77 P-Bass Weak Note Issue

[big_teee]

A customer called me this A.M. with a 77 P-Bass that has one note on the G-String that is weak.
The Local Vintage Guitar Shop changed the string and checked the Frets and all looks fine.
One note on the string is weak, and He called to get me to ReWind the Pickups. WTF?
I don't know if that will fix anything or not.
Maybe just a weak Magnet?
Any Thoughts, or am I getting in to No-Mans Land?
B_T

[loudthud]

This is a problem you will find on most Fender type basses. I call it the dead spot, usually around the 5th fret on the G string. The problem is that the fundamental tone of the note dies rather quickly leaving the 2nd harmonic. You can see it on an oscilloscope or hear it when the amp has a huge midrange dip around 800 Hz.

I read one thing that suggests that this is the reason Leo changed the headstock design of the original Precision bass. The mass of the headstock seems to have something to do with it. Adding one of those metal plates to the headstock moves it around a little bit but IMHO they do not cure it. I spent a lot of money trying to find a bass with a 34 inch scale that didn't do it and there are very few. A Kawaii bass with neck thru construction I found is fairly imune but depending on the truss rod adjustment it comes and goes. Graphite necks are the best cure but you lose that woddy resonance I like so much in a Fender bass. Most 30 inch scale basses do not do it.

[big_teee]

This is a problem you will find on most Fender type basses. I call it the dead spot, usually around the 5th fret on the G string. The problem is that the fundamental tone of the note dies rather quickly leaving the 2nd harmonic. You can see it on an oscilloscope or hear it when the amp has a huge midrange dip around 800 Hz.

I read one thing that suggests that this is the reason Leo changed the headstock design of the original Precision bass. The mass of the headstock seems to have something to do with it. Adding one of those metal plates to the headstock moves it around a little bit but IMHO they do not cure it. I spent a lot of money trying to find a bass with a 34 inch scale that didn't do it and there are very few. A Kawaii bass with neck thru construction I found is fairly imune but depending on the truss rod adjustment it comes and goes. Graphite necks are the best cure but you lose that woddy resonance I like so much in a Fender bass. Most 30 inch scale basses do not do it.

So if the magnets are recharged would that cure it.
Did you ever go so far as to rewinding the pickups. Will that have any effect.
Thanks, for your Valuable Input. Seriously!
B_T

[loudthud]

Here is a picture of an experiment I did on a Hondo-II bass a got off ebay. The idea was that the position of the high string section effected the tone at the dead spot. I had a mis-matched P-Bass pickup set, the magnets repelled face to face, and found a mating orphan pickup that was the correct polarity. I Installed a switch to select the high string pickup. It didn't change the dead spot.

[big_teee]

Loudthud:
After reading your first Post, I called the guy back and talked him out of a rewind.
I read him your post and it was exactly his problem.
He Claims that this issue just started a while back.
The Shop Owner said it sounded ok to him and he has been trying to buy the 77 Bass.
I told the guy that rewinding would actually make the bass worth less, not more, on the Vintage Market.
I like your AC-DC Bass Experiment.
So If I read that correct, one pickup was RWRP and the Other Was not and you could switch them in and out with NoChg.
That looks like exactly like something I would do!
Your Control Plate, looks like some Alum. Pan like we used in the Phone Offices.
Later,
Terry

[David Schwab]

Yeah, the problem is with the neck, and not the pickup. Adding mass to the headstock might help, or even using a different bridge.

I wonder if the guy had switched the machine heads when the problem started. Some people try and use ultralite tuners and find it exasperates the problem.

[loudthud]

The two pickups on the D and G strings are the same polarity so no matter which one is selected, they always buck hum with the E-A pickup. The pickguard was just something I cut out of a scrap of aluminum because I didn't want to cut a hole in the plastic one that came with the bass even though it was in pretty bad shape. Just traced the plastic one, cut it out and drilled the holes.

I have many basses. Several G & L's, several P-Basses of various origins, lots of other one-ofs. Haven't owned a Jazz bass since the 70's. I thought a Ric bass might not have the dead spot because it had two truss rods. To my suprise it has two dead spots. One on the G string around the 5th fret and one on the D string around the 10th fret (same note!).

I got into this whole thing because I was trying to make a bass amp that sounded the way I wanted it to sound. Sort of an old time string bass flatwound tone. Trouble was that the deep midrange trench I liked in the amp emphasized the dead spot. So now I'm playing a Hofner knock-off (Rogue or Epiphone) with a 30 inch scale. I can even use round wound strings.

[big_teee]

Yeah, the problem is with the neck, and not the pickup. Adding mass to the headstock might help, or even using a different bridge.

