But man, it was brought to my attention that I totally forgot about the
lowly old P-90s! Well, let’s rectify
Once again, I need to make it clear that these are my personal
recommendations. You may be going for
something totally different, and as such may want to totally disregard my
suggestions; if so, I fully understand, and rest assured, my feelings will not
be hurt in the least bit.
Okay, now this is important, as far as pickup height is concerned, P-90’s
are an entirely different animal from either humbuckers or single-coils. With a Strat or Tele style single-coil pickup
the magnetic field, or the part of the string being sensed by the pickup, is
soooo small and, even microscopic changes in pickup height make a perceivable
sonic difference. Humbuckers are sensing a much larger portion of the strings
movement, and as such are a little more lenient on pickup to string height
adjustment. From nearly as close as the
pickup can get without touching the strings to as far away as it can be
adjusted, decent tones can be had.
Now a P-90 is an “interesting bird”; tone-wise it’s in the same camp as the
early PAF Humbuckers, in fact, the design goal of the first humbuckers was to
sound just like a P-90, but without the hum!
But, of course from a physical standpoint, the P-90 is much more akin to
a Fender-style single-coil pickup.
However, there are some very important things to keep in mind when setting
the height of a P90:
The P-90 IS a single-coil pickup, but that coil is way wider and more
shallow than on a Strat or Tele style single-coil; the P-90 is also wound with a lot more turns
of wire ie: it’s a lot fatter and hotter. As a
matter of fact a 1957 P-90 has about the same output as a 1957 PAF. Result:
Tonally, the P-90 is more like a PAF humbucker than a Strat single-coil. The narrow coil and (relatively) low output is
a big part of the Fender spank ... and the P-90 has neither!
Fender’s designs employed pole-pieces that are the actual MAGNETS, whereas
the P-90’s use steel screws/slugs (same as the humbuckers), with magnets on the
back-plate wedged up aginst those steel pole-pieces making them somewhat magnetically
charged. This means the Fender pole
pieces have a gauss (magnetic pull) of about 3-4 times what a P-90 has. So again, the result: Tonally, the P-90 is more like a PAF
humbucker than a Strat single-coil. The
strong magnetic pull is a big part of the Fender chime!
And so, setting the height on a P-90 is a lot more like setting a humbucker
than it is a Strat/Tele pickup. Because
the magnetic pull is fairly low (in the 300-Gauss range compared to 1100 for a
typical Strat pickup), you can get by with placing the pole-screws very close
to the strings without worry about it sacrificing string resonance. Because the coil is so wide and the gauss so
low, the P-90 is also quite forgiving placement-wise, although not as much so
as a humbucker which has even less pole gauss and more coil(s) width.
One last thing to mention: P-90’s are
an archaic design from the 1940’s; really, they are the oldest pickup designs
still in regular use. As such, they were
never really designed to be very adjustable.
In fact the earliest versions (often called the “A-90”) didn’t even have
adjustable pole-screws, just fixed steel slugs.
Now, the soap-bar versions generally have a decent amount of height
adjustment available … but those old “dog-ear” versions, well … if ya want to
make any drastic height adjustments to them, you gotta actually “shim”
them. Yep … archaic!
I prefer to use a digital caliper to take measurements, but a quality
luthier’s ruler will do fine if you have excellent vision! Okay, so with no further ado, here are my
suggestions and reasons why.
Low E: 2.6mm / 0.10"
Hi E : 2.35mm / 0.092"
Low E: 4.5mm / 0.18"
Hi E : 3.43mm / 0.135"
(Measurements from the bottom of the
string to the top of the magnetic pole piece screws)
Yep … that’s CLOSE … even a little closer than a humbucker
on the bridge! But here’s why: That old design used a pair of magnets forced
head-to head with a poor old pole screw/slug smashed in between to “charge” the
pole-piece. The measured magnetism (gauss) at the actual pole screws in these is
only about 200-300gauss, compare that to the 1000+ gauss of a typical Strat or
Tele style pickup … there’s a HUGE difference here, buddy! As you raise the pickup closer to the strings
the tone gets brighter and more focused … now with a super bright single coil,
that’s usually a bad thing, especially on the bridge pickup. However, with the relatively warm tone, wide detection
area, and inherently low magnetic pull of these archaic designs, that’s EXACTLY
what makes them come alive
A P-90 sittin’ far away from the strings produces a
downright fluffy/thuddy tone (with a lot of 60-cycle buzz, too) … hey, if that’s
what you’re going for then do it!
Personally, if I want that tone, I just roll down the tone pot and maybe
the volume a little. The
truth is that you might find the tone you are looking for anywhere from the
closest you can get those puppies to the strings all the way to as far as you
can get them away from the strings (about 6-7mm is as far as you can go on a
Les Paul style guitar). As always, just
The closer you get to the strings the brighter,
louder, and more focused the tone will get.
The further you move the pickup away from the strings
the warmer, quieter, and less focused the tone will get.
And here is my last comment on this subject; I have a 1958 Gibson ES125TD with a pair of
original “dog-ear” P90s that are sitting WAAAAY further away from the strings
than the recommendations I just gave above, and I wouldn’t even consider
shimming them up closer. Why? Because
that warm, sloppy, sweet, fat tone is exactly what I’m looking for out of that
guitar … so there, I just discounted everything I’ve said. Go figure!