Intonation on DG-250M

RICK-D15

Hello,

I have a Gitane DG-250M. Above the 12th fret the intonation is slightly flat. I have the original Gitane bridge. Would a new bridge cure this?

I've also experienced a "going flat" of the D string even in the middle registers (3rd thru 8th frets) when the strings get a little old. It's only noticeable when playing octave chords, but it is still annoying. It's not a problem right after a new string change, however.

Thanks,

Rick

Craig Bumgarner

The cool thing about these bridges is intonation changes can be made by sliding the bridge. Up towards the neck to correct flat intonation or toward the tailpiece to correct sharp intonation. Don't loosen the strings, just apply firm, controlled pressure to the bridge with you hands. Move it around until it is the way you like it. You don't have to move both ends. On mine, the bridge at the high E is about 1/8" forward of the mustache and the low E is right on the 'stache or a fraction aft of it. You do not have to change to a new bridge.

Regards intonation problems in the mid range, no doubt intonation is affected by string age as well as type, weight, the way you play, etc. Minor tuning anomalies are often just part of the beast and complete tuning perfection is often just not possible in a guitar. You might find some adjustment of the bridge ala above will help, but it is more likely just a tuning issue. I usually tune up on the open strings then retune slightly for the middle and finally the top end to get it all in sync. I find tuning problems are more noticeable in the mid range and upper ends, especially with octaves, so tuning for these makes sense.

I find electronic tuners are a help with this. Besides the ubiquitous clamp on tuners which win marks for portability if not complete accuracy, I really like the Mini-Tuner, a free download computer based tuner. EXTREMELY accurate; when I get done tuning with this, the guitar is super sweet.

Then, all you have to do is get everyone else in tune with YOU! :P

Craig

RICK-D15

Thanks!

I'll try moving the bridge around.

Josh Hegg

The intonation will be off with the bridge it comes with. Get a Dupont #2 and your problems will be much less.

Cheers

Bob Holo

Josh,

If you could produce a gypsy bridge with b-string intonation adjustment... that'd be your "Bridge Challenge" right there.

B-strings are a nightmare on all guitars that don't have individual intonation adjustment by string. If you average the intonation from the upper to the lower E's (get both the E's accurate by moving the tips of the bridge back and forth till the fretted notes at the 12th are equal to the 12th fret harmonics... if your fretted note is high relative to the harmonic, that means the path length is too short so move that tip of the bridge back a little...) then the A & D & G string will be acceptable... but the B-string is a PITA. The only way to make it right is to give it it's own special little path-length by wagging the crest of the bridge a bit to lengthen it's string-path. Most pre-made (Tusq etc) bridges have this already built in - Gibson archtop bridges have it built in - all other guitars just have the problem. I'm not sure if there is another way to fix it (the B-string problem)


http://www.banjoseen.com/pr350sr.sm%20p ... Bridge.jpg

Josh Hegg

Bob...

I'll play the devils advocate here for a sec...


Have you ever played or known some one or seen some one who plays a French Horn? Thy put their hand in the bell to compensate for the notes. Now.. Think about the B string on a guitar.... If you tuned it just so ever flat and played just that sting with a bit more pressure it would play in tune. Just a though

When I build a bridge I increase the rake as it gets to the E string. This helps allot with the B but it is still a bit flat as you move up the fret board. With a bit of added pressure one can make it perfect.

So... adjustable bridges aside one could play in tune.

On another note... are you going to be at Djangofest SF? It would be great to jam with and see you again.

Cheers

Clay

i recently noticed my intonation was off , so i had a guy adjust the truss rod , i figured that was what was necessary , but then i was mad because the action got lowered quite a bit , what can i do to raise the action back up and still have good intonation? i have a fairly tall bridge , should i shim it?

musicofanatic

Adjusting the trussrod to correct intonation? That's like changing your car's fan belt to fix the transmission...not related. Be that as it may, tightening the trussrod straightens the neck, bringing the strings closer to the frets. Perhaps the adjustment made was too severe. Go back to your gtr tech, explain the situation, and have him take another look at it. Any good tech should be willing to make adjustments on his adjustments. If the neck adjustment is good, then, yes, you will need to shim the bridge. See other posts on this forum for much discussion on the topic.

Josh Hegg

I have to jump in here. Make sure that if you shim your bridge think of it as a measuring procedure. Once you have the action hight you like order the bridge according to that hight. Shims really do kill your tone and also can slide out as you play.

Cheers

Mark

Hi guys,

I teach guitar for a living and build/repair on the weekends.

I just wanted to offer some advice for those of you with intonation problems with floating bridges. (ie. not glued to the top of the guitar)

Firstly - don't bother setting the intonation with old strings - get a new set and you'll be much more successful! Make sure you're happy with the gauge of strings too - if you change gauges in the future you'll need to do this again.

The truss-rod (if it's adjustable) should only be adjusted to straighten a neck or relieve a neck that is too straight. If you don't know what you're doing with the truss rod - LEAVE IT ALONE. You can wind up with bigger problems. It does affect string height which does affect intonation because of the tension placed on a string when you fret it; but only to a minor degree.

If you're going to raise or lower the bridge do this next.
- A higher bridge = better tone,
more difficult to play.

- A lower bridge = weaker tone,
easier to play.

Shim the bridge up if you want to try it, but the less of the bridge in direct contact with the top - the less tone transfer you'll get. Once again I don't recommend removing wood or bone unless you're certain you know what you're doing.

Okay, new strings, slight relief in the neck, bridge height set? Now you can set the intonation.

With the most accurate tuner you can afford, find, borrow etc., tune up the guitar to standard pitch.

Play the open string and check that it is perfect on the tuner. Next, play the note at the 12th fret (don't use the harmonic as some people try - it's not accurate enough). The two notes (open and fretted) should read exactly the same - a perfect octave.

If the fretted note is FLAT - move the bridge toward the neck and then check it again.

If the fretted note is SHARP - move the bridge away from the neck and check it again.

Now repeat the process for the other five strings. If you have a straight bridge saddle (ie. no offset for the 'B' string) then you'll need get the rest of the strings as perfect as possible and put up with the 'B'. This process can be a bit of 'two steps forward - one step backward', but you'll get there. When finished, the bridge is often not at 90 degrees to the centre line of the guitar - it's likely that the treble side will be closer to the neck than the bass side.

This next thing is going to solve a lot of problems in the future! Once your intonation is as perfect as your guitar can be, we want a reference for next time you change strings or incase the bridge gets knocked. We certainly do not want to knife a line on your guitar or mark the top in any way as recommended by some people!

Find yourself a piece of thin plastic (about 2mm thick) that is about 70mm wide and about 250mm long. If you can't find plastic - use stiff cardboard - but plastic will last for ever. Now cut the plastic so that it lays on the top of the guitar, under the strings. One end should touch the neck side of the bridge along it's width and the other end is flush against the end of the neck. Work carefully with files or scrapers to make it a perfect length. It should fit without force but must be touching both the neck and the bridge. Mark which end is 'bridge' and which side is 'up', and then keep it in your guitar case. You may also want to attach a little bit of felt on the flat surface to stop any scratches on the top of your guitar. Next time your on the gig and it gets knocked or you change strings, you'll have the perfect guide...just slide the bridge up to the plastic and get on with your playing!

Good luck!

Mark