Behringer ULTRA-DI PRO DI4000 Active DI Box

Behringer ULTRA-DI PRO DI4000 Active DI Box

The Behringer ULTRA-DI PRO DI4000 is a four-channel active direct injection box in a 1U rackmount format, built to connect instruments and other unbalanced sources to mixers and amplifiers with correct impedance and level matching. Each of its four identical channels converts an incoming signal to a transformer-balanced, mic-level output using a Behringer OT-1 transformer, helping long cable runs stay quiet and free of interference. The DI4000 also accepts very strong signals, including direct connection to speaker outputs rated up to 3,000 watts with the appropriate attenuation, and it can add 20 dB of gain to lift weak sources. For studios and live rigs that repeatedly need several clean DI channels in one rack space, it replaces a row of separate single boxes.

Key features

• Four independent active DI channels in a 19-inch, 1U rackmount unit
• OT-1 transformers for a flat frequency response and transformer-balanced XLR outputs
• Direct connection to speaker outputs up to 3,000 W with switchable input attenuation
• 20 dB gain switch for pre-amplification of low-level signals
• Phase reverse and switchable 8 kHz high-cut filter per channel for problem solving and guitar use
• Ground lift switch to eliminate ground-loop hum, with an 8-segment LED level meter per channel
• Jack and gold-plated XLR connectors, illuminated switches and an internal switch-mode power supply

Four channels of impedance and level matching

A DI box solves a basic mismatch: instruments and many electronic sources are unbalanced and high-impedance, while mixer microphone inputs expect a balanced, low-impedance signal. The DI4000 inputs accept XLR and quarter-inch connections with an input impedance of 220 kilohms with the pad out, and the maximum input level reaches plus 20, plus 40 or plus 60 dBu depending on attenuation settings. Outputs are transformer-balanced on XLR with a 600 ohm impedance and a maximum output level of plus 20 dBu. Link outputs pass the input signal onward, so a bass or guitar can feed both the mixer through the DI path and a stage amplifier at the same time, preserving the performer’s normal monitoring setup.

Handling loud sources and quiet sources

Switchable attenuation is what allows the same channel to accept a delicate low-output instrument and, at the other extreme, a speaker-level signal from an amplifier output. Behringer rates that speaker connection capability at up to 3,000 watts, which makes the DI4000 useful for capturing an amplifier’s output character without a microphone, provided levels are set carefully and the correct pads are engaged before connecting. In the opposite direction, the plus 20 dB gain switch pre-amplifies low-level signals so they arrive at the mixer at a healthy level rather than buried in noise. The per-channel LED meter, with eight segments, gives a quick visual check that each source sits in a sensible range.

Tone and troubleshooting tools

The switchable high-cut filter at 8 kHz is intended for guitar applications, taming excessive top-end harshness from direct signals and speaker-output feeds. Phase reverse corrects polarity problems instantly, for example when a DI signal is combined with a microphone on the same amplifier and the two paths interact. Ground lift separates input and output grounding to break the hum loops that commonly appear when instruments, amplifiers and mixers share a stage. System figures underline the clean design intent: bandwidth extends to 60 kHz into a 100 kilohm load, noise is rated at -90 dBu, distortion at 0.01 percent at 1 kHz and crosstalk at -100 dBu. Illuminated switches keep the channel state readable in dark stage and rack environments.

Rack use in studio and live rigs

The internal switch-mode power supply accepts 100 to 240 volts, draws 10 watts and connects with a standard IEC cable, so the unit travels between venues and countries without an external adapter. At 483 mm wide and 2.1 kg, it occupies a single rack unit alongside patchbays, preamps or wireless receivers. Typical uses include multiple keyboards on a live stage, bass and guitars in the studio, electronic drum modules, and any setup where several unbalanced sources must reach a mixer over long, interference-prone cable runs. By keeping four complete DI channels, each with gain, attenuation, filtering, phase and ground controls, in one powered rack unit, the DI4000 reduces setup time and removes a common source of hum and level problems before the mix even begins.