Focusrite, since 1985 has been a name synonymous with professional studio microphone preamplifiers following the creation of the ISA 110 for Sir George Martin's Neve console at Air Studios. This range of mic pres feature the same core modules are the Focusrite Forte console and Focusrite Studio console, and are often to go-to choice for producers and engineers alike.
ISA ONE Desktop, 1-channel
Focusrite ISA One is a single-channel microphone preamplifier designed to be used when recording microphone, line-level or instrument audio sources. An optional ISA ADN2 analogue to digital card can be retro fit to gain the ability to add the audio from the preamp to a Dante network. See ISA ADN2 for more information.
Microphone or line-level source is connected to the rear facing panel, with microphone input being via balanced 3-pin XLR, and line level input via balanced 6.35mm jack or balanced 3-pin XLR. Note, the two line level inputs are internally linked and therefore shouldn't be used for independent signals. An instrument input can be plugged directly into the front facing panel positioned 6.35mm jack socket. A push button allows the user to select the input type, whilst a second button allows the user to switch between microphone input impedance depending on the microphone type used. The preset impedances are 600ohms (low), 1.4kohms (ISA 110), 2.4kohms (medium), and 6.8kohm (high).
The front facing panel features rotary gain and trim controllers, a on/off high pass filter frequency at the fixed frequency of 75Hz, and on/off push button functionality for phantom power, phase, input impedance, and insert link activation - with insert send and return connectivity located on the rear facing panel. A moving-coil VU is joined by a peak level LED meter ranging from -42 to 0dBFS to provide indication of output level and digital clipping point. The VU can be calibrated using the 'VU cal' button. A second LED meter gives visual aid for the DI or Ext output, with external amp output, paralleled to the DI input, available via 6.35mm jack. A headphone output with corresponding rotary volume controller is positioned to the bottom right of the front facing panel for accessibility.
Although ISA ONE is a desktop unit, a top-mounted carry handle is fitted for easier positioning or transportation.
Optional expansions: ISA ADN2
Frequency response: 20Hz - 20kHz, +/-0.2dB, microphone; +/-0.1dB, line/instrument. Maximum input level: +7dBu, microphone; +25dBu, line; +18dBu, instrument. Signal to noise ratio: 122dB, microphone/line; 100dB, instrument. Dimensions (HxWxD): 104 x 220 x 290mm. Weight: 3.9kg
ISA TWO Rackmount, 2-channel
ISA Two features an independent pair of ISA microphone preamps from the original ISA 110 module, and has been designed for recording vocals, instruments or stereo piano. The preamp provides two transformer-based microphone preamps with the inputs for each channel via 3-pin balanced XLR on the rear facing panel. Line level sources are connected via balanced 6.35mm jack connectors on the rear facing panel whereas instruments can be directly input using 6.35mm jack connections on the front facing panel. A push button allows the user to switch between microphone input impedance depending on the microphone type used. The preset impedances are 600ohms (low), 1.4kohms (ISA 110), 2.4kohms (medium), and 6.8kohm (high).
Along with the instrument level inputs, the front facing panel also features rotary gain and high pass filter frequency from 16Hz to 420Hz; along with on/off push button functionality including phantom power, phase and input impedance for both inputs. Further switching allows filter on/off and insert on/off with insert send and return connectivity located on the rear facing panel. To the right of the front facing panels, dual peak level LED meters ranging from -42 to 0dBFS, provide indication of output level and digital clipping point. A meter calibration control is provided on the rear panel, with default (central) position being 0dBFS = 22dBu. The user is able to adjust from 0dBFGS = 16dBu to 0dBFS = 24dBu. Main on/off power switch is positioned to the right of the front facing panel.
