FOCUSRITE ISA428 Mkii | 4-channel Mic Preamplifier

ISA 428 MkII

Four Classic Mic Pres

ISA 428 MkII incorporates four of Focusrite's renowned mic pres in a simple-to-operate 2U enclosure, placing four mic preamps, instrument inputs and line ins at your fingertips. The original Focusrite mic pre was designed to suit the microphones of the time; today's model makes one small change, adding three additional input impedances to the classic ISA 110 setting, allowing you to match any microphone, old or new, and access a wide range of sounds, from the character and warmth of a vintage mic to the clear transparency of a modern design.

Each mic pre has the option of mic, line or the front-panel instrument input, with variable input impedance to ensure you are getting the best performance from the source. Up to 60dB of gain is available on the four-position rotary and gain range switches, with a further +20dB of continuously variable trim, meaning a huge 80dB of gain is available should it be required. The high-pass filter features variable cut-off frequency between 16 and 420Hz. An array of 6-segment LED meters show peak signal level for the four mic pres, in addition to the four direct inputs to the optional A-D card. Switchable rear-panel insert points allow the use of inline processors such as compression.

• Classic ISA mic preamp design featuring Lundahl LL1538 input transformer
• Instrument and line inputs with dedicated input connectors and front-panel switch
• Switchable input impedance including classic ISA 110 setting
• Variable cut-off frequency high-pass filter
• Dedicated switchable insert point
• Per-channel six-segment LED peak-level meters
• Optional A-D card with up to 192kHz, 24-bit sampling via ADAT or AES3
• Brainworx bx_console Focusrite – exclusive plug-in that faithfully captures the sound, feel and styling of the original Focusrite ISA 110 Equaliser and ISA 130 Dynamics Modules.

SPECIFICATIONS

MIC INPUTS

• Frequency Response At Minimum Gain (0dB) (Mic)
  • -0.35dB at 20Hz and –3dB at 122kHz
• Frequency Response At Maximum Gain (60dB) (Mic)
  • –2.5dB at 20Hz and –3dB 103kHz
• Gain Range (Mic)
  • 0dB to 60dB in 10dB steps, plus 0dB to 20dB continuously variable trim
• Maximum Headroom (Mic)
  • 7.4dBu
• Noise EIN (Mic)
  • -126dB (measured at 60dB of gain with 150O termination and 20Hz/22kHz bandpass filter)
• Noise At Main Output With Unity Gain (Mic)
  • -98dBu (measured with a 20Hz/22kHz bandpass filter)
• SNR (Mic)
  • 123dB (relative to max output 25dBu) 120dB (relative to 0dBFS ( 22dBu)
• CMRR (Mic)
  • 88dB
• Input Impedance, Variable (Mic)
  • 600O, 1400O, 2400O, 6800O

LINE INPUTS

• Frequency Response At Unity Gain (0dB) (Line)
  • -0.3dB at 20Hz and –3dB at 94kHz
• Gain Range (Line)
  • -20dB to 10dB in 10dB steps, plus 0dB to 20dB continuously variable trim
• Maximum Headroom (Line)
  • 25.4dBu
• THD N (Line)
  • 0.002 (measured with 4dBu input signal, 0dB gain setting, with a 20Hz/22kHz bandpass filter)
• Noise At Main Output With Unity Gain (Line)
  • -91dBu (measured with a 20Hz/22kHz bandpass filter)
• SNR (Line)
  • 116dB (relative to max output 25dBu) 113dB (relative to 0dBFS 22dBu). Input Impedance: 10kO
• Frequency Response At 10dB Gain (Instrument)
  • -0.2dB at 20Hz and 0dB at 200kHz
• Frequency Response At 40dB Gain (Instrument)
  • -3dB at 20Hz and –3dB at 38.4kHz

INSTRUMENT INPUTS

• Gain Range (Instrument)
  • 10dB to 40dB continuously variable
• Maximum Headroom (Instrument)
  • 11.5dBu
• Noise At Main Output With Minimum Gain ( 10dB) (Instrument)
  • -95dBu (measured with a 20Hz/22kHz bandpass filter)
• Input Impedance (Instrument)
  • >1MO

HIGH PASS FILTER

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

FRONT AND REAR CONNECTIVITY

• 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

WEIGHT AND DIMENSIONS

• Weight
  • 5.5kg (12.2lbs)
• Dimensions
  • 480mm (W) x 88mm (H) x 280mm (D)