Do I need a DI?

[gmfgtr]

simondylan is right about the PADI being an Ultrasound product. These are currently called the DI+. Name was changed because of the PADI name confusion with the Baggs unit

[Aaron Smith]

Louis got this exactly right- this should be stickied to the top of the page. These threads come up every so often, and they usually have more misinformation than good information.

Originally Posted by lschwart

Please, to be clear: the purpose of a preamp is to make a signal louder near the source. The purpose of a DI box, whether active or passive, is to lower the impedance and balance a high impedance, unbalanced signal so it can be sent through a cable longer than 15 or 20 feet into the microphone (XLR) input of a mixer.

Yes, these functions are often combined in units called, confusingly both "preamps" and "DIs," but they are separate functions.

So: if you are sending a signal from a pickup like the K&K, which puts out a relatively high impedance, unbalanced signal through a regular 1/4" instrument cable, you only need a DI if you need to send that signal down a long cable to the XLR input of a mixer or snake, OR if the input impedance of the regular 1/4" input on your combo amp has too low an impedance to deal with the K&K signal. In that case you might use a DI box and go into the XLR input of the amp (especially if you have to stand more than 15-20 feet away from the amp). Or you might use some other device (a preamp, an effects or EQ pedal) to lower the impedance to go into that 1/4" input. In some cases, but not with the K&K, the pickup signal is also too weak for the preamp of the amp to handle without adding a lot of extra noise. In that case, a preamp nearer to the guitar might be desirable for going even into the 1/4" input of the amp.

I'm reasonably certain that the 1/4" inputs on all the Fishman Loudboxes have a high enough impedance to handle the signal from a passive K&K. If you want a preamp nearer to the pickup itself to reduce noise, or a unit that includes EQ you like better than the EQ on the amp, then look at one of the many "swiss army knife" units out there: The L.R. Baggs PADI or Venue, the Radial PZ-Pre or Deluxe, the simpler Red-Eye, etc., and etc.. Note that the Loudboxes also have their own DI function and will take a passive signal from a pickup like a K&K, put it though a preamp, balance it and reduce the impedance, and then send it along an XLR cable to a mixer, either directly or after also putting it through some EQ and/or effects.

Louis