Focusrite ISA 828 MkII Classic ISA Mic Preamp

Focusrite ISA 828 MkII – 8-Channel Microphone Preamp with Lundahl Transformers and ISA 110 Circuitry
The Focusrite ISA 828 MkII delivers legendary studio-grade sound with eight classic ISA transformer-based mic preamps. Featuring Lundahl LL1538 input transformers, switchable impedance settings, and front-panel instrument inputs, this rackmount preamp brings iconic analog warmth and clarity to modern production environments. Ideal for permanent studio installations, it provides dedicated line inputs, per-channel metering, and insert points for processing flexibility.

Ready for high-end recording, the ISA 828 MkII offers up to 80dB of gain, a high-pass filter, and is expandable via the optional ISA ADN8 A-D card (sold separately), adding ADAT, AES3, and Dante output options. Whether you're tracking vocals, guitars, or drums, this versatile unit is a must-have for serious engineers and music producers looking for that authentic Focusrite console sound.

At-a-Glance Highlights

• 8 ISA transformer-based mic preamps with Lundahl LL1538 inputs
  
• Switchable input impedance including classic ISA 110 mode
  
• Front-panel instrument inputs (channels 1–4)
  
• Per-channel six-segment LED metering and insert points
  
• High-pass filter: 75Hz, 18dB/octave per channel
  
• Optional ISA ADN8 A-D card for Dante, ADAT & AES3 output
  

Mic Inputs

• Gain Range:
• 0dB to +30dB (30–60 switch disabled)
• +30dB to +60dB (30–60 switch enabled)
• 10dB steps, plus +20dB continuous trim
• Input Impedance:
• 600Ω (Low)
• 1400Ω (ISA 110)
• 2400Ω (Medium)
• 6800Ω (High)
• Max Input Level: +25dBu (min gain, medium Z)
• Frequency Response:
• 10Hz – 122kHz ±3dB (unity gain, medium Z)
• THD+N: -91dB (0.0028%) @ -1dBr, min gain, medium Z
• EIN: -123dBu A-Weighted (typical)
• Signal-to-Noise Ratio: 122dB A-Weighted (typical), medium Z
• CMRR: -65dB @ 997Hz, min gain, medium Z
• High-Pass Filter: 75Hz knee, 18dB/octave (switchable per channel)

Line Inputs

• Gain Range: -20dB to +10dB in 10dB steps, plus +20dB continuous trim
• Input Impedance:
• 470Ω (Low)
• 2.4MΩ (High)
• Max Input Level: +18dBu (min gain, low Z)
• Frequency Response:
• 20Hz – 20kHz ±0.1dB (min gain, low Z)
• 10Hz – 110kHz ±1.2dB (min gain, low Z)
• THD+N: -83dB (0.0071%) @ -1dBr, min gain, low Z
• Signal-to-Noise Ratio: 100dB A-Weighted (typical), min gain, low Z

Instrument Inputs

• Mic Talkback Crosstalk: -80dB (20Hz – 20kHz, min gain, medium Z)
• Line Crosstalk: -80dB (20Hz – 20kHz, min gain, medium Z)
• Instrument Crosstalk: -80dB (20Hz – 20kHz, min gain, medium Z)
  

Connectivity

• Front Panel:
• (2) Channels In
• (4) 1/4" Instrument Jack Inputs
• Rear Panel:
• (8) XLR Mic Inputs
• (8) 1/4" Line-Level Inputs
• (1) DB-25 Line-Level Output (AES59 Standard)
• Line-Level I/O: 8 Inputs / 8 Outputs
• Digital Card Slot:
• Compatible with ISA ADN8 Card
• Power Supply: (1) IEC Input

Operating Conditions

• Operating Temperature: Up to 104°F (40°C)

Physical Specifications

• Dimensions (H x W x D): 3.46" x 18.98" x 12.8"
• Weight: 15.55 lbs (7.05 kg)