Active Pickups: All you want to know

Foreword

Nomen est omen: the name I’ve chosen for my blog is strong determination to write a detailed post about “active” technology in guitar world.

Since the first active pickups has been installed into guitars there’re  endless disputes between the lovers and haters.
I don’t want to judge whether the active or passive pickups are better. I believe it depends on the musical style and the personal preference of the musician.
Both type of pickups have some pros and cons and you can find many outstanding and well-known guitar players on both side.

Couple of years ago I owned a Cort KX1Q (a pretty decent model of higher end Corts) that was modded by installing EMG 89 pickups instead of the factory ones. I loved them. They have never felt “neutral” or “boring”‘ for me, my impression was they rather have clean, well defined, balanced tone that could drive a high gain distortion to really helluva hot sound.

Terms

Let’s define first a widely acceptable technical term of active pickup:

Active pickup is a magnetic pickup producing amplified output with on-board electronics using external energy source.

That’s the “conventional” meaning of active pickup.
Well, of course, we can say that all undersaddle piezo pickups are somehow active, because they usually work with a preamp built into the guitar, as well the few optical pickups. However, those systems are separated: the pickup and the preamp are apart, they are located at different places, while the active pickup’s preamp is actually under its cover, practically on the base plate.

There’s also a common misbelief that any guitars with active EQ controls have active pickups (in contrast to passive controls that are able to only cut the tone, active EQ can also increase the gain of the selected frequency range). But it’s far from the truth.
This misbelief is based on the fact that most active pickups obviously HAVE active EQ.

Many budget basses and some guitar models in these days feature cheap and mediocre quality active EQ circuit in the control cavity connected to standard passive pickups. That makes the illusion of playing on an active pickup equipped instrument – but actually, that’s just an active bass or active guitar, with passive pickups.

Long story short: I’m going to write about the built-in preamp equipped magnetic pickup.

Pros-Cons

Why guitars needed active pickups?

The traditional passive PU faced to various expectations from the very beginning – many of them were impossible to implement successfully in one device, because of the laws of physics. Several features needed a certain design while others could be done only with completely different one. Guitarist badly need high output, broad tonal space, even frequency response, high dynamic range and low noise.
A mission impossible, huh?
Well, there are some really well designed pickups as a result of a good compromise between the controversial characteristics – but wait, have you heard the saying “a good compromise is one in which neither side is happy”? 🙂

As the heavy metal got more advanced and popular it generated higher demand for more gain, more distortion – that means higher output. The obvious solution is to increase the number of windings to make “hot” pickups- and it will also increase the inductance and the internal capacity… so we ending up with faded highs and mids, moreover increased tendency to collect noise.

To deal with these problems developers came up with relatively low impedance-low output pickup with integrated active preamp. The result is a low noise – high output signal. Benefits of such design are not only the compensation of the weak signal and protection against electromagnetic noise but it also creates a more balanced frequency response (reduced difference in bass-mid-treble range). Unfortunately, there is a slight unwanted side-effect: peak frequencies in mid and treble range are a bit lower compared with passive.

Additional advantage is that such construction acts like a buffered system: more tolerant to the load of wires, guitar electronics and the amp input – longer guitar cables don’t have a significant effect on its characteristics.

The icing on the cake is that it’s easy to add a multi-band EQ with extended tone control. While the passive tone controls work only by cutting the highs, active EQs can also boost the selected range.

And it’s not over yet! All guitar players know the annoying effect that decreasing the volume on the guitar will also fade and soften the tone slightly. Active pickups are free of this problem.

Alright, that sounds amazing, but where is the catch? It should have some drawbacks… there ain’t no such thing as free lunch!

Battery cavity routed

Battery cavity routed

Active pickups rely on external energy. It raises two issues: the guitar needs an easy to reach place to store a battery (or two) and you can have unpleasant surprise if the battery dies suddenly during your best performance ever. 🙂 Well, actually, the latter isn’t a high risk because these systems can work with a fresh battery for months (depending on the use).
To install a battery holder a cavity on the back should be routed. Wiring of the electronics is also more complicated, however, nowadays solderless wiring systems makes the installation relatively painless for anybody.
Slight disadvantage is that if you want to use one active pickup, you’ve better to replace all. It’s not recommended to mix active and passive because of the different impedance and signal level.
And last but not least: active pickup systems are not cheap. You can buy a decent entry-level guitar for a price of an EMG set.

There are two more so called issues: many “orthodox” player say the active pickups sound flat, sterile, soulless. Well, compared with a vintage type pickup that definitely colorizes the tone with pronounced peaks and uneven frequency response, the more neutral and balanced active may sound “boring”. Another complain used to be related to the more transparent behavior: mistakes, imperfections of the player are more obvious because the active pickup can capture and output more details.

Who needs it?

Active PUs are widely used in basses: many upper-class basses feature active pickups. Bigger headroom, clean, balanced tone, noise elimination and more flexible tone control by EQ are pure benefits for them.

The other main target group is metal players. They love the high output for brutal distortion and the extra mid-boost to pierce through the thick texture of the metal band.

Some jazz guitarists prefer the active pickups because of their balanced, detailed tonal character and high dynamic range.

