Vintage Fender Guitar Pickup Spec
Info 10/10/05. Return to the Feature
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Introduction.
Ok, I admit i'm not an electrical engineer. But I get asked about
vintage Fender guitar pickups quite often, so here's some info in case
you're curious. Most of this information is from Seymour Duncan.
Terminology
- Single Coil Pickup: All vintage Fender pickups are
single coil units. This compares to Gibson, which started using double
coil (Humbucking) pickups in 1957. Single coil pickups have a single
slab of wound wire around magnet(s). Single coil pickups are easily
influenced by outside noise. This would include 60 cycle hum and
fluorescent lights.
- Humbucking pickup: This type of pickup has two single
coils combined into one unit. Each coil is reverse wound so that the
hum from first coil cancels the hum from the second. The two coils are
wired in series so the total resistance is additive, hence producing a
"hotter" and quieter pickup (if the two coils were wired in parallel,
the total resistance is half the sum of the resistances of each
individual coil, assuming both coils are about the same resistance). In
either case (parallel or series), the hum does cancel, hence the name
"Humbucking". Note the difference bewteen parallel and series wiring of
pickups/coils. Parallel is why the "in-between" setting used on a
Stratocaster (combining the middle pickup with the neck or bridge
pickup), does not produce a Humbucking pickup sound. Also, the
in-between switch setting on a Humbucking two pickup Gibson is less
powerful than each pickup individually. The two Humbucking pickups are
combined in parallel (even though the two coils of each pickup are in
series), thus giving the average of the two pickups divided by two.
Interesting, huh?
- Ohms: messure of resistance. The longer the pickup wire and
more turns used, the higher the resistance. Also the higher the
resistance, the louder or "hotter" the pickup. But be aware, higher
resistance comes at a cost: lose of treble frequencies. This is why
single coil pickups have more treble and less output than Humbucking
pickups (which use two coils). Hence Humbucking pickups have more
mid-range and are "hotter". Also this is why single coil pickups that
are wound with tons of wire (to approach Humbucking ohms) don't sound
very good.
- Turns or Windings: this is the number of turns of wire used
on the pickup. Fender had a mechanical counter attached to their
winding machines that counted the turns. These vintage pickup winding
machines were manually run by humans, so the exact number of turns can
vary from pickup to pickup.
- Winding Direction (WD): This is the direction in which the
pickup was wound. Seymour Duncan's terminology best describes this: TL
means the top of the pickup bobbin is facing left. TR means the top of
the pickup bobbin is facing right. TG means the top of the bobbin is
turning away from the winder. TC means the top of the bobbin is turn
towards the winder. Reversing the winding on a pickup will reverse the
phase of the pickup.
- Magnetic Polarity (MP): This is the magnetic polarity on the
top side of the pickup. All magnets have two poles: north and south.
Reversing the poles of a pickup will also reverse the phase of the
pickup. Note vintage Fender pickup magnets are the Alnico type,
consisting of Aluminum, Nickel and Cobalt. They are "sand cast", and
hence have a crude, rough look with pitting left from the sand cast.
The tops of the magnets are ground flat. Usually the magnets have one
end chamfered, which helps guide the magnet thru the vulcanized fibre
flatwork (this is very noticible on Strats, and non-existant on pre-1955
Teles). Pre-1965 magnets are inconsistent in diameter, ranging from .185
to .197". But for the most part, they fit very tightly in the flatwork.
Starting in 1965, the diameter seemed to get narrower by a few thousands
of an inch. Hence the flatwork did not fit as tightly around the
magnets. This causes many 1965 and later Fender pickups to "warp", where
the flatwork will actually buckle and curve. Mid-1960's magnets have a
smoother edge, and eventually the chamfering of the pickups stopped
entirely by the early 1970's.
- Flat Work: this is the vulcanized fibre portion of Fender
pickups. This material holds the magnets in place (and the windings of
the pickups then go around the magnets). Pre-March 1964 Fender pickups
used black vulcanized fibre flatwork. After approximately March 1964,
this changed to a light gray vulcanized fibre. Then again in the early
1970's, it switched back to black vulcanized fibre.
