6 x Alnico pole pieces (Unmagnetised, Alnico 2, 3, 4 or 5, either 5mm, 3/16" or 1/4")
I wanted to
write a guide to this type of pickup for a while, a sort of, “This is what the
parts do, use them in your designs as you see fit, these are the variables”
And that might
seem a little “cruel” in a way, because, I know if you’re just starting out
winding, you want someone to sit and explain the very basics of pickup winding –
but that’s a little beyond the scope of this– so, for the sake of keeping it as
simple as possible, I’ll stick to what we’re looking at here, and I’m going to
assume everyone reading has a basic understanding of “winding” and a little bit
of understanding about the electrical theory behind pickups (otherwise, I’m writing
my a book trying to explain inductance and resonant peak!) – I’ll touch on the
basics, but I won’t get bogged down in the “why”.
Lets get
into it!
What is
a pickup for a Tele® bridge?
So, in short, pickups for the Telecaster® bridge slot are, basically, single
coils – there’s a few weird considerations with them , but on the whole, it’s a
coil of wire wrapped around a frame made from alnico poles pressed into fiber
boards – not really all that different to the single coils you’ll find on a
Stratocaster®
But, just like a Strat® pickup, the details are all in the minutia – so, the
purpose of this write up is to explain what all those little variables actually
“do”
Now, as a VERY rough and ready guide, bridge pickups on the Tele® are differ in
a couple of ways!
Phase
& Polarity
Firstly, they’re “usually”, reverse would, reverse polarity (Counter clockwise
winds, North top) – the same as a Strat® middle pickup. That’s one we see
people get wrong more often than not – the assume the neck is the reversed
pickup in the circuit – its not! Its almost always the bridge. Now, this doesn’t
really matter if you’re winding for yourself, but it’s a good rule to “stick to
the standards” because if you do end up selling your pickups, or you try mixing
and matching them with other manufacturers models, you’ll run into issues with
phase and polarity.
Be aware too, that not all “big” manufacturers follow this rule either! Fender®
themselves make Telecaster® pickups that are “wrong” on occasion – usually it’s
for historic reasons (early models didn’t always follow modern standards), so
keep “the standard” in mind, but take pickups on a case-by-case basis. The
oddities are out there, just waiting to trip you up!
Pole
Setup/Staggering
Flush
poles
Telecaster®
pickups usually turn up with “flush poles” – where the alnico rods pressed into
the fiber boards sit flush to the top face (and bottom face) of the fiber
boards – this is was done to maximise the amount of “coil space” you’re working
with, and, as time goes by, flush topped pickups have become very fashionable because
“that’s how Fender® did it”
And, yes, it does have its advantages – you can normally max out a pickup for a
Tele® with about 10K of 42 AWG, however, it’s not without its problems!
Single coil frames built up with flush mounted poles don’t hold up all that
well to finding. There’s always a certain amount of “board warp” when winding a
pickup – there’s so much copper being piled on there, under tension, that the
poles come under compression, and the copper is literally pushing against the
boards as the coils build up.
The bottom
board accounts for this, by, traditionally, being thicker, to limit the warping(at
2.4mm) but top boards are, inexplicably, 1.6mm – I assume, the idea of a “flush
pole” came after the boards were designed (or thinner boards have crept into
being later because most other pickups DON’T have flush pole) – either way,
that thin top board has very limited “grip” against the poles, and its not
uncommon to see pickups with flush poles where the top board have warped to
such an extent that they have lifted away from the poles.
It sounds a terrible design flaw, but, really, its quite easy to fix. When you’re
assembling the frames, after you’ve pressed the poles into place, a quick blob
of super glue up against the pole where it meets the fiber board will eliminate
any problems.
Its worth, after doing this, wrapping the poles with a layer of paper tape
though, because the CA/super glue can end up being a little rough and increases
the risk of snapping the coil wire.
