Features: The features on the Firefly were made with the working musician in mind. Connected to the input is a drag control that allows the user to adjust the load on the pickup of the instrument connected to it, making all pickup types sound great through the DI. The Firefly sports two individual inputs with individual volume controls, so that when connect multiple instruments (acoustic bass and electric bass for example) and match the volume send of each instrument to the stage and PA. The two inputs are switchable (and the entire signal mutable) via optional footswitch. A master volume knob controls the overall output of the direct box and an effects loop allows the use of effects with both inputs of the Firefly.
Another brilliant feature of the Firefly is the always-on tuner out. Buffered and electronically isolated, this output removes the tuner from the signal chain between your instrument and the DI, providing the purest sound from instrument to amplifier. Because the tuner out is also before the tube stage of the DI, it can also serve as a direct “clean” ¼” out if you want to bypass the tube. The feature I found to be the most innovative and useful is the high-pass filter. A rotary knob on the front panel allows the user to cut unneeded lows to make instruments such as acoustic guitars or mandolins cut through the mix without feeding back.
The output section of the Firefly is fairly straightforward: a standard XLR output is accompanied by an Aux ¼” output that utilizes the same signal path as the XLR. A “Thru” output is switchable to pre and post tube section, to provide yet another flexible output option. Recessed buttons on the rear of the DI control phase reverse and ground lift connected to the XLR output. The Firefly is powered with an external power supply that securely locks to the Firefly via a 4-pin XLR connection.
Sound: Simply put, the Firefly sounds unreal. In my review, I tried every instrument I had available: acoustic guitars, electric bass, acoustic bass, farfisa organ, analog synths, digital synths, mandolin, Fender Rhodes, and a Wurlitzer 200A. I could not find anything that the Firefly didn’t make sound amazing! The overall sound of the box was silky smooth and warm with a full body and amazing clarity. The firefly made digital emulated keys sound incredibly close to the real thing. Acoustics sounded full and round no matter what pickup system they used. The tube took away all the harsh digital high end of the synths and gave them a smooth saturation that made everything sound really natural. Everything sounded amazing, but the highlight was electric bass. The drive from the tube was so warm, natural, and smooth I could barely believe I was plugging in straight to a direct box! I had absolutely no noise issues at all when plugging in direct, into studio preamps, or even vintage amps. The Firefly made my instruments sound better than I’ve ever heard them sound.
Value: Overall, the Firefly is the best-sounding direct box I’ve ever heard, and quite possibly one of the best tube preamps I’ve used. The drag control, high-pass filter, and flexible routing are all musician-friendly and easy to use. The only feature I miss about the Firefly is a stereo option, for keyboards and stereo synths. The relatively high price for a direct box ($599.99) may drive some away from the Firefly, but in my opinion, the Firefly is moderately priced for all its features paired with the unmatched sound quality. The features, the craftsmanship quality, and most importantly the sound, make the Firefly hands down the best tube DI box I’ve ever used.