Actually, I have a Johnson JM 998S, which is a single cone biscuit bell brass resonator and a Johnson Tri-cone. I replaced the cone and biscuit on the single cone with a National cone and biscuit, and am very happy with the sound. I replaced the coned and bridge on the Tricone, also. As it turns out, the cones really did not need to be replaced on the Tricone as the National cones did not improve the sound as much as I had hoped. I am very pleased with both. Mushroom modification is necessary on the Tricone, however.