Staggered
Poles
Staggered
poles are simply “poles that sit above the fiber board at different heights to “match”
the strings”. I can’t say I’ve ever noticed any difference in tone myself, but
it was originally designed to account for wound G strings and volume discrepancies
between strings apparently. It’s been the norm on Strat® single coils since day
one, but never really caught on with the Telecaster®
Whilst much
less common, they do exist (we use them on our Yorkshire Jack, and it’s a fantastic
little pickup!) – they’re simpler to assemble, because they don’t require gluing
(and board warp doesn’t cause the boards to pop off the poles), but, as you can
imagine, they reduce the amount of space available for your coils.
Now, one of the temptations when winding a bridge pickup for a Tele® is to try
and make a “Strat®” pickup – 6K of 42 AWG, shorter internal height, staggered
poles! It’s a lovely idea! However, it doesn’t really work believe it or not.
For whatever reason (and I can’t say I’ve explored the idea beyond the initial “suck
it and see” test!) – what works in a Stratocaster® doesn’t work when mounted
into the Telecasters bridge plate – its lacking in power and sustain. I imagine
its something to do with the actual bridge being made from metal, and the
magnet field being dissipated.
So, go in
eyes open – staggered poles aren’t a short cut to the ultimate hybrid pickup, and,
I doubt pole staggering in itself actually changes the tone of a pickup all
that much, BUT, it’s a neat way of making the internal of the frame smaller,
and as such, changing the tone of the pickup.
As a very rough and ready rule, the smaller the pickups internal space, the
higher the inductance (the “hotter” the pickup becomes, the lower the frequency
of the resonant peak/wider the Q factor) – basically, short coils make more
aggressive pickups, and because your limited on space, you’re likely winding
using 43 AWG or 46 SWG, and that plays right into your wheel house, because
those wire gauges are generally used to make more aggressive pickups! As a nice
ball park to play with, aim for a 10K coil fo 43 AWG with a staggered pole setup
– it’s a fantastic “modern” Tele® tone!
Board Colour
This is a nice
easy one thankfully – its purely a “historic” thing (or a cosmetic thing, depending
on how you think about it!). Purely the colour of the fiber boards you’ll be
pressing your poles into.
Originally, it’s very likely that the
Telecaster® (then, the Broadcaster and the Esquire®!) was initially intended to
be wound with 42 AWG “heavy build” Formvar (as was the early Stratocaster®) –
however, because Formvar only exists in “heavy build” (essentially, 2 layers of
insulation on the copper opposed to “single build”, which would have 1) is takes
up a lot of space on the frame, so, for whatever reason, I imagine that caused
problems and Fender® switched from 42 Formvar on the early models to 43 AWG
Plain enamel “Single build” (I can’t say I know why they didn’t switch to 42
AWG Plain enamel, because that would have been the logical step (and the one
they eventually took further down the line!) but early Tele® pickups? 10K of 43
AWG, flush poles! Very distinctive tone! Doesn’t sound how you think a guitar
from 1950 should!)
Either way, whatever the reasons, we see these pickups turning up with dark
brown or purple insulation on the copper, and, frankly, its an absolute pig to
work with on black boards. You can’t really see the start and finish of the
coil wire all that clearly (but you CAN, if it’s the bright orange Formvar!) – so,
as a quick guide – very early pickups committed “The Cardinal Sin” because they
were originally meant to have been wound with very vivid orange wire!
so, from 1950 until about 1963 the Telecaster used Black boards top and bottom
on both bridge (at some point in the 50s, the bridges DID switch to 42 AWG
Plain enamel) and neck pickups. After that, we see a switch to grey bottoms and
black tops (this is true for the Strat® too, because at that point, they
switched over to Plain enamel too). Simply because you can actually see the
coil wire, and your less prone to snagging it during termination.
There has never, officially, existed a Grey/Grey or Grey Top/Black base – but,
we’re talking winding your own pickups here. Do whatever you want! The weirder
the better in my book!
Magnets
Now, this
is about as big a topic as you’re going to get when it comes to pickups! Be they
Single Coils, Pickups for the Tele®, Bar Magnets in Humbuckers and P90s? A huge
amount of nonsense is written about “what magnets actually do” and, in
fairness, I’m prone to writing most of it off as gibberish, a lot of what’s
written actually is based in fact! The problem is, its based in “facts” based
on “all guitars” – when you get into specifics (let’s say, just “Tele®
bridges!) – what magnets are doing is pretty easy to pin down.
