Dead spot removal

johnk_10 · #1 02-22-2011, 12:17 AM

i was noticing that one of my jazzmaster basses (the featherweight, 7lb 9 oz shoreline gold one) had a slight dead spot on only one note. it was the very common 'D' on the G string (7th fret). the surrounding notes were ringing out and sustaining fine, but when i played the D, i could actually feel the neck shake/resonate and it slightly choked out. since the swamp ash body on this particular bass was so light, i made a point of selecting the lightest weight neck that i could find for it which weighed only 1lb 6 oz (most fender type necks are 1lb 8oz - 1lb 13oz).

way back in 1979, when i discussed this issue that's very common on Fender basses with Leo Fender, he pulled out a small C clamp, clamped it on the headstock and said, 'play it now'. sure enough, it was gone, and although it probably moved to a lower note, i sure as heck couldn't find it. this is also the same premise/solution that the 'fathead' (brass plate on the back of the headstock) and later 'fatfinger' (a small c clamp), both of which have been discontinued, were based on, which is adding mass to the headstock to change the neck's resonant frequency.

so, yesterday, i started experimenting with various sized (and weight) C clamps to see if i could solve the dead D problem on my bass. since the body is so lightweight, i wanted to make sure that i added only enough weight to solve the problem and not create any neck dive/balance issues. i'm using gotoh's res-o-lite reverse tuning heads on it, which made it balance perfectly. after a bit of experimentation, i found that the smallest 3 oz C clamp that i had, completely eliminated it. i figured that if i installed a standard weight set of heads (or just two of them) it would solve the problem, but i didn't want two of one type, and two of the other. i also didn't want to just replace the res-o-lites with a whole set of standard weight ones, since 6.5oz would surely create neck dive, plus the res-o-lites are so much smoother and have no slop in them whatsoever. so, i went to my local hobby shop and bought a pack of tungsten 3/8' cylinder weights that are used for pinewood derby cars.

tungsten is the new replacement for lead, since it's non toxic and actually weighs 1.7 times more than the same size piece of lead (which i learned 8 years ago when i was making and balancing my own r/c micro helicopter blades).

anywho, figuring that it was going to take at least 2 oz of weight to solve it, i removed two machine heads and bored two 3/8" holes under each of them to inlay the 1/2oz tungsten cylinders (see pic below with all four inlaid and an extra one laying on top to show it's size)).

i first tested it with only 1 oz added (under the A string key), and while it was a bit better, the dead spot was still noticeable. while testing, i left the holes slightly shallow so that the base plate of the tuning key would 'clamp it in place'. so i ended up using four cylinder weights (two under the D key and two under the A key). i tested it again and the dead spot was not only gone, but it didn't seem to affect any of the other notes, so i bored the holes so the weights would sit flush and epoxied them in. the 2oz of added weight has not upset the balance of the bass at all, it's still very lightweight at 7lbs 11oz, and all of the notes sustain and ring out beautifully (running a set of TI Jazz flats on it). i couldn't be happier with the bass now.

sorry for the long post, but i just thought that i'd post this as a possible (and an invisible) solution for those of you that may be experiencing a dead spot issue.

FrenchAK · #2 02-22-2011, 12:24 AM

Good stuff!

I recall reading a post only yesterday that said the only way to get rid of a dead spot was to buy a new neck.

Love the Jazzmaster basses, BTW.

johnk_10 · #3 02-22-2011, 12:27 AM

Quote:

Originally Posted by FrenchAK

Good stuff!

I recall reading a post only yesterday that said the only way to get rid of a dead spot was to buy a new neck.

Love the Jazzmaster basses, BTW.

thanks. well a new neck is certianly one solution, but it's still not a guarantee that the new one won't have them (and usually somewhere else). i just found this to be a better way of 'tuning it out'.

fretster · #4 02-22-2011, 12:39 AM

Nice work! Very clever hiding the weights under the tuners!

bassbenj · #5 02-22-2011, 12:44 AM

Quote:

Originally Posted by johnk_10

thanks. well a new neck is certianly one solution, but it's still not a guarantee that the new one won't have them (and usually somewhere else). i just found this to be a better way of 'tuning it out'.

EXCELLENT POST!

How did you drill "flat bottom" holes? I am probably wrong, but in the photo those weights appear longer than the thickness of the headstock. The holes don't go all the way through do they?

johnk_10 · #6 02-22-2011, 12:49 AM

Quote:

Originally Posted by bassbenj

EXCELLENT POST!

How did you drill "flat bottom" holes? I am probably wrong, but in the photo those weights appear longer than the thickness of the headstock. The holes don't go all the way through do they?

nope. they go within an 1/8" of the face of the headstock. i actually shortened the weights by about .045" to make sure that the wood wouldn't get too thin, so they're just under 1/2 oz each now.

to drill the holes, i used a forstner bit that has a very short indexing point. when i got the holes close to the correct depth, i used a dremel to flatten the bottom of the holes until the weights were flush.

thumpbass1 · #7 02-22-2011, 04:56 AM

Ingenious! Granted the idea of drilling and plugging the holes with metal weights won't appeal to everybody. I still think you came up with an original approach towards solving the age old problem of dead notes in some basses.

giacomini · #8 02-22-2011, 05:00 AM

Great!

