ISA 428 MkII

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)