Grade
When we
speak about rod magnets, like with this kit, we’re talking about Alnico (other
magnets do exist as rods, they’re either very rare, or are too strong to be
used in a guitar! Samarium and Neodymium being the main “Please, don’t do that!”
alternatives) and Alnico comes in different “grades” – technically, that relates
to the “composition” of the alnico (which is an alloy of Aluminum, Nickel,
Cobalt, Iron and Titanium) – basically, different percentages of each element
within the alloy change the grade, and, as you can imagine, there are hundreds
of different grades as a result.
This, however, is utterly meaningless to us as guitarists/pickup builders, so
we break down the “grades” based on the “magnetic strength” – how “strong” the
magnet is when fully charged. This is a measurement called “Gauss” – the higher
the gauss, the strong the magnet.
With that
in mind, we break down the grades, weakest to strongest, Alnico 3, Alnico 2,
Alnico 4, Alnico 5, Alnico 6, Alnico 8.
This is slightly murky however, because magnets get “stronger” the bigger they
are – so its difficult for me to sit here and say “alnico 2, that’s 7500 gauss!”
– but, in reality, a 5mm pole isn’t going to be reading that on a gauss meter. I
can’t say I know how the “stated gauss” measurement is actually taken –but I imagine
it’s a certain mass/area of magnet to keep the readings uniform.
So, this brings up a strange situation that the following rules are only true
when the magnets remain the same size/mass – as soon as you bring in a larger
or smaller magnet, the gauss increases/decreases, and changes the
characteristic of the “tone” being produced (so, potentially, a ¼” Alnico 5
will be “stronger” then a 3/16” Alnico 8!)
Either way –
assuming we’re keeping all things equal – change magnet grade within a pickup,
the higher the gauss/the stronger the magnet, the stronger the pickups resonant
peak (with single coils!) the peak frequency doesn’t actually change, but the
voltage produced at that peak does (essentially the pickup becomes more defined,
crisper, or snappier), increases with strength. However, it isn’t a drastic
alteration! It’s a fairly subtle change. You’ll struggle to hear it on a
recording, but you WILL feel it as a player.
The only exception that I’ve seen, are alnico 4 (which is, in itself, a weird
magnet, because it doesn’t, technically, exist (it would be considered a “flawed”
alnico 5). For whatever reason, Alnico 4 DOES alter the frequency when compared
to Alnico 5, but DOESN’T reduce the voltage.
So, as a rough and ready guide? The weaker the magnet, the smoother and more
rounded the pickup will sound, the stronger the magnet, the more “snap”,
definition and “bite”. That’s true for the “common” pole choices of 3, 2 and 5!
4 will make a pickup similar to Alnico 5, with that definition, but it will be
slightly darker, slightly “throatier”. Not a common choice for single coils
truth be told, but not without its charms!
(I’ve tried
to avoid using emotive language here, which is difficult to do when we’re
talking about pickups – but electrically and perceptively, that’s what’s
happening! Taste plays a big part in this though. Your idea of snap and bite
might be VERY different to mine, and how we perceive the resonant peak is dependent
on where in the frequency spectrum it is! A 20K single coil with Alnico 5
magnets isn’t going to be snappy or bright… that’s what the signals doing, but
the resonant peak is so low, and the Q factor so wide, that its not what you’ll
hear… all we can say, is that it will be “more defined” with a stronger magnet
then it would have been with a weaker magnet!)
Diameter
This sort
of plays into what I’ve mentioned above, but I’ll go into a little more of the
practical aspect here. Its an absolute quagmire though, so be warned!
As I’ve said, the “bigger” the magnet, the stronger it is, so a ¼” pole is “stronger”
than the same grades equivalent 5mm, and the 3/16” is weaker.
Historically, this type of pickup is actually wound with 3/16” poles too, but,
honestly? I like a 5mm pole, so that’s what we use for most of our builds,
because its available in the widest range of grades, however, for historic
jobs, the 3/16” poles are part and parcel of “the tone” too (thankfully, very
early Telecaster® aside, they’re always alnico 5!)
