Focusrite ISA One Desktop Microphone Preamp

93 out of 100. Incorporating 300+ ratings and reviews.

Gearank Recommendation

The Focusrite ISA One was on our recommended list for Microphone Preamps from March 2021 until it was out-ranked by the Grace Design m101 in September 2022.


Originally introduced in the late 2000s, the The ISA One design was based on the original ISA 110 topology with a Lundahl L1538 transformer and Zobel network.

The ISA One takes the sound of their lauded Forte console into a desktop preamp form factor.

It features a mic / line / instrument input selector and an impedance selector to match whatever mics you plan to use. It also includes insert send/return, cue mix, and headphone out for latency free monitoring,

If you’re looking for a golden ticket to hang with the big rigs, the ISA One is one that’s within reach. Many users have experienced a big jump in their recording quality with the ISA One while some with already fantastic rigs felt barely an increment. If you’re one of the latter and want to take that big step up towards harmonically richer raw tracks, get it.


  • Channels: 1
  • Mic Preamps: Grace Design preamp with Ribbon Mic mode
  • Input Connectors: 1 x XLR, 1 x 1/4″ (Hi-Z)
  • Output Connectors: 1 x XLR, 1 x 1/4″ (Balanced), 1 x 1/4″ (Unbalanced)
  • Controls: Knobs: Gain, Trim | Buttons: 48V Phantom Power, Ribbon Mode, HPF, Power
  • Dimensions: 1.7″ x 9″ x 8.5″
  • Weight: 2.4 lbs.
Although this was previously on our recommended list, there are now options with higher ratings in our guide to The Best Microphone Preamps