Warm Audio DI boxes offer the rare versatility of having an onboard variable pad knob which attenuates your input signal all the way from -3dB to -30dB, which will easily tame any instrument input source. The Direct Box Active can also operate in "passive" mode.It includes a thru-put jack that is jumpered to the input jack. It is a convenience jack allowing you to send your instrument's signal to a second place in addition to the live mixer or recording device. This direct box can also take a recorded signal at line level and send it to another line input while simultaneously sending signal out of the XLR mic level output of the direct box.Connecting electronic instruments such as guitar, bass, keyboard, or drum machines directly to a PA or recording system. A DI box converts the high impedance, unbalanced output signals to low impedance, balanced output signals. By doing so, the instrument signals are now converted to the proper voltage level for the PA or recording system - which greatly reduces and/or eliminates connections which could cause tonal shifts and distortion.FeaturesPower: 48V phantom or 2 9V batteries. Can also be used passivelyConverts instruments to mic-level signals without signal degradationIdeal solution for plugging your instrument direct into any mic preCustom-wound Cinemag USA output transformerTop-quality class A components with gold-plated traces on circuit boardRugged aluminum constructionPad: variable from -3 TO -30DBBalanced output: 600 OHMS, mic levelInput impedance: 1 MEG OHMSTHD: .01% from 20HZ to 50HZ. less than .003% from 50HZ TO 20KHZFrequency response: 10HZ TO 90KHZ +/- 0.5DB Warm Audio WA-DI-A Direct Box Active.