The ISA preamp range has graced professional recording facilities the world over – but this classy single-channel model is within reach of the home and project studio.
The ISA preamp design, which has long been one of the jewels in the Focusrite crown, can be traced back to the original Rupert Neve circuit developed for the ISA 110 module. The design was commissioned for the famous AIR studios and combined a transformer-coupled mic/line preamp with a classic Neve equaliser. So successful was the ISA 110 circuit that it was to provide the basis for the Focusrite Forte Studio Console, and more recently it was re-engineered as a single-channel 1U rackmount device.
Today, the pro studio market continues to shrink while the private studio market goes on expanding, leaving companies like Focusrite with the challenge of creating high-end products that are within the budget of a typical project studio owner. The company already manufactures the Platinum series of processors for those who need something quite cost-effective, but it would be madness to try to build a Platinum version of an ISA unit — the component cost alone would render it impossible. A more practical answer is to break the high-end products down into separate blocks, and that’s the approach taken in the ISA One.
The Focusrite ISA One is a single channel microphone preamp in a compact desktop format. It is a descendant of the preamps found in the legendary Focusrite Studio Console designed in the 1980’s for The Beatles’ producer, Sir George Martin.
ISA stands for “input signal amplifier” and that’s exactly what you get here: There’s no equalization or compression — just a versatile input stage for microphone and direct input that can be used simultaneously. The ISA One boasts a Lundahl LL1538 input transformer as well as a good deal of input and output flexibility.
Because you can use both the mic and DI inputs at the same time, and with two separate outputs, I’m not sure if “single channel” is the best description. Maybe it’s better to think of it as “a channel and a half”.
The unit I reviewed was fitted with the optional digital output card, adding on 2 channels of D/A conversion.