Focusrite ISA Two Rackmount 2-Channel Microphone Preamp

The Focusrite ISA Two is a dual mono microphone preamplifier that incorporates transformer-based microphone inputs with adjustable input impedance. Drawing inspiration from the renowned designs of the Focusrite Forte and Studio consoles, this preamp delivers up to 80 dB of gain. Additionally, it features two instrument inputs on the front panel, providing convenient access to two transparent direct inputs.

The microphone inputs are equipped with a pair of Lundahl LL1538 transformers featuring a three-section winding design, which minimizes leakage inductance and enhances frequency response. To protect against external magnetic interference, each transformer is housed in mu-metal enclosures. Each channel includes a fully-balanced insert point, which can be activated via a button on the front panel, facilitating the integration of external equalizers, compressors, or limiters.

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Microphone Input Transformer

The Lundahl LL1538 input transformers, selected by Rupert Neve for the ISA 110, are recognized as some of the finest microphone input transformers on the market. The Zobel network integrated into the ISA circuit, refined by Rupert Neve, enables the microphone preamp to achieve an exceptionally flat frequency response over an extensive bandwidth.

Gain

• Offers up to 80 dB of clean, distortion-free gain
  
  
• ISA topology ensures low-noise even at the highest gain levels
  
  
• The transformer supplies 20 dB of gain, while the ISA's input stage offers up to 60 dB of additional gain on the microphone input
  
  

Variable Input Impedance

• Four choices of input impedance, including the original ISA 110 value, allow for matching the preamp to a different microphones, even a vintage type, for the best possible sound
  
  
• Impedance is selected using a switch on the front panel
  
  
• Impedance choice is remembered even when the unit is switched off and back on
  
  

User-Calibrated Metering

• Each channel has an eight-LED array to clearly display the level of the two signals
  
  
• Line up the analog levels with digital converters or a DAW by using the calibration knob on the rear panel
  
  
• Calibration avoids clipping on input
  
  

Instrument and Line Inputs

• Two 1/4" TS connectors on the front panel provide access to a transparent DI input
  
  
• TRS line inputs are available on the rear panel and a front panel switch allows for stepping through them to instantly select required input
  
  

Variable High-Pass Filter

• Smooth-sounding, built-in 18 dB/octave high-pass filter per channel
  
  
• Same design as the original ISA 110 module
  
  
• Ideal for cutting out rumble, thumps and other unwanted low-frequency sounds using the 16 Hz to 420 Hz range
  
  
• Easily accessed with a large knob and illuminated button
  
  

Balanced Inserts

• Each channel has its own balanced insert point via 1/4" TRS send and receive connectors
  
  
• Allows for a choice of signal processor to be connected and switched in and out using the illuminated switch on the front panel
  
  

Focusrite Console Plug-In

Includes Brainworx bx_console Focusrite SC channel-strip plug-in, a stellar digital emulation of the legendary and rare Focusrite Studio Console