The Focusrite ISA ONE is a single-channel preamp featuring the original ISA design, Lundahl LL1538 input transformer, switchable input impedance including classic ISA 110 setting, variable high-pass filter, independent instrument input, and LED peak meter.
The Focusrite ISA ONE gives you one channel of the console preamp designed for George Martin's AIR Studios, with modern performance enhancements. The ISA ONE retains the classic ISA sound, which in part, comes from its Lundahl LL1538 input transformer and custom Zobel network, which imparts a special character to the sound that can't be truly emulated in any other way. Whereas the original ISA input impedance was calculated to suit the microphones of the day, today's model makes one small change, adding three additional input impedances to the classic ISA 110 setting, allowing you to match any microphone, vintage or modern, and access a wide range of sounds. The ISA ONE also features an independent instrument DI, which gives you the flexibility of simultaneous instrument and vocal recording. You can also use the ISA ONE as a DAW front end with zero-latency monitoring with the optional A-D card, offering up to 24-bit/192kHz sampling via ADAT or AES3.
Focusrite ISA ONE - Just the Facts
- Classic ISA mic preamp design featuring Lundahl LL1538 input transformer
- Flexible independent DI channel
- Switchable input impedance including classic ISA 110 setting
- Headphone output with volume control
- Dedicated insert point
- Optional stereo 192kHz A-D conversion card
Bring console-grade warmth and precision to any recording setup with the Focusrite ISA One. This rugged, desktop-style preamp combines classic transformer-based circuitry, versatile impedance switching, and a front-panel instrument input in a compact chassis. Designed around Focusrite’s legendary ISA 110 module, the ISA One delivers up to 80 dB of ultra-clean gain, Tone-shaping “Air” enhancement, and intuitive controls—perfect for vocals, guitars, drum overheads, and line-level sources.
Key Features
-
Transformer-Based Preamplifier – Lundahl LL1538 mic input transformer and custom output transformer for smooth saturation, low noise, and up to 80 dB of gain.
-
Variable Impedance – Four selectable mic-load settings (600 Ω, 1.4 kΩ, 2.4 kΩ, 6.8 kΩ) let you dial in character and response.
-
Air-Mode – Adds high-frequency lift and presence, emulating classic ISA console coloration.
-
Front-Panel DI – High-impedance JFET instrument input runs in parallel with the mic path for direct recording of guitar, bass, and keyboards.
-
Switchable High-Pass Filter – 18 dB/octave filter with cutoff adjustable from 16 Hz to 420 Hz to tame rumble and clean low-end.
-
Phase & Phantom Power – Independent 48 V phantom power and polarity-reverse switches.
-
Pro-Grade Metering – Precision VU meter with adjustable 0 VU calibration (11–26 dBu) and ±20 dB fine-trim control.
Optional Expansion
-
ADN2 A-D Converter Card Slot – Add 24-bit/96 kHz conversion plus AES3, S/PDIF, ADAT, or Dante outputs for seamless digital integration.
What’s Included
Why You’ll Love It
Whether you’re building a portable tracking rig or upgrading your studio’s front end, the ISA One delivers the revered Focusrite console sound in a versatile, all-analog package. Its blend of transformer warmth, precise controls, and optional digital add-on makes it the go-to preamp for any serious engineer or producer.
