ISA 828

ISA 828

More mic inputs for less

You can enjoy the benefits of Focusrite’s classic heritage sound in many ways, but one of the most cost-effective is with the ISA 828, which includes eight Focusrite transformer-based mic preamps in a compact 2U package, along with front panel instrument ins and rear panel line inputs.

The Focusrite ISA mic preamp is based closely on the original design created by Rupert Neve in 1985 for Sir George Martin’s AIR Studios. Virtually unchanged over the years, the ISA mic preamp delivers the warm, full sound that could be just what you’re looking for – and if you use a significant number of microphones at once, the ISA828 is for you.

Additional mic versatility

We just made one significant change to the design, and that was to add three additional input impedances to the original vintage ISA110 setting. Ranging from low to high impedance, the four settings enable you to get the very best sound from a vintage mic – it’s after all what the ISA was originally designed for – but also get a clean, transparent sound from the microphones of today. Or you can enhance a particular feature of your favourite microphones. Indeed, ISA makes the perfect match for any mic. There’s also a vintage design 75Hz / 18dB per octave high pass filter on each channel for detailed control of the bass end.

The ins and the outs

Four front-panel direct instrument inputs are also provided, with high and low impedance settings for extra versatility, and the input side is rounded out by eight TRS rear-panel line inputs. With convenient 25-pin D-type output connectors, ISA 828 is easy to interface with Avid Pro Tools | HD™ and other popular recording systems and consoles. There’s also an optional 8-channel A/D converter available with 122dB dynamic range and sampling up to 192kHz. An insert is available on each channel between the preamp and the A-D. 6-LED meters let you know exactly what is going on, and use the same reference points as Pro Tools | HD.

Pro Tools | HD is a trademark or registered trademarks of Avid Technology, Inc. or its subsidiaries in the United States and/or other countries.

Key Features

Eight ISA series transformer-based preamps

In a single robust 2U chassis, offering the classic Focusrite pre at its lowest cost-per-channel to date.

Optional eight-channel 192kHz A-D converter

Embodies cutting edge conversion technology, incorporating Focusrite analogue circuitry to deliver the best A-D performance on the market, bar none.

Interface easily with Pro Tools and other systems

With convenient 25-pin D-type connectors, ISA 828 integrates quickly and seamlessly with Pro Tools | HD, as well as other popular hard disk recorders and mixing systems.

Direct instrument inputs

Each instrument input features high and low impedance options to provide a comprehensive and accessible DI solution.

Inserting available on every channel

Allows external devices to be inserted between the preamp and the A-D converter, using the 25-pin D-type cable.

Switchable impedance

Selectable per channel; choose one of four carefully selected input impedances, including the original ISA110 setting, to suit any microphones.

High pass filter, polarity reverse and phantom power

Each has a dedicated switch, independent on each channel.

Six LED input meter

Complete with precise meter trim - designed to utilise the same reference points as Pro Tools | HD.

Eight Lundahl LL1538 mic input transformers

The original mic transformer used in the original Red modules helps to provide the unique sound and performance of this groundbreaking design.

Specifications

Mic Inputs

Gain range 0 dB to 60 dB in 10 dB steps
Input Impedance Variable, 600Ω, 1k4Ω, 2k4Ω, 6k8Ω
EIN (equivalent input noise) -126 dB measured at 60 dB of gain with 150 Ohm terminating impedance and 22 Hz / 22 kHz bandpass filter
Noise at main output with gain at unity (0 dB) -97 dBu measured with a 22 Hz / 22 kHz bandpass filter
Signal to noise ratio relative to max headroom (9dBu) 106 dB
THD at medium gain (30dB) 0.0008% measured with a 1 kHz -20 dBu input signal and with a 22 Hz / 22 kHz bandpass filter
Frequency response at minimum gain (0 dB) -0.5 dB down at 10 Hz and –3 dB down at 110kHz
Frequency response at maximum gain (60 dB) –3 dB down at 16 Hz and –3 dB down 85 kHz
CMRR 91.8 dB (Channel 1, 1 kHz, maxiumum gain)
Crosstalk Channel to Channel With 10 dB @ 1 kHz input to chA, chB output = 102 dBrA. With 10 dB @ 10 kHz input to chA, chB output = 84 dBrA

Line Inputs

Gain range -20 dB to +10 dB in 10 dB steps
Input Impedance 10 kΩ from 10 Hz to 200 kHz
Noise at main output with gain at unity (0 dB) -96 dBu measured with a 22 Hz / 22 kHz bandpass filter
Signal to noise ratio relative to max headroom (24 dBu) 120 dB
Signal to noise ratio relative to 0dBFS(+22dBu) 118dB
THD at unity gain (0dB) 0.001% measured with a 0 dBu input signal and with a 22 Hz / 22 kHz bandpass filter
Frequency Response at unity gain (0dB) 0.3 dB down at 10 Hz and –3 dB down at 122 kHz

Instrument Inputs

Gain range 10 dB to 40 dB continuously variable
Input Impedance 1 MΩ or 300 kΩ
Noise at minimum gain (+10 dB) -90 dBu measured with a 22 Hz / 22 kHz bandpass filter
Noise at maximum gain (+40 dB) -62 dBu measured with a 22 Hz / 22 kHz bandpass filter
THD at minimum gain (+10 dB) 0.002% measured with a 10 dBu input signal and with a 22 Hz / 22 kHz bandpass filter
Frequency Response at 10 dB gain with -10 dB input 10 Hz - 200 kHz +/- 0.6 dB
Frequency Response at 40 dB gain with -40 dB input -2.5 dB down at 10 Hz and 0 dB at 200 kHz

Instrument Inputs

Roll off 18 dB per octave 3 pole filter
Frequency Fixed 75Hz measured at the 3dB down point

Weight and Dimensions

Weight 8.84 kg 19.5 lbs
Dimensions (W x H x D) 484mm (W) x 85mm (H) x 305mm (D) (350mm depth with heat sink) 19" (W) x 3.5" (H) x 12" (D) (13.8" depth with heat sink)