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sirmuppet

Setups on a 7.25 radius Jazz Bass - High volume on E & G

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So I've Googled this to death and it's driving me nuts. I have a 62 reissue Japan Jazz Bass with a vintage style bridge. It has a 7.25 radius and flat Jazz Bass pickups. So naturally the A & D are further away from the pickups than the E & G so the E & G produce more volume. Using Fenders guide I have it set with .35mm relief on the neck (cappo'd at the first fret and held down at the last with being measured under the 8th fret), 2.4mm height on the bass side at the 17th fret and 2 at the treble side. Having it arc the same as the fret board there's 2mm more distance between the A & D than the E & G. So no wonder it's louder. 

Like I said I've googled it and tried to find a way to fix this. The only one I can get to work is lowering the middle two strings as low as I can without any issues and then raising the outer two until the volume normalises. I did this by ear and when I found the volume was about right I measured it and there was only about 5mm of a difference in height between the inner and outer strings. 

So who of you have a 7.25 Jazz bass with flat pickups without this issue? What setup do you have Relief (cappo'd like above), string height at the 17th fret, pickup height (Held down at the last fret), anything else?

FYI my action is a tad over 4mm on both the E & G and around 2ish in the A & D when I get the volume balanced. I have tried other pickups (SJB3's which were too bright, Dimarzio Model J's were too tall and I'd need to shim the neck a lot), currently has Fender 74's in it. 

I'm looking for any help as I haven't found anything in my searches really. I love this bass and just hope there's a fix that's easy that I'm just not seeing.

Thanks for any help. 

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5 hours ago, whamni said:

A small washer the same size as the magnet pole placed on the D & A poles

Does this really work? I'm not dissing the idea, just interested in the physics. 

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6 hours ago, whamni said:

A small washer the same size as the magnet pole placed on the D & A poles

Interesting. Does the washer not need to be magnetised also? I think I have some Neo magnets around the same width as the poles, would these work?

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Some pickup manufactures made magnets with different height/cambered pole pieces to overcome it. DiMarzio have pups with adjustable height pole pieces and I think some of the later Fender ones have raised centre pole pieces, (maybe Lace as well).

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I get the benefit of raised pole pieces, just not sure that a plain washer will have the same effect. Surely any magnetic flux transmitted through the washer would be much weaker than the pole magnet itself? I've heard of small neo magnets being used to boost pickups (sometimes placed on the bottom of the pickup). Could also be placed on top of the pole but the neo mags might then overpower the G and E. They might also have noticeably different tonal characteristics to alnico.

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10 hours ago, mybass said:

Some pickup manufactures made magnets with different height/cambered pole pieces to overcome it. DiMarzio have pups with adjustable height pole pieces and I think some of the later Fender ones have raised centre pole pieces, (maybe Lace as well).

Yeah. I've tired the Dimarzios but with the magnet bar on the bottom they're too tall. Shim in the neck works but then the trench guide on the high mass saddle is pointless. Plus the Dimarzios didn't have that Jazz sound. I couldn't see any off the shelf Jazz pickups that Fender sell that had this though I do know they had them on the American Jazzes at some point. They did have a pickup with adjustable poles but the only time I've seen it is in the bridge position of the American Jaguar.

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2 hours ago, ikay said:

I get the benefit of raised pole pieces, just not sure that a plain washer will have the same effect. Surely any magnetic flux transmitted through the washer would be much weaker than the pole magnet itself? I've heard of small neo magnets being used to boost pickups (sometimes placed on the bottom of the pickup). Could also be placed on top of the pole but the neo mags might then overpower the G and E. They might also have noticeably different tonal characteristics to alnico.

This was what I was thinking. I have these magnets and could try. The washer I'd be concerned about as it's not magnetic and I'd want to know if that would be an issue. As for the Neo's, I could easily try that but I never thought about it changing the sound being a different type of magnet. I'll give it a try at next rehearsal and let you know (Bass amp is in for repair). 

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Email Fender and ask if the pole pieces can be raised by pushing them up from underneath. I did this with Nordstrands on my Sire after emailing them, they said it would be ok but not to lower them again afterwards, I just applied a bit of pressure rather than tapping with a plastic hammer like they recommended though. Some pickups don't have any leeway for this though ie the pole pieces are flush with the pickup on both sides.

 

Failing that you can buy pickups with a matching radius, Nordstrand will do them for you - EDIT - looks like they're £155 a set at Bass Direct, not sure if they're 60s or 70s winding though.

Edited by lemmywinks

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This volume difference - it's seriously noticeable is it? How are you measuring it? Is your amp EQ flat?   I have a number of Jazzes and using Fender's specs I've never had an issue. You've set, relief, action and intonation first, then pickup height last, all according to Fender specs?  The usual way to compensate for volume issues is to adjust pickup height.   The specs are merely a starting point from which to work from. Adjust to suit.

I've never heard of using additional magnets  - sounds a bit of a crazy idea to me.  The first thing I would do after flattening my EQ and setting to Fender specs is to use a new/different set of strings.  

 

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3 hours ago, sirmuppet said:

Yeah. I've tired the Dimarzios but with the magnet bar on the bottom they're too tall. Shim in the neck works but then the trench guide on the high mass saddle is pointless. Plus the Dimarzios didn't have that Jazz sound. I couldn't see any off the shelf Jazz pickups that Fender sell that had this though I do know they had them on the American Jazzes at some point. They did have a pickup with adjustable poles but the only time I've seen it is in the bridge position of the American Jaguar.

Delano (Germany) might make you a set with radius magnets.

