Article: Tips for Buying a Used Electric Bass
by Bruce Richardson
Looking for a good used bass? You should know some important
1) The neck is the single critical component. All others are easy and cheap (in comparison) to repair, including refinishing.
2) Any bass neck can be ruined within a year (even weeks) if the bass has not been maintained--no matter how expensive the instrument.
3) Conversely, even the cheapest bass can have a perfect neck, if the owner has maintained it.
4) Repairing a bowed or warped bolt-on neck is expensive to impossible. Replacing it is expensive, if possible at all (many bass manufacturers don't stock necks for long after a particular model is produced). You can rarely repair a badly warped neck-thru bass without completely rebuilding the instrument from scratch. Neck repair is rarely practical compared to the price of a good used, or even new instrument.
5) Action is not raised or lowered by adjusting the neck relief. Very important...more on this later.
WHAT TO LOOK FOR IN A BASS AD
Any bass player who knows what he's doing knows the neck is critical. An ad for a good bass will always state the neck condition, because this is the primary selling point. The seller will want to state it. The following words are usually used to describe well-maintained necks: Perfect, Straight, Low-Relief, Zero-Relief, Well-Maintained
If the neck condition is not described in a bass ad, it means one of two things: Either the seller does not know anything about basses, or the seller knows the neck is ruined, and hopes that you don't.
Either way, RED FLAG. It means you MUST VISUALLY CHECK THE NECK, or you may have expensive regrets. Even if the seller says the neck is perfect, CHECK IT.
In particular beware of any bass that "has sat unplayed for years" or any other description implying that this is a great bargain because of the lack of wear. Any bass that has sat unplayed for years has almost assuredly sat un-maintained for years, too. That means it's almost a 100% chance the neck is ruined.
RED FLAG #2: If someone tells you there's more relief in the neck because they like "higher action," INSPECT IT CLOSELY. This can mean only two things...that the seller either knows nothing about setting up an instrument or he's lying to you. Either way, you get screwed, so don't fall for it. Preference for higher action has nothing to do with neck warp. You raise action at the bridge, not by dialing excessive relief, i.e. warp, into the neck.
Sometimes people refer to adjusting the truss rod so that the action will go lower. That's legit. If the neck has gone out of adjustment, and there's too much relief, you can't lower the action without fret buzz. But, this refers to the "constant maintenance" aspect of bass ownership...not a bass that has been allowed to sit for weeks/month/years on end, out of adjustment. Once that has happened, it's not out of adjustment any more. It's permanently warped.
It's rare to find a bass that has too much "back-bow," that is, a hump in the middle. That's because the tension/force of the strings works against that condition. One thing that could cause a temporary back bow is the humidity going up. Example: An owner adjusted the truss-rod through the winter (while the heater is reducing humitidy), and didn't readjust it (loosen) in the spring/summer, when the humidity goes back up. Loosening the truss rod should fix this, but be aware that a permanently back-bowed neck is a serious defect, and it will be nearly impossible to avoid fret buzz without stupidly high action. You will very rarely encounter this, though. The forces of nature are pulling the opposite way.
HOW TO CHECK A BASS NECK
1) Hold down E (or B) string on first fret with your left hand.
2) Hold down same string on last fret with your right hand.
3) Hold the bass up, so you're looking at the "top" side of the neck, across the fretboard, level with your eyes, halfway between the two frets you're holding (approx 9th to 10th fret).
If there is more than a credit-card's gap between the string and the fret at this center point...you need to see the neck adjusted before you buy. A 1/2 turn of the truss rod nut should be more than enough to bring the neck into perfect flatness. Some people refer to this as "having some room in the neck," meaning that the truss rod is functioning in its role of balancing the tension of the strings without placing the neck under extreme pressure. If it takes more than 1/2 turn to get the neck in adjustment, or you feel lots of tension as you bring the neck into adjustment, the neck is probably ruined.
HOW NECKS WORK
Inside the neck, there is a metal rod called the "truss rod." Some basses (especially Rickenbackers) have two. The truss rod is there to balance against the natural pull of the strings, so that the neck doesn't get pulled forward into a bananna-shape.
On a perfectly maintained bass, the truss rod has been adjusted to hold the neck either perfectly straight, or with a slight "relief," somewhere between the thickness of a credit card (.030") and about half that (.015). Fretless basses should be dead flat to .015 (to get that signature "mwaaaah" sound).
Necks only warp when they're defective (not often) or poorly maintained (e.g., never adjusting the truss rod, therefore allowing the string tension to pull the neck into a permanent bow).
Remember this important rule: The Truss Rod is NOT THERE to correct a warped neck. It is there to prevent the neck from warping. If the neck has been allowed to bow/warp, it has not been maintained. Period.
WHAT IF A SELLER JUST CRANKS THE TRUSS ROD TO FOOL BUYERS??
First, it probably won't work. No amount of cranking on the truss rod will overcome a bass neck that has been allowed to warp permanently. It is only strong enough to counterbalance the string tension. Wood is VERY stubborn. The truss rod will likely break...usually, by "shearing off" right below the adjustment nut.
And..if a seller tries this, you can tell. The truss rod nut will be extremely hard to turn. It should turn easily, in both directions.
So, you should always check it, or ask the seller to show you that it moves freely. If a seller starts getting nervous or defensive, WALK AWAY.
Anyone who is selling a well-maintained bass will be PROUD to show you that the neck and truss rod are fully functional. Any bass more than a few weeks old that is showing excessive relief/bowing should be viewed with absolute suspicion. Central heating/airconditioning will suck the moisture out of the neck wood, and permanently ruin a neck in no time at all...literally curing it into a permanent bow/warp.