Official Luthiers Forum!

Ok folks, I need help. About a year ago i bought a Johnson tricone from a friend. Being a wannabee luthier, the first thing I did when I got back home with it was to take it apart to see how it works. So I took off the strings, unscrewed the front panel, took out the T-Bar and the cones, tried to take out the wooden rod inside too, but then thought that I should maybe get some more info on these instruments before going that far in the taking apart thing... after all, I bought it mainly to play it, right? So I went about putting the whole thing back together. Long story short, a couple of days later I start to hear a buzzing from what I thought where the cones. Maybe the buzzing was there before, but I didn't notice. So I opened it once more, looked at the cones, didn't see anything. But there was some kind of tape underneath the face plate, all around it (is this normal? what is it for?) which was pretty dried up, so i tried putting the guitar back WITHOUT the plate to see if it was what caused the buzzing. It did help a bit, but not completely. I re-checked the cones, and sure enough at least two of them weren't seated properly, even with the string tension on. If I put some more pressure on the T-Bar whith my finger, I could eventually have a clean(er) sound, but of course I can't afford that when I play...


So the question is this. I know quite a good deal about repair on standard steel string guitars. But how do you setup metal bodied tricones? Not talking about the action or nut, but the cones themselves. How do you make sure that the cones underside match the bottom of the cavity? My woodworking habits would suggest sandpaper, but I doubt it's the right thing to do, I feel the cones are too thin and would easily sand through, if they sand at all... what then? Some kind of felt between the cone and the cavity bottom? Would it dampen the sound too much?


Thanks for any advice or input!!

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Olivier Gauthier
Montreal, QC

I can only offer a little advise here, my only tricone experience is with my Johnson, and a lot of reading. Bottom line, it takes a lot of trial and error to get them adjusted out to eliminate the buzzing. Your instincts were right, don't try sanding the cones, what you want to do is with the cones and t-bridge in place, press lightly on the bridge and tap around the edge of each cone to see if it's seated well. You have to keep rotating the cone and tapping until you find where it makes solid contact with the pan all the way around the cone. When you get all three seated well, I string it up without the coverplate and play it to see if it all works well under tension. If it doesn't, start adjusting again. At least you don't have to keep taking the coverplate on and off this way. Once you get it set right where the cones aren't buzzing mark each cones position on the pan with a sharpie. 1, 2, and 3 alignment marks in case you have to open it up again sometime.

Now you have it playing where the cones don't buzz, you just have to get the rest of the metal pieces together without buzzing problems. The tape under the coverplate was to keep it from buzzing, it might be needed or it might not, just depends on how it goes together. You can just use some masking tape for it if needed. By the way, I tried putting felt under the cones and it killed the sound for me. Another source of buzzing is where the tailpiece and string ends touch the coverplate. I put a small piece of leather under mine for that problem.

All in all, there's a lot of metal to metal contact on a tricone that can give you problems and you just have to chase them down. Once you get it all working right you learn to change your strings one at a time to make sure nothing shifts and starts the chase all over again.

Good luck,
Joe

Joe, thanks a lot for the reply! And I never even thought about the tailpiece and the string VS the plate... I will do all that!

Thanks again

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Olivier Gauthier
Montreal, QC

my experience is only with single cones how ever similar problems arise re rattles.
you could try some auto gasket paper stuff 0.6mm. Cut a gasket for the cone seat if the surface is not dead flat this will help.
I have a gasket on my home made reso and the gasket helped did not affect tone at all.
hope this helps
Luke.

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Cheers Luke

The other thing that might be a problem is if there isn't enough back angle from the saddle to the tail piece you won't have enough pressure on the cone to keep it from buzzing either. That usually requires resetting the neck or raising the saddle heigth and action. Also be aware that if you have enough string back angle then you can get more sustain by shimming the tail piece at the ball ends up. Try shimming it at different heigths and see how it sounds. Or even just pull it up some with your hand and strum it. You'll see what I'm talking about.

If you have a rattle or buzz that you just can't get rid off, you can put silicone sealer on the bottom of the cones, and on the three bridge spikes.
This an old lumberjack trick...Just make sure,there's an even layer on the cones.It works well and doesn't affect the tone. It peels off easily too. That's what they would have used in the 30's, if they'd had it.