View Full Version : Gibson: truss rod v. no truss rod

Aug-30-2006, 4:36pm
Hi all,
As a total newcomer to the vintage market I was wondering what others' thoughts are on truss rods (or lack thereof) in vintage Gibsons. How have the non-truss rod necks generally held up without them?

Loar-mystique aside (if that's possible), is it better to have a vintage Gibson with the possibility of easier future adjustment, or will a good, well set-up pre-truss rod Gibson neck last me?

And what about the non-adjustible truss rods in the Loar and later A-0s?

Aug-30-2006, 6:49pm
A-0 w/o and A4 with TR, that I have, are both 1921 vintage, and are both are just fine.
I Have owned the Brown A-0 for about 19 years.

Bob A
Aug-30-2006, 7:42pm
I have a 1921 F4 without trussrod. There's never been a problem with the neck, and I don't expect there ever will be. My personal preference, doubtless formed by long exposure to this mandolin, is for the wider, thicker neck. I've in fact never heard of anyone ever having a problem with the pre-rod Gibsons.

I believe the trussrod was installed to provide strngth for a thinner neck, possibly made from cheaper materials. There are those who claim the acoustics are better with the trussrod; there are those who believe the opposite. I would consider the whole thing to be a non-issue, and suggest that you go with the neck profile you find most comfortable. Certainly lack of a trussrod is not going to affect the longevity or utility of the instrument.

Big Joe
Aug-30-2006, 11:39pm
The truss rod had several advantages. First, the neck did not have to be so large. Second, it allowed for MUCH easier set ups and neck adjustments. Especially with varying humidity and temperature levels across the country. If you had a problem with a neck with no truss rod, and it did happen, the fix was far more complicated than with a truss rod. The easier playing neck made it possible for more people to play with greater comfort and allowed for longer necks with fewer problems. The Truss rod was invented by Gibson in 1921 and was used on all instruments, not just the mandolin. Most companies have since switched to the truss rod. I have a 1920 F4, and of course, it does not have a truss rod. I like the playability and tone but I have very large hands. It makes playing my F5 much easier after playing the F4. The larger mass in the neck does give a different tone. More bottom end and more sustain and less chop as we are used to in today in modern music.

Aug-31-2006, 4:23am
Good summary there from Joe on the sound differences. I think the truss rod is mostly a tonal difference on the As and F2/F4, wheras on the F5 with the maple neck it is a set-up device too. a Maple neck will flex more than that super-stiff mahogany on the oval hole ones. I've had a couple truss rod As but never even took the cover off them, no need to adjust the rod IMO.

An interesting instrument comparison is a 1923 a snakehead vs a 1923 snakehead ajr. The Ajr has no truss rod, and jrs are indeed known for their increased bass response. Snakeheads have a slightly "Crisper" tone vs a non-truss rod A, which makes them sound a nice half-way between an oval hole and an F5 to my ear.

Aug-31-2006, 8:43am
Does the Snakehead have a crisper tone because it has a truss rod, or because the neck is thinner, or a different wood?

In a related/personal question, would the addition of a carbon fiber rod to a 1916 Gibson A1 change the tone?

Big Joe
Aug-31-2006, 8:46am
A good part of the tone difference in because of the increased wood in the non truss rod instruments. If you put in a truss rod, you will usually use a different wood (mahogany for example) rather than maple. This alone gives a more mellow tone. Add to that the increased mass of the wood. When you use a truss rod you generally use a thinner neck with longer scale and route out the area for the truss rod. The area is filled with an adhesive and the fingerboard attached. That gives a lot less wood for tonal creation than a non truss rod neck. Often the non truss rod has a shorter scale also. This gives a bit of difference in tone because of where the bridge sits and the tension on the strings. When you decrease the string length it alters the tension and alters the tone. With all these things combined, they are not going to sound alike. Here is the list:
Shorter string length
more wood in neck
lower tension on strings
bridge sits back farther
different wood in neck
no metal in neck
different sound hole shape and size

Any one of these would give a different tone, but when you combine all of them it is easy to see the tonal change in an F4 compared ot an F5 or whichever one you wish to compare.