I wonder if the guy had switched the machine heads when the problem started. Some people try and use ultralite tuners and find it exasperates the problem.

He's an older guy, I don't think he changed anything.
I told him If it were mine I would keep it stock, and put it back in the case, and play something else, anything he changes will make it less valuable.
Is this issue only with P Basses, or do the J Basses have the same problem?
T

[jrfrond]

I'm willing to bet money that the "weak note" is either C, C# or D (5th, 6th, 7th frets respectively), because probably close to 90% or so of Fender and clone basses have a dead spot there, some worse than others.

I've found that the dead spot is caused by the interaction of three factors: neck mass, neck modulus, or stiffness and body/neck coupling/interaction.

There's not much you can do about neck mass. It is what it is, unless you want to play with a small C-clamp on your headstock. Ironically, in an era when many players go to lightweight tuners, the normally heavy Fender/Schaller machines actually save the day a bit because of their added mass. There IS a more elegant solution called the Fat Finger Sustain Enhancer. Essentially, it's a nicer-looking C-clamp. Ironically, though it sports the Groove Tubes name, it's made by Fender (Fender owns GT).

Then there is neck stiffness. A lot has been done to stiffen neck construction. Multi-lam layups, graphite bars, thicker fingerboards, and or separate fingerboard/neck construction.

Then lastly, there's the body/neck joint coupling, and body/neck wood difference. Neck-throughs have no issues with this, because the platform is one contiguous piece, with no decoupling caused by a bolt-on neck joint to a body made of a different wood. The "body" is just glued-on and shaped wings, as cited above with the Kawai, but also Alembic, Rickenbacker, Ibanez and a whole host of other neck-through basses. Set-neck is almost as good, but if the neck is heavy and the body is really light, there may be issues.

The best case scenario for a bolt-on bass is one where the body and neck woods are of similar densities, and the neck has some sort of laminate construction.

OK, what about this '77 Jazz Bass? Jazz basses are cursed a bit. I love them, but many of them, mostly the 1pc. maple neck versions, suffer from "rubberneck" syndrome, and are kind of flexy below the 5th fret due to their thin construction, and this is a sustain killer that, in principle, is no different than the effect a tremolo has on a guitar. Rosewood FB versions are a bit stiffer due to the fingerboard glue joint. One workaround for this is to keep the truss rod as tight as possible (meaning zero neck relief), because it will add a small measure of stiffness to the neck. It will also necessitate increased string height for most players, but with zero relief, it will automatically play easier, even with the extra height.

For the record, Fender's American series J-Bass has a separate maple neck/fingerboard, plus graphite bars in the neck, and the problem is greatly reduced. Unfortunately, there's not much you can do to a stock neck.

[David Schwab]

He's an older guy, I don't think he changed anything.
I told him If it were mine I would keep it stock, and put it back in the case, and play something else, anything he changes will make it less valuable.
Is this issue only with P Basses, or do the J Basses have the same problem?
T

You can get one of those weights that clamp onto the headstock. That will probably fix it, and it not a permanent mod.

[big_teee]

You can get one of those weights that clamp onto the headstock. That will probably fix it, and it not a permanent mod.

I called him back and told him it is a neck issue.
He told me he took it in for a complete refret Job.
Probably a waste of money!
I told him I would be taking his money if I rewound the Pickups.
I guess the Re-Fret Guy didn't tell him that.
B_T

[loudthud]

I read somewhere that the early Motown bass players would press the headstock against a wall while they were playing to cure the problem.

[jrfrond]

I read somewhere that the early Motown bass players would press the headstock against a wall while they were playing to cure the problem.

Now THAT'S a real pain-in-the-ass!

[Ronsonic]

One workaround for this is to keep the truss rod as tight as possible (meaning zero neck relief), because it will add a small measure of stiffness to the neck.

I've spent little time setting up basses and am not expert, but what I've noticed with guitars is that there is a range, a small range but there, where the truss rod is tight enough to get the relief you want, but if you tighten it just a little more the relief isn't changed, but the feel and resonance of the neck tightens up and "snaps into focus." It isn't a big thing but is noticeable on a guitar. With the much heavier bass string (relative to neck mass and stiffness) I would expect it to make a bigger difference.

[David Schwab]

I've spent little time setting up basses and am not expert, but what I've noticed with guitars is that there is a range, a small range but there, where the truss rod is tight enough to get the relief you want, but if you tighten it just a little more the relief isn't changed, but the feel and resonance of the neck tightens up and "snaps into focus." It isn't a big thing but is noticeable on a guitar. With the much heavier bass string (relative to neck mass and stiffness) I would expect it to make a bigger difference.

Also because a bass neck is much longer, so it tends to be more flexible.