Jensen Transformers JIK-DB1 Iso-Kit

The Jensen JIK-DB1 Iso-Kit comes with easy-to-assemble instructions, quality components, and a printed circuit board with extra large gold-plated solder points that makes it easier for students who may be new to soldering.

- JIK-DB1 Iso-Kit Under Construction--  Mouse Over To Pause--iPad and Smart Phone Refresh--

Once built the JIK-DB1 Iso-Kit's circuit board with its Jensen transformer is attached to a metal tray that slides into a one-piece "crush-proof" aluminum extruded cabinet. I found the JIK-DB1 to be a rugged and solid unit that does not easily slide around the floor where DI boxes are often found.

When properly assembled, the JIK-DB1 direct box is capable of a frequency response of 10Hz to 50kHz with undetectable phase shift, and low noise particularly in the 50Hz to 60Hz range where possible interference from AC power lines can dominate. This noise has always been the bane of recording/live sound engineers. I found the ground switch to take care of any noise usually associated when connecting guitars (and their amp's ground) to studio's equipment (and their different ground).

Educational Video

I built the JIK-DB1 Iso-Kit easily in about an hour using only the recommended tools and instructions and it worked perfectly the first time.

As an important teaching adjunct to both students and instructors or for any one building the kit is the 13-minute video instruction at www.jensen-transformers.com/iso-kit-video/. It's great! But there are also printed instructions included and, under supervision of your teacher, beginning electronic students with little experience will build and finish a quality direct box that will sound great, work trouble-free and last for years!

I liked that the Iso-Kit includes a 15dB input pad for attenuating hot signals from keyboards, synths and guitars/basses with active electronics. These hot signals can overload microphone pre-amps and possibly the JT-DB-EPC transformer itself. The transformer reduces incoming signal by 22dB and, in my testing with guitars and basses, most of the time the pad was not required. I also thought the 180-degree phase flip (polarity) and ground lift switches all worked flawlessly. Whenever no sound is passing through the unit, you can freely switch them without producing a loud "pop."

As Re-Amp Too!

Using both its 15dB pad plus my own inline XLR pad (T-pad) I also tried the JIK-DB1 connected backwards as a re-amp device for playing already-recorded audio out of Pro Tools back through my guitar amp. One of the cool things about passive transformer DI boxes is that most will work in a pinch, as a basic re-amp interface.

Connect a (greatly) attenuated bus send (output) signal from Pro Tools to the JIK-DB1's XLR connector and then run a 1/4-inch guitar cable from the unit's Loop Out jack back to your guitar amp's input jack. Engage the 15dB pad so that the front end of you guitar amp is receiving a reduced level. My recommended XLR inline T-pad is an optional refinement, but you can go without one; but it makes setting a send level from Pro Tools very touchy and you risk overdriving the DB1's transformer. Not good!

As Speaker Direct Too!

You could also use the JIK-DB1 connected to the extension speaker jack of a guitar amp provided it was a low power amp and there is a speaker (load) connected as well. You'll get all the grit and color of your amp that way. However, be careful connecting to the speaker output of a vacuum tube amp unless its speaker or a properly designed cabinet simulator/load device is also connected. Awesome!

So I am highly recommending building the very useful Jensen JIK-DB1 Iso-Kit--especially to students and schools who teach audio engineering and electronic classes. It comes with a good explanation of what a direct box does, how this particular circuit works, and when, where and why the ground switch and 15dB pad are necessary.