Focusrite ISA 428 MkII: Classic ISA mic preamp
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
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  • Instrument and line inputs with dedicated input connectors and front-panel switch
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  • Switchable input impedance including classic ISA 110 setting
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  • Variable cut-off frequency high-pass filter
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  • Dedicated switchable insert point
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  • Per-channel six-segment LED peak-level meters
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  • Optional A-D card with up to 192kHz, 24-bit sampling via ADAT or AES3

Focusrite ISA 428 MkII: Classic ISA mic preamp

SKU: AMS-ISA428MK2
$1,849.99Price

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)

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