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Understanding the ’72 Fender Mustang Bass Pickup Design

The ’72 Fender Mustang Bass Pickup may appear to be a budget model but Leo Fender cared about his products and everything was thoroughly thought out.

A bit of history

I get to repair old pickups as well as make new ones so when I was sent this old Mustang Bass Pickup I thought it was worth taking a few pics and writing about it.

This was the last bass designed by Leo Fender before he sold Fender to CBS in ’65. This pickup shows all the thought and consideration you would expect from the great man. It’s easy to dismiss pickups on ‘budget’ guitars but there’s a lot more to this one than meets the eye.

The later version of this instrument, the Musicmaster Bass had a single coil pickup straight out of a Stratocaster – yes really. Here is more on the Musicmaster bass pickup. I make my own version of the Musicmaster bass pickup in two flavours.

The original Mustang bass pickup that I have here is a split pair, like a precision bass pickup but with a few essential design differences.

Mustang Bass Pickup

What makes the Mustang Bass Pickup great

The obvious thing is that it’s smaller, but there’s a good reason for that.

The Mustang is a short scale bass, 30″. With a shorter scale comes less string tension and a much boomier sound with less percussive highs and a fatter bottom end.

So why didn’t he just use P Bass pickup?

It’s obvious from the design of the Mustang Bass Pickup that the intention was not to just knock out a cheap student model but to make a great instrument only with a shorter scale.

'72 Fender Mustang Bass Pickup

You can see that the magnets are protruding out of the bottom of the base plate – they’re 24mm long alnico 5 magnets. P Bass magnets are around half that length. Bigger magnets means more pull on the string and more punch to the attack of the note.

The distance between top and bottom plates is greater on the Mustang than the P Bass. This gives a much taller pickup. With a taller pickup more of the windings are closer to the magnet. A P Bass’ windings can get a lot further away from that magnetic field by the time you get to the outside turns.

Windings closer to the magnet gives a sharper, more percussive mote than the mellower P Bass.

With roughly the same turn count between P Bass and mustang this means the Mustang’s footprint is smaller.

Both those factors – coil geometry and magnetic pull are specifically designed to offset the lack of definition you can hear in a short scale bass.

This was not the easiest path to take. The magnets would have to have been specially made and the flatwork (top and bottom plates) would have been made specifically for this model. Not least there would have been molds made to injection mold the covers.

It was all about getting the best possible sound from a short scale bass while make the price accessible to more musicians.

It’s a clever design.

Five years later when CBS were running Fender they introduced the same bass but with a Stratocaster (yes, 6 pole) pickup. Now that was taking the easy route. Leo Fender always did things the best way he could, working up to a standard rather than down to a price.

If you’re interested in Leo Fender read Forrest White’s book, he was there.

So back to the Mustang Bass Pickup repair

As you can see from the colour of the windings the wire has plain enamel insulation. The insulation does make a difference. Not all insulation is the same thickness. Thicker insulation means windings are further away from each other. This changes the pickups capacitance and to an extent inductance and dc resistance. Remember, we’re multiplying small differences by how many turns there are, in this case over 10,000.

It appears this coil failed due to corrosion of the magnetic pole

You can see the corrosion in this pic.

In the 70’s Fender pickups were potted in lacquer rather than wax in both earlier and later periods. The lacquer didn’t penetrate all the way to the core of the pickup and this is the result.

Before I re-wound this coil it was rust proofed and insulated – I want this repair to outlive me.

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Musicmaster Bass Pickup

Single Musicmaster Bass Pickup– NZ$165 for NZ customers, if you’re overseas it’s GST free; NZ$143.48

Alnico V – 6.8 kOhms – ’51 Telecaster Bass spec

Or Alnico V – 5.7 kOhms – Original ‘70’s Strat spec

From its humble beginnings the Musicmaster Bass has become a classic. Beloved of Indie bands, studio engineers and offset fans. The Musicmaster Bass has begun to make its way in the world and leave its mark on music.

Musicmaster Bass pickup by MrGlyns Pickups
Musicmaster Bass Pickup

The Problem with the Musicmaster Bass Pickup

Designed originally to be a ‘student model’ short scale, Fender cut quite a few corners to reduce the cost. This was the 1970’s and the accountants had a big say at Fender. This was an instrument made down to a price not up to a standard. But despite the obvious cost cutting I still have a soft spot for the Musicmaster. They were cheap but that doesn’t mean they weren’t good.

The basic bones of the Musicmaster are good. Short scale bass with a small body makes a lot of sense. But there was a problem with the pickup.

Rather than design a pickup specifically for this guitar Fender instead used a Stratocaster. Then they hid it inside a blank cover.

Here is the problem with using a Stratocaster pickup with a 4 string bass. The red lines are the strings and the black dots are the pickup magnets.

Fender Music Master magnet alignment

It’s pretty obvious that the magnetic pole pieces just don’t line up with the middle strings.

The pickup wasn’t visible under that blank cover and they decided it didn’t matter on a budget bass anyway. So that’s how it was.

The Solution

In July 2024 I was contacted by my Neville Claughton from Nelson. He had an original ‘73 in need of a new pickup.

Nev is a legend in NZ, he’s been well known in the music business for ever and I have huge respect for him.

His request got me thinking so I decided to make my own version of the Musicmaster pickup but with 4 poles that line up with the strings.

I got on the computer and designed this pickup flatwork to be laser cut. As you can see it’s simply a 4 pole Strat pickup.

flatwork design for Musicmaster Bass by MrGlyns Pickups

The only difference is those pole pieces.

And here is the spacing of the poles on the Mr Glyn’s Pickup. You can see how the magnets line up with the strings.

String and pole alignment for MrGlyns Pickups Musicmaster Bass pickup

I’m happy with that.

Winding the Musicmaster Bass Pickup

So how was I going to wind this pickup?

There’s nothing wrong with the windings of a ‘70’s Strat pickup. With the reduced string tension of a 30inch scale bass there is a tendency for it to get boomy, so having a pickup with less inherent bottom end can help with clarity. It really isn’t a bad sound. My personal preference for these instruments is to have the Strat pickup specifications but with, of course, the correct string spacing.

But there is scope for having different winding options.

If you want more fatness in your tone I also offer this pickup with my ‘51 Telecaster Bass wind. This gives a bit more power but also more bass. This option still has the same Strat footprint and fits inside the same cover.

So if you want a fatter tone for your Musicmaster then this is your best option. Here’s a demo of that pickup.

Both winding options have the same footprint and the same alnico V magnets, it’s just the amount of windings that’s the difference.

This pickup is available with 3 cover options: black, white or cream.

Musicmaster Bass pickup covers by MrGlyns Pickups
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Updated May 2025

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