Focusrite ISA 428 Mk II

Focusrite ISA 428 Mk II

ISA 428 Mk II (2nd generation) combines four legendary ISA transformer-based mic preamps in a 2U rack enclosure. With selectable input impedance, up to 80 dB of gain and a variable high-pass filter, it delivers classic large-format studio character — from vintage warmth to modern clarity.

✅ 4 × ISA transformer-based mic preamps
✅ Selectable mic impedance (600Ω / 1400Ω / 2400Ω / 6800Ω)
✅ Up to 80 dB gain (60 dB + 20 dB trim)
✅ 4 × Front-panel Hi-Z instrument inputs (>1 MΩ)
✅ 4 × Rear-panel line inputs
✅ Switchable insert points per channel
✅ Variable high-pass filter (16–420 Hz, 18 dB/oct)
✅ 6-segment LED meters per channel
✅ Optional 8-channel A-D converter (122 dB dynamic range)

Mic Inputs:
Gain: 0–60 dB + 0–20 dB trim
EIN: -126 dB
CMRR: 88 dB
SNR: up to 123 dB
Max Headroom: 7.4 dBu

Line Inputs:
Gain: -20 dB to +10 dB + trim
Max Headroom: 25.4 dBu
THD+N: 0.002%

Instrument Inputs:
Gain: 10–40 dB
Max Headroom: 11.5 dBu
Input Impedance: >1 MΩ

Connectivity:
• 4 × XLR line outputs
• 4 × 6.3 mm TRS insert sends
• IEC power input (100–240V)

Form Factor: 2U / 19” rack

In the box:
– ISA 428 Mk II unit

Tags: Focusrite ISA 428 Mk II, ISA 428 Mk II, Microphone preamplifiers