FOCUSRITE ISA 828 MKII 8-channel Preamp

8-channel preamplifier

The FOCUSRITE ISA 828 MKII is an 8-channel preamplifier, featuring Lundahl LL1538 transformers on every microphone input. Its circuit design is based on the original ISA 110 module implemented in the legendary Focusrite Studio Console.
Each of the 8 channels offers XLR microphone inputs and ¼” TRS jack line inputs located on the rear panel. On the left side of the front panel, there is also a ¼” jack instrument (HiZ) input for each of the first 4 channels. Input selection for each channel (Mic, Line, or HiZ for the first 4; Mic/Line for channels 5 to 8) can be made via a convenient button. A red LED indicates the selected input for the preamp stage.
For the microphone inputs, you can choose between 4 different impedances using a dedicated button: LOW (600Ω), ISA110, MID (2400Ω), and HIGH (6800Ω). As one might guess, the ISA110 impedance replicates the 1400Ω input impedance of the eponymous preamplifier module implemented in the Focusrite Console. In this case too, a red LED will indicate the selected setting.
On the microphone inputs, a gain range of up to +80dB is available! A button allows selecting two different ranges (30 and 60dB) for the microphone inputs, which are then controlled by the stepped GAIN potentiometer. By selecting “30”, a gain of 0, 10, 20, or 30dB can be set. When operating with the range set to “60”, a gain of 30, 40, 50, or 60dB can be assigned to the microphone input by choosing one of the 4 options with the GAIN potentiometer. For line inputs, the GAIN operates at -20, -10, 0, or +10dB. Should additional gain be needed, the TRIM potentiometer provides an additional +20dB of gain in Mic/line mode; from +10 to +40dB in instrument (HiZ) mode.
Each channel also features 6-segment peak LED meters (calibratable) and individual backlit switches for activating/deactivating +48V phantom power, phase inversion, the high-pass filter, and the Insert (the latter only when used with a digital card).
The analog output of the 8 preamplified channels (ANALOGUE OUTPUTS) is via a female DB25 connector (Tascam standard pin-out) for convenient and secure connection to the line inputs of audio interfaces or patch-bays with DB25 connectors, or by using a classic cable snake (NOT included) from male DB25 to 8 TRS or XLR Jacks. An additional DB25 connector labeled “ADC INPUTS”, also wired to Tascam/Pro Tools standard, allows direct sending of 8 analog channels to the digital card (if installed) for A-D conversion. This connection essentially functions as a “return” if external signal processors (compressors, EQ, etc.) are to be used. By utilizing the Insert function (button available on each channel), the signals from the sources connected to the inputs of the FOCUSRITE ISA 828 MKII will go from the analog out to the input of the processors, and then return to the ADC input. The outputs of the processors must obviously be connected to this ADC input.
The FOCUSRITE ISA 828 MKII comes with (via download, upon registration on the manufacturer's website) the Brainworx bx_console Focusrite plug-in, the virtual channel strip that emulates the legendary and coveted Focusrite ISA 110 (equalizer) and ISA 130 (dynamics processor) modules.
The FOCUSRITE ISA 828 MKII uses a new generation switching power supply, which ensures improved energy efficiency and reduces heat generation.

Specifications

• 8 XLR microphone inputs
• Lundahl LL1538 transformers on every mic preamp
• 4 selectable impedances on every mic preamp (Including the 1400Ω of the historic ISA 110 module)
• 8 line inputs on ¼” TRS jacks
• ¼” instrument (Hi-Z) Jack inputs on the first 4 channels
• 60dB Gain, plus 20dB Trim (80dB total range)
• Mic/line/HiZ switch on the front panel
• SLOT for ISA ADN8 card (A-D conversion (up to 192kHz, 24-bit))
• Digital conversion in DANTE, ADAT, and AES3 formats
• 6-segment peak LED meters (calibratable) on every channel
• 48V phantom power and high-pass filter on every channel
• New Switching power supply (improved energy efficiency and low heat emission)
• Switchable insert points when used with optional A-D card
• Brainworx bx_console Focusrite plug-in included