DiVision Vacuum Tube Direct Box

The DiVision is a limited edition nuvistor vacuum tube powered direct box with an LBA-MC15 audio transformer. It's powered by a standard 9V DC pedal adapter (350mA) and steps it up internally to 230V DC for loads of headroom and big tube tone. Control knobs are input "volume" and "Vision," which is a tube-powered high frequency shelving boost. Buttons are phase invert and ground lift, as seen on the TI Box. Jacks are 1/4" input and bypass, and XLR mic-level balanced output. Power connection is a standard Boss-style barrel jack.

This design utilizes a single 6DS4 nuvistor vacuum tube running at 230V. I wanted to balance tube life with great tone and low heat. Great tone doesn't usually balance well with low heat and long tube life IMO, but I found a zone where it balances out nicely. The onboard power supply is designed to be efficient and low noise in order to generate the 230V B+ and 6V filament voltages with minimal heat dissipation. The entire unit gets warm during use, but never hot. I'm running the tube's filament a little below its rating of 6.3V since it has no effect on performance, but the lower voltage does extend filament life substantially.

The volume control allows the user to attenuate loud signals before they hit the output transformer, should that be desired (for greater clarity). The vision knob is an adaptation of the "Brilliance" circuit used in my Trinity channel strip's EQ. Its a high frequency shelving boost, which provides up to 6dB of boost shouldering at around 10kHz. This control is an active EQ circuit, which is powered directly from the nuvistor. Tube EQ!

The LBA-MC15 audio transformer is the output transformer of the DiVision. It's the same transformer used in the TI Box. If you're not already aware, I make these in-house.

Technical Specs

• 11dB signal boost (adjustable via "Volume" knob).
• 6dB HF shelving boost at 10kHz (Adjustable via "Vision" knob).
• flat from 10Hz-22kHz +/- 2dB
• Input impedance ~700k Ohms
• Output impedance = 200 Ohms
• Input power = 9V DC @ 310mA minimum. Power supply with 350mA or greater capacity recommended.
• THD+N = 0.2%