Focusrite Pro ISA428 MkII - Microphone Preamp
Features
- 4 Channels
- Transformer Based
- Selectable Impedance
- Phantom Power
Description
The ISA428 MkII from Focusrite is a four-channel microphone preamp featuring Focusrite's transformer-based preamps. With selectable input impedance, direct instrument inputs and an optional eight channels of high-quality analogue to digital conversion, the unit is a perfect front end for the audio professional, whether utilising digital or analogue recording.
The ISA microphone preamp holds a reputation for delivering transparency along with subtle warmth derived from transformer core saturation. The addition of a variable impedance circuit allows users to perfectly match the preamp with any microphone, or to use different settings creatively to shape the sound of the microphone.
The extremely broad frequency response of Focusrite preamps (close to 200kHz at the top end) guarantees accurate phase response across the range of human hearing, with the roll-off point being moved entirely outside of the audible hearing range. Warmth, plus beautifully open, unrestricted high frequencies, is a classic hallmark of the mid 80's Focusrite designs to which this preamp owes its design.
The optional eight channel analogue convertor utilises high-quality Burr-Brown amplifiers and PCM4220 A-D convertor chips seated within Focusrite's custom analogue circuitry. Specifications include a dynamic range of 122dB and jitter performance below 250 picoseconds. The card can be retrofitted at any time and due to the convenient 25-pin D-type connector, it integrates seamlessly with most digital workstations, including Pro Tools.
Key Features:
Four ISA Series Transformer-Based Preamps
ISA series microphone preamps have been the producers' choice on countless hit records over the last two decades
Eight-Channel Optional A-D Convertor
Four additional A-D convertor inputs allow eight channels of high-quality conversion, with a dynamic range of 122dB and jitter performance below 250 picoseconds
Selectable Impedance
Ideal for microphone matching or extended microphone creativity - settings include the "Vintage ISA110" setting that provides 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) through additional external processing
Variable High-Pass Focusrite Filter
Provided on every channel, this is the same filter as featured on the original ISA428
Accurate LED Metres for Every Channel
Clear metering designed to catch even the fastest and most elusive of transients
Additional Features
- Phantom power available on every channel
- Trim control allows 20dB of extra gain with fine adjustment
- Phase reverse buttons help to correct phase issues with microphones or cables
- Optional A-D convertors easily synchronise to external Wordclock
Specifications
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 convertor 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 analogue to digital convertor |
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 | Microphone: 600O, 1.4kO, 2.4kO, 6.8kO Line: 10kO Instrument: >1MO |
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 150O 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) |
CMRR | Microphone: 88dB |
Metres | Each 6-LED metre is calibrated 0dBFS = +22dBu (the maximum level which can be correctly converted by the optional internal A/D convertor before overload occurs). The metre calibration points are as follows:Metre 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) |
Specialities | 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) |
In The Box
- Focusrite Pro ISA428 MkII - Microphone Preamp
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Details
- Product: Focusrite Pro ISA428 MkII - Microphone Preamp
- Manufacturer: Focusrite
- Model: ISA428MK2
- SKU: ISA428MK2
- RM Product #: 44743
- Warranty: 3 year manufacturer warranty