Mystery Magicians RBDI Tube Instrument Preamp and Re-Amper Direct Box

The Mystery Magicians RBDI is a fully tube-based, Class A direct box and instrument preamp that delivers classic tube tone for tracking, reamping, and tone shaping. It features all tube circuit, giving natural harmonic richness, fast transient response, and ample headroom. Unlike starved plated designs, it runs 12AU7 tubes at a robust 320V, ensuring full Class A performance. The RBDI is a slim 1U rack unit that fits neatly with your studio or stage gear. It comes supplied with an auto line detecting power supply for plug and play operation anywhere in the world.

HI Z INPUT FOR ALL PICKUP TYPES

The Hi Z input handles passive and active pickups. The switchable HIGH/LOW Gain front end sets the sensitivity by tapping either the full first dual triode stage (high gain) or the second half (low gain). Input and Output Gain controls let you drive the tube stages from clean headroom to rich, controlled saturation.

ONBOARD TONE-SHAPING

A true bypassable three band tube EQ gives precise tonal control. Bass can be cut or boosted by 15dB, middle by 6dB, and treble by 10dB. The Bright switch is a position dependent preset tied directly to the Input Gain control. At lower gain settings, where human hearing naturally loses high frequency perception, the Bright circuit boosts high frequencies and gently rolls off the low end to maintain clarity and presence. As input gain is increased, the Bright effect progressively tapers off, preventing harshness and keeping the tone balanced at higher levels. Using the Bright switch with the EQ lets you simultaneously boost and cut certain frequencies, somewhat enabling the Pultec (boost while cut) trick and a wide range of tonal options.

DEDICATED REAMP INPUT

The dedicated reamp input accepts line level signals, allowing prerecorded tracks or stems to run through the tube circuitry for tonal enhancement and harmonic enrichment. Flat, sterile, or poorly captured stems can be recolored, equalized, and reshaped using the tube gain stage. The result is added harmonic density, controlled dynamics, and tonal depth that is difficult to achieve with plugins alone. The RBDI adds a front panel REAMP/NORMAL switch, letting you quickly flip between the rear XLR Reamp Input and the front Hi Z Input, making it easy to switch sources on the fly.

DI, PREAMP, TONE SHAPING, AND REAMPER IN ONE PACKAGE

With up to 53 dB of maximum gain, the unit provides sufficient clean gain to properly drive high impedance microphones with 1/4" outputs, such as harmonica microphones, without the need for an external booster or transformer. This allows the RBDI to function effectively as a dedicated harmonica preamp. Designed for guitar, bass, synths, keys, and other Hi Z sources, the RBDI combines DI, preamp, tone shaping, and reamp capabilities in a single all tube package. It delivers hands-on control, authentic Class A tube character, and flexible tonal options.

MYSTERY MAGICIANS RBDI FEATURES:

• Fully tube-based, Class A 19" rack-mount direct box and instrument preamp
• Classic tube tone for tracking, reamping, and tone shaping
• Hand-wound output transformers built in house
• Phillips ECG 12AU7 NOS tubes
• WIMA, Panasonic, and TRW audio grade capacitors
• Metal film resistors
• Japanese TOCOS sealed potentiometers for smooth, long lasting control
• Omron audio grade relays for all signal switching
• Custom designed and CNC machined anodized aluminum knobs
• Dual tone hammertone powder coated steel chassis
• Phase switch for phase reversal
• Ground lift switch to eliminate ground loops
• Front Thru connection for tuners, amps, or parallel processing
-20 dB balanced output pad to safely manage interface levels while pushing the tube stages hard