ACTIVE VS PASSIVE PICKUP
Magnetic pickup for electric guitar and bass can also be distinguished in two sub families:
active and passive.
The power and tone of a passive pickup originates from a series of parameters among which power and type of magnet, length of the bobbin, strength of the bobbin, diameter of the bobbin wire, type of wire and insulation, ecc.
Active pickups also include a small bobbin, similar to the one of passive pickup, but its influence is relatively low and most of the tone is generated by a preamplifier built inside the pickup itself. Therefore the sound of the pickup mostly depends on the frequency response of the built in pre which is set by the manufacturer.
On of the advantages of this is that, due to the reduced influence of the magnet, placing active pickup near to the strings doesn't have any negative effect on the vibration and sustain.
Active pickup offer some real advantages over passive ones.
For example active pickup feature a reduced noise due to the low impedance which allows the use of very long cables without loosing any part of the signal
and allowing a better and more silent interface between the instrument and other effect devices like multi-effect devices, pedalboards, sound interfaces, plugins, ecc.
I do not totally agree on that instruments equipped with active pickup feature a "colder" tone and tend to sound all the same.
My opinion is that wood, especially the neck one, still has a lot of importance on electric instruments equipped with active pickup.
Having served thousand of musicians in 35 years, I have learned that the diffidence toward active pickup is usually generated by the presence of the battery which may hurt some players fearing it gets suddenly drained without any advice.
HINTS AND TIPS
Active and passive pickup works on a totally different impedance thus requiring totally different values of volume and tone potentiometers and capacitors. Therefore it's impossible to mix them on an instrument without damaging the performance of one of the two if separated volume and tone for each pickup are not present. Even in this case the volume of the active pickup will be much higher than the passive one.
I have developed some original schematics diagrams for applications with EMG pickup like for example:
- using the EMG Mid Boost on only the two single coils of a H/S/S equipped guitar
- EMG preamp true bypass.
I have sent these to EMG in the past and they admitted that indeed it was "a better way to do this" but for some reason they never published them in their schematics book.
If you're interested please contact me.