Guitartec Repair

08/08/2026

WHAT IS A BRIDGE TRUSS? (rev 2.0)

Acoustic flattop guitars often suffer from what's known as a bellied top. Bellying occurs from years of string pull on the bridge and conversely, the top. This pull can start to tear the bridge off the guitar's top as well as severely stretch the top behind the bridge. In some cases, the stretching is so bad, it can cause internal braces to unglue and/or snap.

Besides this top bellying behind the bridge, the front "dishes" and becomes concave adding even more distortion to the top of your flattop guitar. This is bad because the top must remain flat in order to maintain the sting height (action) and intonation.

Add to this problem, a little bit of shallow neck angle and what you get is basically a bow and arrow. The strings are so high off the fretboard, the guitar is simply unplayable.

How do you fix this?

Well, about 35 years ago, a company in Roswell, New Mexico called JDL brought to market a device known as a Bridge Truss. At first, this device is sold under two different names: The JDL Bridge, Doctor, and the JDL Bridge System.

What a JDL is is a cantilever that hangs down underneath your bridge via an inlaid screw that goes through the bridge. This screw is done covered with a pearl dot.

So this device hangs down under the bridge inside the acoustic guitar (it does NOT touch the back in any way). It has an adjustable 6" wooden sound post installed through it which is manually tensioned. The sound post is adjusted for proper tension using a grub screw to push against the tail block in the guitar (the tail block is one of the strongest part of the guitar. This tensioning counteracts the pull of the strings in the opposite direction and simultaneously pushes the bridge and top perfectly flat again- back to its original position, and holds it there.

It's absolutely brilliant and it literally fixes decades of string-pull damage within just a few minutes after installation.

This is one of the best fixes for an acoustic guitar known to Luther's and Techs. Oddly, many traditional Luthiers have poo poo'd the JLD for decades, claiming that it's not a real repair, however, it is a much more cost-effective repair than the neck reset or top straightening (using heat) they would do. Both of those methods leave you with a warped top again in just a short while in my opinion. The JLD is an absolutely permanent, inexpensive and wonderful repair that not only gives your acoustic guitar new life, but also gives it a better sound.

Traditionally, Bridge trusses have been made from wood, but recently a new plastic version has come out. I just installed two of them and both are holding up just fine. Truss me on this!

More pictures and corrections will be coming, so stay tuned

08/06/2026

The air conditioning is on full today at the shop, so come beat the heat and we'll make your axe play GREAT!

Send a message to learn more

08/04/2026

TRUSS RODS.... All ya need ta know. (this writing will be updated over time as it was written from memory- the ones I have left).

Truss rods in guitar necks are for counteracting string tension, and are found in most guitars that are designed to use steel and nickel strings.

Truss rods either have their adjustments made at the headstock, inside the sound hole or at the heel (or base) of a removable neck like a Fender. Some odd styles adjust on the side of a neck's heel or by using a special key on the heel of a vintage acoustic guitar.

Most nylon stringed guitars do not need truss rods, but some modern classicals, like Cordoba classical giuitars, do have adjustable truss rods. Many, pre-war gut string parlor guitars also do not have truss rods at all.

Martin, the oldest guitar company (1833), for over a century and a half had unadjustable trust rods, either shaped like an Ibeam, a T or a square shape rod. In 1985 Martin went to an adjustable single action compression truss rod.

So, to sum it up, there are essentially 3 types of truss rods found in guitars and basses:

1. un adjustable (or non-adjustable) rods like what you would find in the 1930s-60s "steel reinforced neck" Kay or harmony guitars,

2. a single-action compression truss rod, like what you'd find in a Gibson, Martin or older Fender acoustic or electric guItar. This rod either relaxes or compresses the wood at each end of the neck thus forcing the neck to bend.

3. and the much newer, dual action or 2-way self-contained rod that you find in modern guitars, including many high quality and less expensive Asian-made guitars. This rod does not compress any wood in order to function. It does, however, exert force in either a forward or back bow shape inside the guitar's neck.

Unlike a typical compression rods, a 2-way rod does not compress the wood at each end of the neck in order to make its adjustment. It is completely self-contained and literally just sits in the neck's channel. The neck has no other option than to follow the curvature of the rod that you adjust it to. It's brilliant.

Arguably, the 2-way rod is the most effective rod available and is oddly found in some of the least expensive budget guitars like Fireflys and many Ali Express and Temu guitars.

You generally won't find a 2-way rod in any vintage or re-issue style guitar. MIM Teles & Strats also do not have 2-way rods, but the American version Tele and Strat have what's called a bi-flex rod. This works in a slightly different manner than a traditional "self contained" 2-way rod where the rod expands / pushes or contracts / flexes within its capped-off channel

As for vintage style single-action compression rods, these have to be adjusted in a very careful way in order to keep them working as effective as possible. In other words, adjusting a single action rod improperly can cause it to become less and less effective over time. Many Gibsons come in to the shop with rods that do almost nothing. Most of these guitars still play OK, but fine-tuning their adjustment requires another kind of knowledge and skill.

