The Radial Firefly begins with two inputs to allow quick changes on stage. This can be done using the front panel switch or with a standard latching remote foot-switch. The instrument signal is immediately routed to a tuner output that is always on. Following the award winning Radial JDV, the Firefly is also equipped with Drag Control load correction. This enables the artist to adjust the load on the magnetic pickup for a much more natural rendering. When bypassed, the load jumps to 4 meg-ohms enabling the Firefly to be used with piezo pickups.

The class-A circuit features a select 12AX7 tube drive with both gain and trim controls allowing the user to increase the grit and warmth as needed.