Dream Big with Focusrite - Win a dream recording weekend at Air Studios. Click here to enter

ISA 428 MkII

ISA 428 MkII
Four classic preamps with DI inputs and a premium eight-channel A-D converter option

Specifications

We always quote 'real world' performance figures (measured to the AES17 standard). Some companies choose to quote chipset performance, which is misleading, and here's why.

Mic Inputs

  • Frequency response at minimum gain (0dB): -0.35dB at 20Hz and –3dB at 122kHz
  • Frequency response at maximum gain (60dB): –2.5dB at 20Hz and –3dB 103kHz
  • Gain range: 0dB to +60dB in 10dB steps, plus 0dB to +20dB continuously variable trim
  • Maximum headroom: +7.4dBu
  • THD+N: 0.0009% (measured at 1kHz -20dBu input signal, at 30dB gain setting, with a 20Hz/22kHz bandpass filter)
  • Noise EIN: -126dB (measured at 60dB of gain with 150Ω termination and 20Hz/22kHz bandpass filter)
  • Noise at main output with unity gain: -98dBu (measured with a 20Hz/22kHz bandpass filter)
  • SNR: 123dB (relative to max output 25dBu)
  • SNR: 120dB (relative to 0dBFS (+22dBu)
  • CMRR: 88dB. 
  • Input Impedance, variable: 600Ω, 1400Ω, 2400Ω, 6800Ω

Line Inputs

  • Frequency Response at unity gain (0dB): -0.3dB at 20Hz and –3dB at 94kHz
  • Gain range: -20dB to +10dB in 10dB steps, plus 0dB to +20dB continuously variable trim
  • Maximum headroom: +25.4dBu
  • THD+N: 0.002% (measured with +4dBu input signal, 0dB gain setting, with a 20Hz/22kHz bandpass filter)
  • Noise at main output with unity gain: -91dBu (measured with a 20Hz/22kHz bandpass filter)
  • SNR: 116dB (relative to max output 25dBu)
  • SNR: 113dB (relative to 0dBFS +22dBu). Input Impedance: 10kΩ

Instrument Inputs

  • Frequency Response at +10dB gain: -0.2dB at 20Hz and 0dB at 200kHz
  • Frequency Response at +40dB gain: -3dB at 20Hz and –3dB at 38.4kHz
  • Gain range: +10dB to +40dB continuously variable
  • Maximum headroom: +11.5dBu
  • THD+N: 0.006% (measured with –20dBu input signal, at minimum gain (+10dB), with a 20Hz/22kHz bandpass filter)
  • Noise at main output with minimum gain (+10dB): -95dBu (measured with a 20Hz/22kHz bandpass filter)
  • Input Impedance = >1MΩ

High Pass Filter

  • Roll off = 18dB per octave 3 pole filter
  • Frequency range: 16Hz to 420Hz (continuously variable, measured at the 3dB down point)

Meters

6 LED meter is calibrated 0dBFS = +22dBu (the maximum level which can be correctly converted by the optional internal A/D converter before overload occurs). The meter calibration points are as follows:

  • Meter panel calibration value in dBFS / Equivalent dBu value
  • 0dBFS / +22dBu
  • -2dBFS / +20dBu
  • -6dBFS / +16dBu
  • -12dBFS / +10dBu
  • -18dBFS / +4dBu
  • -42dBFS / -20dBu

Front and rear connectivity

Analogue Channel Inputs (Inputs 1-4)

  • 4 instrument 1⁄4” TS jack inputs on front panel 
  • 4 microphone XLR inputs on rear panel 
  • 4 line 1⁄4” TRS jacks on rear panel 
  • 4 insert return 1⁄4” TRS jacks on rear panel
  • 4 ADC XLR inputs on rear panel

Analogue Audio Outputs (Outputs 1-4)

  • 4 line XLR outputs on rear panel 
  • 4 insert send 1⁄4” TRS jacks on rear panel

Other I/O

  • IEC power input connector 100Vac – 240Vac

Front Panel Indicators

  • 8 output meters, 6 segment 
  • 4 30-60 mic gain range selection indicator 
  • 4 +48V phantom power indicator 
  • 4 Phase indicator 
  • 4 Insert In indicator 
  • 4 Filter In indicator 
  • 4 Input selection indicators (Mic, Line, Inst) 
  • 4 Z In microphone input impedance selection indicators (Low, ISA110, Med, High) Clock select indicators (44.1, 48, 88.2, 96, 176.4, 192) 
  • Ext clock indicators (Lock, Word clock, 256X)

Weight

  • 5.5kg
  • 12.2lbs

Dimensions (W x H x D)

  • 480mm (W) x 88mm (H) x 280mm (D)
  • 19" (W) x 3.5" (H) x 11" (D)