ISA 828 MkII

Description

Sharing the simple mic preamp design of the original Focusrite ISA 110 module from the Focusrite Studio Console, the ISA 828 MK2 features eight of Focusrite’s classic mic preamps, each equipped with Lundahl LL1538 transformers on every input. Each channel offers mic or line input options, while channels 1-4 also feature instrument inputs on the front panel. Each mic preamp has variable input impedance, providing a range of subtly different tonal options when using microphones, including an "ISA 110" setting that replicates the impedance of the original Focusrite mic preamp.

It provides up to 60 dB of gain, plus an additional +20 dB of continuously variable trim, offering a total gain range of 80 dB. The fixed-frequency 75 Hz high-pass filter features an 18 dB/octave roll-off. The ISA 828 MK2 includes high-pass filters, six-segment LED meters per channel, and switchable insert points on the rear panel, allowing the integration of outboard processors such as compressors or equalizers.

Dedicated connectors for mic and line inputs allow all sources to be connected simultaneously, making the ISA 828 MK2 ideal for permanent rack installations. A key update in the ISA 828 MK2 is its upgraded power supply, which improves energy efficiency, reduces heat generation, and ensures highly reliable operation. The optional ISA ADN8 A-D expansion card provides eight Dante, ADAT, and AES3 outputs at resolutions up to 24-bit/192 kHz.

Key Features

• Classic ISA Mic Preamp Design with Lundahl LL1538 Input Transformer
• Switched-Mode Power Supply Design – Enables efficient and cool operation
• Front-Panel Instrument Inputs on Channels 1-4 – Offers two impedance options: High (2.4 MΩ) and Low (470 kΩ)
• Dedicated Line Input Connectors – With front-panel switch for easy selection
• Selectable Input Impedance – Includes the classic ISA 110 setting
• High-Pass Filters
• Switchable Insert Points – When used with the A-D card
• Six-Segment Peak LED Meters Per Channel – Calibratable for precise level monitoring
• Optional A-D Card – Supports up to 192 kHz and 24-bit resolution, providing high-precision digital audio conversion to Dante, ADAT, and AES3 (sold separately)

Detailed Specifications:

Microphone Inputs

• Gain Range: 0 dB to +30 dB (30-60 switch off) and +30 dB to +60 dB (30-60 switch on) in 10 dB steps, with an additional continuous adjustment of +20 dB
• Input Impedance: Low = 600Ω, ISA 110 = 1400Ω, Med = 2400Ω, High = 6800Ω
• Max. Input Level: +7 dBu, minimum gain, medium Z
• Frequency Response (20 Hz - 20 kHz): 20 Hz - 20 kHz ±0.2 dB, minimum gain, medium Z
• THD+N: -91 dB (0.0028%) @ -1 dBr, minimum gain, medium Z
• EIN: -123 dBu 'A'-weighted (typical)
• Signal-to-Noise Ratio: 122 dB 'A'-weighted (typical), medium Z
• Common Mode Rejection Ratio (CMRR): 997 Hz CMRR: -93 dB, minimum gain, medium Z
• Phantom Power: +48 V, independently switchable per channel
• High-Pass Filter: 75 Hz frequency, 18 dB/octave, independently switchable per channel
• Phase: Inverts the phase of the selected input
• Frequency Response (10 Hz - 110 kHz): 10 Hz - 110 kHz ±1.5 dB, minimum gain, medium Z

Line Inputs

• Gain Range: 20 dB to +10 dB in 10 dB steps, with an additional continuous adjustment of +20 dB
• Input Impedance: Low = 600Ω, ISA 110 = 1400Ω, Med = 2400Ω, High = 6800Ω
• Max. Input Level: +25 dBu, minimum gain, low Z
• Frequency Response (20 Hz - 20 kHz): 20 Hz - 20 kHz ±0.1 dB, minimum gain, low Z
• THD+N: -91 dB (0.0028%) @ -1 dBr, minimum gain, low Z
• Signal-to-Noise Ratio: 122 dB 'A'-weighted (typical), minimum gain, low Z
• Frequency Response (10 Hz - 122 kHz): 10 Hz - 122 kHz ±3 dB, minimum gain, low Z

Instrument Inputs

• Gain Range: +10 dB to +40 dB with continuous gain control via trim pot

Front Panel Connectivity

• Number of Channels: 2 Input Channels
• Instrument Inputs: 4 x 1/4" jack inputs

Rear Panel Connectivity

• Microphone Inputs: 8 x Female XLR
• Line Level: 8 Inputs and 8 Outputs
• Line Inputs: 8 x 1/4" jack inputs
• Outputs: 1 x DB-25 connectors (AES59)

Inserts

• Number of Channels: 8 In
• Input: 1 x DB-25 connectors (AES59)

Digital Card Slot

• Compatible Card: ISA ADN8

Front Panel Indicators

• Control Functions: 16 x Pots (Gain and Trim), 60 Switches (On/Off, 30-60 Gain, +48V, Phase, HPF, Insert, Input Z, Input, Pre A-D Meters, Clock Selection, and Ext. Word Clock)

Rear Panel Indicators

• Control Functions: 1 x Pot (Meter Trim)