Paul Hostetter
Sep-04-2006, 12:45am
Lower tension on the strings? Come on, now. On Gibsons, given the same string gauges tuned GDAE, the tension is always the same, whether it's a 2006 F-5, a 1930 F-4, or a 1910 A-Jr. The scale never changed from 13-7/8".

To the initial question, most "vintage" Gibsons (lower models than F-5) have a short, stout neck that really doesn't need an adjustable trussrod at all.

Sep-04-2006, 3:56am
Well, I have owned (and played) a 1915 A4 for 35 years. When I got it, it had a very badly bowed neck such that intonation and action were poor. I had the frets removed, fingerboard planed flat and refretted back in 1972. the board is thus thinner at the nut and at the soundhole ends than in the middle, and the binding is the same. This mandolin has been stable since '72 and the neck hasn't bowed again since then. There must be plenty of residual strength in that neck design......I use medium light strings....John

Sep-08-2006, 12:32pm
I also have a 1915 A4 like sprucetop1, except that I acquired it recently, and I had the same repair done. The fingerboard needed to be sanded or planed flat to correct a slight bow in the neck and improve the action and playability.

Paul Hostetter
Sep-08-2006, 1:33pm
I deal with old A models all the time and a slight bit of bow is routine. A little bit of bow after 75 years is forgiveable. The new frets make it a dream to play, and you know it's good for another few generations. Those mandolins are a marvel of good engineering.

Sep-08-2006, 2:14pm
Would you advise leveling the fretboard on an old Gibson that had a pretty fair bow that played and sounded real good, but with a little higher action than average?

Paul Hostetter
Sep-08-2006, 3:22pm
It would make it a lot easier to play. I assume that's what you want? I can't overstate how important the new (taller) frets are toward that end as well.

Sep-08-2006, 4:41pm
Paul's right, once the fret board is straightened the mandolin is easy to play. It's like I could tell before the repair that it had a nice sound but it was hard to get it to come out. After the repair the beautiful old tone just seems to come from it effortlessly. It makes a huge difference in how the mandolin feels and plays, which in turn affects the sound that you get from it.

Andy Morton
Sep-09-2006, 7:15am
Great thread---I have a 21 A-2--love the tone and sustain. I am using GHS 250 strings. I have considered going heavier, but I do not want to risk any issues with the top sinking or anything else.

What are some of the other string sets that people are using that are regarded as "safe" for pre-truss rod Gibsons??

Andy Morton
Madison, WI

Paul Hostetter
Sep-09-2006, 11:15am
Except for the occasional damaged one, I don't vary much from J-74s, which are a bit heavier than the GHS 250s. A few players like monels, but J-74s are essentially what Gibson was using in the teens and what is specifically formulated for that scale and that engineering to this day. D'Addario finally came out with J-73, a notch lighter gauge phosphor bronze string set. If you have an A or F that's held up for 50-80 years, there's not much you can do with J-74s to mess it up at this late date.


The GHS 250 set, which comes in several different materials, runs 10 15 24W 36W, the J-73 come in 10, 14, 24, and 38.

Sep-09-2006, 12:03pm
Paul- curious to know how you got your data about what gibson was using.. I have a few original string packets, but they are quite odd. they are unwound copper! I haven't micrometer'd them yet, but I also ony have A&E sets. I've been meaning to link up with a friend in the states who has several G/D pairs and string up a loar with them.. but I still have no idea what original gauges were!

Paul Hostetter
Sep-09-2006, 1:32pm
Old instruments with obviously original strings. I just miked 'em. And in a couple of instances, such as a couple of guitars, an F-4 and an Alright Style D, I wished I hadn't changed the strings. They sounded fine with the originals, and the new strings were no significant improvement. Of course they really hadn't ever been played.

