The ISA828 eight-channel microphone preamplifier provides eight original ISA transformer-based preamps 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 preamps feature the same classic microphone preamplifier design as the original ISA110 module from Focusrite's critically acclaimed Forté console (including the original Lundahl L1538 transformer and bespoke zobel network).
The preamps are complemented by eight line inputs, eight line outputs and an optional eight channel 192kHz A-D converter boasting a dynamic range of 122dB. 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 preamp with any microphone, thus maximising 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 preamp 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.
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.
|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|
|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|
|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|
|Roll off||18 dB per octave 3 pole filter|
|Frequency||Fixed 75Hz measured at the 3dB down point|
|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)|