Focusrite ISA Two – Dual-Channel Transformer-Based Mic Preamp with Variable Impedance & Instrument Inputs
The Focusrite ISA Two delivers two channels of legendary analog tone in a premium 1U rackmount format. Based on the iconic ISA 110 preamp design by Rupert Neve, and featuring Lundahl LL1538 input transformers, this preamp is ideal for engineers, producers, and artists looking for transparent, musical recordings with depth and character.
Each channel includes selectable mic, line, or instrument inputs, with front-panel access for instruments and dedicated TRS sockets for line-level sources. The signature switchable input impedance, including the classic ISA 110 setting, ensures optimal performance with any microphone, whether vintage or modern.
With a massive gain range of up to 80dB, precision variable high-pass filter (16Hz–420Hz), and rear-panel insert points, the ISA Two is ideal for clean vocal takes, capturing delicate acoustic instruments, or running through external compressors and EQs. The 8-segment LED peak meters with user-calibration offer clear and accurate level monitoring, making this unit perfect for integration into hybrid analog/digital studios.
All housed in a road-ready rack unit and covered by Focusrite’s 3-year warranty, the ISA Two is a serious tool for discerning audio professionals who want world-class preamps without compromise.
At-a-Glance Highlights
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Dual-channel classic Focusrite ISA mic preamps
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Features Lundahl LL1538 transformers for sonic depth
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Mic, line, and instrument inputs per channel
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Front-panel instrument input for easy access
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Switchable impedance with ISA 110 setting for mic matching
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High-pass filter (16Hz–420Hz) with 18dB/oct roll-off
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Rear insert points for inline analog processors
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User-calibrated 8-segment LED meters for accurate gain staging
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Built for rackmount studio integration
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3-Year Warranty included for long-term reliability
Mic Input Response
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Gain Range: 0 dB to 60 dB in 10 dB steps, plus 0 dB to 20 dB continuous trim
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EIN: -127 dB
(Measured at 60 dB gain with 150 Ω source impedance, 22 Hz–22 kHz bandpass filter)
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Noise (Unity Gain): -97 dBu
(Measured with 22 Hz–22 kHz bandpass filter)
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Frequency Response:
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At minimum gain (0 dB): -0.5 dB at 10 Hz, -1 dB at 135 kHz (relative to 1 kHz)
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At 60 dB gain: -6 dB at 10 Hz, -1 dB at 115 kHz (relative to 1 kHz)
Line Input Response
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Gain Range: -20 dB to 10 dB in 10 dB steps, plus 0 dB to 20 dB continuous trim
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Input Impedance: 10 kΩ (from 10 Hz to 200 kHz)
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Frequency Response:
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At minimum gain (0 dB): -0.3 dB at 10 Hz, -1 dB at 80 kHz (relative to 1 kHz)
High-Pass Filter
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Roll-off: 18 dB/octave (3-pole filter)
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Frequency Range: Continuously variable from 16 Hz to 420 Hz (-3 dB point)
