action changing later after truss adjustment?

tranceFusion · #1 07-07-2008, 10:37 AM

i bought a new bass over the weekend at guitar center. When I was there though, the action was quite low and the strings were doing a good bit of rattling. I asked them to raise the action a bit which they did (adjusted the bridge and the truss rod), and i bought the instrument.

A couple days later though, it seems like the action is jacked way up.. did the truss rod slip or something? is this normal? or is there a problem with the instrument? (or am i just going crazy?)

themarshall · #2 07-07-2008, 10:44 AM

That can happen if the trussrod is moved too much at once - common mistake in quest for instant results. IME 1/8 to 1/4 turn at a time with a day between works best. Also - may have been a big change between temp/humidity at store and where bass resides now. I'd suspect a combination of these factors before thinking the worst.

Stumbo · #3 07-07-2008, 10:45 AM

It takes awhile for truss rod adjustments to fully set.
It sounds like the truss rod was adjusted too much.

As you found out, it takes a couple of days for the neck to fully respond to truss rod adjustments. A truss rod adjustment should only be done with a 1/4 turn or less. Then you wait a couple of days to see how the neck responds and go from there.

I suggest finding a real guitar tech in your area and have the bass setup again.

Mike Shevlin · #4 07-07-2008, 10:48 AM

+1 some instruments need more attention than others. I adjust my Lakland 55-94 (minor changes) about once a month. If it continues to go from perfect to WAY OFF, it may be a problem with the instrument - every piece of wood is different.

tranceFusion · #5 07-07-2008, 10:54 AM

i have a good tech nearby, but am i crazy to think about doing this myself? i would like to learn simply so that i don't have to pay for a setup every time i change string gauges, buy a new instrument, etc..

BassLand · #6 07-07-2008, 11:02 AM

They over adjusted (loosened) your truss rod and the neck is now up. I would never go more than 1/2 turn in either direction then I would re-tune the bass and check it in 1/2 hour. I would even flex the neck gently until the TR/Neck settled. If you don't know how to achieve this I would go to a different place than where I bought the bass and explain to the repairman there what was done at the store where I bought it.

I see Stumbo said pretty much the same thing above. I did not see it initially...

powerbass · #7 07-07-2008, 11:13 AM

string height/action is dependent on curvature of the neck and saddle height. the neck curve is adjusted w/the truss rod and the saddle height is adjusted at the bridge. the depth of the nut string slots also are a factor. if you look down the neck from the bridge to the nut there should be a very slight concave curve - too flat or reversed curve/convex the strings will buzz since they would hit multiple frets at a time. to make a flatter curve i first loosen the strings then turn the truss rod - resight down the neck to see if the curve changed, if ok retune. then adjust the string height from the bridge measuring the height of the string from the bottom of the string to the fret/fret board. you can play w/these two things until you get the desired string height and neck relief. try Stewmac for set up books/videos

staindbass · #8 07-07-2008, 11:17 AM

any good guitar adjuster should know it takes 3-4 days for the neck to settle after adjustment . next time a guy adjusts yer guitar, ask him where the truss rod ends, if he dont know exactly, he shouldent adjust yer guitar. i love busting professional paid techs on that one. (the answer is one fret after there the neck joins the body looking from the back.) some custom instruments may differ. ive been a guitar tech since 1979 when i bought my first used bass with 1/2 inch high action and a book on fixing guitars. there is a fine art to those simple adjustments that is hard to learn. get some allen wrenches, and lower the strings. turn the allen wrench one complete turn on each one carefully. that way, you bring the action down on all the strings the same level. too muck? back up a 1/2 turn. not enough? go 2 turns. unless you are going in the studio soon, intonation is not as important as a comfortable guitar. you can learn truss rod and intonation later. good luck with it, any problems, pm me. johnny a

pbagley · #9 07-07-2008, 11:25 AM

Ask where the truss rod ends. Good one.

Once uppon a time there was a local manufacturer that made a 24 fret neck through "deluxe" bass but used the 21 fret truss rod. Adjustment at the body end. Can you guess what happened with medium strings?

Back on topic - I had an '80s Kramer for a while that had a neck like an S curve. I adjusted that thing once a day for about 2 weeks before it was (mostly) playable. 1/8 turn was the difference between OK and rattles at frets 2-4 and 11-14 with a medium action at the bridge.

The point - some pieces of wood are tough to adjust. Some old used bases have been abused by past owners. Good luck!

- Paul

69nites · #10 07-07-2008, 11:27 AM

there's plenty of information on talkbass about how to properly setup a bass.

a lot of people are scared of making truss rod adjustments but there's not much to them they're very easy just like any other adjustment.

if you are so inclined it's very easy to do yourself. If not it's also very easy to take it in and establish a relationship with a quality tech that will make your bass fit you like a glove.

tranceFusion · #11 07-07-2008, 12:05 PM

i don't mind learning new things, and i feel like once i know, i will put more effort into gett it right than somebody else.. not to mention that if i change my mind about action height or something i would be able to change it myself.

That said, I don't want to spend weeks wrecking the hell out of it, and then have to take it to a tech anyway