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7 hours ago, Muppet said:

This volume difference - it's seriously noticeable is it? How are you measuring it? Is your amp EQ flat?   I have a number of Jazzes and using Fender's specs I've never had an issue. You've set, relief, action and intonation first, then pickup height last, all according to Fender specs?  The usual way to compensate for volume issues is to adjust pickup height.   The specs are merely a starting point from which to work from. Adjust to suit.

I've never heard of using additional magnets  - sounds a bit of a crazy idea to me.  The first thing I would do after flattening my EQ and setting to Fender specs is to use a new/different set of strings.  

 

Yeah. It's really noticeable. Have tried new strings (these ones have been on just about a week now). Followed the Fender setup guide to the T in order. The EQ on my amp is normally flat. In fact the one at rehearsal as an EQ you can bypass which I normally do. I would normally agree about pickup height but how do you compensate when it's the two outer strings that are the loudest? I've even tried putting the pickup way down and raising it bit by bit, just in case there is a sweet spot there somewhere. Are your Jazzes vintage radius or modern?

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I should add I've tried a Fender Hi mass bridge, Hipshot Kickass and it currently has a USA vintage reissue one on. I've ordered some Rotosounds just in case it's the brand of string but I doubt it, Ernie Balls are fine on all my other basses. Another trick I tried was to get my effects pedal out and set it to the bypass tuner setting when setting my bass up, just so I could check the volume differences. 

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Uneven string balance is a pretty common feature of small radius necks with flat pickups. Winding the pickups down a bit can sometimes help to even things up a little. Otherwise just adjust your playing touch and dig in a little more with the D and A (or ease off on the G and E). It's pretty easy to get used to. I've got a couple of vintage Fenders and have become quite fond of their little idiosyncracies!

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Both my current ones are vintage and I don't have any noticeable volume differences. Mine are set up to Fender specs more or less.  I can only suggest reducing the height of the pickups or swapping them out completely.  Very odd.

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Magnetic field intensity is inversely proportional to the square of distance from the source (ie. it decreases exponentially ). The D and A strings  are around 2mm further from the poles on a 7.25" radius neck and that's enough to make a measurable difference in the output of those strings. There are other factors involved though, such as the strength of the magnets, the distance they are from the strings (the greater the distance, the less pronounced the differential effect), the gauge of the strings etc. How much of an issue it is will vary from bass to bass. On some it's hardly noticeable, on others more so. I can detect it on my '72, but it's easy enough to play round once you know it's there.

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9 minutes ago, ikay said:

Magnetic field intensity is inversely proportional to the square of distance from the source (ie. it decreases exponentially ). The D and A strings  are around 2mm further from the poles on a 7.25" radius neck and that's enough to make a measurable difference in the output of those strings. There are other factors involved though, such as the strength of the magnets, the distance they are from the strings (the greater the distance, the less pronounced the differential effect), the gauge of the strings etc. How much of an issue it is will vary from bass to bass. On some it's hardly noticeable, on others more so. I can detect it on my '72, but it's easy enough to play round once you know it's there.

This ^^^

I've got it kinda setup so it's less noticeable. Is 3.5mm at the 17th on the E with 2.3mm on the A & D high or is it acceptable? I mean I can play it and I don't have an issue but just curious if this is in the realms of normality. Pickup dips a little towards the E.

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Everyone's 'normal' is different when it comes to setup lol! Here are the measurements for my '72 and a few pics by way of comparison.

    Action at 17th fret: G - 2.2 mm, D - 2.0 mm, A - 2.0 mm, E - 2.6mm (I measure using a 64th inch ruler, these are mm conversions)

Distance of strings from pickup poles (with strings depressed at last fret:

    Neck pickup: G - 3.0mm, D - 4.8mm, A - 4.8mm, E - 3.6mm

    Bridge pickup: G - 3.2mm, D - 4.8mm, A - 4.8mm, E - 3.6mm

Pickups are an old set of Fender Custom Shop 60's 

IMG_20190820_152738_resized_20190820_033634921.thumb.jpg.0f3dee05d0055795a99c8080d5346b4d.jpg

IMG_20190820_152727_resized_20190820_033634589.thumb.jpg.60003bc12acfb5cacedd6cb026d156e0.jpg

IMG_20190820_152713_resized_20190820_033634256.thumb.jpg.31ee8c3252efa60463cc39203cc40ae0.jpg

Edited by ikay

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3 hours ago, ikay said:

Everyone's 'normal' is different when it comes to setup lol! Here are the measurements for my '72 and a few pics by way of comparison.

    Action at 17th fret: G - 2.2 mm, D - 2.0 mm, A - 2.0 mm, E - 2.6mm (I measure using a 64th inch ruler, these are mm conversions)

Distance of strings from pickup poles (with strings depressed at last fret:

    Neck pickup: G - 3.0mm, D - 4.8mm, A - 4.8mm, E - 3.6mm

    Bridge pickup: G - 3.2mm, D - 4.8mm, A - 4.8mm, E - 3.6mm

Pickups are an old set of Fender Custom Shop 60's 

IMG_20190820_152738_resized_20190820_033634921.thumb.jpg.0f3dee05d0055795a99c8080d5346b4d.jpg

IMG_20190820_152727_resized_20190820_033634589.thumb.jpg.60003bc12acfb5cacedd6cb026d156e0.jpg

IMG_20190820_152713_resized_20190820_033634256.thumb.jpg.31ee8c3252efa60463cc39203cc40ae0.jpg

This is awesome. Thanks

Mine measures as follows: E: 3mm, A: 2.25mm, D: 2mm, G:2mm

Neck pickup: E: 3mm, A: 4.8mm, 😧 5mm, G - 3mm 

Bridge pickup: E: 2.25mm, A: 3.25mm, 😧 2.75mm, G - 1.75mm 

My bridge pickup has a weaker output the the neck so it's closer.

Pics attached

 

IMG_1766.jpg

IMG_1767.jpg

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