Active di units an active di unit contains a preamplifier.
Active di box with active pickups.
This means that it can handle lower level signals and still sound good.
And vice versa the astounding headroom of a transformer when driven by an active system typically higher levels.
And active dis can be designed to be extremely quiet hi fi and transparent tonally.
These days there are excellent passive and active di boxes.
Direct box passive is best for balancing the signal of instruments with active electronics but still performs extremely well on passive pickups by producing a frequency range that exceeds the bandwidth of most passive di boxes on the market.
The direct box active can also operate in passive mode.
The circuitry onboard active dis requires power which can come via batteries dedicated power supplies.
Generally speaking an active di gives you more signal and that means an extended high end.
If you use active pickups you might want to audition them first.
For example if you were using a passive di to send an old fender bass to the console its single coil pickup had to drive amp transformer mic splitter transformer and a few hundred feet of cable.
Active direct boxes are in fact preamplifiers whose primary function is to provide higher input impedance than that of a transformer to drive instruments with low level signals.
On top of all this this active di box can be powered with phantom power a separate adapter or a 9v battery.
An active box clears this up with higher impedance inputs.
Direct box active is best for instruments with passive pickups especially acoustic instruments.
The pz di is a high performance specialized active direct box designed to accommodate acoustic and orchestral instruments with a selectable input impedance that can accommodate magnetic pickups or piezo transducers and a variable low cut filter.
I have a guitar with active pickups that makes a lot of active dis splat the out pad engaged or not.
The reasoning is the frequency alteration of a transformer load on a passive pickup.
Active di units require a power source via batteries or a standard ac outlet connection and may contain the option for phantom power use.
An active instrument could clip an active di in some cases.
Some people claim to prefer the para driver difor bass though it s more focused on.