I'm asked by players, over and
over, " How much output do your pickups have?" This is a very disturbing
question because one should consider, no matter how much output your pickup
has, you'll never get more than 50 watts out of a 50 watt amplifier!
Rating Pickups with DC Resistance
is NOT a power rating; it is the resistance of the wire in a pickup's
coil at zero hertz, something that only occurs when the guitar isn't played.
If some marketers use DC resistance as a power rating for an AC device,
like a pickup, then they only show their ignorance. If we use
DC resistance as a parameter, we disregard the fact that, due to Pe and
other conditions that result in eddy currents, the effective resistance
(Rac) is frequency dependant.
(Rdc) tells you as much about a pickup's tone and output as the shoe size
tells you about a person's intelligence!
The output rating of pickups is generally given in millivolts (mV).
Millivolts could be a helpful parameter if all manufacturers would agree
on a standard measuring method that provides such data over a wide frequency
range. Now, let's say with this information, we plot an impressive-looking
graph showing the different output levels at various frequencies -- does
this give you a good idea of the sonic character of a pickup? Yes and
no. Don't forget that not every guitar is created equal, and neither
are the players. We use different kinds of strings, cables, amps and
speakers, and a pickup is only one link in
a chain that finally determines tone and output.
Inductance ( henry) is another valuable parameter for the sonic evaluation
of a pickup but requires some basic understanding of electrodynamics.
As a general rule, the higher the inductance, the lesser the highs. For
example, a traditional strat pickup has an inductance around 2.3 henry
while a Gibson PAF has an inductance around 4.4 henry and some of the
so-called "distortion" pickups have an inductance above 8.0 henry. With
these comparisons, you get a basic idea. Besides inductance, there are
other factors that also need to be considered in projecting tone and output
of a pickup.
Tone and output mainly depend on the relation between inductance, magnetic
strength and the efficiency of the pickup, as well as the relation between
the inductance of the pickup and the capacitance of the cable.
© 1996-2010 Bill Lawrence