Quote:
Originally Posted by Mike_A
im not sure if this is always true, but from my experience passive pickups also have high impedance whereas active pickups have lower impedance. this is important because a high impedance passive pickup sounds really tinny when plugged into an input jack that can not handle high impedance or high Z. most mixing board line-ins will require a preamp or DI in between. whereas, an active pickup with its low "Z" you can plug in just about anywhere.
to the experts, please cmiiw...thanks
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Piezo pickup elements, which includes everything from undersaddle pickups like the Baggs Element or the Fishman Matrix, and most SBTs such as K&Ks, Trance, etc all need to go into a high impedance. That's the *raw* pickup element - they're inherently high impedance. But with an active system, the manufacturer adds an onboard preamp that provides that expected high impedance input for the raw pickup, so the pickup element itself is "happy" :-).
The impact of impedance on a raw pickup element can be substantial, depending on many factors. But in active systems, you are buffered from that impact by the onboard preamp. Many active systems can be plugged into at least relatively lower input impedances, tho most acoustic amps and preamps offer 1M or more, so it's kind of a moot point. There are some systems, such as Taylor's balanced ES1 system, or Trance's Amulet M Phantom, specifically designed to go into a very low input impedance, like a mixer's mic input. So you sort of have to understand the specific system to know for sure. But it's reasonable to just always plug any guitar into a high impedance input, and good signal hygiene is to use a DI when plugging directly into any mixer.
BTW, AGF seems to talk about passive pickups a bit disproportionately. They're pretty rare in the grand scheme of things. I don't know of a manufacturer who ships a built-in system that is passive, for example. Probably 99% of pickups out there are active (wild guess, but it's "most" for sure). It's only among those of us who install after-market pickups (rare) that passive even comes up. There are only a handful of passive acoustic pickups. Most people don't have to worry about impedance matching, etc, etc, because the manufacturer has already dealt with the issue.