Pole piece adjustment on a jazz bass

[mickebas]

I just got a new Sire V7 and overall it seems to be a good instrument for the money spent.
I have one big issue though and that’s a common j-bass problem. The E and G strings have significantly more outout than the middle strings. I’ve tried to adjust pickup height and raised the outer strings as much as I find possible. Also I lowered the pickups so that there is a pretty big gap between the strings and the pole pieces.
But it still doesn’t make the instrument playable as far as decent string to string balance and now I’m thinking about lowering the outer pole pieces by mild force (press them down). I have done that succesfully before when I wasn’t as aware of the risk and it turned out a good thing with better balance.
I’ve heard that the risk of damaging the copper wire of the pickup is smaller when doing to the outer pole pieces.

I know this seems like a long story trying to justify me doing this and it kind of is...
Anybody else out there in the bass community that has insight in this J-bass problem and has solved it in a similar or other way?
I know of the DiMarzio J’s with adjustable poles of course but I’m really not after that sound now, I have them on other basses.

 

[RobbieK]

It depends entirely on how the bobbin is designed. You'll need to remove the pickups, then covers of course, and have a good look.

If they are traditional fender style bobbins with two pieces of fibreboad flatwork pressed directly onto the magnets, then it's most likely that the winding wire is wound directly onto the poles, with only a piece of tape (or less!) between them. Trying to shift these poles will be very risky.

OTOH, if the bobbin looks like it is moulded from a single piece of (abs) plastic, there's a very good chance the poles are pressed into individual tubes that join the top and bottom. In which case, pressing the poles poses very little risk.

If they have ceramic magnets underneath and steel poles, you would have to remove the magnet and then the poles. After this you'd have to shorten the outer poles. The magnet has to have good contact with the bottom of each pole piece.

If they are alnico poles, another option would be to add small neo magnets to the underside of the inner poles. Use ones that are the same diameter as the poles, and perhaps 2 or 3mm in height. This will boost the magnetic field slightly above the pickup in that area.

 

[mickebas]

It depends entirely on how the bobbin is designed. You'll need to remove the pickups, then covers of course, and have a good look.

If they are traditional fender style bobbins with two pieces of fibreboad flatwork pressed directly onto the magnets, then it's most likely that the winding wire is wound directly onto the poles, with only a piece of tape (or less!) between them. Trying to shift these poles will be very risky.

OTOH, if the bobbin looks like it is moulded from a single piece of (abs) plastic, there's a very good chance the poles are pressed into individual tubes that join the top and bottom. In which case, pressing the poles poses very little risk.

If they have ceramic magnets underneath and steel poles, you would have to remove the magnet and then the poles. After this you'd have to shorten the outer poles. The magnet has to have good contact with the bottom of each pole piece.

If they are alnico poles, another option would be to add small neo magnets to the underside of the inner poles. Use ones that are the same diameter as the poles, and perhaps 2 or 3mm in height. This will boost the magnetic field slightly above the pickup in that area.

Thanks!
Impatiently I took the risk (as done before) and cautiously hammered the outer poles down without removing the pickups. Luckily it seems to have worked out this time too though I’m aware it’s not something you’d recommend on a more expensive bass and pickups.
Now I have much better string balance and since I’ve gotten more and more aware and perhaps fixated with that over the years it made the bass playable and that had to be top priority worth taking the risk to achieve.

 

[walterw]

I’ve heard that the risk of damaging the copper wire of the pickup is smaller when doing to the outer pole pieces.

oh lord no

it's the exact opposite, if the coil is wound directly on the magnets you should only risk it on the inner poles!

 

[mickebas]

oh lord no

it's the exact opposite, if the coil is wound directly on the magnets you should only risk it on the inner poles!

Ooops!
Well, everything turned out good this time and the bass is now playable
I can’t help wondering after + 40 years as a J-bass player, why the pole pieces does not follow the radius. I’ve never encountered a jazz bass that doesn’t have a too loud E- string and a weak D-string. This must be well known by now and still I have the same problem every time.

 

[walterw]

I can’t help wondering after + 40 years as a J-bass player, why the pole pieces does not follow the radius.

agreed, just because the original was that way why are all the newer ones that way?

 

[IPRAYB4IPLAY]

Cool now that you have a even tone output with all your strings you can also adjust your trust rod clockwise to obtain more output and tone. Only turn that trust rod maybe 1/4 inch turn until you get the desired sound you want and if it has 2 trust rods they must be turned evenly and you can slightly raise the G and E end of your pickups just a little so those 2 string tones and volume will be more equal to the E and A strings volume. Obviously if your G strings diameter is a 45 then its further away from the pole pieces than the E string at 135, 130, or 125 depending on the height of your bridge saddles.

 

[ctmullins]

Cool now that you have a even tone output with all your strings you can also adjust your trust rod clockwise to obtain more output and tone. Only turn that trust rod maybe 1/4 inch turn until you get the desired sound you want and if it has 2 trust rods they must be turned evenly and you can slightly raise the G and E end of your pickups just a little so those 2 string tones and volume will be more equal to the E and A strings volume. Obviously if your G strings diameter is a 45 then its further away from the pole pieces than the E string at 135, 130, or 125 depending on the height of your bridge saddles.

