Level
  • Mic/Insert Inputs: +16 dBu
  • Line Inputs: +24 dBu
  • Hi-Z: +14 dBu
• Maximum Output Level
  • Line Outputs: +24 dBu
  • Headphone Outputs: +11 dBu (at 600 Ohms)
• Headphone Output Power
  • 130 mW per Channel into 33 Ohms
  • 14 mW per Channel into 600 Ohms
• Impedance
  • Mic Inputs: 800 to 7000 Ohms
  • Hi-Z Inputs: 400 Kilohms 1.2 Megohms
  • Headphone Outputs: 3 Ohms
• Dynamic Range
  • Hi-Z Inputs: 117 dBA
  • Line Inputs: 120 dBA
  • Mic Inputs: 117 dBA (ISA Mic Inputs) 116 dBA (Normal Mic Inputs)
  • Headphone Outputs: 114 dB (at 33 Ohms) 116 dB (at 600 Ohms)
  • Line Outputs: 125 dBA
• THD+N
  • Mic Inputs: -93 dB / 0.0023% (ISA Mic Pres) -100 dB / 0.001%
  • Line Inputs: < -105 dB / 0.00056% 
  • Hi-Z Inputs: -89 dB / 0.0036%
  • Line Outputs: -113 dB / 0.00023%
  • Headphone Outputs: -102 dB (at 33 Ohms) -110 dB (at 600 Ohms)
• EIN
  • Mic Inputs: -128 dB A-Weighted (ISA Mic Pres) -127 dB A-Weighted
• Sample Rates
  • Up to 192 kHz
• Bit Depths
  • 24-Bit
• Sync Sources
  • MIDI Time Code (MTC), Word Clock
• Clocking
  • Internal
• OS Compatibility
  • macOS / Windows
• Required Hardware
  • USB-C Port
• Power Requirements
  • AC Input
• AC Input Power
  • Universal: 100 to 240 VAC, 50 / 60 Hz
• Power Consumption
  • 40 W (Maximum)
• Rackmount Size
  • 2 U
• Dimensions
  • 19" / 48.3 cm

In The Box

• Focusrite ISA C8X 26x28 USB-C Audio Interface
• Power Cable
• Limited 3-Year Manufacturer Warranty