Pickup String Spacing – choosing a humbucker

 

Pickup string spacing is something you need to be aware of when you’re buying guitar pickups, particularly humbuckers. Guitar bridges come with different string widths so pickups need to match that. In this blog post I’m going to explain what It’s all about and how to measure it.

Table of Contents

What is a Pole Piece?

What you don’t need to know

Pickup String spacing – what you need to know

How to measure string spacing

What is F spacing?

What is a Pole Piece?

Pickups have pole pieces, think of these as magnets mounted in the pickup listening for string movement. Sometimes they are actual magnets, sometimes pieces of steel directing magnetism towards the strings. In this case they are steel screws.

This is what we mean by ‘pole spacing’ its the distance between the outer most poles, centre to centre.

What you don’t need to know

The way a pickup works is the string sitting inside the magnetic field actually becomes a temporary magnet and when it vibrates it disturbs this magnetic field and creates an electrical signal in the coil of wire around the magnet.

It’s a tiny signal but enough to get through your guitar’s on board circuit and down a cable to an amplifier. It’s hard to imagine that such a small amount of electricity can produce such a lot of sound. Have a think about it next time you’re at a big gig. What you’re hearing is just that small amount of electricity generated in a coil of wire. It’s really cool stuff and I find it fascinating. But you don’t really need to know all that.

Pickup String spacing – what you need to know

What you do need to know is that the string needs to align with the magnet to get the best signal. Magnets are, however, not lasers, they generate a magnetic field and not a precise beam. If the string isn’t in perfect alignment it’s fine. If the slightest misalignment made a difference then string bending would cause a drop in volume. Have a look next time you bend a string how far the string moves away from the pole.

As you can see, a little bit out of line makes no difference. Eddie Van Halen used a vintage PAF on Van Halen I with a Fender type bridge – the PAF ‘s were 49.2mm (1 15/16″) spacing and Fender bridges are usually 52mm. If there had been a problem he would have noticed.

Please remember that if a humbucker has 49.2mm spacing or 52mm spacing it’s outer dimensions are the same. The overall size of the pickup doesn’t change. So if you take out a 49.2mm humbucker and replace it with a 52mm it will still fit, it’s just the pole alignment to the strings that will be different.

Guitar bridges come in various sizes giving different string spacing. So if you have a Gibson ABR Tune-o-matic your string spacing will be narrower than a Fender Strat bridge, for instance.

By the time the strings get to the neck pickup the spacings are just about the same so neck pickups don’t vary in width. We’re just talking about bridge pickups here.

So we really want the strings to line up as best as possible with the pickup’s poles but we’re not getting too hung up on it.

How to measure string spacing

The measurement is the distance from the first to the sixth strings centre to centre at the bridge pickup. This diagram should help:

You can simply do this with a ruler, like I have.

As you can see this ’89 Strat bridge has 52mm string spacing. If you wanted to choose a bridge humbucker to make it a HSS Strat than choose the 52mm option.

If you’re buying a Mr Glyns Pickup and have any doubt just send me a pic of your bridge and I should be able to advise you.

What is F spacing?

F spacing simply means a wider spaced bridge humbucker – 52, 52.5 or 53mm. The F stands for either ‘Fender’ or ‘Floyd Rose’. It isn’t clear which and doesn’t really matter.

Why 49.2mm not just 49mm? You may well ask! It’s the metric equivalent of the pole spacing for a Gibson PAF which is the pickup most humbuckers are based on. The original measurement in imperial is 1 15/16″ – which if you ask me is no less silly a number that 49.2 but we’re stuck with it.

If this has given you a need for a new set of humbuckers you can find the Mr Glyns Pickup humbucker range here.

Here is a link to my YouTube playlist for humbucker demos.

Bellbird - vintage Strat pickup set

 

The Stratocaster has been around since 1954 and the legend continues. Reading the internet (!?) tells me there have been good and bad years or decades, guitars to avoid and ones worth hundreds of thousands of dollars. I’ve been repairing guitars since 1995 so I’ve played a lot of old Strats and analysed a lot of old pickups. Vintage pickups aren’t all great but the good ones are fantastic.

I’ve based my Vintage Strat set on the best of the old pickups I’ve had the pleasure of playing through . So I use AWG42 heavy formvar insulated wire – there’s something about the thickness of that insulation that just works with an old Strat pickup.

I’ve aimed for that old quacking chime that makes Strats wonderfully percussive but with a singing quality that’s so musical. Warm and clear with beautiful almost reverb-like clean tones – that’s what I want out of an old Strat. The neck needs to be fat, round and clear, the middle pickup needs to quack and the bridge a cut through twang without thinness. The all important ‘in between’ sounds in positions 2 and 4 must be balanced and characterful. Nothing says Strat more than these sounds.