Now, here’s where we end up in a really confusion situation I’m afraid.
Whilst its very simple for me to say “bigger magnets are stronger” and imply
that “if you want a snappy, bright, biting pickup, go for a ¼” pole!” – that actually
not true!
Because of the way single coils are built, the “frames internal diameter” is
set by the pole diameter – so a pickup with ¼” poles will have an internal
width of 6.35mm and a length of (in this case) 60.35 – so lets assume each “wrap”
of wire is 133.4mm. (that’s only true for the first layer, but you get the
idea)
If we take a 5mm poled frame, the same measurement, would be 128mm.
Now, we’re bordering on the hypothetical here, but just to keep the numbers
simple.
Lets pretend that this type of pickup has 10000 winds, each one the same
length, and every 1mm of wire has a resistance of 0.001K
The 1/4” version has taken 13.34Km of wire, and the 5mm version has taken
12.8Km!
And the resistances end up being wildly different as a result! 13.34Kohm vs
12.8kohm.
So, whilst the rule regarding “Bigger magnets are strong, and as such, make the
pickup more defined” is very true – its actually impossible to make 2 identical
coils with different pole diameters! There will always be “more” copper on the ¼”
version compared to the 5mm version (and the same for the 3/16” – 11.75kOhm) and
as such, a different tone! As a VERY broad guide line, the more copper, the
darker the pickup (specifically, the higher the inductance, the lower the resonant
peak, and the wider the Q factor)
AND we’ve got to account for the inductance of the pickup too (if only if they
were just a measurement of resistance, eh?) – inductance is the “strength” of
the pickup, and is generated as a combination of the amount of copper in the
coil and the amount of IRON within it.
So, with a ¼” pole, we known we’ve got considerably more iron within the coil
too! (Because it’s part of the Alnico alloy) So not only is the length of the
copper different, the mass of the copper is different as a result, but also the
iron content is different!
So, really, its actually not really viable to make direct comparisons between
one pole diameter and another, because by its nature, it changes too many of
the other variables, and as such, the tone of the pickup.
Now, there is an elephant in the room after all that. Another reason why making
direct comparisons between one wind and another, with different pole diameters
is, really, pure fantasy!
Your “average” pickup for the Telecaster has 13mm of “width” for the coil
(assuming 5mm poles) – that’s 6.5mm “all around” the poles to try and shoe horn
as much copper as you can into. And that “external size” is set in stone – it got
to fit into a Telecaster® bridge plate.
A 1/4” pole, being larger, will eat into that space (leaving you 5.8mm all
around) – you’ve actually lost 0.7mm. Might not sound a lot, but we’re dealing
with wire that’s 0.06mm or less – and each layer can contain over 200 winds – that’s
2200 “lost” (by the “fake math” from earlier, that’s as much as 2.2Kohm! (it’s
actually much higher in real life, but let’s make believe the coil at the end
of a pickup is the same length as the one at the start).
And, as a result, you really don’t have a lot of room to work with on a Tele®
bridge pickup with ¼” poles, so, more often then not, we see them wound with 43
and 44 AWG rather than 42 AWG, and, honestly, that suits them pretty well –
that extra definition and snap from the big, strong poles matched up with a
higher wind/lower inductance/more compressed tone that comes from thinner wire?
Its quite a nice tone for rock and metal work!
So, there you have it I suppose. Pole Diameter is doing an awful lot when it
comes to how the pickups behaving, much more than the magnet grade ever can,
but, because we’re ultimately limited by the outside shape of the pickup, we can’t
always use the idea to its fullest potential, because bigger poles take up more
space, and limit us on wire gauge.
Going the other way, smaller poles (3/16” vs 5mm) are a little more open to
exploration and comparison, but because the difference is so small, its not
exactly a rich vein to be exploring (less then 2 “layers” of space gained opposed
to 5mm – 0.4kohm in fake math)
So, in closing on pole diameter? Bigger magnets make pickups brighter, but they
also, potentially, increase the amount of copper, and definitely increase the
inductance, so make the pickups darker, and, ultimately, its all a little
academic, because you can’t really wind them with the same wire, you’d use on a
5mm pole anyway, it will be thinner (so the inductance drops)
I could, potentially, go round in circles for the rest of time with this! Easy recipe?