I'm wondering how much weight will I need to get rid of my dead spot... It is already in a lower note (D string, 7th fret).

I'm going to try my c-clamps, but I'm aware that I'll need a bit more weight, since my tuners are the Fender-Schaller-deluxe-light ones...

PS. OK, I see. My light tuners might not have enough room to get the weights under...

JPrinos · #9 02-22-2011, 05:22 AM

Very elegant installation. Beats gluing a honking big nut on the back of the neck!!

KJung · #10 02-22-2011, 05:25 AM

Very cool! It has been long known that really the only 'possible' fix for a deadspot is to add weight to the headstock (the 'Fatfinger' is a product designed for this). That is a pretty cumbersome fix, and often doesn't work anyway. Your solution is very cool.

C.Linton · #11 02-22-2011, 05:29 AM

Nicely done. It would have been nice to have this solution when I owned that EB-3L. Do you think it might have worked for that? Or would it have further compromised the integrity of the already potentially fragile Gibson headstock?

steve_rolfeca · #12 02-22-2011, 05:37 AM

It's important that people try the c-clamp trick first, to see if it works on their particular bass. Not all dead spots are the same, or respond to the same amount of weight.

In giacomini's case, a dead spot way down on the d-string could be caused by other issues.

KJung · #13 02-22-2011, 05:43 AM

Quote:

Originally Posted by steve_rolfeca

It's important that people try the c-clamp trick first, to see if it works on their particular bass. Not all dead spots are the same, or respond to the same amount of weight.

In giacomini's case, a dead spot way down on the d-string could be caused by other issues.

+1 My guess is the 'adding weight to the headstock' to fix a serious dead spot has probably a 25% success rate.

bassclef112 · #14 02-22-2011, 06:32 AM

Excellent solution! I have been a proponent of Fatfingers for years - they enabled borderline instruments to become more than usable with the dead spot shift towards the nut. I still use them on several basses and am quite happy with the results.

I can only add that this kind of fix (or a Fatfinger for that matter) typically targets one piece necks with or without fingerboards and Fender style headstocks for the traditional dead spot locations (5th to 7th fret on the G string).

Multi-lam necks can respond differently so you may not get the same kind of results. The spot may not move towards the nut but surface in an even more inconvenient location. Then again, it might work in certain cases. I've had results go both ways.

+1 on steve_rolfeca's post - check it out first with a conventional method.

Square headstocks require some experimentation to find the best spot for the clamp, and be sure to check all the other notes for continued sustain.

JPrinos · #15 02-22-2011, 06:37 AM

Quote:

Originally Posted by KJung

+1 My guess is the 'adding weight to the headstock' to fix a serious dead spot has probably a 25% success rate.

It took a while to find out where exactly to put the weight to affect the deadspots. I'd venture that the success rate might be higher.

martyman5000 · #16 02-22-2011, 06:44 AM

Am I confusing balancing a bass with a dead spot? This does not make any sense to me at all.

KJung · #17 02-22-2011, 06:58 AM

Quote:

Originally Posted by martyman5000

Am I confusing balancing a bass with a dead spot? This does not make any sense to me at all.

Not a balancing issue. Assuming you know what a deadspot is, the only way to 'possibly' eliminate or reduce one is to change the 'mass' of a neck, and hence the necks 'resonant frequency' or whatever the correct term is. One way to change the mass of a neck is to add weight to the headstock. There are products, like the fatfinger, that are designed to do this. The OP just used a more 'elegant' method of doing this.

martyman5000 · #18 02-22-2011, 07:07 AM

Hmm interesting....I read this and it somewhat gave me an idea of what it means. I always assumed it was because the truss rod was too tight making the neck rigid and not providing vibration.

http://www.acoustics.org/press/137th/fleischer.html

johnk_10 · #19 02-22-2011, 09:47 AM

Quote:

Originally Posted by martyman5000

Hmm interesting....I read this and it somewhat gave me an idea of what it means. I always assumed it was because the truss rod was too tight making the neck rigid and not providing vibration.

http://www.acoustics.org/press/137th/fleischer.html

actually, if a neck didn't vibrate at all, or at least very little you probably wouldn't have a dead spot. it has to do with the resonant frequency of the neck. usually, you can actually feel the neck shake only on the note that is dead. and of course, you can't just add the weight anywhere (like under the heel). when testing it, i tried a clamp on the base of the neck and it did nothing to address the dead spot. truss rod adjustments can affect them though.

johnk_10 · #20 02-22-2011, 09:50 AM

Quote:

Originally Posted by steve_rolfeca

It's important that people try the c-clamp trick first, to see if it works on their particular bass. Not all dead spots are the same, or respond to the same amount of weight.

In giacomini's case, a dead spot way down on the d-string could be caused by other issues.

+1

also, it's not always necessary to add weight. you can also try removing weight, for example, if you bass has heavy tuning keys and installing light weight ones on it.