Focusrite

Focusrite AMS-ISA-2 Dual Mono Mic Preamp - Transformer-Based

4.7 (75 reviews)
4in

Sculpt Your Sound with Classic Focusrite Preamps The Focusrite ISA Two is a classic dual-mono microphone preamplifier, renowned for its pristine sound and versatile features. Featuring transformer-based circuitry and variable impedance settings, it allows you to capture the true essence of your ...

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*Price sourced from Amazon.com. Last updated:Jun 27, 2026.Price and availability are subject to change.

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Overview

Sculpt Your Sound with Classic Focusrite Preamps

The Focusrite ISA Two is a classic dual-mono microphone preamplifier, renowned for its pristine sound and versatile features. Featuring transformer-based circuitry and variable impedance settings, it allows you to capture the true essence of your recordings with exceptional clarity and warmth.

  • Preamplifier Type: Dual Mono Microphone Preamplifier
  • Transformer: Lundahl LL1538 mic input transformer
  • Gain: Up to 80 dB maximum gain on the microphone input
  • Input Impedance: Variable input impedance with four choices
  • Metering: User-calibrated eight-LED array per channel
  • DI Input: Two 1/4in. jack sockets on the front panel
  • High-Pass Filter: Variable cut-off 18dB/octave high-pass filter
  • Inserts: Rear panel balanced inserts with 1/4in. TRS send and receive connections

Key Features

Lundahl LL1538 mic input transformer: Rupert Neve originally chose the Lundahl LL1538 to be the input transformer on the ISA 110. It remains the best microphone input transformer available, and is used in every ISA Series mic pre

The much-heralded ISA topology also ensures low noise, even at the highest gain levels. The transformer supplies 20 dB of gain, while ISA's input stage offers up to 60 dB in addition, giving a total of up to 80 dB of maximum gain on the microphone input

Variable input impedance: Four choices of input impedance, including the original ISA 100 value, allow you to match the preamp to your microphone, even if it's a vintage type, giving you the best possible sound

User-calibrated metering: Each channel has an eight-LED array to clearly display the level of your two signals. Line up your ISA Two levels to match your DAW converters with the calibration knob on the rear panel

Two 1/4in. jack sockets on the front panel of ISA Two give you instant access to a transparent DI input. TRS line inputs are available on the rear panel too, and you can step through them instantly to select the one you want

Variable cut-off high-pass filter: Built in, and easily accessed with its own large knob and illuminated button, is an extremely smooth sounding 18dB/octave high-pass filter of the same design as the original ISA 110 module

Rear panel balanced inserts: Each channel of ISA Two has its own balanced insert point. With 1/4in. TRS send and receive connections, your choice of signal processor can be connected and switched in and out using the illuminated switch on the front panel

Specifications

Model
AMS-ISA-2
Type
Dual Mono Mic Preamp
Input Transformer
Lundahl LL1538
Max Microphone Gain
80 dB
Input Impedance Options
4 (including original ISA 100)
High-Pass Filter
18dB/octave, ISA 110 design
DI Inputs
2 x 1/4" Jack Sockets (Front Panel)
Line Inputs
TRS (Rear Panel)
Metering
8-LED Array (User-Calibrated)
Inserts
Balanced 1/4" TRS (Rear Panel)
Brand
Focusrite

Pros & Cons

👍 Pros

  • Incorporates the revered Lundahl LL1538 mic input transformer, chosen by Rupert Neve for its superior quality
  • Offers extremely low noise performance, even when operating at the highest gain levels, ensuring pristine recordings
  • Provides up to 80 dB of maximum gain on the microphone input, accommodating a wide range of microphones
  • Features four choices of input impedance, including the original ISA 100 value, for optimal microphone matching
  • Includes an extremely smooth sounding 18dB/octave high-pass filter, identical in design to the original ISA 110 module
  • Equipped with two 1/4in. jack sockets on the front panel for instant access to a transparent DI input
  • Each channel features user-calibrated metering with an eight-LED array to precisely display signal levels
  • Offers rear panel balanced inserts with 1/4in. TRS send and receive connections for integrating external processors

👎 Cons

  • The specific advantages of the various input impedance settings are not detailed, requiring user experimentation
  • While offering ample gain, the noise floor at specific high gain settings is not quantified for objective comparison
  • Requires external signal processors for the balanced inserts, as none are built into the unit
  • The benefits of the "original ISA 110 module" filter design are stated qualitatively without explicit technical details
  • The unit's functionality, while extensive, might present a learning curve for those unfamiliar with advanced preamps

Frequently Asked Questions

The Focusrite ISA Two utilizes the Lundahl LL1538 mic input transformer, originally chosen by Rupert Neve for its exceptional quality in the ISA 110.
The ISA Two offers up to 80 dB of maximum gain on the microphone input, making it suitable for a wide range of microphones, including low-output models.
Yes, the Focusrite ISA Two provides four choices of input impedance, including the original ISA 100 value, allowing you to optimize the preamp for your specific microphone.
Yes, it features a built-in, extremely smooth sounding 18dB/octave high-pass filter, designed similarly to the original ISA 110 module, accessible with its own large knob.
Yes, the front panel of the ISA Two includes two 1/4in. jack sockets that provide instant access to a transparent DI input for instruments.