Wrong. So wrong.

The purpose of the truss rod is to control the amount of bow in the neck. That’s it. That’s all it does.

String gauge is likewise not relevant here.

Where do you get your information?

 

[IPRAYB4IPLAY]

You run your S%$# like you want and I wasn't talking to you anyway

 

[ctmullins]

You run your S%$# like you want and I wasn't talking to you anyway

It’s a public forum, and I feel compelled to correct potentially damaging misinformation, lest others suffer from it.

Where do you get your information? Mine comes from years of study, research, and experience.

 

[walterw]

you can also adjust your trust rod clockwise to obtain more output and tone.

Yeah no, sorry.

You adjust the truss rod until the neck has the right relief for playability, period.

That said, I think a straighter neck does have better resonance and sustain than one with a lot of bow, but that’s a happy side effect not the goal.

 

[PawleeP]

Wrong. So wrong.

The purpose of the truss rod is to control the amount of bow in the neck. That’s it. That’s all it does.

String gauge is likewise not relevant here.

Where do you get your information?

not relevant where? regarding string gauge or pole adjustments?

 

[walterw]

String gauge is likewise not relevant here.

not relevant where?

yeah, i'll have to push back a little bit here too. as i understand it some popular string gauges for both guitar and bass that seem kind of unbalanced tension-wise were originally created to try and balance the output through the pickups; most 4-string bass sets are tighter in the middle two than the outer two, possibly as a result of making the middle pair larger to try and make up for their increased distance with jazz basses.

hate the idea myself, i want the strings to feel even all the way across and then have pickups under them that sound even all the way across. (for me that's a "balanced tension" set with thinner middle strings and a bumped up E, 45-60-80-110, over a P pickup that i can of course angle to be perfectly even or over raised center-pole J pickups.)

 

[ctmullins]

My point (and sorry for not being more descriptive earlier) is that the gauge of the string has nothing to do with how close it is to a pickup pole piece.

 

[PawleeP]

yeah, i'll have to push back a little bit here too. as i understand it some popular string gauges for both guitar and bass that seem kind of unbalanced tension-wise were originally created to try and balance the output through the pickups; most 4-string bass sets are tighter in the middle two than the outer two, possibly as a result of making the middle pair larger to try and make up for their increased distance with jazz basses.

hate the idea myself, i want the strings to feel even all the way across and then have pickups under them that sound even all the way across. (for me that's a "balanced tension" set with thinner middle strings and a bumped up E, 45-60-80-110, over a P pickup that i can of course angle to be perfectly even or over raised center-pole J pickups.)

Thanx ww, Do you know if anyone has successfully adjusted the inner poles on an sjb1. I have already tried it on a few fender jazz pups and ruined them. rekon maybe i should have read more threads first and or tried heating them pup a little with a hair dryer. Not sure if that would have loosened the apparent vulcanizing.

 

[Nickthebass]

Coincidentally - this thread has answered a question is was about to ask elsewhere.

Should I bother ticking the bother ticking the “raised centre pole pieces” box on the Fralin website when ordering new pickups for a mid-80s Japanese Squire J?

The answer smells like “yes”!

 

[walterw]

Thanx ww, Do you know if anyone has successfully adjusted the inner poles on an sjb1. I have already tried it on a few fender jazz pups and ruined them. rekon maybe i should have read more threads first and or tried heating them pup a little with a hair dryer. Not sure if that would have loosened the apparent vulcanizing.

i have, but it's sketchy.

duncan F-style pickup magnets tend to be really tight and hard to nudge, which seems to translate to a higher risk of killing the coil.

 

[walterw]

Should I bother ticking the “raised centre pole pieces” box on the Fralin website when ordering new pickups for a mid-80s Japanese Squire J?

The answer smells like “yes”!

it's an absolute yes IMO

 

[Nickthebass]

it's an absolute yes IMO

You can rest easy … the box has been ticked. Well … I’ve emailed the guy at Bass Direct so now it’s just a waiting game.

 

[dwizum]

There's no free lunch when trying to match the radius of the strings. If the pickup is built with taller poles in the middle, you're not only moving the magnetic field up closer to the higher-up strings, you're also adding a larger/stronger magnetic field and a larger chunk of permeable and conductive material right under those strings. You're going to get more difference output than the height change difference would suggest and also an ever so slightly warmer tone on those two strings. Using the same size magnets but pushing the center poles up is "safer" in that sense (you're not changing the characteristics as much because you're using the same magnets in all positions) but really depends on the structure of the coil, in terms of any potential impacts. If the magnets are already close to the bottom of the coil, the coil is already near the sharp corners of the field, and pushing the poles up can shift the field around the coil for those strings enough to change the tone.

In either case, a little goes a long way and you definitely don't want to actually follow the radius of the fretboard with the tops of the magnets, you're probably going to be happier with less radius than that.

This is where the P pickup is really genius since you can tilt each half separately and get the pickup to follow the curve of the strings without having to alter the characteristics of the pickup. Or just stick to basses with flatter radiuses. And stronger pickups, placed further away from the strings - which gives you the same overall output but with less string to string difference (since the relative differences from pickup to string are less when the pickup is further away).