Focusrite ISA428 MkII 4-Channel Mic Preamp - Four classic
preamps with DI inputs and a premium eight channel A-D converter
option. ISA series mic preamps have been the producers’ choice on
countless hit records over the last two decades.
The ISA428 mk2 provides four of Focusrite’s prestigious
transformer-based microphone preamps. It features the same classic
circuitry and renowned audio quality found in the original at a new
level of affordability. With selectable input impedance, direct
instrument inputs and an optional eight channels of high-quality
analogue to digital conversion, the ISA428 MkII creates the perfect
front end for the discerning recording professional.
The Focusrite ISA 428 Mark II features four additional A-D
converter inputs allow eight channels of high-quality conversion,
with a dynamic range of 122dB and jitter performance below 250
picoseconds.
Ideal for mic matching or extended microphone creativity.
Settings include the ‘Vintage ISA110’ setting, providing the
original Focusrite signature sound.
Focusrite ISA428 MkII 4-Channel Mic Preamp Main
Features:
Four ISA-series transformer-based pre-amps
Over the past three decades, ISA mic preamps have contributed
to many of the world’s most significant albums.
Eight Channel optional A/D converter with 122dB dynamic range.
The same cutting-edge analogue to digital converter card used
in the ISA828. Four additional ADC inputs allow eight channels of
high quality conversion.
Switchable Impedance
Ideal for mic matching or extended microphone creativity.
Settings include the 'Vintage ISA110' setting, providing the
original Focusrite signature sound.
Four front panel instrument inputs
Instant access on the front fascia - no separate DI box
required.
Dedicated analogue insert points
Switchable insert points are featured on every channel,
allowing routing (between pre-amp and output) to additional
external processing.
Variable high pass Focusrite filter
Provided on every channel, this is the same filter as featured
on the original ISA110 and the legendary Focusrite forte
console.
Accurate LED meters for every channel
Clear metering designed to catch even the fastest and most
elusive of transients.
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)
Focusrite ISA428 MKII 4-Channel Mic Preamp Specifications
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 150 ohm
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 as follows:
Switched Impedance setting : Equivalent Input Impedance at
1kHz
Low : 600 ohms
ISA110 : 1400 ohms
Med (Medium) : 2400 ohms
High : 6800 ohms
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: 10k
ohms
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 = >1M ohm
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
Focusrite ISA428 MKII 4-Channel Mic Preamp - Front and Rear
Connectivity