The Bellbird set has been designed mainly for clean tones but they’re certainly not afraid to perform with a bit of gain. As part of a HSS set they’re great with one of my ‘Integrity’ humbuckers in the bridge position.

I agonised for months over names for my Strat pickup sets then during a camping trip to Tauwharanui Regional Park I heard my first Bellbird and realised that was the sound I had been looking for when I was designing this set. The comparison in tone between the Bellbird and the more common Tui seemed exactly what I had in my head when designing my Strat pickups. Bellbirds don’t just go tweet, there’s a depth and warmth in the tone. It’s so hard to describe sound and the difference between pickups but I think the difference between the Bellbird and the Tui sum up the difference between my vintage and hot Strat pickups. So I called them the Bellbird and the Tui.

These sound samples should show you what I mean:

Bellbird:

Tui:

Here are some sound samples recorded clean through a Fender Princeton Reverb-Amp. The overdrive sounds are using an Electroharmonix Soul Food. The guitar is an Alder body Strat with rosewood fretboard strung with D’Addario 10-52’s. All of them with the same guitar, same amp, same settings, no reverb or eq added later.

Bellbird Neck Pickup Clean

Bellbird Neck and Middle Pickups Clean

Bellbird Middle Pickup Clean

Bellbird Middle and Bridge Pickups Clean

Bellbird Bridge Pickup Clean

Bellbird Neck Pickup with Overdrive

Bellbird Neck and Middle with Overdrive

Bellbird Middle with Overdrive

Bellbird Middle an Bride Pickups with Overdrive

Bellbird Bridge Pickup with Overdrive

https://www.youtube.com/c/MrGlynsPickups/videos

Stratocaster Pickup re-wind.

A customer brought me a 'dead' Strat style pickup the other day. It's out of an 80's Yamaha but its identical to a Fender in design.

I see quite a few old Fender pickups that have suddenly started to sound thin and quiet. It's a common problem, the insulation breaks down over time shorting out the pickup. 

The fate of this pickup was sealed when it's owner decided to adjust the pole piece height. It has the vintage style staggered poles, they are not adjustable, if you push them in it will sheer of a load of wires and kill the pickup. 

I like pickups, I like rewinding them. It's such simple high school physics but so fundamental to electric guitars.

 A pickup is simply a magnet with a coil of very thin wire wrapped around it. If you pass something ferrous through the magnetic field (a vibrating string) it disturbs the field causing electrons in the coil to move - that' electricity. It's not much electricity but amplify it a couple of times and you've got stadium ROCK. Cool eh.

To make a pickup sound good is rather more complicated, in fact, rather surprisingly so considering the basic principle is straight forward.

I tested the pickup and the meter showed it was dead. Before snipping all the windings off I just re-solder the wire terminals just in case of dry joints, this does sometimes fix it , worth a go.

In order to re-wind it I need to cut off the old windings. The wire is as fine as hair (I'm judging by my own) and there are thousands of turns of it. I'm careful not to damage the bobbin while doing this. Any little nicks can catch on the new windings and ruin an otherwise good rewind.

The old windings are off now and you can see what happened.
The two highest pole pieces that were pushed down have torn the protective tape and sneered off some of the turns.

You can see what a simple structure a Fender pickup is. Each of the 6 lugs is an alnico magnet press fitted into vulcanised fibre board. I use a blade to scrape off any excess wax and smooth out any high points.

 I seep very thin superglue into the magnet/fibreboard joints just to be sure it's all still strong.

I replace the tape with some thinner stuff. The tape increases the life of a pickup by preventing the inner windings from shorting out on the pole piece. I use really thin tape to keep the inner windings as close as possible to the magnet. There's a lot of high end clarity that comes from these inner windings. This pickup is ready for the winding machine.

I mount the pickup to the machine with an extra little block to keep the underside straight. Some vintage pickups can get a bit bendy without this support when winding.

I anchor the wire by wrapping it through the lug 4 or 5 times.

 I prefer to wind with a combination of scatter winding by hand and machine winding. I've tried so many different ways over the last 20 years, this works best for me.

Here's the finished coil. You can see it looks slightly uneven, that's intentional. If you wind a pickup too neatly it sounds a bit dull. An element of randomness creates a loose, open clarity. 

I've wound this one with 8500 turns of 42AWG wire. It's come out at 6.2 KOhms which was about what I wanted. This is a bridge pickup and the other two are 5.6KOhms wound with the same gauge wire. So it should match in well.

I wax pot it to prevent micro phonic feedback

 And we're done - this Strat pickup lives to ROCK another day

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Feel free to contact me, mrglynspickps@gmail.com