The Focusrite ISA sound, further developed
Focusrite ISA C8X !
The story of ISA began in 1985 with a request from Sir George Martin to Rupert Neve: build a microphone preamplifier without compromise. That circuit formed the basis for every ISA product made since. 40 years later, it lives on in the ISA C8X – Focusrite’s first ISA audio interface, housed in anodized aluminum in Focusrite’s original blue color, with the traditional transformer sound in a 26-in, 28-out USB-C interface built for the modern studio.
Heritage sound with full control
The two ISA preamplifiers at the heart of the Focusrite ISA C8X feature the same Lundahl LL1538 transformers that Rupert Neve chose in 1985. Warm, rich and detailed at every source, with up to 79 dB of gain, switchable impedance and balanced inserts – and, for the first time in ISA’s illustrious history, remotely controllable via Focusrite Control 2.
The ISA gives you two analog circuits that can be switched via relays. The Console mode provides warm saturation and power in the low range via a variable soft-clip circuit. The 430 Air, taken directly from the ISA 430 MkII, adds a sparkling high via a coil-based high-shelf filter. Both are fully analog and deliver a full-sounding sound.
Specifications ISA C8X
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
- Linux ISA C8X is UAC2 class compliant and should work on most Linux systems but this is not tested or 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)
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