DI-20 Stereo Passive Direct Box

Sometimes in studio and live sound work it’s necessary to plug instruments like electric guitars, electric bass guitars and keyboards directly into the mixing desk or recording interface.

A DI box performs the necessary level and impedance conversions so that the instrument can be connected directly to the microphone preamps of the desk or interface. In addition a DI box converts the unbalanced instrument signal to a balanced one, so long cable runs may be used without noise and interference.

The through jack is an output that presents a split or duplicate of the input signal. The most common application is connecting an electric guitar or bass guitar to both a mixing desk and an amplifier.

The instrument is connected to the input jack, the balanced XLR output is connected to the mixer or interface and the through jack is connected to the instrument amplifier.

When two audio devices are connected via an audio cable but connected to different power outlets, a “loop” is created between the ground in the audio cable and the ground in the electrical system. If current begins to flow in this loop a distinct 50Hz or 60Hz “humming” or “buzzing” sound can be injected into the audio path.

Eliminating this unwanted noise requires breaking the ground loop. The ground lift switch on the DI-10 and DI-20 disconnects pin 1 of the XLR output from the ground - safely breaking the ground loop.

No, both the Franklin DI boxes are passive, which means they require no power to operate. The level and impedance conversion is performed by a high quality transformer rather than active electronics. It is however completely safe to apply phantom power to the Franklin DI boxes.

Absolutely. The Franklin DI boxes have been designed with maximum headroom in mind. Our custom-wound FA-02 direct box transformer can handle massive amounts of level without distortion, and when pushed very very hard the small amount of harmonic distortion produced is very pleasing to the ear.

The first reason it may be preferable to use a stand-alone DI box over the high impedance instrument input on your interface is purely practical. If you wish to capture the direct sound of the instrument at the same time as an instrument amplifier, you need the “through” jack of the DI box to split the signal to the two destinations.

Secondly, if the instrument is to be performed a great distance from the mixing desk or recording system (such as on a stage or in a studio live room), using a long unbalanced cable from the instrument to the interface will likely result in unwanted noise and loss of tone. The DI box will balance the signal so that a long run of cable is no problem.

The third and more subjective reason is that much like microphones, DI boxes sound different to one another and you may prefer the sound of the Franklin DI to the one built into your interface!