History

Early Alembic pickup set

Early Alembic pickup set

First commercially available active pickups are made by Alembic from 1969.

Alembic was born in the rehearsal room of Grateful Dead as an experimental workshop to improve the whole signal chain for studio work and gigs. They supported Jefferson Airplane and Crosby Stills Nash & Young, too. Rick Wickershaw, who worked for Ampeg before wanted to improve the relatively weak guitar signal. He designed a low impedance pickup to keep the good frequency response and a preamp circuit to rid of its drawbacks. That process later called “Alembicizing”. The first instrument with such system was Phil Lesh’s modified Guild Starfire bass.

Phil Lesh's Guild Starfire bass "Alembicized"

Phil Lesh’s Guild Starfire bass “Alembicized”

Ovation was also a highly innovative guitar builder. They implemented similar principle in their rather wicked Breadwinner guitar (axes I kinda love!), however, that’s not really an active pickup in the strict sense because the preamp wasn’t integrated into it.

Ovation Breadwinner, the first mass production guitar with active electronics

Ovation Breadwinner, the first mass production guitar with active electronics

Bill & Pat Bartolini begun to experiment in the seventies and they developed the first pickup equipped with active preamp and EVQ tone control in 1977.

Bartolini pickup

Bartolini pickup

No question that talking about active pickups, EMG is the most well known name for all guitar players.

Typical EMG active pickup

Typical EMG active pickup

EMG founded by Rob Turner who begun to build pickups in their garage in 1974. He tinkered with electronics from ’69 mainly repairing radios and amps. In high school times he modified a Stratocaster with an active circuit, but he found the too many cables messy and difficult to shield, so he decided to find a solution to make it noise-free.
Later he continued as a drummer in band but after all of their musical gears has stolen he decided to end up his musical carrier and return to design and build electronics for instruments. Soon he found that repairing amps is not his cup of tea, so it was time to restart the noiseless pickup project.

His early pickups entered the market in the seventies and they were practically almost the same like what we know nowadays as EMG.
After several name changes the well know three letters remained from the eighties: Electro-Magnetic Generator.

Despite the initial success amongst a few pro player the rather traditionalist guitar community was resistant. They couldn’t accept the idea to install a battery in a guitar – “Battery is for the flashlight” they said.
But EMG was at the right place at the right time.

Ned Steinberger with his prototype

Ned Steinberger with his prototype

Ned Steinberger is also one of the most innovative designers in guitar technology. He already made a great contribution in design of the popular Spector NS bass series before he designed the minimalist Steinberger L and GL series. Those “broom” or “paddle” shaped instruments are maybe the most radical guitar innovations since the invention of electric guitar. The stripped down headless construction made of Steinberger’s proprietary carbon-graphite composite, the 18:1 fine tuners integrated into the bridge-tailpiece are divided the guitar community but definitely generated great attention.

Steinberger L2

Steinberger L2

EMG and Steinberger, both pioneers, both has broken with traditions, their cooperation was a natural development. The success of Steinberger also drove EMG towards success.

Steve Lukather, Peter Frampton, David Gilmour, Eddie Van Halen – all early users of EMG. Metal music would not be the same without EMG – said Kirk Hammett of Metallica while James Hetfield called them „Extra Metal Growl”.

Nowadays EMG found in plenty of high end guitars, Jackson, ESP, Schechter, Peavey, B.C. Rich, Wahsburn, Dean.

Factory tour with EMG


Of course, you can find great active pickups in the collection of another manufacturers, too. One of the nist well known is Seymour Duncan’s Blackout series.

Seymour Duncan Blackout set

Seymour Duncan Blackout set

 

Going deep

Okay, okay, but what is all about in details? I’m sure some of you are eager to know more about what is under the hood.
I’ve found a great “reverse engineering” to reveal the secrets of the technology. Kudos to the daring Fred Briggs!

Inside of and EMG

Inside of and EMG

Stacked EMG SA

Stacked EMG SA

The most details can be seen on the famous EMG-81, perhaps the most popular

EMG-81, wax potted, with ceramic magnet

EMG-81, wax potted, with ceramic magnet

EMG-81 bottom inside

EMG-81 bottom inside

The following are unofficial details about the design of EMG 81.

  • 56 x 3 x 13 mm size ceramic magnet
  • 0,06 mm-es wire
  • 5700 winding, 4,18 KΩ resistance
  • potted in wax
  • unknown type „EMG001” op-amp, most probably LM4250
  • One coil is connected to the inverting, the other is to the non-inverting input.
The mysterious EMG op-amp, most probably LM4250

The mysterious EMG op-amp, most probably LM4250

EMG-81 coils and steel bobbin

EMG-81 coils and steel bobbin

By the official specs it features strong ceramic magnets and thight winding, that ensures the intensity of details and the outstanding high and sustain.

A guitar nut (nicknamed “Bajaman”) even reverse engineered the circuit and reproduced it by building his own version.

Bajaman homemade EMG replica

Bajaman homemade EMG replica

If you want to do so, find the details here!

Credits to the Sources:

SoundOnSound

Ovnilab

Premier Guitar

ProGuitarShop

 

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