The ISA Two from Focusrite is a dual mono microphone preamp featuring transformer based microphone inputs with variable input impedance. Based on the legendary designs found in the Focusrite Forte and Studio consoles, the preamps provides up to 80 dB of gain, while two front panel instrument inputs allow for immediate access to two transparent DIs.
The microphone inputs feature a pair of Lundahl LL1538 transformers with a 3-section winding that results in very low leakage inductance, along with an extended frequency response. To shield them from stray magnetism, each is encapsulated in mu-metal cans. Each channel has a fully-balanced insert point, activated using a front-panel button, making it easy to insert a choice of outboard EQ, a compressor, or limiter.
A premium bonus is the Brainworx bx_console Focusrite SC channel-strip plug-in, a stellar digital emulation of the legendary and rare Focusrite Studio Console. Only 10 of the consoles were ever produced, but you can access its famed sound directly in your DAW.
Features
Microphone Input Transformer
- Includes Lundahl LL1538 input transformers, originally chosen by Rupert Neve for the ISA 110 and one of the best microphone input transformers available
- Zobel network in the ISA circuit (perfected by Rupert Neve) allows the microphone preamp to maintain an extremely flat frequency response across a very wide bandwidth
Gain
- Offers up to 80 dB of clean, distortion-free gain
- ISA topology ensures low-noise even at the highest gain levels
- The transformer supplies 20 dB of gain, while the ISA’s input stage offers up to 60 dB of additional gain on the microphone input
Variable Input Impedance
- Four choices of input impedance, including the original ISA 110 value, allow for matching the preamp to a different microphones, even a vintage type, for the best possible sound
- Impedance is selected using a switch on the front panel
- Impedance choice is remembered even when the unit is switched off and back on
User-Calibrated Metering
- Each channel has an eight-LED array to clearly display the level of the two signals
- Line up the analog levels with digital converters or a DAW by using the calibration knob on the rear panel
- Calibration avoids clipping on input
Instrument and Line Inputs
- Two 1/4″ TS connectors on the front panel provide access to a transparent DI input
- TRS line inputs are available on the rear panel and a front panel switch allows for stepping through them to instantly select required input
Variable High-Pass Filter
- Smooth-sounding, built-in 18 dB/octave high-pass filter per channel
- Same design as the original ISA 110 module
- Ideal for cutting out rumble, thumps and other unwanted low-frequency sounds using the 16 Hz to 420 Hz range
- Easily accessed with a large knob and illuminated button
Balanced Inserts
- Each channel has its own balanced insert point via 1/4″ TRS send and receive connectors
- Allows for a choice of signal processor to be connected and switched in and out using the illuminated switch on the front panel
Focusrite Console Plug-In
Includes Brainworx bx_console Focusrite SC channel-strip plug-in, a stellar digital emulation of the legendary and rare Focusrite Studio Console
Specifications
| Number of Channels | 2 |
| Multi Function | No |
| Inputs | 2 x 1/4″ TS phone Instrument (front panel) 2 x XLR Microphone (rear panel) 2 x 1/4″ TRS phone Line (rear panel) 2 x 1/4″ TRS phone Return (rear panel) |
| Input Impedance | Mic (@ 1 kHz): Low = 600Ω, ISA 110 = 1.4Ω, Medium = 2.4Ω, High = 6.8 kΩ Line: 10 kΩ from 10 Hz to 200 kHz Instrument: >2 MΩ |
| Maximum Input Level | Mic: +7 dBu with a THD+N <0.7% at 1 kHz measured at 0 dB of gain with 150Ω source impedance and 22 Hz to 22 kHz band-pass filter |
| Outputs | 2 x XLR 2 x 1/4″ TRS phone Send |
| Maximum Output Level | +24 dBu with a THD+N <0.01% at 1 kHz measured with 150Ω source impedance and 22 Hz to 22 kHz band-pass filter |
| Phantom Power | +48V, individually switchable |
| Gain Range | Mic: 0 dB to +60 dB in 10 dB steps, plus 0 dB to +20 dB continuously variable trim Line: -20 dB to +10 dB in 10 dB steps, plus 0 dB to +20 dB continuously variable trim Instrument: +10 dB to +40 dB continuously variable trim |
| Frequency Response | Mic @ minimum gain (0 dB): 10 Hz to 135 kHz, -0.5/1 dB Mic @ +60 dB gain: 10 Hz to 115 kHz, -6/-1 dB Line @ unity gain (0 dB): 10 Hz to 80 Hz, -0.3/-1 dB Instrument @ minimum gain (+10 dB): 10 Hz to 115 kHz, -0.1/1 dB Instrument @ maximum gain (+40 dB): 10 Hz to 110 kHz, -2.5/1 dB |
| EIN | -127 dB (60 dB of gain with 150Ω source impedance and 22 Hz to 22 kHz band-pass filter) |
| Noise | Mic: -97 dBu @ output with unity gain (0 dB) and 22 Hz to 22 kHz band-pass filter Line: -97 dBu @ output with unity gain (0 dB), measured with 50Ω source impedance and 22 Hz to 22 kHz band-pass filter Instrument: -95 dBu, minimum gain (+10 dB) with 22 Hz to 22 kHz band-pass filter |
| Signal to Noise Ratio | Mic: 121 dB, with +24 dB maximum output (150Ω source impedance and 22 Hz to 22 kHz band-pass filter) Line: 121 dB, with +24 dB maximum output (50Ω source impedance and 22 Hz to 22 kHz band-pass filter) |
| THD + N | Mic: <0.0007% @ 1 kHz (-20 dBu input signal with +30 dB gain and 22 Hz to 22 kHz band-pass filter) Line: <0.002% @ 1 kHz (0 dBu input signal with +10 dB gain and 22 Hz to 22 kHz band-pass filter) |
| CMRR | Mic Input @ 60 Hz: -94 dB, with +24 dBu maximum output Mic Input @ 10 kHz: -91 dB, with +24 dBu maximum output |
| Crosstalk | Mic: -85 dB (I/P = 0 dBu, gain = 0 dB @ 1 kHz input to channel A, channel B output) Line: -91 dB (I/P = 0 dBu, gain = 0dB @ 1 kHz input to channel A, channel B output) |
| Power Requirements | 100~240 VAC, 50/60 Hz |
| Dimensions | 19 x 11 x 1.7″ (480 x 280 x 44 mm) |
| Weight | 8.2 lb (3.7 kg) |
| Specialties | 18 dB per octave (3-pole) high-pass filter, continuously variable from 16 Hz to 420 Hz (-3 dB) |
Packaging Info
| Package Weight | 12 lb |
| Box Dimensions (LxWxH) | 25.8 x 14.8 x 5.2″ |
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