Help adjusting truss rod on Ibanez SR506 6 String Bass

[daws0n]

Picked up a nice 2014 SR506 bass recently. It plays well with decent strings / notation and very low action. The neck profile and string spacing is not unlike a classical 6 string guitar, certainly won't surplus a 4 string for me but quite liking it so far! I have noticed that there is quite a bit of fret buzz on the lower frets, not noticeable when playing through an amp but more so without one.

 

I've measure the relief by capo'ing at the 1st fret and fingering where the neck meets the body - using a 0.40mm feeler guage I am able to move the string above the 8th fret. This suggests that there is not enough relief in the neck and I need to loosen the truss rod. This guitar however has 2 truss rods under the cover! I have not seen this before so looking for advice re: do's and don'ts for adjusting... With a single rod I'd turn 1/8th anticlock wise to loosen and leave it overnight or so. Should I do the same with this x2 or is there more to it?

 

Cheers all

 

Dawson

Edited August 17, 2023 by daws0n

[tauzero]

Are you sure you haven't got too much relief rather than not enough? I'd expect less than .4 mm between string and fret at the 8th fret.

 

I think you've got the right approach with the adjustment, although I'd say that as a further check you should see what the relief is on both the B and the C strings, and if it's different, adjust one of the truss rods accordingly - so if there's more relief on the C string than the B string, either tighten the truss rod on the C side or loosen the one on the B side.

 

Note: I've only adjusted a dual truss rod bass once - it did all work out fine, but I'm not an absolute authority on it.

Edited August 17, 2023 by tauzero

[daws0n]

0.4mm / 0.15 inch is what I usually aim for on my budget basses, I can't get them to play well with a dead straight neck. Aiming for 0.3mm was more trouble that is was worth last time. I've learn to live with a slight bow and highish action but this SR506 is a cut above build wise. I'll check with some smaller guages later to see what fits.

 

Good point re: measuring relief on both sides of the neck!

[NancyJohnson]

Dual truss-rods aren't particularly unusual - certainly I'd expect a wider necked instrument (ie a 6-string+ bass) to have two as a necessity.  Rickenbacker basses have them (which I've always thought was overkill).  The honourable member for Tamworth has answered how they're used quite succinctly.

 

Tweaking the truss rod(s) is easy enough and if done with a bit of patience and care, it shouldn't be an issue.  Just do little 1/8 or 1/4 turns tops and remember the rule or righty-tighy and lefty-loosey.  Results are generally instantaneous and in all honesty there's no real need to leave the neck overnight; detune the bass, adjust, tune up, repeat.  The woods/glues/construction of modern basses will allow for tweakage.

 

Remember also that the truss rods are only one element in the chain to achieve buzz free playing - doesn't matter how straight your neck is if you have a high fret.

 

 

 

 

[daws0n]

Through word of mouth it turns out that we live not far from a luthier! Top gent, neck and action carefully adjusted and guitar back in hand buzz-free on same day for a very reasonable price. Guitar needed a very minor 1/6th adjustment to the truss rods (loosen) and the action raising a touch aswell, it plays much better now.

 

A whole hearted recommendation for Mike Tarr

 

https://www.youtube.com/@mitarrguitars

Edited August 21, 2023 by daws0n