Three Generations of P horns Nathan P5
In 1953, when the first P horns were launched by Nathan, they were using a diaphragm disk made of phosphor-bronze. The orifice also has a fairly wide opening with a hole that is oval-shaped in the internal chamber of the horn. The diaphragms of the horn were changed into stainless steel within the first year or two of the construction. The opening of the orifice was changed into a perfectly rounded shape from the previous oval shape.
The initial series of P horns were called the "first generation" P horns. These are the P horn series with the oval shaped inlet and diaphragms made up of phosphor-bronze. The alternates with the circular shaped inlets and stainless diaphragms were considered the "second generation" P horns. The reverberation of the "second generation" horns is mainly the same with the "first generation" horns even though they differ slightly internally. The "first generation" horns just sound a little mellower than the second.
When the castings were changed by Nathan for the P horn series in the late 1977, the tone of the bells 1, 2, 3 and 5 changed. These new castings were considered as the "third generation" P horns. The "old-cast" and "new-cast" was another classification that was commonly heard. The second and first generation horns were classified as the old-cast and the third generation was classified as the new-cast horns.
The old and new cast horns have three main visual differences. The first is that the old casts have "Pat. Pending" that can be found at the bell's foot, while the new casts only have "Pat. Pend." cast. For several years after 1977, the bells 0, 4 and 4A retained the "Pat. Pending" cast, before the "Pat. Pend." started to appear. This was the one and only change that bells 0, 4 and 4A had undergone, as for the tuning and shape of the bells was never changed.
The bell's flare is the second visual difference. The flare is the determining factor for the pitch of the bells. An educated eye can perceive the difference between flares of the old cast and the new cast P series horns. The final difference however is not an "old cast" versus "new cast" variation, though it is still worth noting. The castings of Nathan's back caps were changed sometime before 1977. The older design of the back cap have "Nathan" cast twice while the newer design has "Nathan" cast only once.
