Original Article by FMIC
Modified and updated. These things get lost and I liked this version.
PASSIVE ELECTRONICS
- The simplest, most common electronics design
- No onboard amplification circuitry inside the guitar or bass
- No Battery
- Passive electronics can only subtract elements from a signal
- Passive electronics CAN adjust the output curve of pickups -Bruce
The pickups on passive guitars and basses consist at the most basic level of a magnet wrapped in coils of wire. In the magnetic field produced by this design, a vibrating string produces a weak electrical signal. This signal can be modified by caps and resistors. This weak signal is sent through your instrument cable to your amp, which is where all the signal boosting happens.
ACTIVE ELECTRONICS
- Active guitars and basses have their own onboard amplification circuitry
- Require a Battery (or some kind of rechargable power supply)
- Can both subtract and add elements to a signal including EQ, filtering, and feedback control
- Less susceptible to electrical interference than passive electronics (Typically use IC OP Amp style circuits that have common mode rejection) -Bruce
- Active instruments have their own onboard power source—usually a preamp powered by 9-volt battery or (2) 9-Volt batteries for 18V – Bruce
- Generally more expensive than passive instruments
Active circuitry is especially popular for bass guitars, making them brighter, clearer and snappier, which is ideal for slap-and-pop playing. Active pickups are also popular on high-performance guitars often used by metal players. Fender currently offers several active guitars and basses, including the Deluxe Active Jazz Bass and Deluxe Active Jazz Bass V, and the Jim Root Stratocaster, Telecaster and Jazzmaster.
It’s important to note that an active instrument will not work at all if its onboard power supply has been exhausted; it will not continue to work in a passive manner. However, some designs allow bypassing of the active electronics if there is no power available.. -Bruce