Frequency response: 20Hz - 20kHz, +/-0.2dB, microphone; +/-0.1dB, line/instrument. Maximum input level: +7dBu, microphone; +25dBu, line; +18dBu, instrument. Signal to noise ratio: 122dB, microphone/line; 100dB, instrument. Maximum output level: +24dBu. Dimensions (HxWxD): 44 x 482 x 325mm, 1U. Weight: 3.7kg
ISA 428 MKII Rackmount, 4-channel
This preamplifier has the same functionality as ISA Two, however ISA 428 mkII has four analogue inputs along with the ability to expand to a total of eight channels and enable the preamplifier to be added to a Dante network via the optional ISA ADN8 card.
In addition to the microphone, line, and instrument input for channels 1-4, there are an additional four balanced, 3-pin XLR A-D inputs on the rear facing panel. These inputs come into use when the optional card is installed, however the channel meters on the front facing panel will always signify the level of these inputs regardless of expansion. A 'clock select' button allows the user to select the internal sample frequency: 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, or 192kHz, whilst an 'Ext' button allows the ISA ADN8 A-D card to follow an external Word Clock source, toggling between standard and Dante clock. An LED signifies successful synchronisation.
Optional expansions: ISA ADN8
Frequency response: 20Hz - 20kHz, +/-0.2dB, microphone; +/-0.1dB, line/instrument. Maximum input level: +7dBu, microphone; +25dBu, line; +18dBu, instrument. Signal to noise ratio: 122dB, microphone/line; 100dB, instrument. Dimensions (HxWxD): 88 x 482 x 325mm, 2U. Weight: 7.05kg
Focusrite ISA 828 mkII utilises the same preamps as ISA 428mkII, however with 8 channels, channels 1-8 can be mic/line level input and channels 1-4 can also be used as instrument level inputs. The preamp can be expanded by way of ISA ADN8 to provide access to a Dante network as well as adding features including AES3, S/PDIF, and ADAT signal paths. LED meters are provided for each channel and are positioned on the individual channel strip. The 18dB/octave high pass filter on the ISA 828 mkII is fixed at 75Hz. Analogue to digital inputs and analogue outputs 1-8 are both by way of DB25 female connector.
Optional expansions: ISA ADN8
Frequency response: 20Hz - 20kHz, +/-0.2dB, microphone; +/-0.1dB, line/instrument. Maximum input level: +7dBu, microphone; +25dBu, line; +18dBu, instrument. Signal to noise ratio: 122dB, microphone/line; 100dB, instrument. Dimensions (HxWxD): 88 x 482 x 325mm, 2U. Weight: 7.05kg
Dante Interface Cards
ISA ADN2 analogue to digital, 2-channel
Focusrite ISA ADN2 is compatible with ISA One microphone preamp, and allows implementation directly on a Dante network. The optional two-channel A-D card provides analogue-to-digital conversion and features Dante, AES3, ADAT and S/PDIF connectivity. The card operates at sample rates up to 24-bit/192kHz.
The card offers primary and secondary RJ45 Dante output ports, an AES59 DB25 connector for AES3 output, and a pair of TOSLINK connectors for ADAT output. Word Clock I/O on BNC connectors allows synchronisation with many external devices. RedNet Control and Dante Controller software are included.
System requirements: Mac OS X 10.12 (Sierra) or above; Windows 7 or above.
ISA ADN8 analogue to digital, 8-channel
Focusrite ISA ADN8 enables ISA 428 MkII and ISA 828 MkII to be implemented directly on a Dante network. The optional eight-channel A-D card features Dante, AES3 and ADAT connectivity, and operates at sample rates up to 24-bit/192kHz. Metering and settings are accessed through RedNet Control, routing is configured using Dante Controller.
The card offers primary and secondary RJ45 Dante output ports, an AES59 DB25 connector for AES3 output, and a pair of TOSLINK connectors for ADAT output. Word Clock I/O on BNC connectors allows synchronisation with many external devices. RedNet Control and Dante Controller software are included.
System requirements: Mac OS X 10.12 (Sierra) or above; Windows 7 or above.