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Radial Engineering Announces The New Firefly Tube Direct Box

By PSW Staff January 24, 2012

The new Firefly tube direct box

Radial Engineering has introduced the Firefly tube direct box, a fully discrete class-A unity gain amplifier designed for both studio and live performance.

Radial company president Peter Janis explains: “We have always wanted to launch a tube DI to round out our product range. But over the past two years, we have been sidetracked as we developed the Workhorse and our many 500 series modules. We finally got back on this project and are pleased to bring the Firefly DI to market.”

The Firefly begins with two inputs, each of which features a separate level control to enable the artist to set each instrument with optimal gain.

Switching between inputs can be can be done using the front panel switch or via the optional JR2 remote footswitch. The instrument signal is immediately routed to a tuner output that is always on.

When used with the JR2 footswitch, the Firefly may also be muted remotely for quiet on-stage tuning. Both the footswitch and front panel are equipped with LED indicators for status monitoring.

Following the Radial JDV, the Firefly’s front end circuit is 100 percent discrete class-A and is void of any circuit stabilizing negative feedback. This produces a more open, less constricted sound. 

The Firefly is also equipped with Drag Control load correction that 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 such as common with upright bass and other acoustic instruments.

The exceptional warmth and detail is achieved by combining Radial’s unique front end with an all new12AX7 tube drive circuit. Contrasting the input sensitivity with the output drive enables the artist to fine tune the grit or edge to give the sound more character. 

Firefly comes shipps with two 12AX7 tubes, a select premium tube for audiophile performance and a low-fi version for added growl.

A fully variable high-pass filter enables the engineer to set the bass cut-off frequency for optimal layering. This ‘Nashville trick’ lets you set the cut-off to better match the size of the instrument whereby a lower cut-off would be used on contrabass, slightly higher on acoustic and higher again on fiddle or mandolin. By setting a different cut-off for each instrument one can eliminate resonance while still retaining the character.

Connectivity is extensive: The rear panel begins with two stacked 1/4-inch instrument inputs. A second set of stacked 1/4-inch jacks presents the user with a buffered thru-put that delivers either the original instrument’s tone or the output from the tube circuit.

Below, an insert jack enables one to add in effects in series with the tube drive circuit and apply the effects to the overall sound.

The third set of stacked jacks feature a tuner output and a TRS jack for the JR2 remote control. The Radial transformer coupled XLR output is outfitted with a ground lift switch and a 180-degree polarity reverse. This can be helpful when controlling feedback or interfacing with older vintage gear.

Power is supplied via an exterior switching supply for 100- to 240-volt operation and delivers a variable output that ranges from a typical unity gain DI level to a full +4 dB line level for direct recording.

The Firefly is road ready with 14 gauge steel construction plus a protective zone around the controls and switches. This is augmented with steel cased switches and potentiometers plus a double sided military grade PCB for added life.

The Firefly comes with a carry handle that may be removed should rack mounting be needed for touring using optional rack-mount kits.

Radial Engineering


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