ISA C8X
26-in, 28-out USB-C audio interface with eight preamps, including two ISA transformer mic preamps
ISA C8X combines the trademark ISA sound with comprehensive remote control and all the analogue and digital I/O, routing, and recallability you need to run your entire studio, plus switchable impedance, balanced inserts, and high-pass filtering. The first two channels feature ISA preamps with classic Lundahl LL1538 transformers and Console and 430 Air modes for new tonal options. All eight are fully controllable from the front panel and via Focusrite Control 2.
The ISA sound, evolved
The ISA story starts in 1985 with a request from Sir George Martin to Rupert Neve: build a no-compromise mic preamp. That circuit became the foundation of every ISA product made since. 40 years on, it lives in ISA C8X — Focusrite’s first ISA audio interface, housed in anodised aluminium in Focusrite’s original blue colour, with heritage transformer sound in a 26-in, 28-out USB-C interface built for the modern studio.
Heritage sound with total control
The two ISA preamps at the heart of ISA C8X feature the same Lundahl LL1538 transformers Rupert Neve chose in 1985. Warm, rich, and detailed on any source, with up to 79dB of gain, switchable impedance, and balanced inserts — and for the first time in ISA’s storied history, remotely controllable via Focusrite Control 2.
All-analogue tone
ISA gives you two relay-switchable analogue circuits. Console mode introduces warm saturation and low-end punch via a variable soft-clip circuit. 430 Air, lifted directly from the ISA 430 MkII, adds high-end shimmer through an inductor-based high-shelf filter. Both are completely analogue with full-bodied sound.
Key Features
- 2U rack-mounted, 26-in/28-out USB-C audio interface
- Eight remote-controlled preamps with up to 79dB of gain, two of which are ISA preamps with Lundahl LL1538 transformers
- All-analogue Console and 430 Air modes for tonal shaping
- 24-bit/192kHz AD/DA conversion with up to 125dB of dynamic range
- Additional Sonnox bundles available
Specifications
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Hardware Overview
- Microphone Preamps 8
- Phantom Power Yes (Independent per-channel)
- Line Inputs 8
- Instrument Inputs 2
- Insert Sends 2
- Insert Returns 2
- Line Outputs 12
- Headphone Outputs 2
- Line Outputs 10
- Headphone Outputs 2
- ADAT Inputs 2 (16 channels at 44.1/48kHz and up to 8 channels at 96kHz)
- ADAT Outputs 2 (16 channels at 44.1/48kHz and up to 8 channels at 96kHz)
- SPDIF Input 1 (2 channels at 96kHz)
- SPDIF Output 1 (2 channels at 96kHz)
- MIDI Input 1
- MIDI Output 1
- Word Clock Input 1
- Word Clock Output 1
- Talkback Yes
- Loopback Yes
- Connectivity USB Type-C
- Protocol USB 2.0
- Form Factor Rack Mountable (2U)
- Simultaneous I/O 26×28 (including Loopback)
- A/D Resolution 24-bit/192 kHz
- Maximum Power Draw 40W
- Bus Powered N
ISA Microphone Inputs (Channels 1-2)
- Frequency Response 20Hz-20kHz (±0.4dB)
- Dynamic Range (A-weighted) 117dB
- THD+N (minimum at minimum gain) -93dB (0.00023%)
- 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 (HPF) 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) +15dBu
- 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
Line Outputs
- Frequency Response 20Hz-20kHz (±0.02dB)
- Dynamic Range (A-weighted) 125dB
- THD+N (minimum) -113dB (0.00023%)
- Maximum Output Level +24dBu
Headphone Outputs
- Frequency Response 20Hz-20kHz (±0.1dB)
- Dynamic Range 114dB @ 33Ω, 116dB @ 300Ω, 116dB @ 600Ω
- THD+N -102dB @ 33Ω, -110dB @ 300Ω, -110dB @ 600Ω
- Max Output Level +8dBu @ 33Ω, +11dBu @ 300Ω, +11dBu @ 600Ω
- Max Output Power 130mW @ 33Ω, 28mW @ 300Ω, 14mW @ 600Ω
- Output Impedance 3Ω
Compatibility
- Windows Intel, AMD, and Arm64 processors supported
- MacOS Apple Silicon and Intel processors supported
Dimensions
- Width482.6 mm (19.00 in)
- Depth292.8 mm (11.53 in)
- Height 89 mm (3.50 in)
- Weight 5.558 kg (12.26 lbs)
Power Requirements
- External40W
What’s in the Box?
- ISA C8X audio interface
- 1.5mm USB type C-to-C cable
- Region-specific IEC cable
- Rubber feet (x4)
3 year Warranty