- Hand Winding: This is also known as "scatter winding", where
the pickup wire is wound on the bobbin in a random manor. This is how
Fender pickups were wound prior to 1965, since it was a semi-manual
operation, using a machine to turn the pickup bobbin, while a worker
would guide the wire onto the turning bobbin. In 1965, Fender changed
to "machine winding", as it is a completely automated process. Machine
winding takes away much of the character of the pickup. A lot of the
sound of old Fender pickups is due to the random layering and variable
winding tension of the wire, which effects the tone. With machine
winding, this is all very sterile and consistent. If you see the chart
below, notice how consistent the Strat pickup specs get when machine
wound (after 1964). Not much variance from year to year with machine
winding.
- Insulation: this is the surface coating that is baked on to
the wire that prevents the turns of the pickup from shorting out. We are
all familiar with the insulation on larger wire: usually it's a PVC
plastic coating that you have to strip away when connecting. But on the
extremely thin wire used in pickups, this insulation is a bake-on
coating. There are several different type of baked-on insulation:
Formvar, Plain Enamel, or Poly. Fender used Formvar till about March
1964, when they switched to Plain Enamel. This happened at about the
same time they switched from black flatwork to light gray flatwork.
- Wire Outside Diameter (OD): this is the outside diameter of
the winding wire, not including the insulation. The thinner the wire,
the higher the resistance (ohms). Though this has less of an effect on
resistance compared to the number of windings.
- Wire Gauge: this is the gauge of wire as advertised by the
wire manufacturer. Fender basically used 42 gauge wire for everything
but the Telecaster neck pickup (43 gauge). Note the actually outside
diameter (OD) varies slightly even though it's the same gauge. As the
gauge number increases, the OD of the wire decreases (42 gauge wire is
thicker than 43 gauge wire).
- Potting: dipping a pickup in wax to seal the windings to
minimize vibration so the pickup feedbacks less (and is not
"microphonic").
Why do Vintage Fender Pickups Sound so Good? There are
probably a lot of little factors that make the older Fender pickups sound
so good. Not a single one of these factors will change the tone
significantly. But when all added together, the sum of the parts is better
on older vintage Fender pickups. These factors would include:
- Magnets: pre-1965 Fender pickups used larger diameter magnets
and were sand casted. Also vintage Fender magnets are Alnico and not
Ceramic. Finally, as time goes on older magnets lose some of their
power. The less power the magnets have, the better the strings can
vibrate. Powerful magnets can actually pull the strings towards the
pickup, dampering the vibrations. So there needs to be a balance,
because you don't want too strong or too weak magnets. So maybe after 30
years, the magnets are at their "ideal" power, thus producing "ideal"
tone. Another thing that is different is the "stagger" pattern. That is,
the height of the individual magnet pole pieces. For example, today no
one uses a wound third (G) string. But prior to Hendrix, most players
did. To compensate for this, the fixed magnet heights were different on
older Fender pickups.
- Windings: handwound pickups (like pre-1965 Fenders) seem to
sound better. It's hard to say why, but the scatter-winding pattern and
tension at which the wire was wound was apparently ideal on pre-1965
Fender pickups. The handwinding tonal difference may be due to a lack of
distributed capacitance when scatter-wound.
- Wire Insulation: the insulation on the windings of vintage
Fender pickups have different chemical composition than newer wire.
Even though the gauge of the actual wire is the same, the thickness and
composition of the insulation is different. This changes the total size
of the wound windings. This in turn changes the inductance and
capacitance of the pickup, and hence the tone. Fender used Formvar
insulation till about March 1964. Then they switched to Plain Enamel
insulation.
- Pots: the older potentiometers used have wider tolerences
than newer pots. This may sound dumb, but it could change the tone
slightly.
- the Guitar itself: older instruments have older and harder
finishes. And they also used nitrocellulose finishes that were applied
very thin. Also the wood itself is older and different than wood today
(less polution back then means "cleaner" wood). This will also effect
tone.