No idea what your unwound copper strings would be. These were pretty normal wound and unwound strings of the proper types, with really different loop knots. Copper tends to effloresce to the surface of alloys, but light polishing takes that film of pure copper off and shows the real alloy beneath.

D'Addario claims it invented hex core strings, but I have a Martin string catalog from the 20s in which they talk about their hex-core bronze strings, including a choice of wound or unwound B strings. Gibson offered wound B's on guitars as well.

Sep-09-2006, 2:36pm
Did you micrometer them?

I've got some string packets that are unused that are the same ones listed in the service manual.. but I need the G&Ds yet to be sure http://www.mandolincafe.net/iB_html/non-cgi/emoticons/smile.gif

Alex Orr
Nov-24-2012, 12:05am
Just found this thread. I've got a Brentrup F5 that Hans made in '99 (technically, it is a 23M); it was his third mandolin, judging by the label. Thicker neck, no truss rod. I'm the fourth owner and in the two years since I've had it, I've had it looked at twice by luthiers for small issues (once because I screwed up the intonation when I knocked the bridge off during a string change cleaning) and both times I asked for their opinion on the neck. Both said they were surprised a recent high-end builder would make a mando without a truss rod, but also said the neck appeared to be fine, so I suppose there are instances today when an instrument can survive without a truss rod. Here's hoping it stays stable.

Also interesting to read Big Joe's comments on likely tonal effects of a non-truss rod mando. The sound on my Brentrup is everything he cited. The sustain is massive, and the mid- and low-range is very powerful. It still has a very loud chop, but it's not as much a cutting sounding chop as it is a loud and full chop. The neck is larger than most I've played, but as someone with hands that can easily palm a basketball and who came to mandolin from guitar, a larger neck is not an issue at all.

Nov-24-2012, 2:57am
2 1922 A's one, an A4 has a truss rod, expect they added it mid year,
and from top line down, (nickel plated TRC announces the new feature.)

as the prior plain Brown A does not have one..

They were a Cherry wood Core inside the Mahogany Neck , I understand.

Both are Fine, play well .

FL Dawg
Nov-24-2012, 3:50pm
A truss rod is preferred, and you'll pay more for a vintage mando that has one.

Gibson marketing, if you read the catalogs, was big on adjustable parts. The adjustable truss rod and bridge were innovations that set them apart from the competition.

There are still many pre truss rod instruments that function perfectly today after a century. There are options for ones with bowed necks, sometimes you can do a compression refret to straighten a bowed neck.

Truss rods can break, freeze, or lose their ability to adjust the neck. Truss rod necks can bow as well.

Nov-25-2012, 3:39pm
I have one with and one without. I prefer the without for sound, however it was planed before I got it rather than trying to straighten the neck. I don't know why , maybe cheaper, but the sound is great. I think the width of the fingerboard makes more difference in sound than the truss rod. The wider the FB the more clear and distinct the sound, however it is slower picking.

Charles Johnson
Nov-25-2012, 10:59pm
Sorry to hijack the thread, but I believe another reason for better sound in the snakeheads is Gibson got better at carving tops as they went along. The early teens tops tend to be a bit thicker, at least thats my impression. I have not gauged them to be sure; its just an observation.

Nov-29-2012, 8:20pm
That is correct. Gail Hester posted this nice thread a few years ago about the differences in top, back, and rib thicknesses among different Gibson years:


As for the truss rods, the only vintage mandolins that I've run into with neck issues tend to be the truss rod models where someone has repeatedly monkeyed around with it to the point of damaging the neck or breaking the truss rod. Customer's instruments generally get whichever one they ask for, but on my personal mandolins, I almost always use a carbon fiber rod with no adjustability. I think I can comfortably say that, as much as anyone I've ever known, I "field test" them to a point where I know they hold up to everything I can give them and still work great!;)