An ultrasonic spray-pyrolysis process has been used to prepare an homogeneous T10.5Pb0.5Sr2CaCu2Ox high-temperature superconductor. Depending on experimental conditions, the grain morphology changes from platelet to cauliflower-like, contrary to the three copper layers series. The (Tl/Pb)-Sr-1212 phase has remarkable stability and does not decomposed before melting. The critical temperature onset, about 80 K, is similar to that for samples prepared by the usual sintering methods.