- Time: even if all the above are paid attention to and
duplicated, time is something that just can't be made up for. Maybe they
sound better because they are just older...
Why do Vintage Fender Pickups Die?
After many years of use, Fender pickups die much more regularly than
any other brand of pickups. Even Gibson pickups from the 1930's don't
die like Fender pickups from the 1950's. Actually, the reason has to do
with the design and materials of Fender pickups themselves.
Since the windings of older Fender pickups are in direct contact with
the magnets, this has caused some problems. With time, the magnets seem
to chemically react with the windings/insulation, causing the windings
to break. Once a single inner-most layer of winding is broken, that's
it; the pickup is "dead". Due to magnetic fields, the pickups may still
work, but it will sound extremely thin and weak. Also, if you
turn down the Tone control to that pickup, it will go complete dead and
silient. That is a sure test of a dead Fender pickup. You can also
measure the Ohms of the pickup. Dead pickups will register "open" (no
resistance). But because the pots are in-circuit, an open pickup may
read some bizarre high resistance, and the value may bounce up and down
(again, due to the magnet properties of coils and the pots in the
circuit). You should do the Ohm test right at the pickup leads, and to
do it right, have one lead disconnected from the circuit (but please
don't desolder any vintage guitar pickup leads!) Also the position of
the pickup switch can effect values too, as can your fingers if they are
touching the meter's probes. Just keep that in mind.
Another thing that kills old Fender pickups is someone trying to
"adjust" the (non-adjustable) pole pieces (magnets). Because of the lack
of a wound third (G) sting, some musicians push the G string magnet
down through the flatwork, moving it further away from the strings. The
problem is this can tear the inner windings. Since the magnets are in
direct contact with the windings, and the magnets are sand casted and
have rough sides, this will easily tear a winding. One torn winding will
create a dead pickup (see the paragraph above).
Newer Fender pickups have been able to avoid both of these problems.
Now, after the magnets are installed in the flatwork, lacquer is sprayed
over the magnets and flatwork. Then the wire is wound around the
magnets. This means the magnets are no longer in direct contact with the
inner windings. Therefore, if the magnets are pushed thru the flatwork,
they are less likely to tear the windings. Also there is less chance of
a chemical reaction between the magnets and windings as they are
insulated from each other by the lacquer.
Vintage Fender Pickup Specs.
These specs are thanks to Seymour Duncan. He does excellent vintage
reissue Fender pickups and Fender rewinds. Unfortunately, he's too busy
to do rewinds much any more - too bad for us all. He used to fix
dead Fender pickups by unwinding the original wire, fixing the internal
break, and re-winding the original wire back on the pickup! But this is
very time consuming, so don't even bother asking him to do it now, as
he's very busy (he'd keep busy for a long time just fixing all my dead
Fender pickups alone!).
The following table shows Stratocaster pickup specs from 1954 to
1967. Seymour got this data from the thousands of Strat pickups he has
fixed or rewound. He then averaged the data together by year, and came
up with this table. Note the magnet polarity was changed in 1960 (even
though Seymour thought it was 1958, other data suggests it's more like
1959/1960).
