Focusrite ISA 428 Pre-Amp mk2


  • Four ISA-series transformer-based pre-amps
    The benefits of Focusrite’s classic pre-amp topology include superb common-mode rejection, an excellent overload margin, an extremely low noise floor and super-wide bandwidth.
  • Dedicated analogue insert points
    Switchable insert points are also featured on every channel, allowing routing (between pre-amp and output) to additional external processing.
  • Accurate ‘moving coil’ peak meters
    Clear metering designed to catch even the fastest and most elusive of transients.
  • Four front panel instrument inputs
    Instant access on the front fascia and no separate DI box required.
  • Eight line inputs
    Four additional A-D converter inputs combine with the four pre-amp inputs to provide eight line inputs, routable discretely to the eight-channel A-D converter option.
  • Eight Channel optional 192kHz A/D conversion card
    With the additional four ADC inputs, two ISA428’s can be used with a single ADC, providing eight channels of pre-amplification, A-D conversion and VU metering.
  • Custom Global A-D converter ‘soft clip’ limiter
    Focusrite’s custom optical design protects the A-D converter by preventing ‘digital overload’. It requires that an A-D converter be installed.
  • Switchable Impedance
    Ideal for mic matching or extended microphone creativity. Settings include the ‘Vintage ISA110’ setting, providing the original Focusrite signature sound.
  • Variable Focusrite high pass filter
    Provided on every channel, this is the same filter as featured on the original ISA110 and the Focusrite forte console.
  • Specifications

    • Transformer-based ISA design
    • Gain range: Line = +/- 18dB, Mic = 0 to 60dB (both in 6dB steps), Inst = +10 to +40 dB variable
    • Input impedance: Line = 10k ohm, Mic = Variable - 600, 2k4 and 6k8 ohm + original ISA 110 settings, Inst = >1M ohm

    Analogue Performance
    • Noise: Line = -96dB, Mic = -128dB (EIN with 150 ohm input resistance at 60dB of gain)
    • THD: Line = 0.003% with 0dBu, 1kHz input and 20Hz to 22kHz band-pass filter, Mic = 0.003%

    Analogue Input and Output connectors (balanced)
    • D.I inputs: 1/4 inch Jack (unbalanced)
    • Mic inputs: XLR (balanced)
    • Line: TRS Jack (balanced)
    • Insert Sends and Returns: TRS Jack (balanced)
    • Additional ADC inputs: XLR (balanced) Line level
    • Analogue Outputs: XLR (balanced)

    Digital Output Option
    • AES/EBU and S/PDIF dual 9-pin D-types
    • Optical - ADAT Lightpipe
    • Bit depths 16-, 20- or 24-bit
    • Frequency options 44.1, 48, 88.2, 96, 176.4 and 192kHz
    • Clock options Standard or ?256 x?
    • Meter - 0 dBFS = +22dBu
    • Digital Performance
    • SNR - 120dB A-weighted

    • 7.36kg
    • 16.2Ibs

    • 484mm (W) x 85mm (H) x 250mm (D)
    • 19" (W) x 3.5" (H) x 9.8" (D)