ISA One is part of Focusrite's classic lineage of no-compromise microphone preamps. The original ISA modules, commissioned by Sir George Martin for use in AIR studios, are time-honored and coveted by engineers the world over. Literally hundreds of hit recordings have been made with Focusrite's ISA range--a legacy that continues today. ISA One uses the famous Lundahl input transformer--essentially the same circuit, based on the original ISA110, that has been used for 30 years in successive Focusrite designs. The input transformer imparts a special character to the sound that can't be truly emulated in any other way. But this mic pre has a twist the original didn't have, which makes it far more versatile: four carefully-selected impedances allow you to match microphone to input in different ways. Optional stereo 192kHz A-D converter: upgrade with an optional digital card that delivers the best A-D performance in its class, with a dynamic range of 118dB Switchable Impedance: four input impedances that help shape your sound, including that of the original ISA 110 Dedicated insert point: allows you to place Extra processing between the Preamplifier or DI and the optional converter, such as an EQ or compressor. Focusrite now offers a 3-Year Warranty on this and all other Focusrite products.