At our shop, when we see an ineffective compression rod that simply won't adjust the neck properly, there are a few ways to approach this: sometimes lubricating the adjuster nut and inserting additional washer to help compress the wood helps. You could also consider replacing the truss rod, which in most cases is very invasive and expensive to do. EXCEPTION: Rickenbackers allow you to push (hammer) out the rod(s) and push a new one in w/o removing the fretboard.

Another fairly effective way of getting a non-functioning truss rod to adjust is by "preloading" the neck with the hopes of getting it to cooperate.

Pictured below is our neck pre-loading jig. The way it works is... With no sting tension, we loosen the truss rod all the way, then mount and adjust the jig slowly to manually cause a severe back (or forward) bow in the neck. Then, while being held in this sever bow, you then tighten the rod as much as safely possible. You then remove the jig with the hopes that the neck holds this severely bowed condition while the instrument is brought up to tuning pitch.

Once up to pitch, you now can loosen the truss rod (as opposed to tightening it) to bring the neck into correct relief. This can be tricky to do and does not work all the time, but it is the best inexpensive, most non-invasive way to get a dysfunctional neck into the proper relief. Sometimes other work is necessary to accommodate the neck in its new state of straightness.

How's your truss rod doing?

07/27/2026

THIS once-in-a-lifetime SALE BELOW IS NOW OVER, BUT CONGRATS TO EVERYONE THAT GOT THE SET-UP DEAL. MAYBE WE CAN DO IT AGAIN NEXT SUMMER IF BUSINESS ALLOWS.

SET-UP -- SALE -- SET-UP-- SALE-- SET-UP -- SALE-- 2 DAYS ONLY

GUITARTEC REPAIR SALE.... It's not often you see a sale at any guitar repair place, so here ya go....

Since Guitartec is run as an extra-efficient operation, we can sometimes make offers other repair shops can't afford to do..... SO, we are going to have a 2-DAY SUMMER SALE (on set-up work only) this Wednesday JULY 29th and Thursday the 30th....

FIXED BRIDGE GUITARS (ie. acoustic steel strings, Classicals Teles, LPs and other fixed bridge guitars (NO GUITARS WITH A TREM and/or LOCKING NUTS)
SALE PRICE- $70.00 cash + strings, parts and other work + MA tax. YES, you can still bring your own strings and correct fitting parts to help save $$$.

NON-LOCKING TREM GUITARS (Strats, guitars with Bigsbys, Vega Trems, etc) NORMALLY $125.00+ Strings, Parts, Extra Labor and taxes SALE: $99.00 cash + MA taxes. Again, you can bring your own fresh strings, parts.

LOCKING TREM GUITARS, Sale $140.00 + Strings, Parts, Extra Labor and taxes SALE: $119.00 cash + MA taxes. Again, you can bring your own fresh strings, parts.

4 & 5 STRING BASSES will be $70.00 & $80.00 respectively + strings with the same rules as fixed bridge guitars.

ACTIVE INSTRUMENTS- Use above pricing as your price guide and add $15.00. Same rules apply

REPAIRS ARE EXTRA and prices vary, but be kept as low as possible unless you specifically need certain work done.

THIS IS ALSO A THE PERFECT TIME TO CONSIDER UPGRADING YOUR GUITAR'S JACK, POTS, SWITCHES, PUPS AND TUNERS AS SET-UPS WILL RARELY BE THIS INEXPENSIVE AGAIN.

LEGAL P**P...
YOU MUST ASK FOR THE SALE PRICE PRIOR TO WORK BEING DONE!!! These are CASH sale prices, no other forms of payment can be accepted- this is how we roll to keep your costs down. This sale is two (2) days only and all guitars must be picked up by the following Saturday August 1, 2026. Customers may bring up to four (2) guitars. Any additional guitars (whether it's yours (or your friend's) will not qualify for this sale price. Guitars must be functional enough to be set up, meaning the truss rod must work and there may not be any other problems with the guitar (like frozen parts, loose frets or electrical issues) that will cause the set up to take extra time. 7 string, multi-string, Baritone, 6 string bass and any other instruments such as Banjos, Ukes and hand-made instruments are not eligible for this sale.These sale prices are only valid for JULY 29 & 30 2026. We always retain the right to refuse any instrument for this sale and for repair.

07/25/2026

Man, I get to work on some amazing gee-tahs

07/18/2026

LET'S TALK ABOUT LOCKING NUTS FOR A SEC...

07/05/2026

Just got to work on an old 1969 Ampeg Lucite guitar with interchangeable pickups. I used to see these every now and then, but it's been a while. What a blast to bring back to playing condish. See pics below

HERE'S THE STORY ON THESE CLEAR LUCITE AMPEG GUITARS...

