The ISA TWO model has the same typology as the original ISA 110 module, so here we find the Lundahl L1538 transformer and zebel cells. The pair of channels is equipped with inputs for microphone, line and instrument signals.
One of the few changes compared to the original is the addition of a circuit for input impedance selection. ISA TWO can handle four different input impedances: 600ohm, 1400Ohm (same as the original ISA110), 2400Ohm and 6800Ohm. Switching impedances brings two positives: the possibility to match the impedance of the microphone and the preamplifier, but at the same time the possibility to deliberately set a different impedance, which can have a favorable effect on the color of the sound. Of course, the impedance is set for each channel separately.
Focusrite ISA TWO also offers standard preamplifier functions on each channel: phantom power, phase reversal and a high-pass filter with an adjustable cut-off frequency (16-420 Hz). On the front panel we also find an LED level indicator for each channel.
For further frequency and dynamic adjustment, it is possible to use a switchable effect loop (insert) with symmetrically connected TRS connectors.
Properties:
• High-end 2-channel microphone preamplifier
• Typology based on the legendary ISA110 module from the Forte console
• Lundahl L1538 transformer
• Zobel's articles
• Switchable impedance (600ohm, 1400Ohm, 2400Ohm and 6800Ohm)
• Instrument (high impedance) input
• Switchable input (Send / Return)
• LED level indication
• +48 V phantom power supply
• Phase reversal
• High-pass filter (16-420 Hz, 18dB per octave)
• Gain range: up to 80 dB (60dB after 10dB steps + 20dB Trim)

Technical specifications :
• Frequency range: 10Hz-80kHz (line input, -3 dB), 10-135kHz (microphone input, -3 dB)
• THD + N : < 0.0007%
• Signal-to-noise ratio: 121dB
• Equivalent noise ( EIN ): > 127dB
• Inputs: 2x XLR (microphone), 2x ¼" Jack TRS (line), 2x ¼" Jack (instrument on the front), 2x ¼" Jack TRS (return)
• Outputs: 2x XLR, 2x ¼" Jack TRS (send)
• Power supply: 220 - 240V
• Weight: 3.7 kg
• 1U rack