Eight ISA series transformer-based pre amps
In a single robust 2U chassis, offering the classic Focusrite pre at its lowest cost-per-channel to date.

New Optional Eight Channel 192kHz ADC
Embodies cutting-edge conversion technology, incorporating Focusrite analogue circuitry to deliver the best A/D performance on the market, bar none

Convenient 25 pin D-Type connectors
The ISA828 integrates quickly and seamlessly with ProTools HD, as well as other popular hard disk recorders and mixing desks.

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

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 pre amp and the ADC, using the 25-pin D-type cable.

High pass filter, Phase 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 Digidesign’s HD™

Mic Input Response
• Gain range: 0dB to 60dB in 10dB steps
• Input Impedance, variable: 600?, 1k4?, 2k4?, 6k8?
• EIN (equivalent input noise): -126dB measured at 60dB of gain with 150 Ohm terminating impedance and 22Hz/22kHz bandpass filter
• Noise at main output with gain at unity (0dB): -97dBu measured with a 22Hz/22kHz bandpass filter
• Signal to noise ratio relative to max headroom (9dBu): 106dB
• THD at medium gain (30dB): 0.0008% measured with a 1kHz -20dBu input signal and with a 22Hz/22kHz bandpass filter
• Frequency response at minimum gain (0dB): -0.5dB down at 10Hz and –3dB down at 110kHz
• Frequency response at maximum gain (60dB): –3dB down at 16Hz and –3dB down 85kHz
• CMRR: 91.8dB (Channel 1, 1kHz, maxiumum gain)
• Crosstalk Channel to Channel: with 10dB@1kHz input to chA, chB output =102dBrA. With 10dB@10kHz input to chA, chB output = 84dBrA

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

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

High Pass Filter
• Roll off: 18dB per octave 3 pole filter
• Fixed Frequency 75Hz measured at the 3dB down point

Weight
• 8.84kg
• 19.5Ibs

Dimensions
• 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)

The ISA828 eight channel microphone pre-amplifier provides eight original ISA transformer-based pre amps in a single robust 2U chassis, offering the Focusrite signature sound at its lowest cost per channel to date.

The eight ISA-series transformer-based microphone pre amps feature the same classic microphone pre-amplifier design as the original ISA110 module from Focusrite's critically acclaimed Forte console (including the original Lundahl L1538 transformer and bespoke zobel network).

The pre-amps are complemented by eight line inputs, eight line outputs and an optional eight channel 192kHz ADC boasting the widest dynamic range of any converter to date. Thanks to its convenient 25 pin D-Type connectors, the ISA828 also integrates quickly and seamlessly with ProTools HD, as well as other popular hard disc recorders and mixing desks.

The microphone input stage additionally includes a variable impedance circuit, allowing the user to switch between four carefully selected input impedance settings. The original ISA110 setting is supplemented by three further impedance settings to either perfectly match the pre-amp with any microphone, thus maximizing level, or to use different settings creatively to shape the sound of the microphone being used.

The four front panel instrument inputs also feature high and low impedance options to provide a comprehensive and accessible DI solution. Insert switches are also featured on every channel, should the need arise to place extra processing between the pre amp and converter. Vintage design 75 Hz / 18dB per octave high pass filters are also provided on every channel, ensuring unwanted low frequencies are effectively eliminated.

The ISA828’s new optional eight-channel 192kHz ADC is the first audio ADC to utilise Texas Instruments Burr-Brown Pro Audio Amplifiers and Flagship Analog to Digital Converter PCM4220 chips. This cutting-edge technology is encompassed within Focusrite’s own custom analogue circuitry to provide eight channels of unparalleled A/D conversion, delivering a dynamic range of 122dB and jitter at less than 250 picoseconds.

Finally, every channel features a six LED input meter, complete with global precise meter trim. Metering has been designed to utilise the same reference points as Digidesign’s Pro Tools HD™ system and provides clear and accurate input metering, independent of the DAW.

The ISA microphone pre-amplifier was first introduced back in 1985. This transformer-based pre-amplifier 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 microphone pre-amplifier 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 pre-amp 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 pre amp is renowned for its transparency, but there's also that 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 pre-amp must operate over a far greater bandwidth. The extremely broad frequency response of Focusrite pre-amps - 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.