Pro Audio Review (October 2001)
By Jeff Severson
A tube direct box typically can add warmth to a guitar or bass plugged directly into a mixing board. During my testing, the Demeter VTDB-2B performed this duty well, and also proved to be useful for a variety of other applications and effects.
The Tube Direct Box ($600) is in a heavy-gauge, black-anodized case of brushed aluminum and steel. This sturdy package measures 8" x 5" x 2" and weighs in at four pounds. The unit features the standard direct box complement of two 1/4-inch jacks (input and tube buffered unity gain output, useful for driving long cable runs to amps, etc.) and an XLR output for connection to the mixer.
A Boost switch raises the gain of the tube circuit by 16 dB, useful for low-volume instruments. The unit also includes power and ground-lift switches, plus an easily accessed .5 Amp fuse housing. AC is provided to the unit via a permanently attached power cord. James Demeter designed this box with one 12AX7A tube and a Jensen JE-DB-E transformer.
I had the opportunity to use the Demeter DI on a variety of studio recording sessions and a few live performances. In all cases, the DI proved to be a reliable sonic asset to my sound.
Electric, bass and acoustic guitars all sounded a bit warmer and somewhat louder when played through this DI box compared to other standard studio (non-tube) DI boxes. Apart from the aforementioned warmth (probably more a function of natural tube compression than tone), I heard no undue coloration or loss of clarity.
The Boost switch came in handy for increasing the volume of my acoustic guitar's piezo pickup without adding any noticeable amount of noise. In fact, I found that many stringed instruments benefited from the more "driven" quality realized when the Boost switch was engaged.
I also ran a number of synthesizers through the Demeter on the way to tape. I found that normal input levels gave the synth sound warmth, and more gain took the sound to a slightly distorted level that remained musically friendly. The added punch of subtle distortion actually brought welcome life to the otherwise sterile synths.
With proper gain structure, the Demeter VTDB-2B provided clean, transparent direct sound, while intentionally hotter input levels brought on a musically pleasing distortion. The VTDB-2B quickly became the staple DI box for my studio and live performances, and the slight tube distortion when overdriven brought a little humanity to the sound of my digital recordings.
Jeff Severson is a recording engineer, demo producer and songwriter.