The Focusrite ISA Two mic preamp gives you the sonic essence of the legendary Forte and Studio consoles in a single rack unit chassis. You get two channels, with inputs for microphone, line-level, and direct instrument-level sources. A variable impedance selector also lets you dial in the warmth you want without sacrificing clarity. If warmth, transparency, and useful features are on your preamp wishlist, check out the Focusrite ISA Two.
Focusrite's ISA Two mic preamp has a distinguished heritage. Since its 1985 introduction, the transformer-based Focusrite pre amp has become something of a legend - and a benchmark for transparency. But there's something else going on. That something is a subtle warmth, courtesy of transformer core saturation. It's this apparent contradiction of warmth plus transparently open and unrestricted high frequencies, that identifies the Focusrite "sound" that continues to be in demand in top studios worldwide.
The Focusrite ISA Two has some innovative thinking under its bonnet. Just what engineering innovations contribute to a superior-sounding mic preamp? For one thing, to eliminate the audible rolloff exhibited by preamps limited to the audible bandwidth, Focusrite ISA pres operate over a much greater range (10Hz-135kHz, in the case of the ISA Two). There's also the ISA topology that gives you up to 80dB of undistorted gain. How about variable input impedance, which lets you fine-tune the amount of "character" in your signal - from pristine transparency, to vintage warmth.
Rupert Neve selected the Lundahl LL1538 as the input transformer for the legendary Focusrite ISA 110, and it's still the best microphone input transformer available - Focusrite specifies it in every one of their ISA Series mic pres. Mr. Neve also perfected the Zobel network (found in Focusrite's ISA circuit), which is responsible for the broad-bandwidth, ruler-flat frequency response exhibited by ISA preamps.
Focusrite's ISA Two brings together a totally independent pair of legendary ISA microphone preamps from the original ISA 110 module, combining the best of traditional solid-state electronics with the original input transformer specified by Rupert Neve — the Lundahl LL1538. Two is a nice round number ideal for recording, say, a vocal and an instrument, or a stereo piano. But though you may only need two mic pres, you owe it to your craft to choose the best. (And if you need more, we offer ISA 428 Mk II 4-channel and ISA 828 8-channel units too.) We've made one little adjustment to the mic pre. The original ISA 110 had a single input impedance that was ideal for the mics of the time. We've added three more, allowing you to get the very best out of any microphone, vintage or modern. Give a vintage mic the input it expects to get a traditional, warm sound. Pair the ISA Two with modern microphones and get the most transparent sound imaginable. Or experiment and pull out the inner character of any microphone you care to try. Couple that with up to 80dB of gain and you can be ready for anything. In addition to the mic pres, there are front panel instrument inputs for instant access, along with rear-panel line ins. There's also a balanced insert point on the rear panel, actuated with a front-panel button so you can insert the EQ, dynamics or other processors you need. Add to that the user-calibrated 8-LED metering and variable cutoff high-pass filter and you know that with the ISA Two you'll have everything you need to get the highest quality sound into your recordings.
Rupert Neve originally chose the Lundahl LL1538 to be the input transformer on the ISA 110. To this day the Lundahl transformer remains the best microphone input transformer available, and is used in every ISA Series mic pre. Rupert Neve also perfected the Zobel network found in the ISA circuit; something which takes a lot of knowledge and a golden set of ears.
ISA Two offers up to 80 dB of clean, distortion-free gain. The much heralded ISA topology also ensures low noise, even at the highest gain levels. The transformer alone supplies 20 dB of gain, while ISA's input stage offers up to 60 dB in addition, giving an astonishing 80 dB of maximum gain on the microphone input.
Four choices of input impedance, including the original ISA 110 value, allow you to match the preamp to your microphone, even if it's a vintage type, giving you the best possible sound. The impedance is selected using a switch on the front panel, and the impedance choice is remembered even once the unit is switched off and back on.
Each channel has an eight-LED array to clearly display the level of your two signal. You can line up your analogue levels with your converters of DAW by using the calibration knob on the rear panel. You will be safe in the knowledge that you have avoided clipping on the way in.
Two 1/4in. jack sockets on the front panel of ISA Two give you instant access to a transparent DI input. TRS line inputs are available on the rear panel too, and you can step through them instantly to select the one you want.
Built in, and easily accessed with its own large knob an illuminated button, is an extremely smooth sounding 18dB/octave high-pass filter of the same design as the original ISA 110 module. This is ideal for cutting out rumble, thumps and other unwanted low-frequency sounds and with a range of 16 to 420 Hz, it's easy to lose what you don't want, and keep what you do.
Each channel of ISA Two has its own balanced insert point. With 1/4in. TRS send and receive connections, your choice of signal processor can be connected and switched in and out using the illuminated switch on the front panel.
Focusrite's ISA Two brings together a totally independent pair of classic ISA microphone preamps from the original ISA 110 module, combining the best of traditional solid-state electronics with the original input transformer specified by Rupert Neve – the Lundahl LL1538. Each mic pre has the option of mic, line or the front-panel instrument input, with variable input impedance to ensure you are getting the best performance from the source. Up to 60dB of gain is available on the first four-position rotary and gain range switches, with a further +20dB of continuously variable trim, meaning a huge 80dB of gain is available should it be required. The high-pass filter features variable cut-off frequency between 16 and 420Hz. A pair of 8-segment LED meters show peak signal level in dBFS, while a rear-panel pot allows calibration to suit your A-D converters. Rear-panel insert points allow the use of inline processors such as compression.
The Focusrite Studio Console defined countless hits of the 80s and 90s, thanks in large part to its ISA 110 Equaliser and ISA 130 Dynamics Modules. Brainworx's bx_console Focusrite plug-in brings you stunningly accurate emulations of both in a single plug-in, perfectly capturing the famously warm, open sound of two of the most revered pieces of studio hardware ever made.
All Focusrite products are built to the highest standards, and are designed to provide many years of reliable performance.
| Preamp Type | Solid State |
|---|---|
| Number of Channels | 2 |
| Phantom Power | Yes |
| EQ |
16Hz-40HzVariable Highpass Filter |
| Phantom Power | Yes |
| Sample Rate |
Up to 192kHz |
| Bit Depth |
Up to 24-bit |
| Analog Inputs | 2 x XLR, 2 x TS (inst), 2 x TRS (line), 2 x TRS (Return) |
| Analog Outputs | 2 x XLR, 2 x TRS (Send) |
| Frequency Response |
10Hz-135kHz (±0.1dB) |
| Power Supply | Standard IEC AC cable |
| Width |
19" |
| Height |
1.75" |
| Depth | 11" |
| Weight | 8.16 lbs. |
| Manufacturer Part Number | AMS-ISA-2 815301005148 |
