*** The Ampliphase Ancestry ***
The BTA-50J Ampliphase
The BTA-50J was released in 1970 and featured the solid state BTE-20 exciter as standard. There were just 6 tubes in the transmiting circuits, which were the same arrangement as the 50H. The same
line coupling/protection unit was also retained, with another 4 tubes. Very little information on these seems to be available, and it seems that only about six were shipped to stations in the US, and a similar number to overseas users. Rival transmitters, such
as the 317 Doherty from Continental, and the pulse-duartion modulated MW50 from Harris were dominating the market. Ampliphase, it would seem, had passed its sell by date. The last unit to leave the factory in 1977 went to Guatamala where it joined an earlier unit to become a parallel pair.