Description
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.
Features
- Classic ISA mic preamp design featuring Lundahl LL1538 input transformer
- Switchable input impedance including classic ISA 110 setting
- Dedicated switchable insert point
- Optional A-D card with up to 192kHz, 24-bit sampling via ADAT or AES3
- Instrument and line inputs with dedicated input connectors and front-panel switch
- Variable cut-off frequency high-pass filter
- Per-channel six-segment LED peak-level meters
Specifications
Mic Inputs
- Frequency response at minimum gain (0dB): -0.35dB at 20Hz and ÛÒ3dB at 122kHz
- Frequency response at maximum gain (60dB): ÛÒ2.5dB at 20Hz and ÛÒ3dB 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 150ë© 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.åÊ
- Input Impedance, variable: 600ë©, 1400ë©, 2400ë©, 6800ë©
Line Inputs
- Frequency Response at unity gain (0dB): -0.3dB at 20Hz and ÛÒ3dB 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: 10kë©
Instrument Inputs
- Frequency Response at +10dB gain: -0.2dB at 20Hz and 0dB at 200kHz
- Frequency Response at +40dB gain: -3dB at 20Hz and ÛÒ3dB at 38.4kHz
- Gain range: +10dB to +40dB continuously variable
- Maximum headroom: +11.5dBu
- THD+N: 0.006% (measured with ÛÒ20dBu 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 = >1Më©
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 1ã4Û TS jack inputs on front panelåÊ
- 4 microphone XLR inputs on rear panelåÊ
- 4 line 1ã4Û TRS jacks on rear panelåÊ
- 4 insert return 1ã4Û TRS jacks on rear panel
- 4 ADC XLR inputs on rear panel
Analogue Audio Outputs (Outputs 1-4)
- 4 line XLR outputs on rear panelåÊ
- 4 insert send 1ã4Û TRS jacks on rear panel
Other I/O
- IEC power input connector 100Vac ÛÒ 240Vac
Front Panel Indicators
- 8 output meters, 6 segmentåÊ
- 4 30-60 mic gain range selection indicatoråÊ
- 4 +48V phantom power indicatoråÊ
- 4 Phase indicatoråÊ
- 4 Insert In indicatoråÊ
- 4 Filter In indicatoråÊ
- 4 Input selection indicators (Mic, Line, Inst)åÊ
- 4 Z In microphone input impedance selection indicators (Low, ISA110, Med, High) Clock select indicators (44.1, 48, 88.2, 96, 176.4, 192)åÊ
- 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)
