Poor action above the 12th fret

Hey..

I have a MIJ Jaguar. I've replaced the bridge with a mustang bridge as the rollers are more stable for my strings. I do get annoying fret buzz though above the 12th fret (i.e. as I ascend to 13, 14, 15 etc. - it's not too bad after the 16th). The mustang bridge was low and I have slipped a cut up credit card to raise it slightly. This made a slight improvement. The mustang bridge also has an arch across the rollers that didn't seem to be present on the jag bridge.

The bridge is set up as follows:

<--- Neck

X e
X B
X G
X D
X A
X E

I should also add that I use alternate tunings, with different gauge strings - although this doesn't really impact on the problem.

Any hints on how I can fix this up?

Cheers,

Heath

Sounds like maybe you have to tighten your truss rod a little.

The Mustang bridge should have black screws on the bottom of the posts just like the Jaguar's that you can use to adjust the overall height of the bridge.
Did you put credit card under the bridge itself?
I think what you should do is shim the neck at the body end with something thin (say, a credit card!) and raise the bridge to suit. It really does make a huge difference with Jaguars.

Tommy.

Does that (shim) mean take the neck off and plane off a fine amount from underneath where it attaches to the body and then screw it back on? I'd contemplated that but wasn't sure if it'd work.

In regards to the mustang bridge, the one that I have doesn't have those screws (but it has the holes for them) :(

Heath

Try something a little thinner as a shim first, such as a piece of a D'Addario string pack or business card, or as some on the forum prefer, a pick. Put it in the neck route on the body close to the neck pickup and put the neck back on. Afterwards, you may want to raise your bridge a bit.

Yep that's what a shim is. You only need a bit at the neck end to increase the angle. It's also helpful with a Jaguar as the higher break angle of the strings at the bridge will stop the strings doing that annoying thing where they jump off the saddle. Nothing worse than having that happen in the middle of a song at a gig, believe me!
Experiment a bit with thickness but don't be worried if it ends up being fairly thick, it is on my Jaguar. Just make sure you adjust your pickup heights (and shim up the bridge pickup with some mousemat or whatever if it's too low) or the neck pickup will be substantially louder than the bridge.
Do you still have the original Jaguar bridge? The screws come out. In fact they come out so easily they can rattle out and I had to glue mine in place!

Edit: Don't go anywhere near it with a plane! Just put something in the neck pocket to raise the neck a bit at the body end.
Tommy.