Concern on pickup selection

[PhatBoi5]

Im getting a custom bass thats going to be a 5 but strung like a 7 with an F# on bottom. My question is would i run into any problems with using a standard jbass pickup?

[joelb79]

No problems, as long as the pickups fit and the poles are over the strings. I get the feeling your not changing the bass from its current function, only changing the tuning and strings. This is more a setup issue than electronics issue. The nut will need to be widened to accept thicker strings, and you will need to likely loosen the truss as thicker strings will put more curve/pull into the neck. You also might need to lower the pickups on the bass side because the new strings will have more movement over the coil, but this might not need to be done if the setup is correct already and the truss/nut/string action are proper. But as long as the bass was 5 string before and the pickups were 5 string, you should have no problems altering the tuning and sizes of your strings; with the above setup issues being cared for.

[PhatBoi5]

This is a bass that is going to be built for me. Im going to use cocobolo for the nut and bridge so it will be spaced to accommodate the string set up. Just wondering if i used, say a SD basslines soapbar for a standard 5, would the size difference in the strings not be in the intended magnetic field for said pickups....if that makes sense

[joelb79]

No the magnetic field needs to fit the bass's string spacing. The wider string spacings at the bridge would need coils that have magnets over the strings. When the spacing at the bridge is 16.5 mm, this requires on magnet spacing on the pickup vs 19mm bridge spacing. Also the nut spacing plays into this as well for the neck pickup.

Duncan makes two different spacing's and sizes of 5 string jazz pickups that I will use as an example.

The first pickup is designed for more narrow spacing 5 string basses. These are listed as a 67-70mm total string width pickup. There would be 4 spaces inbetween that total spacing, which means they can be used with a bridge string spacing of 16.75-17.5 between strings (70 divided by 4).

Neck pickup:


Bridge pickup:


Larger spacing pickup has been widened, because the magnetic field needs to extend further to cover the width of 70-74mm (up to 19mm between strings) total string spacing. Duncan say "Calibrated neck and bridge set. Comes in two popular string spacings: 67 mm neck with 70 mm bridge, and 70 mm neck with 74 mm bridge."

much like this 5 string 1/4 pounder pickup.



Duncan says:

This pickup is a direct retrofit for Fender® Jazz V and many other popular 5-string basses. Will accommodate string spacings up to 3.10" (78.7mm) for bridge pickup and 3.00" (76.2mm) for neck pickup

This means it is the larger sized Jazz pickup made for string spacing up to 19mm at the bridge. That is a wide pickup.

When the pickup has a bar magnet, the only consideration you need to know is what EMG says. This is taken from their 4/5 string J Set pickup manual:

Both SJ and LJ Housings can work with both 4 and 5-string instruments, but you should check the width of your strings against the magnet dimensions above to make sure there is sufficient string coverage. A rule of thumb for any pickup is that the total magnet width should be the string width plus twice the distance the pickup is from the strings. So, If the pickup is 3/16” (5mm) from the strings, with a magnet width of 3.10“ (78mm) the maximum string width would be 2.72” (69mm).

That is a great rule of thumb for a bar magnet pickup.

But for the pickup your choosing a SD Basslines soapbar for a 5 string; then



The maximum string length is close to 80mm. Essentially, that will work with any string spacing on a 5 string to 20mm at the bridge. No you don't need any other considerations than that. That pickup will work without changing any plans you already have in place.

Hope this helps explain string spacing and magnetic field a bit.