Basically, I'm going to describe now, briefly, the differences between passive electronics and active electronics. I'm going to show you these examples on basses. It can be applied to guitars. It's the same principle. Typically you'd find, say, an active system on an acoustic guitar or acoustic-electric guitar. It just means that there's a pre-amp built into it. There's a whole circuit dedicated to a pre-amp. It requires a battery. If you put that into an electric guitar or bass you're going to be dealing with higher output pickups because now you have an actual onboard system powering those pickups.
I have two examples. We have our 70s Precision bass, passive electronics. When you plug into an amplifier, you're now using... It's all the amp that's taking care of the output of the guitar. I'm going to switch to an active bass. You can see on the back of this Limbeck, this is the control area for your volume and tone and all the switching. This would be the battery compartment here. That's where the circuit is for the active pre-amp. This is the same volume setting, the same EQ setting as we had for the P bass.
You're basically hearing hotter pickups. You're hearing higher highs, lower lows. Everything is amplified before it gets to the amp. That's the pre-amp. You'll notice when you're battery needs changing it'll start to fuzz out. It won't be quite as loud. It won't sound as tight. The whole purpose of that is to have a tighter, louder sound which is why you would go for an active system in a bass or guitar.