Setting Intonation on a Wrapover or Stop-Tailpiece Bridge (Including PRS)
Some guitars have a wrapover tailpice style bridge. If you’re not familiar with these, imagine the tailpiece where the strings anchor on a Les Paul. That’s it.
The strings go through from the front, wrapover the rear of the tailpiece and then make their way up the neck.
“Why?” you cry, “Why would you do such a thing?”
Well, originally, because it was cheap. Costs less to just bung on a tailpiece than to pay for a tun-o-matic bridge as well. The ‘student’ model, entry-level guitars like the Les Paul Junior came with just a wrapover bridge when they started out.
And here’s the thing… They can sound great. You see, good coupling between bridge and body is a big part of good guitar tone. With one of these wrapovers, there’s nothing else. It’s a hunk of metal bolted to a guitar. Not much to get in the way of tasty tone.
The problem, of course, comes when we consider intonation.
On your regular Strat bridge or tun-o-matic, we can individually set each string saddle to the optimal location for that string’s intonation.
On a wrapover… not so much.
It’s compromise city. The bridge is adjustable ‘overall’.
By that, I mean that, on the bridge, behind where it mounts on each post, is a small ‘grub-screw’. Adusting the screw on either the bass or treble side can change the angle the bridge mounts at.
For instance, if you adjust the bass-side screw clockwise, it pushes against the mounting post and moves that side of the bridge further back. Essentially, the overall angle of the bridge can be changed and this can be used to approximate a good intonation.
On a guitar, this isn’t really a recipe for perfect intonation. That’s the thing though—if you’re playing one of these, you’re accepting the compromise.
INTONATION PROCEDURE
First up, let’s recap our intonation prerequisites.
The rest of your setup must be right for you before you start. Intonation is the last thing to set so get your action, relief, nut and pickups sorted out first. You should have fresh strings (of your usual gauge and brand) installed, properly stretched, and tuned up as normal.
Remember, always check intonation and tuning with the guitar in the playing position (i.e. not lying on a table or counter but upright as if you were playing it).
The basic theory is the same as any other guitar:
Pick the open string and verify it’s in tune.
Fret at the 12th fret and pick this note. Compare it to the open string—is it flat or sharp?
If the 12th fret note is flat, the string must be 'shortened' by moving the bridge forward a little.
If the 12th fret note is sharp, lengthen the string by moving the bridge back a little.
Retune the open string and go back to 1.
Of course, on a wrapover tailpiece bridge, you can’t do each string individually. Instead, you'll adjust the angle of the bridge to get things in the ballpark.
I like to set the outside strings first. Get them correct first.
Then check the middle strings and see how they seem.
From there, you can tweak the overall angle a little to ‘balance up’ the intonation so that no one string is too far out.
Remember… compromise.
PRE-INTONATED WRAPOVER BRIDGES (LIKE THE PRS)
Some wrapovers come with a moulded or carved ‘intonation line’. This gives you an advantage over the straight line of the simplest of these bridges. The intonation line provides a ‘good for most people’ intonation by replicating the stagger of a properly intonated guitar.
The PRS bridge is probably the most recognisable of these pre-intonated models. Each string bears off a differnt point on a 'staggered front end’ of the bridge. Using the grub screws to get the bridge to a good angle will generally give a pretty good overall intonation.
Again, start with the outside strings and then check the others.
INDIVIDUALLY ADJUSTABLE/INTONABLE WRAPOVER BRIDGES
You can get wrapover bridges that have adjustable saddles built in. These can be a good way to improve your intonation without changing your guitar’s look or vibe too much. Think of these as a tun-o-matic built into a stop-tailpiece. Use the grub screws to set the overall angle and get things close and then adjust each saddle the same way you would for a tun-o-matic.
If you're planning to buy one of these, make sure it's right for your guitar. Some of them can be taller than the regular tailpiece bridge which might cause problems getting a good action.
This article written by Gerry Hayes and first published at hazeguitars.com