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 microphonepreamp 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 microphonepreamp 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 micpreamp 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.
The ISA Pre The ISA microphonepreamplifier was first introduced back in 1985. This transformer-based preamplifier formed the first half of the ISA110 mic pre and EQ module on Focusrite's critically acclaimed Forte console. This console, and the later Studio console were hailed by many as the finest sounding consoles ever built.
The ISA microphonepreamplifier went on to form the cornerstone of all ISA and RED Focusrite products. The topology has never changed, except for the addition of a variable impedance circuit, allowing ISA users to either perfectly match the preamp with any microphone, thus maximizing level, or to use different settings creatively to shape the sound of the microphone being used. The original ISA110 setting was supplemented by three further impedance settings.
The Focusrite preamp is renowned for its transparency, but there's also a subtle warmth that transformer core saturation contributes. This seeming contradiction of warmth plus beautifully open, unrestricted high frequencies, is a classic hallmark of the mid 80's Focusrite designs.
With processors whose bandwidth is strictly limited to the audible (20Hz to 20kHz) bandwidth alone, significant roll-off can still occur, affecting the higher audible frequencies of the signal. Therefore, in order to capture every subtle nuance, exactly as it occurs whilst avoiding any roll-off, the preamp must operate over a far greater bandwidth. The extremely broad frequency response of Focusrite preamps - close to 200kHz at the top end - guarantees accurate phase response across the much narrower range of human hearing, the roll-off point being moved entirely outside of the audible hearing range.
Four ISA series transformer-based preamps ISA series mic preamps have been the producers' choice on countless hit records over the last two decades.
Eight-channel optional A-D converter 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. More information can be found here.
Selectable 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 analogueinsert 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 meters for every channel Clear metering designed to catch even the fastest and most elusive of transients.
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 converters easily synchronise to external word clock
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) NoiseEIN: -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 PassFilter 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
AnalogueChannel Inputs (Inputs 1-4) 4 instrument 1⁄4" TSjack inputs on front panel 4 microphoneXLR inputs on rear panel 4 line 1⁄4" TRS jacks on rear panel 4 insertreturn 1⁄4" TRS jacks on rear panel 4 ADCXLR inputs on rear panel
AnalogueAudio Outputs (Outputs 1-4) 4 line XLR outputs on rear panel 4 insertsend 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 micgain range selection indicator 4 +48Vphantom 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)
Performance Audio is an authorized Focusrite dealer. The Focusrite brand was established way back in 1985 and the founding principles of the company were to develop products that sounded more musical, in addition to just measuring well - today,we still carry these founding principles forward in our class-leading and award-winning designs. We measure our success by the success of you, our clients, and you will find Focusrite product prominent in professional and project studios throughout the world.
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About Performance Audio
Founded by S. Kevin Lewis, Performance Audio has been a primary supplier of professional sound systems and equipment both regionally and nationally since 1977.
Based in Salt Lake City, Utah, Performance Audio has serviced the sound system needs of touring entertainers, business and trade shows, as well as the film and video production industry for over 30 years.
In the late 1980's Performance Audio opened one of the region's first Pro Audio wholesale electronics supply stores. This allowed much more efficient distribution of equipment to a rapidly growing national customer base. This division of Performance Audio now provides over 60% of the company's revenue.
In 1990 Performance Audio began providing designs and equipment for Theme Parks, Amusement Attractions, and Trade Shows. This exciting new area has allowed Performance Audio to expand its horizons even further into the entertainment and communication world. Successful designs and installations include many of the industry's most recognizable names in Las Vegas and Florida. Just prior to the 2000 Summer Olympics, Performance Audio was contracted by Technifex, a leading special effects creator and design firm, and Fox Studios, to design and install special effects audio systems for their Titanic attraction in Sydney, Australia.
While its business was largely based on the concert stage for the first decade, Performance Audio became increasingly more involved with system design and installation for all types of performance and entertainment space, as well as broadcast and recording studio design and supply. As the digital age arrived, Performance Audio became a leader in digital workstation technology, and has working systems in place with film and video producers, CD replicators and tape duplicators, as well as numerous recording and broadcast studios. Performance Audio is Growing!
2014 was a big year for Performance Audio, we expanded our services and brought both GTS (General Theatrical Supply) and BackBeats: Drum and Backline onto our team! Now, we are more capable than ever before to service all your needs!
Here's some updated information to help you reach us:
Salt Lake City
2456 S. West Temple
Salt Lake City, UT 84115
1420 West Center Street
Orem, UT 84057
Salt Lake City
2456 S. West Temple
Salt Lake City, UT 84115
GTS now shares the Performance Audio building!
The GTS people you know and love are here!
Salt Lake City
2456 S. West Temple
Salt Lake City, UT 84115
BackBeats now shares the Performance Audio building!
The BackBeats people you know and love are here!