Focusrite ISA 428 MKII 4 Channel Classic ISA Mic Preamp/DI

Focusrite ISA 428 MKII 4 Channel Classic ISA Mic Preamp/DI

Featured with Focusrite's transformer-based preamps, the Focusrite has designed the ISA428 MkII which is a 4-channel microphone preamp. The unit is an ideal front end for the audio professional, whether utilizing digital or analog recording, with selectable input impedance, direct instrument inputs and an optional 8-channels of high-quality analog to digital conversion. 

Features:

• Four ISA Series Transformer-Based Preamps: SA series microphone preamps have been the producers' choice on countless hit records over the last two decades
• Selectable Impedance: Ideal for microphone matching or extended microphone creativity - settings include the "Vintage ISA110" setting that provides the original Focusrite signature sound
• Variable High-Pass Focusrite Filter: Provided on every channel, this is the same filter as featured on the original ISA428
  

Focusrite ISA428 MkII Specs

• Number of Channels: 4
• Inputs: 4 x XLR Microphone (rear panel) 4 x 1/4" TS phone Instrument (front panel) 4 x 1/4" TRS phone Line (rear panel) 4 x 1/4" TRS phone Insert Return (front Panel) 4 x XLR ADC Input for optional AD converter card (rear panel)
• Output: 4 x XLR Line (rear panel) 4 x 1/4" TRS phone Insert Send (rear panel)
• Phantom Power: +48V individually switchable
• Multi Function: Has provision for optional analog to digital converter
• Gain Range: Microphone: 0dB to +60dB in 10dB steps, plus 0dB to +20dB continuously variable trim Line: -20dB to +10dB in 10dB steps, plus 0dB to +20dB continuously variable trim Instrument: +10dB to +40dB continuously variable
• Input Impedance: +48V individually switchable
• Phantom Power: Microphone: 600Ω, 1.4kΩ, 2.4kΩ, 6.8kΩ Line: 10kΩ Instrument: >1MΩ
• Maximum Output Level: Microphone: +7.4dBu Line: +25.4dBu Instrument: +11.5dBu
• Frequency Response:Microphone: -0.35dB at 20Hz and -3.0dB at 122kHz (0dB gain) and -2.5dB at 20Hz and -3.0dB at 103kHz (60dB gain) Line: -0.3dB at 20Hz and -3dB at 94kHz (0dB gain) Instrument: -0.2dB at 20Hz and 0dB at 200kHz (+10dB gain) and -3.0dB at 20Hz and -3.0dB at 38.4kHz (+40dB gain)
• THD + N: Microphone: 0.0009% (measured at 1kHz, -20dBu input signal, at 30dB gain setting, with a 20Hz/22kHz bandpass filter) Line: 0.002% (measured with +4dBu input signal, 0dB gain setting, with a 20Hz/22kHz bandpass filter) Instrument: 0.006% (measured with -20dBu input signal, at minimum gain (+10dB), with a 20Hz/22kHz bandpass filter)
• Noise:
  Microphone:
  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)
  Line:
  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) Microphone: 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) Line: 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)
  Instrument:
  Noise at main output with minimum gain (+10dB): -95dBu (measured with a 20Hz/22kHz bandpass filter) Noise at main output with minimum gain (+10dB): -95dBu (measured with a 20Hz/22kHz bandpass filter)
  
• CMRR: Microphone: 88dB
• Meters: Each 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
• Power Requirements: 100VAC~240VAC
• Dimensions (WxDxH): 19 x 11 x 3.5" (483 x 279 x 89mm)
• Weight: 12.2 lbs (5.5kg)

• High Pass Filter Roll off = 18dB per octave 3 pole filter Frequency range: 16Hz to 420Hz (continuously variable, measured at the 3.0dB down point)

• Package Weight: 17.55 lb
• Box Dimensions (LxWxH): 25 x 18 x 9"