Use ¼” poles and 43 AWG to make very hot sounding single coils. Heavy metal,
rock, anything with a real focus on low end aggression. Anything else? Stick
with 5mm, unless you’re chasing an ultra historically accurate setups, then 3/16”. Forget we
ever spoke about comparing pole diameters and get back to laying down some
copper wire!
Base
Plate
After the pole
diameter write up, I feel I’m on safer ground here! Pickups on the Telecaster®
bridge come with a metal base plate (usually!) – no ones really sure as to why
they do, but its commonly believed to have been a clever way to ground out the
bridge plate and strings without having to run an extra wire (connect base
plate to pick up ground, thread height bolt into bridge plate and base plate,
create the connection, job done!)
Over the years, different materials have been used for the base plates,
starting with Zinc plated steel, moving to copper plated steel (both behave
near identically) and there have been experiments with brass of German/Nickel
silver too.
Base plates, honestly, don’t alter the signal a pickup creates by a huge degree
believe it or not (which gives some credence to the idea that they were solely
there to ground out the strings) – there’s something in it, but not much.
the Steel base plates, whilst not being “in” the coil, do contribute to the
iron content “around” the coil, and as such, ever so slightly increase the
pickups inductance, making it darker.
Brass, in comparison,
makes the pickup brighter (pushing the resonant peak up by around 0.5khz, but
it also attenuates the voltage at the peak, ever so slightly, which widens the
Q factor, so, even though the pickup is becoming slightly brighter, its also
becoming slightly less defined.
German Silver/Nickel sits right in the middle. If we’re comparing to steel base
plates because they’re “the norm” then it’s pushing the peak up a little higher
(by 0.2kHz) but its actually losing more voltage at the peak, so its brightening
and smoothing, but compared to brass, its smoothing a little more then its
brightening. It’s a nice tone in the right situation.
Ultimately, I like to think of base plates on the Telecaster® (and the Strat®)
as the salt and pepper on your steak. It’s not doing a lot, its that little bit
of seasoning right at the end, but, really, the meat (the coil and magnets) is doing
most of the heavy lifting. (Translation? If you don’t like your pickup with a
brass base, chances are you wont like it with a steel base either.)
String wrap
We don’t supply
the string to wrap around your coil, because, ultimately, its string! 2mm
diameter, cotton string. Comes in a billion colours, you use super glue to hold
it in place and it’ll be locked down by the time you wax bath it. Its string!
You don’t need me sticking the word “guitar pickup string” Infront of it and
charging you an extra couple of quid for the privilege.
I include it in this write up though, as a bit of a cautionary tale.
Do NOT wrap your string wrap directly to the coils. You’ll exert too much
tension on the coils trying to get the string tight, it will compress the
copper, and it will break. Get yourself some paper pickup tape (we will
shamelessly sell you paper tape with the word guitar in front of it, because
its low adhesive and specific widths!) and tape up the start and end of the coils
where they sit against the fiber boards, and then wrap the entire coil in tape
(I like 6mm tape for covering the fiber board wire and 15mm tape for the coils.
We do a multi buy discount too! 😉 )
Once your taped up, then get your length of 2mm cotton string, in whatever
colour you fancy, from whatever string supplier you’ve found, and super glue the
start of the string in place AWAY from the start and end wires. Make sure its
glued onto the tape, not the board or the wire. Slowly wrap the string around,
until you run out of space, trim it to length, tuck it into place, hold it down,
and add a little blob of super glue to the end. Your now stuck to your pickup,
but you’ve got a nicely wrapped bridge pickup with nothing messing with the
coils.
Conclusion
And I think,
for now at least, that about covers everything you’ve got to worry about when
it comes to building a Bridge pickup for a Tele® - there’s an awful lot of
variables, there’s an awful lot of stuff to consider beyond “how much copper shall
I chuck at it, but, really? Its not all that complicated when you break it
down! (Except pole diameter… but just remember “1/4” poles? You aren’t using 42
AWG!")
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