Focusrite - ISA 428 MkII 4-Channel Microphone Preamp

Item # SRSISA428MKII
| Mfg # ISA428MKII
| UPC #
Our Price: $1,499.99
Retail: $1,899.99 | You Save: 21%
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*****5 / 5 (based on 1 Reviews)
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The ISA428 MkII 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.

First introduced in 1985, the ISA microphone preamp holds a reputation for outstanding transparency along with subtle warmth contributed by transformer core saturation. The addition of a variable impedance circuit allows ISA users to perfectly match the preamp with any microphone, or to use different settings creatively to shape the sound of the microphone. Unchanged for decades, the ISA microphone preamp topology offers incredible clarity and the signature Focusrite sound that makes it the top choice among many audio professionals today.

The optional class-leading eight-channel A-D converter option used with the ISA828 is also compatible with the ISA428 MkII. Along with the four mic preamp inputs, four additional inputs allow you to route other line signals through the converter. High quality Burr-Brown Pro Audio Amplifiers and flagship PCM4220 A-D converter chips seated within Focusrite custom analogue circuitry deliver unparalleled performance. Specifications include a dynamic range of 122dB and jitter performance below 250 picoseconds. The card can be retrofitted at any time. Thanks to its convenient 25-pin D-Type connector, it integrates seamlessly with most digital workstations, including Pro Tools.

Four instrument inputs, instantly accessible on the front panel, allow quick and easy connection without the need for a separate DI box. Extra processing can be placed between preamp and conversion via the units dedicated insert points, featured on every channel. Finally, accurate six-segment LED metering is designed to catch even the fastest transients on every channel.

Over 25 years, Focusrite has earned a reputation for bringing superb audio quality and engineering excellence to an array of audio professionals. Whether you're looking to preserve the sound of your classic microphones, or searching for the perfect front end for your digital studio, the ISA428 MkII brings legendary tools to your studio at an exceptional new price.

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 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)
  • CMRR: 88dB. 
  • Input Impedance, variable: 600Ω, 1400Ω, 2400Ω, 6800Ω

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: 10kΩ

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 = >1MΩ

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 1⁄4” TS jack inputs on front panel 
  • 4 microphone XLR inputs on rear panel 
  • 4 line 1⁄4” TRS jacks on rear panel 
  • 4 insert return 1⁄4” TRS jacks on rear panel
  • 4 ADC XLR inputs on rear panel

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

Front Panel Indicators

  • 8 output meters, 6 segment 
  • 4 30-60 mic gain range selection indicator 
  • 4 +48V phantom power indicator 
  • 4 Phase indicator 
  • 4 Insert In indicator 
  • 4 Filter In indicator 
  • 4 Input selection indicators (Mic, Line, Inst) 
  • 4 Z In microphone input impedance selection indicators (Low, ISA110, Med, High) Clock select indicators (44.1, 48, 88.2, 96, 176.4, 192) 
  • 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)

Overview
*****5/5
Based on 1 Reviews
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Product Reviews
  • *****
  • Classic ISA Sound
  • May 25, 2013
  • By: Gary

I bought this unit along with the Focusrite ISA828 A/D Card to utilize the extra 8 channels of ADAT I/O I had on my Apogee Symphony and couldn't be happier! My main vocal mic for recording has always been the SM7b by Shure but it requires a lot of extra gain to make it worth while. Thats where the ISA fits in perfectly. With most basic preamps as you add gain most of the time your also adding more noise to your recordings as well. This isn't the case with the ISA428 MkII, It stays perfectly clean and apparent as you increase the gain without being a unpleasant or "sterile" sounding clean. I had a session lined up shortly after buying this pre and I told the artist that I wanted to test out some new gear on him seeing that we have worked together for a while and I know how he sounds fairly well now. After a few takes he instantly stops and says "Everything is so much more clear and apparent now. Im going to really have to step up my vocals this time." I think that speaks well enough for this product. A+ on this one Focusrite!

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Product Warranty Information

 
Focusrite
 
Tel: (866) 362-8774; Email: support@focusrite.com; Focusrite Website | Website Contact | Warranty Info; 1 year Parts and Labor

 

 
All instruments in our catalogs and on our shopping site carry the manufacturers' warranties against defects in parts and workmanship. Should a defect occur within the manufacturer's warranty period, contact us immediately.

We will be glad to help facilitate the repair or replacement as specified by the manufacturer. The manufacturer will determine whether the defect is covered under their warranty; we do not make that determination.

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All warranties, stated or implied are held with the product manufacturer and they vary from item to item. Consult the documentation that came with your product for details in addition to the information below.
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Focusrite was established in 1985 and the founding principles of the company were to develop products that sounded more musical, in addition to just measuring well. Based just outside of London, they work with the best design talent throughout the world.