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Is my bridge pickup wide enough?

DaveAceofBass

DaveAceofBass

Feb 20, 2004
5,145
1,863
Charlotte, NC
fandalism.com
#1
I have a custom Kinal SK5. The bridge pickup is a Bartolini MM pickup, a custom version of the pickup Mike Kinal uses. I've always been concerned about the pickup not being wide enough, but I don't notice any sound dropout on the B or G strings when I'm on the neck coil (60s J position) or in parallel humbucking mode. However, I seem to have pretty low output when I'm on the bridge coil (70s J position) side. Although I don't really notice a dropout on the B or G strings, it is noticeably lower output compared to the front coil. I'm thinking of replacing the pickups, but that may require routing, which I wouldn't want to have to do to my sweet bass.

Take a look at the picture and tell me what you think!

DSC02824.jpg
 
#3
Looks to me that the B and G strings are on the very edge of the magnetic field and will be a taste low, output wise. I'd guess it's a four string PU.

If it has a bar type pole piece instead of individuals may not be as unbalanced as it looks.

Neck PU isn't quite as bad due to the string angle but I think it's a 4 string PU, too.

mech
 
#4
DaveAceofBass said:
...I don't notice any sound dropout on the B or G strings when I'm on the neck coil (60s J position) or in parallel humbucking mode. However, I seem to have pretty low output when I'm on the bridge coil (70s J position) side. Although I don't really notice a dropout on the B or G strings, it is noticeably lower output compared to the front coil.
Click to expand...
this means the pickup by definition is indeed wide enough.

the back coil being weaker than the front coil is a different issue entirely. how close is the pickup to the strings?
 
#5
The rear coil will be somewhat quieter as it's an inch or so closer to the bridge- the string vibration is less and less the closer you get to the bridge. If this bothers you, you could compensate somewhat by tilting the pickup to bring the rear coil closer to the strings- adjusting the two screws on the B side should accomplish this.
 
#6
If you get good volume on the B and G string with both pickups then you are good to go.

This is the problem the infamous Rickenbacker 4004cii5 had. The B and G strings were noticeably quieter than the middle 3 strings.
 
#7
dmusic148 said:
The rear coil will be somewhat quieter as it's an inch or so closer to the bridge- the string vibration is less and less the closer you get to the bridge. If this bothers you, you could compensate somewhat by tilting the pickup to bring the rear coil closer to the strings- adjusting the two screws on the B side should accomplish this.
Click to expand...

+1. Totally.
 
#8
Thanks for all your input. Is there any way to test the output of the B and G, aside from using my ears? Is there a meter that will read this? Should I get some of that magnetic paper that allows you to see the coils?

Bartolini's site has some info on this:
Invalid Link Removed

While my ears think there's no reason to worry, my brain is concerned.

I asked Mike Kinal about this, his reply was:

"The back pickup should be fine as far as string spacing 74 mm from the center of the B and the G string over the pickup."

I think what he means is if the total string width from the center of the B to the center of the G string is 74mm or less, it will be fine and not to worry. Since the string spacing at the saddles is 19mm, it would be 76mm across all five strings, and it should be fine given the 2mm difference would be compensated for as the strings gradually taper together toward the nut. Even so, the outer strings are clearly very close to the edge of the magnetic field. But again, I don't hear any dropout, so I guess I shouldn't be concerned...right?

One other note... The pickup is 3.98", which is Bart's 4/5 string MM pickup. I think it is meant for either 4 or 5 string. They make a wider pup, like for the Laklands. However, I recall that the early Laklands also had a narrower bridge pickup. I guess there's no cause to worry.
 
#9
DaveAceofBass said:
But again, I don't hear any dropout, so I guess I shouldn't be concerned...right?
Click to expand...
by definition, yes.

what happens is, humbucker-type pickups with one big bar magnet actually have a field that bulges a bit at each end of the bar; even if the outer strings hang over a pinch, the bulge "catches" them anyway, so there's no issue.
 
#10
walterw said:
by definition, yes.

what happens is, humbucker-type pickups with one big bar magnet actually have a field that bulges a bit at each end of the bar; even if the outer strings hang over a pinch, the bulge "catches" them anyway, so there's no issue.
Click to expand...

Thanks! I've also noticed that the Bart catalog doesn't show larger MM pickups, but I know they make them. Other Kinal 5-string basses with J/MM pups seem to have the same size bridge pup.
 
#13
I've listened carefully. The B string does drop out a bit when I pull hard, and I don't think it's as full as the A and D strings. I obviously am going to have to replace the pickup and route for a larger one. So now I have to decide what to replace it with. Some considerations are Nordstrand, Legacy Lane Poor (if they ever contact me back), or Kent Armstrong. Any suggestions?
 
