What's the difference between active and passive pickups?

Passive pickups are the traditional, simple design — magnet, coil, wire, done. Active pickups add a battery-powered preamp into the mix, and that one addition changes more than people expect.

Passive

No power required, no battery to die at the worst possible moment, and a signal that's shaped almost entirely by the pickup's own coil winding, magnet strength, and construction. Passive pickups produce a lower output signal that's more dynamically responsive to how hard you pick or strum — dig in and you get more output and grit, play softly and you get a cleaner, quieter signal, all without any circuitry intervening.

Active

A built-in preamp (powered by a battery, usually 9V) boosts the signal right at the source, before it travels down the cable, which gives a hotter, more consistent output with a lower noise floor — genuinely useful for high-gain applications where a noisy signal gets amplified along with everything else. Active pickups often use smaller, weaker magnets than passive designs since the preamp is doing the heavy lifting on output level, which can actually reduce unwanted magnetic pull on the strings.

The tradeoffs

Active pickups need a battery, and a dead battery means a dead (or drastically weakened) guitar signal, mid-gig, with zero warning beyond maybe a slight dulling right before it goes. Passive pickups have no such failure mode. Tonally, active pickups tend toward a more compressed, consistent, high-output character (popular in metal and high-gain genres for a reason), while passive pickups retain more dynamic range and a wider variety of classic tonal character across genres.

Which should you choose?

Depends entirely on genre and what you value — dynamic responsiveness and no battery anxiety, versus consistent high output and lower noise at higher gain. Neither is objectively better; they're built for different jobs.