Both types have devoted fans, but what is the difference between active and passive pickup types?
Remarkably, guitars have been built with pickups for well over 60 years. This neat device enabled the development of the solid bodied electric guitar, and provided it with its unique voice.
Over the years, the pickup has evolved and diverged into many different varieties. Most notably, the two main groups of single coil and humbucker (twin coil) pickups have appeared.
More recently, active pickups have emerged. This raises the question, what is the difference between active and passive pickups?
The original magnetic guitar pickup was a passive design. Essentially, these are simple transducers, built by wrapping many coils of copper wire around a permanent magnet, usually made of Alnico or Ceramic.
The location of the magnet in proximity to the strings causes the strings to magnetise, and become magnets, too. Because of this, when the strings move, they disturb the magnet field, and cause an electrical current to pass through the copper wire.
Active pickups still use coils of wire, like their passive counterparts. However, they use far fewer coils. Instead, their circuitry incorporates an active preamp (usually powered by a 9V battery) to boost the signal level, filters and EQ.
Advantages and disadvantages
So, why would you use a powered circuit when you could use a passive one?
Well, the problem with passive pickups is that the many coils of wire involved can transmit a lot of hum and background interference (this was the main reason that humbuckers were developed). In addition, the magnets used in passive strings can pull them inwards, and occasionally cause intonation issues. Passive pickups are also pretty sensitive to feedback, when pushed hard.
The lower number of coils on an active pickup means that they have a lower natural output (i.e. before the pre-amp), are less susceptible to background noise, and are naturally much quieter in this regard. However, the active pre-amp means that these pickups generally have a far higher output gain than passive models, too. Add in the ability to EQ the tone beyond a simple tone control, and you have a pretty impressive pickup.
So, why aren’t all pickups active? Well, passive pickups, despite their drawbacks, have a greater dynamic range. If you’re the kind of player that likes to be able to move from whisper quiet, to a screaming wail, then a passive set-up is likely to suit your playing style best. Plus, these types tend to lose high frequency detail, and enhance lower frequencies, giving them a warmer tone.
Conversely, active pickups have backs of sonic detail, but a lower dynamic range. Tonally, they’re sometimes described as ‘sterile’ or ‘cold’. This is, perhaps, a bit unfair, as active pickups can certainly be used to create sounds that pretty explosive.
Their increased output before feedback has seen them become incredibly popular among guitars in heavier, rock genres. Plus, their detailed sound lends itself to articulate passages, such as shred guitar lines, or even jazz.
Which should you go for? It’s all down to taste and playing style. Try a few, and hear the differences for yourself… 😉