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Modding 4 string jazz pickup for 5 string. Possible ?


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  • 3 weeks later...

I'd imagine it'll depend on the strength & shape of the magnetic field to start with, the magnetic properties of the added metal strip (what it's made of, it's shape, it's position in the field) and of most importance - the string spacing you want it to work with vs the magnetic properties of the modded pickup.

I'd say the pickup type will be a big influence - e.g. the Entwistle pickups you're looking at are "Neos" or Rare earth magnet based - that almost always means the pickup poles are not charged magnets, rather like a typical ceramic magnet there is a bar or bars of magnetic material on the underside of the pickup poles - thereby magnetizing them. In short you won't know till you start modding, but I'm guessing a thin ceramic magnet slightly over the width of the strings would probably get fairly even output over the 5 strings - but it would change the voicing of the pickup significantly. A piece of Iron (Steel really) or another ferromagnetic alloy (e.g. [url="https://en.wikipedia.org/wiki/Alnico"]AlNiCo[/url]) as long as it's not charged with it's own noticable magnetic field will probably do a lot less to change the voicing of the pickup - but I'd say you're more likely to have output issues across the strings - especially if you have a pickup that has staggered pole pieces that doesn't match the radius of the 5 string fretboard. Many pickups allow some adjustability thank fully - otherwise I guess you could just run it through a compressor!

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Thanks for replying. Went ahead with the job last Saturday,

I scrapped the Entwistle idea and went for a couple of 6.5 jazz pickups,knew I was going to butcher them to fit. As it turned out once I'd removed
the covers the bobbins needed cut too,then packed into the new RW covers.

A 2 band EQ got fitted at the same time. The neck pickup is working beautifully but there's a distinct drop on the bridge one.I'm hoping the bobbin
has moved inside the cover or maybe the height needs raised.The covers' screws may have caught the wadding.

It's been slightly awkward this one as the bass is a Peavey Zephyr or C5,the only pickups I know of that nearly fit are EMG soapbars costing more than
the bass is worth :) So it got singles nestled in rosewood instead :)

As things stand it's a marked improvement from when I got it,snapped Vol and humming like crazy.Still have a "Tonewood" cavity cover to cut so I'll check
the pickup tomorrow,there's hoping it's an easy fix ;)
[attachment=224257:Zephyr Rosewood.jpg]

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Wow - I just saw the title and thought it was interesting - as it had no replies I assumed it was a new thread!

Still better late than never. Glad you've got good results, those pickup covers look great with the matching fingerboard! Certainly an improvement over matt black covers!
FWIW pickup height & biasing (in the case of an active blend circuit) is always a compromise on a two pickup bass. The bridge may need to come up - but the neck may need to come down :( - if the pickups are to play nice together.

Of course if you go down the Billy Sheehan or "Rick-O-Sound" route, with a seperate output for each pickup, it's another story!

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Sadly my hopes for either a turned pickup or pushed down one were dashed :(

Raising slightly helped but it's competing with that fantastic sound coming from the neck :lol:
I A/B/C'd it against a Grind & International. The International suffered the same drop with bridge pickup solo'd,
no difference between the two on the Grind.

If as I suspect it's the same pickups in both Zephyr and Grind the International will get the Zephyr ones,the rout is the
same size :) Now that I've tried to the idea of using a 4 string pickup with some success I'll try a different one.

Wish me luck.

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Spoke to a lad that builds pedals. He suggested swapping the blend pot,he could be on to something.

10 o'clock is bridge,12 o'clock massive jump as the neck comes in. That can't be right.

It's got me baffled. There's no drop across the strings so the pole pieces are lining up,Peavey used the same pickup in both 4 and 5 strings models.
The pickups were a set so by rights should both have the same magnets. The preamp is working.

There's a Blade pickup on it's way so I'll be trying that. Probably no this weekend but the one after before it'll get done.

Thanks for the input folks it's appreciated.

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Nearly solved the problem :)

A Warman Jazzbar pickup arrived yesterday. Popped it out the cover and trimmed it down to fit.

[attachment=225014:Zephyr pickups (2).jpg]

And here it's in it's new home.

[attachment=225015:Zephyr pickups (1).jpg]

Very snug fit :)

Soldered it last night and am happy to say there's equal output between neck and bridge.

The volume drop has now moved to centre dent :lol: A new balance pot arrived this morning so will be going in tomorrow.

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Knew I should have taken a before/after photo :)

The Warman had some packing inside it's cover so it was snug before sealing. There was some between the coils
and at both ends. It was a very light paper like shops wrapped jewellery with.

The trimming was just the glue. The original single coil had excess plastic each end of the reel removed,none of the wires
were disturbed.

Tell you what the Warman is a great pickup,very happy with it.

Still no progress on the centre dent volume drop :(

Wiring is Neck red to centre lug on balance, bare to ground on tone pot
Bridge is Red/White to centre lug on balance, black/bare to ground. That's the standard wiring as per Warman site.
There's a green which is hot but I don't see where it'd go to stop the drop.

If it was lousy solder joints output would be affected either way but now it only happens when both pickups are on full.
I've also ordered a Linear b500k pot instead of a M/N 500k.

Think it'll make much of a difference ?

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