1954 to 1967 Fender Stratocaster Pickup Specs
Year |
Ohms |
Wire OD |
Insulation |
Turns |
WD |
MP |
Wound |
1954 |
5.76k |
.0030" |
Formvar |
7956 |
TL/TG |
North |
Hand |
1955 |
5.89k |
.0029" |
Formvar |
7844 |
TL/TG |
North |
Hand |
1956 |
5.98k |
.0029" |
Formvar |
8012 |
TL/TG |
North |
Hand |
1957 |
6.02k |
.0029" |
Formvar |
8105 |
TL/TG |
North |
Hand |
1958 |
6.20k |
.0028" |
Formvar |
8350 |
TL/TG |
North |
Hand |
1959 |
5.95k |
.0030" |
Formvar |
7925 |
TL/TG |
North |
Hand |
1960 |
6.33k |
.0028" |
Formvar |
8293 |
TL/TG |
South |
Hand |
1961 |
6.19k |
.0029" |
Formvar |
8119 |
TL/TG |
South |
Hand |
1962 |
6.22k |
.0028" |
Formvar |
8220 |
TL/TG |
South |
Hand |
1963 |
6.37k |
.0028" |
Formvar |
8319 |
TL/TG |
South |
Hand |
1964 |
6.25k |
.0027" |
Formvar/Enamel |
7980 |
TL/TG |
South |
Hand |
January 4, 1965, CBS bought Fender Musical
Instruments. |
1965 |
5.80k |
.0026" |
Plain Enamel |
7626 |
TL/TG |
South |
Machine |
1966 |
5.76k |
.0026" |
Plain Enamel |
7630 |
TL/TG |
South |
Machine |
1967 |
5.88k |
.0027" |
Plain Enamel |
7656 |
TL/TG |
South |
Machine |
Year |
Ohms |
Wire OD |
Insulation |
Turns |
WD |
MP |
Wound |
The following table shows the difference in pickups by Fender model.
Wire specs (gauge, insulation) are for the earliest models produced.
Again, this is an average of data from Seymour Duncan.
Fender Pickup Specs by Model
Model |
Wire Gauge |
Insulation |
Avg. Turns |
1000 Pedal Steel |
42 |
Formvar |
8000 |
400 Pedal Steel |
42 |
Formvar |
8000 |
5 String Bass |
42 |
Plain Enamel |
12,000 |
Bass VI |
42 |
Formvar |
8550 |
Deluxe 6 LapSteel |
42 |
Formvar |
8350 |
Deluxe 8 LapSteel |
42 |
Formvar |
8550 |
Dual 6 Steel |
42 |
Formvar |
8350 |
DuoSonic |
42 |
Formvar |
8350 |
Electric 12 |
42 |
Plain Enamel |
12,500 |
Electric Mandolin |
42 |
Formvar |
8000 |
Jaguar |
42 |
Formvar |
8550 |
Jazz Bass |
42 |
Formvar |
9000 |
JazzMaster |
42 |
Formvar |
8500 |
Mustang |
42 |
Formvar |
7600 |
Precision Bass |
42 |
Formvar |
10,000 |
Stratocaster |
42 |
Formvar |
8350 |
Telecaster (lead pu) |
42 |
Formvar |
8000 |
Telecaster (neck pu) |
43 |
Formvar |
8000 |
Model |
Wire Gauge |
Insulation |
Avg. Turns |
Potting a Pickup.
If you are having problems with a pickup being "microphonic" or
feedbacking, sometimes you can fix this. WARNING: be careful! you can
ruin a perfectly good pickup trying to pot it. For this reason, I
recommend letting a professional do this for you.
Anything that can vibrate on a pickup can cause feedback: the covers,
loose boobins, a loosely wound coil, a loose baseplate (Tele pickups),
loose magnets, etc. Humbuckers with the covers can excessively feedback
too, so you can pot them with the covers on to minimize feedback. The
idea is to fill the space between the bobbins and the cover and secure
everything in place.
In order for the wax to penetrate the coil, the entire pickup first
has to be as hot as the wax's melting point. That takes time. As the
wax penetrates the coil you will see air bubbles coming out of the
pickup. It is not saturated until the bubbling stops, which can take 2
to 10 minutes. The tape around the coils does not need to be removed,
the wax will get in just fine. It is absolutely crucial to monitor the
wax temperature and keep it below 140 degrees or else the bobbins will
melt and distort, killing the pickup. A special blend of parafin and
beeswax guarantees a low melting point. Wax that is heated too much
without temperature monitoring can spontaneously combust like fuel.
This is very dangerous. DO NOT PUT IT IN THE MICROWAVE. A "double
boiler" is the best way to heat wax. This involves putting the wax in a
container, and then putting that container in a pot of hot water. The
Water is heated directly by the heat source, not the wax container.
If you only have one or two pickups to pot, buying the wax will cost
you more than having the job done professionally.
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