Jensen JT-DB-E passive DI wiring
¼″ instrument in · ¼″ thru to amp · balanced XLR mic-level out · 12:1 step-down · ground lift on pin 1
Lead chart
| Lead | Function | Connects to |
|---|---|---|
| Yellow | Primary + (start) | ¼″ tip |
| Black | Primary − | ¼″ sleeve |
| Orange | Primary-side shield / case | ¼″ input sleeve |
| White | Primary-side shield / case | ¼″ input sleeve |
| Red | Secondary + (in phase with yellow) | XLR pin 2 |
| Brown | Secondary − | XLR pin 3 |
| Gray | Secondary Faraday shield | XLR pin 1 (lift switch to chassis) |
Build notes
Black, orange and white all land on the input jack's sleeve, which is bonded to the enclosure. Gray is the only ground lead on the output side: it goes to XLR pin 1, and pin 1 reaches the chassis only through the ground-lift switch. Opening the switch breaks the loop between your instrument rig and the console.
The thru jack is wired straight across the input, tip to tip and sleeve to sleeve, so the amp gets the untouched instrument signal while the transformer listens in parallel. The amp shares the input-side ground, and the lift switch still isolates the console from both.
Yellow-to-tip and red-to-pin 2 keep the output in polarity with the input. Swap red and brown if you want a polarity-reverse switch (DPDT across pins 2 and 3).
Before soldering, check with a meter: yellow–black reads much higher resistance than red–brown, and none of the shield or case leads should show continuity to any winding. Sleeve the 30 AWG leads and keep them short and dressed away from the jacks.