In 1969, Ampeg, the guitar and bass amplification company, (formally known as the Amplified Peg Company due to thier first product being a pickup for an upright bass), was financially in dire straights. Through several poor acquisitions, Ampeg needed something to boost sales.... and FAST!

They decide to hire a consultant to help them find a savior for the company before they were forced into bankruptcy. They hired the legendary Dan Armstrong who had his own growing guitar repair and design consultant business near Ampeg.

Dan felt that a new direction from amplification into musical instruments was the path most likely to generate fast revenue for the cash-strapped Ampeg. Along with Ampeg's designers, Dan created the Lucite electric guitar and bass that had user changeable single pickups-either single coil or humbucker.

Whichever pup the player wanted to use could simply be slid into a trough under the strings onto 2 bannana conectors to make the electrical connection. The pup was held in place with a single recessed thumbscrew in the back. These special sealed slide-in pups were designed by the legendary Bill Lawrence, who just happened to be Dan's partner back at his repair shop.

The neck on this 10lb guitar was a maple/rosewood 24 (2 octave) slim profile neck that was bolted on under the pickguard with 4 short carriage bolts and nuts. It had jumbo frets and was made very well with excellent Schaller 21:1 ratio chrome tuners.

Much like a Fender Strat, the pickguard on this beast housed all the electronics and covered the neck bolts. It also had Dan's name on it. I believe it was made from fake wood-grained Formica (countertop covering).

Interestingly, the guitar used a Danelectro straight wooden bridge saddle (no doubt from Ampeg's acquired Dano inventory). This design left the guitar with no bridge height adjustment, which I guess is just as well as the pup had no height adjustment either. You'd literally have to shim the neck if a different action was desired. This was NOT optimal for a $240.(1969 $$$) axe like this, but I digress.

Dan chose the clear Lucite body because it was an inexpensive, transparent, durable and shatter resistant acrylic, which was the opposite of your typical electric guitar- commonly made from wood. Plus, Lucite was all-the-rage on TV... it was everywhere, including floor wax (Future Floor Wax), so this space-age material got a ton of TV publicity.

Now for the weird part of the story.... half way through the design and production of these Lucite instruments, Ampeg's Production Manager quit due to non-payment. Dan was asked to take over the job to see them through to completion. He did exactly that!

Well...remember when I said Ampeg had made some bad business choices that got them into this horrible financial bind? Well, one of those choices was buying all the DanElectro inventory when Danelectro went out of business. All of the inventory- necks, bodies, electronics, hardware and who knows what else was sitting on pallets at Ampeg waiting for someone to use it for something.

Since Ampeg had no cash to pay Dan, he instead agreed to take all the Danelectro inventory off their hands. This led to Dan making his own version Danelectro version of the Dano guitars and basses.

Unfortunately, nothing in any of this story saved Ampeg or Dan Armstrong from financial burden. Ampeg declared bankruptcy and Dan had to go on fixin' guitars and design things for other companies to stay solvent.

I will update and make corrections to this writing as needed.

07/04/2026

HAPPY 4TH OF JULY EVERYONE!!! I hope everyone is having a safe holiday.

Just so you know GUITARTEC REPAIR is OPEN today (the 4th) from 2:30-7:30PM.

The air conditioner is on full blast so it is nice and comfy in the shop.

COME ONE, COME ALL, and don't forget your axe!!!

06/20/2026

Here is a pre-built (but not fully completed) KIT dreadnaught acoustic guitar that is on sale now at only $289. cash + tax

It was built in-house to have some very cool features not normally found in off-the-shelf guitars.

It has 3 features that make it very special, and you can finish it (or not) any way you like. (we highly recommend you give it some sort of finish which can be fun and simple to do). This is a nice, clean build and has a Bridge Truss System installed so the top will always remain flat (instead of warping like so many acoustics do over time).

Most importantly, we paid a lot of attention to the neck angle when it was being installed. This gives the best action with the ability to keep it very adjustable over many years (often, off-the-shelf acoustics have little to no ability to have its action adjusted due to poor neck angle). Check out the pics and video.

DISCLAIMER... Please know my playing ability is presented to demonstrate the most out of a guitar, not dazzle anyone with great song. Due to this, I often play the same pieces or types of music so you can hopefully compare apples to apples and have some sort of reliable reference. Playing great songs is for you to do. I just play in different registers to let you hear the guitar's ability to play in tune (intonation), nuances, overall quality, projection of sound and any electronics or effects it has. I generally play w/o a pick which is just my style and may not show an acoustic's natural volume potential. All guitars are currently videoed on an iPhone 12 w/o any sound or picture editing.

06/18/2026

A customer of ours recently was in Japan and visited the legendary site of the Matsumoku Guitar Factory that closed in 1987. The Matsumoku factory brought us many wonderful guitars from many companies such as Aria, Epiphone, Univox, Electa, Westone, Greco, Washburn, Conrad, Lyle, Shaftsbury, Phantom, Skylark, Domino, Fandel, and Vantage,