#15
Many Bartolini pickups have pole pieces shaped like a T. So even if the coil doesn't extend to the very edge, the pole piece will. The fact that this pickup is sensing the strings evenly shows it's wide enough.

But half a MM humbucker is not the same as a Jazz pickup. The Jazz pickup is wound hotter. Pickups installed at the neck are also louder than the same pickup installed at the bridge. Many winders, including myself, wind the bridge pickup hotter to compensate.

Also check your Bart's two coils and I think you may find one is wound hotter. His classic bass series, as did the old Hi-A pickups, are wound with unbalanced coils. This gives a more open sound. On mine the coil closer to the bridge was hotter, but he might have changed it.

I'd also try the MM in parallel. You may get a little more oomph from it because it will having more total windings, and is sensing a wider area. It's not an identical sound as in single coil mode, but is often very close.
 
#16
SGD Lutherie said:
Many Bartolini pickups have pole pieces shaped like a T. So even if the coil doesn't extend to the very edge, the pole piece will. The fact that this pickup is sensing the strings evenly shows it's wide enough.

But half a MM humbucker is not the same as a Jazz pickup. The Jazz pickup is wound hotter. Pickups installed at the neck are also louder than the same pickup installed at the bridge. Many winders, including myself, wind the bridge pickup hotter to compensate.

Also check your Bart's two coils and I think you may find one is wound hotter. His classic bass series, as did the old Hi-A pickups, are wound with unbalanced coils. This gives a more open sound. On mine the coil closer to the bridge was hotter, but he might have changed it.

I'd also try the MM in parallel. You may get a little more oomph from it because it will having more total windings, and is sensing a wider area. It's not an identical sound as in single coil mode, but is often very close.
Click to expand...

Thanks for the info. Even though the B string is being sensed, I think there is a bit of drop out that is more noticeable when I play really hard. I'm debating what I should do at this point. Your comments on the switch got me thinking...I wonder if the switch is set to neck coil/series/bridge coil. I think that's the case. Maybe I'll have my tech rewire it so that there is a parallel position instead of the bridge coil. If that really works and sounds good, I may switch the neck pickup from the Bart CBJD to a 59J1. I'm still not sure...Kent Armstrong, SGD, Legacy Lane Poor, and Villex are options for replacement pickups, but I may try rewiring the switch, replacing the neck pickup, and switching to an Aguilar OBP-3 first (if I can afford it).
 
#18
Well, it's definitely NOT wide enough. The B string sounds good, but not as full as the others. Definitely on the edge of the magnetic field. I'm going to rout and put in Nordstrands, the MM5.4 and NJ5SE for reduced treble (the preamp has tons of highs). That is, unless Kent Armstrong or another blade pickup maker can make an exact replacement with blades that go ALL the way to the edge, and can cover my 76mm string spacing... If that is a possibilty, I can avoid routing.
 
#19
DaveAceofBass said:
While my ears think there's no reason to worry, my brain is concerned.

I asked Mike Kinal about this, his reply was:

"The back pickup should be fine as far as string spacing 74 mm from the center of the B and the G string over the pickup."

I think what he means is if the total string width from the center of the B to the center of the G string is 74mm or less, it will be fine and not to worry. Since the string spacing at the saddles is 19mm, it would be 76mm across all five strings, and it should be fine given the 2mm difference would be compensated for as the strings gradually taper together toward the nut. Even so, the outer strings are clearly very close to the edge of the magnetic field. But again, I don't hear any dropout, so I guess I shouldn't be concerned...right?

One other note... The pickup is 3.98", which is Bart's 4/5 string MM pickup. I think it is meant for either 4 or 5 string. They make a wider pup, like for the Laklands. However, I recall that the early Laklands also had a narrower bridge pickup. I guess there's no cause to worry.
Click to expand...

For the 4 string size MM pickup, Bart states:

"String width covered is 66mm to 73mm on medium curvature fingerboards"

So unless that is a custom Bart, that seems too narrow. It might sound balanced however, since the two outside strings are closer to the pickup. If it sounds fine, than it's OK. Personally I wouldn't use pickup that's narrow on that bass, especially since longer (wider) pickups are available.

They do show the wide 5 string MM with the tabs in their size chart, and they make the 5 string MM without tabs.
 
#20
If you're getting an overall volume drop on the bridge side coil, it's only because being that close to the bridge there is less string excursion and therefore less signal generated.
 

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