The Firefly from Radial Engineering is a single-channel active direct box that features a Class-A front end, and a 12AX7 tube stage to add warmth. A variable low-cut knob enables you to optimize the sound of a variety of instruments, such as electric and acoustic basses, electric and acoustic guitars, mandolins, viola, and more. The Firefly features two 1/4" Hi-Z inputs with independent Trim knobs, and it's possible to connect both active and passive instruments. A "Drag Control" terminal gives you the ability to adjust the load correction so you can get the best tone from a magnetic pickups.