Focusrite ISA One Microphone Preamp.

The ISA One microphone preamplifier delivers Focusrite's prestigious ISA transformer-based preamp in a rugged and portable chassis, at a groundbreaking price.

ISA One features the classic vintage microphone preamplifier topology from the original ISA110 module, which formed the cornerstone of each channel of Focusrite's legendary Forté console.

The preamp is complemented by a line input and an independent D.I. channel, complete with dedicated gain control, active or passive impedance switch, a TRS Jack output for routing to an amp and an independent XLR output on the rear. This flexible independent D.I. makes the ISA One ideal both for engineers wishing to blend a D.I.’d guitar signal with a mic’d guitar cabinet, and for demanding performers who require a single classic solution for both guitar and vocals.

A variable impedance circuit has been added, allowing the user to switch between four carefully selected input impedance settings. In addition to the original ISA110 impedance, three further impedance settings allow perfect matching, or creative mismatching of the preamp with any microphone. ISA One also features an insert point, should the need arise to place extra processing between the preamp or D.I. and the optional converter. Phantom power, phase reverse and a 75Hz, 18dB/octave high-pass filter are also available from the angled front fascia.

Independent input metering for both channels is provided in the form of a moving coil VU meter with variable calibration to suit analogue and digital recording media, alongside two six-LED peak meters; inputs can be metered either pre- or post-insert. The meter calibrations utilise all the same reference points as Avid's Pro Tools HD system, allowing effortless line-up.

ISA One’s headphone output features a dedicated volume control, which delivers an external stereo cue mix (a simple click track or a stereo mix feed from an interface or a live console) fed to the headphones via two TRS jack inputs on the rear of the unit.

An optional state-of-the-art stereo A-D converter is also available (the same card as used with the ISA430 MkII).

Features

• ISA series transformer-based preamplifier
• Flexible independent D.I. channel
• Switchable impedance
• Headphone output with volume control
• Dedicated insert point
• Optional stereo 192kHz A-D converter